2 * This file is part of DisOrder.
3 * Copyright (C) 2004, 2005, 2007 Richard Kettlewell
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.
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.
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
21 * @brief DisOrder event loop
29 #include <sys/types.h>
30 #include <sys/resource.h>
39 #include <sys/socket.h>
40 #include <netinet/in.h>
51 /** @brief A timeout */
55 ev_timeout_callback *callback;
60 /** @brief A file descriptor in one mode */
63 ev_fd_callback *callback;
68 /** @brief All the file descriptors in a given mode */
70 /** @brief Mask of active file descriptors passed to @c select() */
73 /** @brief File descriptor mask returned from @c select() */
76 /** @brief Number of file descriptors in @p fds */
79 /** @brief Number of slots in @p fds */
82 /** @brief Array of all active file descriptors */
85 /** @brief Highest-numbered file descriptor or 0 */
89 /** @brief A signal handler */
91 struct sigaction oldsa;
92 ev_signal_callback *callback;
96 /** @brief A child process */
100 ev_child_callback *callback;
104 /** @brief An event loop */
106 /** @brief File descriptors, per mode */
107 struct fdmode mode[ev_nmodes];
109 /** @brief Sorted linked list of timeouts
111 * We could use @ref HEAP_TYPE now, but there aren't many timeouts.
113 struct timeout *timeouts;
115 /** @brief Array of handled signals */
116 struct signal signals[NSIG];
118 /** @brief Mask of handled signals */
121 /** @brief Escape early from handling of @c select() results
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.
128 /** @brief Signal handling pipe
130 * The signal handle writes signal numbers down this pipe.
134 /** @brief Number of child processes in @p children */
137 /** @brief Number of slots in @p children */
140 /** @brief Array of child processes */
141 struct child *children;
144 /** @brief Names of file descriptor modes */
145 static const char *modenames[] = { "read", "write", "except" };
147 /* utilities ******************************************************************/
149 /** @brief Great-than comparison for timevals
151 * Ought to be in @file lib/timeval.h
153 static inline int gt(const struct timeval *a, const struct timeval *b) {
154 if(a->tv_sec > b->tv_sec)
156 if(a->tv_sec == b->tv_sec
157 && a->tv_usec > b->tv_usec)
162 /** @brief Greater-than-or-equal comparison for timevals
164 * Ought to be in @file lib/timeval.h
166 static inline int ge(const struct timeval *a, const struct timeval *b) {
170 /* creation *******************************************************************/
172 /** @brief Create a new event loop */
173 ev_source *ev_new(void) {
174 ev_source *ev = xmalloc(sizeof *ev);
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);
185 /* event loop *****************************************************************/
187 /** @brief Run the event loop
188 * @return -1 on error, non-0 if any callback returned non-0
190 int ev_run(ev_source *ev) {
193 struct timeval delta;
197 struct timeout *t, **tt;
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);
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);
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;
229 xsigprocmask(SIG_UNBLOCK, &ev->sigmask, 0);
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;
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,
247 n = select(maxfd + 1,
248 &ev->mode[ev_read].tripped,
249 &ev->mode[ev_write].tripped,
250 &ev->mode[ev_except].tripped,
253 } while(n < 0 && errno == EINTR);
254 xsigprocmask(SIG_BLOCK, &ev->sigmask, 0);
256 error(errno, "error calling select");
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;
264 if(FD_ISSET(fd, &ev->mode[mode].enabled)
265 && fstat(fd, &sb) < 0)
266 error(errno, "mode %s fstat %d (%s)",
267 modenames[mode], fd, ev->mode[mode].fds[n].what);
269 for(n = 0; n < maxfd; ++n)
270 if(FD_ISSET(n, &ev->mode[mode].enabled)
271 && fstat(n, &sb) < 0)
272 error(errno, "mode %s fstat %d", modenames[mode], n);
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@. */
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);
296 /* we'll pick up timeouts back round the loop */
300 /* file descriptors ***********************************************************/
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
311 * Sets @ref ev_source::escape, so no further processing of file descriptors
312 * will occur this time round the event loop.
314 int ev_fd(ev_source *ev,
317 ev_fd_callback *callback,
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));
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;
338 ev->mode[mode].fds[n].what = what;
339 if(fd > ev->mode[mode].maxfd)
340 ev->mode[mode].maxfd = fd;
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
351 * Sets @ref ev_source::escape, so no further processing of file descriptors
352 * will occur this time round the event loop.
