ITIMER_REAL: convert to use struct pid
[linux-3.10.git] / kernel / itimer.c
1 /*
2  * linux/kernel/itimer.c
3  *
4  * Copyright (C) 1992 Darren Senn
5  */
6
7 /* These are all the functions necessary to implement itimers */
8
9 #include <linux/mm.h>
10 #include <linux/interrupt.h>
11 #include <linux/syscalls.h>
12 #include <linux/time.h>
13 #include <linux/posix-timers.h>
14 #include <linux/hrtimer.h>
15
16 #include <asm/uaccess.h>
17
18 /**
19  * itimer_get_remtime - get remaining time for the timer
20  *
21  * @timer: the timer to read
22  *
23  * Returns the delta between the expiry time and now, which can be
24  * less than zero or 1usec for an pending expired timer
25  */
26 static struct timeval itimer_get_remtime(struct hrtimer *timer)
27 {
28         ktime_t rem = hrtimer_get_remaining(timer);
29
30         /*
31          * Racy but safe: if the itimer expires after the above
32          * hrtimer_get_remtime() call but before this condition
33          * then we return 0 - which is correct.
34          */
35         if (hrtimer_active(timer)) {
36                 if (rem.tv64 <= 0)
37                         rem.tv64 = NSEC_PER_USEC;
38         } else
39                 rem.tv64 = 0;
40
41         return ktime_to_timeval(rem);
42 }
43
44 int do_getitimer(int which, struct itimerval *value)
45 {
46         struct task_struct *tsk = current;
47         cputime_t cinterval, cval;
48
49         switch (which) {
50         case ITIMER_REAL:
51                 spin_lock_irq(&tsk->sighand->siglock);
52                 value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
53                 value->it_interval =
54                         ktime_to_timeval(tsk->signal->it_real_incr);
55                 spin_unlock_irq(&tsk->sighand->siglock);
56                 break;
57         case ITIMER_VIRTUAL:
58                 read_lock(&tasklist_lock);
59                 spin_lock_irq(&tsk->sighand->siglock);
60                 cval = tsk->signal->it_virt_expires;
61                 cinterval = tsk->signal->it_virt_incr;
62                 if (!cputime_eq(cval, cputime_zero)) {
63                         struct task_struct *t = tsk;
64                         cputime_t utime = tsk->signal->utime;
65                         do {
66                                 utime = cputime_add(utime, t->utime);
67                                 t = next_thread(t);
68                         } while (t != tsk);
69                         if (cputime_le(cval, utime)) { /* about to fire */
70                                 cval = jiffies_to_cputime(1);
71                         } else {
72                                 cval = cputime_sub(cval, utime);
73                         }
74                 }
75                 spin_unlock_irq(&tsk->sighand->siglock);
76                 read_unlock(&tasklist_lock);
77                 cputime_to_timeval(cval, &value->it_value);
78                 cputime_to_timeval(cinterval, &value->it_interval);
79                 break;
80         case ITIMER_PROF:
81                 read_lock(&tasklist_lock);
82                 spin_lock_irq(&tsk->sighand->siglock);
83                 cval = tsk->signal->it_prof_expires;
84                 cinterval = tsk->signal->it_prof_incr;
85                 if (!cputime_eq(cval, cputime_zero)) {
86                         struct task_struct *t = tsk;
87                         cputime_t ptime = cputime_add(tsk->signal->utime,
88                                                       tsk->signal->stime);
89                         do {
90                                 ptime = cputime_add(ptime,
91                                                     cputime_add(t->utime,
92                                                                 t->stime));
93                                 t = next_thread(t);
94                         } while (t != tsk);
95                         if (cputime_le(cval, ptime)) { /* about to fire */
96                                 cval = jiffies_to_cputime(1);
97                         } else {
98                                 cval = cputime_sub(cval, ptime);
99                         }
100                 }
101                 spin_unlock_irq(&tsk->sighand->siglock);
102                 read_unlock(&tasklist_lock);
103                 cputime_to_timeval(cval, &value->it_value);
104                 cputime_to_timeval(cinterval, &value->it_interval);
105                 break;
106         default:
107                 return(-EINVAL);
108         }
109         return 0;
110 }
111
112 asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
113 {
114         int error = -EFAULT;
115         struct itimerval get_buffer;
116
117         if (value) {
118                 error = do_getitimer(which, &get_buffer);
119                 if (!error &&
120                     copy_to_user(value, &get_buffer, sizeof(get_buffer)))
121                         error = -EFAULT;
122         }
123         return error;
124 }
125
126
127 /*
128  * The timer is automagically restarted, when interval != 0
129  */
130 enum hrtimer_restart it_real_fn(struct hrtimer *timer)
131 {
132         struct signal_struct *sig =
133                 container_of(timer, struct signal_struct, real_timer);
134
135         kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
136
137         return HRTIMER_NORESTART;
138 }
139
140 /*
141  * Returns true if the timeval is in canonical form
142  */
143 #define timeval_valid(t) \
144         (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
145
146 int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
147 {
148         struct task_struct *tsk = current;
149         struct hrtimer *timer;
150         ktime_t expires;
151         cputime_t cval, cinterval, nval, ninterval;
152
153         /*
154          * Validate the timevals in value.
