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460b9539 | 1 | /* |
2 | * This file is part of DisOrder. | |
964e027d | 3 | * Copyright (C) 2004, 2005, 2007, 2008 Richard Kettlewell |
460b9539 | 4 | * |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but | |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 | |
18 | * USA | |
19 | */ | |
768d7355 RK |
20 | /** @file lib/event.c |
21 | * @brief DisOrder event loop | |
22 | */ | |
460b9539 | 23 | |
05b75f8d | 24 | #include "common.h" |
460b9539 | 25 | |
26 | #include <unistd.h> | |
27 | #include <fcntl.h> | |
28 | #include <sys/time.h> | |
29 | #include <sys/types.h> | |
30 | #include <sys/resource.h> | |
31 | #include <sys/wait.h> | |
46bd8db4 | 32 | #include <sys/stat.h> |
460b9539 | 33 | #include <unistd.h> |
460b9539 | 34 | #include <signal.h> |
35 | #include <errno.h> | |
460b9539 | 36 | #include <sys/socket.h> |
37 | #include <netinet/in.h> | |
38 | #include <sys/un.h> | |
460b9539 | 39 | #include "event.h" |
40 | #include "mem.h" | |
41 | #include "log.h" | |
42 | #include "syscalls.h" | |
43 | #include "printf.h" | |
44 | #include "sink.h" | |
768d7355 | 45 | #include "vector.h" |
3af7813d RK |
46 | #include "timeval.h" |
47 | #include "heap.h" | |
460b9539 | 48 | |
768d7355 | 49 | /** @brief A timeout */ |
460b9539 | 50 | struct timeout { |
51 | struct timeout *next; | |
52 | struct timeval when; | |
53 | ev_timeout_callback *callback; | |
54 | void *u; | |
3af7813d | 55 | int active; |
460b9539 | 56 | }; |
57 | ||
3af7813d RK |
58 | /** @brief Comparison function for timeouts */ |
59 | static int timeout_lt(const struct timeout *a, | |
60 | const struct timeout *b) { | |
61 | return tvlt(&a->when, &b->when); | |
62 | } | |
63 | ||
64 | HEAP_TYPE(timeout_heap, struct timeout *, timeout_lt); | |
65 | HEAP_DEFINE(timeout_heap, struct timeout *, timeout_lt); | |
66 | ||
768d7355 | 67 | /** @brief A file descriptor in one mode */ |
460b9539 | 68 | struct fd { |
69 | int fd; | |
70 | ev_fd_callback *callback; | |
71 | void *u; | |
e8c92ba7 | 72 | const char *what; |
460b9539 | 73 | }; |
74 | ||
768d7355 | 75 | /** @brief All the file descriptors in a given mode */ |
460b9539 | 76 | struct fdmode { |
768d7355 | 77 | /** @brief Mask of active file descriptors passed to @c select() */ |
460b9539 | 78 | fd_set enabled; |
768d7355 RK |
79 | |
80 | /** @brief File descriptor mask returned from @c select() */ | |
460b9539 | 81 | fd_set tripped; |
768d7355 RK |
82 | |
83 | /** @brief Number of file descriptors in @p fds */ | |
84 | int nfds; | |
85 | ||
86 | /** @brief Number of slots in @p fds */ | |
87 | int fdslots; | |
88 | ||
89 | /** @brief Array of all active file descriptors */ | |
460b9539 | 90 | struct fd *fds; |
768d7355 RK |
91 | |
92 | /** @brief Highest-numbered file descriptor or 0 */ | |
460b9539 | 93 | int maxfd; |
94 | }; | |
95 | ||
768d7355 | 96 | /** @brief A signal handler */ |
460b9539 | 97 | struct signal { |
98 | struct sigaction oldsa; | |
99 | ev_signal_callback *callback; | |
100 | void *u; | |
101 | }; | |
102 | ||
768d7355 | 103 | /** @brief A child process */ |
460b9539 | 104 | struct child { |
105 | pid_t pid; | |
106 | int options; | |
107 | ev_child_callback *callback; | |
108 | void *u; | |
109 | }; | |
110 | ||
768d7355 | 111 | /** @brief An event loop */ |
460b9539 | 112 | struct ev_source { |
768d7355 | 113 | /** @brief File descriptors, per mode */ |
460b9539 | 114 | struct fdmode mode[ev_nmodes]; |
768d7355 | 115 | |
3af7813d RK |
116 | /** @brief Heap of timeouts */ |
117 | struct timeout_heap timeouts[1]; | |
768d7355 RK |
118 | |
119 | /** @brief Array of handled signals */ | |
460b9539 | 120 | struct signal signals[NSIG]; |
768d7355 RK |
121 | |
122 | /** @brief Mask of handled signals */ | |
460b9539 | 123 | sigset_t sigmask; |
768d7355 RK |
124 | |
125 | /** @brief Escape early from handling of @c select() results | |
126 | * | |
127 | * This is set if any of the file descriptor arrays are invalidated, since | |
128 | * it's then not safe for processing of them to continue. | |
129 | */ | |
460b9539 | 130 | int escape; |
768d7355 RK |
131 | |
132 | /** @brief Signal handling pipe | |
133 | * | |
134 | * The signal handle writes signal numbers down this pipe. | |
135 | */ | |
460b9539 | 136 | int sigpipe[2]; |
768d7355 RK |
137 | |
138 | /** @brief Number of child processes in @p children */ | |
139 | int nchildren; | |
140 | ||
141 | /** @brief Number of slots in @p children */ | |
142 | int nchildslots; | |
143 | ||
144 | /** @brief Array of child processes */ | |
460b9539 | 145 | struct child *children; |
146 | }; | |
147 | ||
768d7355 | 148 | /** @brief Names of file descriptor modes */ |
460b9539 | 149 | static const char *modenames[] = { "read", "write", "except" }; |
150 | ||
151 | /* utilities ******************************************************************/ | |
152 | ||
460b9539 | 153 | /* creation *******************************************************************/ |
154 | ||
768d7355 | 155 | /** @brief Create a new event loop */ |
460b9539 | 156 | ev_source *ev_new(void) { |
157 | ev_source *ev = xmalloc(sizeof *ev); | |
158 | int n; | |
159 | ||
160 | memset(ev, 0, sizeof *ev); | |
161 | for(n = 0; n < ev_nmodes; ++n) | |
162 | FD_ZERO(&ev->mode[n].enabled); | |
163 | ev->sigpipe[0] = ev->sigpipe[1] = -1; | |
164 | sigemptyset(&ev->sigmask); | |
3af7813d | 165 | timeout_heap_init(ev->timeouts); |
460b9539 | 166 | return ev; |
167 | } | |
168 | ||
169 | /* event loop *****************************************************************/ | |
170 | ||
768d7355 RK |
171 | /** @brief Run the event loop |
172 | * @return -1 on error, non-0 if any callback returned non-0 | |
173 | */ | |
460b9539 | 174 | int ev_run(ev_source *ev) { |
175 | for(;;) { | |
176 | struct timeval now; | |
177 | struct timeval delta; | |
178 | int n, mode; | |
179 | int ret; | |
180 | int maxfd; | |
3af7813d | 181 | struct timeout *timeouts, *t, **tt; |
e8c92ba7 | 182 | struct stat sb; |
460b9539 | 183 | |
184 | xgettimeofday(&now, 0); | |
185 | /* Handle timeouts. We don't want to handle any timeouts that are added | |
186 | * while we're handling them (otherwise we'd have to break out of infinite | |
187 | * loops, preferrably without starving better-behaved subsystems). Hence | |
188 | * the slightly complicated two-phase approach here. */ | |
3af7813d RK |
189 | /* First we read those timeouts that have triggered out of the heap. We |
190 | * keep them in the same order they came out of the heap in. */ | |
191 | tt = &timeouts; | |
192 | while(timeout_heap_count(ev->timeouts) | |
193 | && tvle(&timeout_heap_first(ev->timeouts)->when, &now)) { | |
194 | /* This timeout has reached its trigger time; provided it has not been | |
195 | * cancelled we add it to the timeouts list. */ | |
196 | t = timeout_heap_remove(ev->timeouts); | |
197 | if(t->active) { | |
198 | *tt = t; | |
199 | tt = &t->next; | |
200 | } | |
201 | } | |
202 | *tt = 0; | |
203 | /* Now we can run the callbacks for those timeouts. They might add further | |
204 | * timeouts that are already in the past but they won't trigger until the | |
205 | * next time round the event loop. */ | |