354 int ev_fd_cancel(ev_source *ev, ev_fdmode mode, int fd) {
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)
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) {
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;
375 /* don't tell select about this fd any more */
376 FD_CLR(fd, &ev->mode[mode].enabled);
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
387 * It is harmless if @p fd is currently disabled, but it must not have been
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);
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
402 * Re-enable with ev_fd_enable(). It is harmless if @p fd is already disabled,
403 * but it must not have been cancelled.
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);
412 /** @brief Log a report of file descriptor state */
413 void ev_report(ev_source *ev) {
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);
430 for(fd = 0; fd <= ev->mode[mode].maxfd; ++fd) {
431 if(!FD_ISSET(fd, &ev->mode[mode].enabled))
433 for(n = 0; n < ev->mode[mode].nfds; ++n) {
434 if(ev->mode[mode].fds[n].fd == fd)
437 if(n < ev->mode[mode].nfds)
438 snprintf(b, sizeof b, "%d(%s)", fd, ev->mode[mode].fds[n].what);
440 snprintf(b, sizeof b, "%d", fd);
441 dynstr_append(d, ' ');
442 dynstr_append_string(d, b);
445 info("%s enabled:%s", modenames[mode], d->vec);
449 /* timeouts *******************************************************************/
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
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.
466 int ev_timeout(ev_source *ev,
467 ev_timeout_handle *handlep,
468 const struct timeval *when,
469 ev_timeout_callback *callback,
471 struct timeout *t, *p, **pp;
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);
479 t->callback = callback;
482 while((p = *pp) && gt(&t->when, &p->when))
491 /** @brief Cancel a timeout
492 * @param ev Event loop
493 * @param handle Handle returned from ev_timeout()
494 * @return 0 on success, non-0 on error
496 int ev_timeout_cancel(ev_source *ev,
497 ev_timeout_handle handle) {
498 struct timeout *t = handle, *p, **pp;
500 for(pp = &ev->timeouts; (p = *pp) && p != t; pp = &p->next)
509 /* signals ********************************************************************/
511 /** @brief Mapping of signals to pipe write ends
513 * The pipes are per-event loop, it's possible in theory for there to be
514 * multiple event loops (e.g. in different threads), although in fact DisOrder
517 static int sigfd[NSIG];
519 /** @brief The signal handler
520 * @param s Signal number
522 * Writes to @c sigfd[s].
524 static void sighandler(int s) {
525 unsigned char sc = s;
526 static const char errmsg[] = "error writing to signal pipe";
528 /* probably the reader has stopped listening for some reason */
529 if(write(sigfd[s], &sc, 1) < 0) {
530 write(2, errmsg, sizeof errmsg - 1);
535 /** @brief Read callback for signals */
536 static int signal_read(ev_source *ev,
537 int attribute((unused)) fd,
538 void attribute((unused)) *u) {
543 if((n = read(ev->sigpipe[0], &s, 1)) == 1)
544 if((ret = ev->signals[s].callback(ev, s, ev->signals[s].u)))
547 if(n < 0 && (errno != EINTR && errno != EAGAIN)) {
548 error(errno, "error reading from signal pipe %d", ev->sigpipe[0]);
554 /** @brief Close the signal pipe */
555 static void close_sigpipe(ev_source *ev) {
556 int save_errno = errno;
558 xclose(ev->sigpipe[0]);
559 xclose(ev->sigpipe[1]);
560 ev->sigpipe[0] = ev->sigpipe[1] = -1;
564 /** @brief Register a signal handler
565 * @param ev Event loop
566 * @param sig Signal to handle
567 * @param callback Called when signal is delivered
568 * @param u Passed to @p callback
569 * @return 0 on success, non-0 on error
571 * Note that @p callback is called from inside ev_run(), not from inside the
572 * signal handler, so the usual restrictions on signal handlers do not apply.
