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403 lines
10 KiB
403 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 1992 Darren Senn |
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*/ |
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/* These are all the functions necessary to implement itimers */ |
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#include <linux/mm.h> |
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#include <linux/interrupt.h> |
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#include <linux/syscalls.h> |
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#include <linux/time.h> |
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#include <linux/sched/signal.h> |
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#include <linux/sched/cputime.h> |
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#include <linux/posix-timers.h> |
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#include <linux/hrtimer.h> |
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#include <trace/events/timer.h> |
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#include <linux/compat.h> |
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#include <linux/uaccess.h> |
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/** |
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* itimer_get_remtime - get remaining time for the timer |
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* |
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* @timer: the timer to read |
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* |
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* Returns the delta between the expiry time and now, which can be |
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* less than zero or 1usec for an pending expired timer |
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*/ |
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static struct timespec64 itimer_get_remtime(struct hrtimer *timer) |
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{ |
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ktime_t rem = __hrtimer_get_remaining(timer, true); |
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/* |
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* Racy but safe: if the itimer expires after the above |
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* hrtimer_get_remtime() call but before this condition |
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* then we return 0 - which is correct. |
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*/ |
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if (hrtimer_active(timer)) { |
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if (rem <= 0) |
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rem = NSEC_PER_USEC; |
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} else |
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rem = 0; |
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return ktime_to_timespec64(rem); |
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} |
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static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, |
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struct itimerspec64 *const value) |
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{ |
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u64 val, interval; |
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struct cpu_itimer *it = &tsk->signal->it[clock_id]; |
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spin_lock_irq(&tsk->sighand->siglock); |
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val = it->expires; |
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interval = it->incr; |
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if (val) { |
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u64 t, samples[CPUCLOCK_MAX]; |
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thread_group_sample_cputime(tsk, samples); |
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t = samples[clock_id]; |
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if (val < t) |
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/* about to fire */ |
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val = TICK_NSEC; |
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else |
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val -= t; |
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} |
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spin_unlock_irq(&tsk->sighand->siglock); |
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value->it_value = ns_to_timespec64(val); |
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value->it_interval = ns_to_timespec64(interval); |
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} |
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static int do_getitimer(int which, struct itimerspec64 *value) |
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{ |
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struct task_struct *tsk = current; |
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switch (which) { |
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case ITIMER_REAL: |
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spin_lock_irq(&tsk->sighand->siglock); |
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value->it_value = itimer_get_remtime(&tsk->signal->real_timer); |
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value->it_interval = |
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ktime_to_timespec64(tsk->signal->it_real_incr); |
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spin_unlock_irq(&tsk->sighand->siglock); |
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break; |
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case ITIMER_VIRTUAL: |
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get_cpu_itimer(tsk, CPUCLOCK_VIRT, value); |
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break; |
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case ITIMER_PROF: |
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get_cpu_itimer(tsk, CPUCLOCK_PROF, value); |
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break; |
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default: |
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return(-EINVAL); |
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} |
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return 0; |
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} |
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static int put_itimerval(struct __kernel_old_itimerval __user *o, |
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const struct itimerspec64 *i) |
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{ |
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struct __kernel_old_itimerval v; |
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v.it_interval.tv_sec = i->it_interval.tv_sec; |
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v.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC; |
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v.it_value.tv_sec = i->it_value.tv_sec; |
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v.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC; |
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return copy_to_user(o, &v, sizeof(struct __kernel_old_itimerval)) ? -EFAULT : 0; |
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} |
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SYSCALL_DEFINE2(getitimer, int, which, struct __kernel_old_itimerval __user *, value) |
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{ |
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struct itimerspec64 get_buffer; |
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int error = do_getitimer(which, &get_buffer); |
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if (!error && put_itimerval(value, &get_buffer)) |
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error = -EFAULT; |
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return error; |
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} |
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#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA) |
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struct old_itimerval32 { |
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struct old_timeval32 it_interval; |
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struct old_timeval32 it_value; |
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}; |
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static int put_old_itimerval32(struct old_itimerval32 __user *o, |
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const struct itimerspec64 *i) |
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{ |
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struct old_itimerval32 v32; |
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v32.it_interval.tv_sec = i->it_interval.tv_sec; |
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v32.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC; |
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v32.it_value.tv_sec = i->it_value.tv_sec; |
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v32.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC; |
