chiark / gitweb /
DisOrder's event loop now stores its timeouts in heap sorted by
[disorder] / lib / event.c
CommitLineData
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
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"
3af7813d
RK
50#include "timeval.h"
51#include "heap.h"
460b9539 52
768d7355 53/** @brief A timeout */
460b9539 54struct timeout {
55 struct timeout *next;
56 struct timeval when;
57 ev_timeout_callback *callback;
58 void *u;
3af7813d 59 int active;
460b9539 60};
61
3af7813d
RK
62/** @brief Comparison function for timeouts */
63static int timeout_lt(const struct timeout *a,
64 const struct timeout *b) {
65 return tvlt(&a->when, &b->when);
66}
67
68HEAP_TYPE(timeout_heap, struct timeout *, timeout_lt);
69HEAP_DEFINE(timeout_heap, struct timeout *, timeout_lt);
70
768d7355 71/** @brief A file descriptor in one mode */
460b9539 72struct fd {
73 int fd;
74 ev_fd_callback *callback;
75 void *u;
e8c92ba7 76 const char *what;
460b9539 77};
78
768d7355 79/** @brief All the file descriptors in a given mode */
460b9539 80struct fdmode {
768d7355 81 /** @brief Mask of active file descriptors passed to @c select() */
460b9539 82 fd_set enabled;
768d7355
RK
83
84 /** @brief File descriptor mask returned from @c select() */
460b9539 85 fd_set tripped;
768d7355
RK
86
87 /** @brief Number of file descriptors in @p fds */
88 int nfds;
89
90 /** @brief Number of slots in @p fds */
91 int fdslots;
92
93 /** @brief Array of all active file descriptors */
460b9539 94 struct fd *fds;
768d7355
RK
95
96 /** @brief Highest-numbered file descriptor or 0 */
460b9539 97 int maxfd;
98};
99
768d7355 100/** @brief A signal handler */
460b9539 101struct signal {
102 struct sigaction oldsa;
103 ev_signal_callback *callback;
104 void *u;
105};
106
768d7355 107/** @brief A child process */
460b9539 108struct child {
109 pid_t pid;
110 int options;
111 ev_child_callback *callback;
112 void *u;
113};
114
768d7355 115/** @brief An event loop */
460b9539 116struct ev_source {
768d7355 117 /** @brief File descriptors, per mode */
460b9539 118 struct fdmode mode[ev_nmodes];
768d7355 119
3af7813d
RK
120 /** @brief Heap of timeouts */
121 struct timeout_heap timeouts[1];
768d7355
RK
122
123 /** @brief Array of handled signals */
460b9539 124 struct signal signals[NSIG];
768d7355
RK
125
126 /** @brief Mask of handled signals */
460b9539 127 sigset_t sigmask;
768d7355
RK
128
129 /** @brief Escape early from handling of @c select() results
130 *
131 * This is set if any of the file descriptor arrays are invalidated, since
132 * it's then not safe for processing of them to continue.
133 */
460b9539 134 int escape;
768d7355
RK
135
136 /** @brief Signal handling pipe
137 *
138 * The signal handle writes signal numbers down this pipe.
139 */
460b9539 140 int sigpipe[2];
768d7355
RK
141
142 /** @brief Number of child processes in @p children */
143 int nchildren;
144
145 /** @brief Number of slots in @p children */
146 int nchildslots;
147
148 /** @brief Array of child processes */
460b9539 149 struct child *children;
150};
151
768d7355 152/** @brief Names of file descriptor modes */
460b9539 153static const char *modenames[] = { "read", "write", "except" };
154
155/* utilities ******************************************************************/
156
460b9539 157/* creation *******************************************************************/
158
768d7355 159/** @brief Create a new event loop */
460b9539 160ev_source *ev_new(void) {
161 ev_source *ev = xmalloc(sizeof *ev);
162 int n;
163
164 memset(ev, 0, sizeof *ev);
165 for(n = 0; n < ev_nmodes; ++n)
166 FD_ZERO(&ev->mode[n].enabled);
167 ev->sigpipe[0] = ev->sigpipe[1] = -1;
168 sigemptyset(&ev->sigmask);
3af7813d 169 timeout_heap_init(ev->timeouts);
460b9539 170 return ev;
171}
172
173/* event loop *****************************************************************/
174
768d7355
RK
175/** @brief Run the event loop
176 * @return -1 on error, non-0 if any callback returned non-0
177 */
460b9539 178int ev_run(ev_source *ev) {
179 for(;;) {
180 struct timeval now;
181 struct timeval delta;
182 int n, mode;
183 int ret;
184 int maxfd;
3af7813d 185 struct timeout *timeouts, *t, **tt;
e8c92ba7 186 struct stat sb;
460b9539 187
188 xgettimeofday(&now, 0);
189 /* Handle timeouts. We don't want to handle any timeouts that are added
190 * while we're handling them (otherwise we'd have to break out of infinite
191 * loops, preferrably without starving better-behaved subsystems). Hence
192 * the slightly complicated two-phase approach here. */
3af7813d
RK
193 /* First we read those timeouts that have triggered out of the heap. We
194 * keep them in the same order they came out of the heap in. */
195 tt = &timeouts;
196 while(timeout_heap_count(ev->timeouts)
197 && tvle(&timeout_heap_first(ev->timeouts)->when, &now)) {
198 /* This timeout has reached its trigger time; provided it has not been
199 * cancelled we add it to the timeouts list. */
200 t = timeout_heap_remove(ev->timeouts);
201 if(t->active) {
202 *tt = t;
203 tt = &t->next;
204 }
205 }
206 *tt = 0;
207 /* Now we can run the callbacks for those timeouts. They might add further
208 * timeouts that are already in the past but they won't trigger until the
209 * next time round the event loop. */
210 for(t = timeouts; t; t = t->next) {
460b9539 211 D(("calling timeout for %ld.%ld callback %p %p",
212 (long)t->when.tv_sec, (long)t->when.tv_usec,
213 (void *)t->callback, t->u));
214 ret = t->callback(ev, &now, t->u);
215 if(ret)
216 return ret;
217 }
460b9539 218 maxfd = 0;
219 for(mode = 0; mode < ev_nmodes; ++mode) {
220 ev->mode[mode].tripped = ev->mode[mode].enabled;
221 if(ev->mode[mode].maxfd > maxfd)
222 maxfd = ev->mode[mode].maxfd;
223 }
224 xsigprocmask(SIG_UNBLOCK, &ev->sigmask, 0);
225 do {
3af7813d
RK
226 if(timeout_heap_count(ev->timeouts)) {
227 t = timeout_heap_first(ev->timeouts);
