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
);
409 /* Suppress any pending callbacks */
414 /** @brief Log a report of file descriptor state */
415 void ev_report(ev_source
*ev
) {
422 for(mode
= 0; mode
< ev_nmodes
; ++mode
) {
423 info("mode %s maxfd %d", modenames
[mode
], ev
->mode
[mode
].maxfd
);
424 for(n
= 0; n
< ev
->mode
[mode
].nfds
; ++n
) {
425 fd
= ev
->mode
[mode
].fds
[n
].fd
;
426 info("fd %s %d%s%s (%s)", modenames
[mode
], fd
,
427 FD_ISSET(fd
, &ev
->mode
[mode
].enabled
) ?
" enabled" : "",
428 FD_ISSET(fd
, &ev
->mode
[mode
].tripped
) ?
" tripped" : "",
429 ev
->mode
[mode
].fds
[n
].what
);
432 for(fd
= 0; fd
<= ev
->mode
[mode
].maxfd
; ++fd
) {
433 if(!FD_ISSET(fd
, &ev
->mode
[mode
].enabled
))
435 for(n
= 0; n
< ev
->mode
[mode
].nfds
; ++n
) {
436 if(ev
->mode
[mode
].fds
[n
].fd
== fd
)
439 if(n
< ev
->mode
[mode
].nfds
)
440 snprintf(b
, sizeof b
, "%d(%s)", fd
, ev
->mode
[mode
].fds
[n
].what
);
442 snprintf(b
, sizeof b
, "%d", fd
);
443 dynstr_append(d
, ' ');
444 dynstr_append_string(d
, b
);
447 info("%s enabled:%s", modenames
[mode
], d
->vec
);
451 /* timeouts *******************************************************************/
453 /** @brief Register a timeout
454 * @param ev Event source
455 * @param handle Where to store timeout handle, or @c NULL
456 * @param when Earliest time to call @p callback, or @c NULL
457 * @param callback Function to call at or after @p when
458 * @param u Passed to @p callback
459 * @return 0 on success, non-0 on error
461 * If @p when is a null pointer then a time of 0 is assumed. The effect is to
462 * call the timeout handler from ev_run() next time around the event loop.
463 * This is used internally to schedule various operations if it is not
464 * convenient to call them from the current place in the call stack, or
465 * externally to ensure that other clients of the event loop get a look in when
466 * performing some lengthy operation.
468 int ev_timeout(ev_source
*ev
,
469 ev_timeout_handle
*handlep
,
470 const struct timeval
*when
,
471 ev_timeout_callback
*callback
,
473 struct timeout
*t
, *p
, **pp
;
475 D(("registering timeout at %ld.%ld callback %p %p",
476 when ?
(long)when
->tv_sec
: 0, when ?
(long)when
->tv_usec
: 0,
477 (void *)callback
, u
));
478 t
= xmalloc(sizeof *t
);
481 t
->callback
= callback
;
484 while((p
= *pp
) && gt(&t
->when
, &p
->when
))
493 /** @brief Cancel a timeout
494 * @param ev Event loop
495 * @param handle Handle returned from ev_timeout(), or 0
496 * @return 0 on success, non-0 on error
498 * If @p handle is 0 then this is a no-op.
500 int ev_timeout_cancel(ev_source
*ev
,
501 ev_timeout_handle handle
) {
502 struct timeout
*t
= handle
, *p
, **pp
;
506 for(pp
= &ev
->timeouts
; (p
= *pp
) && p
!= t
; pp
= &p
->next
)
515 /* signals ********************************************************************/
517 /** @brief Mapping of signals to pipe write ends
519 * The pipes are per-event loop, it's possible in theory for there to be
520 * multiple event loops (e.g. in different threads), although in fact DisOrder
523 static int sigfd
[NSIG
];
525 /** @brief The signal handler
526 * @param s Signal number
528 * Writes to @c sigfd[s].
530 static void sighandler(int s
) {
531 unsigned char sc
= s
;
532 static const char errmsg
[] = "error writing to signal pipe";
534 /* probably the reader has stopped listening for some reason */
535 if(write(sigfd
[s
], &sc
, 1) < 0) {
536 write(2, errmsg
, sizeof errmsg
- 1);
541 /** @brief Read callback for signals */
542 static int signal_read(ev_source
*ev
,
543 int attribute((unused
)) fd
,
544 void attribute((unused
)) *u
) {
549 if((n
= read(ev
->sigpipe
[0], &s
, 1)) == 1)
550 if((ret
= ev
->signals
[s
].callback(ev
, s
, ev
->signals
[s
].u
)))
553 if(n
< 0 && (errno
!= EINTR
&& errno
!= EAGAIN
)) {
554 error(errno
, "error reading from signal pipe %d", ev
->sigpipe
[0]);
560 /** @brief Close the signal pipe */
561 static void close_sigpipe(ev_source
*ev
) {
562 int save_errno
= errno
;
564 xclose(ev
->sigpipe
[0]);
565 xclose(ev
->sigpipe
[1]);
566 ev
->sigpipe
[0] = ev
->sigpipe
[1] = -1;
570 /** @brief Register a signal handler
571 * @param ev Event loop
572 * @param sig Signal to handle
573 * @param callback Called when signal is delivered
574 * @param u Passed to @p callback
575 * @return 0 on success, non-0 on error
577 * Note that @p callback is called from inside ev_run(), not from inside the
578 * signal handler, so the usual restrictions on signal handlers do not apply.