206 | for(t = timeouts; t; t = t->next) { | |
460b9539 | 207 | D(("calling timeout for %ld.%ld callback %p %p", |
208 | (long)t->when.tv_sec, (long)t->when.tv_usec, | |
209 | (void *)t->callback, t->u)); | |
210 | ret = t->callback(ev, &now, t->u); | |
211 | if(ret) | |
212 | return ret; | |
213 | } | |
460b9539 | 214 | maxfd = 0; |
215 | for(mode = 0; mode < ev_nmodes; ++mode) { | |
216 | ev->mode[mode].tripped = ev->mode[mode].enabled; | |
217 | if(ev->mode[mode].maxfd > maxfd) | |
218 | maxfd = ev->mode[mode].maxfd; | |
219 | } | |
220 | xsigprocmask(SIG_UNBLOCK, &ev->sigmask, 0); | |
221 | do { | |
3af7813d RK |
222 | if(timeout_heap_count(ev->timeouts)) { |
223 | t = timeout_heap_first(ev->timeouts); | |
460b9539 | 224 | xgettimeofday(&now, 0); |
3af7813d RK |
225 | delta.tv_sec = t->when.tv_sec - now.tv_sec; |
226 | delta.tv_usec = t->when.tv_usec - now.tv_usec; | |
460b9539 | 227 | if(delta.tv_usec < 0) { |
228 | delta.tv_usec += 1000000; | |
229 | --delta.tv_sec; | |
230 | } | |
231 | if(delta.tv_sec < 0) | |
232 | delta.tv_sec = delta.tv_usec = 0; | |
233 | n = select(maxfd + 1, | |
234 | &ev->mode[ev_read].tripped, | |
235 | &ev->mode[ev_write].tripped, | |
236 | &ev->mode[ev_except].tripped, | |
237 | &delta); | |
238 | } else { | |
239 | n = select(maxfd + 1, | |
240 | &ev->mode[ev_read].tripped, | |
241 | &ev->mode[ev_write].tripped, | |
242 | &ev->mode[ev_except].tripped, | |
243 | 0); | |
244 | } | |
245 | } while(n < 0 && errno == EINTR); | |
246 | xsigprocmask(SIG_BLOCK, &ev->sigmask, 0); | |
247 | if(n < 0) { | |
248 | error(errno, "error calling select"); | |
e8c92ba7 RK |
249 | if(errno == EBADF) { |
250 | /* If there's a bad FD in the mix then check them all and log what we | |
251 | * find, to ease debugging */ | |
252 | for(mode = 0; mode < ev_nmodes; ++mode) { | |
253 | for(n = 0; n < ev->mode[mode].nfds; ++n) { | |
254 | const int fd = ev->mode[mode].fds[n].fd; | |
255 | ||
256 | if(FD_ISSET(fd, &ev->mode[mode].enabled) | |
257 | && fstat(fd, &sb) < 0) | |
34a3e246 RK |
258 | error(errno, "mode %s fstat %d (%s)", |
259 | modenames[mode], fd, ev->mode[mode].fds[n].what); | |
e8c92ba7 | 260 | } |
7958ad2f | 261 | for(n = 0; n <= maxfd; ++n) |
34a3e246 RK |
262 | if(FD_ISSET(n, &ev->mode[mode].enabled) |
263 | && fstat(n, &sb) < 0) | |
264 | error(errno, "mode %s fstat %d", modenames[mode], n); | |
e8c92ba7 RK |
265 | } |
266 | } | |
460b9539 | 267 | return -1; |
268 | } | |
269 | if(n > 0) { | |
270 | /* if anything deranges the meaning of an fd, or re-orders the | |
271 | * fds[] tables, we'd better give up; such operations will | |
272 | * therefore set @escape@. */ | |
273 | ev->escape = 0; | |
274 | for(mode = 0; mode < ev_nmodes && !ev->escape; ++mode) | |
275 | for(n = 0; n < ev->mode[mode].nfds && !ev->escape; ++n) { | |
276 | int fd = ev->mode[mode].fds[n].fd; | |
277 | if(FD_ISSET(fd, &ev->mode[mode].tripped)) { | |
278 | D(("calling %s fd %d callback %p %p", modenames[mode], fd, | |
279 | (void *)ev->mode[mode].fds[n].callback, | |
280 | ev->mode[mode].fds[n].u)); | |
281 | ret = ev->mode[mode].fds[n].callback(ev, fd, | |
282 | ev->mode[mode].fds[n].u); | |
283 | if(ret) | |
284 | return ret; | |
285 | } | |
286 | } | |
287 | } | |
288 | /* we'll pick up timeouts back round the loop */ | |
289 | } | |
290 | } | |
291 | ||
292 | /* file descriptors ***********************************************************/ | |
293 | ||
768d7355 RK |
294 | /** @brief Register a file descriptor |
295 | * @param ev Event loop | |
296 | * @param mode @c ev_read or @c ev_write | |
297 | * @param fd File descriptor | |
298 | * @param callback Called when @p is readable/writable | |
299 | * @param u Passed to @p callback | |
300 | * @param what Text description | |
301 | * @return 0 on success, non-0 on error | |
302 | * | |
303 | * Sets @ref ev_source::escape, so no further processing of file descriptors | |
304 | * will occur this time round the event loop. | |
305 | */ | |
460b9539 | 306 | int ev_fd(ev_source *ev, |
307 | ev_fdmode mode, | |
308 | int fd, | |
309 | ev_fd_callback *callback, | |
e8c92ba7 RK |
310 | void *u, |
311 | const char *what) { | |
460b9539 | 312 | int n; |
313 | ||
314 | D(("registering %s fd %d callback %p %p", modenames[mode], fd, | |
315 | (void *)callback, u)); | |
316 | assert(mode < ev_nmodes); | |
317 | if(ev->mode[mode].nfds >= ev->mode[mode].fdslots) { | |
318 | ev->mode[mode].fdslots = (ev->mode[mode].fdslots | |
319 | ? 2 * ev->mode[mode].fdslots : 16); | |
320 | D(("expanding %s fd table to %d entries", modenames[mode], | |
321 | ev->mode[mode].fdslots)); | |
322 | ev->mode[mode].fds = xrealloc(ev->mode[mode].fds, | |
323 | ev->mode[mode].fdslots * sizeof (struct fd)); | |
324 | } | |
325 | n = ev->mode[mode].nfds++; | |
326 | FD_SET(fd, &ev->mode[mode].enabled); | |
327 | ev->mode[mode].fds[n].fd = fd; | |
328 | ev->mode[mode].fds[n].callback = callback; | |
329 | ev->mode[mode].fds[n].u = u; | |
e8c92ba7 | 330 | ev->mode[mode].fds[n].what = what; |
460b9539 | 331 | if(fd > ev->mode[mode].maxfd) |
332 | ev->mode[mode].maxfd = fd; | |
333 | ev->escape = 1; | |
334 | return 0; | |
335 | } | |
336 | ||
768d7355 RK |
337 | /** @brief Cancel a file descriptor |
338 | * @param ev Event loop | |
339 | * @param mode @c ev_read or @c ev_write | |
340 | * @param fd File descriptor | |
341 | * @return 0 on success, non-0 on error | |
342 | * | |
343 | * Sets @ref ev_source::escape, so no further processing of file descriptors | |
344 | * will occur this time round the event loop. | |
345 | */ | |
460b9539 | 346 | int ev_fd_cancel(ev_source *ev, ev_fdmode mode, int fd) { |
347 | int n; | |
348 | int maxfd; | |
349 | ||
350 | D(("cancelling mode %s fd %d", modenames[mode], fd)); | |
351 | /* find the right struct fd */ | |
352 | for(n = 0; n < ev->mode[mode].nfds && fd != ev->mode[mode].fds[n].fd; ++n) | |
353 | ; | |
354 | assert(n < ev->mode[mode].nfds); | |
355 | /* swap in the last fd and reduce the count */ | |
356 | if(n != ev->mode[mode].nfds - 1) | |
357 | ev->mode[mode].fds[n] = ev->mode[mode].fds[ev->mode[mode].nfds - 1]; | |
358 | --ev->mode[mode].nfds; | |
359 | /* if that was the biggest fd, find the new biggest one */ | |
360 | if(fd == ev->mode[mode].maxfd) { | |
361 | maxfd = 0; | |
362 | for(n = 0; n < ev->mode[mode].nfds; ++n) | |
363 | if(ev->mode[mode].fds[n].fd > maxfd) | |
364 | maxfd = ev->mode[mode].fds[n].fd; | |
365 | ev->mode[mode].maxfd = maxfd; | |
366 | } | |
367 | /* don't tell select about this fd any more */ | |
368 | FD_CLR(fd, &ev->mode[mode].enabled); | |
369 | ev->escape = 1; | |
370 | return 0; | |
371 | } | |
372 | ||
768d7355 RK |
373 | /** @brief Re-enable a file descriptor |
374 | * @param ev Event loop | |
375 | * @param mode @c ev_read or @c ev_write | |
376 | * @param fd File descriptor | |
377 | * @return 0 on success, non-0 on error | |
378 | * | |
379 | * It is harmless if @p fd is currently disabled, but it must not have been | |
380 | * cancelled. | |
381 | */ | |
460b9539 | 382 | int ev_fd_enable(ev_source *ev, ev_fdmode mode, int fd) { |
38b8221f | 383 | assert(fd >= 0); |
460b9539 | 384 | D(("enabling mode %s fd %d", modenames[mode], fd)); |
