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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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/* 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/sched/signal.h>#include <linux/sched/cputime.h>#include <linux/posix-timers.h>#include <linux/hrtimer.h>#include <trace/events/timer.h>#include <linux/compat.h>
#include <linux/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 timespec64 itimer_get_remtime(struct hrtimer *timer){ ktime_t rem = __hrtimer_get_remaining(timer, true);
/* * 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 <= 0) rem = NSEC_PER_USEC; } else rem = 0;
return ktime_to_timespec64(rem);}
static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, struct itimerspec64 *const value){ u64 val, interval; struct cpu_itimer *it = &tsk->signal->it[clock_id];
spin_lock_irq(&tsk->sighand->siglock);
val = it->expires; interval = it->incr; if (val) { u64 t, samples[CPUCLOCK_MAX];
thread_group_sample_cputime(tsk, samples); t = samples[clock_id];
if (val < t) /* about to fire */ val = TICK_NSEC; else val -= t; }
spin_unlock_irq(&tsk->sighand->siglock);
value->it_value = ns_to_timespec64(val); value->it_interval = ns_to_timespec64(interval);}
static int do_getitimer(int which, struct itimerspec64 *value){ struct task_struct *tsk = current;
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_timespec64(tsk->signal->it_real_incr); spin_unlock_irq(&tsk->sighand->siglock); break; case ITIMER_VIRTUAL: get_cpu_itimer(tsk, CPUCLOCK_VIRT, value); break; case ITIMER_PROF: get_cpu_itimer(tsk, CPUCLOCK_PROF, value); break; default: return(-EINVAL); } return 0;}
static int put_itimerval(struct __kernel_old_itimerval __user *o, const struct itimerspec64 *i){ struct __kernel_old_itimerval v;
v.it_interval.tv_sec = i->it_interval.tv_sec; v.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC; v.it_value.tv_sec = i->it_value.tv_sec; v.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC; return copy_to_user(o, &v, sizeof(struct __kernel_old_itimerval)) ? -EFAULT : 0;}
SYSCALL_DEFINE2(getitimer, int, which, struct __kernel_old_itimerval __user *, value){ struct itimerspec64 get_buffer; int error = do_getitimer(which, &get_buffer);
if (!error && put_itimerval(value, &get_buffer)) error = -EFAULT; return error;}
#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)struct old_itimerval32 { struct old_timeval32 it_interval; struct old_timeval32 it_value;};
static int put_old_itimerval32(struct old_itimerval32 __user *o, const struct itimerspec64 *i){ struct old_itimerval32 v32;
v32.it_interval.tv_sec = i->it_interval.tv_sec; v32.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC; v32.it_value.tv_sec = i->it_value.tv_sec; v32.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC; return copy_to_user(o, &v32, sizeof(struct old_itimerval32)) ? -EFAULT : 0;}
COMPAT_SYSCALL_DEFINE2(getitimer, int, which, struct old_itimerval32 __user *, value){ struct itimerspec64 get_buffer; int error = do_getitimer(which, &get_buffer);
if (!error && put_old_itimerval32(value, &get_buffer)) error = -EFAULT; return error;}#endif
/* * Invoked from dequeue_signal() when SIG_ALRM is delivered. * * Restart the ITIMER_REAL timer if it is armed as periodic timer. Doing * this in the signal delivery path instead of self rearming prevents a DoS * with small increments in the high reolution timer case and reduces timer * noise in general. */void posixtimer_rearm_itimer(struct task_struct *tsk){ struct hrtimer *tmr = &tsk->signal->real_timer;
if (!hrtimer_is_queued(tmr) && tsk->signal->it_real_incr != 0) { hrtimer_forward_now(tmr, tsk->signal->it_real_incr); hrtimer_restart(tmr); }}
/* * Interval timers are restarted in the signal delivery path. See * posixtimer_rearm_itimer(). */enum hrtimer_restart it_real_fn(struct hrtimer *timer){ struct signal_struct *sig = container_of(timer, struct signal_struct, real_timer); struct pid *leader_pid = sig->pids[PIDTYPE_TGID];
trace_itimer_expire(ITIMER_REAL, leader_pid, 0); kill_pid_info(SIGALRM, SEND_SIG_PRIV, leader_pid);
return HRTIMER_NORESTART;}
static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, const struct itimerspec64 *const value, struct itimerspec64 *const ovalue){ u64 oval, nval, ointerval, ninterval; struct cpu_itimer *it = &tsk->signal->it[clock_id];
nval = timespec64_to_ns(&value->it_value); ninterval = timespec64_to_ns(&value->it_interval);
spin_lock_irq(&tsk->sighand->siglock);