460b9539 228 xgettimeofday(&now, 0);
3af7813d
RK
229 delta.tv_sec = t->when.tv_sec - now.tv_sec;
230 delta.tv_usec = t->when.tv_usec - now.tv_usec;
460b9539 231 if(delta.tv_usec < 0) {
232 delta.tv_usec += 1000000;
233 --delta.tv_sec;
234 }
235 if(delta.tv_sec < 0)
236 delta.tv_sec = delta.tv_usec = 0;
237 n = select(maxfd + 1,
238 &ev->mode[ev_read].tripped,
239 &ev->mode[ev_write].tripped,
240 &ev->mode[ev_except].tripped,
241 &delta);
242 } else {
243 n = select(maxfd + 1,
244 &ev->mode[ev_read].tripped,
245 &ev->mode[ev_write].tripped,
246 &ev->mode[ev_except].tripped,
247 0);
248 }
249 } while(n < 0 && errno == EINTR);
250 xsigprocmask(SIG_BLOCK, &ev->sigmask, 0);
251 if(n < 0) {
252 error(errno, "error calling select");
e8c92ba7
RK
253 if(errno == EBADF) {
254 /* If there's a bad FD in the mix then check them all and log what we
255 * find, to ease debugging */
256 for(mode = 0; mode < ev_nmodes; ++mode) {
257 for(n = 0; n < ev->mode[mode].nfds; ++n) {
258 const int fd = ev->mode[mode].fds[n].fd;
259
260 if(FD_ISSET(fd, &ev->mode[mode].enabled)
261 && fstat(fd, &sb) < 0)
34a3e246
RK
262 error(errno, "mode %s fstat %d (%s)",
263 modenames[mode], fd, ev->mode[mode].fds[n].what);
e8c92ba7 264 }
7958ad2f 265 for(n = 0; n <= maxfd; ++n)
34a3e246
RK
266 if(FD_ISSET(n, &ev->mode[mode].enabled)
267 && fstat(n, &sb) < 0)
268 error(errno, "mode %s fstat %d", modenames[mode], n);
e8c92ba7
RK
269 }
270 }
460b9539 271 return -1;
272 }
273 if(n > 0) {
274 /* if anything deranges the meaning of an fd, or re-orders the
275 * fds[] tables, we'd better give up; such operations will
276 * therefore set @escape@. */
277 ev->escape = 0;
278 for(mode = 0; mode < ev_nmodes && !ev->escape; ++mode)
279 for(n = 0; n < ev->mode[mode].nfds && !ev->escape; ++n) {
280 int fd = ev->mode[mode].fds[n].fd;
281 if(FD_ISSET(fd, &ev->mode[mode].tripped)) {
282 D(("calling %s fd %d callback %p %p", modenames[mode], fd,
283 (void *)ev->mode[mode].fds[n].callback,
284 ev->mode[mode].fds[n].u));
285 ret = ev->mode[mode].fds[n].callback(ev, fd,
286 ev->mode[mode].fds[n].u);
287 if(ret)
288 return ret;
289 }
290 }
291 }
292 /* we'll pick up timeouts back round the loop */
293 }
294}
295
296/* file descriptors ***********************************************************/
297
768d7355
RK
298/** @brief Register a file descriptor
299 * @param ev Event loop
300 * @param mode @c ev_read or @c ev_write
301 * @param fd File descriptor
302 * @param callback Called when @p is readable/writable
303 * @param u Passed to @p callback
304 * @param what Text description
305 * @return 0 on success, non-0 on error
306 *
307 * Sets @ref ev_source::escape, so no further processing of file descriptors
308 * will occur this time round the event loop.
309 */
460b9539 310int ev_fd(ev_source *ev,
311 ev_fdmode mode,
312 int fd,
313 ev_fd_callback *callback,
e8c92ba7
RK
314 void *u,
315 const char *what) {
460b9539 316 int n;
317
318 D(("registering %s fd %d callback %p %p", modenames[mode], fd,
319 (void *)callback, u));
320 assert(mode < ev_nmodes);
321 if(ev->mode[mode].nfds >= ev->mode[mode].fdslots) {
322 ev->mode[mode].fdslots = (ev->mode[mode].fdslots
323 ? 2 * ev->mode[mode].fdslots : 16);
324 D(("expanding %s fd table to %d entries", modenames[mode],
325 ev->mode[mode].fdslots));
326 ev->mode[mode].fds = xrealloc(ev->mode[mode].fds,
327 ev->mode[mode].fdslots * sizeof (struct fd));
328 }
329 n = ev->mode[mode].nfds++;
330 FD_SET(fd, &ev->mode[mode].enabled);
331 ev->mode[mode].fds[n].fd = fd;
332 ev->mode[mode].fds[n].callback = callback;
333 ev->mode[mode].fds[n].u = u;
e8c92ba7 334 ev->mode[mode].fds[n].what = what;
460b9539 335 if(fd > ev->mode[mode].maxfd)
336 ev->mode[mode].maxfd = fd;
337 ev->escape = 1;
338 return 0;
339}
340
768d7355
RK
341/** @brief Cancel a file descriptor
342 * @param ev Event loop
343 * @param mode @c ev_read or @c ev_write
344 * @param fd File descriptor
345 * @return 0 on success, non-0 on error
346 *
347 * Sets @ref ev_source::escape, so no further processing of file descriptors
348 * will occur this time round the event loop.
349 */
460b9539 350int ev_fd_cancel(ev_source *ev, ev_fdmode mode, int fd) {
351 int n;
352 int maxfd;
353
354 D(("cancelling mode %s fd %d", modenames[mode], fd));
355 /* find the right struct fd */
356 for(n = 0; n < ev->mode[mode].nfds && fd != ev->mode[mode].fds[n].fd; ++n)
357 ;
358 assert(n < ev->mode[mode].nfds);
359 /* swap in the last fd and reduce the count */
360 if(n != ev->mode[mode].nfds - 1)
361 ev->mode[mode].fds[n] = ev->mode[mode].fds[ev->mode[mode].nfds - 1];
362 --ev->mode[mode].nfds;
363 /* if that was the biggest fd, find the new biggest one */
364 if(fd == ev->mode[mode].maxfd) {
365 maxfd = 0;
366 for(n = 0; n < ev->mode[mode].nfds; ++n)
367 if(ev->mode[mode].fds[n].fd > maxfd)
368 maxfd = ev->mode[mode].fds[n].fd;
369 ev->mode[mode].maxfd = maxfd;
370 }
371 /* don't tell select about this fd any more */
372 FD_CLR(fd, &ev->mode[mode].enabled);
373 ev->escape = 1;
374 return 0;
375}
376
768d7355
RK
377/** @brief Re-enable a file descriptor
378 * @param ev Event loop
379 * @param mode @c ev_read or @c ev_write
380 * @param fd File descriptor
381 * @return 0 on success, non-0 on error
382 *
383 * It is harmless if @p fd is currently disabled, but it must not have been
384 * cancelled.
385 */
460b9539 386int ev_fd_enable(ev_source *ev, ev_fdmode mode, int fd) {
38b8221f 387 assert(fd >= 0);
460b9539 388 D(("enabling mode %s fd %d", modenames[mode], fd));
389 FD_SET(fd, &ev->mode[mode].enabled);
390 return 0;
391}
392
768d7355
RK
393/** @brief Temporarily disable a file descriptor
394 * @param ev Event loop
395 * @param mode @c ev_read or @c ev_write
396 * @param fd File descriptor
397 * @return 0 on success, non-0 on error
398 *
399 * Re-enable with ev_fd_enable(). It is harmless if @p fd is already disabled,
400 * but it must not have been cancelled.
