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Davide Libenzib215e282007-05-10 22:23:16 -07001/*
2 * fs/timerfd.c
3 *
4 * Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
5 *
6 *
7 * Thanks to Thomas Gleixner for code reviews and useful comments.
8 *
9 */
10
Todd Poynor11ffa9d2013-05-15 14:38:12 -070011#include <linux/alarmtimer.h>
Davide Libenzib215e282007-05-10 22:23:16 -070012#include <linux/file.h>
13#include <linux/poll.h>
14#include <linux/init.h>
15#include <linux/fs.h>
16#include <linux/sched.h>
17#include <linux/kernel.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090018#include <linux/slab.h>
Davide Libenzib215e282007-05-10 22:23:16 -070019#include <linux/list.h>
20#include <linux/spinlock.h>
21#include <linux/time.h>
22#include <linux/hrtimer.h>
23#include <linux/anon_inodes.h>
24#include <linux/timerfd.h>
Adrian Bunk45cc2b92008-04-29 00:58:59 -070025#include <linux/syscalls.h>
Al Viro9d94b9e2012-12-27 16:52:33 -050026#include <linux/compat.h>
Thomas Gleixner9ec26902011-05-20 16:18:50 +020027#include <linux/rcupdate.h>
Davide Libenzib215e282007-05-10 22:23:16 -070028
29struct timerfd_ctx {
Todd Poynor11ffa9d2013-05-15 14:38:12 -070030 union {
31 struct hrtimer tmr;
32 struct alarm alarm;
33 } t;
Davide Libenzib215e282007-05-10 22:23:16 -070034 ktime_t tintv;
Thomas Gleixner99ee5312011-04-27 14:16:42 +020035 ktime_t moffs;
Davide Libenzib215e282007-05-10 22:23:16 -070036 wait_queue_head_t wqh;
Davide Libenzi4d672e72008-02-04 22:27:26 -080037 u64 ticks;
Davide Libenzi4d672e72008-02-04 22:27:26 -080038 int clockid;
Cyrill Gorcunovaf9c4952014-07-16 01:54:52 +040039 short unsigned expired;
40 short unsigned settime_flags; /* to show in fdinfo */
Thomas Gleixner9ec26902011-05-20 16:18:50 +020041 struct rcu_head rcu;
42 struct list_head clist;
Thomas Gleixner99ee5312011-04-27 14:16:42 +020043 bool might_cancel;
Davide Libenzib215e282007-05-10 22:23:16 -070044};
45
Thomas Gleixner9ec26902011-05-20 16:18:50 +020046static LIST_HEAD(cancel_list);
47static DEFINE_SPINLOCK(cancel_lock);
48
Todd Poynor11ffa9d2013-05-15 14:38:12 -070049static inline bool isalarm(struct timerfd_ctx *ctx)
50{
51 return ctx->clockid == CLOCK_REALTIME_ALARM ||
52 ctx->clockid == CLOCK_BOOTTIME_ALARM;
53}
54
Davide Libenzib215e282007-05-10 22:23:16 -070055/*
56 * This gets called when the timer event triggers. We set the "expired"
57 * flag, but we do not re-arm the timer (in case it's necessary,
Thomas Gleixner2456e852016-12-25 11:38:40 +010058 * tintv != 0) until the timer is accessed.
