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4801 lines
123 KiB
4801 lines
123 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* linux/kernel/signal.c |
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* |
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* Copyright (C) 1991, 1992 Linus Torvalds |
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* |
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* 1997-11-02 Modified for POSIX.1b signals by Richard Henderson |
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* |
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* 2003-06-02 Jim Houston - Concurrent Computer Corp. |
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* Changes to use preallocated sigqueue structures |
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* to allow signals to be sent reliably. |
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*/ |
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|
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#include <linux/slab.h> |
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#include <linux/export.h> |
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#include <linux/init.h> |
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#include <linux/sched/mm.h> |
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#include <linux/sched/user.h> |
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#include <linux/sched/debug.h> |
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#include <linux/sched/task.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/sched/cputime.h> |
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#include <linux/file.h> |
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#include <linux/fs.h> |
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#include <linux/proc_fs.h> |
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#include <linux/tty.h> |
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#include <linux/binfmts.h> |
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#include <linux/coredump.h> |
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#include <linux/security.h> |
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#include <linux/syscalls.h> |
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#include <linux/ptrace.h> |
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#include <linux/signal.h> |
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#include <linux/signalfd.h> |
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#include <linux/ratelimit.h> |
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#include <linux/task_work.h> |
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#include <linux/capability.h> |
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#include <linux/freezer.h> |
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#include <linux/pid_namespace.h> |
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#include <linux/nsproxy.h> |
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#include <linux/user_namespace.h> |
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#include <linux/uprobes.h> |
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#include <linux/compat.h> |
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#include <linux/cn_proc.h> |
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#include <linux/compiler.h> |
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#include <linux/posix-timers.h> |
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#include <linux/cgroup.h> |
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#include <linux/audit.h> |
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|
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#define CREATE_TRACE_POINTS |
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#include <trace/events/signal.h> |
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|
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#include <asm/param.h> |
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#include <linux/uaccess.h> |
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#include <asm/unistd.h> |
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#include <asm/siginfo.h> |
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#include <asm/cacheflush.h> |
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#include <asm/syscall.h> /* for syscall_get_* */ |
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|
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/* |
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* SLAB caches for signal bits. |
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*/ |
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static struct kmem_cache *sigqueue_cachep; |
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|
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int print_fatal_signals __read_mostly; |
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|
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static void __user *sig_handler(struct task_struct *t, int sig) |
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{ |
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return t->sighand->action[sig - 1].sa.sa_handler; |
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} |
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static inline bool sig_handler_ignored(void __user *handler, int sig) |
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{ |
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/* Is it explicitly or implicitly ignored? */ |
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return handler == SIG_IGN || |
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(handler == SIG_DFL && sig_kernel_ignore(sig)); |
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} |
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|
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static bool sig_task_ignored(struct task_struct *t, int sig, bool force) |
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{ |
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void __user *handler; |
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|
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handler = sig_handler(t, sig); |
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|
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/* SIGKILL and SIGSTOP may not be sent to the global init */ |
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if (unlikely(is_global_init(t) && sig_kernel_only(sig))) |
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return true; |
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if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && |
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handler == SIG_DFL && !(force && sig_kernel_only(sig))) |
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return true; |
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|
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/* Only allow kernel generated signals to this kthread */ |
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if (unlikely((t->flags & PF_KTHREAD) && |
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(handler == SIG_KTHREAD_KERNEL) && !force)) |
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return true; |
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return sig_handler_ignored(handler, sig); |
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} |
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static bool sig_ignored(struct task_struct *t, int sig, bool force) |
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{ |
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/* |
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* Blocked signals are never ignored, since the |
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* signal handler may change by the time it is |
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* unblocked. |
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*/ |
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if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
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return false; |
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|
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/* |
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* Tracers may want to know about even ignored signal unless it |
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* is SIGKILL which can't be reported anyway but can be ignored |
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* by SIGNAL_UNKILLABLE task. |
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*/ |
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if (t->ptrace && sig != SIGKILL) |
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return false; |
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|
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return sig_task_ignored(t, sig, force); |
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} |
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|
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/* |
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* Re-calculate pending state from the set of locally pending |
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* signals, globally pending signals, and blocked signals. |
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*/ |
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static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked) |
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{ |
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unsigned long ready; |
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long i; |
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|
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switch (_NSIG_WORDS) { |
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default: |
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for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) |
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ready |= signal->sig[i] &~ blocked->sig[i]; |
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break; |
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|
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case 4: ready = signal->sig[3] &~ blocked->sig[3]; |
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ready |= signal->sig[2] &~ blocked->sig[2]; |
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ready |= signal->sig[1] &~ blocked->sig[1]; |
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ready |= signal->sig[0] &~ blocked->sig[0]; |
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break; |
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|
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case 2: ready = signal->sig[1] &~ blocked->sig[1]; |
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ready |= signal->sig[0] &~ blocked->sig[0]; |
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break; |
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|
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case 1: ready = signal->sig[0] &~ blocked->sig[0]; |
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} |
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return ready != 0; |
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} |
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#define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) |
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|
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static bool recalc_sigpending_tsk(struct task_struct *t) |
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{ |
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if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) || |
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PENDING(&t->pending, &t->blocked) || |
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PENDING(&t->signal->shared_pending, &t->blocked) || |
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cgroup_task_frozen(t)) { |
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set_tsk_thread_flag(t, TIF_SIGPENDING); |
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return true; |
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} |
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|
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/* |
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* We must never clear the flag in another thread, or in current |
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* when it's possible the current syscall is returning -ERESTART*. |
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* So we don't clear it here, and only callers who know they should do. |
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*/ |
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return false; |
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} |
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/* |
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* After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. |
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* This is superfluous when called on current, the wakeup is a harmless no-op. |
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*/ |
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void recalc_sigpending_and_wake(struct task_struct *t) |
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{ |
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if (recalc_sigpending_tsk(t)) |
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signal_wake_up(t, 0); |
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} |
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|
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void recalc_sigpending(void) |
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{ |
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if (!recalc_sigpending_tsk(current) && !freezing(current)) |
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clear_thread_flag(TIF_SIGPENDING); |
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|
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} |
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EXPORT_SYMBOL(recalc_sigpending); |
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|
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void calculate_sigpending(void) |
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{ |
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/* Have any signals or users of TIF_SIGPENDING been delayed |
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* until after fork? |
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*/ |
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spin_lock_irq(¤t->sighand->siglock); |
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set_tsk_thread_flag(current, TIF_SIGPENDING); |
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recalc_sigpending(); |
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spin_unlock_irq(¤t->sighand->siglock); |
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} |
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|
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/* Given the mask, find the first available signal that should be serviced. */ |
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|
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#define SYNCHRONOUS_MASK \ |
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(sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ |
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sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
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|
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int next_signal(struct sigpending *pending, sigset_t *mask) |
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{ |
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unsigned long i, *s, *m, x; |
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int sig = 0; |
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s = pending->signal.sig; |
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m = mask->sig; |
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/* |
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* Handle the first word specially: it contains the |
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* synchronous signals that need to be dequeued first. |
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*/ |
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x = *s &~ *m; |
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if (x) { |
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if (x & SYNCHRONOUS_MASK) |
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x &= SYNCHRONOUS_MASK; |
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sig = ffz(~x) + 1; |
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return sig; |
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} |
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|
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switch (_NSIG_WORDS) { |
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default: |
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for (i = 1; i < _NSIG_WORDS; ++i) { |
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x = *++s &~ *++m; |
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if (!x) |
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continue; |
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sig = ffz(~x) + i*_NSIG_BPW + 1; |
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break; |
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} |
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break; |
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|
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case 2: |
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x = s[1] &~ m[1]; |
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if (!x) |
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break; |
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sig = ffz(~x) + _NSIG_BPW + 1; |
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break; |
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|
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case 1: |
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/* Nothing to do */ |
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break; |
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} |
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|
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return sig; |
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} |
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|
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static inline void print_dropped_signal(int sig) |
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{ |
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static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); |
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|
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if (!print_fatal_signals) |
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return; |
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|
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if (!__ratelimit(&ratelimit_state)) |
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return; |
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pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
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current->comm, current->pid, sig); |