401 */
460b9539 402int ev_fd_disable(ev_source *ev, ev_fdmode mode, int fd) {
403 D(("disabling mode %s fd %d", modenames[mode], fd));
404 FD_CLR(fd, &ev->mode[mode].enabled);
405 FD_CLR(fd, &ev->mode[mode].tripped);
75d64210
RK
406 /* Suppress any pending callbacks */
407 ev->escape = 1;
460b9539 408 return 0;
409}
410
768d7355
RK
411/** @brief Log a report of file descriptor state */
412void ev_report(ev_source *ev) {
413 int n, fd;
414 ev_fdmode mode;
415 struct dynstr d[1];
416 char b[4096];
417
0fa83caa
RK
418 if(!debugging)
419 return;
768d7355
RK
420 dynstr_init(d);
421 for(mode = 0; mode < ev_nmodes; ++mode) {
0fa83caa 422 D(("mode %s maxfd %d", modenames[mode], ev->mode[mode].maxfd));
768d7355
RK
423 for(n = 0; n < ev->mode[mode].nfds; ++n) {
424 fd = ev->mode[mode].fds[n].fd;
0fa83caa
RK
425 D(("fd %s %d%s%s (%s)", modenames[mode], fd,
426 FD_ISSET(fd, &ev->mode[mode].enabled) ? " enabled" : "",
427 FD_ISSET(fd, &ev->mode[mode].tripped) ? " tripped" : "",
428 ev->mode[mode].fds[n].what));
768d7355
RK
429 }
430 d->nvec = 0;
431 for(fd = 0; fd <= ev->mode[mode].maxfd; ++fd) {
432 if(!FD_ISSET(fd, &ev->mode[mode].enabled))
433 continue;
434 for(n = 0; n < ev->mode[mode].nfds; ++n) {
435 if(ev->mode[mode].fds[n].fd == fd)
436 break;
437 }
438 if(n < ev->mode[mode].nfds)
34a3e246 439 snprintf(b, sizeof b, "%d(%s)", fd, ev->mode[mode].fds[n].what);
768d7355 440 else
34a3e246 441 snprintf(b, sizeof b, "%d", fd);
768d7355
RK
442 dynstr_append(d, ' ');
443 dynstr_append_string(d, b);
444 }
445 dynstr_terminate(d);
0fa83caa 446 D(("%s enabled:%s", modenames[mode], d->vec));
768d7355
RK
447 }
448}
449
460b9539 450/* timeouts *******************************************************************/
451
768d7355
RK
452/** @brief Register a timeout
453 * @param ev Event source
3149c1e2 454 * @param handlep Where to store timeout handle, or @c NULL
768d7355
RK
455 * @param when Earliest time to call @p callback, or @c NULL
456 * @param callback Function to call at or after @p when
457 * @param u Passed to @p callback
458 * @return 0 on success, non-0 on error
459 *
460 * If @p when is a null pointer then a time of 0 is assumed. The effect is to
461 * call the timeout handler from ev_run() next time around the event loop.
462 * This is used internally to schedule various operations if it is not
463 * convenient to call them from the current place in the call stack, or
464 * externally to ensure that other clients of the event loop get a look in when
465 * performing some lengthy operation.
466 */
460b9539 467int ev_timeout(ev_source *ev,
468 ev_timeout_handle *handlep,
469 const struct timeval *when,
470 ev_timeout_callback *callback,
471 void *u) {
3af7813d 472 struct timeout *t;
460b9539 473
474 D(("registering timeout at %ld.%ld callback %p %p",
475 when ? (long)when->tv_sec : 0, when ? (long)when->tv_usec : 0,
476 (void *)callback, u));
477 t = xmalloc(sizeof *t);
478 if(when)
479 t->when = *when;
480 t->callback = callback;
481 t->u = u;
3af7813d
RK
482 t->active = 1;
483 timeout_heap_insert(ev->timeouts, t);
460b9539 484 if(handlep)
485 *handlep = t;
486 return 0;
487}
488
768d7355
RK
489/** @brief Cancel a timeout
490 * @param ev Event loop
cb9a695c 491 * @param handle Handle returned from ev_timeout(), or 0
768d7355 492 * @return 0 on success, non-0 on error
cb9a695c
RK
493 *
494 * If @p handle is 0 then this is a no-op.
768d7355 495 */
3af7813d 496int ev_timeout_cancel(ev_source attribute((unused)) *ev,
460b9539 497 ev_timeout_handle handle) {
3af7813d 498 struct timeout *t = handle;
460b9539 499
3af7813d
RK
500 if(t)
501 t->active = 0;
502 return 0;
460b9539 503}
504
505/* signals ********************************************************************/
506
768d7355
RK
507/** @brief Mapping of signals to pipe write ends
508 *
509 * The pipes are per-event loop, it's possible in theory for there to be
510 * multiple event loops (e.g. in different threads), although in fact DisOrder
511 * does not do this.
512 */
460b9539 513static int sigfd[NSIG];
514
768d7355
RK
515/** @brief The signal handler
516 * @param s Signal number
517 *
518 * Writes to @c sigfd[s].
519 */
460b9539 520static void sighandler(int s) {
521 unsigned char sc = s;
522 static const char errmsg[] = "error writing to signal pipe";
523
524 /* probably the reader has stopped listening for some reason */
525 if(write(sigfd[s], &sc, 1) < 0) {
526 write(2, errmsg, sizeof errmsg - 1);
527 abort();
528 }
529}
530
768d7355 531/** @brief Read callback for signals */
460b9539 532static int signal_read(ev_source *ev,
533 int attribute((unused)) fd,
534 void attribute((unused)) *u) {
535 unsigned char s;
536 int n;
537 int ret;
538
539 if((n = read(ev->sigpipe[0], &s, 1)) == 1)
540 if((ret = ev->signals[s].callback(ev, s, ev->signals[s].u)))
541 return ret;
542 assert(n != 0);
543 if(n < 0 && (errno != EINTR && errno != EAGAIN)) {
544 error(errno, "error reading from signal pipe %d", ev->sigpipe[0]);
545 return -1;
546 }
547 return 0;
548}
549
768d7355 550/** @brief Close the signal pipe */
460b9539 551static void close_sigpipe(ev_source *ev) {
552 int save_errno = errno;
553
554 xclose(ev->sigpipe[0]);
555 xclose(ev->sigpipe[1]);
556 ev->sigpipe[0] = ev->sigpipe[1] = -1;
557 errno = save_errno;
558}
559
768d7355
RK
560/** @brief Register a signal handler
561 * @param ev Event loop
562 * @param sig Signal to handle
563 * @param callback Called when signal is delivered
564 * @param u Passed to @p callback
565 * @return 0 on success, non-0 on error
566 *
567 * Note that @p callback is called from inside ev_run(), not from inside the
568 * signal handler, so the usual restrictions on signal handlers do not apply.
