2 * linux/kernel/itimer.c
4 * Copyright (C) 1992 Darren Senn
7 /* These are all the functions necessary to implement itimers */
10 #include <linux/smp_lock.h>
11 #include <linux/interrupt.h>
12 #include <linux/syscalls.h>
13 #include <linux/time.h>
14 #include <linux/posix-timers.h>
15 #include <linux/hrtimer.h>
17 #include <asm/uaccess.h>
20 * itimer_get_remtime - get remaining time for the timer
22 * @timer: the timer to read
24 * Returns the delta between the expiry time and now, which can be
25 * less than zero or 1usec for an pending expired timer
27 static struct timeval
itimer_get_remtime(struct hrtimer
*timer
)
29 ktime_t rem
= hrtimer_get_remaining(timer
);
32 * Racy but safe: if the itimer expires after the above
33 * hrtimer_get_remtime() call but before this condition
34 * then we return 0 - which is correct.
36 if (hrtimer_active(timer
)) {
38 rem
.tv64
= NSEC_PER_USEC
;
42 return ktime_to_timeval(rem
);
45 int do_getitimer(int which
, struct itimerval
*value
)
47 struct task_struct
*tsk
= current
;
48 cputime_t cinterval
, cval
;
52 spin_lock_irq(&tsk
->sighand
->siglock
);
53 value
->it_value
= itimer_get_remtime(&tsk
->signal
->real_timer
);
55 ktime_to_timeval(tsk
->signal
->it_real_incr
);
56 spin_unlock_irq(&tsk
->sighand
->siglock
);
59 read_lock(&tasklist_lock
);
60 spin_lock_irq(&tsk
->sighand
->siglock
);
61 cval
= tsk
->signal
->it_virt_expires
;
62 cinterval
= tsk
->signal
->it_virt_incr
;
63 if (!cputime_eq(cval
, cputime_zero
)) {
64 struct task_struct
*t
= tsk
;
65 cputime_t utime
= tsk
->signal
->utime
;
67 utime
= cputime_add(utime
, t
->utime
);
70 if (cputime_le(cval
, utime
)) { /* about to fire */
71 cval
= jiffies_to_cputime(1);
73 cval
= cputime_sub(cval
, utime
);
76 spin_unlock_irq(&tsk
->sighand
->siglock
);
77 read_unlock(&tasklist_lock
);
78 cputime_to_timeval(cval
, &value
->it_value
);
79 cputime_to_timeval(cinterval
, &value
->it_interval
);
82 read_lock(&tasklist_lock
);
83 spin_lock_irq(&tsk
->sighand
->siglock
);
84 cval
= tsk
->signal
->it_prof_expires
;
85 cinterval
= tsk
->signal
->it_prof_incr
;
86 if (!cputime_eq(cval
, cputime_zero
)) {
87 struct task_struct
*t
= tsk
;
88 cputime_t ptime
= cputime_add(tsk
->signal
->utime
,
91 ptime
= cputime_add(ptime
,
96 if (cputime_le(cval
, ptime
)) { /* about to fire */
97 cval
= jiffies_to_cputime(1);
99 cval
= cputime_sub(cval
, ptime
);
102 spin_unlock_irq(&tsk
->sighand
->siglock
);
103 read_unlock(&tasklist_lock
);
104 cputime_to_timeval(cval
, &value
->it_value
);
105 cputime_to_timeval(cinterval
, &value
->it_interval
);
113 asmlinkage
long sys_getitimer(int which
, struct itimerval __user
*value
)
116 struct itimerval get_buffer
;
119 error
= do_getitimer(which
, &get_buffer
);
121 copy_to_user(value
, &get_buffer
, sizeof(get_buffer
)))
129 * The timer is automagically restarted, when interval != 0
131 enum hrtimer_restart
it_real_fn(struct hrtimer
*timer
)
133 struct signal_struct
*sig
=
134 container_of(timer
, struct signal_struct
, real_timer
);
136 send_group_sig_info(SIGALRM
, SEND_SIG_PRIV
, sig
->tsk
);
138 return HRTIMER_NORESTART
;
142 * We do not care about correctness. We just sanitize the values so
143 * the ktime_t operations which expect normalized values do not
144 * break. This converts negative values to long timeouts similar to
145 * the code in kernel versions < 2.6.16
147 * Print a limited number of warning messages when an invalid timeval
150 static void fixup_timeval(struct timeval
*tv
, int interval
)
152 static int warnlimit
= 10;
158 "setitimer: %s (pid = %d) provided "
159 "invalid timeval %s: tv_sec = %ld tv_usec = %ld\n",
160 current
->comm
, current
->pid
,
161 interval
? "it_interval" : "it_value",
162 tv
->tv_sec
, (long) tv
->tv_usec
);
166 if (tmp
>= USEC_PER_SEC
) {
167 tv
->tv_usec
= tmp
% USEC_PER_SEC
;
168 tv
->tv_sec
+= tmp
/ USEC_PER_SEC
;
173 tv
->tv_sec
= LONG_MAX
;
177 * Returns true if the timeval is in canonical form
179 #define timeval_valid(t) \
180 (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
183 * Check for invalid timevals, sanitize them and print a limited
184 * number of warnings.
186 static void check_itimerval(struct itimerval
*value
) {
188 if (unlikely(!timeval_valid(&value
->it_value
)))
189 fixup_timeval(&value
->it_value
, 0);
191 if (unlikely(!timeval_valid(&value
->it_interval
)))
192 fixup_timeval(&value
->it_interval
, 1);
195 int do_setitimer(int which
, struct itimerval
*value
, struct itimerval
*ovalue
)
197 struct task_struct
*tsk
= current
;
198 struct hrtimer
*timer
;
200 cputime_t cval
, cinterval
, nval
, ninterval
;
203 * Validate the timevals in value.