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} |
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/** |
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* task_set_jobctl_pending - set jobctl pending bits |
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* @task: target task |
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* @mask: pending bits to set |
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* |
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* Clear @mask from @task->jobctl. @mask must be subset of |
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* %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | |
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* %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is |
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* cleared. If @task is already being killed or exiting, this function |
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* becomes noop. |
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* |
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* CONTEXT: |
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* Must be called with @task->sighand->siglock held. |
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* |
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* RETURNS: |
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* %true if @mask is set, %false if made noop because @task was dying. |
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*/ |
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bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
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{ |
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BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | |
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JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); |
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BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); |
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if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) |
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return false; |
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if (mask & JOBCTL_STOP_SIGMASK) |
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task->jobctl &= ~JOBCTL_STOP_SIGMASK; |
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task->jobctl |= mask; |
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return true; |
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} |
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/** |
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* task_clear_jobctl_trapping - clear jobctl trapping bit |
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* @task: target task |
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* |
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* If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
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* Clear it and wake up the ptracer. Note that we don't need any further |
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* locking. @task->siglock guarantees that @task->parent points to the |
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* ptracer. |
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* |
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* CONTEXT: |
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* Must be called with @task->sighand->siglock held. |
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*/ |
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void task_clear_jobctl_trapping(struct task_struct *task) |
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{ |
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if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
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task->jobctl &= ~JOBCTL_TRAPPING; |
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smp_mb(); /* advised by wake_up_bit() */ |
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wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
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} |
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} |
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/** |
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* task_clear_jobctl_pending - clear jobctl pending bits |
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* @task: target task |
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* @mask: pending bits to clear |
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* |
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* Clear @mask from @task->jobctl. @mask must be subset of |
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* %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other |
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* STOP bits are cleared together. |
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* |
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* If clearing of @mask leaves no stop or trap pending, this function calls |
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* task_clear_jobctl_trapping(). |
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* |
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* CONTEXT: |
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* Must be called with @task->sighand->siglock held. |
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*/ |
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void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) |
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{ |
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BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
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if (mask & JOBCTL_STOP_PENDING) |
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mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; |
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task->jobctl &= ~mask; |
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if (!(task->jobctl & JOBCTL_PENDING_MASK)) |
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task_clear_jobctl_trapping(task); |
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} |
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|
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/** |
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* task_participate_group_stop - participate in a group stop |
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* @task: task participating in a group stop |
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* |
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* @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
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* Group stop states are cleared and the group stop count is consumed if |
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* %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
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* stop, the appropriate `SIGNAL_*` flags are set. |
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* |
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* CONTEXT: |
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* Must be called with @task->sighand->siglock held. |
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* |
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* RETURNS: |
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* %true if group stop completion should be notified to the parent, %false |
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* otherwise. |
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*/ |
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static bool task_participate_group_stop(struct task_struct *task) |
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{ |
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struct signal_struct *sig = task->signal; |
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bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
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|
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WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
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task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
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if (!consume) |
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return false; |
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|
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if (!WARN_ON_ONCE(sig->group_stop_count == 0)) |
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sig->group_stop_count--; |
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|
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/* |
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* Tell the caller to notify completion iff we are entering into a |
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* fresh group stop. Read comment in do_signal_stop() for details. |
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*/ |
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if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { |
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signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED); |
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return true; |
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} |
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return false; |
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} |
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void task_join_group_stop(struct task_struct *task) |
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{ |
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unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK; |
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struct signal_struct *sig = current->signal; |
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|
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if (sig->group_stop_count) { |
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sig->group_stop_count++; |
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mask |= JOBCTL_STOP_CONSUME; |
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} else if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
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return; |
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|
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/* Have the new thread join an on-going signal group stop */ |
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task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING); |
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} |
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|
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/* |
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* allocate a new signal queue record |
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* - this may be called without locks if and only if t == current, otherwise an |
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* appropriate lock must be held to stop the target task from exiting |
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*/ |
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static struct sigqueue * |
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__sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags, |
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int override_rlimit, const unsigned int sigqueue_flags) |
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{ |
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struct sigqueue *q = NULL; |
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struct ucounts *ucounts = NULL; |
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long sigpending; |
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|
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/* |
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* Protect access to @t credentials. This can go away when all |
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* callers hold rcu read lock. |
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* |
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* NOTE! A pending signal will hold on to the user refcount, |
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* and we get/put the refcount only when the sigpending count |
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* changes from/to zero. |
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*/ |
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rcu_read_lock(); |
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ucounts = task_ucounts(t); |
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sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); |
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rcu_read_unlock(); |
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if (!sigpending) |
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return NULL; |
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|
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if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) { |
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q = kmem_cache_alloc(sigqueue_cachep, gfp_flags); |
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} else { |
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print_dropped_signal(sig); |
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} |
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|
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if (unlikely(q == NULL)) { |
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dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); |
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} else { |
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INIT_LIST_HEAD(&q->list); |
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q->flags = sigqueue_flags; |
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q->ucounts = ucounts; |
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} |
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return q; |
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} |
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|
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static void __sigqueue_free(struct sigqueue *q) |
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{ |
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if (q->flags & SIGQUEUE_PREALLOC) |
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return; |
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if (q->ucounts) { |
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dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING); |
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q->ucounts = NULL; |
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} |
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kmem_cache_free(sigqueue_cachep, q); |
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} |
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|
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void flush_sigqueue(struct sigpending *queue) |
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{ |
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struct sigqueue *q; |
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|
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sigemptyset(&queue->signal); |
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while (!list_empty(&queue->list)) { |
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q = list_entry(queue->list.next, struct sigqueue , list); |
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list_del_init(&q->list); |
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__sigqueue_free(q); |
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} |
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} |
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|
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/* |
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* Flush all pending signals for this kthread. |
|
*/ |
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void flush_signals(struct task_struct *t) |
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{ |
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unsigned long flags; |
|
|
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spin_lock_irqsave(&t->sighand->siglock, flags); |
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clear_tsk_thread_flag(t, TIF_SIGPENDING); |
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flush_sigqueue(&t->pending); |
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flush_sigqueue(&t->signal->shared_pending); |
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spin_unlock_irqrestore(&t->sighand->siglock, flags); |
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} |
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EXPORT_SYMBOL(flush_signals); |
|
|
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#ifdef CONFIG_POSIX_TIMERS |
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static void __flush_itimer_signals(struct sigpending *pending) |
|
{ |
|
sigset_t signal, retain; |
|
struct sigqueue *q, *n; |
|
|
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signal = pending->signal; |
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sigemptyset(&retain); |
|
|
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list_for_each_entry_safe(q, n, &pending->list, list) { |
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int sig = q->info.si_signo; |
|
|
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if (likely(q->info.si_code != SI_TIMER)) { |
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sigaddset(&retain, sig); |
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} else { |
|
sigdelset(&signal, sig); |
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list_del_init(&q->list); |
|
__sigqueue_free(q); |
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} |
|
} |
|
|
|
sigorsets(&pending->signal, &signal, &retain); |
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} |
|
|
|
void flush_itimer_signals(void) |
|
{ |
|
struct task_struct *tsk = current; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&tsk->sighand->siglock, flags); |
|
__flush_itimer_signals(&tsk->pending); |
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__flush_itimer_signals(&tsk->signal->shared_pending); |
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spin_unlock_irqrestore(&tsk->sighand->siglock, flags); |
|
} |
|
#endif |
|
|
|
void ignore_signals(struct task_struct *t) |
|
{ |
|
int i; |
|
|
|
for (i = 0; i < _NSIG; ++i) |
|
t->sighand->action[i].sa.sa_handler = SIG_IGN; |
|
|
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flush_signals(t); |
|
} |
|
|
|
/* |
|
* Flush all handlers for a task. |
|
*/ |
|
|
|
void |
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flush_signal_handlers(struct task_struct *t, int force_default) |
|
{ |
|
int i; |
|
struct k_sigaction *ka = &t->sighand->action[0]; |
|
for (i = _NSIG ; i != 0 ; i--) { |
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if (force_default || ka->sa.sa_handler != SIG_IGN) |
|
ka->sa.sa_handler = SIG_DFL; |
|
ka->sa.sa_flags = 0; |
|
#ifdef __ARCH_HAS_SA_RESTORER |
|
ka->sa.sa_restorer = NULL; |
|
#endif |
|
sigemptyset(&ka->sa.sa_mask); |
|
ka++; |
|
} |
|
} |
|
|
|
bool unhandled_signal(struct task_struct *tsk, int sig) |
|
{ |
|
void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
|
if (is_global_init(tsk)) |