oval = it->expires; ointerval = it->incr; if (oval || nval) { if (nval > 0) nval += TICK_NSEC; set_process_cpu_timer(tsk, clock_id, &nval, &oval); } it->expires = nval; it->incr = ninterval; trace_itimer_state(clock_id == CPUCLOCK_VIRT ? ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
spin_unlock_irq(&tsk->sighand->siglock);
if (ovalue) { ovalue->it_value = ns_to_timespec64(oval); ovalue->it_interval = ns_to_timespec64(ointerval); }}
/* * 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))
static int do_setitimer(int which, struct itimerspec64 *value, struct itimerspec64 *ovalue){ struct task_struct *tsk = current; struct hrtimer *timer; ktime_t expires;
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_timespec64(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); hrtimer_cancel_wait_running(timer); goto again; } expires = timespec64_to_ktime(value->it_value); if (expires != 0) { tsk->signal->it_real_incr = timespec64_to_ktime(value->it_interval); hrtimer_start(timer, expires, HRTIMER_MODE_REL); } else tsk->signal->it_real_incr = 0;
trace_itimer_state(ITIMER_REAL, value, 0); spin_unlock_irq(&tsk->sighand->siglock); break; case ITIMER_VIRTUAL: set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue); break; case ITIMER_PROF: set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue); break; default: return -EINVAL; } return 0;}
#ifdef CONFIG_SECURITY_SELINUXvoid clear_itimer(void){ struct itimerspec64 v = {}; int i;
for (i = 0; i < 3; i++) do_setitimer(i, &v, NULL);}#endif
#ifdef __ARCH_WANT_SYS_ALARM
/** * 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. */static unsigned int alarm_setitimer(unsigned int seconds){ struct itimerspec64 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_nsec = 0; it_new.it_interval.tv_sec = it_new.it_interval.tv_nsec = 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_nsec) || it_old.it_value.tv_nsec >= (NSEC_PER_SEC / 2)) it_old.it_value.tv_sec++;
return it_old.it_value.tv_sec;}
/* * For backwards compatibility? This can be done in libc so Alpha * and all newer ports shouldn't need it. */SYSCALL_DEFINE1(alarm, unsigned int, seconds){ return alarm_setitimer(seconds);}
#endif
static int get_itimerval(struct itimerspec64 *o, const struct __kernel_old_itimerval __user *i){ struct __kernel_old_itimerval v;
if (copy_from_user(&v, i, sizeof(struct __kernel_old_itimerval))) return -EFAULT;
/* Validate the timevals in value. */ if (!timeval_valid(&v.it_value) || !timeval_valid(&v.it_interval)) return -EINVAL;
o->it_interval.tv_sec = v.it_interval.tv_sec; o->it_interval.tv_nsec = v.it_interval.tv_usec * NSEC_PER_USEC; o->it_value.tv_sec = v.it_value.tv_sec; o->it_value.tv_nsec = v.it_value.tv_usec * NSEC_PER_USEC; return 0;}
SYSCALL_DEFINE3(setitimer, int, which, struct __kernel_old_itimerval __user *, value, struct __kernel_old_itimerval __user *, ovalue){ struct itimerspec64 set_buffer, get_buffer; int error;
if (value) { error = get_itimerval(&set_buffer, value); if (error) return error; } else { memset(&set_buffer, 0, sizeof(set_buffer)); printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer." " Misfeature support will be removed\n", current->comm); }
error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); if (error || !ovalue) return error;
if (put_itimerval(ovalue, &get_buffer)) return -EFAULT; return 0;}
#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)static int get_old_itimerval32(struct itimerspec64 *o, const struct old_itimerval32 __user *i){ struct old_itimerval32 v32;
if (copy_from_user(&v32, i, sizeof(struct old_itimerval32))) return -EFAULT;
/* Validate the timevals in value. */ if (!timeval_valid(&v32.it_value) || !timeval_valid(&v32.it_interval)) return -EINVAL;
o->it_interval.tv_sec = v32.it_interval.tv_sec; o->it_interval.tv_nsec = v32.it_interval.tv_usec * NSEC_PER_USEC; o->it_value.tv_sec = v32.it_value.tv_sec; o->it_value.tv_nsec = v32.it_value.tv_usec * NSEC_PER_USEC; return 0;}
COMPAT_SYSCALL_DEFINE3(setitimer, int, which, struct old_itimerval32 __user *, value, struct old_itimerval32 __user *, ovalue){ struct itimerspec64 set_buffer, get_buffer; int error;
if (value) { error = get_old_itimerval32(&set_buffer, value); if (error) return error; } else { memset(&set_buffer, 0, sizeof(set_buffer)); printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer." " Misfeature support will be removed\n", current->comm); }
error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); if (error || !ovalue) return error; if (put_old_itimerval32(ovalue, &get_buffer)) return -EFAULT; return 0;}#endif