569 */
460b9539 570int ev_signal(ev_source *ev,
571 int sig,
572 ev_signal_callback *callback,
573 void *u) {
574 int n;
575 struct sigaction sa;
576
577 D(("registering signal %d handler callback %p %p", sig, (void *)callback, u));
578 assert(sig > 0);
579 assert(sig < NSIG);
580 assert(sig <= UCHAR_MAX);
581 if(ev->sigpipe[0] == -1) {
582 D(("creating signal pipe"));
583 xpipe(ev->sigpipe);
584 D(("signal pipe is %d, %d", ev->sigpipe[0], ev->sigpipe[1]));
585 for(n = 0; n < 2; ++n) {
586 nonblock(ev->sigpipe[n]);
587 cloexec(ev->sigpipe[n]);
588 }
e8c92ba7 589 if(ev_fd(ev, ev_read, ev->sigpipe[0], signal_read, 0, "sigpipe read")) {
460b9539 590 close_sigpipe(ev);
591 return -1;
592 }
593 }
594 sigaddset(&ev->sigmask, sig);
595 xsigprocmask(SIG_BLOCK, &ev->sigmask, 0);
596 sigfd[sig] = ev->sigpipe[1];
597 ev->signals[sig].callback = callback;
598 ev->signals[sig].u = u;
599 sa.sa_handler = sighandler;
600 sigfillset(&sa.sa_mask);
601 sa.sa_flags = SA_RESTART;
602 xsigaction(sig, &sa, &ev->signals[sig].oldsa);
603 ev->escape = 1;
604 return 0;
605}
606
768d7355
RK
607/** @brief Cancel a signal handler
608 * @param ev Event loop
609 * @param sig Signal to cancel
610 * @return 0 on success, non-0 on error
611 */
460b9539 612int ev_signal_cancel(ev_source *ev,
613 int sig) {
614 sigset_t ss;
615
616 xsigaction(sig, &ev->signals[sig].oldsa, 0);
617 ev->signals[sig].callback = 0;
618 ev->escape = 1;
619 sigdelset(&ev->sigmask, sig);
620 sigemptyset(&ss);
621 sigaddset(&ss, sig);
622 xsigprocmask(SIG_UNBLOCK, &ss, 0);
623 return 0;
624}
625
768d7355
RK
626/** @brief Clean up signal handling
627 * @param ev Event loop
628 *
629 * This function can be called from inside a fork. It restores signal
630 * handlers, unblocks the signals, and closes the signal pipe for @p ev.
631 */
460b9539 632void ev_signal_atfork(ev_source *ev) {
633 int sig;
634
635 if(ev->sigpipe[0] != -1) {
636 /* revert any handled signals to their original state */
637 for(sig = 1; sig < NSIG; ++sig) {
638 if(ev->signals[sig].callback != 0)
639 xsigaction(sig, &ev->signals[sig].oldsa, 0);
640 }
641 /* and then unblock them */
642 xsigprocmask(SIG_UNBLOCK, &ev->sigmask, 0);
643 /* don't want a copy of the signal pipe open inside the fork */
644 xclose(ev->sigpipe[0]);
645 xclose(ev->sigpipe[1]);
646 }
647}
648
649/* child processes ************************************************************/
650
768d7355 651/** @brief Called on SIGCHLD */
460b9539 652static int sigchld_callback(ev_source *ev,
653 int attribute((unused)) sig,
654 void attribute((unused)) *u) {
655 struct rusage ru;
656 pid_t r;
657 int status, n, ret, revisit;
658
659 do {
660 revisit = 0;
661 for(n = 0; n < ev->nchildren; ++n) {
662 r = wait4(ev->children[n].pid,
663 &status,
664 ev->children[n].options | WNOHANG,
665 &ru);
666 if(r > 0) {
667 ev_child_callback *c = ev->children[n].callback;
668 void *cu = ev->children[n].u;
669
670 if(WIFEXITED(status) || WIFSIGNALED(status))
671 ev_child_cancel(ev, r);
672 revisit = 1;
673 if((ret = c(ev, r, status, &ru, cu)))
674 return ret;
675 } else if(r < 0) {
676 /* We should "never" get an ECHILD but it can in fact happen. For
677 * instance on Linux 2.4.31, and probably other versions, if someone
678 * straces a child process and then a different child process
679 * terminates, when we wait4() the trace process we will get ECHILD
680 * because it has been reparented to strace. Obviously this is a
681 * hopeless design flaw in the tracing infrastructure, but we don't
682 * want the disorder server to bomb out because of it. So we just log
683 * the problem and ignore it.
684 */
685 error(errno, "error calling wait4 for PID %lu (broken ptrace?)",
686 (unsigned long)ev->children[n].pid);
687 if(errno != ECHILD)
688 return -1;
689 }
690 }
691 } while(revisit);
692 return 0;
693}
694
768d7355
RK
695/** @brief Configure event loop for child process handling
696 * @return 0 on success, non-0 on error
697 *
698 * Currently at most one event loop can handle child processes and it must be
699 * distinguished from others by calling this function on it. This could be
700 * fixed but since no process ever makes use of more than one event loop there
701 * is no need.
702 */
460b9539 703int ev_child_setup(ev_source *ev) {
704 D(("installing SIGCHLD handler"));
705 return ev_signal(ev, SIGCHLD, sigchld_callback, 0);
706}
707
768d7355
RK
708/** @brief Wait for a child process to terminate
709 * @param ev Event loop
710 * @param pid Process ID of child
711 * @param options Options to pass to @c wait4()
712 * @param callback Called when child terminates (or possibly when it stops)
713 * @param u Passed to @p callback
714 * @return 0 on success, non-0 on error
715 *
716 * You must have called ev_child_setup() on @p ev once first.