385 | FD_SET(fd, &ev->mode[mode].enabled); | |
386 | return 0; | |
387 | } | |
388 | ||
768d7355 RK |
389 | /** @brief Temporarily disable a file descriptor |
390 | * @param ev Event loop | |
391 | * @param mode @c ev_read or @c ev_write | |
392 | * @param fd File descriptor | |
393 | * @return 0 on success, non-0 on error | |
394 | * | |
395 | * Re-enable with ev_fd_enable(). It is harmless if @p fd is already disabled, | |
396 | * but it must not have been cancelled. | |
397 | */ | |
460b9539 | 398 | int ev_fd_disable(ev_source *ev, ev_fdmode mode, int fd) { |
399 | D(("disabling mode %s fd %d", modenames[mode], fd)); | |
400 | FD_CLR(fd, &ev->mode[mode].enabled); | |
401 | FD_CLR(fd, &ev->mode[mode].tripped); | |
75d64210 RK |
402 | /* Suppress any pending callbacks */ |
403 | ev->escape = 1; | |
460b9539 | 404 | return 0; |
405 | } | |
406 | ||
768d7355 RK |
407 | /** @brief Log a report of file descriptor state */ |
408 | void ev_report(ev_source *ev) { | |
409 | int n, fd; | |
410 | ev_fdmode mode; | |
411 | struct dynstr d[1]; | |
412 | char b[4096]; | |
413 | ||
0fa83caa RK |
414 | if(!debugging) |
415 | return; | |
768d7355 RK |
416 | dynstr_init(d); |
417 | for(mode = 0; mode < ev_nmodes; ++mode) { | |
0fa83caa | 418 | D(("mode %s maxfd %d", modenames[mode], ev->mode[mode].maxfd)); |
768d7355 RK |
419 | for(n = 0; n < ev->mode[mode].nfds; ++n) { |
420 | fd = ev->mode[mode].fds[n].fd; | |
0fa83caa RK |
421 | D(("fd %s %d%s%s (%s)", modenames[mode], fd, |
422 | FD_ISSET(fd, &ev->mode[mode].enabled) ? " enabled" : "", | |
423 | FD_ISSET(fd, &ev->mode[mode].tripped) ? " tripped" : "", | |
424 | ev->mode[mode].fds[n].what)); | |
768d7355 RK |
425 | } |
426 | d->nvec = 0; | |
427 | for(fd = 0; fd <= ev->mode[mode].maxfd; ++fd) { | |
428 | if(!FD_ISSET(fd, &ev->mode[mode].enabled)) | |
429 | continue; | |
430 | for(n = 0; n < ev->mode[mode].nfds; ++n) { | |
431 | if(ev->mode[mode].fds[n].fd == fd) | |
432 | break; | |
433 | } | |
434 | if(n < ev->mode[mode].nfds) | |
34a3e246 | 435 | snprintf(b, sizeof b, "%d(%s)", fd, ev->mode[mode].fds[n].what); |
768d7355 | 436 | else |
34a3e246 | 437 | snprintf(b, sizeof b, "%d", fd); |
768d7355 RK |
438 | dynstr_append(d, ' '); |
439 | dynstr_append_string(d, b); | |
440 | } | |
441 | dynstr_terminate(d); | |
0fa83caa | 442 | D(("%s enabled:%s", modenames[mode], d->vec)); |
768d7355 RK |
443 | } |
444 | } | |
445 | ||
460b9539 | 446 | /* timeouts *******************************************************************/ |
447 | ||
768d7355 RK |
448 | /** @brief Register a timeout |
449 | * @param ev Event source | |
3149c1e2 | 450 | * @param handlep Where to store timeout handle, or @c NULL |
768d7355 RK |
451 | * @param when Earliest time to call @p callback, or @c NULL |
452 | * @param callback Function to call at or after @p when | |
453 | * @param u Passed to @p callback | |
454 | * @return 0 on success, non-0 on error | |
455 | * | |
456 | * If @p when is a null pointer then a time of 0 is assumed. The effect is to | |
457 | * call the timeout handler from ev_run() next time around the event loop. | |
458 | * This is used internally to schedule various operations if it is not | |
459 | * convenient to call them from the current place in the call stack, or | |
460 | * externally to ensure that other clients of the event loop get a look in when | |
461 | * performing some lengthy operation. | |
462 | */ | |
460b9539 | 463 | int ev_timeout(ev_source *ev, |
464 | ev_timeout_handle *handlep, | |
465 | const struct timeval *when, | |
466 | ev_timeout_callback *callback, | |
467 | void *u) { | |
3af7813d | 468 | struct timeout *t; |
460b9539 | 469 | |
470 | D(("registering timeout at %ld.%ld callback %p %p", | |
471 | when ? (long)when->tv_sec : 0, when ? (long)when->tv_usec : 0, | |
472 | (void *)callback, u)); | |
473 | t = xmalloc(sizeof *t); | |
474 | if(when) | |
475 | t->when = *when; | |
476 | t->callback = callback; | |
477 | t->u = u; | |
3af7813d RK |
478 | t->active = 1; |
479 | timeout_heap_insert(ev->timeouts, t); | |
460b9539 | 480 | if(handlep) |
481 | *handlep = t; | |
482 | return 0; | |
483 | } | |
484 | ||
768d7355 RK |
485 | /** @brief Cancel a timeout |
486 | * @param ev Event loop | |
cb9a695c | 487 | * @param handle Handle returned from ev_timeout(), or 0 |
768d7355 | 488 | * @return 0 on success, non-0 on error |
cb9a695c RK |
489 | * |
490 | * If @p handle is 0 then this is a no-op. | |
768d7355 | 491 | */ |
3af7813d | 492 | int ev_timeout_cancel(ev_source attribute((unused)) *ev, |
460b9539 | 493 | ev_timeout_handle handle) { |
3af7813d | 494 | struct timeout *t = handle; |
460b9539 | 495 | |
3af7813d RK |
496 | if(t) |
497 | t->active = 0; | |
498 | return 0; | |
460b9539 | 499 | } |
500 | ||
501 | /* signals ********************************************************************/ | |
502 | ||
768d7355 RK |
503 | /** @brief Mapping of signals to pipe write ends |
504 | * | |
505 | * The pipes are per-event loop, it's possible in theory for there to be | |
506 | * multiple event loops (e.g. in different threads), although in fact DisOrder | |
507 | * does not do this. | |
508 | */ | |
460b9539 | 509 | static int sigfd[NSIG]; |
510 | ||
768d7355 RK |
511 | /** @brief The signal handler |
512 | * @param s Signal number | |
513 | * | |
514 | * Writes to @c sigfd[s]. | |
515 | */ | |
460b9539 | 516 | static void sighandler(int s) { |
517 | unsigned char sc = s; | |
518 | static const char errmsg[] = "error writing to signal pipe"; | |
519 | ||
520 | /* probably the reader has stopped listening for some reason */ | |
521 | if(write(sigfd[s], &sc, 1) < 0) { | |
522 | write(2, errmsg, sizeof errmsg - 1); | |
523 | abort(); | |
524 | } | |
525 | } | |
526 | ||
768d7355 | 527 | /** @brief Read callback for signals */ |
460b9539 | 528 | static int signal_read(ev_source *ev, |
529 | int attribute((unused)) fd, | |
530 | void attribute((unused)) *u) { | |
531 | unsigned char s; | |
532 | int n; | |
533 | int ret; | |
534 | ||
535 | if((n = read(ev->sigpipe[0], &s, 1)) == 1) | |
536 | if((ret = ev->signals[s].callback(ev, s, ev->signals[s].u))) | |
537 | return ret; | |
538 | assert(n != 0); | |
539 | if(n < 0 && (errno != EINTR && errno != EAGAIN)) { | |
540 | error(errno, "error reading from signal pipe %d", ev->sigpipe[0]); | |
541 | return -1; | |
542 | } | |
543 | return 0; | |
544 | } | |
545 | ||
768d7355 | 546 | /** @brief Close the signal pipe */ |
460b9539 | 547 | static void close_sigpipe(ev_source *ev) { |
548 | int save_errno = errno; | |
549 | ||
550 | xclose(ev->sigpipe[0]); | |
551 | xclose(ev->sigpipe[1]); | |
552 | ev->sigpipe[0] = ev->sigpipe[1] = -1; | |
553 | errno = save_errno; | |
554 | } | |
555 | ||
768d7355 RK |
556 | /** @brief Register a signal handler |
557 | * @param ev Event loop | |
558 | * @param sig Signal to handle | |
559 | * @param callback Called when signal is delivered | |
560 | * @param u Passed to @p callback | |
561 | * @return 0 on success, non-0 on error | |
562 | * | |
563 | * Note that @p callback is called from inside ev_run(), not from inside the | |
564 | * signal handler, so the usual restrictions on signal handlers do not apply. | |
565 | */ | |