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return copy_to_user(o, &v32, sizeof(struct old_itimerval32)) ? -EFAULT : 0; |
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} |
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COMPAT_SYSCALL_DEFINE2(getitimer, int, which, |
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struct old_itimerval32 __user *, value) |
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{ |
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struct itimerspec64 get_buffer; |
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int error = do_getitimer(which, &get_buffer); |
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if (!error && put_old_itimerval32(value, &get_buffer)) |
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error = -EFAULT; |
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return error; |
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} |
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#endif |
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/* |
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* The timer is automagically restarted, when interval != 0 |
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*/ |
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enum hrtimer_restart it_real_fn(struct hrtimer *timer) |
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{ |
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struct signal_struct *sig = |
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container_of(timer, struct signal_struct, real_timer); |
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struct pid *leader_pid = sig->pids[PIDTYPE_TGID]; |
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trace_itimer_expire(ITIMER_REAL, leader_pid, 0); |
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kill_pid_info(SIGALRM, SEND_SIG_PRIV, leader_pid); |
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return HRTIMER_NORESTART; |
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} |
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static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, |
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const struct itimerspec64 *const value, |
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struct itimerspec64 *const ovalue) |
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{ |
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u64 oval, nval, ointerval, ninterval; |
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struct cpu_itimer *it = &tsk->signal->it[clock_id]; |
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nval = timespec64_to_ns(&value->it_value); |
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ninterval = timespec64_to_ns(&value->it_interval); |
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spin_lock_irq(&tsk->sighand->siglock); |
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oval = it->expires; |
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ointerval = it->incr; |
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if (oval || nval) { |
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if (nval > 0) |
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nval += TICK_NSEC; |
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set_process_cpu_timer(tsk, clock_id, &nval, &oval); |
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} |
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it->expires = nval; |
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it->incr = ninterval; |
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trace_itimer_state(clock_id == CPUCLOCK_VIRT ? |
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ITIMER_VIRTUAL : ITIMER_PROF, value, nval); |
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spin_unlock_irq(&tsk->sighand->siglock); |
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if (ovalue) { |
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ovalue->it_value = ns_to_timespec64(oval); |
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ovalue->it_interval = ns_to_timespec64(ointerval); |
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} |
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} |
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/* |
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* Returns true if the timeval is in canonical form |
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*/ |
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#define timeval_valid(t) \ |
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(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC)) |
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static int do_setitimer(int which, struct itimerspec64 *value, |
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struct itimerspec64 *ovalue) |
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{ |
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struct task_struct *tsk = current; |
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struct hrtimer *timer; |
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ktime_t expires; |
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switch (which) { |
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case ITIMER_REAL: |
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again: |
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spin_lock_irq(&tsk->sighand->siglock); |
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timer = &tsk->signal->real_timer; |
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if (ovalue) { |
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ovalue->it_value = itimer_get_remtime(timer); |
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ovalue->it_interval |
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= ktime_to_timespec64(tsk->signal->it_real_incr); |
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} |
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/* We are sharing ->siglock with it_real_fn() */ |
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if (hrtimer_try_to_cancel(timer) < 0) { |
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spin_unlock_irq(&tsk->sighand->siglock); |
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hrtimer_cancel_wait_running(timer); |
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goto again; |
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} |
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expires = timespec64_to_ktime(value->it_value); |
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if (expires != 0) { |
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tsk->signal->it_real_incr = |
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timespec64_to_ktime(value->it_interval); |
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hrtimer_start(timer, expires, HRTIMER_MODE_REL); |
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} else |
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tsk->signal->it_real_incr = 0; |
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trace_itimer_state(ITIMER_REAL, value, 0); |
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spin_unlock_irq(&tsk->sighand->siglock); |
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break; |
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case ITIMER_VIRTUAL: |
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set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue); |
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break; |
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case ITIMER_PROF: |
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set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue); |
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break; |
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default: |
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return -EINVAL; |
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} |
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return 0; |
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} |
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#ifdef CONFIG_SECURITY_SELINUX |
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void clear_itimer(void) |
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{ |
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struct itimerspec64 v = {}; |
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int i; |
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for (i = 0; i < 3; i++) |
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do_setitimer(i, &v, NULL); |
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} |
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#endif |
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#ifdef __ARCH_WANT_SYS_ALARM |
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/** |
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* alarm_setitimer - set alarm in seconds |
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* |
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* @seconds: number of seconds until alarm |
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* 0 disables the alarm |
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* |
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* Returns the remaining time in seconds of a pending timer or 0 when |