717 */
460b9539 718int ev_child(ev_source *ev,
719 pid_t pid,
720 int options,
721 ev_child_callback *callback,
722 void *u) {
723 int n;
724
725 D(("registering child handling %ld options %d callback %p %p",
726 (long)pid, options, (void *)callback, u));
727 assert(ev->signals[SIGCHLD].callback == sigchld_callback);
728 if(ev->nchildren >= ev->nchildslots) {
729 ev->nchildslots = ev->nchildslots ? 2 * ev->nchildslots : 16;
730 ev->children = xrealloc(ev->children,
731 ev->nchildslots * sizeof (struct child));
732 }
733 n = ev->nchildren++;
734 ev->children[n].pid = pid;
735 ev->children[n].options = options;
736 ev->children[n].callback = callback;
737 ev->children[n].u = u;
738 return 0;
739}
740
768d7355
RK
741/** @brief Stop waiting for a child process
742 * @param ev Event loop
743 * @param pid Child process ID
744 * @return 0 on success, non-0 on error
745 */
460b9539 746int ev_child_cancel(ev_source *ev,
747 pid_t pid) {
748 int n;
749
750 for(n = 0; n < ev->nchildren && ev->children[n].pid != pid; ++n)
751 ;
752 assert(n < ev->nchildren);
753 if(n != ev->nchildren - 1)
754 ev->children[n] = ev->children[ev->nchildren - 1];
755 --ev->nchildren;
756 return 0;
757}
758
759/* socket listeners ***********************************************************/
760
768d7355 761/** @brief State for a socket listener */
460b9539 762struct listen_state {
763 ev_listen_callback *callback;
764 void *u;
765};
766
768d7355 767/** @brief Called when a listenign socket is readable */
460b9539 768static int listen_callback(ev_source *ev, int fd, void *u) {
769 const struct listen_state *l = u;
770 int newfd;
771 union {
772 struct sockaddr_in in;
773#if HAVE_STRUCT_SOCKADDR_IN6
774 struct sockaddr_in6 in6;
775#endif
776 struct sockaddr_un un;
777 struct sockaddr sa;
778 } addr;
779 socklen_t addrlen;
780 int ret;
781
782 D(("callback for listener fd %d", fd));
783 while((addrlen = sizeof addr),
784 (newfd = accept(fd, &addr.sa, &addrlen)) >= 0) {
785 if((ret = l->callback(ev, newfd, &addr.sa, addrlen, l->u)))
786 return ret;
787 }
788 switch(errno) {
789 case EINTR:
790 case EAGAIN:
791 break;
792#ifdef ECONNABORTED
793 case ECONNABORTED:
794 error(errno, "error calling accept");
795 break;
796#endif
797#ifdef EPROTO
798 case EPROTO:
799 /* XXX on some systems EPROTO should be fatal, but we don't know if
800 * we're running on one of them */
801 error(errno, "error calling accept");
802 break;
803#endif
804 default:
805 fatal(errno, "error calling accept");
806 break;
807 }
808 if(errno != EINTR && errno != EAGAIN)
809 error(errno, "error calling accept");
810 return 0;
811}
812
768d7355
RK
813/** @brief Listen on a socket for inbound stream connections
814 * @param ev Event source
815 * @param fd File descriptor of socket
816 * @param callback Called when a new connection arrives
817 * @param u Passed to @p callback
818 * @param what Text description of socket
819 * @return 0 on success, non-0 on error
820 */
460b9539 821int ev_listen(ev_source *ev,
822 int fd,
823 ev_listen_callback *callback,
e8c92ba7
RK
824 void *u,
825 const char *what) {
460b9539 826 struct listen_state *l = xmalloc(sizeof *l);
827
828 D(("registering listener fd %d callback %p %p", fd, (void *)callback, u));
829 l->callback = callback;
830 l->u = u;
e8c92ba7 831 return ev_fd(ev, ev_read, fd, listen_callback, l, what);
460b9539 832}
833
768d7355
RK
834/** @brief Stop listening on a socket
835 * @param ev Event loop
836 * @param fd File descriptor of socket
837 * @return 0 on success, non-0 on error
838 */
460b9539 839int ev_listen_cancel(ev_source *ev, int fd) {
840 D(("cancelling listener fd %d", fd));
841 return ev_fd_cancel(ev, ev_read, fd);
842}
843
844/* buffer *********************************************************************/
845
768d7355 846/** @brief Buffer structure */
460b9539 847struct buffer {
848 char *base, *start, *end, *top;
849};
850
768d7355 851/* @brief Make sure there is @p bytes available at @c b->end */
460b9539 852static void buffer_space(struct buffer *b, size_t bytes) {
853 D(("buffer_space %p %p %p %p want %lu",
854 (void *)b->base, (void *)b->start, (void *)b->end, (void *)b->top,
855 (unsigned long)bytes));
856 if(b->start == b->end)
857 b->start = b->end = b->base;
858 if((size_t)(b->top - b->end) < bytes) {
859 if((size_t)((b->top - b->end) + (b->start - b->base)) < bytes) {
860 size_t newspace = b->end - b->start + bytes, n;
861 char *newbase;
862
863 for(n = 16; n < newspace; n *= 2)
864 ;
865 newbase = xmalloc_noptr(n);
866 memcpy(newbase, b->start, b->end - b->start);
867 b->base = newbase;
868 b->end = newbase + (b->end - b->start);
869 b->top = newbase + n;
870 b->start = newbase; /* must be last */
871 } else {
872 memmove(b->base, b->start, b->end - b->start);
873 b->end = b->base + (b->end - b->start);
874 b->start = b->base;
875 }
876 }
877 D(("result %p %p %p %p",
878 (void *)b->base, (void *)b->start, (void *)b->end, (void *)b->top));
879}
880
75d64210 881/* readers and writers *******************************************************/
460b9539 882
768d7355 883/** @brief State structure for a buffered writer */
460b9539 884struct ev_writer {
75d64210 885 /** @brief Sink used for writing to the buffer */
460b9539 886 struct sink s;
75d64210
RK
887
888 /** @brief Output buffer */
460b9539 889 struct buffer b;
75d64210
RK
890
891 /** @brief File descriptor to write to */
460b9539 892 int fd;
75d64210
RK
893
894 /** @brief Set if there'll be no more output */
460b9539 895 int eof;
75d64210
RK
896
897 /** @brief Error/termination callback */
460b9539 898 ev_error_callback *callback;
75d64210
RK
899
900 /** @brief Passed to @p callback */
460b9539 901 void *u;
75d64210
RK
902
903 /** @brief Parent event source */
460b9539 904 ev_source *ev;
cb9a695c
RK
905
906 /** @brief Maximum amount of time between succesful writes, 0 = don't care */
907 int timebound;
908 /** @brief Maximum amount of data to buffer, 0 = don't care */
909 int spacebound;
75d64210
RK
910 /** @brief Error code to pass to @p callback (see writer_shutdown()) */
911 int error;
cb9a695c
RK
912 /** @brief Timeout handle for @p timebound (or 0) */
913 ev_timeout_handle timeout;
914
75d64210 915 /** @brief Description of this writer */
cb9a695c 916 const char *what;
75d64210
RK
917
918 /** @brief Tied reader or 0 */
919 ev_reader *reader;
d742bb47
RK
920
921 /** @brief Set when abandoned */
922 int abandoned;
460b9539 923};
924
75d64210
RK
925/** @brief State structure for a buffered reader */
926struct ev_reader {
927 /** @brief Input buffer */
928 struct buffer b;
929 /** @brief File descriptor read from */
930 int fd;
931 /** @brief Called when new data is available */
932 ev_reader_callback *callback;
933 /** @brief Called on error and shutdown */
934 ev_error_callback *error_callback;
935 /** @brief Passed to @p callback and @p error_callback */
936 void *u;
937 /** @brief Parent event loop */
938 ev_source *ev;
939 /** @brief Set when EOF is detected */
940 int eof;
941 /** @brief Error code to pass to error callback */
942 int error;
943 /** @brief Tied writer or NULL */
944 ev_writer *writer;
945};
946
947/* buffered writer ************************************************************/
948
949/** @brief Shut down the writer
950 *
951 * This is called to shut down a writer. The error callback is not called
952 * through any other path. Also we do not cancel @p fd from anywhere else,
953 * though we might disable it.
954 *
955 * It has the signature of a timeout callback so that it can be called from a
956 * time=0 timeout.
cb9a695c
RK
957 *
958 * Calls @p callback with @p w->syntherr as the error code (which might be 0).