460b9539 | 566 | int ev_signal(ev_source *ev, |
567 | int sig, | |
568 | ev_signal_callback *callback, | |
569 | void *u) { | |
570 | int n; | |
571 | struct sigaction sa; | |
572 | ||
573 | D(("registering signal %d handler callback %p %p", sig, (void *)callback, u)); | |
574 | assert(sig > 0); | |
575 | assert(sig < NSIG); | |
576 | assert(sig <= UCHAR_MAX); | |
577 | if(ev->sigpipe[0] == -1) { | |
578 | D(("creating signal pipe")); | |
579 | xpipe(ev->sigpipe); | |
580 | D(("signal pipe is %d, %d", ev->sigpipe[0], ev->sigpipe[1])); | |
581 | for(n = 0; n < 2; ++n) { | |
582 | nonblock(ev->sigpipe[n]); | |
583 | cloexec(ev->sigpipe[n]); | |
584 | } | |
e8c92ba7 | 585 | if(ev_fd(ev, ev_read, ev->sigpipe[0], signal_read, 0, "sigpipe read")) { |
460b9539 | 586 | close_sigpipe(ev); |
587 | return -1; | |
588 | } | |
589 | } | |
590 | sigaddset(&ev->sigmask, sig); | |
591 | xsigprocmask(SIG_BLOCK, &ev->sigmask, 0); | |
592 | sigfd[sig] = ev->sigpipe[1]; | |
593 | ev->signals[sig].callback = callback; | |
594 | ev->signals[sig].u = u; | |
595 | sa.sa_handler = sighandler; | |
596 | sigfillset(&sa.sa_mask); | |
597 | sa.sa_flags = SA_RESTART; | |
598 | xsigaction(sig, &sa, &ev->signals[sig].oldsa); | |
599 | ev->escape = 1; | |
600 | return 0; | |
601 | } | |
602 | ||
768d7355 RK |
603 | /** @brief Cancel a signal handler |
604 | * @param ev Event loop | |
605 | * @param sig Signal to cancel | |
606 | * @return 0 on success, non-0 on error | |
607 | */ | |
460b9539 | 608 | int ev_signal_cancel(ev_source *ev, |
609 | int sig) { | |
610 | sigset_t ss; | |
611 | ||
612 | xsigaction(sig, &ev->signals[sig].oldsa, 0); | |
613 | ev->signals[sig].callback = 0; | |
614 | ev->escape = 1; | |
615 | sigdelset(&ev->sigmask, sig); | |
616 | sigemptyset(&ss); | |
617 | sigaddset(&ss, sig); | |
618 | xsigprocmask(SIG_UNBLOCK, &ss, 0); | |
619 | return 0; | |
620 | } | |
621 | ||
768d7355 RK |
622 | /** @brief Clean up signal handling |
623 | * @param ev Event loop | |
624 | * | |
625 | * This function can be called from inside a fork. It restores signal | |
626 | * handlers, unblocks the signals, and closes the signal pipe for @p ev. | |
627 | */ | |
460b9539 | 628 | void ev_signal_atfork(ev_source *ev) { |
629 | int sig; | |
630 | ||
631 | if(ev->sigpipe[0] != -1) { | |
632 | /* revert any handled signals to their original state */ | |
633 | for(sig = 1; sig < NSIG; ++sig) { | |
634 | if(ev->signals[sig].callback != 0) | |
635 | xsigaction(sig, &ev->signals[sig].oldsa, 0); | |
636 | } | |
637 | /* and then unblock them */ | |
638 | xsigprocmask(SIG_UNBLOCK, &ev->sigmask, 0); | |
639 | /* don't want a copy of the signal pipe open inside the fork */ | |
640 | xclose(ev->sigpipe[0]); | |
641 | xclose(ev->sigpipe[1]); | |
642 | } | |
643 | } | |
644 | ||
645 | /* child processes ************************************************************/ | |
646 | ||
768d7355 | 647 | /** @brief Called on SIGCHLD */ |
460b9539 | 648 | static int sigchld_callback(ev_source *ev, |
649 | int attribute((unused)) sig, | |
650 | void attribute((unused)) *u) { | |
651 | struct rusage ru; | |
652 | pid_t r; | |
653 | int status, n, ret, revisit; | |
654 | ||
655 | do { | |
656 | revisit = 0; | |
657 | for(n = 0; n < ev->nchildren; ++n) { | |
658 | r = wait4(ev->children[n].pid, | |
659 | &status, | |
660 | ev->children[n].options | WNOHANG, | |
661 | &ru); | |
662 | if(r > 0) { | |
663 | ev_child_callback *c = ev->children[n].callback; | |
664 | void *cu = ev->children[n].u; | |
665 | ||
666 | if(WIFEXITED(status) || WIFSIGNALED(status)) | |
667 | ev_child_cancel(ev, r); | |
668 | revisit = 1; | |
669 | if((ret = c(ev, r, status, &ru, cu))) | |
670 | return ret; | |
671 | } else if(r < 0) { | |
672 | /* We should "never" get an ECHILD but it can in fact happen. For | |
673 | * instance on Linux 2.4.31, and probably other versions, if someone | |
674 | * straces a child process and then a different child process | |
675 | * terminates, when we wait4() the trace process we will get ECHILD | |
676 | * because it has been reparented to strace. Obviously this is a | |
677 | * hopeless design flaw in the tracing infrastructure, but we don't | |
678 | * want the disorder server to bomb out because of it. So we just log | |
679 | * the problem and ignore it. | |
680 | */ | |
681 | error(errno, "error calling wait4 for PID %lu (broken ptrace?)", | |
682 | (unsigned long)ev->children[n].pid); | |
683 | if(errno != ECHILD) | |
684 | return -1; | |
685 | } | |
686 | } | |
687 | } while(revisit); | |
688 | return 0; | |
689 | } | |
690 | ||
768d7355 RK |
691 | /** @brief Configure event loop for child process handling |
692 | * @return 0 on success, non-0 on error | |
693 | * | |
694 | * Currently at most one event loop can handle child processes and it must be | |
695 | * distinguished from others by calling this function on it. This could be | |
696 | * fixed but since no process ever makes use of more than one event loop there | |
697 | * is no need. | |
698 | */ | |
460b9539 | 699 | int ev_child_setup(ev_source *ev) { |
700 | D(("installing SIGCHLD handler")); | |
701 | return ev_signal(ev, SIGCHLD, sigchld_callback, 0); | |
702 | } | |
703 | ||
768d7355 RK |
704 | /** @brief Wait for a child process to terminate |
705 | * @param ev Event loop | |
706 | * @param pid Process ID of child | |
707 | * @param options Options to pass to @c wait4() | |
708 | * @param callback Called when child terminates (or possibly when it stops) | |
709 | * @param u Passed to @p callback | |
710 | * @return 0 on success, non-0 on error | |
711 | * | |
712 | * You must have called ev_child_setup() on @p ev once first. | |
713 | */ | |
460b9539 | 714 | int ev_child(ev_source *ev, |
715 | pid_t pid, | |
716 | int options, | |
717 | ev_child_callback *callback, | |
718 | void *u) { | |
719 | int n; | |
720 | ||
721 | D(("registering child handling %ld options %d callback %p %p", | |
722 | (long)pid, options, (void *)callback, u)); | |
723 | assert(ev->signals[SIGCHLD].callback == sigchld_callback); | |
724 | if(ev->nchildren >= ev->nchildslots) { | |
725 | ev->nchildslots = ev->nchildslots ? 2 * ev->nchildslots : 16; | |
726 | ev->children = xrealloc(ev->children, | |
727 | ev->nchildslots * sizeof (struct child)); | |
728 | } | |
729 | n = ev->nchildren++; | |
730 | ev->children[n].pid = pid; | |
731 | ev->children[n].options = options; | |
732 | ev->children[n].callback = callback; | |
733 | ev->children[n].u = u; | |
734 | return 0; | |
735 | } | |
736 | ||
768d7355 RK |
737 | /** @brief Stop waiting for a child process |
738 | * @param ev Event loop | |
739 | * @param pid Child process ID | |
740 | * @return 0 on success, non-0 on error | |
741 | */ | |
460b9539 | 742 | int ev_child_cancel(ev_source *ev, |
743 | pid_t pid) { | |
744 | int n; | |
745 | ||
746 | for(n = 0; n < ev->nchildren && ev->children[n].pid != pid; ++n) | |
747 | ; | |
748 | assert(n < ev->nchildren); | |
749 | if(n != ev->nchildren - 1) | |
750 | ev->children[n] = ev->children[ev->nchildren - 1]; | |
751 | --ev->nchildren; | |
752 | return 0; | |
753 | } | |
754 | ||
755 | /* socket listeners ***********************************************************/ | |