574 int ev_signal(ev_source *ev,
576 ev_signal_callback *callback,
581 D(("registering signal %d handler callback %p %p", sig, (void *)callback, u));
584 assert(sig <= UCHAR_MAX);
585 if(ev->sigpipe[0] == -1) {
586 D(("creating signal pipe"));
588 D(("signal pipe is %d, %d", ev->sigpipe[0], ev->sigpipe[1]));
589 for(n = 0; n < 2; ++n) {
590 nonblock(ev->sigpipe[n]);
591 cloexec(ev->sigpipe[n]);
593 if(ev_fd(ev, ev_read, ev->sigpipe[0], signal_read, 0, "sigpipe read")) {
598 sigaddset(&ev->sigmask, sig);
599 xsigprocmask(SIG_BLOCK, &ev->sigmask, 0);
600 sigfd[sig] = ev->sigpipe[1];
601 ev->signals[sig].callback = callback;
602 ev->signals[sig].u = u;
603 sa.sa_handler = sighandler;
604 sigfillset(&sa.sa_mask);
605 sa.sa_flags = SA_RESTART;
606 xsigaction(sig, &sa, &ev->signals[sig].oldsa);
611 /** @brief Cancel a signal handler
612 * @param ev Event loop
613 * @param sig Signal to cancel
614 * @return 0 on success, non-0 on error
616 int ev_signal_cancel(ev_source *ev,
620 xsigaction(sig, &ev->signals[sig].oldsa, 0);
621 ev->signals[sig].callback = 0;
623 sigdelset(&ev->sigmask, sig);
626 xsigprocmask(SIG_UNBLOCK, &ss, 0);
630 /** @brief Clean up signal handling
631 * @param ev Event loop
633 * This function can be called from inside a fork. It restores signal
634 * handlers, unblocks the signals, and closes the signal pipe for @p ev.
636 void ev_signal_atfork(ev_source *ev) {
639 if(ev->sigpipe[0] != -1) {
640 /* revert any handled signals to their original state */
641 for(sig = 1; sig < NSIG; ++sig) {
642 if(ev->signals[sig].callback != 0)
643 xsigaction(sig, &ev->signals[sig].oldsa, 0);
645 /* and then unblock them */
646 xsigprocmask(SIG_UNBLOCK, &ev->sigmask, 0);
647 /* don't want a copy of the signal pipe open inside the fork */
648 xclose(ev->sigpipe[0]);
649 xclose(ev->sigpipe[1]);
653 /* child processes ************************************************************/
655 /** @brief Called on SIGCHLD */
656 static int sigchld_callback(ev_source *ev,
657 int attribute((unused)) sig,
658 void attribute((unused)) *u) {
661 int status, n, ret, revisit;
665 for(n = 0; n < ev->nchildren; ++n) {
666 r = wait4(ev->children[n].pid,
668 ev->children[n].options | WNOHANG,
671 ev_child_callback *c = ev->children[n].callback;
672 void *cu = ev->children[n].u;
674 if(WIFEXITED(status) || WIFSIGNALED(status))
675 ev_child_cancel(ev, r);
677 if((ret = c(ev, r, status, &ru, cu)))
680 /* We should "never" get an ECHILD but it can in fact happen. For
681 * instance on Linux 2.4.31, and probably other versions, if someone
682 * straces a child process and then a different child process
683 * terminates, when we wait4() the trace process we will get ECHILD
684 * because it has been reparented to strace. Obviously this is a
685 * hopeless design flaw in the tracing infrastructure, but we don't
686 * want the disorder server to bomb out because of it. So we just log
687 * the problem and ignore it.
689 error(errno, "error calling wait4 for PID %lu (broken ptrace?)",
690 (unsigned long)ev->children[n].pid);
699 /** @brief Configure event loop for child process handling
700 * @return 0 on success, non-0 on error
702 * Currently at most one event loop can handle child processes and it must be
703 * distinguished from others by calling this function on it. This could be
704 * fixed but since no process ever makes use of more than one event loop there
707 int ev_child_setup(ev_source *ev) {
708 D(("installing SIGCHLD handler"));
709 return ev_signal(ev, SIGCHLD, sigchld_callback, 0);
712 /** @brief Wait for a child process to terminate
713 * @param ev Event loop
714 * @param pid Process ID of child
715 * @param options Options to pass to @c wait4()
716 * @param callback Called when child terminates (or possibly when it stops)
717 * @param u Passed to @p callback
718 * @return 0 on success, non-0 on error
720 * You must have called ev_child_setup() on @p ev once first.
