250 строки
6.9 KiB
C
250 строки
6.9 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 <asm/uaccess.h>
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static unsigned long it_real_value(struct signal_struct *sig)
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{
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unsigned long val = 0;
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if (timer_pending(&sig->real_timer)) {
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val = sig->real_timer.expires - jiffies;
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/* look out for negative/zero itimer.. */
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if ((long) val <= 0)
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val = 1;
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}
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return val;
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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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unsigned long interval, val;
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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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interval = tsk->signal->it_real_incr;
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val = it_real_value(tsk->signal);
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spin_unlock_irq(&tsk->sighand->siglock);
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jiffies_to_timeval(val, &value->it_value);
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jiffies_to_timeval(interval, &value->it_interval);
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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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* Called with P->sighand->siglock held and P->signal->real_timer inactive.
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* If interval is nonzero, arm the timer for interval ticks from now.
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*/
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static inline void it_real_arm(struct task_struct *p, unsigned long interval)
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{
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p->signal->it_real_value = interval; /* XXX unnecessary field?? */
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if (interval == 0)
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return;
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if (interval > (unsigned long) LONG_MAX)
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interval = LONG_MAX;
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/* the "+ 1" below makes sure that the timer doesn't go off before
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* the interval requested. This could happen if
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* time requested % (usecs per jiffy) is more than the usecs left
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* in the current jiffy */
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p->signal->real_timer.expires = jiffies + interval + 1;
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add_timer(&p->signal->real_timer);
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}
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void it_real_fn(unsigned long __data)
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{
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struct task_struct * p = (struct task_struct *) __data;
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send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p);
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/*
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* Now restart the timer if necessary. We don't need any locking
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* here because do_setitimer makes sure we have finished running
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* before it touches anything.
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*/
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it_real_arm(p, p->signal->it_real_incr);
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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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unsigned long val, interval;
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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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interval = tsk->signal->it_real_incr;
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val = it_real_value(tsk->signal);
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/* We are sharing ->siglock with it_real_fn() */
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if (try_to_del_timer_sync(&tsk->signal->real_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_jiffies(&value->it_interval);
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it_real_arm(tsk, timeval_to_jiffies(&value->it_value));
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spin_unlock_irq(&tsk->sighand->siglock);
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if (ovalue) {
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jiffies_to_timeval(val, &ovalue->it_value);
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jiffies_to_timeval(interval,
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&ovalue->it_interval);
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}
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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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