explicitly zero extra buffer space added with realloc to silence valgrind warnings
[project/libubox.git] / uloop.c
1 /*
2  *   Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
3  *   Copyright (C) 2010 John Crispin <blogic@openwrt.org>
4  *   Copyright (C) 2010 Steven Barth <steven@midlink.org>
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
19  *
20  */
21
22 #include <sys/time.h>
23 #include <sys/types.h>
24
25 #include <unistd.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <errno.h>
29 #include <poll.h>
30 #include <string.h>
31 #include <fcntl.h>
32 #include <stdbool.h>
33
34 #include "uloop.h"
35
36 #ifdef USE_KQUEUE
37 #include <sys/event.h>
38 #endif
39 #ifdef USE_EPOLL
40 #include <sys/epoll.h>
41 #endif
42 #include <sys/wait.h>
43
44
45 #ifndef ARRAY_SIZE
46 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
47 #endif
48 #define ULOOP_MAX_EVENTS 10
49
50 static struct list_head timeouts = LIST_HEAD_INIT(timeouts);
51 static struct list_head processes = LIST_HEAD_INIT(processes);
52
53 static int poll_fd = -1;
54 bool uloop_cancelled = false;
55 bool uloop_handle_sigchld = true;
56 static bool do_sigchld = false;
57
58 #ifdef USE_KQUEUE
59
60 int uloop_init(void)
61 {
62         if (poll_fd >= 0)
63                 return 0;
64
65         poll_fd = kqueue();
66         if (poll_fd < 0)
67                 return -1;
68
69         return 0;
70 }
71
72
73 static uint16_t get_flags(unsigned int flags, unsigned int mask)
74 {
75         uint16_t kflags = 0;
76
77         if (!(flags & mask))
78                 return EV_DELETE;
79
80         kflags = EV_ADD;
81         if (flags & ULOOP_EDGE_TRIGGER)
82                 kflags |= EV_CLEAR;
83
84         return kflags;
85 }
86
87 static int register_poll(struct uloop_fd *fd, unsigned int flags)
88 {
89         struct timespec timeout = { 0, 0 };
90         struct kevent ev[2];
91         unsigned int changed;
92         int nev = 0;
93
94         changed = fd->kqflags ^ flags;
95         if (changed & ULOOP_EDGE_TRIGGER)
96                 changed |= flags;
97
98         if (changed & ULOOP_READ) {
99                 uint16_t kflags = get_flags(flags, ULOOP_READ);
100                 EV_SET(&ev[nev++], fd->fd, EVFILT_READ, kflags, 0, 0, fd);
101         }
102
103         if (changed & ULOOP_WRITE) {
104                 uint16_t kflags = get_flags(flags, ULOOP_WRITE);
105                 EV_SET(&ev[nev++], fd->fd, EVFILT_WRITE, kflags, 0, 0, fd);
106         }
107
108         if (nev && (kevent(poll_fd, ev, nev, NULL, 0, &timeout) == -1))
109                 return -1;
110
111         fd->kqflags = flags;
112         return 0;
113 }
114
115 int uloop_fd_delete(struct uloop_fd *sock)
116 {
117         sock->registered = false;
118         return register_poll(sock, 0);
119 }
120
121 static void uloop_run_events(int timeout)
122 {
123         struct kevent events[ULOOP_MAX_EVENTS];
124         struct timespec ts;
125         int nfds, n;
126
127         if (timeout > 0) {
128                 ts.tv_sec = timeout / 1000;
129                 ts.tv_nsec = (timeout % 1000) * 1000000;
130         }
131
132         nfds = kevent(poll_fd, NULL, 0, events, ARRAY_SIZE(events), timeout > 0 ? &ts : NULL);
133         for(n = 0; n < nfds; ++n)
134         {
135                 struct uloop_fd *u = events[n].udata;
136                 unsigned int ev = 0;
137
138                 if(events[n].flags & EV_ERROR) {
139                         u->error = true;
140                         uloop_fd_delete(u);
141                 }
142
143                 if(events[n].filter == EVFILT_READ)
144                         ev |= ULOOP_READ;
145                 else if (events[n].filter == EVFILT_WRITE)
146                         ev |= ULOOP_WRITE;
147
148                 if(events[n].flags & EV_EOF)
149                         u->eof = true;
150                 else if (!ev)
151                         continue;
152
153                 if(u->cb)
154                         u->cb(u, ev);
155         }
156 }
157
158 #endif
159
160 #ifdef USE_EPOLL
161
162 /**