Davide Libenzib215e282007-05-10 22:23:16 -070059 */
Todd Poynor11ffa9d2013-05-15 14:38:12 -070060static void timerfd_triggered(struct timerfd_ctx *ctx)
Davide Libenzib215e282007-05-10 22:23:16 -070061{
Davide Libenzib215e282007-05-10 22:23:16 -070062 unsigned long flags;
63
Davide Libenzi18963c02007-05-18 12:02:33 -070064 spin_lock_irqsave(&ctx->wqh.lock, flags);
Davide Libenzib215e282007-05-10 22:23:16 -070065 ctx->expired = 1;
Davide Libenzi4d672e72008-02-04 22:27:26 -080066 ctx->ticks++;
Davide Libenzib215e282007-05-10 22:23:16 -070067 wake_up_locked(&ctx->wqh);
Davide Libenzi18963c02007-05-18 12:02:33 -070068 spin_unlock_irqrestore(&ctx->wqh.lock, flags);
Todd Poynor11ffa9d2013-05-15 14:38:12 -070069}
Davide Libenzib215e282007-05-10 22:23:16 -070070
Todd Poynor11ffa9d2013-05-15 14:38:12 -070071static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
72{
73 struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx,
74 t.tmr);
75 timerfd_triggered(ctx);
Davide Libenzib215e282007-05-10 22:23:16 -070076 return HRTIMER_NORESTART;
77}
78
Todd Poynor11ffa9d2013-05-15 14:38:12 -070079static enum alarmtimer_restart timerfd_alarmproc(struct alarm *alarm,
80 ktime_t now)
81{
82 struct timerfd_ctx *ctx = container_of(alarm, struct timerfd_ctx,
83 t.alarm);
84 timerfd_triggered(ctx);
85 return ALARMTIMER_NORESTART;
86}
87
Thomas Gleixner9ec26902011-05-20 16:18:50 +020088/*
89 * Called when the clock was set to cancel the timers in the cancel
Max Asbock1123d9392011-06-13 10:18:32 -070090 * list. This will wake up processes waiting on these timers. The
91 * wake-up requires ctx->ticks to be non zero, therefore we increment
92 * it before calling wake_up_locked().
Thomas Gleixner9ec26902011-05-20 16:18:50 +020093 */
94void timerfd_clock_was_set(void)
95{
Thomas Gleixner2456e852016-12-25 11:38:40 +010096 ktime_t moffs = ktime_mono_to_real(0);
Thomas Gleixner9ec26902011-05-20 16:18:50 +020097 struct timerfd_ctx *ctx;
98 unsigned long flags;
99
100 rcu_read_lock();
101 list_for_each_entry_rcu(ctx, &cancel_list, clist) {
102 if (!ctx->might_cancel)
103 continue;
104 spin_lock_irqsave(&ctx->wqh.lock, flags);
Thomas Gleixner2456e852016-12-25 11:38:40 +0100105 if (ctx->moffs != moffs) {
106 ctx->moffs = KTIME_MAX;
Max Asbock1123d9392011-06-13 10:18:32 -0700107 ctx->ticks++;
Thomas Gleixner9ec26902011-05-20 16:18:50 +0200108 wake_up_locked(&ctx->wqh);
109 }
110 spin_unlock_irqrestore(&ctx->wqh.lock, flags);
111 }
112 rcu_read_unlock();
113}
114
115static void timerfd_remove_cancel(struct timerfd_ctx *ctx)
116{
117 if (ctx->might_cancel) {
118 ctx->might_cancel = false;
119 spin_lock(&cancel_lock);
120 list_del_rcu(&ctx->clist);
121 spin_unlock(&cancel_lock);
122 }
123}
124
125static bool timerfd_canceled(struct timerfd_ctx *ctx)
126{
Thomas Gleixner2456e852016-12-25 11:38:40 +0100127 if (!ctx->might_cancel || ctx->moffs != KTIME_MAX)
Thomas Gleixner9ec26902011-05-20 16:18:50 +0200128 return false;