205 * Note: Although the spec requires that invalid values shall
206 * return -EINVAL, we just fixup the value and print a limited
207 * number of warnings in order not to break users of this
208 * historical misfeature.
210 * Scheduled for replacement in March 2007
212 check_itimerval(value
);
217 spin_lock_irq(&tsk
->sighand
->siglock
);
218 timer
= &tsk
->signal
->real_timer
;
220 ovalue
->it_value
= itimer_get_remtime(timer
);
222 = ktime_to_timeval(tsk
->signal
->it_real_incr
);
224 /* We are sharing ->siglock with it_real_fn() */
225 if (hrtimer_try_to_cancel(timer
) < 0) {
226 spin_unlock_irq(&tsk
->sighand
->siglock
);
229 expires
= timeval_to_ktime(value
->it_value
);
230 if (expires
.tv64
!= 0) {
231 tsk
->signal
->it_real_incr
=
232 timeval_to_ktime(value
->it_interval
);
233 hrtimer_start(timer
, expires
, HRTIMER_MODE_REL
);
235 tsk
->signal
->it_real_incr
.tv64
= 0;
237 spin_unlock_irq(&tsk
->sighand
->siglock
);
240 nval
= timeval_to_cputime(&value
->it_value
);
241 ninterval
= timeval_to_cputime(&value
->it_interval
);
242 read_lock(&tasklist_lock
);
243 spin_lock_irq(&tsk
->sighand
->siglock
);
244 cval
= tsk
->signal
->it_virt_expires
;
245 cinterval
= tsk
->signal
->it_virt_incr
;
246 if (!cputime_eq(cval
, cputime_zero
) ||
247 !cputime_eq(nval
, cputime_zero
)) {
248 if (cputime_gt(nval
, cputime_zero
))
249 nval
= cputime_add(nval
,
250 jiffies_to_cputime(1));
251 set_process_cpu_timer(tsk
, CPUCLOCK_VIRT
,
254 tsk
->signal
->it_virt_expires
= nval
;
255 tsk
->signal
->it_virt_incr
= ninterval
;
256 spin_unlock_irq(&tsk
->sighand
->siglock
);
257 read_unlock(&tasklist_lock
);
259 cputime_to_timeval(cval
, &ovalue
->it_value
);
260 cputime_to_timeval(cinterval
, &ovalue
->it_interval
);
264 nval
= timeval_to_cputime(&value
->it_value
);
265 ninterval
= timeval_to_cputime(&value
->it_interval
);
266 read_lock(&tasklist_lock
);
267 spin_lock_irq(&tsk
->sighand
->siglock
);
268 cval
= tsk
->signal
->it_prof_expires
;
269 cinterval
= tsk
->signal
->it_prof_incr
;
270 if (!cputime_eq(cval
, cputime_zero
) ||
271 !cputime_eq(nval
, cputime_zero
)) {
272 if (cputime_gt(nval
, cputime_zero
))
273 nval
= cputime_add(nval
,
274 jiffies_to_cputime(1));
275 set_process_cpu_timer(tsk
, CPUCLOCK_PROF
,
278 tsk
->signal
->it_prof_expires
= nval
;
279 tsk
->signal
->it_prof_incr
= ninterval
;
280 spin_unlock_irq(&tsk
->sighand
->siglock
);
281 read_unlock(&tasklist_lock
);
283 cputime_to_timeval(cval
, &ovalue
->it_value
);
284 cputime_to_timeval(cinterval
, &ovalue
->it_interval
);
294 * alarm_setitimer - set alarm in seconds
296 * @seconds: number of seconds until alarm
297 * 0 disables the alarm
299 * Returns the remaining time in seconds of a pending timer or 0 when
300 * the timer is not active.
302 * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
303 * negative timeval settings which would cause immediate expiry.
305 unsigned int alarm_setitimer(unsigned int seconds
)
307 struct itimerval it_new
, it_old
;
309 #if BITS_PER_LONG < 64
310 if (seconds
> INT_MAX
)
313 it_new
.it_value
.tv_sec
= seconds
;
314 it_new
.it_value
.tv_usec
= 0;
315 it_new
.it_interval
.tv_sec
= it_new
.it_interval
.tv_usec
= 0;
317 do_setitimer(ITIMER_REAL
, &it_new
, &it_old
);
320 * We can't return 0 if we have an alarm pending ... And we'd
321 * better return too much than too little anyway
323 if ((!it_old
.it_value
.tv_sec
&& it_old
.it_value
.tv_usec
) ||
324 it_old
.it_value
.tv_usec
>= 500000)
325 it_old
.it_value
.tv_sec
++;
327 return it_old
.it_value
.tv_sec
;
330 asmlinkage
long sys_setitimer(int which
,
331 struct itimerval __user
*value
,
332 struct itimerval __user
*ovalue
)
334 struct itimerval set_buffer
, get_buffer
;
338 if(copy_from_user(&set_buffer
, value
, sizeof(set_buffer
)))
341 memset((char *) &set_buffer
, 0, sizeof(set_buffer
));
343 error
= do_setitimer(which
, &set_buffer
, ovalue
? &get_buffer
: NULL
);
344 if (error
|| !ovalue
)
347 if (copy_to_user(ovalue
, &get_buffer
, sizeof(get_buffer
)))
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