|
return true; |
|
|
|
if (handler != SIG_IGN && handler != SIG_DFL) |
|
return false; |
|
|
|
/* if ptraced, let the tracer determine */ |
|
return !tsk->ptrace; |
|
} |
|
|
|
static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info, |
|
bool *resched_timer) |
|
{ |
|
struct sigqueue *q, *first = NULL; |
|
|
|
/* |
|
* Collect the siginfo appropriate to this signal. Check if |
|
* there is another siginfo for the same signal. |
|
*/ |
|
list_for_each_entry(q, &list->list, list) { |
|
if (q->info.si_signo == sig) { |
|
if (first) |
|
goto still_pending; |
|
first = q; |
|
} |
|
} |
|
|
|
sigdelset(&list->signal, sig); |
|
|
|
if (first) { |
|
still_pending: |
|
list_del_init(&first->list); |
|
copy_siginfo(info, &first->info); |
|
|
|
*resched_timer = |
|
(first->flags & SIGQUEUE_PREALLOC) && |
|
(info->si_code == SI_TIMER) && |
|
(info->si_sys_private); |
|
|
|
__sigqueue_free(first); |
|
} else { |
|
/* |
|
* Ok, it wasn't in the queue. This must be |
|
* a fast-pathed signal or we must have been |
|
* out of queue space. So zero out the info. |
|
*/ |
|
clear_siginfo(info); |
|
info->si_signo = sig; |
|
info->si_errno = 0; |
|
info->si_code = SI_USER; |
|
info->si_pid = 0; |
|
info->si_uid = 0; |
|
} |
|
} |
|
|
|
static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, |
|
kernel_siginfo_t *info, bool *resched_timer) |
|
{ |
|
int sig = next_signal(pending, mask); |
|
|
|
if (sig) |
|
collect_signal(sig, pending, info, resched_timer); |
|
return sig; |
|
} |
|
|
|
/* |
|
* Dequeue a signal and return the element to the caller, which is |
|
* expected to free it. |
|
* |
|
* All callers have to hold the siglock. |
|
*/ |
|
int dequeue_signal(struct task_struct *tsk, sigset_t *mask, |
|
kernel_siginfo_t *info, enum pid_type *type) |
|
{ |
|
bool resched_timer = false; |
|
int signr; |
|
|
|
/* We only dequeue private signals from ourselves, we don't let |
|
* signalfd steal them |
|
*/ |
|
*type = PIDTYPE_PID; |
|
signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer); |
|
if (!signr) { |
|
*type = PIDTYPE_TGID; |
|
signr = __dequeue_signal(&tsk->signal->shared_pending, |
|
mask, info, &resched_timer); |
|
#ifdef CONFIG_POSIX_TIMERS |
|
/* |
|
* itimer signal ? |
|
* |
|
* itimers are process shared and we restart periodic |
|
* itimers in the signal delivery path to prevent DoS |
|
* attacks in the high resolution timer case. This is |
|
* compliant with the old way of self-restarting |
|
* itimers, as the SIGALRM is a legacy signal and only |
|
* queued once. Changing the restart behaviour to |
|
* restart the timer in the signal dequeue path is |
|
* reducing the timer noise on heavy loaded !highres |
|
* systems too. |
|
*/ |
|
if (unlikely(signr == SIGALRM)) { |
|
struct hrtimer *tmr = &tsk->signal->real_timer; |
|
|
|
if (!hrtimer_is_queued(tmr) && |
|
tsk->signal->it_real_incr != 0) { |
|
hrtimer_forward(tmr, tmr->base->get_time(), |
|
tsk->signal->it_real_incr); |
|
hrtimer_restart(tmr); |
|
} |
|
} |
|
#endif |
|
} |
|
|
|
recalc_sigpending(); |
|
if (!signr) |
|
return 0; |
|
|
|
if (unlikely(sig_kernel_stop(signr))) { |
|
/* |
|
* Set a marker that we have dequeued a stop signal. Our |
|
* caller might release the siglock and then the pending |
|
* stop signal it is about to process is no longer in the |
|
* pending bitmasks, but must still be cleared by a SIGCONT |
|
* (and overruled by a SIGKILL). So those cases clear this |
|
* shared flag after we've set it. Note that this flag may |
|
* remain set after the signal we return is ignored or |
|
* handled. That doesn't matter because its only purpose |
|
* is to alert stop-signal processing code when another |
|
* processor has come along and cleared the flag. |
|
*/ |
|
current->jobctl |= JOBCTL_STOP_DEQUEUED; |
|
} |
|
#ifdef CONFIG_POSIX_TIMERS |
|
if (resched_timer) { |
|
/* |
|
* Release the siglock to ensure proper locking order |
|
* of timer locks outside of siglocks. Note, we leave |
|
* irqs disabled here, since the posix-timers code is |
|
* about to disable them again anyway. |
|
*/ |
|
spin_unlock(&tsk->sighand->siglock); |
|
posixtimer_rearm(info); |
|
spin_lock(&tsk->sighand->siglock); |
|
|
|
/* Don't expose the si_sys_private value to userspace */ |
|
info->si_sys_private = 0; |
|
} |
|
#endif |
|
return signr; |
|
} |
|
EXPORT_SYMBOL_GPL(dequeue_signal); |
|
|
|
static int dequeue_synchronous_signal(kernel_siginfo_t *info) |
|
{ |
|
struct task_struct *tsk = current; |
|
struct sigpending *pending = &tsk->pending; |
|
struct sigqueue *q, *sync = NULL; |
|
|
|
/* |
|
* Might a synchronous signal be in the queue? |
|
*/ |
|
if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK)) |
|
return 0; |
|
|
|
/* |
|
* Return the first synchronous signal in the queue. |
|
*/ |
|
list_for_each_entry(q, &pending->list, list) { |
|
/* Synchronous signals have a positive si_code */ |
|
if ((q->info.si_code > SI_USER) && |
|
(sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) { |
|
sync = q; |
|
goto next; |
|
} |
|
} |
|
return 0; |
|
next: |
|
/* |
|
* Check if there is another siginfo for the same signal. |
|
*/ |
|
list_for_each_entry_continue(q, &pending->list, list) { |
|
if (q->info.si_signo == sync->info.si_signo) |
|
goto still_pending; |
|
} |
|
|
|
sigdelset(&pending->signal, sync->info.si_signo); |
|
recalc_sigpending(); |
|
still_pending: |
|
list_del_init(&sync->list); |
|
copy_siginfo(info, &sync->info); |
|
__sigqueue_free(sync); |
|
return info->si_signo; |
|
} |
|
|
|
/* |
|
* Tell a process that it has a new active signal.. |
|
* |
|
* NOTE! we rely on the previous spin_lock to |
|
* lock interrupts for us! We can only be called with |
|
* "siglock" held, and the local interrupt must |
|
* have been disabled when that got acquired! |
|
* |
|
* No need to set need_resched since signal event passing |
|
* goes through ->blocked |
|
*/ |
|
void signal_wake_up_state(struct task_struct *t, unsigned int state) |
|
{ |
|
lockdep_assert_held(&t->sighand->siglock); |
|
|
|
set_tsk_thread_flag(t, TIF_SIGPENDING); |
|
|
|
/* |
|
* TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
|
* case. We don't check t->state here because there is a race with it |
|
* executing another processor and just now entering stopped state. |
|
* By using wake_up_state, we ensure the process will wake up and |
|
* handle its death signal. |
|
*/ |
|
if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
|
kick_process(t); |
|
} |
|
|
|
/* |
|
* Remove signals in mask from the pending set and queue. |
|
* Returns 1 if any signals were found. |
|
* |
|
* All callers must be holding the siglock. |
|
*/ |
|
static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
|
{ |
|
struct sigqueue *q, *n; |
|
sigset_t m; |
|
|
|
sigandsets(&m, mask, &s->signal); |
|
if (sigisemptyset(&m)) |
|
return; |
|
|
|
sigandnsets(&s->signal, &s->signal, mask); |
|
list_for_each_entry_safe(q, n, &s->list, list) { |
|
if (sigismember(mask, q->info.si_signo)) { |
|
list_del_init(&q->list); |
|
__sigqueue_free(q); |
|
} |
|
} |
|
} |
|
|
|
static inline int is_si_special(const struct kernel_siginfo *info) |
|
{ |
|
return info <= SEND_SIG_PRIV; |
|
} |
|
|
|
static inline bool si_fromuser(const struct kernel_siginfo *info) |
|
{ |
|
return info == SEND_SIG_NOINFO || |
|
(!is_si_special(info) && SI_FROMUSER(info)); |
|
} |
|
|
|
/* |
|
* called with RCU read lock from check_kill_permission() |
|
*/ |
|
static bool kill_ok_by_cred(struct task_struct *t) |
|
{ |
|
const struct cred *cred = current_cred(); |
|
const struct cred *tcred = __task_cred(t); |
|
|
|
return uid_eq(cred->euid, tcred->suid) || |
|
uid_eq(cred->euid, tcred->uid) || |
|
uid_eq(cred->uid, tcred->suid) || |
|
uid_eq(cred->uid, tcred->uid) || |
|
ns_capable(tcred->user_ns, CAP_KILL); |
|
} |
|
|
|
/* |
|
* Bad permissions for sending the signal |
|
* - the caller must hold the RCU read lock |
|
*/ |
|
static int check_kill_permission(int sig, struct kernel_siginfo *info, |
|
struct task_struct *t) |
|
{ |
|
struct pid *sid; |
|
int error; |
|
|
|
if (!valid_signal(sig)) |
|
return -EINVAL; |
|
|
|
if (!si_fromuser(info)) |
|
return 0; |
|
|
|
error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
|
if (error) |
|
return error; |
|
|
|
if (!same_thread_group(current, t) && |
|
!kill_ok_by_cred(t)) { |
|
switch (sig) { |
|
case SIGCONT: |
|
sid = task_session(t); |
|
/* |
|
* We don't return the error if sid == NULL. The |
|
* task was unhashed, the caller must notice this. |
|
*/ |
|
if (!sid || sid == task_session(current)) |
|
break; |
|
fallthrough; |
|
default: |
|
return -EPERM; |
|
} |
|
} |
|
|
|
return security_task_kill(t, info, sig, NULL); |
|
} |
|
|
|
/** |
|
* ptrace_trap_notify - schedule trap to notify ptracer |
|
* @t: tracee wanting to notify tracer |
|
* |
|
* This function schedules sticky ptrace trap which is cleared on the next |
|
* TRAP_STOP to notify ptracer of an event. @t must have been seized by |
|
* ptracer. |
|
* |
|
* If @t is running, STOP trap will be taken. If trapped for STOP and |
|
* ptracer is listening for events, tracee is woken up so that it can |
|
* re-trap for the new event. If trapped otherwise, STOP trap will be |
|
* eventually taken without returning to userland after the existing traps |
|
* are finished by PTRACE_CONT. |
|
* |
|
* CONTEXT: |
|
* Must be called with @task->sighand->siglock held. |
|
*/ |
|
static void ptrace_trap_notify(struct task_struct *t) |
|
{ |
|
WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); |
|
lockdep_assert_held(&t->sighand->siglock); |
|
|
|
task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); |
|
ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
|
} |
|
|
|
/* |
|
* Handle magic process-wide effects of stop/continue signals. Unlike |
|
* the signal actions, these happen immediately at signal-generation |
|
* time regardless of blocking, ignoring, or handling. This does the |
|
* actual continuing for SIGCONT, but not the actual stopping for stop |
|
* signals. The process stop is done as a signal action for SIG_DFL. |
|
* |
|
* Returns true if the signal should be actually delivered, otherwise |
|
* it should be dropped. |
|
*/ |
|
static bool prepare_signal(int sig, struct task_struct *p, bool force) |
|
{ |
|
struct signal_struct *signal = p->signal; |
|
struct task_struct *t; |
|
sigset_t flush; |
|
|
|
if (signal->flags & SIGNAL_GROUP_EXIT) { |
|
if (signal->core_state) |
|
return sig == SIGKILL; |
|
/* |
|
* The process is in the middle of dying, drop the signal. |
|
*/ |
|
return false; |
|
} else if (sig_kernel_stop(sig)) { |
|
/* |
|
* This is a stop signal. Remove SIGCONT from all queues. |
|
*/ |
|
siginitset(&flush, sigmask(SIGCONT)); |
|
flush_sigqueue_mask(&flush, &signal->shared_pending); |
|
for_each_thread(p, t) |
|
flush_sigqueue_mask(&flush, &t->pending); |
|
} else if (sig == SIGCONT) { |
|
unsigned int why; |
|
/* |
|
* Remove all stop signals from all queues, wake all threads. |
|
*/ |
|
siginitset(&flush, SIG_KERNEL_STOP_MASK); |
|
flush_sigqueue_mask(&flush, &signal->shared_pending); |
|
for_each_thread(p, t) { |
|
flush_sigqueue_mask(&flush, &t->pending); |
|
task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
|
if (likely(!(t->ptrace & PT_SEIZED))) { |
|
t->jobctl &= ~JOBCTL_STOPPED; |
|
wake_up_state(t, __TASK_STOPPED); |
|
} else |
|
ptrace_trap_notify(t); |
|
} |
|
|
|
/* |
|
* Notify the parent with CLD_CONTINUED if we were stopped. |
|
* |
|
* If we were in the middle of a group stop, we pretend it |
|
* was already finished, and then continued. Since SIGCHLD |
|
* doesn't queue we report only CLD_STOPPED, as if the next |
|
* CLD_CONTINUED was dropped. |
|
*/ |
|
why = 0; |
|
if (signal->flags & SIGNAL_STOP_STOPPED) |
|
why |= SIGNAL_CLD_CONTINUED; |
|
else if (signal->group_stop_count) |
|
why |= SIGNAL_CLD_STOPPED; |
|
|
|
if (why) { |
|
/* |
|
* The first thread which returns from do_signal_stop() |
|
* will take ->siglock, notice SIGNAL_CLD_MASK, and |
|
* notify its parent. See get_signal(). |
|
*/ |
|
signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED); |
|
signal->group_stop_count = 0; |
|
signal->group_exit_code = 0; |
|
} |
|
} |
|
|
|
return !sig_ignored(p, sig, force); |
|
} |
|
|
|
/* |
|
* Test if P wants to take SIG. After we've checked all threads with this, |
|
* it's equivalent to finding no threads not blocking SIG. Any threads not |
|
* blocking SIG were ruled out because they are not running and already |
|
* have pending signals. Such threads will dequeue from the shared queue |
|
* as soon as they're available, so putting the signal on the shared queue |
|
* will be equivalent to sending it to one such thread. |
|
*/ |
|
static inline bool wants_signal(int sig, struct task_struct *p) |
|
{ |
|
if (sigismember(&p->blocked, sig)) |
|
return false; |
|
|
|
if (p->flags & PF_EXITING) |
|
return false; |
|
|
|
if (sig == SIGKILL) |
|
return true; |
|
|
|
if (task_is_stopped_or_traced(p)) |
|
return false; |
|
|
|
return task_curr(p) || !task_sigpending(p); |
|
} |
|
|
|
static void complete_signal(int sig, struct task_struct *p, enum pid_type type) |
|
{ |
|
struct signal_struct *signal = p->signal; |
|
struct task_struct *t; |
|
|
|
/* |
|
* Now find a thread we can wake up to take the signal off the queue. |
|
* |
|
* If the main thread wants the signal, it gets first crack. |
|
* Probably the least surprising to the average bear. |
|
*/ |
|
if (wants_signal(sig, p)) |
|
t = p; |
|
else if ((type == PIDTYPE_PID) || thread_group_empty(p)) |
|
/* |
|
* There is just one thread and it does not need to be woken. |
|
* It will dequeue unblocked signals before it runs again. |
|
*/ |
|
return; |
|
else { |
|
/* |
|
* Otherwise try to find a suitable thread. |
|
*/ |
|
t = signal->curr_target; |
|
while (!wants_signal(sig, t)) { |
|
t = next_thread(t); |
|
if (t == signal->curr_target) |
|
/* |
|
* No thread needs to be woken. |
|
* Any eligible threads will see |
|
* the signal in the queue soon. |
|
*/ |
|
return; |
|
} |
|
signal->curr_target = t; |
|
} |
|
|
|
/* |
|
* Found a killable thread. If the signal will be fatal, |
|
* then start taking the whole group down immediately. |
|
*/ |
|
if (sig_fatal(p, sig) && |
|
(signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) && |
|
!sigismember(&t->real_blocked, sig) && |
|
(sig == SIGKILL || !p->ptrace)) { |
|
/* |
|
* This signal will be fatal to the whole group. |
|
*/ |
|
if (!sig_kernel_coredump(sig)) { |
|
/* |
|
* Start a group exit and wake everybody up. |
|
* This way we don't have other threads |
|
* running and doing things after a slower |
|
* thread has the fatal signal pending. |
|
*/ |
|
signal->flags = SIGNAL_GROUP_EXIT; |
|
signal->group_exit_code = sig; |
|
signal->group_stop_count = 0; |
|
t = p; |
|
do { |
|
task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
|
sigaddset(&t->pending.signal, SIGKILL); |
|
signal_wake_up(t, 1); |
|
} while_each_thread(p, t); |
|
return; |
|
} |
|
} |
|
|
|
/* |
|
* The signal is already in the shared-pending queue. |
|
* Tell the chosen thread to wake up and dequeue it. |
|
*/ |
|
signal_wake_up(t, sig == SIGKILL); |
|
return; |
|
} |
|
|
|
static inline bool legacy_queue(struct sigpending *signals, int sig) |
|
{ |
|
return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); |
|
} |
|
|
|
static int __send_signal_locked(int sig, struct kernel_siginfo *info, |
|
struct task_struct *t, enum pid_type type, bool force) |
|
{ |
|
struct sigpending *pending; |
|
struct sigqueue *q; |
|
int override_rlimit; |
|
int ret = 0, result; |
|
|
|
lockdep_assert_held(&t->sighand->siglock); |
|
|
|
result = TRACE_SIGNAL_IGNORED; |
|
if (!prepare_signal(sig, t, force)) |
|
goto ret; |
|
|
|
pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; |
|
/* |
|
* Short-circuit ignored signals and support queuing |
|
* exactly one non-rt signal, so that we can get more |
|
* detailed information about the cause of the signal. |
|
*/ |
|
result = TRACE_SIGNAL_ALREADY_PENDING; |
|
if (legacy_queue(pending, sig)) |
|
goto ret; |
|
|
|
result = TRACE_SIGNAL_DELIVERED; |
|
/* |
|
* Skip useless siginfo allocation for SIGKILL and kernel threads. |
|
*/ |
|
if ((sig == SIGKILL) || (t->flags & PF_KTHREAD)) |
|
goto out_set; |
|
|
|
/* |
|
* Real-time signals must be queued if sent by sigqueue, or |
|
* some other real-time mechanism. It is implementation |
|
* defined whether kill() does so. We attempt to do so, on |
|
* the principle of least surprise, but since kill is not |
|
* allowed to fail with EAGAIN when low on memory we just |
|
* make sure at least one signal gets delivered and don't |
|
* pass on the info struct. |
|
*/ |
|
if (sig < SIGRTMIN) |
|
override_rlimit = (is_si_special(info) || info->si_code >= 0); |
|
else |
|
override_rlimit = 0; |
|
|
|
q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0); |
|
|
|
if (q) { |
|
list_add_tail(&q->list, &pending->list); |
|
switch ((unsigned long) info) { |
|
case (unsigned long) SEND_SIG_NOINFO: |
|
clear_siginfo(&q->info); |
|
q->info.si_signo = sig; |
|
q->info.si_errno = 0; |
|
q->info.si_code = SI_USER; |
|
q->info.si_pid = task_tgid_nr_ns(current, |
|
task_active_pid_ns(t)); |
|
rcu_read_lock(); |
|
q->info.si_uid = |
|
from_kuid_munged(task_cred_xxx(t, user_ns), |
|
current_uid()); |
|
rcu_read_unlock(); |
|
break; |
|
case (unsigned long) SEND_SIG_PRIV: |
|
clear_siginfo(&q->info); |
|
q->info.si_signo = sig; |
|
q->info.si_errno = 0; |
|
q->info.si_code = SI_KERNEL; |
|
q->info.si_pid = 0; |
|
q->info.si_uid = 0; |
|
break; |
|
default: |
|
copy_siginfo(&q->info, info); |
|
break; |
|
} |
|
} else if (!is_si_special(info) && |
|
sig >= SIGRTMIN && info->si_code != SI_USER) { |
|
/* |
|
* Queue overflow, abort. We may abort if the |
|
* signal was rt and sent by user using something |
|
* other than kill(). |
|
*/ |
|
result = TRACE_SIGNAL_OVERFLOW_FAIL; |
|
ret = -EAGAIN; |
|
goto ret; |
|
} else { |
|
/* |
|
* This is a silent loss of information. We still |
|
* send the signal, but the *info bits are lost. |
|
*/ |
|
result = TRACE_SIGNAL_LOSE_INFO; |
|
} |
|
|
|
out_set: |
|
signalfd_notify(t, sig); |
|
sigaddset(&pending->signal, sig); |
|
|
|
/* Let multiprocess signals appear after on-going forks */ |
|
if (type > PIDTYPE_TGID) { |
|
struct multiprocess_signals *delayed; |
|
hlist_for_each_entry(delayed, &t->signal->multiprocess, node) { |
|
sigset_t *signal = &delayed->signal; |
|
/* Can't queue both a stop and a continue signal */ |
|
if (sig == SIGCONT) |
|
sigdelsetmask(signal, SIG_KERNEL_STOP_MASK); |
|
else if (sig_kernel_stop(sig)) |
|
sigdelset(signal, SIGCONT); |
|
sigaddset(signal, sig); |
|
} |
|
} |
|
|
|
complete_signal(sig, t, type); |
|
ret: |
|
trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result); |
|
return ret; |
|
} |
|
|
|
static inline bool has_si_pid_and_uid(struct kernel_siginfo *info) |
|
{ |
|
bool ret = false; |
|
switch (siginfo_layout(info->si_signo, info->si_code)) { |
|
case SIL_KILL: |
|
case SIL_CHLD: |
|
case SIL_RT: |
|
ret = true; |
|
break; |
|
case SIL_TIMER: |
|
case SIL_POLL: |
|
case SIL_FAULT: |
|
case SIL_FAULT_TRAPNO: |
|
case SIL_FAULT_MCEERR: |
|
case SIL_FAULT_BNDERR: |
|
case SIL_FAULT_PKUERR: |
|
case SIL_FAULT_PERF_EVENT: |
|
case SIL_SYS: |
|
ret = false; |
|
break; |
|
} |
|
return ret; |
|
} |
|
|
|
int send_signal_locked(int sig, struct kernel_siginfo *info, |
|
struct task_struct *t, enum pid_type type) |
|
{ |
|
/* Should SIGKILL or SIGSTOP be received by a pid namespace init? */ |
|
bool force = false; |
|
|
|
if (info == SEND_SIG_NOINFO) { |
|
/* Force if sent from an ancestor pid namespace */ |
|
force = !task_pid_nr_ns(current, task_active_pid_ns(t)); |
|
} else if (info == SEND_SIG_PRIV) { |
|
/* Don't ignore kernel generated signals */ |
|
force = true; |
|
} else if (has_si_pid_and_uid(info)) { |
|
/* SIGKILL and SIGSTOP is special or has ids */ |
|
struct user_namespace *t_user_ns; |
|
|
|
rcu_read_lock(); |
|