Thomas Gleixner2456e852016-12-25 11:38:40 +0100129 ctx->moffs = ktime_mono_to_real(0);
Thomas Gleixner9ec26902011-05-20 16:18:50 +0200130 return true;
131}
132
133static void timerfd_setup_cancel(struct timerfd_ctx *ctx, int flags)
134{
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700135 if ((ctx->clockid == CLOCK_REALTIME ||
136 ctx->clockid == CLOCK_REALTIME_ALARM) &&
137 (flags & TFD_TIMER_ABSTIME) && (flags & TFD_TIMER_CANCEL_ON_SET)) {
Thomas Gleixner9ec26902011-05-20 16:18:50 +0200138 if (!ctx->might_cancel) {
139 ctx->might_cancel = true;
140 spin_lock(&cancel_lock);
141 list_add_rcu(&ctx->clist, &cancel_list);
142 spin_unlock(&cancel_lock);
143 }
144 } else if (ctx->might_cancel) {
145 timerfd_remove_cancel(ctx);
146 }
147}
148
Davide Libenzi4d672e72008-02-04 22:27:26 -0800149static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
150{
Arjan van de Ven76369472008-09-01 15:00:14 -0700151 ktime_t remaining;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800152
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700153 if (isalarm(ctx))
154 remaining = alarm_expires_remaining(&ctx->t.alarm);
155 else
Thomas Gleixnerb62526e2016-01-14 16:54:46 +0000156 remaining = hrtimer_expires_remaining_adjusted(&ctx->t.tmr);
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700157
Thomas Gleixner8b0e1952016-12-25 12:30:41 +0100158 return remaining < 0 ? 0: remaining;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800159}
160
Thomas Gleixner99ee5312011-04-27 14:16:42 +0200161static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
162 const struct itimerspec *ktmr)
Davide Libenzib215e282007-05-10 22:23:16 -0700163{
164 enum hrtimer_mode htmode;
165 ktime_t texp;
Thomas Gleixner99ee5312011-04-27 14:16:42 +0200166 int clockid = ctx->clockid;
Davide Libenzib215e282007-05-10 22:23:16 -0700167
168 htmode = (flags & TFD_TIMER_ABSTIME) ?
169 HRTIMER_MODE_ABS: HRTIMER_MODE_REL;
170
171 texp = timespec_to_ktime(ktmr->it_value);
172 ctx->expired = 0;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800173 ctx->ticks = 0;
Davide Libenzib215e282007-05-10 22:23:16 -0700174 ctx->tintv = timespec_to_ktime(ktmr->it_interval);
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700175
176 if (isalarm(ctx)) {
177 alarm_init(&ctx->t.alarm,
178 ctx->clockid == CLOCK_REALTIME_ALARM ?
179 ALARM_REALTIME : ALARM_BOOTTIME,
180 timerfd_alarmproc);
181 } else {
182 hrtimer_init(&ctx->t.tmr, clockid, htmode);
183 hrtimer_set_expires(&ctx->t.tmr, texp);
184 ctx->t.tmr.function = timerfd_tmrproc;
185 }
186
Thomas Gleixner2456e852016-12-25 11:38:40 +0100187 if (texp != 0) {
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700188 if (isalarm(ctx)) {
189 if (flags & TFD_TIMER_ABSTIME)
190 alarm_start(&ctx->t.alarm, texp);
191 else
192 alarm_start_relative(&ctx->t.alarm, texp);
193 } else {
194 hrtimer_start(&ctx->t.tmr, texp, htmode);
195 }
196
