mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
354 lines
8.7 KiB
354 lines
8.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* fs/signalfd.c |
|
* |
|
* Copyright (C) 2003 Linus Torvalds |
|
* |
|
* Mon Mar 5, 2007: Davide Libenzi <[email protected]> |
|
* Changed ->read() to return a siginfo strcture instead of signal number. |
|
* Fixed locking in ->poll(). |
|
* Added sighand-detach notification. |
|
* Added fd re-use in sys_signalfd() syscall. |
|
* Now using anonymous inode source. |
|
* Thanks to Oleg Nesterov for useful code review and suggestions. |
|
* More comments and suggestions from Arnd Bergmann. |
|
* Sat May 19, 2007: Davi E. M. Arnaut <[email protected]> |
|
* Retrieve multiple signals with one read() call |
|
* Sun Jul 15, 2007: Davide Libenzi <[email protected]> |
|
* Attach to the sighand only during read() and poll(). |
|
*/ |
|
|
|
#include <linux/file.h> |
|
#include <linux/poll.h> |
|
#include <linux/init.h> |
|
#include <linux/fs.h> |
|
#include <linux/sched.h> |
|
#include <linux/slab.h> |
|
#include <linux/kernel.h> |
|
#include <linux/signal.h> |
|
#include <linux/list.h> |
|
#include <linux/anon_inodes.h> |
|
#include <linux/signalfd.h> |
|
#include <linux/syscalls.h> |
|
#include <linux/proc_fs.h> |
|
#include <linux/compat.h> |
|
|
|
void signalfd_cleanup(struct sighand_struct *sighand) |
|
{ |
|
wake_up_pollfree(&sighand->signalfd_wqh); |
|
} |
|
|
|
struct signalfd_ctx { |
|
sigset_t sigmask; |
|
}; |
|
|
|
static int signalfd_release(struct inode *inode, struct file *file) |
|
{ |
|
kfree(file->private_data); |
|
return 0; |
|
} |
|
|
|
static __poll_t signalfd_poll(struct file *file, poll_table *wait) |
|
{ |
|
struct signalfd_ctx *ctx = file->private_data; |
|
__poll_t events = 0; |
|
|
|
poll_wait(file, ¤t->sighand->signalfd_wqh, wait); |
|
|
|
spin_lock_irq(¤t->sighand->siglock); |
|
if (next_signal(¤t->pending, &ctx->sigmask) || |
|
next_signal(¤t->signal->shared_pending, |
|
&ctx->sigmask)) |
|
events |= EPOLLIN; |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
|
|
return events; |
|
} |
|
|
|
/* |
|
* Copied from copy_siginfo_to_user() in kernel/signal.c |
|
*/ |
|
static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, |
|
kernel_siginfo_t const *kinfo) |
|
{ |
|
struct signalfd_siginfo new; |
|
|
|
BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128); |
|
|
|
/* |
|
* Unused members should be zero ... |
|
*/ |
|
memset(&new, 0, sizeof(new)); |
|
|
|
/* |
|
* If you change siginfo_t structure, please be sure |
|
* this code is fixed accordingly. |
|
*/ |
|
new.ssi_signo = kinfo->si_signo; |
|
new.ssi_errno = kinfo->si_errno; |
|
new.ssi_code = kinfo->si_code; |
|
switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) { |
|
case SIL_KILL: |
|
new.ssi_pid = kinfo->si_pid; |
|
new.ssi_uid = kinfo->si_uid; |
|
break; |
|
case SIL_TIMER: |
|
new.ssi_tid = kinfo->si_tid; |
|
new.ssi_overrun = kinfo->si_overrun; |
|
new.ssi_ptr = (long) kinfo->si_ptr; |
|
new.ssi_int = kinfo->si_int; |
|
break; |
|
case SIL_POLL: |
|
new.ssi_band = kinfo->si_band; |
|
new.ssi_fd = kinfo->si_fd; |
|
break; |
|
case SIL_FAULT_BNDERR: |
|
case SIL_FAULT_PKUERR: |
|
case SIL_FAULT_PERF_EVENT: |
|
/* |
|
* Fall through to the SIL_FAULT case. SIL_FAULT_BNDERR, |
|