756 | ||
768d7355 | 757 | /** @brief State for a socket listener */ |
460b9539 | 758 | struct listen_state { |
759 | ev_listen_callback *callback; | |
760 | void *u; | |
761 | }; | |
762 | ||
768d7355 | 763 | /** @brief Called when a listenign socket is readable */ |
460b9539 | 764 | static int listen_callback(ev_source *ev, int fd, void *u) { |
765 | const struct listen_state *l = u; | |
766 | int newfd; | |
767 | union { | |
768 | struct sockaddr_in in; | |
769 | #if HAVE_STRUCT_SOCKADDR_IN6 | |
770 | struct sockaddr_in6 in6; | |
771 | #endif | |
772 | struct sockaddr_un un; | |
773 | struct sockaddr sa; | |
774 | } addr; | |
775 | socklen_t addrlen; | |
776 | int ret; | |
777 | ||
778 | D(("callback for listener fd %d", fd)); | |
779 | while((addrlen = sizeof addr), | |
780 | (newfd = accept(fd, &addr.sa, &addrlen)) >= 0) { | |
781 | if((ret = l->callback(ev, newfd, &addr.sa, addrlen, l->u))) | |
782 | return ret; | |
783 | } | |
784 | switch(errno) { | |
785 | case EINTR: | |
786 | case EAGAIN: | |
787 | break; | |
788 | #ifdef ECONNABORTED | |
789 | case ECONNABORTED: | |
790 | error(errno, "error calling accept"); | |
791 | break; | |
792 | #endif | |
793 | #ifdef EPROTO | |
794 | case EPROTO: | |
795 | /* XXX on some systems EPROTO should be fatal, but we don't know if | |
796 | * we're running on one of them */ | |
797 | error(errno, "error calling accept"); | |
798 | break; | |
799 | #endif | |
800 | default: | |
801 | fatal(errno, "error calling accept"); | |
802 | break; | |
803 | } | |
804 | if(errno != EINTR && errno != EAGAIN) | |
805 | error(errno, "error calling accept"); | |
806 | return 0; | |
807 | } | |
808 | ||
768d7355 RK |
809 | /** @brief Listen on a socket for inbound stream connections |
810 | * @param ev Event source | |
811 | * @param fd File descriptor of socket | |
812 | * @param callback Called when a new connection arrives | |
813 | * @param u Passed to @p callback | |
814 | * @param what Text description of socket | |
815 | * @return 0 on success, non-0 on error | |
816 | */ | |
460b9539 | 817 | int ev_listen(ev_source *ev, |
818 | int fd, | |
819 | ev_listen_callback *callback, | |
e8c92ba7 RK |
820 | void *u, |
821 | const char *what) { | |
460b9539 | 822 | struct listen_state *l = xmalloc(sizeof *l); |
823 | ||
824 | D(("registering listener fd %d callback %p %p", fd, (void *)callback, u)); | |
825 | l->callback = callback; | |
826 | l->u = u; | |
e8c92ba7 | 827 | return ev_fd(ev, ev_read, fd, listen_callback, l, what); |
460b9539 | 828 | } |
829 | ||
768d7355 RK |
830 | /** @brief Stop listening on a socket |
831 | * @param ev Event loop | |
832 | * @param fd File descriptor of socket | |
833 | * @return 0 on success, non-0 on error | |
834 | */ | |
460b9539 | 835 | int ev_listen_cancel(ev_source *ev, int fd) { |
836 | D(("cancelling listener fd %d", fd)); | |
837 | return ev_fd_cancel(ev, ev_read, fd); | |
838 | } | |
839 | ||
840 | /* buffer *********************************************************************/ | |
841 | ||
768d7355 | 842 | /** @brief Buffer structure */ |
460b9539 | 843 | struct buffer { |
844 | char *base, *start, *end, *top; | |
845 | }; | |
846 | ||
768d7355 | 847 | /* @brief Make sure there is @p bytes available at @c b->end */ |
460b9539 | 848 | static void buffer_space(struct buffer *b, size_t bytes) { |
849 | D(("buffer_space %p %p %p %p want %lu", | |
850 | (void *)b->base, (void *)b->start, (void *)b->end, (void *)b->top, | |
851 | (unsigned long)bytes)); | |
852 | if(b->start == b->end) | |
853 | b->start = b->end = b->base; | |
854 | if((size_t)(b->top - b->end) < bytes) { | |
855 | if((size_t)((b->top - b->end) + (b->start - b->base)) < bytes) { | |
856 | size_t newspace = b->end - b->start + bytes, n; | |
857 | char *newbase; | |
858 | ||
859 | for(n = 16; n < newspace; n *= 2) | |
860 | ; | |
861 | newbase = xmalloc_noptr(n); | |
862 | memcpy(newbase, b->start, b->end - b->start); | |
863 | b->base = newbase; | |
864 | b->end = newbase + (b->end - b->start); | |
865 | b->top = newbase + n; | |
866 | b->start = newbase; /* must be last */ | |
867 | } else { | |
868 | memmove(b->base, b->start, b->end - b->start); | |
869 | b->end = b->base + (b->end - b->start); | |
870 | b->start = b->base; | |
871 | } | |
872 | } | |
873 | D(("result %p %p %p %p", | |
874 | (void *)b->base, (void *)b->start, (void *)b->end, (void *)b->top)); | |
875 | } | |
876 | ||
75d64210 | 877 | /* readers and writers *******************************************************/ |
460b9539 | 878 | |
768d7355 | 879 | /** @brief State structure for a buffered writer */ |
460b9539 | 880 | struct ev_writer { |
75d64210 | 881 | /** @brief Sink used for writing to the buffer */ |
460b9539 | 882 | struct sink s; |
75d64210 RK |
883 | |
884 | /** @brief Output buffer */ | |
460b9539 | 885 | struct buffer b; |
75d64210 RK |
886 | |
887 | /** @brief File descriptor to write to */ | |
460b9539 | 888 | int fd; |
75d64210 RK |
889 | |
890 | /** @brief Set if there'll be no more output */ | |
460b9539 | 891 | int eof; |
75d64210 RK |
892 | |
893 | /** @brief Error/termination callback */ | |
460b9539 | 894 | ev_error_callback *callback; |
75d64210 RK |
895 | |
896 | /** @brief Passed to @p callback */ | |
460b9539 | 897 | void *u; |
75d64210 RK |
898 | |
899 | /** @brief Parent event source */ | |
460b9539 | 900 | ev_source *ev; |
cb9a695c RK |
901 | |
902 | /** @brief Maximum amount of time between succesful writes, 0 = don't care */ | |
903 | int timebound; | |
904 | /** @brief Maximum amount of data to buffer, 0 = don't care */ | |
905 | int spacebound; | |
75d64210 RK |
906 | /** @brief Error code to pass to @p callback (see writer_shutdown()) */ |
907 | int error; | |
cb9a695c RK |
908 | /** @brief Timeout handle for @p timebound (or 0) */ |
909 | ev_timeout_handle timeout; | |
910 | ||
75d64210 | 911 | /** @brief Description of this writer */ |
cb9a695c | 912 | const char *what; |
75d64210 RK |
913 | |
914 | /** @brief Tied reader or 0 */ | |
915 | ev_reader *reader; | |
d742bb47 RK |
916 | |
917 | /** @brief Set when abandoned */ | |
918 | int abandoned; | |
460b9539 | 919 | }; |
920 | ||
75d64210 RK |
921 | /** @brief State structure for a buffered reader */ |
922 | struct ev_reader { | |
923 | /** @brief Input buffer */ | |
924 | struct buffer b; | |
925 | /** @brief File descriptor read from */ | |
926 | int fd; | |
927 | /** @brief Called when new data is available */ | |
928 | ev_reader_callback *callback; | |
929 | /** @brief Called on error and shutdown */ | |
930 | ev_error_callback *error_callback; | |
931 | /** @brief Passed to @p callback and @p error_callback */ | |
932 | void *u; | |
933 | /** @brief Parent event loop */ | |
934 | ev_source *ev; | |
935 | /** @brief Set when EOF is detected */ | |
936 | int eof; | |
937 | /** @brief Error code to pass to error callback */ | |
938 | int error; | |
939 | /** @brief Tied writer or NULL */ | |
940 | ev_writer *writer; | |
941 | }; | |
942 | ||
943 | /* buffered writer ************************************************************/ | |
944 | ||
945 | /** @brief Shut down the writer | |
946 | * | |