t_user_ns = task_cred_xxx(t, user_ns); |
|
if (current_user_ns() != t_user_ns) { |
|
kuid_t uid = make_kuid(current_user_ns(), info->si_uid); |
|
info->si_uid = from_kuid_munged(t_user_ns, uid); |
|
} |
|
rcu_read_unlock(); |
|
|
|
/* A kernel generated signal? */ |
|
force = (info->si_code == SI_KERNEL); |
|
|
|
/* From an ancestor pid namespace? */ |
|
if (!task_pid_nr_ns(current, task_active_pid_ns(t))) { |
|
info->si_pid = 0; |
|
force = true; |
|
} |
|
} |
|
return __send_signal_locked(sig, info, t, type, force); |
|
} |
|
|
|
static void print_fatal_signal(int signr) |
|
{ |
|
struct pt_regs *regs = signal_pt_regs(); |
|
pr_info("potentially unexpected fatal signal %d.\n", signr); |
|
|
|
#if defined(__i386__) && !defined(__arch_um__) |
|
pr_info("code at %08lx: ", regs->ip); |
|
{ |
|
int i; |
|
for (i = 0; i < 16; i++) { |
|
unsigned char insn; |
|
|
|
if (get_user(insn, (unsigned char *)(regs->ip + i))) |
|
break; |
|
pr_cont("%02x ", insn); |
|
} |
|
} |
|
pr_cont("\n"); |
|
#endif |
|
preempt_disable(); |
|
show_regs(regs); |
|
preempt_enable(); |
|
} |
|
|
|
static int __init setup_print_fatal_signals(char *str) |
|
{ |
|
get_option (&str, &print_fatal_signals); |
|
|
|
return 1; |
|
} |
|
|
|
__setup("print-fatal-signals=", setup_print_fatal_signals); |
|
|
|
int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p, |
|
enum pid_type type) |
|
{ |
|
unsigned long flags; |
|
int ret = -ESRCH; |
|
|
|
if (lock_task_sighand(p, &flags)) { |
|
ret = send_signal_locked(sig, info, p, type); |
|
unlock_task_sighand(p, &flags); |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
enum sig_handler { |
|
HANDLER_CURRENT, /* If reachable use the current handler */ |
|
HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */ |
|
HANDLER_EXIT, /* Only visible as the process exit code */ |
|
}; |
|
|
|
/* |
|
* Force a signal that the process can't ignore: if necessary |
|
* we unblock the signal and change any SIG_IGN to SIG_DFL. |
|
* |
|
* Note: If we unblock the signal, we always reset it to SIG_DFL, |
|
* since we do not want to have a signal handler that was blocked |
|
* be invoked when user space had explicitly blocked it. |
|
* |
|
* We don't want to have recursive SIGSEGV's etc, for example, |
|
* that is why we also clear SIGNAL_UNKILLABLE. |
|
*/ |
|
static int |
|
force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t, |
|
enum sig_handler handler) |
|
{ |
|
unsigned long int flags; |
|
int ret, blocked, ignored; |
|
struct k_sigaction *action; |
|
int sig = info->si_signo; |
|
|
|
spin_lock_irqsave(&t->sighand->siglock, flags); |
|
action = &t->sighand->action[sig-1]; |
|
ignored = action->sa.sa_handler == SIG_IGN; |
|
blocked = sigismember(&t->blocked, sig); |
|
if (blocked || ignored || (handler != HANDLER_CURRENT)) { |
|
action->sa.sa_handler = SIG_DFL; |
|
if (handler == HANDLER_EXIT) |
|
action->sa.sa_flags |= SA_IMMUTABLE; |
|
if (blocked) { |
|
sigdelset(&t->blocked, sig); |
|
recalc_sigpending_and_wake(t); |
|
} |
|
} |
|
/* |
|
* Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect |
|
* debugging to leave init killable. But HANDLER_EXIT is always fatal. |
|
*/ |
|
if (action->sa.sa_handler == SIG_DFL && |
|
(!t->ptrace || (handler == HANDLER_EXIT))) |
|
t->signal->flags &= ~SIGNAL_UNKILLABLE; |
|
ret = send_signal_locked(sig, info, t, PIDTYPE_PID); |
|
spin_unlock_irqrestore(&t->sighand->siglock, flags); |
|
|
|
return ret; |
|
} |
|
|
|
int force_sig_info(struct kernel_siginfo *info) |
|
{ |
|
return force_sig_info_to_task(info, current, HANDLER_CURRENT); |
|
} |
|
|
|
/* |
|
* Nuke all other threads in the group. |
|
*/ |
|
int zap_other_threads(struct task_struct *p) |
|
{ |
|
struct task_struct *t = p; |
|
int count = 0; |
|
|
|
p->signal->group_stop_count = 0; |
|
|
|
while_each_thread(p, t) { |
|
task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
|
count++; |
|
|
|
/* Don't bother with already dead threads */ |
|
if (t->exit_state) |
|
continue; |
|
sigaddset(&t->pending.signal, SIGKILL); |
|
signal_wake_up(t, 1); |
|
} |
|
|
|
return count; |
|
} |
|
|
|
struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
|
unsigned long *flags) |
|
{ |
|
struct sighand_struct *sighand; |
|
|
|
rcu_read_lock(); |
|
for (;;) { |
|
sighand = rcu_dereference(tsk->sighand); |
|
if (unlikely(sighand == NULL)) |
|
break; |
|
|
|
/* |
|
* This sighand can be already freed and even reused, but |
|
* we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which |
|
* initializes ->siglock: this slab can't go away, it has |
|
* the same object type, ->siglock can't be reinitialized. |
|
* |
|
* We need to ensure that tsk->sighand is still the same |
|
* after we take the lock, we can race with de_thread() or |
|
* __exit_signal(). In the latter case the next iteration |
|
* must see ->sighand == NULL. |
|
*/ |
|
spin_lock_irqsave(&sighand->siglock, *flags); |
|
if (likely(sighand == rcu_access_pointer(tsk->sighand))) |
|
break; |
|
spin_unlock_irqrestore(&sighand->siglock, *flags); |
|
} |
|
rcu_read_unlock(); |
|
|
|
return sighand; |
|
} |
|
|
|
#ifdef CONFIG_LOCKDEP |
|
void lockdep_assert_task_sighand_held(struct task_struct *task) |
|
{ |
|
struct sighand_struct *sighand; |
|
|
|
rcu_read_lock(); |
|
sighand = rcu_dereference(task->sighand); |
|
if (sighand) |
|
lockdep_assert_held(&sighand->siglock); |
|
else |
|
WARN_ON_ONCE(1); |
|
rcu_read_unlock(); |
|
} |
|
#endif |
|
|
|
/* |
|
* send signal info to all the members of a group |
|
*/ |
|
int group_send_sig_info(int sig, struct kernel_siginfo *info, |
|
struct task_struct *p, enum pid_type type) |
|
{ |
|
int ret; |
|
|
|
rcu_read_lock(); |
|
ret = check_kill_permission(sig, info, p); |
|
rcu_read_unlock(); |
|
|
|
if (!ret && sig) |
|
ret = do_send_sig_info(sig, info, p, type); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* __kill_pgrp_info() sends a signal to a process group: this is what the tty |
|
* control characters do (^C, ^Z etc) |
|
* - the caller must hold at least a readlock on tasklist_lock |
|
*/ |
|
int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp) |
|
{ |
|
struct task_struct *p = NULL; |
|
int retval, success; |
|
|
|
success = 0; |
|
retval = -ESRCH; |
|
do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
|
int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID); |
|
success |= !err; |
|
retval = err; |
|
} while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
|
return success ? 0 : retval; |
|
} |
|
|
|
int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) |
|
{ |
|
int error = -ESRCH; |
|
struct task_struct *p; |
|
|
|
for (;;) { |
|
rcu_read_lock(); |
|
p = pid_task(pid, PIDTYPE_PID); |
|
if (p) |
|
error = group_send_sig_info(sig, info, p, PIDTYPE_TGID); |
|
rcu_read_unlock(); |
|
if (likely(!p || error != -ESRCH)) |
|
return error; |
|
|
|
/* |
|
* The task was unhashed in between, try again. If it |
|
* is dead, pid_task() will return NULL, if we race with |
|
* de_thread() it will find the new leader. |
|
*/ |
|
} |
|
} |
|
|
|
static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid) |
|
{ |
|
int error; |
|
rcu_read_lock(); |
|
error = kill_pid_info(sig, info, find_vpid(pid)); |
|
rcu_read_unlock(); |
|
return error; |
|
} |
|
|
|
static inline bool kill_as_cred_perm(const struct cred *cred, |
|
struct task_struct *target) |
|
{ |
|
const struct cred *pcred = __task_cred(target); |
|
|
|
return uid_eq(cred->euid, pcred->suid) || |
|
uid_eq(cred->euid, pcred->uid) || |
|
uid_eq(cred->uid, pcred->suid) || |
|
uid_eq(cred->uid, pcred->uid); |
|
} |
|
|
|
/* |
|
* The usb asyncio usage of siginfo is wrong. The glibc support |
|
* for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT. |
|
* AKA after the generic fields: |
|
* kernel_pid_t si_pid; |
|
* kernel_uid32_t si_uid; |
|
* sigval_t si_value; |
|
* |
|
* Unfortunately when usb generates SI_ASYNCIO it assumes the layout |
|
* after the generic fields is: |
|
* void __user *si_addr; |
|
* |
|
* This is a practical problem when there is a 64bit big endian kernel |
|
* and a 32bit userspace. As the 32bit address will encoded in the low |
|
* 32bits of the pointer. Those low 32bits will be stored at higher |
|
* address than appear in a 32 bit pointer. So userspace will not |
|
* see the address it was expecting for it's completions. |
|
* |
|
* There is nothing in the encoding that can allow |
|
* copy_siginfo_to_user32 to detect this confusion of formats, so |
|
* handle this by requiring the caller of kill_pid_usb_asyncio to |
|
* notice when this situration takes place and to store the 32bit |
|
* pointer in sival_int, instead of sival_addr of the sigval_t addr |
|
* parameter. |
|
*/ |
|
int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, |
|
struct pid *pid, const struct cred *cred) |
|
{ |
|
struct kernel_siginfo info; |
|
struct task_struct *p; |
|
unsigned long flags; |
|
int ret = -EINVAL; |
|
|
|
if (!valid_signal(sig)) |
|
return ret; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = errno; |
|
info.si_code = SI_ASYNCIO; |
|
*((sigval_t *)&info.si_pid) = addr; |
|
|
|
rcu_read_lock(); |
|
p = pid_task(pid, PIDTYPE_PID); |
|
if (!p) { |
|
ret = -ESRCH; |
|
goto out_unlock; |
|
} |
|
if (!kill_as_cred_perm(cred, p)) { |
|
ret = -EPERM; |
|
goto out_unlock; |
|
} |
|
ret = security_task_kill(p, &info, sig, cred); |
|
if (ret) |
|
goto out_unlock; |
|
|
|
if (sig) { |
|
if (lock_task_sighand(p, &flags)) { |
|
ret = __send_signal_locked(sig, &info, p, PIDTYPE_TGID, false); |
|
unlock_task_sighand(p, &flags); |
|
} else |
|
ret = -ESRCH; |
|
} |
|
out_unlock: |
|
rcu_read_unlock(); |
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio); |
|
|
|
/* |
|
* kill_something_info() interprets pid in interesting ways just like kill(2). |
|
* |
|
* POSIX specifies that kill(-1,sig) is unspecified, but what we have |
|
* is probably wrong. Should make it like BSD or SYSV. |
|
*/ |
|
|
|
static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid) |
|
{ |
|
int ret; |
|
|
|
if (pid > 0) |
|
return kill_proc_info(sig, info, pid); |
|
|
|
/* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */ |
|
if (pid == INT_MIN) |
|
return -ESRCH; |
|
|
|
read_lock(&tasklist_lock); |
|
if (pid != -1) { |
|
ret = __kill_pgrp_info(sig, info, |
|
pid ? find_vpid(-pid) : task_pgrp(current)); |
|
} else { |
|
int retval = 0, count = 0; |
|
struct task_struct * p; |
|
|
|
for_each_process(p) { |
|
if (task_pid_vnr(p) > 1 && |
|
!same_thread_group(p, current)) { |
|
int err = group_send_sig_info(sig, info, p, |
|
PIDTYPE_MAX); |
|
++count; |
|
if (err != -EPERM) |
|
retval = err; |
|
} |
|
} |
|
ret = count ? retval : -ESRCH; |
|
} |
|
read_unlock(&tasklist_lock); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* These are for backward compatibility with the rest of the kernel source. |
|
*/ |
|
|
|
int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p) |
|
{ |
|
/* |
|
* Make sure legacy kernel users don't send in bad values |
|
* (normal paths check this in check_kill_permission). |
|
*/ |
|
if (!valid_signal(sig)) |
|
return -EINVAL; |
|
|
|
return do_send_sig_info(sig, info, p, PIDTYPE_PID); |
|
} |
|
EXPORT_SYMBOL(send_sig_info); |
|
|
|
#define __si_special(priv) \ |
|
((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) |
|
|
|
int |
|
send_sig(int sig, struct task_struct *p, int priv) |
|
{ |
|
return send_sig_info(sig, __si_special(priv), p); |
|
} |
|
EXPORT_SYMBOL(send_sig); |
|
|
|
void force_sig(int sig) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
info.si_code = SI_KERNEL; |
|
info.si_pid = 0; |
|
info.si_uid = 0; |
|
force_sig_info(&info); |
|
} |
|
EXPORT_SYMBOL(force_sig); |
|
|
|
void force_fatal_sig(int sig) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
info.si_code = SI_KERNEL; |
|
info.si_pid = 0; |
|
info.si_uid = 0; |
|
force_sig_info_to_task(&info, current, HANDLER_SIG_DFL); |
|
} |
|
|
|
void force_exit_sig(int sig) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
info.si_code = SI_KERNEL; |
|
info.si_pid = 0; |
|
info.si_uid = 0; |
|
force_sig_info_to_task(&info, current, HANDLER_EXIT); |
|
} |
|
|
|
/* |
|
* When things go south during signal handling, we |
|
* will force a SIGSEGV. And if the signal that caused |
|
* the problem was already a SIGSEGV, we'll want to |
|
* make sure we don't even try to deliver the signal.. |
|
*/ |
|
void force_sigsegv(int sig) |
|
{ |
|
if (sig == SIGSEGV) |
|
force_fatal_sig(SIGSEGV); |
|
else |
|
force_sig(SIGSEGV); |
|
} |
|
|
|
int force_sig_fault_to_task(int sig, int code, void __user *addr |
|
___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr) |
|
, struct task_struct *t) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
info.si_code = code; |
|
info.si_addr = addr; |
|
#ifdef __ia64__ |
|
info.si_imm = imm; |
|
info.si_flags = flags; |
|
info.si_isr = isr; |
|
#endif |
|
return force_sig_info_to_task(&info, t, HANDLER_CURRENT); |
|
} |
|
|
|
int force_sig_fault(int sig, int code, void __user *addr |
|
___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)) |
|
{ |
|
return force_sig_fault_to_task(sig, code, addr |
|
___ARCH_SI_IA64(imm, flags, isr), current); |
|
} |
|
|
|
int send_sig_fault(int sig, int code, void __user *addr |
|
___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr) |
|
, struct task_struct *t) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
info.si_code = code; |
|
info.si_addr = addr; |
|
#ifdef __ia64__ |
|
info.si_imm = imm; |
|
info.si_flags = flags; |
|
info.si_isr = isr; |
|
#endif |
|
return send_sig_info(info.si_signo, &info, t); |
|
} |
|
|
|
int force_sig_mceerr(int code, void __user *addr, short lsb) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR)); |
|
clear_siginfo(&info); |
|
info.si_signo = SIGBUS; |
|
info.si_errno = 0; |
|
info.si_code = code; |
|
info.si_addr = addr; |
|
info.si_addr_lsb = lsb; |
|
return force_sig_info(&info); |
|
} |
|
|
|
int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR)); |
|
clear_siginfo(&info); |
|
info.si_signo = SIGBUS; |
|
info.si_errno = 0; |
|
info.si_code = code; |
|
info.si_addr = addr; |
|
info.si_addr_lsb = lsb; |
|
return send_sig_info(info.si_signo, &info, t); |
|
} |
|
EXPORT_SYMBOL(send_sig_mceerr); |
|
|
|
int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = SIGSEGV; |
|
info.si_errno = 0; |
|
info.si_code = SEGV_BNDERR; |
|
info.si_addr = addr; |
|
info.si_lower = lower; |
|
info.si_upper = upper; |
|
return force_sig_info(&info); |
|
} |
|
|
|
#ifdef SEGV_PKUERR |
|
int force_sig_pkuerr(void __user *addr, u32 pkey) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = SIGSEGV; |
|
info.si_errno = 0; |
|
info.si_code = SEGV_PKUERR; |
|
info.si_addr = addr; |
|
info.si_pkey = pkey; |
|
return force_sig_info(&info); |
|
} |
|
#endif |
|
|
|
int send_sig_perf(void __user *addr, u32 type, u64 sig_data) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = SIGTRAP; |
|
info.si_errno = 0; |
|
info.si_code = TRAP_PERF; |
|
info.si_addr = addr; |
|
info.si_perf_data = sig_data; |
|
info.si_perf_type = type; |
|
|
|
/* |
|
* Signals generated by perf events should not terminate the whole |
|
* process if SIGTRAP is blocked, however, delivering the signal |
|
* asynchronously is better than not delivering at all. But tell user |
|
* space if the signal was asynchronous, so it can clearly be |
|
* distinguished from normal synchronous ones. |
|
*/ |
|
info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ? |
|
TRAP_PERF_FLAG_ASYNC : |
|
0; |
|
|
|
return send_sig_info(info.si_signo, &info, current); |
|
} |
|
|
|
/** |
|
* force_sig_seccomp - signals the task to allow in-process syscall emulation |
|
* @syscall: syscall number to send to userland |
|
* @reason: filter-supplied reason code to send to userland (via si_errno) |
|
* @force_coredump: true to trigger a coredump |
|
* |
|
* Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info. |
|
*/ |
|
int force_sig_seccomp(int syscall, int reason, bool force_coredump) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = SIGSYS; |
|
info.si_code = SYS_SECCOMP; |
|
info.si_call_addr = (void __user *)KSTK_EIP(current); |
|
info.si_errno = reason; |
|
info.si_arch = syscall_get_arch(current); |
|
info.si_syscall = syscall; |
|
return force_sig_info_to_task(&info, current, |
|
force_coredump ? HANDLER_EXIT : HANDLER_CURRENT); |
|
} |
|
|
|
/* For the crazy architectures that include trap information in |
|
* the errno field, instead of an actual errno value. |
|
*/ |
|
int force_sig_ptrace_errno_trap(int errno, void __user *addr) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = SIGTRAP; |
|
info.si_errno = errno; |
|
info.si_code = TRAP_HWBKPT; |
|
info.si_addr = addr; |
|
return force_sig_info(&info); |
|
} |
|
|
|
/* For the rare architectures that include trap information using |
|
* si_trapno. |
|
*/ |
|
int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
info.si_code = code; |
|
info.si_addr = addr; |
|
info.si_trapno = trapno; |
|
return force_sig_info(&info); |
|
} |
|
|
|
/* For the rare architectures that include trap information using |
|
* si_trapno. |
|
*/ |
|
int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno, |
|
struct task_struct *t) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
info.si_code = code; |
|
info.si_addr = addr; |
|
info.si_trapno = trapno; |
|
return send_sig_info(info.si_signo, &info, t); |
|
} |
|
|
|
int kill_pgrp(struct pid *pid, int sig, int priv) |
|
{ |
|
int ret; |
|
|
|
read_lock(&tasklist_lock); |
|
ret = __kill_pgrp_info(sig, __si_special(priv), pid); |
|
read_unlock(&tasklist_lock); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(kill_pgrp); |
|
|
|
int kill_pid(struct pid *pid, int sig, int priv) |
|
{ |
|
return kill_pid_info(sig, __si_special(priv), pid); |
|
} |
|
EXPORT_SYMBOL(kill_pid); |
|
|
|
/* |
|
* These functions support sending signals using preallocated sigqueue |
|
* structures. This is needed "because realtime applications cannot |
|
* afford to lose notifications of asynchronous events, like timer |
|
* expirations or I/O completions". In the case of POSIX Timers |
|
* we allocate the sigqueue structure from the timer_create. If this |
|
* allocation fails we are able to report the failure to the application |
|
* with an EAGAIN error. |
|
*/ |
|
struct sigqueue *sigqueue_alloc(void) |
|
{ |
|
return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC); |
|
} |
|
|
|
void sigqueue_free(struct sigqueue *q) |
|
{ |
|
unsigned long flags; |
|
spinlock_t *lock = ¤t->sighand->siglock; |
|
|
|
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
|
/* |
|
* We must hold ->siglock while testing q->list |
|
* to serialize with collect_signal() or with |
|
* __exit_signal()->flush_sigqueue(). |
|
*/ |
|
spin_lock_irqsave(lock, flags); |
|
q->flags &= ~SIGQUEUE_PREALLOC; |
|
/* |
|
* If it is queued it will be freed when dequeued, |
|
* like the "regular" sigqueue. |
|
*/ |
|
if (!list_empty(&q->list)) |
|
q = NULL; |
|
spin_unlock_irqrestore(lock, flags); |
|
|
|
if (q) |
|
__sigqueue_free(q); |
|
} |
|
|
|
int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type) |
|
{ |
|
int sig = q->info.si_signo; |
|
struct sigpending *pending; |
|
struct task_struct *t; |
|
unsigned long flags; |
|
int ret, result; |
|
|
|
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
|
|
|
ret = -1; |
|
rcu_read_lock(); |
|
t = pid_task(pid, type); |
|
if (!t || !likely(lock_task_sighand(t, &flags))) |
|
goto ret; |
|
|
|
ret = 1; /* the signal is ignored */ |
|
result = TRACE_SIGNAL_IGNORED; |
|
if (!prepare_signal(sig, t, false)) |
|
goto out; |
|
|
|
ret = 0; |
|
if (unlikely(!list_empty(&q->list))) { |
|
/* |
|
* If an SI_TIMER entry is already queue just increment |
|
* the overrun count. |
|
*/ |
|
BUG_ON(q->info.si_code != SI_TIMER); |
|
q->info.si_overrun++; |
|
result = TRACE_SIGNAL_ALREADY_PENDING; |
|
goto out; |
|
} |
|
q->info.si_overrun = 0; |
|
|
|
signalfd_notify(t, sig); |
|
pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; |