* SIL_FAULT_PKUERR, and SIL_FAULT_PERF_EVENT are only |
|
* generated by faults that deliver them synchronously to |
|
* userspace. In case someone injects one of these signals |
|
* and signalfd catches it treat it as SIL_FAULT. |
|
*/ |
|
case SIL_FAULT: |
|
new.ssi_addr = (long) kinfo->si_addr; |
|
break; |
|
case SIL_FAULT_TRAPNO: |
|
new.ssi_addr = (long) kinfo->si_addr; |
|
new.ssi_trapno = kinfo->si_trapno; |
|
break; |
|
case SIL_FAULT_MCEERR: |
|
new.ssi_addr = (long) kinfo->si_addr; |
|
new.ssi_addr_lsb = (short) kinfo->si_addr_lsb; |
|
break; |
|
case SIL_CHLD: |
|
new.ssi_pid = kinfo->si_pid; |
|
new.ssi_uid = kinfo->si_uid; |
|
new.ssi_status = kinfo->si_status; |
|
new.ssi_utime = kinfo->si_utime; |
|
new.ssi_stime = kinfo->si_stime; |
|
break; |
|
case SIL_RT: |
|
/* |
|
* This case catches also the signals queued by sigqueue(). |
|
*/ |
|
new.ssi_pid = kinfo->si_pid; |
|
new.ssi_uid = kinfo->si_uid; |
|
new.ssi_ptr = (long) kinfo->si_ptr; |
|
new.ssi_int = kinfo->si_int; |
|
break; |
|
case SIL_SYS: |
|
new.ssi_call_addr = (long) kinfo->si_call_addr; |
|
new.ssi_syscall = kinfo->si_syscall; |
|
new.ssi_arch = kinfo->si_arch; |
|
break; |
|
} |
|
|
|
if (copy_to_user(uinfo, &new, sizeof(struct signalfd_siginfo))) |
|
return -EFAULT; |
|
|
|
return sizeof(*uinfo); |
|
} |
|
|
|
static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info, |
|
int nonblock) |
|
{ |
|
enum pid_type type; |
|
ssize_t ret; |
|
DECLARE_WAITQUEUE(wait, current); |
|
|
|
spin_lock_irq(¤t->sighand->siglock); |
|
ret = dequeue_signal(current, &ctx->sigmask, info, &type); |
|
switch (ret) { |
|
case 0: |
|
if (!nonblock) |
|
break; |
|
ret = -EAGAIN; |
|
fallthrough; |
|
default: |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
return ret; |
|
} |
|
|
|
add_wait_queue(¤t->sighand->signalfd_wqh, &wait); |
|
for (;;) { |
|
set_current_state(TASK_INTERRUPTIBLE); |
|
ret = dequeue_signal(current, &ctx->sigmask, info, &type); |
|
if (ret != 0) |
|
break; |
|
if (signal_pending(current)) { |
|
ret = -ERESTARTSYS; |
|
break; |
|
} |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
schedule(); |
|
spin_lock_irq(¤t->sighand->siglock); |
|
} |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
|
|
remove_wait_queue(¤t->sighand->signalfd_wqh, &wait); |
|
__set_current_state(TASK_RUNNING); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* Returns a multiple of the size of a "struct signalfd_siginfo", or a negative |
|
* error code. The "count" parameter must be at least the size of a |
|
* "struct signalfd_siginfo". |
|
*/ |
|
static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count, |
|
loff_t *ppos) |
|
{ |
|
struct signalfd_ctx *ctx = file->private_data; |
|
struct signalfd_siginfo __user *siginfo; |
|
int nonblock = file->f_flags & O_NONBLOCK; |
|
ssize_t ret, total = 0; |
|
kernel_siginfo_t info; |
|
|
|
count /= sizeof(struct signalfd_siginfo); |
|
if (!count) |
|
return -EINVAL; |
|
|
|
siginfo = (struct signalfd_siginfo __user *) buf; |
|
do { |
|
ret = signalfd_dequeue(ctx, &info, nonblock); |
|
if (unlikely(ret <= 0)) |
|
break; |
|
ret = signalfd_copyinfo(siginfo, &info); |
|
if (ret < 0) |
|
break; |
|
siginfo++; |
|
total += ret; |
|
nonblock = 1; |
|
} while (--count); |
|
|
|
return total ? total: ret; |
|
} |
|
|
|
#ifdef CONFIG_PROC_FS |