947 | * This is called to shut down a writer. The error callback is not called | |
948 | * through any other path. Also we do not cancel @p fd from anywhere else, | |
949 | * though we might disable it. | |
950 | * | |
951 | * It has the signature of a timeout callback so that it can be called from a | |
952 | * time=0 timeout. | |
cb9a695c RK |
953 | * |
954 | * Calls @p callback with @p w->syntherr as the error code (which might be 0). | |
955 | */ | |
956 | static int writer_shutdown(ev_source *ev, | |
957 | const attribute((unused)) struct timeval *now, | |
958 | void *u) { | |
959 | ev_writer *w = u; | |
960 | ||
e4a9c7c5 | 961 | if(w->fd == -1) |
75d64210 | 962 | return 0; /* already shut down */ |
0fa83caa | 963 | D(("writer_shutdown fd=%d error=%d", w->fd, w->error)); |
cb9a695c | 964 | ev_timeout_cancel(ev, w->timeout); |
75d64210 | 965 | ev_fd_cancel(ev, ev_write, w->fd); |
cb9a695c | 966 | w->timeout = 0; |
75d64210 | 967 | if(w->reader) { |
0fa83caa | 968 | D(("found a tied reader")); |
75d64210 RK |
969 | /* If there is a reader still around we just untie it */ |
970 | w->reader->writer = 0; | |
971 | shutdown(w->fd, SHUT_WR); /* there'll be no more writes */ | |
972 | } else { | |
0fa83caa | 973 | D(("no tied reader")); |
75d64210 RK |
974 | /* There's no reader so we are free to close the FD */ |
975 | xclose(w->fd); | |
976 | } | |
e4a9c7c5 | 977 | w->fd = -1; |
75d64210 | 978 | return w->callback(ev, w->error, w->u); |
cb9a695c RK |
979 | } |
980 | ||
981 | /** @brief Called when a writer's @p timebound expires */ | |
982 | static int writer_timebound_exceeded(ev_source *ev, | |
75d64210 | 983 | const struct timeval *now, |
cb9a695c RK |
984 | void *u) { |
985 | ev_writer *const w = u; | |
986 | ||
d742bb47 RK |
987 | if(!w->abandoned) { |
988 | w->abandoned = 1; | |
989 | error(0, "abandoning writer '%s' because no writes within %ds", | |
990 | w->what, w->timebound); | |
991 | w->error = ETIMEDOUT; | |
992 | } | |
75d64210 | 993 | return writer_shutdown(ev, now, u); |
cb9a695c RK |
994 | } |
995 | ||
996 | /** @brief Set the time bound callback (if not set already) */ | |
997 | static void writer_set_timebound(ev_writer *w) { | |
998 | if(w->timebound && !w->timeout) { | |
999 | struct timeval when; | |
1000 | ev_source *const ev = w->ev; | |
1001 | ||
1002 | xgettimeofday(&when, 0); | |
1003 | when.tv_sec += w->timebound; | |
1004 | ev_timeout(ev, &w->timeout, &when, writer_timebound_exceeded, w); | |
1005 | } | |
1006 | } | |
1007 | ||
768d7355 | 1008 | /** @brief Called when a writer's file descriptor is writable */ |
460b9539 | 1009 | static int writer_callback(ev_source *ev, int fd, void *u) { |
cb9a695c | 1010 | ev_writer *const w = u; |
460b9539 | 1011 | int n; |
1012 | ||
1013 | n = write(fd, w->b.start, w->b.end - w->b.start); | |
1014 | D(("callback for writer fd %d, %ld bytes, n=%d, errno=%d", | |
1015 | fd, (long)(w->b.end - w->b.start), n, errno)); | |
1016 | if(n >= 0) { | |
75d64210 | 1017 | /* Consume bytes from the buffer */ |
460b9539 | 1018 | w->b.start += n; |
75d64210 | 1019 | /* Suppress any outstanding timeout */ |
cb9a695c RK |
1020 | ev_timeout_cancel(ev, w->timeout); |
1021 | w->timeout = 0; | |
460b9539 | 1022 | if(w->b.start == w->b.end) { |
75d64210 | 1023 | /* The buffer is empty */ |
460b9539 | 1024 | if(w->eof) { |
75d64210 RK |
1025 | /* We're done, we can shut down this writer */ |
1026 | w->error = 0; | |
1027 | return writer_shutdown(ev, 0, w); | |
460b9539 | 1028 | } else |
75d64210 RK |
1029 | /* There might be more to come but we don't need writer_callback() to |
1030 | * be called for the time being */ | |
460b9539 | 1031 | ev_fd_disable(ev, ev_write, fd); |
cb9a695c | 1032 | } else |
75d64210 RK |
1033 | /* The buffer isn't empty, set a timeout so we give up if we don't manage |
1034 | * to write some more within a reasonable time */ | |
cb9a695c | 1035 | writer_set_timebound(w); |
460b9539 | 1036 | } else { |
1037 | switch(errno) { | |
1038 | case EINTR: | |
1039 | case EAGAIN: | |
1040 | break; | |
1041 | default: | |
75d64210 RK |
1042 | w->error = errno; |
1043 | return writer_shutdown(ev, 0, w); | |
460b9539 | 1044 | } |
1045 | } | |
1046 | return 0; | |
1047 | } | |
1048 | ||
768d7355 RK |
1049 | /** @brief Write bytes to a writer's buffer |
1050 | * | |
1051 | * This is the sink write callback. | |
1052 | * | |
1053 | * Calls ev_fd_enable() if necessary (i.e. if the buffer was empty but | |
1054 | * now is not). | |
1055 | */ | |
460b9539 | 1056 | static int ev_writer_write(struct sink *sk, const void *s, int n) { |
1057 | ev_writer *w = (ev_writer *)sk; | |
cb9a695c RK |
1058 | |
1059 | if(!n) | |
1060 | return 0; /* avoid silliness */ | |
38b8221f RK |
1061 | if(w->fd == -1) |
1062 | error(0, "ev_writer_write on %s after shutdown", w->what); | |
75d64210 RK |
1063 | if(w->spacebound && w->b.end - w->b.start + n > w->spacebound) { |
1064 | /* The new buffer contents will exceed the space bound. We assume that the | |
cb9a695c RK |
1065 | * remote client has gone away and TCP hasn't noticed yet, or that it's got |
1066 | * hopelessly stuck. */ | |
d742bb47 RK |
1067 | if(!w->abandoned) { |
1068 | w->abandoned = 1; | |
1069 | error(0, "abandoning writer '%s' because buffer has reached %td bytes", | |
1070 | w->what, w->b.end - w->b.start); | |
1071 | ev_fd_disable(w->ev, ev_write, w->fd); | |
1072 | w->error = EPIPE; | |
1073 | return ev_timeout(w->ev, 0, 0, writer_shutdown, w); | |
1074 | } else | |
1075 | return 0; | |
cb9a695c | 1076 | } |
75d64210 RK |
1077 | /* Make sure there is space */ |
1078 | buffer_space(&w->b, n); | |
1079 | /* If the buffer was formerly empty then we'll need to re-enable the FD */ | |
1080 | if(w->b.start == w->b.end) | |
1081 | ev_fd_enable(w->ev, ev_write, w->fd); | |
1082 | memcpy(w->b.end, s, n); | |
1083 | w->b.end += n; | |
1084 | /* Arrange a timeout if there wasn't one set already */ | |
cb9a695c | 1085 | writer_set_timebound(w); |
460b9539 | 1086 | return 0; |
1087 | } | |
1088 | ||
768d7355 RK |
1089 | /** @brief Create a new buffered writer |
1090 | * @param ev Event loop | |
1091 | * @param fd File descriptor to write to | |
1092 | * @param callback Called if an error occurs and when finished | |
1093 | * @param u Passed to @p callback | |
1094 | * @param what Text description | |
1095 | * @return New writer or @c NULL | |
75d64210 RK |
1096 | * |
1097 | * Writers own their file descriptor and close it when they have finished with | |
1098 | * it. | |
1099 | * | |
1100 | * If you pass the same fd to a reader and writer, you must tie them together | |
1101 | * with ev_tie(). | |
768d7355 | 1102 | */ |
460b9539 | 1103 | ev_writer *ev_writer_new(ev_source *ev, |
1104 | int fd, | |
1105 | ev_error_callback *callback, | |
e8c92ba7 RK |
1106 | void *u, |
1107 | const char *what) { | |
460b9539 | 1108 | ev_writer *w = xmalloc(sizeof *w); |
1109 | ||
1110 | D(("registering writer fd %d callback %p %p", fd, (void *)callback, u)); | |
1111 | w->s.write = ev_writer_write; | |
1112 | w->fd = fd; | |
1113 | w->callback = callback; | |
1114 | w->u = u; | |
1115 | w->ev = ev; | |
cb9a695c RK |
1116 | w->timebound = 10 * 60; |
1117 | w->spacebound = 512 * 1024; | |
