tracing/kprobes: Fix field creation's bad error handling
[linux-2.6.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 #include <trace/events/timer.h>
16
17 #include <asm/uaccess.h>
18
19 /**
20  * itimer_get_remtime - get remaining time for the timer
21  *
22  * @timer: the timer to read
23  *
24  * Returns the delta between the expiry time and now, which can be
25  * less than zero or 1usec for an pending expired timer
26  */
27 static struct timeval itimer_get_remtime(struct hrtimer *timer)
28 {
29         ktime_t rem = hrtimer_get_remaining(timer);
30
31         /*
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.
35          */
36         if (hrtimer_active(timer)) {
37                 if (rem.tv64 <= 0)
38                         rem.tv64 = NSEC_PER_USEC;
39         } else
40                 rem.tv64 = 0;
41
42         return ktime_to_timeval(rem);
43 }
44
45 static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
46                            struct itimerval *const value)
47 {
48         cputime_t cval, cinterval;
49         struct cpu_itimer *it = &tsk->signal->it[clock_id];
50
51         spin_lock_irq(&tsk->sighand->siglock);
52
53         cval = it->expires;
54         cinterval = it->incr;
55         if (!cputime_eq(cval, cputime_zero)) {
56                 struct task_cputime cputime;
57                 cputime_t t;
58
59                 thread_group_cputimer(tsk, &cputime);
60                 if (clock_id == CPUCLOCK_PROF)
61                         t = cputime_add(cputime.utime, cputime.stime);
62                 else
63                         /* CPUCLOCK_VIRT */
64                         t = cputime.utime;
65
66                 if (cputime_le(cval, t))
67                         /* about to fire */
68                         cval = cputime_one_jiffy;
69                 else
70                         cval = cputime_sub(cval, t);
71         }
72
73         spin_unlock_irq(&tsk->sighand->siglock);
74
75         cputime_to_timeval(cval, &value->it_value);
76         cputime_to_timeval(cinterval, &value->it_interval);
77 }
78
79 int do_getitimer(int which, struct itimerval *value)
80 {
81         struct task_struct *tsk = current;
82
83         switch (which) {
84         case ITIMER_REAL:
85                 spin_lock_irq(&tsk->sighand->siglock);
86                 value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
87                 value->it_interval =
88                         ktime_to_timeval(tsk->signal->it_real_incr);
89                 spin_unlock_irq(&tsk->sighand->siglock);
90                 break;
91         case ITIMER_VIRTUAL:
92                 get_cpu_itimer(tsk, CPUCLOCK_VIRT, value);
93                 break;
94         case ITIMER_PROF:
95                 get_cpu_itimer(tsk, CPUCLOCK_PROF, value);
96                 break;
97         default:
98                 return(-EINVAL);
99         }
100         return 0;
101 }
102
103 SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
104 {
105         int error = -EFAULT;
106         struct itimerval get_buffer;
107
108         if (value) {
109                 error = do_getitimer(which, &get_buffer);
110                 if (!error &&
111                     copy_to_user(value, &get_buffer, sizeof(get_buffer)))
112                         error = -EFAULT;
113         }
114         return error;
115 }
116
117
118 /*
119  * The timer is automagically restarted, when interval != 0
120  */
121 enum hrtimer_restart it_real_fn(struct hrtimer *timer)
122 {
123         struct signal_struct *sig =
124                 container_of(timer, struct signal_struct, real_timer);
125
126         trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0);
127         kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
128
129         return HRTIMER_NORESTART;
130 }
131
132 static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns)
133 {
134         struct timespec ts;
135         s64 cpu_ns;
136
137         cputime_to_timespec(ct, &ts);
138         cpu_ns = timespec_to_ns(&ts);
139
140         return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns;
141 }
142
143 static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
144                            const struct itimerval *const value,
145                            struct itimerval *const ovalue)
146 {
147         cputime_t cval, nval, cinterval, ninterval;
148         s64 ns_ninterval, ns_nval;
149         struct cpu_itimer *it = &tsk->signal->it[clock_id];
150
151         nval = timeval_to_cputime(&value->it_value);
152         ns_nval = timeval_to_ns(&value->it_value);
153         ninterval = timeval_to_cputime(&value->it_interval);
154         ns_ninterval = timeval_to_ns(&value->it_interval);
155
156         it->incr_error = cputime_sub_ns(ninterval, ns_ninterval);
157         it->error = cputime_sub_ns(nval, ns_nval);
158
159         spin_lock_irq(&tsk->sighand->siglock);
160
161         cval = it->expires;
162         cinterval = it->incr;
163         if (!cputime_eq(cval, cputime_zero) ||
164             !cputime_eq(nval, cputime_zero)) {
165                 if (cputime_gt(nval, cputime_zero))
166                         nval = cputime_add(nval, cputime_one_jiffy);
167                 set_process_cpu_timer(tsk, clock_id, &nval, &cval);
168         }
169         it->expires = nval;
170         it->incr = ninterval;
171         trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
172                            ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
173
174         spin_unlock_irq(&tsk->sighand->siglock);
175
176         if (ovalue) {
177                 cputime_to_timeval(cval, &ovalue->it_value);
178                 cputime_to_timeval(cinterval, &ovalue->it_interval);
179         }
180 }
181
182 /*
183  * Returns true if the timeval is in canonical form
184  */
185 #define timeval_valid(t) \
186         (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
187
188 int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
189 {
190         struct task_struct *tsk = current;
191         struct hrtimer *timer;
192         ktime_t expires;
193
194         /*
195          * Validate the timevals in value.
196          */
197         if (!timeval_valid(&value->it_value) ||
198             !timeval_valid(&value->it_interval))
199                 return -EINVAL;
200
201         switch (which) {
202         case ITIMER_REAL:
203 again:
204                 spin_lock_irq(&tsk->sighand->siglock);
205                 timer = &tsk->signal->real_timer;
206                 if (ovalue) {
207                         ovalue->it_value = itimer_get_remtime(timer);
208                         ovalue->it_interval
209                                 = ktime_to_timeval(tsk->signal->it_real_incr);
210                 }
211                 /* We are sharing ->siglock with it_real_fn() */
212                 if (hrtimer_try_to_cancel(timer) < 0) {
213                         spin_unlock_irq(&tsk->sighand->siglock);
214                         goto again;
215                 }
216                 expires = timeval_to_ktime(value->it_value);
217                 if (expires.tv64 != 0) {
218                         tsk->signal->it_real_incr =
219                                 timeval_to_ktime(value->it_interval);
220                         hrtimer_start(timer, expires, HRTIMER_MODE_REL);
221                 } else
222                         tsk->signal->it_real_incr.tv64 = 0;
223
224                 trace_itimer_state(ITIMER_REAL, value, 0);
225                 spin_unlock_irq(&tsk->sighand->siglock);
226                 break;
227         case ITIMER_VIRTUAL:
228                 set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue);
229                 break;
230         case ITIMER_PROF:
231                 set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue);
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 SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
277                 struct itimerval __user *, ovalue)
278 {
279         struct itimerval set_buffer, get_buffer;
280         int error;
281
282         if (value) {
283                 if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
284                         return -EFAULT;
285         } else
286                 memset((char *) &set_buffer, 0, sizeof(set_buffer));
287
288         error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
289         if (error || !ovalue)
290                 return error;
291
292         if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
293                 return -EFAULT;
294         return 0;
295 }