diff options
Diffstat (limited to 'kernel/itimer.c')
| -rw-r--r-- | kernel/itimer.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/kernel/itimer.c b/kernel/itimer.c new file mode 100644 index 0000000..6a5fe93 --- /dev/null +++ b/kernel/itimer.c @@ -0,0 +1,282 @@ +/* + * linux/kernel/itimer.c + * + * Copyright (C) 1992 Darren Senn + */ + +/* These are all the functions necessary to implement itimers */ + +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <linux/syscalls.h> +#include <linux/time.h> +#include <linux/posix-timers.h> +#include <linux/hrtimer.h> + +#include <asm/uaccess.h> + +/** + * itimer_get_remtime - get remaining time for the timer + * + * @timer: the timer to read + * + * Returns the delta between the expiry time and now, which can be + * less than zero or 1usec for an pending expired timer + */ +static struct timeval itimer_get_remtime(struct hrtimer *timer) +{ + ktime_t rem = hrtimer_get_remaining(timer); + + /* + * Racy but safe: if the itimer expires after the above + * hrtimer_get_remtime() call but before this condition + * then we return 0 - which is correct. + */ + if (hrtimer_active(timer)) { + if (rem.tv64 <= 0) + rem.tv64 = NSEC_PER_USEC; + } else + rem.tv64 = 0; + + return ktime_to_timeval(rem); +} + +int do_getitimer(int which, struct itimerval *value) +{ + struct task_struct *tsk = current; + cputime_t cinterval, cval; + + switch (which) { + case ITIMER_REAL: + spin_lock_irq(&tsk->sighand->siglock); + value->it_value = itimer_get_remtime(&tsk->signal->real_timer); + value->it_interval = + ktime_to_timeval(tsk->signal->it_real_incr); + spin_unlock_irq(&tsk->sighand->siglock); + break; + case ITIMER_VIRTUAL: + spin_lock_irq(&tsk->sighand->siglock); + cval = tsk->signal->it_virt_expires; + cinterval = tsk->signal->it_virt_incr; + if (!cputime_eq(cval, cputime_zero)) { + struct task_cputime cputime; + cputime_t utime; + + thread_group_cputime(tsk, &cputime); + utime = cputime.utime; + if (cputime_le(cval, utime)) { /* about to fire */ + cval = jiffies_to_cputime(1); + } else { + cval = cputime_sub(cval, utime); + } + } + spin_unlock_irq(&tsk->sighand->siglock); + cputime_to_timeval(cval, &value->it_value); + cputime_to_timeval(cinterval, &value->it_interval); + break; + case ITIMER_PROF: + spin_lock_irq(&tsk->sighand->siglock); + cval = tsk->signal->it_prof_expires; + cinterval = tsk->signal->it_prof_incr; + if (!cputime_eq(cval, cputime_zero)) { + struct task_cputime times; + cputime_t ptime; + + thread_group_cputime(tsk, ×); + ptime = cputime_add(times.utime, times.stime); + if (cputime_le(cval, ptime)) { /* about to fire */ + cval = jiffies_to_cputime(1); + } else { + cval = cputime_sub(cval, ptime); + } + } + spin_unlock_irq(&tsk->sighand->siglock); + cputime_to_timeval(cval, &value->it_value); + cputime_to_timeval(cinterval, &value->it_interval); + break; + default: + return(-EINVAL); + } + return 0; +} + +SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value) +{ + int error = -EFAULT; + struct itimerval get_buffer; + + if (value) { + error = do_getitimer(which, &get_buffer); + if (!error && + copy_to_user(value, &get_buffer, sizeof(get_buffer))) + error = -EFAULT; + } + return error; +} + + +/* + * The timer is automagically restarted, when interval != 0 + */ +enum hrtimer_restart it_real_fn(struct hrtimer *timer) +{ + struct signal_struct *sig = + container_of(timer, struct signal_struct, real_timer); + + kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid); + + return HRTIMER_NORESTART; +} + +/* + * Returns true if the timeval is in canonical form + */ +#define timeval_valid(t) \ + (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC)) + +int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) +{ + struct task_struct *tsk = current; + struct hrtimer *timer; + ktime_t expires; + cputime_t cval, cinterval, nval, ninterval; + + /* + * Validate