Thomas Gleixner99ee5312011-04-27 14:16:42 +0200197 if (timerfd_canceled(ctx))
198 return -ECANCELED;
199 }
Cyrill Gorcunovaf9c4952014-07-16 01:54:52 +0400200
201 ctx->settime_flags = flags & TFD_SETTIME_FLAGS;
Thomas Gleixner99ee5312011-04-27 14:16:42 +0200202 return 0;
Davide Libenzib215e282007-05-10 22:23:16 -0700203}
204
205static int timerfd_release(struct inode *inode, struct file *file)
206{
207 struct timerfd_ctx *ctx = file->private_data;
208
Thomas Gleixner9ec26902011-05-20 16:18:50 +0200209 timerfd_remove_cancel(ctx);
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700210
211 if (isalarm(ctx))
212 alarm_cancel(&ctx->t.alarm);
213 else
214 hrtimer_cancel(&ctx->t.tmr);
Thomas Gleixner9ec26902011-05-20 16:18:50 +0200215 kfree_rcu(ctx, rcu);
Davide Libenzib215e282007-05-10 22:23:16 -0700216 return 0;
217}
218
219static unsigned int timerfd_poll(struct file *file, poll_table *wait)
220{
221 struct timerfd_ctx *ctx = file->private_data;
222 unsigned int events = 0;
223 unsigned long flags;
224
225 poll_wait(file, &ctx->wqh, wait);
226
Davide Libenzi18963c02007-05-18 12:02:33 -0700227 spin_lock_irqsave(&ctx->wqh.lock, flags);
Davide Libenzi4d672e72008-02-04 22:27:26 -0800228 if (ctx->ticks)
Davide Libenzib215e282007-05-10 22:23:16 -0700229 events |= POLLIN;
Davide Libenzi18963c02007-05-18 12:02:33 -0700230 spin_unlock_irqrestore(&ctx->wqh.lock, flags);
Davide Libenzib215e282007-05-10 22:23:16 -0700231
232 return events;
233}
234
235static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
236 loff_t *ppos)
237{
238 struct timerfd_ctx *ctx = file->private_data;
239 ssize_t res;
Davide Libenzi09828402007-07-26 10:41:07 -0700240 u64 ticks = 0;
Davide Libenzib215e282007-05-10 22:23:16 -0700241
242 if (count < sizeof(ticks))
243 return -EINVAL;
Davide Libenzi18963c02007-05-18 12:02:33 -0700244 spin_lock_irq(&ctx->wqh.lock);
Michal Nazarewicz8120a8a2010-05-05 12:53:12 +0200245 if (file->f_flags & O_NONBLOCK)
246 res = -EAGAIN;
247 else
248 res = wait_event_interruptible_locked_irq(ctx->wqh, ctx->ticks);
Thomas Gleixner99ee5312011-04-27 14:16:42 +0200249
Thomas Gleixner9ec26902011-05-20 16:18:50 +0200250 /*
251 * If clock has changed, we do not care about the
252 * ticks and we do not rearm the timer. Userspace must
253 * reevaluate anyway.
254 */
255 if (timerfd_canceled(ctx)) {
256 ctx->ticks = 0;
257 ctx->expired = 0;
258 res = -ECANCELED;
259 }
260
Davide Libenzi4d672e72008-02-04 22:27:26 -0800261 if (ctx->ticks) {
262 ticks = ctx->ticks;
Thomas Gleixner99ee5312011-04-27 14:16:42 +0200263
Thomas Gleixner2456e852016-12-25 11:38:40 +0100264 if (ctx->expired && ctx->tintv) {
Davide Libenzib215e282007-05-10 22:23:16 -0700265 /*
Thomas Gleixner2456e852016-12-25 11:38:40 +0100266 * If tintv != 0, this is a periodic timer that
Davide Libenzib215e282007-05-10 22:23:16 -0700267 * needs to be re-armed. We avoid doing it in the timer
268 * callback to avoid DoS attacks specifying a very
269 * short timer period.