1118 | w->what = what; | |
e8c92ba7 | 1119 | if(ev_fd(ev, ev_write, fd, writer_callback, w, what)) |
460b9539 | 1120 | return 0; |
75d64210 | 1121 | /* Buffer is initially empty so we don't want a callback */ |
460b9539 | 1122 | ev_fd_disable(ev, ev_write, fd); |
1123 | return w; | |
1124 | } | |
1125 | ||
cb9a695c RK |
1126 | /** @brief Get/set the time bound |
1127 | * @param w Writer | |
1128 | * @param new_time_bound New bound or -1 for no change | |
1129 | * @return Latest time bound | |
1130 | * | |
1131 | * If @p new_time_bound is negative then the current time bound is returned. | |
1132 | * Otherwise it is set and the new value returned. | |
1133 | * | |
1134 | * The time bound is the number of seconds allowed between writes. If it takes | |
1135 | * longer than this to flush a buffer then the peer will be assumed to be dead | |
1136 | * and an error will be synthesized. 0 means "don't care". The default time | |
1137 | * bound is 10 minutes. | |
1138 | * | |
1139 | * Note that this value does not take into account kernel buffering and | |
1140 | * timeouts. | |
1141 | */ | |
1142 | int ev_writer_time_bound(ev_writer *w, | |
1143 | int new_time_bound) { | |
1144 | if(new_time_bound >= 0) | |
1145 | w->timebound = new_time_bound; | |
1146 | return w->timebound; | |
1147 | } | |
1148 | ||
1149 | /** @brief Get/set the space bound | |
1150 | * @param w Writer | |
1151 | * @param new_space_bound New bound or -1 for no change | |
1152 | * @return Latest space bound | |
1153 | * | |
1154 | * If @p new_space_bound is negative then the current space bound is returned. | |
1155 | * Otherwise it is set and the new value returned. | |
1156 | * | |
1157 | * The space bound is the number of bytes allowed between in the buffer. If | |
1158 | * the buffer exceeds this size an error will be synthesized. 0 means "don't | |
1159 | * care". The default space bound is 512Kbyte. | |
1160 | * | |
1161 | * Note that this value does not take into account kernel buffering. | |
1162 | */ | |
1163 | int ev_writer_space_bound(ev_writer *w, | |
1164 | int new_space_bound) { | |
1165 | if(new_space_bound >= 0) | |
1166 | w->spacebound = new_space_bound; | |
1167 | return w->spacebound; | |
1168 | } | |
1169 | ||
768d7355 RK |
1170 | /** @brief Return the sink associated with a writer |
1171 | * @param w Writer | |
1172 | * @return Pointer to sink | |
1173 | * | |
1174 | * Writing to the sink will arrange for those bytes to be written to the file | |
1175 | * descriptor as and when it is writable. | |
1176 | */ | |
460b9539 | 1177 | struct sink *ev_writer_sink(ev_writer *w) { |
f6033c46 RK |
1178 | if(!w) |
1179 | fatal(0, "ev_write_sink called with null writer"); | |
460b9539 | 1180 | return &w->s; |
1181 | } | |
1182 | ||
768d7355 RK |
1183 | /** @brief Close a writer |
1184 | * @param w Writer to close | |
1185 | * @return 0 on success, non-0 on error | |
1186 | * | |
1187 | * Close a writer. No more bytes should be written to its sink. | |
1188 | * | |
1189 | * When the last byte has been written the callback will be called with an | |
1190 | * error code of 0. It is guaranteed that this will NOT happen before | |
1191 | * ev_writer_close() returns (although the file descriptor for the writer might | |
1192 | * be cancelled by the time it returns). | |
1193 | */ | |
460b9539 | 1194 | int ev_writer_close(ev_writer *w) { |
1195 | D(("close writer fd %d", w->fd)); | |
75d64210 RK |
1196 | if(w->eof) |
1197 | return 0; /* already closed */ | |
460b9539 | 1198 | w->eof = 1; |
1199 | if(w->b.start == w->b.end) { | |
75d64210 RK |
1200 | /* We're already finished */ |
1201 | w->error = 0; /* no error */ | |
460b9539 | 1202 | return ev_timeout(w->ev, 0, 0, writer_shutdown, w); |
1203 | } | |
1204 | return 0; | |
1205 | } | |
1206 | ||
768d7355 RK |
1207 | /** @brief Attempt to flush a writer |
1208 | * @param w Writer to flush | |
1209 | * @return 0 on success, non-0 on error | |
1210 | * | |
1211 | * Does a speculative write of any buffered data. Does not block if it cannot | |
1212 | * be written. | |
1213 | */ | |
460b9539 | 1214 | int ev_writer_flush(ev_writer *w) { |
1215 | return writer_callback(w->ev, w->fd, w); | |
1216 | } | |
1217 | ||
1218 | /* buffered reader ************************************************************/ | |
1219 | ||
49a773eb | 1220 | /** @brief Shut down a reader |
75d64210 RK |
1221 | * |
1222 | * This is the only path through which we cancel and close the file descriptor. | |
1223 | * As with the writer case it is given timeout signature to allow it be | |
1224 | * deferred to the next iteration of the event loop. | |
1225 | * | |
1226 | * We only call @p error_callback if @p error is nonzero (unlike the writer | |
1227 | * case). | |
1228 | */ | |
1229 | static int reader_shutdown(ev_source *ev, | |
1230 | const attribute((unused)) struct timeval *now, | |
1231 | void *u) { | |
1232 | ev_reader *const r = u; | |
1233 | ||
1234 | if(r->fd == -1) | |
1235 | return 0; /* already shut down */ | |
0fa83caa | 1236 | D(("reader_shutdown fd=%d", r->fd)); |
75d64210 RK |
1237 | ev_fd_cancel(ev, ev_read, r->fd); |
1238 | r->eof = 1; | |
1239 | if(r->writer) { | |
0fa83caa | 1240 | D(("found a tied writer")); |
75d64210 RK |
1241 | /* If there is a writer still around we just untie it */ |
1242 | r->writer->reader = 0; | |
1243 | shutdown(r->fd, SHUT_RD); /* there'll be no more reads */ | |
1244 | } else { | |
0fa83caa | 1245 | D(("no tied writer found")); |
75d64210 RK |
1246 | /* There's no writer so we are free to close the FD */ |
1247 | xclose(r->fd); | |
1248 | } | |
1249 | r->fd = -1; | |
1250 | if(r->error) | |
1251 | return r->error_callback(ev, r->error, r->u); | |
1252 | else | |
1253 | return 0; | |
1254 | } | |
460b9539 | 1255 | |
768d7355 | 1256 | /** @brief Called when a reader's @p fd is readable */ |
460b9539 | 1257 | static int reader_callback(ev_source *ev, int fd, void *u) { |
1258 | ev_reader *r = u; | |
1259 | int n; | |
1260 | ||
1261 | buffer_space(&r->b, 1); | |
1262 | n = read(fd, r->b.end, r->b.top - r->b.end); | |
1263 | D(("read fd %d buffer %d returned %d errno %d", | |
1264 | fd, (int)(r->b.top - r->b.end), n, errno)); | |
1265 | if(n > 0) { | |
1266 | r->b.end += n; | |
75d64210 | 1267 | return r->callback(ev, r, r->b.start, r->b.end - r->b.start, 0, r->u); |
460b9539 | 1268 | } else if(n == 0) { |
75d64210 RK |
1269 | /* No more read callbacks needed */ |
1270 | ev_fd_disable(r->ev, ev_read, r->fd); | |
1271 | ev_timeout(r->ev, 0, 0, reader_shutdown, r); | |
1272 | /* Pass the remaining data and an eof indicator to the user */ | |
1273 | return r->callback(ev, r, r->b.start, r->b.end - r->b.start, 1, r->u); | |
460b9539 | 1274 | } else { |
1275 | switch(errno) { | |
1276 | case EINTR: | |
1277 | case EAGAIN: | |
1278 | break; | |
1279 | default: | |
75d64210 RK |
1280 | /* Fatal error, kill the reader now */ |
1281 | r->error = errno; | |
1282 | return reader_shutdown(ev, 0, r); | |
460b9539 | 1283 | } |
1284 | } | |
1285 | return 0; | |
1286 | } | |
1287 | ||
768d7355 RK |
1288 | /** @brief Create a new buffered reader |
1289 | * @param ev Event loop | |
1290 | * @param fd File descriptor to read from | |
