diff options
Diffstat (limited to 'kernel/itimer.c')
| -rw-r--r-- | kernel/itimer.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/kernel/itimer.c b/kernel/itimer.c new file mode 100644 index 00000000000..e9a40e947e0 --- /dev/null +++ b/kernel/itimer.c @@ -0,0 +1,241 @@ +/* + * linux/kernel/itimer.c + * + * Copyright (C) 1992 Darren Senn + */ + +/* These are all the functions necessary to implement itimers */ + +#include <linux/mm.h> +#include <linux/smp_lock.h> +#include <linux/interrupt.h> +#include <linux/syscalls.h> +#include <linux/time.h> +#include <linux/posix-timers.h> + +#include <asm/uaccess.h> + +static unsigned long it_real_value(struct signal_struct *sig) +{ + unsigned long val = 0; + if (timer_pending(&sig->real_timer)) { + val = sig->real_timer.expires - jiffies; + + /* look out for negative/zero itimer.. */ + if ((long) val <= 0) + val = 1; + } + return val; +} + +int do_getitimer(int which, struct itimerval *value) +{ + struct task_struct *tsk = current; + unsigned long interval, val; + cputime_t cinterval, cval; + + switch (which) { + case ITIMER_REAL: + spin_lock_irq(&tsk->sighand->siglock); + interval = tsk->signal->it_real_incr; + val = it_real_value(tsk->signal); + spin_unlock_irq(&tsk->sighand->siglock); + jiffies_to_timeval(val, &value->it_value); + jiffies_to_timeval(interval, &value->it_interval); + break; + case ITIMER_VIRTUAL: + read_lock(&tasklist_lock); + 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_struct *t = tsk; + cputime_t utime = tsk->signal->utime; + do { + utime = cputime_add(utime, t->utime); + t = next_thread(t); + } while (t != tsk); + 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); + read_unlock(&tasklist_lock); + cputime_to_timeval(cval, &value->it_value); + cputime_to_timeval(cinterval, &value->it_interval); + break; + case ITIMER_PROF: + read_lock(&tasklist_lock); + 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_struct *t = tsk; + cputime_t ptime = cputime_add(tsk->signal->utime, + tsk->signal->stime); + do { + ptime = cputime_add(ptime, + cputime_add(t->utime, + t->stime)); + t = next_thread(t); + } while (t != tsk); + 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); + read_unlock(&tasklist_lock); + cputime_to_timeval(cval, &value->it_value); + cputime_to_timeval(cinterval, &value->it_interval); + break; + default: + return(-EINVAL); + } + return 0; +} + +asmlinkage long sys_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; +} + +/* + * Called with P->sighand->siglock held and P->signal->real_timer inactive. + * If interval is nonzero, arm the timer for interval ticks from now. + */ +static inline void it_real_arm(struct task_struct *p, unsigned long interval) +{ + p->signal->it_real_value = interval; /* XXX unnecessary field?? */ + if (interval == 0) + return; + if (interval > (unsigned long) LONG_MAX) + interval = LONG_MAX; + p->signal->real_timer.expires = jiffies + interval; + add_timer(&p->signal->real_timer); +} + +void it_real_fn(unsigned long __data) +{ + struct task_struct * p = (struct task_struct *) __data; + + send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p); + + /* + * Now restart the timer if necessary. We don't need any locking + * here because do_setitimer makes sure we have finished running + * before it touches anything. + */ + it_real_arm(p, p->signal->it_real_incr); +} + +int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) +{ + struct task_struct *tsk = current; + unsigned long val, interval; + cputime_t cval, cinterval, nval, ninterval; + + switch (which) { + case ITIMER_REAL: + spin_lock_irq(&tsk->sighand->siglock); + interval = tsk->signal->it_real_incr; + val = it_real_value(tsk->signal); + if (val) + del_timer_sync(&tsk->signal->real_timer); + tsk->signal->it_real_incr = + timeval_to_jiffies(&value->it_interval); + it_real_arm(tsk, timeval_to_jiffies(&value->it_value)); + spin_unlock_irq(&tsk->sighand->siglock); + if (ovalue) { + jiffies_to_timeval(val, &ovalue->it_value); + jiffies_to_timeval(interval, + &ovalue->it_interval); + } + break; + case ITIMER_VIRTUAL: + nval = timeval_to_cputime(&value->it_value); + ninterval = timeval_to_cputime(&value->it_interval); + read_lock(&tasklist_lock); + 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); + read_unlock(&tasklist_lock); + 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); + read_lock(&tasklist_lock); + 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); + read_unlock(&tasklist_lock); + if (ovalue) { + cputime_to_timeval(cval, &ovalue->it_value); + cputime_to_timeval(cinterval, &ovalue->it_interval); + } + break; + default: + return -EINVAL; + } + return 0; +} + +asmlinkage long sys_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; +} |