|
list_add_tail(&q->list, &pending->list); |
|
sigaddset(&pending->signal, sig); |
|
complete_signal(sig, t, type); |
|
result = TRACE_SIGNAL_DELIVERED; |
|
out: |
|
trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result); |
|
unlock_task_sighand(t, &flags); |
|
ret: |
|
rcu_read_unlock(); |
|
return ret; |
|
} |
|
|
|
static void do_notify_pidfd(struct task_struct *task) |
|
{ |
|
struct pid *pid; |
|
|
|
WARN_ON(task->exit_state == 0); |
|
pid = task_pid(task); |
|
wake_up_all(&pid->wait_pidfd); |
|
} |
|
|
|
/* |
|
* Let a parent know about the death of a child. |
|
* For a stopped/continued status change, use do_notify_parent_cldstop instead. |
|
* |
|
* Returns true if our parent ignored us and so we've switched to |
|
* self-reaping. |
|
*/ |
|
bool do_notify_parent(struct task_struct *tsk, int sig) |
|
{ |
|
struct kernel_siginfo info; |
|
unsigned long flags; |
|
struct sighand_struct *psig; |
|
bool autoreap = false; |
|
u64 utime, stime; |
|
|
|
WARN_ON_ONCE(sig == -1); |
|
|
|
/* do_notify_parent_cldstop should have been called instead. */ |
|
WARN_ON_ONCE(task_is_stopped_or_traced(tsk)); |
|
|
|
WARN_ON_ONCE(!tsk->ptrace && |
|
(tsk->group_leader != tsk || !thread_group_empty(tsk))); |
|
|
|
/* Wake up all pidfd waiters */ |
|
do_notify_pidfd(tsk); |
|
|
|
if (sig != SIGCHLD) { |
|
/* |
|
* This is only possible if parent == real_parent. |
|
* Check if it has changed security domain. |
|
*/ |
|
if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id)) |
|
sig = SIGCHLD; |
|
} |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
/* |
|
* We are under tasklist_lock here so our parent is tied to |
|
* us and cannot change. |
|
* |
|
* task_active_pid_ns will always return the same pid namespace |
|
* until a task passes through release_task. |
|
* |
|
* write_lock() currently calls preempt_disable() which is the |
|
* same as rcu_read_lock(), but according to Oleg, this is not |
|
* correct to rely on this |
|
*/ |
|
rcu_read_lock(); |
|
info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
|
info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
|
task_uid(tsk)); |
|
rcu_read_unlock(); |
|
|
|
task_cputime(tsk, &utime, &stime); |
|
info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime); |
|
info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime); |
|
|
|
info.si_status = tsk->exit_code & 0x7f; |
|
if (tsk->exit_code & 0x80) |
|
info.si_code = CLD_DUMPED; |
|
else if (tsk->exit_code & 0x7f) |
|
info.si_code = CLD_KILLED; |
|
else { |
|
info.si_code = CLD_EXITED; |
|
info.si_status = tsk->exit_code >> 8; |
|
} |
|
|
|
psig = tsk->parent->sighand; |
|
spin_lock_irqsave(&psig->siglock, flags); |
|
if (!tsk->ptrace && sig == SIGCHLD && |
|
(psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
|
(psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { |
|
/* |
|
* We are exiting and our parent doesn't care. POSIX.1 |
|
* defines special semantics for setting SIGCHLD to SIG_IGN |
|
* or setting the SA_NOCLDWAIT flag: we should be reaped |
|
* automatically and not left for our parent's wait4 call. |
|
* Rather than having the parent do it as a magic kind of |
|
* signal handler, we just set this to tell do_exit that we |
|
* can be cleaned up without becoming a zombie. Note that |
|
* we still call __wake_up_parent in this case, because a |
|
* blocked sys_wait4 might now return -ECHILD. |
|
* |
|
* Whether we send SIGCHLD or not for SA_NOCLDWAIT |
|
* is implementation-defined: we do (if you don't want |
|
* it, just use SIG_IGN instead). |
|
*/ |
|
autoreap = true; |
|
if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
|
sig = 0; |
|
} |
|
/* |
|
* Send with __send_signal as si_pid and si_uid are in the |
|
* parent's namespaces. |
|
*/ |
|
if (valid_signal(sig) && sig) |
|
__send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false); |
|
__wake_up_parent(tsk, tsk->parent); |
|
spin_unlock_irqrestore(&psig->siglock, flags); |
|
|
|
return autoreap; |
|
} |
|
|
|
/** |
|
* do_notify_parent_cldstop - notify parent of stopped/continued state change |
|
* @tsk: task reporting the state change |
|
* @for_ptracer: the notification is for ptracer |
|
* @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report |
|
* |
|
* Notify @tsk's parent that the stopped/continued state has changed. If |
|
* @for_ptracer is %false, @tsk's group leader notifies to its real parent. |
|
* If %true, @tsk reports to @tsk->parent which should be the ptracer. |
|
* |
|
* CONTEXT: |
|
* Must be called with tasklist_lock at least read locked. |
|
*/ |
|
static void do_notify_parent_cldstop(struct task_struct *tsk, |
|
bool for_ptracer, int why) |
|
{ |
|
struct kernel_siginfo info; |
|
unsigned long flags; |
|
struct task_struct *parent; |
|
struct sighand_struct *sighand; |
|
u64 utime, stime; |
|
|
|
if (for_ptracer) { |
|
parent = tsk->parent; |
|
} else { |
|
tsk = tsk->group_leader; |
|
parent = tsk->real_parent; |
|
} |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = SIGCHLD; |
|
info.si_errno = 0; |
|
/* |
|
* see comment in do_notify_parent() about the following 4 lines |
|
*/ |
|
rcu_read_lock(); |
|
info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
|
info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
|
rcu_read_unlock(); |
|
|
|
task_cputime(tsk, &utime, &stime); |
|
info.si_utime = nsec_to_clock_t(utime); |
|
info.si_stime = nsec_to_clock_t(stime); |
|
|
|
info.si_code = why; |
|
switch (why) { |
|
case CLD_CONTINUED: |
|
info.si_status = SIGCONT; |
|
break; |
|
case CLD_STOPPED: |
|
info.si_status = tsk->signal->group_exit_code & 0x7f; |
|
break; |
|
case CLD_TRAPPED: |
|
info.si_status = tsk->exit_code & 0x7f; |
|
break; |
|
default: |
|
BUG(); |
|
} |
|
|
|
sighand = parent->sighand; |
|
spin_lock_irqsave(&sighand->siglock, flags); |
|
if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && |
|
!(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) |
|
send_signal_locked(SIGCHLD, &info, parent, PIDTYPE_TGID); |
|
/* |
|
* Even if SIGCHLD is not generated, we must wake up wait4 calls. |
|
*/ |
|
__wake_up_parent(tsk, parent); |
|
spin_unlock_irqrestore(&sighand->siglock, flags); |
|
} |
|
|
|
/* |
|
* This must be called with current->sighand->siglock held. |
|
* |
|
* This should be the path for all ptrace stops. |
|
* We always set current->last_siginfo while stopped here. |
|
* That makes it a way to test a stopped process for |
|
* being ptrace-stopped vs being job-control-stopped. |
|
* |
|
* Returns the signal the ptracer requested the code resume |
|
* with. If the code did not stop because the tracer is gone, |
|
* the stop signal remains unchanged unless clear_code. |
|
*/ |
|
static int ptrace_stop(int exit_code, int why, unsigned long message, |
|
kernel_siginfo_t *info) |
|
__releases(¤t->sighand->siglock) |
|
__acquires(¤t->sighand->siglock) |
|
{ |
|
bool gstop_done = false; |
|
|
|
if (arch_ptrace_stop_needed()) { |
|
/* |
|
* The arch code has something special to do before a |
|
* ptrace stop. This is allowed to block, e.g. for faults |
|
* on user stack pages. We can't keep the siglock while |
|
* calling arch_ptrace_stop, so we must release it now. |
|
* To preserve proper semantics, we must do this before |
|
* any signal bookkeeping like checking group_stop_count. |
|
*/ |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
arch_ptrace_stop(); |
|
spin_lock_irq(¤t->sighand->siglock); |
|
} |
|
|
|
/* |
|
* After this point ptrace_signal_wake_up or signal_wake_up |
|
* will clear TASK_TRACED if ptrace_unlink happens or a fatal |
|
* signal comes in. Handle previous ptrace_unlinks and fatal |
|
* signals here to prevent ptrace_stop sleeping in schedule. |
|
*/ |
|
if (!current->ptrace || __fatal_signal_pending(current)) |
|
return exit_code; |
|
|
|
set_special_state(TASK_TRACED); |
|
current->jobctl |= JOBCTL_TRACED; |
|
|
|
/* |
|
* We're committing to trapping. TRACED should be visible before |
|
* TRAPPING is cleared; otherwise, the tracer might fail do_wait(). |
|
* Also, transition to TRACED and updates to ->jobctl should be |
|
* atomic with respect to siglock and should be done after the arch |
|
* hook as siglock is released and regrabbed across it. |
|
* |
|
* TRACER TRACEE |
|
* |
|
* ptrace_attach() |
|
* [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED) |
|
* do_wait() |
|
* set_current_state() smp_wmb(); |
|
* ptrace_do_wait() |
|
* wait_task_stopped() |
|
* task_stopped_code() |
|
* [L] task_is_traced() [S] task_clear_jobctl_trapping(); |
|
*/ |
|
smp_wmb(); |
|
|
|
current->ptrace_message = message; |
|
current->last_siginfo = info; |
|
current->exit_code = exit_code; |
|
|
|
/* |
|
* If @why is CLD_STOPPED, we're trapping to participate in a group |
|
* stop. Do the bookkeeping. Note that if SIGCONT was delievered |
|
* across siglock relocks since INTERRUPT was scheduled, PENDING |
|
* could be clear now. We act as if SIGCONT is received after |
|
* TASK_TRACED is entered - ignore it. |
|
*/ |
|
if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
|
gstop_done = task_participate_group_stop(current); |
|
|
|
/* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
|
task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
|
if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
|
task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); |
|
|
|
/* entering a trap, clear TRAPPING */ |
|
task_clear_jobctl_trapping(current); |
|
|
|
spin_unlock_irq(¤t->sighand->siglock); |
|
read_lock(&tasklist_lock); |
|
/* |
|
* Notify parents of the stop. |
|
* |
|
* While ptraced, there are two parents - the ptracer and |
|
* the real_parent of the group_leader. The ptracer should |
|
* know about every stop while the real parent is only |
|
* interested in the completion of group stop. The states |
|
* for the two don't interact with each other. Notify |
|
* separately unless they're gonna be duplicates. |
|
*/ |
|
if (current->ptrace) |
|
do_notify_parent_cldstop(current, true, why); |
|
if (gstop_done && (!current->ptrace || ptrace_reparented(current))) |
|
do_notify_parent_cldstop(current, false, why); |
|
|
|
/* |
|
* Don't want to allow preemption here, because |
|
* sys_ptrace() needs this task to be inactive. |
|
* |
|
* XXX: implement read_unlock_no_resched(). |
|
*/ |
|
preempt_disable(); |
|
read_unlock(&tasklist_lock); |
|
cgroup_enter_frozen(); |
|
preempt_enable_no_resched(); |
|
schedule(); |
|
cgroup_leave_frozen(true); |
|
|
|
/* |
|
* We are back. Now reacquire the siglock before touching |
|
* last_siginfo, so that we are sure to have synchronized with |
|
* any signal-sending on another CPU that wants to examine it. |
|
*/ |
|
spin_lock_irq(¤t->sighand->siglock); |
|
exit_code = current->exit_code; |
|
current->last_siginfo = NULL; |
|
current->ptrace_message = 0; |
|
current->exit_code = 0; |
|
|
|
/* LISTENING can be set only during STOP traps, clear it */ |
|
current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN); |
|
|
|
/* |
|
* Queued signals ignored us while we were stopped for tracing. |
|
* So check for any that we should take before resuming user mode. |
|
* This sets TIF_SIGPENDING, but never clears it. |
|
*/ |
|
recalc_sigpending_tsk(current); |
|
return exit_code; |
|
} |
|
|
|
static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message) |
|
{ |
|
kernel_siginfo_t info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = signr; |
|
info.si_code = exit_code; |
|
info.si_pid = task_pid_vnr(current); |
|
info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
|
|
|
/* Let the debugger run. */ |
|
return ptrace_stop(exit_code, why, message, &info); |
|
} |
|
|
|
int ptrace_notify(int exit_code, unsigned long message) |
|
{ |
|
int signr; |
|
|
|
BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); |
|
if (unlikely(task_work_pending(current))) |
|
task_work_run(); |
|
|
|
spin_lock_irq(¤t->sighand->siglock); |
|
signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message); |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
return signr; |
|
} |
|
|
|
/** |
|
* do_signal_stop - handle group stop for SIGSTOP and other stop signals |
|
* @signr: signr causing group stop if initiating |
|
* |
|
* If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr |
|
* and participate in it. If already set, participate in the existing |
|
* group stop. If participated in a group stop (and thus slept), %true is |
|
* returned with siglock released. |
|
* |
|
* If ptraced, this function doesn't handle stop itself. Instead, |
|
* %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock |
|
* untouched. The caller must ensure that INTERRUPT trap handling takes |
|
* places afterwards. |
|
* |
|
* CONTEXT: |
|
* Must be called with @current->sighand->siglock held, which is released |
|
* on %true return. |
|
* |
|
* RETURNS: |
|
* %false if group stop is already cancelled or ptrace trap is scheduled. |
|
* %true if participated in group stop. |
|
*/ |
|
static bool do_signal_stop(int signr) |
|
__releases(¤t->sighand->siglock) |
|
{ |
|
struct signal_struct *sig = current->signal; |
|
|
|
if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
|
unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
|
struct task_struct *t; |
|
|
|
/* signr will be recorded in task->jobctl for retries */ |
|
WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); |
|
|
|
if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
|
unlikely(sig->flags & SIGNAL_GROUP_EXIT) || |
|
unlikely(sig->group_exec_task)) |
|
return false; |
|
/* |
|
* There is no group stop already in progress. We must |
|
* initiate one now. |
|
* |
|
* While ptraced, a task may be resumed while group stop is |
|
* still in effect and then receive a stop signal and |
|
* initiate another group stop. This deviates from the |
|
* usual behavior as two consecutive stop signals can't |
|
* cause two group stops when !ptraced. That is why we |
|
* also check !task_is_stopped(t) below. |
|
* |
|
* The condition can be distinguished by testing whether |
|
* SIGNAL_STOP_STOPPED is already set. Don't generate |
|
* group_exit_code in such case. |
|
* |
|
* This is not necessary for SIGNAL_STOP_CONTINUED because |
|
* an intervening stop signal is required to cause two |
|
* continued events regardless of ptrace. |
|
*/ |
|
if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
|
sig->group_exit_code = signr; |
|
|
|
sig->group_stop_count = 0; |
|
|
|
if (task_set_jobctl_pending(current, signr | gstop)) |
|
sig->group_stop_count++; |
|
|
|
t = current; |
|
while_each_thread(current, t) { |
|
/* |
|
* Setting state to TASK_STOPPED for a group |
|
* stop is always done with the siglock held, |
|
* so this check has no races. |
|
*/ |
|
if (!task_is_stopped(t) && |
|
task_set_jobctl_pending(t, signr | gstop)) { |
|
sig->group_stop_count++; |
|
if (likely(!(t->ptrace & PT_SEIZED))) |
|
signal_wake_up(t, 0); |
|
else |
|
ptrace_trap_notify(t); |
|
} |
|
} |
|
} |
|
|
|
if (likely(!current->ptrace)) { |
|
int notify = 0; |
|
|
|
/* |
|
* If there are no other threads in the group, or if there |
|
* is a group stop in progress and we are the last to stop, |
|
* report to the parent. |
|
*/ |
|
if (task_participate_group_stop(current)) |
|
notify = CLD_STOPPED; |
|
|
|
current->jobctl |= JOBCTL_STOPPED; |
|
set_special_state(TASK_STOPPED); |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
|
|
/* |
|
* Notify the parent of the group stop completion. Because |
|
* we're not holding either the siglock or tasklist_lock |
|
* here, ptracer may attach inbetween; however, this is for |
|
* group stop and should always be delivered to the real |
|
* parent of the group leader. The new ptracer will get |
|
* its notification when this task transitions into |
|
* TASK_TRACED. |
|
*/ |
|
if (notify) { |
|
read_lock(&tasklist_lock); |
|
do_notify_parent_cldstop(current, false, notify); |
|
read_unlock(&tasklist_lock); |
|
} |
|
|
|
/* Now we don't run again until woken by SIGCONT or SIGKILL */ |
|
cgroup_enter_frozen(); |
|
schedule(); |
|
return true; |
|
} else { |
|
/* |
|
* While ptraced, group stop is handled by STOP trap. |
|
* Schedule it and let the caller deal with it. |
|
*/ |
|
task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); |
|
return false; |
|
} |
|
} |
|
|
|
/** |
|
* do_jobctl_trap - take care of ptrace jobctl traps |
|
* |
|
* When PT_SEIZED, it's used for both group stop and explicit |
|
* SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with |
|
* accompanying siginfo. If stopped, lower eight bits of exit_code contain |
|
* the stop signal; otherwise, %SIGTRAP. |
|
* |
|
* When !PT_SEIZED, it's used only for group stop trap with stop signal |
|
* number as exit_code and no siginfo. |
|
* |
|
* CONTEXT: |
|
* Must be called with @current->sighand->siglock held, which may be |
|
* released and re-acquired before returning with intervening sleep. |
|
*/ |
|
static void do_jobctl_trap(void) |
|
{ |
|
struct signal_struct *signal = current->signal; |
|
int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
|
|
|
if (current->ptrace & PT_SEIZED) { |
|
if (!signal->group_stop_count && |
|
!(signal->flags & SIGNAL_STOP_STOPPED)) |
|
signr = SIGTRAP; |
|
WARN_ON_ONCE(!signr); |
|
ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), |
|
CLD_STOPPED, 0); |
|
} else { |
|
WARN_ON_ONCE(!signr); |
|
ptrace_stop(signr, CLD_STOPPED, 0, NULL); |
|
} |
|
} |
|
|
|
/** |
|
* do_freezer_trap - handle the freezer jobctl trap |
|
* |
|
* Puts the task into frozen state, if only the task is not about to quit. |
|
* In this case it drops JOBCTL_TRAP_FREEZE. |
|
* |
|
* CONTEXT: |
|
* Must be called with @current->sighand->siglock held, |
|
* which is always released before returning. |
|
*/ |
|
static void do_freezer_trap(void) |
|
__releases(¤t->sighand->siglock) |
|
{ |
|
/* |
|
* If there are other trap bits pending except JOBCTL_TRAP_FREEZE, |
|
* let's make another loop to give it a chance to be handled. |
|
* In any case, we'll return back. |
|
*/ |
|
if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) != |
|
JOBCTL_TRAP_FREEZE) { |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
return; |
|
} |
|
|
|
/* |
|
* Now we're sure that there is no pending fatal signal and no |
|
* pending traps. Clear TIF_SIGPENDING to not get out of schedule() |
|
* immediately (if there is a non-fatal signal pending), and |
|
* put the task into sleep. |
|
*/ |
|
__set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE); |
|
clear_thread_flag(TIF_SIGPENDING); |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
cgroup_enter_frozen(); |
|
schedule(); |
|
} |
|
|
|
static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type) |
|
{ |
|
/* |
|
* We do not check sig_kernel_stop(signr) but set this marker |
|
* unconditionally because we do not know whether debugger will |
|
* change signr. This flag has no meaning unless we are going |
|
* to stop after return from ptrace_stop(). In this case it will |
|
* be checked in do_signal_stop(), we should only stop if it was |
|
* not cleared by SIGCONT while we were sleeping. See also the |
|
* comment in dequeue_signal(). |
|
*/ |
|
current->jobctl |= JOBCTL_STOP_DEQUEUED; |
|
signr = ptrace_stop(signr, CLD_TRAPPED, 0, info); |
|
|
|
/* We're back. Did the debugger cancel the sig? */ |
|
if (signr == 0) |
|
return signr; |
|
|
|
/* |
|
* Update the siginfo structure if the signal has |
|
* changed. If the debugger wanted something |
|
* specific in the siginfo structure then it should |
|
* have updated *info via PTRACE_SETSIGINFO. |
|
*/ |
|
if (signr != info->si_signo) { |
|
clear_siginfo(info); |
|
info->si_signo = signr; |
|
info->si_errno = 0; |
|
info->si_code = SI_USER; |
|
rcu_read_lock(); |
|
info->si_pid = task_pid_vnr(current->parent); |
|
info->si_uid = from_kuid_munged(current_user_ns(), |
|
task_uid(current->parent)); |
|
rcu_read_unlock(); |
|
} |
|
|
|
