Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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/smp_lock.h> |
| 11 | #include <linux/interrupt.h> |
| 12 | #include <linux/syscalls.h> |
| 13 | #include <linux/time.h> |
| 14 | #include <linux/posix-timers.h> |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 15 | #include <linux/hrtimer.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
| 17 | #include <asm/uaccess.h> |
| 18 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 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) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | { |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 29 | ktime_t rem = hrtimer_get_remaining(timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 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); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | } |
| 44 | |
| 45 | int do_getitimer(int which, struct itimerval *value) |
| 46 | { |
| 47 | struct task_struct *tsk = current; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | cputime_t cinterval, cval; |
| 49 | |
| 50 | switch (which) { |
| 51 | case ITIMER_REAL: |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 52 | spin_lock_irq(&tsk->sighand->siglock); |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 53 | value->it_value = itimer_get_remtime(&tsk->signal->real_timer); |
| 54 | value->it_interval = |
| 55 | ktime_to_timeval(tsk->signal->it_real_incr); |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 56 | spin_unlock_irq(&tsk->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | break; |
| 58 | case ITIMER_VIRTUAL: |
| 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; |
| 66 | do { |
| 67 | utime = cputime_add(utime, t->utime); |
| 68 | t = next_thread(t); |
| 69 | } while (t != tsk); |
| 70 | if (cputime_le(cval, utime)) { /* about to fire */ |
| 71 | cval = jiffies_to_cputime(1); |
| 72 | } else { |
| 73 | cval = cputime_sub(cval, utime); |
| 74 | } |
| 75 | } |
| 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); |
| 80 | break; |
| 81 | case ITIMER_PROF: |
| 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, |
| 89 | tsk->signal->stime); |
| 90 | do { |
| 91 | ptime = cputime_add(ptime, |
| 92 | cputime_add(t->utime, |
| 93 | t->stime)); |
| 94 | t = next_thread(t); |
| 95 | } while (t != tsk); |
| 96 | if (cputime_le(cval, ptime)) { /* about to fire */ |
| 97 | cval = jiffies_to_cputime(1); |
| 98 | } else { |
| 99 | cval = cputime_sub(cval, ptime); |
| 100 | } |
| 101 | } |
| 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); |
| 106 | break; |
| 107 | default: |
| 108 | return(-EINVAL); |
| 109 | } |
| 110 | return 0; |
| 111 | } |
| 112 | |
| 113 | asmlinkage long sys_getitimer(int which, struct itimerval __user *value) |
| 114 | { |
| 115 | int error = -EFAULT; |
| 116 | struct itimerval get_buffer; |
| 117 | |
| 118 | if (value) { |
| 119 | error = do_getitimer(which, &get_buffer); |
| 120 | if (!error && |
| 121 | copy_to_user(value, &get_buffer, sizeof(get_buffer))) |
| 122 | error = -EFAULT; |
| 123 | } |
| 124 | return error; |
| 125 | } |
| 126 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 128 | /* |
| 129 | * The timer is automagically restarted, when interval != 0 |
| 130 | */ |
Thomas Gleixner | c9cb2e3 | 2007-02-16 01:27:49 -0800 | [diff] [blame] | 131 | enum hrtimer_restart it_real_fn(struct hrtimer *timer) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | { |
Roman Zippel | 05cfb61 | 2006-03-26 01:38:12 -0800 | [diff] [blame] | 133 | struct signal_struct *sig = |
| 134 | container_of(timer, struct signal_struct, real_timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | |
Roman Zippel | 05cfb61 | 2006-03-26 01:38:12 -0800 | [diff] [blame] | 136 | send_group_sig_info(SIGALRM, SEND_SIG_PRIV, sig->tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 138 | return HRTIMER_NORESTART; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | } |
| 140 | |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 141 | /* |
| 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 |
| 146 | * |
| 147 | * Print a limited number of warning messages when an invalid timeval |
| 148 | * is detected. |
| 149 | */ |
| 150 | static void fixup_timeval(struct timeval *tv, int interval) |
| 151 | { |
| 152 | static int warnlimit = 10; |
| 153 | unsigned long tmp; |
| 154 | |
| 155 | if (warnlimit > 0) { |
| 156 | warnlimit--; |
| 157 | printk(KERN_WARNING |
| 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); |
| 163 | } |
| 164 | |
| 165 | tmp = 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; |
| 169 | } |
| 170 | |
| 171 | tmp = tv->tv_sec; |
| 172 | if (tmp > LONG_MAX) |
| 173 | tv->tv_sec = LONG_MAX; |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * Returns true if the timeval is in canonical form |
| 178 | */ |
| 179 | #define timeval_valid(t) \ |
| 180 | (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC)) |
| 181 | |
| 182 | /* |
| 183 | * Check for invalid timevals, sanitize them and print a limited |
| 184 | * number of warnings. |
| 185 | */ |
| 186 | static void check_itimerval(struct itimerval *value) { |