722 int ev_child(ev_source *ev,
725 ev_child_callback *callback,
729 D(("registering child handling %ld options %d callback %p %p",
730 (long)pid, options, (void *)callback, u));
731 assert(ev->signals[SIGCHLD].callback == sigchld_callback);
732 if(ev->nchildren >= ev->nchildslots) {
733 ev->nchildslots = ev->nchildslots ? 2 * ev->nchildslots : 16;
734 ev->children = xrealloc(ev->children,
735 ev->nchildslots * sizeof (struct child));
738 ev->children[n].pid = pid;
739 ev->children[n].options = options;
740 ev->children[n].callback = callback;
741 ev->children[n].u = u;
745 /** @brief Stop waiting for a child process
746 * @param ev Event loop
747 * @param pid Child process ID
748 * @return 0 on success, non-0 on error
750 int ev_child_cancel(ev_source *ev,
754 for(n = 0; n < ev->nchildren && ev->children[n].pid != pid; ++n)
756 assert(n < ev->nchildren);
757 if(n != ev->nchildren - 1)
758 ev->children[n] = ev->children[ev->nchildren - 1];
763 /* socket listeners ***********************************************************/
765 /** @brief State for a socket listener */
766 struct listen_state {
767 ev_listen_callback *callback;
771 /** @brief Called when a listenign socket is readable */
772 static int listen_callback(ev_source *ev, int fd, void *u) {
773 const struct listen_state *l = u;
776 struct sockaddr_in in;
777 #if HAVE_STRUCT_SOCKADDR_IN6
778 struct sockaddr_in6 in6;
780 struct sockaddr_un un;
786 D(("callback for listener fd %d", fd));
787 while((addrlen = sizeof addr),
788 (newfd = accept(fd, &addr.sa, &addrlen)) >= 0) {
789 if((ret = l->callback(ev, newfd, &addr.sa, addrlen, l->u)))
798 error(errno, "error calling accept");
803 /* XXX on some systems EPROTO should be fatal, but we don't know if
804 * we're running on one of them */
805 error(errno, "error calling accept");
809 fatal(errno, "error calling accept");
812 if(errno != EINTR && errno != EAGAIN)
813 error(errno, "error calling accept");
817 /** @brief Listen on a socket for inbound stream connections
818 * @param ev Event source
819 * @param fd File descriptor of socket
820 * @param callback Called when a new connection arrives
821 * @param u Passed to @p callback
822 * @param what Text description of socket
823 * @return 0 on success, non-0 on error
825 int ev_listen(ev_source *ev,
827 ev_listen_callback *callback,
830 struct listen_state *l = xmalloc(sizeof *l);
832 D(("registering listener fd %d callback %p %p", fd, (void *)callback, u));
833 l->callback = callback;
835 return ev_fd(ev, ev_read, fd, listen_callback, l, what);
838 /** @brief Stop listening on a socket
839 * @param ev Event loop
840 * @param fd File descriptor of socket
841 * @return 0 on success, non-0 on error
843 int ev_listen_cancel(ev_source *ev, int fd) {
844 D(("cancelling listener fd %d", fd));
845 return ev_fd_cancel(ev, ev_read, fd);
848 /* buffer *********************************************************************/
850 /** @brief Buffer structure */
852 char *base, *start, *end, *top;
855 /* @brief Make sure there is @p bytes available at @c b->end */
856 static void buffer_space(struct buffer *b, size_t bytes) {
857 D(("buffer_space %p %p %p %p want %lu",
858 (void *)b->base, (void *)b->start, (void *)b->end, (void *)b->top,
859 (unsigned long)bytes));
860 if(b->start == b->end)
861 b->start = b->end = b->base;
862 if((size_t)(b->top - b->end) < bytes) {
863 if((size_t)((b->top - b->end) + (b->start - b->base)) < bytes) {
864 size_t newspace = b->end - b->start + bytes, n;
867 for(n = 16; n < newspace; n *= 2)
869 newbase = xmalloc_noptr(n);
870 memcpy(newbase, b->start, b->end - b->start);
872 b->end = newbase + (b->end - b->start);
873 b->top = newbase + n;
874 b->start = newbase; /* must be last */
876 memmove(b->base, b->start, b->end - b->start);
877 b->end = b->base + (b->end - b->start);
881 D(("result %p %p %p %p",
882 (void *)b->base, (void *)b->start, (void *)b->end, (void *)b->top));
885 /* buffered writer ************************************************************/
887 /** @brief State structure for a buffered writer */
893 ev_error_callback *callback;
898 /** @brief Called when a writer's file descriptor is writable */
899 static int writer_callback(ev_source *ev, int fd, void *u) {
903 n = write(fd, w->b.start, w->b.end - w->b.start);
904 D(("callback for writer fd %d, %ld bytes, n=%d, errno=%d",
905 fd, (long)(w->b.end - w->b.start), n, errno));
908 if(w->b.start == w->b.end) {
910 ev_fd_cancel(ev, ev_write, fd);
911 return w->callback(ev, fd, 0, w->u);
913 ev_fd_disable(ev, ev_write, fd);
921 ev_fd_cancel(ev, ev_write, fd);
922 return w->callback(ev, fd, errno, w->u);
928 /** @brief Write bytes to a writer's buffer
930 * This is the sink write callback.
