250 строки
6.6 KiB
C
250 строки
6.6 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/smp_lock.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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int it_real_fn(void *data)
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{
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struct task_struct *tsk = (struct task_struct *) data;
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send_group_sig_info(SIGALRM, SEND_SIG_PRIV, tsk);
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if (tsk->signal->it_real_incr.tv64 != 0) {
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hrtimer_forward(&tsk->signal->real_timer,
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tsk->signal->it_real_incr);
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return HRTIMER_RESTART;
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}
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return HRTIMER_NORESTART;
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}
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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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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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tsk->signal->it_real_incr =
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timeval_to_ktime(value->it_interval);
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expires = timeval_to_ktime(value->it_value);
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if (expires.tv64 != 0)
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hrtimer_start(timer, expires, HRTIMER_REL);
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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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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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