270 */
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700271 if (isalarm(ctx)) {
272 ticks += alarm_forward_now(
273 &ctx->t.alarm, ctx->tintv) - 1;
274 alarm_restart(&ctx->t.alarm);
275 } else {
276 ticks += hrtimer_forward_now(&ctx->t.tmr,
277 ctx->tintv) - 1;
278 hrtimer_restart(&ctx->t.tmr);
279 }
Davide Libenzi4d672e72008-02-04 22:27:26 -0800280 }
281 ctx->expired = 0;
282 ctx->ticks = 0;
Davide Libenzib215e282007-05-10 22:23:16 -0700283 }
Davide Libenzi18963c02007-05-18 12:02:33 -0700284 spin_unlock_irq(&ctx->wqh.lock);
Davide Libenzib215e282007-05-10 22:23:16 -0700285 if (ticks)
Davide Libenzi09828402007-07-26 10:41:07 -0700286 res = put_user(ticks, (u64 __user *) buf) ? -EFAULT: sizeof(ticks);
Davide Libenzib215e282007-05-10 22:23:16 -0700287 return res;
288}
289
Cyrill Gorcunovaf9c4952014-07-16 01:54:52 +0400290#ifdef CONFIG_PROC_FS
Joe Perchesa3816ab2014-09-29 16:08:25 -0700291static void timerfd_show(struct seq_file *m, struct file *file)
Cyrill Gorcunovaf9c4952014-07-16 01:54:52 +0400292{
293 struct timerfd_ctx *ctx = file->private_data;
294 struct itimerspec t;
295
296 spin_lock_irq(&ctx->wqh.lock);
297 t.it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
298 t.it_interval = ktime_to_timespec(ctx->tintv);
299 spin_unlock_irq(&ctx->wqh.lock);
300
Joe Perchesa3816ab2014-09-29 16:08:25 -0700301 seq_printf(m,
302 "clockid: %d\n"
303 "ticks: %llu\n"
304 "settime flags: 0%o\n"
305 "it_value: (%llu, %llu)\n"
306 "it_interval: (%llu, %llu)\n",
307 ctx->clockid,
308 (unsigned long long)ctx->ticks,
309 ctx->settime_flags,
310 (unsigned long long)t.it_value.tv_sec,
311 (unsigned long long)t.it_value.tv_nsec,
312 (unsigned long long)t.it_interval.tv_sec,
313 (unsigned long long)t.it_interval.tv_nsec);
Cyrill Gorcunovaf9c4952014-07-16 01:54:52 +0400314}
315#else
316#define timerfd_show NULL
317#endif
318
Cyrill Gorcunov5442e9f2014-07-16 01:54:54 +0400319#ifdef CONFIG_CHECKPOINT_RESTORE
320static long timerfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
321{
322 struct timerfd_ctx *ctx = file->private_data;
323 int ret = 0;
324
325 switch (cmd) {
326 case TFD_IOC_SET_TICKS: {
327 u64 ticks;
328
329 if (copy_from_user(&ticks, (u64 __user *)arg, sizeof(ticks)))
330 return -EFAULT;
331 if (!ticks)
332 return -EINVAL;
333
334 spin_lock_irq(&ctx->wqh.lock);
335 if (!timerfd_canceled(ctx)) {
336 ctx->ticks = ticks;
Dan Carpenter88299c92014-08-01 11:28:48 +0300337 wake_up_locked(&ctx->wqh);
Cyrill Gorcunov5442e9f2014-07-16 01:54:54 +0400338 } else
339 ret = -ECANCELED;
340 spin_unlock_irq(&ctx->wqh.lock);
341 break;
342 }
343 default:
344 ret = -ENOTTY;
345 break;
346 }
347
348 return ret;
349}
350#else
351#define timerfd_ioctl NULL
352#endif
353
Davide Libenzib215e282007-05-10 22:23:16 -0700354static const struct file_operations timerfd_fops = {
355 .release = timerfd_release,
356 .poll = timerfd_poll,
357 .read = timerfd_read,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200358 .llseek = noop_llseek,
Cyrill Gorcunovaf9c4952014-07-16 01:54:52 +0400359 .show_fdinfo = timerfd_show,
Cyrill Gorcunov5442e9f2014-07-16 01:54:54 +0400360 .unlocked_ioctl = timerfd_ioctl,
Davide Libenzib215e282007-05-10 22:23:16 -0700361};
362
Al Viro2903ff02012-08-28 12:52:22 -0400363static int timerfd_fget(int fd, struct fd *p)
Davide Libenzib215e282007-05-10 22:23:16 -0700364{
Al Viro2903ff02012-08-28 12:52:22 -0400365 struct fd f = fdget(fd);
366 if (!f.file)
367 return -EBADF;
368 if (f.file->f_op != &timerfd_fops) {
369 fdput(f);
370 return -EINVAL;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800371 }
Al Viro2903ff02012-08-28 12:52:22 -0400372 *p = f;