/* If the (new) signal is now blocked, requeue it. */ |
|
if (sigismember(¤t->blocked, signr) || |
|
fatal_signal_pending(current)) { |
|
send_signal_locked(signr, info, current, type); |
|
signr = 0; |
|
} |
|
|
|
return signr; |
|
} |
|
|
|
static void hide_si_addr_tag_bits(struct ksignal *ksig) |
|
{ |
|
switch (siginfo_layout(ksig->sig, ksig->info.si_code)) { |
|
case SIL_FAULT: |
|
case SIL_FAULT_TRAPNO: |
|
case SIL_FAULT_MCEERR: |
|
case SIL_FAULT_BNDERR: |
|
case SIL_FAULT_PKUERR: |
|
case SIL_FAULT_PERF_EVENT: |
|
ksig->info.si_addr = arch_untagged_si_addr( |
|
ksig->info.si_addr, ksig->sig, ksig->info.si_code); |
|
break; |
|
case SIL_KILL: |
|
case SIL_TIMER: |
|
case SIL_POLL: |
|
case SIL_CHLD: |
|
case SIL_RT: |
|
case SIL_SYS: |
|
break; |
|
} |
|
} |
|
|
|
bool get_signal(struct ksignal *ksig) |
|
{ |
|
struct sighand_struct *sighand = current->sighand; |
|
struct signal_struct *signal = current->signal; |
|
int signr; |
|
|
|
clear_notify_signal(); |
|
if (unlikely(task_work_pending(current))) |
|
task_work_run(); |
|
|
|
if (!task_sigpending(current)) |
|
return false; |
|
|
|
if (unlikely(uprobe_deny_signal())) |
|
return false; |
|
|
|
/* |
|
* Do this once, we can't return to user-mode if freezing() == T. |
|
* do_signal_stop() and ptrace_stop() do freezable_schedule() and |
|
* thus do not need another check after return. |
|
*/ |
|
try_to_freeze(); |
|
|
|
relock: |
|
spin_lock_irq(&sighand->siglock); |
|
|
|
/* |
|
* Every stopped thread goes here after wakeup. Check to see if |
|
* we should notify the parent, prepare_signal(SIGCONT) encodes |
|
* the CLD_ si_code into SIGNAL_CLD_MASK bits. |
|
*/ |
|
if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
|
int why; |
|
|
|
if (signal->flags & SIGNAL_CLD_CONTINUED) |
|
why = CLD_CONTINUED; |
|
else |
|
why = CLD_STOPPED; |
|
|
|
signal->flags &= ~SIGNAL_CLD_MASK; |
|
|
|
spin_unlock_irq(&sighand->siglock); |
|
|
|
/* |
|
* Notify the parent that we're continuing. This event is |
|
* always per-process and doesn't make whole lot of sense |
|
* for ptracers, who shouldn't consume the state via |
|
* wait(2) either, but, for backward compatibility, notify |
|
* the ptracer of the group leader too unless it's gonna be |
|
* a duplicate. |
|
*/ |
|
read_lock(&tasklist_lock); |
|
do_notify_parent_cldstop(current, false, why); |
|
|
|
if (ptrace_reparented(current->group_leader)) |
|
do_notify_parent_cldstop(current->group_leader, |
|
true, why); |
|
read_unlock(&tasklist_lock); |
|
|
|
goto relock; |
|
} |
|
|
|
for (;;) { |
|
struct k_sigaction *ka; |
|
enum pid_type type; |
|
|
|
/* Has this task already been marked for death? */ |
|
if ((signal->flags & SIGNAL_GROUP_EXIT) || |
|
signal->group_exec_task) { |
|
ksig->info.si_signo = signr = SIGKILL; |
|
sigdelset(¤t->pending.signal, SIGKILL); |
|
trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, |
|
&sighand->action[SIGKILL - 1]); |
|
recalc_sigpending(); |
|
goto fatal; |
|
} |
|
|
|
if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
|
do_signal_stop(0)) |
|
goto relock; |
|
|
|
if (unlikely(current->jobctl & |
|
(JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) { |
|
if (current->jobctl & JOBCTL_TRAP_MASK) { |
|
do_jobctl_trap(); |
|
spin_unlock_irq(&sighand->siglock); |
|
} else if (current->jobctl & JOBCTL_TRAP_FREEZE) |
|
do_freezer_trap(); |
|
|
|
goto relock; |
|
} |
|
|
|
/* |
|
* If the task is leaving the frozen state, let's update |
|
* cgroup counters and reset the frozen bit. |
|
*/ |
|
if (unlikely(cgroup_task_frozen(current))) { |
|
spin_unlock_irq(&sighand->siglock); |
|
cgroup_leave_frozen(false); |
|
goto relock; |
|
} |
|
|
|
/* |
|
* Signals generated by the execution of an instruction |
|
* need to be delivered before any other pending signals |
|
* so that the instruction pointer in the signal stack |
|
* frame points to the faulting instruction. |
|
*/ |
|
type = PIDTYPE_PID; |
|
signr = dequeue_synchronous_signal(&ksig->info); |
|
if (!signr) |
|
signr = dequeue_signal(current, ¤t->blocked, |
|
&ksig->info, &type); |
|
|
|
if (!signr) |
|
break; /* will return 0 */ |
|
|
|
if (unlikely(current->ptrace) && (signr != SIGKILL) && |
|
!(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) { |
|
signr = ptrace_signal(signr, &ksig->info, type); |
|
if (!signr) |
|
continue; |
|
} |
|
|
|
ka = &sighand->action[signr-1]; |
|
|
|
/* Trace actually delivered signals. */ |
|
trace_signal_deliver(signr, &ksig->info, ka); |
|
|
|
if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
|
continue; |
|
if (ka->sa.sa_handler != SIG_DFL) { |
|
/* Run the handler. */ |
|
ksig->ka = *ka; |
|
|
|
if (ka->sa.sa_flags & SA_ONESHOT) |
|
ka->sa.sa_handler = SIG_DFL; |
|
|
|
break; /* will return non-zero "signr" value */ |
|
} |
|
|
|
/* |
|
* Now we are doing the default action for this signal. |
|
*/ |
|
if (sig_kernel_ignore(signr)) /* Default is nothing. */ |
|
continue; |
|
|
|
/* |
|
* Global init gets no signals it doesn't want. |
|
* Container-init gets no signals it doesn't want from same |
|
* container. |
|
* |
|
* Note that if global/container-init sees a sig_kernel_only() |
|
* signal here, the signal must have been generated internally |
|
* or must have come from an ancestor namespace. In either |
|
* case, the signal cannot be dropped. |
|
*/ |
|
if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
|
!sig_kernel_only(signr)) |
|
continue; |
|
|
|
if (sig_kernel_stop(signr)) { |
|
/* |
|
* The default action is to stop all threads in |
|
* the thread group. The job control signals |
|
* do nothing in an orphaned pgrp, but SIGSTOP |
|
* always works. Note that siglock needs to be |
|
* dropped during the call to is_orphaned_pgrp() |
|
* because of lock ordering with tasklist_lock. |
|
* This allows an intervening SIGCONT to be posted. |
|
* We need to check for that and bail out if necessary. |
|
*/ |
|
if (signr != SIGSTOP) { |
|
spin_unlock_irq(&sighand->siglock); |
|
|
|
/* signals can be posted during this window */ |
|
|
|
if (is_current_pgrp_orphaned()) |
|
goto relock; |
|
|
|
spin_lock_irq(&sighand->siglock); |
|
} |
|
|
|
if (likely(do_signal_stop(ksig->info.si_signo))) { |
|
/* It released the siglock. */ |
|
goto relock; |
|
} |
|
|
|
/* |
|
* We didn't actually stop, due to a race |
|
* with SIGCONT or something like that. |
|
*/ |
|
continue; |
|
} |
|
|
|
fatal: |
|
spin_unlock_irq(&sighand->siglock); |
|
if (unlikely(cgroup_task_frozen(current))) |
|
cgroup_leave_frozen(true); |
|
|
|
/* |
|
* Anything else is fatal, maybe with a core dump. |
|
*/ |
|
current->flags |= PF_SIGNALED; |
|
|
|
if (sig_kernel_coredump(signr)) { |
|
if (print_fatal_signals) |
|
print_fatal_signal(ksig->info.si_signo); |
|
proc_coredump_connector(current); |
|
/* |
|
* If it was able to dump core, this kills all |
|
* other threads in the group and synchronizes with |
|
* their demise. If we lost the race with another |
|
* thread getting here, it set group_exit_code |
|
* first and our do_group_exit call below will use |
|
* that value and ignore the one we pass it. |
|
*/ |
|
do_coredump(&ksig->info); |
|
} |
|
|
|
/* |
|
* PF_IO_WORKER threads will catch and exit on fatal signals |
|
* themselves. They have cleanup that must be performed, so |
|
* we cannot call do_exit() on their behalf. |
|
*/ |
|
if (current->flags & PF_IO_WORKER) |
|
goto out; |
|
|
|
/* |
|
* Death signals, no core dump. |
|
*/ |
|
do_group_exit(ksig->info.si_signo); |
|
/* NOTREACHED */ |
|
} |
|
spin_unlock_irq(&sighand->siglock); |
|
out: |
|
ksig->sig = signr; |
|
|
|
if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS)) |
|
hide_si_addr_tag_bits(ksig); |
|
|
|
return ksig->sig > 0; |
|
} |
|
|
|
/** |
|
* signal_delivered - called after signal delivery to update blocked signals |
|
* @ksig: kernel signal struct |
|
* @stepping: nonzero if debugger single-step or block-step in use |
|
* |
|
* This function should be called when a signal has successfully been |
|
* delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
|
* is always blocked), and the signal itself is blocked unless %SA_NODEFER |
|
* is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
|
*/ |
|
static void signal_delivered(struct ksignal *ksig, int stepping) |
|
{ |
|
sigset_t blocked; |
|
|
|
/* A signal was successfully delivered, and the |
|
saved sigmask was stored on the signal frame, |
|
and will be restored by sigreturn. So we can |
|
simply clear the restore sigmask flag. */ |
|
clear_restore_sigmask(); |
|
|
|
sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
|
if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) |
|
sigaddset(&blocked, ksig->sig); |
|
set_current_blocked(&blocked); |
|
if (current->sas_ss_flags & SS_AUTODISARM) |
|
sas_ss_reset(current); |
|
if (stepping) |
|
ptrace_notify(SIGTRAP, 0); |
|
} |
|
|
|
void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
|
{ |
|
if (failed) |
|
force_sigsegv(ksig->sig); |
|
else |
|
signal_delivered(ksig, stepping); |
|
} |
|
|
|
/* |
|
* It could be that complete_signal() picked us to notify about the |
|
* group-wide signal. Other threads should be notified now to take |
|
* the shared signals in @which since we will not. |
|
*/ |
|
static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
|
{ |
|
sigset_t retarget; |
|
struct task_struct *t; |
|
|
|
sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
|
if (sigisemptyset(&retarget)) |
|
return; |
|
|
|
t = tsk; |
|
while_each_thread(tsk, t) { |
|
if (t->flags & PF_EXITING) |
|
continue; |
|
|
|
if (!has_pending_signals(&retarget, &t->blocked)) |
|
continue; |
|
/* Remove the signals this thread can handle. */ |
|
sigandsets(&retarget, &retarget, &t->blocked); |
|
|
|
if (!task_sigpending(t)) |
|
signal_wake_up(t, 0); |
|
|
|
if (sigisemptyset(&retarget)) |
|
break; |
|
} |
|
} |
|
|
|
void exit_signals(struct task_struct *tsk) |
|
{ |
|
int group_stop = 0; |
|
sigset_t unblocked; |
|
|
|
/* |
|
* @tsk is about to have PF_EXITING set - lock out users which |
|
* expect stable threadgroup. |
|
*/ |
|
cgroup_threadgroup_change_begin(tsk); |
|
|
|
if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) { |
|
tsk->flags |= PF_EXITING; |
|
cgroup_threadgroup_change_end(tsk); |
|
return; |
|
} |
|
|
|
spin_lock_irq(&tsk->sighand->siglock); |
|
/* |
|
* From now this task is not visible for group-wide signals, |
|
* see wants_signal(), do_signal_stop(). |
|
*/ |
|
tsk->flags |= PF_EXITING; |
|
|
|
cgroup_threadgroup_change_end(tsk); |
|
|
|
if (!task_sigpending(tsk)) |
|
goto out; |
|
|
|
unblocked = tsk->blocked; |
|
signotset(&unblocked); |
|
retarget_shared_pending(tsk, &unblocked); |
|
|
|
if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
|
task_participate_group_stop(tsk)) |
|
group_stop = CLD_STOPPED; |
|
out: |
|
spin_unlock_irq(&tsk->sighand->siglock); |
|
|
|
/* |
|
* If group stop has completed, deliver the notification. This |
|
* should always go to the real parent of the group leader. |
|
*/ |
|
if (unlikely(group_stop)) { |
|
read_lock(&tasklist_lock); |
|
do_notify_parent_cldstop(tsk, false, group_stop); |
|
read_unlock(&tasklist_lock); |
|
} |
|
} |
|
|
|
/* |
|
* System call entry points. |
|
*/ |
|
|
|
/** |
|
* sys_restart_syscall - restart a system call |
|
*/ |
|
SYSCALL_DEFINE0(restart_syscall) |
|
{ |
|
struct restart_block *restart = ¤t->restart_block; |
|
return restart->fn(restart); |
|
} |
|
|
|
long do_no_restart_syscall(struct restart_block *param) |
|
{ |
|
return -EINTR; |
|
} |
|
|
|
static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
|
{ |
|
if (task_sigpending(tsk) && !thread_group_empty(tsk)) { |
|
sigset_t newblocked; |
|
/* A set of now blocked but previously unblocked signals. */ |
|
sigandnsets(&newblocked, newset, ¤t->blocked); |
|
retarget_shared_pending(tsk, &newblocked); |
|
} |
|
tsk->blocked = *newset; |
|
recalc_sigpending(); |
|
} |
|
|
|
/** |
|
* set_current_blocked - change current->blocked mask |
|
* @newset: new mask |
|
* |
|
* It is wrong to change ->blocked directly, this helper should be used |
|
* to ensure the process can't miss a shared signal we are going to block. |
|
*/ |
|
void set_current_blocked(sigset_t *newset) |
|
{ |
|
sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
|
__set_current_blocked(newset); |
|
} |
|
|
|
void __set_current_blocked(const sigset_t *newset) |
|
{ |
|
struct task_struct *tsk = current; |
|
|
|
/* |
|
* In case the signal mask hasn't changed, there is nothing we need |
|
* to do. The current->blocked shouldn't be modified by other task. |
|
*/ |
|
if (sigequalsets(&tsk->blocked, newset)) |
|
return; |
|
|
|
spin_lock_irq(&tsk->sighand->siglock); |
|
__set_task_blocked(tsk, newset); |
|
spin_unlock_irq(&tsk->sighand->siglock); |
|
} |
|
|
|
/* |
|
* This is also useful for kernel threads that want to temporarily |
|
* (or permanently) block certain signals. |
|
* |
|
* NOTE! Unlike the user-mode sys_sigprocmask(), the kernel |
|
* interface happily blocks "unblockable" signals like SIGKILL |
|
* and friends. |
|
*/ |
|
int sigprocmask(int how, sigset_t *set, sigset_t *oldset) |
|
{ |
|
struct task_struct *tsk = current; |
|
sigset_t newset; |
|
|
|
/* Lockless, only current can change ->blocked, never from irq */ |
|
if (oldset) |
|
*oldset = tsk->blocked; |
|
|
|
switch (how) { |
|
case SIG_BLOCK: |
|
sigorsets(&newset, &tsk->blocked, set); |
|
break; |
|
case SIG_UNBLOCK: |
|
sigandnsets(&newset, &tsk->blocked, set); |
|
break; |
|
case SIG_SETMASK: |
|
newset = *set; |
|
break; |
|
default: |
|
return -EINVAL; |
|
} |
|
|
|
__set_current_blocked(&newset); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL(sigprocmask); |
|
|
|
/* |
|
* The api helps set app-provided sigmasks. |
|
* |
|
* This is useful for syscalls such as ppoll, pselect, io_pgetevents and |
|
* epoll_pwait where a new sigmask is passed from userland for the syscalls. |
|
* |
|
* Note that it does set_restore_sigmask() in advance, so it must be always |
|
* paired with restore_saved_sigmask_unless() before return from syscall. |
|
*/ |
|
int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize) |
|
{ |
|
sigset_t kmask; |
|
|
|
if (!umask) |
|
return 0; |
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
if (copy_from_user(&kmask, umask, sizeof(sigset_t))) |
|
return -EFAULT; |
|
|
|
set_restore_sigmask(); |
|
current->saved_sigmask = current->blocked; |
|
set_current_blocked(&kmask); |
|
|
|
return 0; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
int set_compat_user_sigmask(const compat_sigset_t __user *umask, |
|
size_t sigsetsize) |
|
{ |
|
sigset_t kmask; |
|
|
|
if (!umask) |
|
return 0; |
|
if (sigsetsize != sizeof(compat_sigset_t)) |
|
return -EINVAL; |
|
if (get_compat_sigset(&kmask, umask)) |
|
return -EFAULT; |
|
|
|
set_restore_sigmask(); |
|
current->saved_sigmask = current->blocked; |
|
set_current_blocked(&kmask); |
|
|
|
return 0; |
|
} |
|
#endif |
|
|
|
/** |
|
* sys_rt_sigprocmask - change the list of currently blocked signals |
|
* @how: whether to add, remove, or set signals |
|
* @nset: stores pending signals |
|
* @oset: previous value of signal mask if non-null |
|
* @sigsetsize: size of sigset_t type |
|
*/ |
|
SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
|
sigset_t __user *, oset, size_t, sigsetsize) |
|
{ |
|
sigset_t old_set, new_set; |
|
int error; |
|
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */ |
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
old_set = current->blocked; |
|
|
|
if (nset) { |
|
if (copy_from_user(&new_set, nset, sizeof(sigset_t))) |
|
return -EFAULT; |
|
sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
|
|
|
error = sigprocmask(how, &new_set, NULL); |
|
if (error) |
|
return error; |
|
} |
|
|
|
if (oset) { |
|
if (copy_to_user(oset, &old_set, sizeof(sigset_t))) |
|
return -EFAULT; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
|
compat_sigset_t __user *, oset, compat_size_t, sigsetsize) |
|
{ |
|
sigset_t old_set = current->blocked; |
|
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */ |
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
if (nset) { |
|
sigset_t new_set; |
|
int error; |
|
if (get_compat_sigset(&new_set, nset)) |
|
return -EFAULT; |
|
sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
|
|
|
error = sigprocmask(how, &new_set, NULL); |
|
if (error) |
|
return error; |
|
} |
|
return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0; |
|
} |
|
#endif |
|
|
|
static void do_sigpending(sigset_t *set) |
|
{ |
|
spin_lock_irq(¤t->sighand->siglock); |
|
sigorsets(set, ¤t->pending.signal, |
|
¤t->signal->shared_pending.signal); |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
|
|
/* Outside the lock because only this thread touches it. */ |
|
sigandsets(set, ¤t->blocked, set); |
|
} |
|
|
|
/** |
|
* sys_rt_sigpending - examine a pending signal that has been raised |
|
* while blocked |
|
* @uset: stores pending signals |
|
* @sigsetsize: size of sigset_t type or larger |
|
*/ |
|
SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
|
{ |
|
sigset_t set; |
|
|
|
if (sigsetsize > sizeof(*uset)) |
|
return -EINVAL; |
|
|
|
do_sigpending(&set); |
|
|
|
if (copy_to_user(uset, &set, sigsetsize)) |
|
return -EFAULT; |
|
|
|
return 0; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
|
compat_size_t, sigsetsize) |
|
{ |
|
sigset_t set; |
|
|
|
if (sigsetsize > sizeof(*uset)) |
|
return -EINVAL; |
|
|
|
do_sigpending(&set); |
|
|
|
return put_compat_sigset(uset, &set, sigsetsize); |
|
} |
|
#endif |
|
|
|
static const struct { |
|
unsigned char limit, layout; |
|
} sig_sicodes[] = { |
|
[SIGILL] = { NSIGILL, SIL_FAULT }, |
|
[SIGFPE] = { NSIGFPE, SIL_FAULT }, |
|
[SIGSEGV] = { NSIGSEGV, SIL_FAULT }, |
|
[SIGBUS] = { NSIGBUS, SIL_FAULT }, |
|
[SIGTRAP] = { NSIGTRAP, SIL_FAULT }, |
|
#if defined(SIGEMT) |
|
[SIGEMT] = { NSIGEMT, SIL_FAULT }, |
|
#endif |
|
[SIGCHLD] = { NSIGCHLD, SIL_CHLD }, |
|
[SIGPOLL] = { NSIGPOLL, SIL_POLL }, |
|
[SIGSYS] = { NSIGSYS, SIL_SYS }, |
|
}; |
|
|
|
static bool known_siginfo_layout(unsigned sig, int si_code) |
|
{ |
|
if (si_code == SI_KERNEL) |
|
return true; |
|
else if ((si_code > SI_USER)) { |
|
if (sig_specific_sicodes(sig)) { |
|
if (si_code <= sig_sicodes[sig].limit) |
|
return true; |
|
} |
|
else if (si_code <= NSIGPOLL) |
|
return true; |
|
} |
|
else if (si_code >= SI_DETHREAD) |
|
return true; |
|
else if (si_code == SI_ASYNCNL) |
|
return true; |
|
return false; |
|
} |
|
|
|
enum siginfo_layout siginfo_layout(unsigned sig, int si_code) |
|
{ |
|
enum siginfo_layout layout = SIL_KILL; |
|
if ((si_code > SI_USER) && (si_code < SI_KERNEL)) { |
|
if ((sig < ARRAY_SIZE(sig_sicodes)) && |
|
(si_code <= sig_sicodes[sig].limit)) { |
|
layout = sig_sicodes[sig].layout; |
|
/* Handle the exceptions */ |
|
if ((sig == SIGBUS) && |
|
(si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO)) |
|
layout = SIL_FAULT_MCEERR; |
|
else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR)) |
|
layout = SIL_FAULT_BNDERR; |
|
#ifdef SEGV_PKUERR |
|
else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR)) |
|
layout = SIL_FAULT_PKUERR; |
|
#endif |
|
else if ((sig == SIGTRAP) && (si_code == TRAP_PERF)) |
|
layout = SIL_FAULT_PERF_EVENT; |
|
else if (IS_ENABLED(CONFIG_SPARC) && |
|
(sig == SIGILL) && (si_code == ILL_ILLTRP)) |
|
layout = SIL_FAULT_TRAPNO; |
|
else if (IS_ENABLED(CONFIG_ALPHA) && |
|
((sig == SIGFPE) || |
|
((sig == SIGTRAP) && (si_code == TRAP_UNK)))) |
|
layout = SIL_FAULT_TRAPNO; |
|
} |
|
else if (si_code <= NSIGPOLL) |
|
layout = SIL_POLL; |
|
} else { |
|
if (si_code == SI_TIMER) |
|
layout = SIL_TIMER; |
|
else if (si_code == SI_SIGIO) |
|
layout = SIL_POLL; |
|
else if (si_code < 0) |
|
layout = SIL_RT; |
|
} |
|
return layout; |
|
} |
|
|
|
static inline char __user *si_expansion(const siginfo_t __user *info) |
|
{ |
|
return ((char __user *)info) + sizeof(struct kernel_siginfo); |
|
} |
|
|
|
int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from) |
|
{ |
|