163  * FIXME: uClibc < 0.9.30.3 does not define EPOLLRDHUP for Linux >= 2.6.17
164  */
165 #ifndef EPOLLRDHUP
166 #define EPOLLRDHUP 0x2000
167 #endif
168
169 int uloop_init(void)
170 {
171         if (poll_fd >= 0)
172                 return 0;
173
174         poll_fd = epoll_create(32);
175         if (poll_fd < 0)
176                 return -1;
177
178         fcntl(poll_fd, F_SETFD, fcntl(poll_fd, F_GETFD) | FD_CLOEXEC);
179         return 0;
180 }
181
182 static int register_poll(struct uloop_fd *fd, unsigned int flags)
183 {
184         struct epoll_event ev;
185         int op = fd->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
186
187         memset(&ev, 0, sizeof(struct epoll_event));
188
189         if (flags & ULOOP_READ)
190                 ev.events |= EPOLLIN | EPOLLRDHUP;
191
192         if (flags & ULOOP_WRITE)
193                 ev.events |= EPOLLOUT;
194
195         if (flags & ULOOP_EDGE_TRIGGER)
196                 ev.events |= EPOLLET;
197
198         ev.data.fd = fd->fd;
199         ev.data.ptr = fd;
200
201         return epoll_ctl(poll_fd, op, fd->fd, &ev);
202 }
203
204 int uloop_fd_delete(struct uloop_fd *sock)
205 {
206         sock->registered = false;
207         return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
208 }
209
210 static void uloop_run_events(int timeout)
211 {
212         struct epoll_event events[ULOOP_MAX_EVENTS];
213         int nfds, n;
214
215         nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
216         for(n = 0; n < nfds; ++n)
217         {
218                 struct uloop_fd *u = events[n].data.ptr;
219                 unsigned int ev = 0;
220
221                 if(events[n].events & EPOLLERR) {
222                         u->error = true;
223                         uloop_fd_delete(u);
224                 }
225
226                 if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR)))
227                         continue;
228
229                 if(events[n].events & EPOLLRDHUP)
230                         u->eof = true;
231
232                 if(events[n].events & EPOLLIN)
233                         ev |= ULOOP_READ;
234
235                 if(events[n].events & EPOLLOUT)
236                         ev |= ULOOP_WRITE;
237
238                 if(u->cb)
239                         u->cb(u, ev);
240         }
241 }
242
243 #endif
244
245 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
246 {
247         unsigned int fl;
248         int ret;
249
250         if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
251                 fl = fcntl(sock->fd, F_GETFL, 0);
252                 fl |= O_NONBLOCK;
253                 fcntl(sock->fd, F_SETFL, fl);
254         }
255
256         ret = register_poll(sock, flags);
257         if (ret < 0)
258                 goto out;
259
260         sock->registered = true;
261         sock->eof = false;
262
263 out:
264         return ret;
265 }
266
267 static int tv_diff(struct timeval *t1, struct timeval *t2)
268 {
269         if (t1->tv_sec != t2->tv_sec)
270                 return (t1->tv_sec - t2->tv_sec) * 1000;
271         else
272                 return (t1->tv_usec - t2->tv_usec) / 1000;
273 }
274
275 int uloop_timeout_add(struct uloop_timeout *timeout)
276 {
277         struct uloop_timeout *tmp;
278         struct list_head *h = &timeouts;
279
280         if (timeout->pending)
281                 return -1;
282
283         list_for_each_entry(tmp, &timeouts, list) {
284                 if (tv_diff(&tmp->time, &timeout->time) > 0) {
285                         h = &tmp->list;
286                         break;
287                 }
288         }
289
290         list_add_tail(&timeout->list, h);
291         timeout->pending = true;
292
293         return 0;
294 }
295
296 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
297 {
298         struct timeval *time = &timeout->time;
299
300         if (timeout->pending)
301                 uloop_timeout_cancel(timeout);
302
303         gettimeofday(&timeout->time, NULL);
304
305         time->tv_sec += msecs / 1000;