373 return 0;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800374}
375
Heiko Carstens836f92a2009-01-14 14:14:33 +0100376SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
Davide Libenzi4d672e72008-02-04 22:27:26 -0800377{
Al Viro2030a422008-02-23 06:46:49 -0500378 int ufd;
Davide Libenzib215e282007-05-10 22:23:16 -0700379 struct timerfd_ctx *ctx;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800380
Ulrich Dreppere38b36f2008-07-23 21:29:42 -0700381 /* Check the TFD_* constants for consistency. */
382 BUILD_BUG_ON(TFD_CLOEXEC != O_CLOEXEC);
383 BUILD_BUG_ON(TFD_NONBLOCK != O_NONBLOCK);
384
Davide Libenzi610d18f2009-02-18 14:48:18 -0800385 if ((flags & ~TFD_CREATE_FLAGS) ||
386 (clockid != CLOCK_MONOTONIC &&
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700387 clockid != CLOCK_REALTIME &&
388 clockid != CLOCK_REALTIME_ALARM &&
Greg Hackmann4a2378a2014-01-08 10:57:03 -0800389 clockid != CLOCK_BOOTTIME &&
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700390 clockid != CLOCK_BOOTTIME_ALARM))
Davide Libenzi4d672e72008-02-04 22:27:26 -0800391 return -EINVAL;
392
Eric Caruso2895a5e2016-06-08 16:08:59 -0700393 if (!capable(CAP_WAKE_ALARM) &&
394 (clockid == CLOCK_REALTIME_ALARM ||
395 clockid == CLOCK_BOOTTIME_ALARM))
396 return -EPERM;
397
Davide Libenzi4d672e72008-02-04 22:27:26 -0800398 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
399 if (!ctx)
400 return -ENOMEM;
401
402 init_waitqueue_head(&ctx->wqh);
403 ctx->clockid = clockid;
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700404
405 if (isalarm(ctx))
406 alarm_init(&ctx->t.alarm,
407 ctx->clockid == CLOCK_REALTIME_ALARM ?
408 ALARM_REALTIME : ALARM_BOOTTIME,
409 timerfd_alarmproc);
410 else
411 hrtimer_init(&ctx->t.tmr, clockid, HRTIMER_MODE_ABS);
412
Thomas Gleixner2456e852016-12-25 11:38:40 +0100413 ctx->moffs = ktime_mono_to_real(0);
Davide Libenzi4d672e72008-02-04 22:27:26 -0800414
Ulrich Drepper11fcb6c2008-07-23 21:29:26 -0700415 ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,
Roland Dreier628ff7c2009-12-18 09:41:24 -0800416 O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));
Al Viro2030a422008-02-23 06:46:49 -0500417 if (ufd < 0)
Davide Libenzi4d672e72008-02-04 22:27:26 -0800418 kfree(ctx);
Davide Libenzi4d672e72008-02-04 22:27:26 -0800419
420 return ufd;
421}
422
Al Viro9d94b9e2012-12-27 16:52:33 -0500423static int do_timerfd_settime(int ufd, int flags,
424 const struct itimerspec *new,
425 struct itimerspec *old)
Davide Libenzi4d672e72008-02-04 22:27:26 -0800426{
Al Viro2903ff02012-08-28 12:52:22 -0400427 struct fd f;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800428 struct timerfd_ctx *ctx;
Al Viro2903ff02012-08-28 12:52:22 -0400429 int ret;
Davide Libenzib215e282007-05-10 22:23:16 -0700430
Davide Libenzi610d18f2009-02-18 14:48:18 -0800431 if ((flags & ~TFD_SETTIME_FLAGS) ||
Al Viro9d94b9e2012-12-27 16:52:33 -0500432 !timespec_valid(&new->it_value) ||
433 !timespec_valid(&new->it_interval))
Davide Libenzib215e282007-05-10 22:23:16 -0700434 return -EINVAL;
435
Al Viro2903ff02012-08-28 12:52:22 -0400436 ret = timerfd_fget(ufd, &f);
437 if (ret)
438 return ret;
439 ctx = f.file->private_data;
Davide Libenzib215e282007-05-10 22:23:16 -0700440
Eric Caruso2895a5e2016-06-08 16:08:59 -0700441 if (!capable(CAP_WAKE_ALARM) && isalarm(ctx)) {
442 fdput(f);
443 return -EPERM;
444 }
445
Thomas Gleixner9ec26902011-05-20 16:18:50 +0200446 timerfd_setup_cancel(ctx, flags);
447
Davide Libenzi4d672e72008-02-04 22:27:26 -0800448 /*
449 * We need to stop the existing timer before reprogramming
450 * it to the new values.