the timevals in value. + */ + if (!timeval_valid(&value->it_value) || + !timeval_valid(&value->it_interval)) + return -EINVAL; + + switch (which) { + case ITIMER_REAL: +again: + spin_lock_irq(&tsk->sighand->siglock); + timer = &tsk->signal->real_timer; + if (ovalue) { + ovalue->it_value = itimer_get_remtime(timer); + ovalue->it_interval + = ktime_to_timeval(tsk->signal->it_real_incr); + } + /* We are sharing ->siglock with it_real_fn() */ + if (hrtimer_try_to_cancel(timer) < 0) { + spin_unlock_irq(&tsk->sighand->siglock); + goto again; + } + expires = timeval_to_ktime(value->it_value); + if (expires.tv64 != 0) { + tsk->signal->it_real_incr = + timeval_to_ktime(value->it_interval); + hrtimer_start(timer, expires, HRTIMER_MODE_REL); + } else + tsk->signal->it_real_incr.tv64 = 0; + + spin_unlock_irq(&tsk->sighand->siglock); + break; + case ITIMER_VIRTUAL: + nval = timeval_to_cputime(&value->it_value); + ninterval = timeval_to_cputime(&value->it_interval); + spin_lock_irq(&tsk->sighand->siglock); + cval = tsk->signal->it_virt_expires; + cinterval = tsk->signal->it_virt_incr; + if (!cputime_eq(cval, cputime_zero) || + !cputime_eq(nval, cputime_zero)) { + if (cputime_gt(nval, cputime_zero)) + nval = cputime_add(nval, + jiffies_to_cputime(1)); + set_process_cpu_timer(tsk, CPUCLOCK_VIRT, + &nval, &cval); + } + tsk->signal->it_virt_expires = nval; + tsk->signal->it_virt_incr = ninterval; + spin_unlock_irq(&tsk->sighand->siglock); + if (ovalue) { + cputime_to_timeval(cval, &ovalue->it_value); + cputime_to_timeval(cinterval, &ovalue->it_interval); + } + break; + case ITIMER_PROF: + nval = timeval_to_cputime(&value->it_value); + ninterval = timeval_to_cputime(&value->it_interval); + spin_lock_irq(&tsk->sighand->siglock); + cval = tsk->signal->it_prof_expires; + cinterval = tsk->signal->it_prof_incr; + if (!cputime_eq(cval, cputime_zero) || + !cputime_eq(nval, cputime_zero)) { + if (cputime_gt(nval, cputime_zero)) + nval = cputime_add(nval, + jiffies_to_cputime(1)); + set_process_cpu_timer(tsk, CPUCLOCK_PROF, + &nval, &cval); + } + tsk->signal->it_prof_expires = nval; + tsk->signal->it_prof_incr = ninterval; + spin_unlock_irq(&tsk->sighand->siglock); + if (ovalue) { + cputime_to_timeval(cval, &ovalue->it_value); + cputime_to_timeval(cinterval, &ovalue->it_interval); + } + break; + default: + return -EINVAL; + } + return 0; +} + +/** + * alarm_setitimer - set alarm in seconds + * + * @seconds: number of seconds until alarm + * 0 disables the alarm + * + * Returns the remaining time in seconds of a pending timer or 0 when + * the timer is not active. + * + * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid + * negative timeval settings which would cause immediate expiry. + */ +unsigned int alarm_setitimer(unsigned int seconds) +{ + struct itimerval it_new, it_old; + +#if BITS_PER_LONG < 64 + if (seconds > INT_MAX) + seconds = INT_MAX; +#endif + it_new.it_value.tv_sec = seconds; + it_new.it_value.tv_usec = 0; + it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; + + do_setitimer(ITIMER_REAL, &it_new, &it_old); + + /* + * We can't return 0 if we have an alarm pending ... And we'd + * better return too much than too little anyway + */ + if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) || + it_old.it_value.tv_usec >= 500000) + it_old.it_value.tv_sec++; + + return it_old.it_value.tv_sec; +} + +SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value, + struct itimerval __user *, ovalue) +{ + struct itimerval set_buffer, get_buffer; + int error; + + if (value) { + if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) + return -EFAULT; + } else + memset((char *) &set_buffer, 0, sizeof(set_buffer)); + + error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); + if (error || !ovalue) + return error; + + if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) + return -EFAULT; + return 0; +} |