932 * Calls ev_fd_enable() if necessary (i.e. if the buffer was empty but
935 static int ev_writer_write(struct sink *sk, const void *s, int n) {
936 ev_writer *w = (ev_writer *)sk;
938 buffer_space(&w->b, n);
939 if(w->b.start == w->b.end)
940 ev_fd_enable(w->ev, ev_write, w->fd);
941 memcpy(w->b.end, s, n);
946 /** @brief Create a new buffered writer
947 * @param ev Event loop
948 * @param fd File descriptor to write to
949 * @param callback Called if an error occurs and when finished
950 * @param u Passed to @p callback
951 * @param what Text description
952 * @return New writer or @c NULL
954 ev_writer *ev_writer_new(ev_source *ev,
956 ev_error_callback *callback,
959 ev_writer *w = xmalloc(sizeof *w);
961 D(("registering writer fd %d callback %p %p", fd, (void *)callback, u));
962 w->s.write = ev_writer_write;
964 w->callback = callback;
967 if(ev_fd(ev, ev_write, fd, writer_callback, w, what))
969 ev_fd_disable(ev, ev_write, fd);
973 /** @brief Return the sink associated with a writer
975 * @return Pointer to sink
977 * Writing to the sink will arrange for those bytes to be written to the file
978 * descriptor as and when it is writable.
980 struct sink *ev_writer_sink(ev_writer *w) {
984 /** @brief Shutdown callback
986 * See ev_writer_close().
988 static int writer_shutdown(ev_source *ev,
989 const attribute((unused)) struct timeval *now,
993 return w->callback(ev, w->fd, 0, w->u);
996 /** @brief Close a writer
997 * @param w Writer to close
998 * @return 0 on success, non-0 on error
1000 * Close a writer. No more bytes should be written to its sink.
1002 * When the last byte has been written the callback will be called with an
1003 * error code of 0. It is guaranteed that this will NOT happen before
1004 * ev_writer_close() returns (although the file descriptor for the writer might
1005 * be cancelled by the time it returns).
1007 int ev_writer_close(ev_writer *w) {
1008 D(("close writer fd %d", w->fd));
1010 if(w->b.start == w->b.end) {
1011 /* we're already finished */
1012 ev_fd_cancel(w->ev, ev_write, w->fd);
1013 return ev_timeout(w->ev, 0, 0, writer_shutdown, w);
1018 /** @brief Cancel a writer discarding any buffered data
1019 * @param w Writer to close
1020 * @return 0 on success, non-0 on error
1022 * This cancels a writer immediately. Any unwritten buffered data is discarded
1023 * and the error callback is never called. This is appropriate to call if (for
1024 * instance) the read half of a TCP connection is known to have failed and the
1025 * writer is therefore obsolete.