451 */
452 for (;;) {
453 spin_lock_irq(&ctx->wqh.lock);
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700454
455 if (isalarm(ctx)) {
456 if (alarm_try_to_cancel(&ctx->t.alarm) >= 0)
457 break;
458 } else {
459 if (hrtimer_try_to_cancel(&ctx->t.tmr) >= 0)
460 break;
461 }
Davide Libenzi18963c02007-05-18 12:02:33 -0700462 spin_unlock_irq(&ctx->wqh.lock);
Davide Libenzi4d672e72008-02-04 22:27:26 -0800463 cpu_relax();
Davide Libenzib215e282007-05-10 22:23:16 -0700464 }
465
Davide Libenzi4d672e72008-02-04 22:27:26 -0800466 /*
467 * If the timer is expired and it's periodic, we need to advance it
468 * because the caller may want to know the previous expiration time.
469 * We do not update "ticks" and "expired" since the timer will be
470 * re-programmed again in the following timerfd_setup() call.
471 */
Thomas Gleixner2456e852016-12-25 11:38:40 +0100472 if (ctx->expired && ctx->tintv) {
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700473 if (isalarm(ctx))
474 alarm_forward_now(&ctx->t.alarm, ctx->tintv);
475 else
476 hrtimer_forward_now(&ctx->t.tmr, ctx->tintv);
477 }
Davide Libenzib215e282007-05-10 22:23:16 -0700478
Al Viro9d94b9e2012-12-27 16:52:33 -0500479 old->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
480 old->it_interval = ktime_to_timespec(ctx->tintv);
Davide Libenzi4d672e72008-02-04 22:27:26 -0800481
482 /*
483 * Re-program the timer to the new value ...
484 */
Al Viro9d94b9e2012-12-27 16:52:33 -0500485 ret = timerfd_setup(ctx, flags, new);
Davide Libenzi4d672e72008-02-04 22:27:26 -0800486
487 spin_unlock_irq(&ctx->wqh.lock);
Al Viro2903ff02012-08-28 12:52:22 -0400488 fdput(f);
Thomas Gleixner99ee5312011-04-27 14:16:42 +0200489 return ret;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800490}
491
Al Viro9d94b9e2012-12-27 16:52:33 -0500492static int do_timerfd_gettime(int ufd, struct itimerspec *t)
Davide Libenzi4d672e72008-02-04 22:27:26 -0800493{
Al Viro2903ff02012-08-28 12:52:22 -0400494 struct fd f;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800495 struct timerfd_ctx *ctx;
Al Viro2903ff02012-08-28 12:52:22 -0400496 int ret = timerfd_fget(ufd, &f);
497 if (ret)
498 return ret;
499 ctx = f.file->private_data;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800500
501 spin_lock_irq(&ctx->wqh.lock);
Thomas Gleixner2456e852016-12-25 11:38:40 +0100502 if (ctx->expired && ctx->tintv) {
Davide Libenzi4d672e72008-02-04 22:27:26 -0800503 ctx->expired = 0;
Todd Poynor11ffa9d2013-05-15 14:38:12 -0700504
505 if (isalarm(ctx)) {
506 ctx->ticks +=
507 alarm_forward_now(
508 &ctx->t.alarm, ctx->tintv) - 1;