306         time->tv_usec += msecs % 1000;
307
308         if (time->tv_usec > 1000000) {
309                 time->tv_sec++;
310                 time->tv_usec %= 100000;
311         }
312
313         return uloop_timeout_add(timeout);
314 }
315
316 int uloop_timeout_cancel(struct uloop_timeout *timeout)
317 {
318         if (!timeout->pending)
319                 return -1;
320
321         list_del(&timeout->list);
322         timeout->pending = false;
323
324         return 0;
325 }
326
327 int uloop_process_add(struct uloop_process *p)
328 {
329         struct uloop_process *tmp;
330         struct list_head *h = &processes;
331
332         if (p->pending)
333                 return -1;
334
335         list_for_each_entry(tmp, &processes, list) {
336                 if (tmp->pid > p->pid) {
337                         h = &tmp->list;
338                         break;
339                 }
340         }
341
342         list_add_tail(&p->list, h);
343         p->pending = true;
344
345         return 0;
346 }
347
348 int uloop_process_delete(struct uloop_process *p)
349 {
350         if (!p->pending)
351                 return -1;
352
353         list_del(&p->list);
354         p->pending = false;
355
356         return 0;
357 }
358
359 static void uloop_handle_processes(void)
360 {
361         struct uloop_process *p, *tmp;
362         pid_t pid;
363         int ret;
364
365         do_sigchld = false;
366
367         while (1) {
368                 pid = waitpid(-1, &ret, WNOHANG);
369                 if (pid <= 0)
370                         return;
371
372                 list_for_each_entry_safe(p, tmp, &processes, list) {
373                         if (p->pid < pid)
374                                 continue;
375
376                         if (p->pid > pid)
377                                 break;
378
379                         uloop_process_delete(p);
380                         p->cb(p, ret);
381                 }
382         }
383
384 }
385
386 static void uloop_handle_sigint(int signo)
387 {
388         uloop_cancelled = true;
389 }
390
391 static void uloop_sigchld(int signo)
392 {
393         do_sigchld = true;
394 }
395
396 static void uloop_setup_signals(void)
397 {
398         struct sigaction s;
399
400         memset(&s, 0, sizeof(struct sigaction));
401         s.sa_handler = uloop_handle_sigint;
402         s.sa_flags = 0;
403         sigaction(SIGINT, &s, NULL);
404
405         if (uloop_handle_sigchld) {
406                 s.sa_handler = uloop_sigchld;
407                 sigaction(SIGCHLD, &s, NULL);
408         }
409 }
410
411 static int uloop_get_next_timeout(struct timeval *tv)
412 {
413         struct uloop_timeout *timeout;
414         int diff;
415
416         if (list_empty(&timeouts))
417                 return -1;
418
419         timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
420         diff = tv_diff(&timeout->time, tv);
421         if (diff < 0)
422                 return 0;
423
424         return diff;
425 }
426
427 static void uloop_process_timeouts(struct timeval *tv)
428 {
429         struct uloop_timeout *t, *tmp;
430
431         list_for_each_entry_safe(t, tmp, &timeouts, list) {
432                 if (tv_diff(&t->time, tv) > 0)
433                         break;
434
435                 uloop_timeout_cancel(t);
436                 if (t->cb)
437                         t->cb(t);
438         }
439 }
440
441 void uloop_run(void)
442 {
443         struct timeval tv;
444
445         uloop_setup_signals();
446         while(!uloop_cancelled)
447         {
448                 gettimeofday(&tv, NULL);
449                 uloop_process_timeouts(&tv);
450                 if (uloop_cancelled)
451                         break;
452
453                 if (do_sigchld)
454                         uloop_handle_processes();
455                 uloop_run_events(uloop_get_next_timeout(&tv));
456         }
457 }
458
459 void uloop_done(void)
460 {
461         if (poll_fd < 0)
462                 return;
463
464         close(poll_fd);
465         poll_fd = -1;
466 }