|
static void signalfd_show_fdinfo(struct seq_file *m, struct file *f) |
|
{ |
|
struct signalfd_ctx *ctx = f->private_data; |
|
sigset_t sigmask; |
|
|
|
sigmask = ctx->sigmask; |
|
signotset(&sigmask); |
|
render_sigset_t(m, "sigmask:\t", &sigmask); |
|
} |
|
#endif |
|
|
|
static const struct file_operations signalfd_fops = { |
|
#ifdef CONFIG_PROC_FS |
|
.show_fdinfo = signalfd_show_fdinfo, |
|
#endif |
|
.release = signalfd_release, |
|
.poll = signalfd_poll, |
|
.read = signalfd_read, |
|
.llseek = noop_llseek, |
|
}; |
|
|
|
static int do_signalfd4(int ufd, sigset_t *mask, int flags) |
|
{ |
|
struct signalfd_ctx *ctx; |
|
|
|
/* Check the SFD_* constants for consistency. */ |
|
BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC); |
|
BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK); |
|
|
|
if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK)) |
|
return -EINVAL; |
|
|
|
sigdelsetmask(mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
|
signotset(mask); |
|
|
|
if (ufd == -1) { |
|
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); |
|
if (!ctx) |
|
return -ENOMEM; |
|
|
|
ctx->sigmask = *mask; |
|
|
|
/* |
|
* When we call this, the initialization must be complete, since |
|
* anon_inode_getfd() will install the fd. |
|
*/ |
|
ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx, |
|
O_RDWR | (flags & (O_CLOEXEC | O_NONBLOCK))); |
|
if (ufd < 0) |
|
kfree(ctx); |
|
} else { |
|
struct fd f = fdget(ufd); |
|
if (!f.file) |
|
return -EBADF; |
|
ctx = f.file->private_data; |
|
if (f.file->f_op != &signalfd_fops) { |
|
fdput(f); |
|
return -EINVAL; |
|
} |
|
spin_lock_irq(¤t->sighand->siglock); |
|
ctx->sigmask = *mask; |
|
spin_unlock_irq(¤t->sighand->siglock); |
|
|
|
wake_up(¤t->sighand->signalfd_wqh); |
|
fdput(f); |
|
} |
|
|
|
return ufd; |
|
} |
|
|
|
SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask, |
|
size_t, sizemask, int, flags) |
|
{ |
|
sigset_t mask; |
|
|
|
if (sizemask != sizeof(sigset_t)) |
|
return -EINVAL; |
|
if (copy_from_user(&mask, user_mask, sizeof(mask))) |
|
return -EFAULT; |
|
return do_signalfd4(ufd, &mask, flags); |
|
} |
|
|
|
SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask, |
|
size_t, sizemask) |
|
{ |
|
sigset_t mask; |
|
|
|
if (sizemask != sizeof(sigset_t)) |
|
return -EINVAL; |
|
if (copy_from_user(&mask, user_mask, sizeof(mask))) |
|
return -EFAULT; |
|
return do_signalfd4(ufd, &mask, 0); |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
static long do_compat_signalfd4(int ufd, |
|
const compat_sigset_t __user *user_mask, |
|
compat_size_t sigsetsize, int flags) |
|
{ |
|
sigset_t mask; |
|
|
|
if (sigsetsize != sizeof(compat_sigset_t)) |
|
return -EINVAL; |
|
if (get_compat_sigset(&mask, user_mask)) |
|
return -EFAULT; |
|
return do_signalfd4(ufd, &mask, flags); |
|
} |
|
|
|
COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd, |
|
const compat_sigset_t __user *, user_mask, |
|
compat_size_t, sigsetsize, |
|
int, flags) |
|
{ |
|
return do_compat_signalfd4(ufd, user_mask, sigsetsize, flags); |
|
} |
|
|
|
COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd, |
|
const compat_sigset_t __user *, user_mask, |
|
compat_size_t, sigsetsize) |
|
{ |
|
return do_compat_signalfd4(ufd, user_mask, sigsetsize, 0); |
|
} |
|
#endif
|
|
|