509 alarm_restart(&ctx->t.alarm);
510 } else {
511 ctx->ticks +=
512 hrtimer_forward_now(&ctx->t.tmr, ctx->tintv)
513 - 1;
514 hrtimer_restart(&ctx->t.tmr);
515 }
Davide Libenzi4d672e72008-02-04 22:27:26 -0800516 }
Al Viro9d94b9e2012-12-27 16:52:33 -0500517 t->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
518 t->it_interval = ktime_to_timespec(ctx->tintv);
Davide Libenzi4d672e72008-02-04 22:27:26 -0800519 spin_unlock_irq(&ctx->wqh.lock);
Al Viro2903ff02012-08-28 12:52:22 -0400520 fdput(f);
Al Viro9d94b9e2012-12-27 16:52:33 -0500521 return 0;
522}
Davide Libenzi4d672e72008-02-04 22:27:26 -0800523
Al Viro9d94b9e2012-12-27 16:52:33 -0500524SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags,
525 const struct itimerspec __user *, utmr,
526 struct itimerspec __user *, otmr)
527{
528 struct itimerspec new, old;
529 int ret;
530
531 if (copy_from_user(&new, utmr, sizeof(new)))
532 return -EFAULT;
533 ret = do_timerfd_settime(ufd, flags, &new, &old);
534 if (ret)
535 return ret;
536 if (otmr && copy_to_user(otmr, &old, sizeof(old)))
537 return -EFAULT;
538
539 return ret;
540}
541
542SYSCALL_DEFINE2(timerfd_gettime, int, ufd, struct itimerspec __user *, otmr)
543{
544 struct itimerspec kotmr;
545 int ret = do_timerfd_gettime(ufd, &kotmr);
546 if (ret)
547 return ret;
Davide Libenzi4d672e72008-02-04 22:27:26 -0800548 return copy_to_user(otmr, &kotmr, sizeof(kotmr)) ? -EFAULT: 0;
Davide Libenzib215e282007-05-10 22:23:16 -0700549}
550
Heiko Carstens0e803ba2013-03-02 12:26:30 +0100551#ifdef CONFIG_COMPAT
Al Viro9d94b9e2012-12-27 16:52:33 -0500552COMPAT_SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags,
Heiko Carstens0e803ba2013-03-02 12:26:30 +0100553 const struct compat_itimerspec __user *, utmr,
554 struct compat_itimerspec __user *, otmr)
Al Viro9d94b9e2012-12-27 16:52:33 -0500555{
556 struct itimerspec new, old;
557 int ret;
558
559 if (get_compat_itimerspec(&new, utmr))
560 return -EFAULT;
561 ret = do_timerfd_settime(ufd, flags, &new, &old);
562 if (ret)
563 return ret;
564 if (otmr && put_compat_itimerspec(otmr, &old))
565 return -EFAULT;
566 return ret;
567}
568
569COMPAT_SYSCALL_DEFINE2(timerfd_gettime, int, ufd,
Heiko Carstens0e803ba2013-03-02 12:26:30 +0100570 struct compat_itimerspec __user *, otmr)
Al Viro9d94b9e2012-12-27 16:52:33 -0500571{
572 struct itimerspec kotmr;
573 int ret = do_timerfd_gettime(ufd, &kotmr);
574 if (ret)
575 return ret;
Heiko Carstens0e803ba2013-03-02 12:26:30 +0100576 return put_compat_itimerspec(otmr, &kotmr) ? -EFAULT: 0;
Al Viro9d94b9e2012-12-27 16:52:33 -0500577}
578#endif