1027 int ev_writer_cancel(ev_writer *w) {
1028 D(("cancel writer fd %d", w->fd));
1029 return ev_fd_cancel(w->ev, ev_write, w->fd);
1032 /** @brief Attempt to flush a writer
1033 * @param w Writer to flush
1034 * @return 0 on success, non-0 on error
1036 * Does a speculative write of any buffered data. Does not block if it cannot
1039 int ev_writer_flush(ev_writer *w) {
1040 return writer_callback(w->ev, w->fd, w);
1043 /* buffered reader ************************************************************/
1045 /** @brief State structure for a buffered reader */
1049 ev_reader_callback *callback;
1050 ev_error_callback *error_callback;
1056 /** @brief Called when a reader's @p fd is readable */
1057 static int reader_callback(ev_source *ev, int fd, void *u) {
1061 buffer_space(&r->b, 1);
1062 n = read(fd, r->b.end, r->b.top - r->b.end);
1063 D(("read fd %d buffer %d returned %d errno %d",
1064 fd, (int)(r->b.top - r->b.end), n, errno));
1067 return r->callback(ev, r, fd, r->b.start, r->b.end - r->b.start, 0, r->u);
1070 ev_fd_cancel(ev, ev_read, fd);
1071 return r->callback(ev, r, fd, r->b.start, r->b.end - r->b.start, 1, r->u);
1078 ev_fd_cancel(ev, ev_read, fd);
1079 return r->error_callback(ev, fd, errno, r->u);
1085 /** @brief Create a new buffered reader
1086 * @param ev Event loop
1087 * @param fd File descriptor to read from
1088 * @param callback Called when new data is available
1089 * @param error_callback Called if an error occurs
1090 * @param u Passed to callbacks
1091 * @param what Text description
1092 * @return New reader or @c NULL
1094 ev_reader *ev_reader_new(ev_source *ev,
1096 ev_reader_callback *callback,
1097 ev_error_callback *error_callback,
1100 ev_reader *r = xmalloc(sizeof *r);
1102 D(("registering reader fd %d callback %p %p %p",
1103 fd, (void *)callback, (void *)error_callback, u));
1105 r->callback = callback;
1106 r->error_callback = error_callback;
1109 if(ev_fd(ev, ev_read, fd, reader_callback, r, what))
1114 void ev_reader_buffer(ev_reader *r, size_t nbytes) {
1115 buffer_space(&r->b, nbytes - (r->b.end - r->b.start));
1118 /** @brief Consume @p n bytes from the reader's buffer
1120 * @param n Number of bytes to consume
1122 * Tells the reader than the next @p n bytes have been dealt with and can now
1125 void ev_reader_consume(ev_reader *r, size_t n) {
1129 /** @brief Cancel a reader
1131 * @return 0 on success, non-0 on error
1133 int ev_reader_cancel(ev_reader *r) {
1134 D(("cancel reader fd %d", r->fd));
1135 return ev_fd_cancel(r->ev, ev_read, r->fd);
1138 /** @brief Temporarily disable a reader
1140 * @return 0 on success, non-0 on error
1142 * No further callbacks for this reader will be made. Re-enable with
1143 * ev_reader_enable().
1145 int ev_reader_disable(ev_reader *r) {
1146 D(("disable reader fd %d", r->fd));
1147 return r->eof ? 0 : ev_fd_disable(r->ev, ev_read, r->fd);
1150 /** @brief Called from ev_run() for ev_reader_incomplete() */
1151 static int reader_continuation(ev_source attribute((unused)) *ev,
1152 const attribute((unused)) struct timeval *now,
1156 D(("reader continuation callback fd %d", r->fd));
1157 if(ev_fd_enable(r->ev, ev_read, r->fd)) return -1;
1158 return r->callback(ev, r, r->fd, r->b.start, r->b.end - r->b.start, r->eof, r->u);
1161 /** @brief Arrange another callback
1163 * @return 0 on success, non-0 on error
1165 * Indicates that the reader can process more input but would like to yield to
1166 * other clients of the event loop. Input will be disabled but it will be
1167 * re-enabled on the next iteration of the event loop and the read callback
1168 * will be called again (even if no further bytes are available).
1170 int ev_reader_incomplete(ev_reader *r) {
1171 if(ev_fd_disable(r->ev, ev_read, r->fd)) return -1;
1172 return ev_timeout(r->ev, 0, 0, reader_continuation, r);
1175 static int reader_enabled(ev_source *ev,
1176 const attribute((unused)) struct timeval *now,
1180 D(("reader enabled callback fd %d", r->fd));
1181 return r->callback(ev, r, r->fd, r->b.start, r->b.end - r->b.start, r->eof, r->u);
1184 /** @brief Re-enable reading
1186 * @return 0 on success, non-0 on error
1188 * If there is unconsumed data then you get a callback next time round the
1189 * event loop even if nothing new has been read.
1191 * The idea is in your read callback you come across a line (or whatever) that
1192 * can't be processed immediately. So you set up processing and disable
1193 * reading with ev_reader_disable(). Later when you finish processing you
1194 * re-enable. You'll automatically get another callback directly from the
1195 * event loop (i.e. not from inside ev_reader_enable()) so you can handle the
1196 * next line (or whatever) if the whole thing has in fact already arrived.
1198 int ev_reader_enable(ev_reader *r) {
1199 D(("enable reader fd %d", r->fd));
1200 return ((r->eof ? 0 : ev_fd_enable(r->ev, ev_read, r->fd))
1201 || ev_timeout(r->ev, 0, 0, reader_enabled, r)) ? -1 : 0;