1291 | * @param callback Called when new data is available | |
1292 | * @param error_callback Called if an error occurs | |
1293 | * @param u Passed to callbacks | |
1294 | * @param what Text description | |
1295 | * @return New reader or @c NULL | |
75d64210 RK |
1296 | * |
1297 | * Readers own their fd and close it when they are finished with it. | |
1298 | * | |
1299 | * If you pass the same fd to a reader and writer, you must tie them together | |
1300 | * with ev_tie(). | |
768d7355 | 1301 | */ |
460b9539 | 1302 | ev_reader *ev_reader_new(ev_source *ev, |
1303 | int fd, | |
1304 | ev_reader_callback *callback, | |
1305 | ev_error_callback *error_callback, | |
e8c92ba7 RK |
1306 | void *u, |
1307 | const char *what) { | |
460b9539 | 1308 | ev_reader *r = xmalloc(sizeof *r); |
1309 | ||
1310 | D(("registering reader fd %d callback %p %p %p", | |
1311 | fd, (void *)callback, (void *)error_callback, u)); | |
1312 | r->fd = fd; | |
1313 | r->callback = callback; | |
1314 | r->error_callback = error_callback; | |
1315 | r->u = u; | |
1316 | r->ev = ev; | |
e8c92ba7 | 1317 | if(ev_fd(ev, ev_read, fd, reader_callback, r, what)) |
460b9539 | 1318 | return 0; |
1319 | return r; | |
1320 | } | |
1321 | ||
1322 | void ev_reader_buffer(ev_reader *r, size_t nbytes) { | |
1323 | buffer_space(&r->b, nbytes - (r->b.end - r->b.start)); | |
1324 | } | |
1325 | ||
768d7355 RK |
1326 | /** @brief Consume @p n bytes from the reader's buffer |
1327 | * @param r Reader | |
1328 | * @param n Number of bytes to consume | |
1329 | * | |
1330 | * Tells the reader than the next @p n bytes have been dealt with and can now | |
1331 | * be discarded. | |
1332 | */ | |
460b9539 | 1333 | void ev_reader_consume(ev_reader *r, size_t n) { |
1334 | r->b.start += n; | |
1335 | } | |
1336 | ||
768d7355 RK |
1337 | /** @brief Cancel a reader |
1338 | * @param r Reader | |
1339 | * @return 0 on success, non-0 on error | |
75d64210 RK |
1340 | * |
1341 | * No further callbacks will be made, and the FD will be closed (in a later | |
1342 | * iteration of the event loop). | |
768d7355 | 1343 | */ |
460b9539 | 1344 | int ev_reader_cancel(ev_reader *r) { |
1345 | D(("cancel reader fd %d", r->fd)); | |
75d64210 RK |
1346 | if(r->fd == -1) |
1347 | return 0; /* already thoroughly cancelled */ | |
1348 | ev_fd_disable(r->ev, ev_read, r->fd); | |
1349 | return ev_timeout(r->ev, 0, 0, reader_shutdown, r); | |
460b9539 | 1350 | } |
1351 | ||
768d7355 RK |
1352 | /** @brief Temporarily disable a reader |
1353 | * @param r Reader | |
1354 | * @return 0 on success, non-0 on error | |
1355 | * | |
1356 | * No further callbacks for this reader will be made. Re-enable with | |
1357 | * ev_reader_enable(). | |
1358 | */ | |
460b9539 | 1359 | int ev_reader_disable(ev_reader *r) { |
1360 | D(("disable reader fd %d", r->fd)); | |
75d64210 | 1361 | return ev_fd_disable(r->ev, ev_read, r->fd); |
460b9539 | 1362 | } |
1363 | ||
768d7355 | 1364 | /** @brief Called from ev_run() for ev_reader_incomplete() */ |
460b9539 | 1365 | static int reader_continuation(ev_source attribute((unused)) *ev, |
1366 | const attribute((unused)) struct timeval *now, | |
1367 | void *u) { | |
1368 | ev_reader *r = u; | |
1369 | ||
1370 | D(("reader continuation callback fd %d", r->fd)); | |
75d64210 RK |
1371 | /* If not at EOF turn the FD back on */ |
1372 | if(!r->eof) | |
1373 | if(ev_fd_enable(r->ev, ev_read, r->fd)) | |
1374 | return -1; | |
1375 | /* We're already in a timeout callback so there's no reason we can't call the | |
1376 | * user callback directly (compare ev_reader_enable()). */ | |
1377 | return r->callback(ev, r, r->b.start, r->b.end - r->b.start, r->eof, r->u); | |
460b9539 | 1378 | } |
1379 | ||
768d7355 RK |
1380 | /** @brief Arrange another callback |
1381 | * @param r reader | |
1382 | * @return 0 on success, non-0 on error | |
1383 | * | |
1384 | * Indicates that the reader can process more input but would like to yield to | |
1385 | * other clients of the event loop. Input will be disabled but it will be | |
1386 | * re-enabled on the next iteration of the event loop and the read callback | |
1387 | * will be called again (even if no further bytes are available). | |
1388 | */ | |
460b9539 | 1389 | int ev_reader_incomplete(ev_reader *r) { |
1390 | if(ev_fd_disable(r->ev, ev_read, r->fd)) return -1; | |
1391 | return ev_timeout(r->ev, 0, 0, reader_continuation, r); | |
1392 | } | |
1393 | ||
1394 | static int reader_enabled(ev_source *ev, | |
1395 | const attribute((unused)) struct timeval *now, | |
1396 | void *u) { | |
1397 | ev_reader *r = u; | |
1398 | ||
1399 | D(("reader enabled callback fd %d", r->fd)); | |
75d64210 | 1400 | return r->callback(ev, r, r->b.start, r->b.end - r->b.start, r->eof, r->u); |
460b9539 | 1401 | } |
1402 | ||
768d7355 RK |
1403 | /** @brief Re-enable reading |
1404 | * @param r reader | |
1405 | * @return 0 on success, non-0 on error | |
1406 | * | |
1407 | * If there is unconsumed data then you get a callback next time round the | |
1408 | * event loop even if nothing new has been read. | |
1409 | * | |
1410 | * The idea is in your read callback you come across a line (or whatever) that | |
1411 | * can't be processed immediately. So you set up processing and disable | |
1412 | * reading with ev_reader_disable(). Later when you finish processing you | |
1413 | * re-enable. You'll automatically get another callback directly from the | |
1414 | * event loop (i.e. not from inside ev_reader_enable()) so you can handle the | |
1415 | * next line (or whatever) if the whole thing has in fact already arrived. | |
75d64210 RK |
1416 | * |
1417 | * The difference between this process and calling ev_reader_incomplete() is | |
1418 | * ev_reader_incomplete() deals with the case where you can process now but | |
1419 | * would rather yield to other clients of the event loop, while using | |
1420 | * ev_reader_disable() and ev_reader_enable() deals with the case where you | |
1421 | * cannot process input yet because some other process is actually not | |
1422 | * complete. | |
768d7355 | 1423 | */ |
460b9539 | 1424 | int ev_reader_enable(ev_reader *r) { |
1425 | D(("enable reader fd %d", r->fd)); | |
75d64210 RK |
1426 | |
1427 | /* First if we're not at EOF then we re-enable reading */ | |
1428 | if(!r->eof) | |
1429 | if(ev_fd_enable(r->ev, ev_read, r->fd)) | |
1430 | return -1; | |
1431 | /* Arrange another callback next time round the event loop */ | |
1432 | return ev_timeout(r->ev, 0, 0, reader_enabled, r); | |
1433 | } | |
1434 | ||
1435 | /** @brief Tie a reader and a writer together | |
1436 | * @param r Reader | |
1437 | * @param w Writer | |
1438 | * @return 0 on success, non-0 on error | |
1439 | * | |
1440 | * This function must be called if @p r and @p w share a file descritptor. | |
1441 | */ | |
1442 | int ev_tie(ev_reader *r, ev_writer *w) { | |
1443 | assert(r->writer == 0); | |
1444 | assert(w->reader == 0); | |
1445 | r->writer = w; | |
1446 | w->reader = r; | |
1447 | return 0; | |
460b9539 | 1448 | } |
1449 | ||
1450 | /* | |
1451 | Local Variables: | |
1452 | c-basic-offset:2 | |
1453 | comment-column:40 | |
1454 | fill-column:79 | |
1455 | End: | |
1456 | */ |