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