| 187 | |
| 188 | if (unlikely(!timeval_valid(&value->it_value))) |
| 189 | fixup_timeval(&value->it_value, 0); |
| 190 | |
| 191 | if (unlikely(!timeval_valid(&value->it_interval))) |
| 192 | fixup_timeval(&value->it_interval, 1); |
| 193 | } |
| 194 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) |
| 196 | { |
| 197 | struct task_struct *tsk = current; |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 198 | struct hrtimer *timer; |
| 199 | ktime_t expires; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | cputime_t cval, cinterval, nval, ninterval; |
| 201 | |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 202 | /* |
| 203 | * Validate the timevals in value. |
| 204 | * |
| 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. |
| 209 | * |
| 210 | * Scheduled for replacement in March 2007 |
| 211 | */ |
| 212 | check_itimerval(value); |
| 213 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | switch (which) { |
| 215 | case ITIMER_REAL: |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 216 | again: |
| 217 | spin_lock_irq(&tsk->sighand->siglock); |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 218 | timer = &tsk->signal->real_timer; |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 219 | if (ovalue) { |
| 220 | ovalue->it_value = itimer_get_remtime(timer); |
| 221 | ovalue->it_interval |
| 222 | = ktime_to_timeval(tsk->signal->it_real_incr); |
Oleg Nesterov | f01b1b0 | 2005-06-28 20:44:47 -0700 | [diff] [blame] | 223 | } |
Thomas Gleixner | a16a1c0 | 2006-02-01 03:05:09 -0800 | [diff] [blame] | 224 | /* We are sharing ->siglock with it_real_fn() */ |
| 225 | if (hrtimer_try_to_cancel(timer) < 0) { |
| 226 | spin_unlock_irq(&tsk->sighand->siglock); |
| 227 | goto again; |
| 228 | } |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 229 | expires = timeval_to_ktime(value->it_value); |
Thomas Gleixner | 8bfd9a7 | 2007-02-16 01:28:12 -0800 | [diff] [blame] | 230 | if (expires.tv64 != 0) { |
| 231 | tsk->signal->it_real_incr = |
| 232 | timeval_to_ktime(value->it_interval); |
Thomas Gleixner | c9cb2e3 | 2007-02-16 01:27:49 -0800 | [diff] [blame] | 233 | hrtimer_start(timer, expires, HRTIMER_MODE_REL); |
Thomas Gleixner | 8bfd9a7 | 2007-02-16 01:28:12 -0800 | [diff] [blame] | 234 | } else |
| 235 | tsk->signal->it_real_incr.tv64 = 0; |
| 236 | |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 237 | spin_unlock_irq(&tsk->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | break; |
| 239 | case ITIMER_VIRTUAL: |
| 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, |
| 252 | &nval, &cval); |
| 253 | } |
| 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); |
| 258 | if (ovalue) { |
| 259 | cputime_to_timeval(cval, &ovalue->it_value); |
| 260 | cputime_to_timeval(cinterval, &ovalue->it_interval); |
| 261 | } |
| 262 | break; |
| 263 | case ITIMER_PROF: |
| 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, |
| 276 | &nval, &cval); |
| 277 | } |
| 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); |
| 282 | if (ovalue) { |
| 283 | cputime_to_timeval(cval, &ovalue->it_value); |
| 284 | cputime_to_timeval(cinterval, &ovalue->it_interval); |
| 285 | } |
| 286 | break; |
| 287 | default: |
| 288 | return -EINVAL; |
| 289 | } |
| 290 | return 0; |
| 291 | } |
| 292 | |
Thomas Gleixner | c08b8a4 | 2006-03-25 03:06:33 -0800 | [diff] [blame] | 293 | /** |
| 294 | * alarm_setitimer - set alarm in seconds |
| 295 | * |
| 296 | * @seconds: number of seconds until alarm |
| 297 | * 0 disables the alarm |
| 298 | * |
| 299 | * Returns the remaining time in seconds of a pending timer or 0 when |
| 300 | * the timer is not active. |
| 301 | * |
| 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. |
| 304 | */ |
| 305 | unsigned int alarm_setitimer(unsigned int seconds) |
| 306 | { |
| 307 | struct itimerval it_new, it_old; |
| 308 | |
| 309 | #if BITS_PER_LONG < 64 |
| 310 | if (seconds > INT_MAX) |
| 311 | seconds = INT_MAX; |
| 312 | #endif |
| 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; |
| 316 | |
| 317 | do_setitimer(ITIMER_REAL, &it_new, &it_old); |
| 318 | |
| 319 | /* |
| 320 | * We can't return 0 if we have an alarm pending ... And we'd |
| 321 | * better return too much than too little anyway |
| 322 | */ |
| 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++; |
| 326 | |
| 327 | return it_old.it_value.tv_sec; |
| 328 | } |
| 329 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 330 | asmlinkage long sys_setitimer(int which, |
| 331 | struct itimerval __user *value, |
| 332 | struct itimerval __user *ovalue) |
| 333 | { |
| 334 | struct itimerval set_buffer, get_buffer; |
| 335 | int error; |
| 336 | |
| 337 | if (value) { |
| 338 | if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) |
| 339 | return -EFAULT; |
| 340 | } else |
| 341 | memset((char *) &set_buffer, 0, sizeof(set_buffer)); |
| 342 | |
| 343 | error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); |
| 344 | if (error || !ovalue) |
| 345 | return error; |
| 346 | |
| 347 | if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) |
| 348 | return -EFAULT; |
| 349 | return 0; |
| 350 | } |