155          */
156         if (!timeval_valid(&value->it_value) ||
157             !timeval_valid(&value->it_interval))
158                 return -EINVAL;
159
160         switch (which) {
161         case ITIMER_REAL:
162 again:
163                 spin_lock_irq(&tsk->sighand->siglock);
164                 timer = &tsk->signal->real_timer;
165                 if (ovalue) {
166                         ovalue->it_value = itimer_get_remtime(timer);
167                         ovalue->it_interval
168                                 = ktime_to_timeval(tsk->signal->it_real_incr);
169                 }
170                 /* We are sharing ->siglock with it_real_fn() */
171                 if (hrtimer_try_to_cancel(timer) < 0) {
172                         spin_unlock_irq(&tsk->sighand->siglock);
173                         goto again;
174                 }
175                 expires = timeval_to_ktime(value->it_value);
176                 if (expires.tv64 != 0) {
177                         tsk->signal->it_real_incr =
178                                 timeval_to_ktime(value->it_interval);
179                         hrtimer_start(timer, expires, HRTIMER_MODE_REL);
180                 } else
181                         tsk->signal->it_real_incr.tv64 = 0;
182
183                 spin_unlock_irq(&tsk->sighand->siglock);
184                 break;
185         case ITIMER_VIRTUAL:
186                 nval = timeval_to_cputime(&value->it_value);
187                 ninterval = timeval_to_cputime(&value->it_interval);
188                 read_lock(&tasklist_lock);
189                 spin_lock_irq(&tsk->sighand->siglock);
190                 cval = tsk->signal->it_virt_expires;
191                 cinterval = tsk->signal->it_virt_incr;
192                 if (!cputime_eq(cval, cputime_zero) ||
193                     !cputime_eq(nval, cputime_zero)) {
194                         if (cputime_gt(nval, cputime_zero))
195                                 nval = cputime_add(nval,
196                                                    jiffies_to_cputime(1));
197                         set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
198                                               &nval, &cval);
199                 }
200                 tsk->signal->it_virt_expires = nval;
201                 tsk->signal->it_virt_incr = ninterval;
202                 spin_unlock_irq(&tsk->sighand->siglock);
203                 read_unlock(&tasklist_lock);
204                 if (ovalue) {
205                         cputime_to_timeval(cval, &ovalue->it_value);
206                         cputime_to_timeval(cinterval, &ovalue->it_interval);
207                 }
208                 break;
209         case ITIMER_PROF:
210                 nval = timeval_to_cputime(&value->it_value);
211                 ninterval = timeval_to_cputime(&value->it_interval);
212                 read_lock(&tasklist_lock);
213                 spin_lock_irq(&tsk->sighand->siglock);
214                 cval = tsk->signal->it_prof_expires;
215                 cinterval = tsk->signal->it_prof_incr;
216                 if (!cputime_eq(cval, cputime_zero) ||
217                     !cputime_eq(nval, cputime_zero)) {
218                         if (cputime_gt(nval, cputime_zero))
219                                 nval = cputime_add(nval,
220                                                    jiffies_to_cputime(1));
221                         set_process_cpu_timer(tsk, CPUCLOCK_PROF,
222                                               &nval, &cval);
223                 }
224                 tsk->signal->it_prof_expires = nval;
225                 tsk->signal->it_prof_incr = ninterval;
226                 spin_unlock_irq(&tsk->sighand->siglock);
227                 read_unlock(&tasklist_lock);
228                 if (ovalue) {
229                         cputime_to_timeval(cval, &ovalue->it_value);
230                         cputime_to_timeval(cinterval, &ovalue->it_interval);
231                 }
232                 break;
233         default:
234                 return -EINVAL;
235         }
236         return 0;
237 }
238
239 /**
240  * alarm_setitimer - set alarm in seconds
241  *
242  * @seconds:    number of seconds until alarm
243  *              0 disables the alarm
244  *
245  * Returns the remaining time in seconds of a pending timer or 0 when
246  * the timer is not active.
247  *
248  * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
249  * negative timeval settings which would cause immediate expiry.
250  */
251 unsigned int alarm_setitimer(unsigned int seconds)
252 {
253         struct itimerval it_new, it_old;
254
255 #if BITS_PER_LONG < 64
256         if (seconds > INT_MAX)
257                 seconds = INT_MAX;
258 #endif
259         it_new.it_value.tv_sec = seconds;
260         it_new.it_value.tv_usec = 0;
261         it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
262
263         do_setitimer(ITIMER_REAL, &it_new, &it_old);
264
265         /*
266          * We can't return 0 if we have an alarm pending ...  And we'd
267          * better return too much than too little anyway
268          */
269         if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
270               it_old.it_value.tv_usec >= 500000)
271                 it_old.it_value.tv_sec++;
272
273         return it_old.it_value.tv_sec;
274 }
275
276 asmlinkage long sys_setitimer(int which,
277                               struct itimerval __user *value,
278                               struct itimerval __user *ovalue)
279 {
280         struct itimerval set_buffer, get_buffer;
281         int error;
282
283         if (value) {
284                 if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
285                         return -EFAULT;
286         } else
287                 memset((char *) &set_buffer, 0, sizeof(set_buffer));
288
289         error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
290         if (error || !ovalue)
291                 return error;
292
293         if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
294                 return -EFAULT;
295         return 0;
296 }