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![Oleg Nesterov](/assets/img/avatar_default.png)
signal_struct->tsk points to the ->group_leader and thus we have the nasty code in de_thread() which has to change it and restart ->real_timer if the leader is changed. Use "struct pid *leader_pid" instead. This also allows us to kill now unneeded send_group_sig_info(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Pavel Emelyanov <xemul@openvz.org> Acked-by: Roland McGrath <roland@redhat.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
296 lines
7.8 KiB
C
296 lines
7.8 KiB
C
/*
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* linux/kernel/itimer.c
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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/posix-timers.h>
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#include <linux/hrtimer.h>
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#include <asm/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 timeval itimer_get_remtime(struct hrtimer *timer)
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{
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ktime_t rem = hrtimer_get_remaining(timer);
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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.tv64 <= 0)
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rem.tv64 = NSEC_PER_USEC;
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} else
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rem.tv64 = 0;
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return ktime_to_timeval(rem);
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}
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int do_getitimer(int which, struct itimerval *value)
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{
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struct task_struct *tsk = current;
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cputime_t cinterval, cval;
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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_timeval(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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read_lock(&tasklist_lock);
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spin_lock_irq(&tsk->sighand->siglock);
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cval = tsk->signal->it_virt_expires;
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cinterval = tsk->signal->it_virt_incr;
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if (!cputime_eq(cval, cputime_zero)) {
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struct task_struct *t = tsk;
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cputime_t utime = tsk->signal->utime;
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do {
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utime = cputime_add(utime, t->utime);
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t = next_thread(t);
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} while (t != tsk);
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if (cputime_le(cval, utime)) { /* about to fire */
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cval = jiffies_to_cputime(1);
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} else {
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cval = cputime_sub(cval, utime);
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}
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}
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spin_unlock_irq(&tsk->sighand->siglock);
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read_unlock(&tasklist_lock);
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cputime_to_timeval(cval, &value->it_value);
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cputime_to_timeval(cinterval, &value->it_interval);
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break;
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case ITIMER_PROF:
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read_lock(&tasklist_lock);
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spin_lock_irq(&tsk->sighand->siglock);
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cval = tsk->signal->it_prof_expires;
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cinterval = tsk->signal->it_prof_incr;
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if (!cputime_eq(cval, cputime_zero)) {
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struct task_struct *t = tsk;
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cputime_t ptime = cputime_add(tsk->signal->utime,
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tsk->signal->stime);
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do {
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ptime = cputime_add(ptime,
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cputime_add(t->utime,
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t->stime));
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t = next_thread(t);
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} while (t != tsk);
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if (cputime_le(cval, ptime)) { /* about to fire */
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cval = jiffies_to_cputime(1);
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} else {
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cval = cputime_sub(cval, ptime);
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}
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}
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spin_unlock_irq(&tsk->sighand->siglock);
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read_unlock(&tasklist_lock);
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cputime_to_timeval(cval, &value->it_value);
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cputime_to_timeval(cinterval, &value->it_interval);
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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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asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
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{
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int error = -EFAULT;
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struct itimerval get_buffer;
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if (value) {
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error = do_getitimer(which, &get_buffer);
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if (!error &&
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copy_to_user(value, &get_buffer, sizeof(get_buffer)))
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error = -EFAULT;
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}
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return error;
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}
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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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kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
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return HRTIMER_NORESTART;
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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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int do_setitimer(int which, struct itimerval *value, struct itimerval *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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cputime_t cval, cinterval, nval, ninterval;
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/*
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* Validate the timevals in value.
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*/
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if (!timeval_valid(&value->it_value) ||
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!timeval_valid(&value->it_interval))
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return -EINVAL;
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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_timeval(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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goto again;
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}
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expires = timeval_to_ktime(value->it_value);
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if (expires.tv64 != 0) {
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tsk->signal->it_real_incr =
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timeval_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.tv64 = 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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nval = timeval_to_cputime(&value->it_value);
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ninterval = timeval_to_cputime(&value->it_interval);
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read_lock(&tasklist_lock);
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spin_lock_irq(&tsk->sighand->siglock);
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cval = tsk->signal->it_virt_expires;
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cinterval = tsk->signal->it_virt_incr;
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if (!cputime_eq(cval, cputime_zero) ||
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!cputime_eq(nval, cputime_zero)) {
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if (cputime_gt(nval, cputime_zero))
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nval = cputime_add(nval,
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jiffies_to_cputime(1));
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set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
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&nval, &cval);
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}
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tsk->signal->it_virt_expires = nval;
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tsk->signal->it_virt_incr = ninterval;
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spin_unlock_irq(&tsk->sighand->siglock);
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read_unlock(&tasklist_lock);
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if (ovalue) {
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cputime_to_timeval(cval, &ovalue->it_value);
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cputime_to_timeval(cinterval, &ovalue->it_interval);
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}
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break;
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case ITIMER_PROF:
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nval = timeval_to_cputime(&value->it_value);
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ninterval = timeval_to_cputime(&value->it_interval);
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read_lock(&tasklist_lock);
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spin_lock_irq(&tsk->sighand->siglock);
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cval = tsk->signal->it_prof_expires;
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cinterval = tsk->signal->it_prof_incr;
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if (!cputime_eq(cval, cputime_zero) ||
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!cputime_eq(nval, cputime_zero)) {
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if (cputime_gt(nval, cputime_zero))
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nval = cputime_add(nval,
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jiffies_to_cputime(1));
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set_process_cpu_timer(tsk, CPUCLOCK_PROF,
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&nval, &cval);
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}
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tsk->signal->it_prof_expires = nval;
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tsk->signal->it_prof_incr = ninterval;
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spin_unlock_irq(&tsk->sighand->siglock);
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read_unlock(&tasklist_lock);
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if (ovalue) {
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cputime_to_timeval(cval, &ovalue->it_value);
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cputime_to_timeval(cinterval, &ovalue->it_interval);
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}
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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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/**
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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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unsigned int alarm_setitimer(unsigned int seconds)
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{
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struct itimerval 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_usec = 0;
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it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 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_usec) ||
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it_old.it_value.tv_usec >= 500000)
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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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asmlinkage long sys_setitimer(int which,
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struct itimerval __user *value,
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struct itimerval __user *ovalue)
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{
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struct itimerval set_buffer, get_buffer;
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int error;
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if (value) {
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if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
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return -EFAULT;
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} else
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memset((char *) &set_buffer, 0, sizeof(set_buffer));
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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 (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
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return -EFAULT;
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return 0;
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}
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