char __user *expansion = si_expansion(to); |
|
if (copy_to_user(to, from , sizeof(struct kernel_siginfo))) |
|
return -EFAULT; |
|
if (clear_user(expansion, SI_EXPANSION_SIZE)) |
|
return -EFAULT; |
|
return 0; |
|
} |
|
|
|
static int post_copy_siginfo_from_user(kernel_siginfo_t *info, |
|
const siginfo_t __user *from) |
|
{ |
|
if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) { |
|
char __user *expansion = si_expansion(from); |
|
char buf[SI_EXPANSION_SIZE]; |
|
int i; |
|
/* |
|
* An unknown si_code might need more than |
|
* sizeof(struct kernel_siginfo) bytes. Verify all of the |
|
* extra bytes are 0. This guarantees copy_siginfo_to_user |
|
* will return this data to userspace exactly. |
|
*/ |
|
if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE)) |
|
return -EFAULT; |
|
for (i = 0; i < SI_EXPANSION_SIZE; i++) { |
|
if (buf[i] != 0) |
|
return -E2BIG; |
|
} |
|
} |
|
return 0; |
|
} |
|
|
|
static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to, |
|
const siginfo_t __user *from) |
|
{ |
|
if (copy_from_user(to, from, sizeof(struct kernel_siginfo))) |
|
return -EFAULT; |
|
to->si_signo = signo; |
|
return post_copy_siginfo_from_user(to, from); |
|
} |
|
|
|
int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from) |
|
{ |
|
if (copy_from_user(to, from, sizeof(struct kernel_siginfo))) |
|
return -EFAULT; |
|
return post_copy_siginfo_from_user(to, from); |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
/** |
|
* copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo |
|
* @to: compat siginfo destination |
|
* @from: kernel siginfo source |
|
* |
|
* Note: This function does not work properly for the SIGCHLD on x32, but |
|
* fortunately it doesn't have to. The only valid callers for this function are |
|
* copy_siginfo_to_user32, which is overriden for x32 and the coredump code. |
|
* The latter does not care because SIGCHLD will never cause a coredump. |
|
*/ |
|
void copy_siginfo_to_external32(struct compat_siginfo *to, |
|
const struct kernel_siginfo *from) |
|
{ |
|
memset(to, 0, sizeof(*to)); |
|
|
|
to->si_signo = from->si_signo; |
|
to->si_errno = from->si_errno; |
|
to->si_code = from->si_code; |
|
switch(siginfo_layout(from->si_signo, from->si_code)) { |
|
case SIL_KILL: |
|
to->si_pid = from->si_pid; |
|
to->si_uid = from->si_uid; |
|
break; |
|
case SIL_TIMER: |
|
to->si_tid = from->si_tid; |
|
to->si_overrun = from->si_overrun; |
|
to->si_int = from->si_int; |
|
break; |
|
case SIL_POLL: |
|
to->si_band = from->si_band; |
|
to->si_fd = from->si_fd; |
|
break; |
|
case SIL_FAULT: |
|
to->si_addr = ptr_to_compat(from->si_addr); |
|
break; |
|
case SIL_FAULT_TRAPNO: |
|
to->si_addr = ptr_to_compat(from->si_addr); |
|
to->si_trapno = from->si_trapno; |
|
break; |
|
case SIL_FAULT_MCEERR: |
|
to->si_addr = ptr_to_compat(from->si_addr); |
|
to->si_addr_lsb = from->si_addr_lsb; |
|
break; |
|
case SIL_FAULT_BNDERR: |
|
to->si_addr = ptr_to_compat(from->si_addr); |
|
to->si_lower = ptr_to_compat(from->si_lower); |
|
to->si_upper = ptr_to_compat(from->si_upper); |
|
break; |
|
case SIL_FAULT_PKUERR: |
|
to->si_addr = ptr_to_compat(from->si_addr); |
|
to->si_pkey = from->si_pkey; |
|
break; |
|
case SIL_FAULT_PERF_EVENT: |
|
to->si_addr = ptr_to_compat(from->si_addr); |
|
to->si_perf_data = from->si_perf_data; |
|
to->si_perf_type = from->si_perf_type; |
|
to->si_perf_flags = from->si_perf_flags; |
|
break; |
|
case SIL_CHLD: |
|
to->si_pid = from->si_pid; |
|
to->si_uid = from->si_uid; |
|
to->si_status = from->si_status; |
|
to->si_utime = from->si_utime; |
|
to->si_stime = from->si_stime; |
|
break; |
|
case SIL_RT: |
|
to->si_pid = from->si_pid; |
|
to->si_uid = from->si_uid; |
|
to->si_int = from->si_int; |
|
break; |
|
case SIL_SYS: |
|
to->si_call_addr = ptr_to_compat(from->si_call_addr); |
|
to->si_syscall = from->si_syscall; |
|
to->si_arch = from->si_arch; |
|
break; |
|
} |
|
} |
|
|
|
int __copy_siginfo_to_user32(struct compat_siginfo __user *to, |
|
const struct kernel_siginfo *from) |
|
{ |
|
struct compat_siginfo new; |
|
|
|
copy_siginfo_to_external32(&new, from); |
|
if (copy_to_user(to, &new, sizeof(struct compat_siginfo))) |
|
return -EFAULT; |
|
return 0; |
|
} |
|
|
|
static int post_copy_siginfo_from_user32(kernel_siginfo_t *to, |
|
const struct compat_siginfo *from) |
|
{ |
|
clear_siginfo(to); |
|
to->si_signo = from->si_signo; |
|
to->si_errno = from->si_errno; |
|
to->si_code = from->si_code; |
|
switch(siginfo_layout(from->si_signo, from->si_code)) { |
|
case SIL_KILL: |
|
to->si_pid = from->si_pid; |
|
to->si_uid = from->si_uid; |
|
break; |
|
case SIL_TIMER: |
|
to->si_tid = from->si_tid; |
|
to->si_overrun = from->si_overrun; |
|
to->si_int = from->si_int; |
|
break; |
|
case SIL_POLL: |
|
to->si_band = from->si_band; |
|
to->si_fd = from->si_fd; |
|
break; |
|
case SIL_FAULT: |
|
to->si_addr = compat_ptr(from->si_addr); |
|
break; |
|
case SIL_FAULT_TRAPNO: |
|
to->si_addr = compat_ptr(from->si_addr); |
|
to->si_trapno = from->si_trapno; |
|
break; |
|
case SIL_FAULT_MCEERR: |
|
to->si_addr = compat_ptr(from->si_addr); |
|
to->si_addr_lsb = from->si_addr_lsb; |
|
break; |
|
case SIL_FAULT_BNDERR: |
|
to->si_addr = compat_ptr(from->si_addr); |
|
to->si_lower = compat_ptr(from->si_lower); |
|
to->si_upper = compat_ptr(from->si_upper); |
|
break; |
|
case SIL_FAULT_PKUERR: |
|
to->si_addr = compat_ptr(from->si_addr); |
|
to->si_pkey = from->si_pkey; |
|
break; |
|
case SIL_FAULT_PERF_EVENT: |
|
to->si_addr = compat_ptr(from->si_addr); |
|
to->si_perf_data = from->si_perf_data; |
|
to->si_perf_type = from->si_perf_type; |
|
to->si_perf_flags = from->si_perf_flags; |
|
break; |
|
case SIL_CHLD: |
|
to->si_pid = from->si_pid; |
|
to->si_uid = from->si_uid; |
|
to->si_status = from->si_status; |
|
#ifdef CONFIG_X86_X32_ABI |
|
if (in_x32_syscall()) { |
|
to->si_utime = from->_sifields._sigchld_x32._utime; |
|
to->si_stime = from->_sifields._sigchld_x32._stime; |
|
} else |
|
#endif |
|
{ |
|
to->si_utime = from->si_utime; |
|
to->si_stime = from->si_stime; |
|
} |
|
break; |
|
case SIL_RT: |
|
to->si_pid = from->si_pid; |
|
to->si_uid = from->si_uid; |
|
to->si_int = from->si_int; |
|
break; |
|
case SIL_SYS: |
|
to->si_call_addr = compat_ptr(from->si_call_addr); |
|
to->si_syscall = from->si_syscall; |
|
to->si_arch = from->si_arch; |
|
break; |
|
} |
|
return 0; |
|
} |
|
|
|
static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to, |
|
const struct compat_siginfo __user *ufrom) |
|
{ |
|
struct compat_siginfo from; |
|
|
|
if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo))) |
|
return -EFAULT; |
|
|
|
from.si_signo = signo; |
|
return post_copy_siginfo_from_user32(to, &from); |
|
} |
|
|
|
int copy_siginfo_from_user32(struct kernel_siginfo *to, |
|
const struct compat_siginfo __user *ufrom) |
|
{ |
|
struct compat_siginfo from; |
|
|
|
if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo))) |
|
return -EFAULT; |
|
|
|
return post_copy_siginfo_from_user32(to, &from); |
|
} |
|
#endif /* CONFIG_COMPAT */ |
|
|
|
/** |
|
* do_sigtimedwait - wait for queued signals specified in @which |
|
* @which: queued signals to wait for |
|
* @info: if non-null, the signal's siginfo is returned here |
|
* @ts: upper bound on process time suspension |
|
*/ |
|
static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info, |
|
const struct timespec64 *ts) |
|
{ |
|
ktime_t *to = NULL, timeout = KTIME_MAX; |
|
struct task_struct *tsk = current; |
|
sigset_t mask = *which; |
|
enum pid_type type; |
|
int sig, ret = 0; |
|
|
|
if (ts) { |
|
if (!timespec64_valid(ts)) |
|
return -EINVAL; |
|
timeout = timespec64_to_ktime(*ts); |
|
to = &timeout; |
|
} |
|
|
|
/* |
|
* Invert the set of allowed signals to get those we want to block. |
|
*/ |
|
sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
|
signotset(&mask); |
|
|
|
spin_lock_irq(&tsk->sighand->siglock); |
|
sig = dequeue_signal(tsk, &mask, info, &type); |
|
if (!sig && timeout) { |
|
/* |
|
* None ready, temporarily unblock those we're interested |
|
* while we are sleeping in so that we'll be awakened when |
|
* they arrive. Unblocking is always fine, we can avoid |
|
* set_current_blocked(). |
|
*/ |
|
tsk->real_blocked = tsk->blocked; |
|
sigandsets(&tsk->blocked, &tsk->blocked, &mask); |
|
recalc_sigpending(); |
|
spin_unlock_irq(&tsk->sighand->siglock); |
|
|
|
__set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE); |
|
ret = schedule_hrtimeout_range(to, tsk->timer_slack_ns, |
|
HRTIMER_MODE_REL); |
|
spin_lock_irq(&tsk->sighand->siglock); |
|
__set_task_blocked(tsk, &tsk->real_blocked); |
|
sigemptyset(&tsk->real_blocked); |
|
sig = dequeue_signal(tsk, &mask, info, &type); |
|
} |
|
spin_unlock_irq(&tsk->sighand->siglock); |
|
|
|
if (sig) |
|
return sig; |
|
return ret ? -EINTR : -EAGAIN; |
|
} |
|
|
|
/** |
|
* sys_rt_sigtimedwait - synchronously wait for queued signals specified |
|
* in @uthese |
|
* @uthese: queued signals to wait for |
|
* @uinfo: if non-null, the signal's siginfo is returned here |
|
* @uts: upper bound on process time suspension |
|
* @sigsetsize: size of sigset_t type |
|
*/ |
|
SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
|
siginfo_t __user *, uinfo, |
|
const struct __kernel_timespec __user *, uts, |
|
size_t, sigsetsize) |
|
{ |
|
sigset_t these; |
|
struct timespec64 ts; |
|
kernel_siginfo_t info; |
|
int ret; |
|
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */ |
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
if (copy_from_user(&these, uthese, sizeof(these))) |
|
return -EFAULT; |
|
|
|
if (uts) { |
|
if (get_timespec64(&ts, uts)) |
|
return -EFAULT; |
|
} |
|
|
|
ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
|
|
|
if (ret > 0 && uinfo) { |
|
if (copy_siginfo_to_user(uinfo, &info)) |
|
ret = -EFAULT; |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT_32BIT_TIME |
|
SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese, |
|
siginfo_t __user *, uinfo, |
|
const struct old_timespec32 __user *, uts, |
|
size_t, sigsetsize) |
|
{ |
|
sigset_t these; |
|
struct timespec64 ts; |
|
kernel_siginfo_t info; |
|
int ret; |
|
|
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
if (copy_from_user(&these, uthese, sizeof(these))) |
|
return -EFAULT; |
|
|
|
if (uts) { |
|
if (get_old_timespec32(&ts, uts)) |
|
return -EFAULT; |
|
} |
|
|
|
ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
|
|
|
if (ret > 0 && uinfo) { |
|
if (copy_siginfo_to_user(uinfo, &info)) |
|
ret = -EFAULT; |
|
} |
|
|
|
return ret; |
|
} |
|
#endif |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese, |
|
struct compat_siginfo __user *, uinfo, |
|
struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize) |
|
{ |
|
sigset_t s; |
|
struct timespec64 t; |
|
kernel_siginfo_t info; |
|
long ret; |
|
|
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
if (get_compat_sigset(&s, uthese)) |
|
return -EFAULT; |
|
|
|
if (uts) { |
|
if (get_timespec64(&t, uts)) |
|
return -EFAULT; |
|
} |
|
|
|
ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); |
|
|
|
if (ret > 0 && uinfo) { |
|
if (copy_siginfo_to_user32(uinfo, &info)) |
|
ret = -EFAULT; |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT_32BIT_TIME |
|
COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese, |
|
struct compat_siginfo __user *, uinfo, |
|
struct old_timespec32 __user *, uts, compat_size_t, sigsetsize) |
|
{ |
|
sigset_t s; |
|
struct timespec64 t; |
|
kernel_siginfo_t info; |
|
long ret; |
|
|
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
if (get_compat_sigset(&s, uthese)) |
|
return -EFAULT; |
|
|
|
if (uts) { |
|
if (get_old_timespec32(&t, uts)) |
|
return -EFAULT; |
|
} |
|
|
|
ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); |
|
|
|
if (ret > 0 && uinfo) { |
|
if (copy_siginfo_to_user32(uinfo, &info)) |
|
ret = -EFAULT; |
|
} |
|
|
|
return ret; |
|
} |
|
#endif |
|
#endif |
|
|
|
static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info) |
|
{ |
|
clear_siginfo(info); |
|
info->si_signo = sig; |
|
info->si_errno = 0; |
|
info->si_code = SI_USER; |
|
info->si_pid = task_tgid_vnr(current); |
|
info->si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
|
} |
|
|
|
/** |
|
* sys_kill - send a signal to a process |
|
* @pid: the PID of the process |
|
* @sig: signal to be sent |
|
*/ |
|
SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
prepare_kill_siginfo(sig, &info); |
|
|
|
return kill_something_info(sig, &info, pid); |
|
} |
|
|
|
/* |
|
* Verify that the signaler and signalee either are in the same pid namespace |
|
* or that the signaler's pid namespace is an ancestor of the signalee's pid |
|
* namespace. |
|
*/ |
|
static bool access_pidfd_pidns(struct pid *pid) |
|
{ |
|
struct pid_namespace *active = task_active_pid_ns(current); |
|
struct pid_namespace *p = ns_of_pid(pid); |
|
|
|
for (;;) { |
|
if (!p) |
|
return false; |
|
if (p == active) |
|
break; |
|
p = p->parent; |
|
} |
|
|
|
return true; |
|
} |
|
|
|
static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, |
|
siginfo_t __user *info) |
|
{ |
|
#ifdef CONFIG_COMPAT |
|
/* |
|
* Avoid hooking up compat syscalls and instead handle necessary |
|
* conversions here. Note, this is a stop-gap measure and should not be |
|
* considered a generic solution. |
|
*/ |
|
if (in_compat_syscall()) |
|
return copy_siginfo_from_user32( |
|
kinfo, (struct compat_siginfo __user *)info); |
|
#endif |
|
return copy_siginfo_from_user(kinfo, info); |
|
} |
|
|
|
static struct pid *pidfd_to_pid(const struct file *file) |
|
{ |
|
struct pid *pid; |
|
|
|
pid = pidfd_pid(file); |
|
if (!IS_ERR(pid)) |
|
return pid; |
|
|
|
return tgid_pidfd_to_pid(file); |
|
} |
|
|
|
/** |
|
* sys_pidfd_send_signal - Signal a process through a pidfd |
|
* @pidfd: file descriptor of the process |
|
* @sig: signal to send |
|
* @info: signal info |
|
* @flags: future flags |
|
* |
|
* The syscall currently only signals via PIDTYPE_PID which covers |
|
* kill(<positive-pid>, <signal>. It does not signal threads or process |
|
* groups. |
|
* In order to extend the syscall to threads and process groups the @flags |
|
* argument should be used. In essence, the @flags argument will determine |
|
* what is signaled and not the file descriptor itself. Put in other words, |
|
* grouping is a property of the flags argument not a property of the file |
|
* descriptor. |
|
* |
|
* Return: 0 on success, negative errno on failure |
|
*/ |
|
SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, |
|
siginfo_t __user *, info, unsigned int, flags) |
|
{ |
|
int ret; |
|
struct fd f; |
|
struct pid *pid; |
|
kernel_siginfo_t kinfo; |
|
|
|
/* Enforce flags be set to 0 until we add an extension. */ |
|
if (flags) |
|
return -EINVAL; |
|
|
|
f = fdget(pidfd); |
|
if (!f.file) |
|
return -EBADF; |
|
|
|
/* Is this a pidfd? */ |
|
pid = pidfd_to_pid(f.file); |
|
if (IS_ERR(pid)) { |
|
ret = PTR_ERR(pid); |
|
goto err; |
|
} |
|
|
|
ret = -EINVAL; |
|
if (!access_pidfd_pidns(pid)) |
|
goto err; |
|
|
|
if (info) { |
|
ret = copy_siginfo_from_user_any(&kinfo, info); |
|
if (unlikely(ret)) |
|
goto err; |
|
|
|
ret = -EINVAL; |
|
if (unlikely(sig != kinfo.si_signo)) |
|
goto err; |
|
|
|
/* Only allow sending arbitrary signals to yourself. */ |
|
ret = -EPERM; |
|
if ((task_pid(current) != pid) && |
|
(kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) |
|
goto err; |
|
} else { |
|
prepare_kill_siginfo(sig, &kinfo); |
|
} |
|
|
|
ret = kill_pid_info(sig, &kinfo, pid); |
|
|
|
err: |
|
fdput(f); |
|
return ret; |
|
} |
|
|
|
static int |
|
do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info) |
|
{ |
|
struct task_struct *p; |
|
int error = -ESRCH; |
|
|
|
rcu_read_lock(); |
|
p = find_task_by_vpid(pid); |
|
if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
|
error = check_kill_permission(sig, info, p); |
|
/* |
|
* The null signal is a permissions and process existence |
|
* probe. No signal is actually delivered. |
|
*/ |
|
if (!error && sig) { |
|
error = do_send_sig_info(sig, info, p, PIDTYPE_PID); |
|
/* |
|
* If lock_task_sighand() failed we pretend the task |
|
* dies after receiving the signal. The window is tiny, |
|
* and the signal is private anyway. |
|
*/ |
|
if (unlikely(error == -ESRCH)) |
|
error = 0; |
|
} |
|
} |
|
rcu_read_unlock(); |
|
|
|
return error; |
|
} |
|
|
|
static int do_tkill(pid_t tgid, pid_t pid, int sig) |
|
{ |
|
struct kernel_siginfo info; |
|
|
|
clear_siginfo(&info); |
|
info.si_signo = sig; |
|
info.si_errno = 0; |
|
info.si_code = SI_TKILL; |
|
info.si_pid = task_tgid_vnr(current); |
|
info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
|
|
|
return do_send_specific(tgid, pid, sig, &info); |
|
} |
|
|
|
/** |
|
* sys_tgkill - send signal to one specific thread |
|
* @tgid: the thread group ID of the thread |
|
* @pid: the PID of the thread |
|
* @sig: signal to be sent |
|
* |
|
* This syscall also checks the @tgid and returns -ESRCH even if the PID |
|
* exists but it's not belonging to the target process anymore. This |
|
* method solves the problem of threads exiting and PIDs getting reused. |
|
*/ |
|
SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
|
{ |
|
/* This is only valid for single tasks */ |
|
if (pid <= 0 || tgid <= 0) |
|
return -EINVAL; |
|
|
|
return do_tkill(tgid, pid, sig); |
|
} |
|
|
|
/** |
|
* sys_tkill - send signal to one specific task |
|
* @pid: the PID of the task |
|
* @sig: signal to be sent |
|
* |
|
* Send a signal to only one task, even if it's a CLONE_THREAD task. |
|
*/ |
|
SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
|
{ |
|
/* This is only valid for single tasks */ |
|
if (pid <= 0) |
|
return -EINVAL; |
|
|
|
return do_tkill(0, pid, sig); |
|
} |
|
|
|
static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info) |
|
{ |
|
/* Not even root can pretend to send signals from the kernel. |
|
* Nor can they impersonate a kill()/tgkill(), which adds source info. |
|
*/ |
|
if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
|
(task_pid_vnr(current) != pid)) |
|
return -EPERM; |
|
|
|
/* POSIX.1b doesn't mention process groups. */ |
|
return kill_proc_info(sig, info, pid); |
|
} |
|
|
|
/** |
|
* sys_rt_sigqueueinfo - send signal information to a signal |
|
* @pid: the PID of the thread |
|
* @sig: signal to be sent |
|
* @uinfo: signal info to be sent |
|
*/ |
|
SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
|
siginfo_t __user *, uinfo) |
|
{ |
|
kernel_siginfo_t info; |
|
int ret = __copy_siginfo_from_user(sig, &info, uinfo); |
|
if (unlikely(ret)) |
|
return ret; |
|
return do_rt_sigqueueinfo(pid, sig, &info); |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
|
compat_pid_t, pid, |
|
int, sig, |
|
struct compat_siginfo __user *, uinfo) |
|
{ |
|
kernel_siginfo_t info; |
|
int ret = __copy_siginfo_from_user32(sig, &info, uinfo); |
|
if (unlikely(ret)) |
|
return ret; |
|
return do_rt_sigqueueinfo(pid, sig, &info); |
|
} |
|
#endif |
|
|
|
static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info) |
|
{ |
|
/* This is only valid for single tasks */ |
|
if (pid <= 0 || tgid <= 0) |
|
return -EINVAL; |
|
|
|
/* Not even root can pretend to send signals from the kernel. |
|
* Nor can they impersonate a kill()/tgkill(), which adds source info. |
|
*/ |
|
if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
|
(task_pid_vnr(current) != pid)) |
|
return -EPERM; |
|
|
|
return do_send_specific(tgid, pid, sig, info); |
|
} |
|
|
|
SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, |
|
siginfo_t __user *, uinfo) |
|
{ |
|
kernel_siginfo_t info; |
|
int ret = __copy_siginfo_from_user(sig, &info, uinfo); |
|
if (unlikely(ret)) |
|
return ret; |
|
return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, |
|
compat_pid_t, tgid, |
|
compat_pid_t, pid, |
|
int, sig, |
|
struct compat_siginfo __user *, uinfo) |
|
{ |
|
kernel_siginfo_t info; |
|
int ret = __copy_siginfo_from_user32(sig, &info, uinfo); |
|
if (unlikely(ret)) |