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* the timer is not active. |
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* |
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* On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid |
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* negative timeval settings which would cause immediate expiry. |
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*/ |
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static unsigned int alarm_setitimer(unsigned int seconds) |
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{ |
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struct itimerspec64 it_new, it_old; |
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#if BITS_PER_LONG < 64 |
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if (seconds > INT_MAX) |
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seconds = INT_MAX; |
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#endif |
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it_new.it_value.tv_sec = seconds; |
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it_new.it_value.tv_nsec = 0; |
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it_new.it_interval.tv_sec = it_new.it_interval.tv_nsec = 0; |
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do_setitimer(ITIMER_REAL, &it_new, &it_old); |
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/* |
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* We can't return 0 if we have an alarm pending ... And we'd |
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* better return too much than too little anyway |
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*/ |
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if ((!it_old.it_value.tv_sec && it_old.it_value.tv_nsec) || |
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it_old.it_value.tv_nsec >= (NSEC_PER_SEC / 2)) |
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it_old.it_value.tv_sec++; |
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return it_old.it_value.tv_sec; |
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} |
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/* |
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* For backwards compatibility? This can be done in libc so Alpha |
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* and all newer ports shouldn't need it. |
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*/ |
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SYSCALL_DEFINE1(alarm, unsigned int, seconds) |
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{ |
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return alarm_setitimer(seconds); |
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} |
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#endif |
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static int get_itimerval(struct itimerspec64 *o, const struct __kernel_old_itimerval __user *i) |
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{ |
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struct __kernel_old_itimerval v; |
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if (copy_from_user(&v, i, sizeof(struct __kernel_old_itimerval))) |
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return -EFAULT; |
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/* Validate the timevals in value. */ |
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if (!timeval_valid(&v.it_value) || |
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!timeval_valid(&v.it_interval)) |
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return -EINVAL; |
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o->it_interval.tv_sec = v.it_interval.tv_sec; |
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o->it_interval.tv_nsec = v.it_interval.tv_usec * NSEC_PER_USEC; |
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o->it_value.tv_sec = v.it_value.tv_sec; |
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o->it_value.tv_nsec = v.it_value.tv_usec * NSEC_PER_USEC; |
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return 0; |
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} |
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SYSCALL_DEFINE3(setitimer, int, which, struct __kernel_old_itimerval __user *, value, |
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struct __kernel_old_itimerval __user *, ovalue) |
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{ |
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struct itimerspec64 set_buffer, get_buffer; |
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int error; |
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if (value) { |
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error = get_itimerval(&set_buffer, value); |
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if (error) |
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return error; |
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} else { |
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memset(&set_buffer, 0, sizeof(set_buffer)); |
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printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer." |
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" Misfeature support will be removed\n", |
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current->comm); |
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} |
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error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); |
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if (error || !ovalue) |
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return error; |
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if (put_itimerval(ovalue, &get_buffer)) |
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return -EFAULT; |
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return 0; |
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} |
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#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA) |
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static int get_old_itimerval32(struct itimerspec64 *o, const struct old_itimerval32 __user *i) |
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{ |
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struct old_itimerval32 v32; |
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if (copy_from_user(&v32, i, sizeof(struct old_itimerval32))) |
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return -EFAULT; |
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/* Validate the timevals in value. */ |
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if (!timeval_valid(&v32.it_value) || |
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!timeval_valid(&v32.it_interval)) |
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return -EINVAL; |
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o->it_interval.tv_sec = v32.it_interval.tv_sec; |
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o->it_interval.tv_nsec = v32.it_interval.tv_usec * NSEC_PER_USEC; |
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o->it_value.tv_sec = v32.it_value.tv_sec; |
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o->it_value.tv_nsec = v32.it_value.tv_usec * NSEC_PER_USEC; |
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return 0; |
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} |
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COMPAT_SYSCALL_DEFINE3(setitimer, int, which, |
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struct old_itimerval32 __user *, value, |
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struct old_itimerval32 __user *, ovalue) |
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{ |
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struct itimerspec64 set_buffer, get_buffer; |
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int error; |
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if (value) { |
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error = get_old_itimerval32(&set_buffer, value); |
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if (error) |
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return error; |
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} else { |
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memset(&set_buffer, 0, sizeof(set_buffer)); |
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printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer." |
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" Misfeature support will be removed\n", |
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current->comm); |
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} |
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error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); |
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if (error || !ovalue) |
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return error; |
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if (put_old_itimerval32(ovalue, &get_buffer)) |
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return -EFAULT; |
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return 0; |
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} |
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#endif
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