959 */
960static int writer_shutdown(ev_source *ev,
961 const attribute((unused)) struct timeval *now,
962 void *u) {
963 ev_writer *w = u;
964
e4a9c7c5 965 if(w->fd == -1)
75d64210 966 return 0; /* already shut down */
0fa83caa 967 D(("writer_shutdown fd=%d error=%d", w->fd, w->error));
cb9a695c 968 ev_timeout_cancel(ev, w->timeout);
75d64210 969 ev_fd_cancel(ev, ev_write, w->fd);
cb9a695c 970 w->timeout = 0;
75d64210 971 if(w->reader) {
0fa83caa 972 D(("found a tied reader"));
75d64210
RK
973 /* If there is a reader still around we just untie it */
974 w->reader->writer = 0;
975 shutdown(w->fd, SHUT_WR); /* there'll be no more writes */
976 } else {
0fa83caa 977 D(("no tied reader"));
75d64210
RK
978 /* There's no reader so we are free to close the FD */
979 xclose(w->fd);
980 }
e4a9c7c5 981 w->fd = -1;
75d64210 982 return w->callback(ev, w->error, w->u);
cb9a695c
RK
983}
984
985/** @brief Called when a writer's @p timebound expires */
986static int writer_timebound_exceeded(ev_source *ev,
75d64210 987 const struct timeval *now,
cb9a695c
RK
988 void *u) {
989 ev_writer *const w = u;
990
d742bb47
RK
991 if(!w->abandoned) {
992 w->abandoned = 1;
993 error(0, "abandoning writer '%s' because no writes within %ds",
994 w->what, w->timebound);
995 w->error = ETIMEDOUT;
996 }
75d64210 997 return writer_shutdown(ev, now, u);
cb9a695c
RK
998}
999
1000/** @brief Set the time bound callback (if not set already) */
1001static void writer_set_timebound(ev_writer *w) {
1002 if(w->timebound && !w->timeout) {
1003 struct timeval when;
1004 ev_source *const ev = w->ev;
1005
1006 xgettimeofday(&when, 0);
1007 when.tv_sec += w->timebound;
1008 ev_timeout(ev, &w->timeout, &when, writer_timebound_exceeded, w);
1009 }
1010}
1011
768d7355 1012/** @brief Called when a writer's file descriptor is writable */
460b9539 1013static int writer_callback(ev_source *ev, int fd, void *u) {
cb9a695c 1014 ev_writer *const w = u;
460b9539 1015 int n;
1016
1017 n = write(fd, w->b.start, w->b.end - w->b.start);
1018 D(("callback for writer fd %d, %ld bytes, n=%d, errno=%d",
1019 fd, (long)(w->b.end - w->b.start), n, errno));
1020 if(n >= 0) {
75d64210 1021 /* Consume bytes from the buffer */
460b9539 1022 w->b.start += n;
75d64210 1023 /* Suppress any outstanding timeout */
cb9a695c
RK
1024 ev_timeout_cancel(ev, w->timeout);
1025 w->timeout = 0;
460b9539 1026 if(w->b.start == w->b.end) {
75d64210 1027 /* The buffer is empty */
460b9539 1028 if(w->eof) {
75d64210
RK
1029 /* We're done, we can shut down this writer */
1030 w->error = 0;
1031 return writer_shutdown(ev, 0, w);
460b9539 1032 } else
75d64210
RK
1033 /* There might be more to come but we don't need writer_callback() to
1034 * be called for the time being */
460b9539 1035 ev_fd_disable(ev, ev_write, fd);
cb9a695c 1036 } else
75d64210
RK
1037 /* The buffer isn't empty, set a timeout so we give up if we don't manage
1038 * to write some more within a reasonable time */
cb9a695c 1039 writer_set_timebound(w);
460b9539 1040 } else {
1041 switch(errno) {
1042 case EINTR:
1043 case EAGAIN:
1044 break;
1045 default:
75d64210
RK
1046 w->error = errno;
1047 return writer_shutdown(ev, 0, w);
460b9539 1048 }
1049 }
1050 return 0;
1051}
1052
768d7355
RK
1053/** @brief Write bytes to a writer's buffer
1054 *
1055 * This is the sink write callback.
1056 *
1057 * Calls ev_fd_enable() if necessary (i.e. if the buffer was empty but
1058 * now is not).
1059 */
460b9539 1060static int ev_writer_write(struct sink *sk, const void *s, int n) {
1061 ev_writer *w = (ev_writer *)sk;
cb9a695c
RK
1062
1063 if(!n)
1064 return 0; /* avoid silliness */
38b8221f
RK
1065 if(w->fd == -1)
1066 error(0, "ev_writer_write on %s after shutdown", w->what);
75d64210
RK
1067 if(w->spacebound && w->b.end - w->b.start + n > w->spacebound) {
1068 /* The new buffer contents will exceed the space bound. We assume that the
cb9a695c
RK
1069 * remote client has gone away and TCP hasn't noticed yet, or that it's got
1070 * hopelessly stuck. */
d742bb47
RK
1071 if(!w->abandoned) {
1072 w->abandoned = 1;
1073 error(0, "abandoning writer '%s' because buffer has reached %td bytes",
1074 w->what, w->b.end - w->b.start);
1075 ev_fd_disable(w->ev, ev_write, w->fd);
1076 w->error = EPIPE;
1077 return ev_timeout(w->ev, 0, 0, writer_shutdown, w);
1078 } else
1079 return 0;
cb9a695c 1080 }
75d64210
RK
1081 /* Make sure there is space */
1082 buffer_space(&w->b, n);
1083 /* If the buffer was formerly empty then we'll need to re-enable the FD */
1084 if(w->b.start == w->b.end)
1085 ev_fd_enable(w->ev, ev_write, w->fd);
1086 memcpy(w->b.end, s, n);
1087 w->b.end += n;
1088 /* Arrange a timeout if there wasn't one set already */
cb9a695c 1089 writer_set_timebound(w);
460b9539 1090 return 0;
1091}
1092
768d7355
RK
1093/** @brief Create a new buffered writer
1094 * @param ev Event loop
1095 * @param fd File descriptor to write to
1096 * @param callback Called if an error occurs and when finished
1097 * @param u Passed to @p callback
1098 * @param what Text description
1099 * @return New writer or @c NULL
75d64210
RK
1100 *
1101 * Writers own their file descriptor and close it when they have finished with
1102 * it.
1103 *
1104 * If you pass the same fd to a reader and writer, you must tie them together
1105 * with ev_tie().