|
return ret; |
|
return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); |
|
} |
|
#endif |
|
|
|
/* |
|
* For kthreads only, must not be used if cloned with CLONE_SIGHAND |
|
*/ |
|
void kernel_sigaction(int sig, __sighandler_t action) |
|
{ |
|
spin_lock_irq(¤t->sighand->siglock); |
|
current->sighand->action[sig - 1].sa.sa_handler = action; |
|
if (action == SIG_IGN) { |
|
sigset_t mask; |
|
|
|
sigemptyset(&mask); |
|
sigaddset(&mask, sig); |
|
|
|
flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
|
flush_sigqueue_mask(&mask, ¤t->pending); |
|
recalc_sigpending(); |
|
} |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
} |
|
EXPORT_SYMBOL(kernel_sigaction); |
|
|
|
void __weak sigaction_compat_abi(struct k_sigaction *act, |
|
struct k_sigaction *oact) |
|
{ |
|
} |
|
|
|
int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
|
{ |
|
struct task_struct *p = current, *t; |
|
struct k_sigaction *k; |
|
sigset_t mask; |
|
|
|
if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
|
return -EINVAL; |
|
|
|
k = &p->sighand->action[sig-1]; |
|
|
|
spin_lock_irq(&p->sighand->siglock); |
|
if (k->sa.sa_flags & SA_IMMUTABLE) { |
|
spin_unlock_irq(&p->sighand->siglock); |
|
return -EINVAL; |
|
} |
|
if (oact) |
|
*oact = *k; |
|
|
|
/* |
|
* Make sure that we never accidentally claim to support SA_UNSUPPORTED, |
|
* e.g. by having an architecture use the bit in their uapi. |
|
*/ |
|
BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED); |
|
|
|
/* |
|
* Clear unknown flag bits in order to allow userspace to detect missing |
|
* support for flag bits and to allow the kernel to use non-uapi bits |
|
* internally. |
|
*/ |
|
if (act) |
|
act->sa.sa_flags &= UAPI_SA_FLAGS; |
|
if (oact) |
|
oact->sa.sa_flags &= UAPI_SA_FLAGS; |
|
|
|
sigaction_compat_abi(act, oact); |
|
|
|
if (act) { |
|
sigdelsetmask(&act->sa.sa_mask, |
|
sigmask(SIGKILL) | sigmask(SIGSTOP)); |
|
*k = *act; |
|
/* |
|
* POSIX 3.3.1.3: |
|
* "Setting a signal action to SIG_IGN for a signal that is |
|
* pending shall cause the pending signal to be discarded, |
|
* whether or not it is blocked." |
|
* |
|
* "Setting a signal action to SIG_DFL for a signal that is |
|
* pending and whose default action is to ignore the signal |
|
* (for example, SIGCHLD), shall cause the pending signal to |
|
* be discarded, whether or not it is blocked" |
|
*/ |
|
if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
|
sigemptyset(&mask); |
|
sigaddset(&mask, sig); |
|
flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
|
for_each_thread(p, t) |
|
flush_sigqueue_mask(&mask, &t->pending); |
|
} |
|
} |
|
|
|
spin_unlock_irq(&p->sighand->siglock); |
|
return 0; |
|
} |
|
|
|
#ifdef CONFIG_DYNAMIC_SIGFRAME |
|
static inline void sigaltstack_lock(void) |
|
__acquires(¤t->sighand->siglock) |
|
{ |
|
spin_lock_irq(¤t->sighand->siglock); |
|
} |
|
|
|
static inline void sigaltstack_unlock(void) |
|
__releases(¤t->sighand->siglock) |
|
{ |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
} |
|
#else |
|
static inline void sigaltstack_lock(void) { } |
|
static inline void sigaltstack_unlock(void) { } |
|
#endif |
|
|
|
static int |
|
do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, |
|
size_t min_ss_size) |
|
{ |
|
struct task_struct *t = current; |
|
int ret = 0; |
|
|
|
if (oss) { |
|
memset(oss, 0, sizeof(stack_t)); |
|
oss->ss_sp = (void __user *) t->sas_ss_sp; |
|
oss->ss_size = t->sas_ss_size; |
|
oss->ss_flags = sas_ss_flags(sp) | |
|
(current->sas_ss_flags & SS_FLAG_BITS); |
|
} |
|
|
|
if (ss) { |
|
void __user *ss_sp = ss->ss_sp; |
|
size_t ss_size = ss->ss_size; |
|
unsigned ss_flags = ss->ss_flags; |
|
int ss_mode; |
|
|
|
if (unlikely(on_sig_stack(sp))) |
|
return -EPERM; |
|
|
|
ss_mode = ss_flags & ~SS_FLAG_BITS; |
|
if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
|
ss_mode != 0)) |
|
return -EINVAL; |
|
|
|
/* |
|
* Return before taking any locks if no actual |
|
* sigaltstack changes were requested. |
|
*/ |
|
if (t->sas_ss_sp == (unsigned long)ss_sp && |
|
t->sas_ss_size == ss_size && |
|
t->sas_ss_flags == ss_flags) |
|
return 0; |
|
|
|
sigaltstack_lock(); |
|
if (ss_mode == SS_DISABLE) { |
|
ss_size = 0; |
|
ss_sp = NULL; |
|
} else { |
|
if (unlikely(ss_size < min_ss_size)) |
|
ret = -ENOMEM; |
|
if (!sigaltstack_size_valid(ss_size)) |
|
ret = -ENOMEM; |
|
} |
|
if (!ret) { |
|
t->sas_ss_sp = (unsigned long) ss_sp; |
|
t->sas_ss_size = ss_size; |
|
t->sas_ss_flags = ss_flags; |
|
} |
|
sigaltstack_unlock(); |
|
} |
|
return ret; |
|
} |
|
|
|
SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
|
{ |
|
stack_t new, old; |
|
int err; |
|
if (uss && copy_from_user(&new, uss, sizeof(stack_t))) |
|
return -EFAULT; |
|
err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL, |
|
current_user_stack_pointer(), |
|
MINSIGSTKSZ); |
|
if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t))) |
|
err = -EFAULT; |
|
return err; |
|
} |
|
|
|
int restore_altstack(const stack_t __user *uss) |
|
{ |
|
stack_t new; |
|
if (copy_from_user(&new, uss, sizeof(stack_t))) |
|
return -EFAULT; |
|
(void)do_sigaltstack(&new, NULL, current_user_stack_pointer(), |
|
MINSIGSTKSZ); |
|
/* squash all but EFAULT for now */ |
|
return 0; |
|
} |
|
|
|
int __save_altstack(stack_t __user *uss, unsigned long sp) |
|
{ |
|
struct task_struct *t = current; |
|
int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
|
__put_user(t->sas_ss_flags, &uss->ss_flags) | |
|
__put_user(t->sas_ss_size, &uss->ss_size); |
|
return err; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr, |
|
compat_stack_t __user *uoss_ptr) |
|
{ |
|
stack_t uss, uoss; |
|
int ret; |
|
|
|
if (uss_ptr) { |
|
compat_stack_t uss32; |
|
if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) |
|
return -EFAULT; |
|
uss.ss_sp = compat_ptr(uss32.ss_sp); |
|
uss.ss_flags = uss32.ss_flags; |
|
uss.ss_size = uss32.ss_size; |
|
} |
|
ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, |
|
compat_user_stack_pointer(), |
|
COMPAT_MINSIGSTKSZ); |
|
if (ret >= 0 && uoss_ptr) { |
|
compat_stack_t old; |
|
memset(&old, 0, sizeof(old)); |
|
old.ss_sp = ptr_to_compat(uoss.ss_sp); |
|
old.ss_flags = uoss.ss_flags; |
|
old.ss_size = uoss.ss_size; |
|
if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t))) |
|
ret = -EFAULT; |
|
} |
|
return ret; |
|
} |
|
|
|
COMPAT_SYSCALL_DEFINE2(sigaltstack, |
|
const compat_stack_t __user *, uss_ptr, |
|
compat_stack_t __user *, uoss_ptr) |
|
{ |
|
return do_compat_sigaltstack(uss_ptr, uoss_ptr); |
|
} |
|
|
|
int compat_restore_altstack(const compat_stack_t __user *uss) |
|
{ |
|
int err = do_compat_sigaltstack(uss, NULL); |
|
/* squash all but -EFAULT for now */ |
|
return err == -EFAULT ? err : 0; |
|
} |
|
|
|
int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) |
|
{ |
|
int err; |
|
struct task_struct *t = current; |
|
err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), |
|
&uss->ss_sp) | |
|
__put_user(t->sas_ss_flags, &uss->ss_flags) | |
|
__put_user(t->sas_ss_size, &uss->ss_size); |
|
return err; |
|
} |
|
#endif |
|
|
|
#ifdef __ARCH_WANT_SYS_SIGPENDING |
|
|
|
/** |
|
* sys_sigpending - examine pending signals |
|
* @uset: where mask of pending signal is returned |
|
*/ |
|
SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset) |
|
{ |
|
sigset_t set; |
|
|
|
if (sizeof(old_sigset_t) > sizeof(*uset)) |
|
return -EINVAL; |
|
|
|
do_sigpending(&set); |
|
|
|
if (copy_to_user(uset, &set, sizeof(old_sigset_t))) |
|
return -EFAULT; |
|
|
|
return 0; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) |
|
{ |
|
sigset_t set; |
|
|
|
do_sigpending(&set); |
|
|
|
return put_user(set.sig[0], set32); |
|
} |
|
#endif |
|
|
|
#endif |
|
|
|
#ifdef __ARCH_WANT_SYS_SIGPROCMASK |
|
/** |
|
* sys_sigprocmask - examine and change blocked signals |
|
* @how: whether to add, remove, or set signals |
|
* @nset: signals to add or remove (if non-null) |
|
* @oset: previous value of signal mask if non-null |
|
* |
|
* Some platforms have their own version with special arguments; |
|
* others support only sys_rt_sigprocmask. |
|
*/ |
|
|
|
SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
|
old_sigset_t __user *, oset) |
|
{ |
|
old_sigset_t old_set, new_set; |
|
sigset_t new_blocked; |
|
|
|
old_set = current->blocked.sig[0]; |
|
|
|
if (nset) { |
|
if (copy_from_user(&new_set, nset, sizeof(*nset))) |
|
return -EFAULT; |
|
|
|
new_blocked = current->blocked; |
|
|
|
switch (how) { |
|
case SIG_BLOCK: |
|
sigaddsetmask(&new_blocked, new_set); |
|
break; |
|
case SIG_UNBLOCK: |
|
sigdelsetmask(&new_blocked, new_set); |
|
break; |
|
case SIG_SETMASK: |
|
new_blocked.sig[0] = new_set; |
|
break; |
|
default: |
|
return -EINVAL; |
|
} |
|
|
|
set_current_blocked(&new_blocked); |
|
} |
|
|
|
if (oset) { |
|
if (copy_to_user(oset, &old_set, sizeof(*oset))) |
|
return -EFAULT; |
|
} |
|
|
|
return 0; |
|
} |
|
#endif /* __ARCH_WANT_SYS_SIGPROCMASK */ |
|
|
|
#ifndef CONFIG_ODD_RT_SIGACTION |
|
/** |
|
* sys_rt_sigaction - alter an action taken by a process |
|
* @sig: signal to be sent |
|
* @act: new sigaction |
|
* @oact: used to save the previous sigaction |
|
* @sigsetsize: size of sigset_t type |
|
*/ |
|
SYSCALL_DEFINE4(rt_sigaction, int, sig, |
|
const struct sigaction __user *, act, |
|
struct sigaction __user *, oact, |
|
size_t, sigsetsize) |
|
{ |
|
struct k_sigaction new_sa, old_sa; |
|
int ret; |
|
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */ |
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) |
|
return -EFAULT; |
|
|
|
ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); |
|
if (ret) |
|
return ret; |
|
|
|
if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) |
|
return -EFAULT; |
|
|
|
return 0; |
|
} |
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
|
const struct compat_sigaction __user *, act, |
|
struct compat_sigaction __user *, oact, |
|
compat_size_t, sigsetsize) |
|
{ |
|
struct k_sigaction new_ka, old_ka; |
|
#ifdef __ARCH_HAS_SA_RESTORER |
|
compat_uptr_t restorer; |
|
#endif |
|
int ret; |
|
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */ |
|
if (sigsetsize != sizeof(compat_sigset_t)) |
|
return -EINVAL; |
|
|
|
if (act) { |
|
compat_uptr_t handler; |
|
ret = get_user(handler, &act->sa_handler); |
|
new_ka.sa.sa_handler = compat_ptr(handler); |
|
#ifdef __ARCH_HAS_SA_RESTORER |
|
ret |= get_user(restorer, &act->sa_restorer); |
|
new_ka.sa.sa_restorer = compat_ptr(restorer); |
|
#endif |
|
ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask); |
|
ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
|
if (ret) |
|
return -EFAULT; |
|
} |
|
|
|
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); |
|
if (!ret && oact) { |
|
ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), |
|
&oact->sa_handler); |
|
ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask, |
|
sizeof(oact->sa_mask)); |
|
ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
|
#ifdef __ARCH_HAS_SA_RESTORER |
|
ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), |
|
&oact->sa_restorer); |
|
#endif |
|
} |
|
return ret; |
|
} |
|
#endif |
|
#endif /* !CONFIG_ODD_RT_SIGACTION */ |
|
|
|
#ifdef CONFIG_OLD_SIGACTION |
|
SYSCALL_DEFINE3(sigaction, int, sig, |
|
const struct old_sigaction __user *, act, |
|
struct old_sigaction __user *, oact) |
|
{ |
|
struct k_sigaction new_ka, old_ka; |
|
int ret; |
|
|
|
if (act) { |
|
old_sigset_t mask; |
|
if (!access_ok(act, sizeof(*act)) || |
|
__get_user(new_ka.sa.sa_handler, &act->sa_handler) || |
|
__get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || |
|
__get_user(new_ka.sa.sa_flags, &act->sa_flags) || |
|
__get_user(mask, &act->sa_mask)) |
|
return -EFAULT; |
|
#ifdef __ARCH_HAS_KA_RESTORER |
|
new_ka.ka_restorer = NULL; |
|
#endif |
|
siginitset(&new_ka.sa.sa_mask, mask); |
|
} |
|
|
|
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); |
|
|
|
if (!ret && oact) { |
|
if (!access_ok(oact, sizeof(*oact)) || |
|
__put_user(old_ka.sa.sa_handler, &oact->sa_handler) || |
|
__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || |
|
__put_user(old_ka.sa.sa_flags, &oact->sa_flags) || |
|
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) |
|
return -EFAULT; |
|
} |
|
|
|
return ret; |
|
} |
|
#endif |
|
#ifdef CONFIG_COMPAT_OLD_SIGACTION |
|
COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, |
|
const struct compat_old_sigaction __user *, act, |
|
struct compat_old_sigaction __user *, oact) |
|
{ |
|
struct k_sigaction new_ka, old_ka; |
|
int ret; |
|
compat_old_sigset_t mask; |
|
compat_uptr_t handler, restorer; |
|
|
|
if (act) { |
|
if (!access_ok(act, sizeof(*act)) || |
|
__get_user(handler, &act->sa_handler) || |
|
__get_user(restorer, &act->sa_restorer) || |
|
__get_user(new_ka.sa.sa_flags, &act->sa_flags) || |
|
__get_user(mask, &act->sa_mask)) |
|
return -EFAULT; |
|
|
|
#ifdef __ARCH_HAS_KA_RESTORER |
|
new_ka.ka_restorer = NULL; |
|
#endif |
|
new_ka.sa.sa_handler = compat_ptr(handler); |
|
new_ka.sa.sa_restorer = compat_ptr(restorer); |
|
siginitset(&new_ka.sa.sa_mask, mask); |
|
} |
|
|
|
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); |
|
|
|
if (!ret && oact) { |
|
if (!access_ok(oact, sizeof(*oact)) || |
|
__put_user(ptr_to_compat(old_ka.sa.sa_handler), |
|
&oact->sa_handler) || |
|
__put_user(ptr_to_compat(old_ka.sa.sa_restorer), |
|
&oact->sa_restorer) || |
|
__put_user(old_ka.sa.sa_flags, &oact->sa_flags) || |
|
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) |
|
return -EFAULT; |
|
} |
|
return ret; |
|
} |
|
#endif |
|
|
|
#ifdef CONFIG_SGETMASK_SYSCALL |
|
|
|
/* |
|
* For backwards compatibility. Functionality superseded by sigprocmask. |
|
*/ |
|
SYSCALL_DEFINE0(sgetmask) |
|
{ |
|
/* SMP safe */ |
|
return current->blocked.sig[0]; |
|
} |
|
|
|
SYSCALL_DEFINE1(ssetmask, int, newmask) |
|
{ |
|
int old = current->blocked.sig[0]; |
|
sigset_t newset; |
|
|
|
siginitset(&newset, newmask); |
|
set_current_blocked(&newset); |
|
|
|
return old; |
|
} |
|
#endif /* CONFIG_SGETMASK_SYSCALL */ |
|
|
|
#ifdef __ARCH_WANT_SYS_SIGNAL |
|
/* |
|
* For backwards compatibility. Functionality superseded by sigaction. |
|
*/ |
|
SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
|
{ |
|
struct k_sigaction new_sa, old_sa; |
|
int ret; |
|
|
|
new_sa.sa.sa_handler = handler; |
|
new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; |
|
sigemptyset(&new_sa.sa.sa_mask); |
|
|
|
ret = do_sigaction(sig, &new_sa, &old_sa); |
|
|
|
return ret ? ret : (unsigned long)old_sa.sa.sa_handler; |
|
} |
|
#endif /* __ARCH_WANT_SYS_SIGNAL */ |
|
|
|
#ifdef __ARCH_WANT_SYS_PAUSE |
|
|
|
SYSCALL_DEFINE0(pause) |
|
{ |
|
while (!signal_pending(current)) { |
|
__set_current_state(TASK_INTERRUPTIBLE); |
|
schedule(); |
|
} |
|
return -ERESTARTNOHAND; |
|
} |
|
|
|
#endif |
|
|
|
static int sigsuspend(sigset_t *set) |
|
{ |
|
current->saved_sigmask = current->blocked; |
|
set_current_blocked(set); |
|
|
|
while (!signal_pending(current)) { |
|
__set_current_state(TASK_INTERRUPTIBLE); |
|
schedule(); |
|
} |
|
set_restore_sigmask(); |
|
return -ERESTARTNOHAND; |
|
} |
|
|
|
/** |
|
* sys_rt_sigsuspend - replace the signal mask for a value with the |
|
* @unewset value until a signal is received |
|
* @unewset: new signal mask value |
|
* @sigsetsize: size of sigset_t type |
|
*/ |
|
SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
|
{ |
|
sigset_t newset; |
|
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */ |
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
if (copy_from_user(&newset, unewset, sizeof(newset))) |
|
return -EFAULT; |
|
return sigsuspend(&newset); |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) |
|
{ |
|
sigset_t newset; |
|
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */ |
|
if (sigsetsize != sizeof(sigset_t)) |
|
return -EINVAL; |
|
|
|
if (get_compat_sigset(&newset, unewset)) |
|
return -EFAULT; |
|
return sigsuspend(&newset); |
|
} |
|
#endif |
|
|
|
#ifdef CONFIG_OLD_SIGSUSPEND |
|
SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) |
|
{ |
|
sigset_t blocked; |
|
siginitset(&blocked, mask); |
|
return sigsuspend(&blocked); |
|
} |
|
#endif |
|
#ifdef CONFIG_OLD_SIGSUSPEND3 |
|
SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) |
|
{ |
|
sigset_t blocked; |
|
siginitset(&blocked, mask); |
|
return sigsuspend(&blocked); |
|
} |
|
#endif |
|
|
|
__weak const char *arch_vma_name(struct vm_area_struct *vma) |
|
{ |
|
return NULL; |
|
} |
|
|
|
static inline void siginfo_buildtime_checks(void) |
|
{ |
|
BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE); |
|
|
|
/* Verify the offsets in the two siginfos match */ |
|
#define CHECK_OFFSET(field) \ |
|
BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field)) |
|
|
|
/* kill */ |
|
CHECK_OFFSET(si_pid); |
|
CHECK_OFFSET(si_uid); |
|
|
|
/* timer */ |
|
CHECK_OFFSET(si_tid); |
|
CHECK_OFFSET(si_overrun); |
|
CHECK_OFFSET(si_value); |
|
|
|
/* rt */ |
|
CHECK_OFFSET(si_pid); |
|
CHECK_OFFSET(si_uid); |
|
CHECK_OFFSET(si_value); |
|
|
|
/* sigchld */ |
|
CHECK_OFFSET(si_pid); |
|
CHECK_OFFSET(si_uid); |
|
CHECK_OFFSET(si_status); |
|
CHECK_OFFSET(si_utime); |
|
CHECK_OFFSET(si_stime); |
|
|
|
/* sigfault */ |
|
CHECK_OFFSET(si_addr); |
|
CHECK_OFFSET(si_trapno); |
|
CHECK_OFFSET(si_addr_lsb); |
|
CHECK_OFFSET(si_lower); |
|
CHECK_OFFSET(si_upper); |
|
CHECK_OFFSET(si_pkey); |
|
CHECK_OFFSET(si_perf_data); |
|
CHECK_OFFSET(si_perf_type); |
|
CHECK_OFFSET(si_perf_flags); |
|
|
|
/* sigpoll */ |
|
CHECK_OFFSET(si_band); |
|
CHECK_OFFSET(si_fd); |
|
|
|
/* sigsys */ |
|
CHECK_OFFSET(si_call_addr); |
|
CHECK_OFFSET(si_syscall); |
|
CHECK_OFFSET(si_arch); |
|
#undef CHECK_OFFSET |
|
|
|
/* usb asyncio */ |
|
BUILD_BUG_ON(offsetof(struct siginfo, si_pid) != |
|
offsetof(struct siginfo, si_addr)); |
|
if (sizeof(int) == sizeof(void __user *)) { |
|
BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) != |
|
sizeof(void __user *)); |
|
} else { |
|
BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) + |
|
sizeof_field(struct siginfo, si_uid)) != |
|
sizeof(void __user *)); |
|
BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) != |
|
offsetof(struct siginfo, si_uid)); |
|
} |
|
#ifdef CONFIG_COMPAT |
|
BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) != |
|
offsetof(struct compat_siginfo, si_addr)); |
|
BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) != |
|
sizeof(compat_uptr_t)); |
|
BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) != |
|
sizeof_field(struct siginfo, si_pid)); |
|
#endif |
|
} |
|
|
|
void __init signals_init(void) |
|
{ |
|
siginfo_buildtime_checks(); |
|
|
|
sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT); |
|
} |
|
|
|
#ifdef CONFIG_KGDB_KDB |
|
#include <linux/kdb.h> |
|
/* |
|
* kdb_send_sig - Allows kdb to send signals without exposing |
|
* signal internals. This function checks if the required locks are |
|
* available before calling the main signal code, to avoid kdb |
|
* deadlocks. |
|
*/ |
|
void kdb_send_sig(struct task_struct *t, int sig) |
|
{ |
|
static struct task_struct *kdb_prev_t; |
|
int new_t, ret; |
|
if (!spin_trylock(&t->sighand->siglock)) { |
|
kdb_printf("Can't do kill command now.\n" |
|
"The sigmask lock is held somewhere else in " |
|
"kernel, try again later\n"); |
|
return; |
|
} |
|
new_t = kdb_prev_t != t; |
|
kdb_prev_t = t; |
|
if (!task_is_running(t) && new_t) { |
|
spin_unlock(&t->sighand->siglock); |
|
kdb_printf("Process is not RUNNING, sending a signal from " |
|
"kdb risks deadlock\n" |
|
"on the run queue locks. " |
|
"The signal has _not_ been sent.\n" |
|
"Reissue the kill command if you want to risk " |
|
"the deadlock.\n"); |
|
return; |
|
} |
|
ret = send_signal_locked(sig, SEND_SIG_PRIV, t, PIDTYPE_PID); |
|
spin_unlock(&t->sighand->siglock); |
|
if (ret) |
|
kdb_printf("Fail to deliver Signal %d to process %d.\n", |
|
sig, t->pid); |
|
else |
|
kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); |
|
} |
|
#endif /* CONFIG_KGDB_KDB */
|
|
|