768d7355 1106 */
460b9539 1107ev_writer *ev_writer_new(ev_source *ev,
1108 int fd,
1109 ev_error_callback *callback,
e8c92ba7
RK
1110 void *u,
1111 const char *what) {
460b9539 1112 ev_writer *w = xmalloc(sizeof *w);
1113
1114 D(("registering writer fd %d callback %p %p", fd, (void *)callback, u));
1115 w->s.write = ev_writer_write;
1116 w->fd = fd;
1117 w->callback = callback;
1118 w->u = u;
1119 w->ev = ev;
cb9a695c
RK
1120 w->timebound = 10 * 60;
1121 w->spacebound = 512 * 1024;
1122 w->what = what;
e8c92ba7 1123 if(ev_fd(ev, ev_write, fd, writer_callback, w, what))
460b9539 1124 return 0;
75d64210 1125 /* Buffer is initially empty so we don't want a callback */
460b9539 1126 ev_fd_disable(ev, ev_write, fd);
1127 return w;
1128}
1129
cb9a695c
RK
1130/** @brief Get/set the time bound
1131 * @param w Writer
1132 * @param new_time_bound New bound or -1 for no change
1133 * @return Latest time bound
1134 *
1135 * If @p new_time_bound is negative then the current time bound is returned.
1136 * Otherwise it is set and the new value returned.
1137 *
1138 * The time bound is the number of seconds allowed between writes. If it takes
1139 * longer than this to flush a buffer then the peer will be assumed to be dead
1140 * and an error will be synthesized. 0 means "don't care". The default time
1141 * bound is 10 minutes.
1142 *
1143 * Note that this value does not take into account kernel buffering and
1144 * timeouts.
1145 */
1146int ev_writer_time_bound(ev_writer *w,
1147 int new_time_bound) {
1148 if(new_time_bound >= 0)
1149 w->timebound = new_time_bound;
1150 return w->timebound;
1151}
1152
1153/** @brief Get/set the space bound
1154 * @param w Writer
1155 * @param new_space_bound New bound or -1 for no change
1156 * @return Latest space bound
1157 *
1158 * If @p new_space_bound is negative then the current space bound is returned.
1159 * Otherwise it is set and the new value returned.
1160 *
1161 * The space bound is the number of bytes allowed between in the buffer. If
1162 * the buffer exceeds this size an error will be synthesized. 0 means "don't
1163 * care". The default space bound is 512Kbyte.
1164 *
1165 * Note that this value does not take into account kernel buffering.
1166 */
1167int ev_writer_space_bound(ev_writer *w,
1168 int new_space_bound) {
1169 if(new_space_bound >= 0)
1170 w->spacebound = new_space_bound;
1171 return w->spacebound;
1172}
1173
768d7355
RK
1174/** @brief Return the sink associated with a writer
1175 * @param w Writer
1176 * @return Pointer to sink
1177 *
1178 * Writing to the sink will arrange for those bytes to be written to the file
1179 * descriptor as and when it is writable.
1180 */
460b9539 1181struct sink *ev_writer_sink(ev_writer *w) {
f6033c46
RK
1182 if(!w)
1183 fatal(0, "ev_write_sink called with null writer");
460b9539 1184 return &w->s;
1185}
1186
768d7355
RK
1187/** @brief Close a writer
1188 * @param w Writer to close
1189 * @return 0 on success, non-0 on error
1190 *
1191 * Close a writer. No more bytes should be written to its sink.
1192 *
1193 * When the last byte has been written the callback will be called with an
1194 * error code of 0. It is guaranteed that this will NOT happen before
1195 * ev_writer_close() returns (although the file descriptor for the writer might
1196 * be cancelled by the time it returns).
1197 */
460b9539 1198int ev_writer_close(ev_writer *w) {
1199 D(("close writer fd %d", w->fd));
75d64210
RK
1200 if(w->eof)
1201 return 0; /* already closed */
460b9539 1202 w->eof = 1;
1203 if(w->b.start == w->b.end) {
75d64210
RK
1204 /* We're already finished */
1205 w->error = 0; /* no error */
460b9539 1206 return ev_timeout(w->ev, 0, 0, writer_shutdown, w);
1207 }
1208 return 0;
1209}
1210
768d7355
RK
1211/** @brief Attempt to flush a writer
1212 * @param w Writer to flush
1213 * @return 0 on success, non-0 on error
1214 *
1215 * Does a speculative write of any buffered data. Does not block if it cannot
1216 * be written.
1217 */
460b9539 1218int ev_writer_flush(ev_writer *w) {
1219 return writer_callback(w->ev, w->fd, w);
1220}
1221
1222/* buffered reader ************************************************************/
1223
49a773eb 1224/** @brief Shut down a reader
75d64210
RK
1225 *
1226 * This is the only path through which we cancel and close the file descriptor.
1227 * As with the writer case it is given timeout signature to allow it be
1228 * deferred to the next iteration of the event loop.
1229 *
1230 * We only call @p error_callback if @p error is nonzero (unlike the writer
1231 * case).
1232 */
1233static int reader_shutdown(ev_source *ev,
1234 const attribute((unused)) struct timeval *now,
1235 void *u) {
1236 ev_reader *const r = u;
1237
1238 if(r->fd == -1)
1239 return 0; /* already shut down */
0fa83caa 1240 D(("reader_shutdown fd=%d", r->fd));
75d64210
RK
1241 ev_fd_cancel(ev, ev_read, r->fd);
1242 r->eof = 1;
1243 if(r->writer) {
0fa83caa 1244 D(("found a tied writer"));
75d64210
RK
1245 /* If there is a writer still around we just untie it */
1246 r->writer->reader = 0;
1247 shutdown(r->fd, SHUT_RD); /* there'll be no more reads */
1248 } else {
0fa83caa 1249 D(("no tied writer found"));
75d64210
RK
1250 /* There's no writer so we are free to close the FD */
1251 xclose(r->fd);
1252 }
1253 r->fd = -1;
1254 if(r->error)
1255 return r->error_callback(ev, r->error, r->u);
1256 else
1257 return 0;
1258}
460b9539 1259
768d7355 1260/** @brief Called when a reader's @p fd is readable */
460b9539 1261static int reader_callback(ev_source *ev, int fd, void *u) {
1262 ev_reader *r = u;
1263 int n;
1264
1265 buffer_space(&r->b, 1);
1266 n = read(fd, r->b.end, r->b.top - r->b.end);
1267 D(("read fd %d buffer %d returned %d errno %d",
1268 fd, (int)(r->b.top - r->b.end), n, errno));
1269 if(n > 0) {
1270 r->b.end += n;
75d64210 1271 return r->callback(ev, r, r->b.start, r->b.end - r->b.start, 0, r->u);
460b9539 1272 } else if(n == 0) {
75d64210
RK
1273 /* No more read callbacks needed */
1274 ev_fd_disable(r->ev, ev_read, r->fd);
1275 ev_timeout(r->ev, 0, 0, reader_shutdown, r);
1276 /* Pass the remaining data and an eof indicator to the user */
1277 return r->callback(ev, r, r->b.start, r->b.end - r->b.start, 1, r->u);
460b9539 1278 } else {
1279 switch(errno) {
1280 case EINTR:
1281 case EAGAIN:
1282 break;
1283 default:
75d64210
RK
1284 /* Fatal error, kill the reader now */
1285 r->error = errno;
1286 return reader_shutdown(ev, 0, r);
460b9539 1287 }
1288 }
1289 return 0;
1290}
1291
768d7355
RK
1292/** @brief Create a new buffered reader
1293 * @param ev Event loop
1294 * @param fd File descriptor to read from
1295 * @param callback Called when new data is available
1296 * @param error_callback Called if an error occurs
1297 * @param u Passed to callbacks
1298 * @param what Text description
1299 * @return New reader or @c NULL
75d64210
RK
1300 *
1301 * Readers own their fd and close it when they are finished with it.
1302 *
1303 * If you pass the same fd to a reader and writer, you must tie them together
1304 * with ev_tie().
768d7355 1305 */
460b9539 1306ev_reader *ev_reader_new(ev_source *ev,
1307 int fd,
1308 ev_reader_callback *callback,
1309 ev_error_callback *error_callback,
e8c92ba7
RK
1310 void *u,
1311 const char *what) {
460b9539 1312 ev_reader *r = xmalloc(sizeof *r);
1313
1314 D(("registering reader fd %d callback %p %p %p",
1315 fd, (void *)callback, (void *)error_callback, u));
1316 r->fd = fd;
1317 r->callback = callback;
1318 r->error_callback = error_callback;
1319 r->u = u;
1320 r->ev = ev;
e8c92ba7 1321 if(ev_fd(ev, ev_read, fd, reader_callback, r, what))
460b9539 1322 return 0;
1323 return r;
1324}
1325
1326void ev_reader_buffer(ev_reader *r, size_t nbytes) {
1327 buffer_space(&r->b, nbytes - (r->b.end - r->b.start));
1328}
1329
768d7355
RK
1330/** @brief Consume @p n bytes from the reader's buffer
1331 * @param r Reader
1332 * @param n Number of bytes to consume
1333 *
1334 * Tells the reader than the next @p n bytes have been dealt with and can now
1335 * be discarded.
1336 */
460b9539 1337void ev_reader_consume(ev_reader *r, size_t n) {
1338 r->b.start += n;
1339}
1340
768d7355
RK
1341/** @brief Cancel a reader
1342 * @param r Reader
1343 * @return 0 on success, non-0 on error
75d64210
RK
1344 *
1345 * No further callbacks will be made, and the FD will be closed (in a later
1346 * iteration of the event loop).
768d7355 1347 */
460b9539 1348int ev_reader_cancel(ev_reader *r) {
1349 D(("cancel reader fd %d", r->fd));
75d64210
RK
1350 if(r->fd == -1)
1351 return 0; /* already thoroughly cancelled */
1352 ev_fd_disable(r->ev, ev_read, r->fd);
1353 return ev_timeout(r->ev, 0, 0, reader_shutdown, r);
460b9539 1354}
1355
768d7355
RK
1356/** @brief Temporarily disable a reader
1357 * @param r Reader
1358 * @return 0 on success, non-0 on error
1359 *
1360 * No further callbacks for this reader will be made. Re-enable with
1361 * ev_reader_enable().
1362 */
460b9539 1363int ev_reader_disable(ev_reader *r) {
1364 D(("disable reader fd %d", r->fd));
75d64210 1365 return ev_fd_disable(r->ev, ev_read, r->fd);
460b9539 1366}
1367
768d7355 1368/** @brief Called from ev_run() for ev_reader_incomplete() */
460b9539 1369static int reader_continuation(ev_source attribute((unused)) *ev,
1370 const attribute((unused)) struct timeval *now,
1371 void *u) {
1372 ev_reader *r = u;
1373
1374 D(("reader continuation callback fd %d", r->fd));
75d64210
RK
1375 /* If not at EOF turn the FD back on */
1376 if(!r->eof)
1377 if(ev_fd_enable(r->ev, ev_read, r->fd))
1378 return -1;
1379 /* We're already in a timeout callback so there's no reason we can't call the
1380 * user callback directly (compare ev_reader_enable()). */
1381 return r->callback(ev, r, r->b.start, r->b.end - r->b.start, r->eof, r->u);
460b9539 1382}
1383
768d7355
RK
1384/** @brief Arrange another callback
1385 * @param r reader
1386 * @return 0 on success, non-0 on error
1387 *
1388 * Indicates that the reader can process more input but would like to yield to
1389 * other clients of the event loop. Input will be disabled but it will be
1390 * re-enabled on the next iteration of the event loop and the read callback
1391 * will be called again (even if no further bytes are available).
1392 */
460b9539 1393int ev_reader_incomplete(ev_reader *r) {
1394 if(ev_fd_disable(r->ev, ev_read, r->fd)) return -1;
1395 return ev_timeout(r->ev, 0, 0, reader_continuation, r);
1396}
1397
1398static int reader_enabled(ev_source *ev,
1399 const attribute((unused)) struct timeval *now,
1400 void *u) {
1401 ev_reader *r = u;
1402
1403 D(("reader enabled callback fd %d", r->fd));
75d64210 1404 return r->callback(ev, r, r->b.start, r->b.end - r->b.start, r->eof, r->u);
460b9539 1405}
1406
768d7355
RK
1407/** @brief Re-enable reading
1408 * @param r reader
1409 * @return 0 on success, non-0 on error
1410 *
1411 * If there is unconsumed data then you get a callback next time round the
1412 * event loop even if nothing new has been read.
1413 *
1414 * The idea is in your read callback you come across a line (or whatever) that
1415 * can't be processed immediately. So you set up processing and disable
1416 * reading with ev_reader_disable(). Later when you finish processing you
1417 * re-enable. You'll automatically get another callback directly from the
1418 * event loop (i.e. not from inside ev_reader_enable()) so you can handle the
1419 * next line (or whatever) if the whole thing has in fact already arrived.
75d64210
RK
1420 *
1421 * The difference between this process and calling ev_reader_incomplete() is
1422 * ev_reader_incomplete() deals with the case where you can process now but
1423 * would rather yield to other clients of the event loop, while using
1424 * ev_reader_disable() and ev_reader_enable() deals with the case where you
1425 * cannot process input yet because some other process is actually not
1426 * complete.
768d7355 1427 */
460b9539 1428int ev_reader_enable(ev_reader *r) {
1429 D(("enable reader fd %d", r->fd));
75d64210
RK
1430
1431 /* First if we're not at EOF then we re-enable reading */
1432 if(!r->eof)
1433 if(ev_fd_enable(r->ev, ev_read, r->fd))
1434 return -1;
1435 /* Arrange another callback next time round the event loop */
1436 return ev_timeout(r->ev, 0, 0, reader_enabled, r);
1437}
1438
1439/** @brief Tie a reader and a writer together
1440 * @param r Reader
1441 * @param w Writer
1442 * @return 0 on success, non-0 on error
1443 *
1444 * This function must be called if @p r and @p w share a file descritptor.
1445 */
1446int ev_tie(ev_reader *r, ev_writer *w) {
1447 assert(r->writer == 0);
1448 assert(w->reader == 0);
1449 r->writer = w;
1450 w->reader = r;
1451 return 0;
460b9539 1452}
1453
1454/*
1455Local Variables:
1456c-basic-offset:2
1457comment-column:40
1458fill-column:79
1459End:
1460*/