580 int ev_signal(ev_source
*ev
,
582 ev_signal_callback
*callback
,
587 D(("registering signal %d handler callback %p %p", sig
, (void *)callback
, u
));
590 assert(sig
<= UCHAR_MAX
);
591 if(ev
->sigpipe
[0] == -1) {
592 D(("creating signal pipe"));
594 D(("signal pipe is %d, %d", ev
->sigpipe
[0], ev
->sigpipe
[1]));
595 for(n
= 0; n
< 2; ++n
) {
596 nonblock(ev
->sigpipe
[n
]);
597 cloexec(ev
->sigpipe
[n
]);
599 if(ev_fd(ev
, ev_read
, ev
->sigpipe
[0], signal_read
, 0, "sigpipe read")) {
604 sigaddset(&ev
->sigmask
, sig
);
605 xsigprocmask(SIG_BLOCK
, &ev
->sigmask
, 0);
606 sigfd
[sig
] = ev
->sigpipe
[1];
607 ev
->signals
[sig
].callback
= callback
;
608 ev
->signals
[sig
].u
= u
;
609 sa
.sa_handler
= sighandler
;
610 sigfillset(&sa
.sa_mask
);
611 sa
.sa_flags
= SA_RESTART
;
612 xsigaction(sig
, &sa
, &ev
->signals
[sig
].oldsa
);
617 /** @brief Cancel a signal handler
618 * @param ev Event loop
619 * @param sig Signal to cancel
620 * @return 0 on success, non-0 on error
622 int ev_signal_cancel(ev_source
*ev
,
626 xsigaction(sig
, &ev
->signals
[sig
].oldsa
, 0);
627 ev
->signals
[sig
].callback
= 0;
629 sigdelset(&ev
->sigmask
, sig
);
632 xsigprocmask(SIG_UNBLOCK
, &ss
, 0);
636 /** @brief Clean up signal handling
637 * @param ev Event loop
639 * This function can be called from inside a fork. It restores signal
640 * handlers, unblocks the signals, and closes the signal pipe for @p ev.
642 void ev_signal_atfork(ev_source
*ev
) {
645 if(ev
->sigpipe
[0] != -1) {
646 /* revert any handled signals to their original state */
647 for(sig
= 1; sig
< NSIG
; ++sig
) {
648 if(ev
->signals
[sig
].callback
!= 0)
649 xsigaction(sig
, &ev
->signals
[sig
].oldsa
, 0);
651 /* and then unblock them */
652 xsigprocmask(SIG_UNBLOCK
, &ev
->sigmask
, 0);
653 /* don't want a copy of the signal pipe open inside the fork */
654 xclose(ev
->sigpipe
[0]);
655 xclose(ev
->sigpipe
[1]);
659 /* child processes ************************************************************/
661 /** @brief Called on SIGCHLD */
662 static int sigchld_callback(ev_source
*ev
,
663 int attribute((unused
)) sig
,
664 void attribute((unused
)) *u
) {
667 int status
, n
, ret
, revisit
;
671 for(n
= 0; n
< ev
->nchildren
; ++n
) {
672 r
= wait4(ev
->children
[n
].pid
,
674 ev
->children
[n
].options
| WNOHANG
,
677 ev_child_callback
*c
= ev
->children
[n
].callback
;
678 void *cu
= ev
->children
[n
].u
;
680 if(WIFEXITED(status
) || WIFSIGNALED(status
))
681 ev_child_cancel(ev
, r
);
683 if((ret
= c(ev
, r
, status
, &ru
, cu
)))
686 /* We should "never" get an ECHILD but it can in fact happen. For
687 * instance on Linux 2.4.31, and probably other versions, if someone
688 * straces a child process and then a different child process
689 * terminates, when we wait4() the trace process we will get ECHILD
690 * because it has been reparented to strace. Obviously this is a
691 * hopeless design flaw in the tracing infrastructure, but we don't
692 * want the disorder server to bomb out because of it. So we just log
693 * the problem and ignore it.
695 error(errno
, "error calling wait4 for PID %lu (broken ptrace?)",
696 (unsigned long)ev
->children
[n
].pid
);
705 /** @brief Configure event loop for child process handling
706 * @return 0 on success, non-0 on error
708 * Currently at most one event loop can handle child processes and it must be
709 * distinguished from others by calling this function on it. This could be
710 * fixed but since no process ever makes use of more than one event loop there
713 int ev_child_setup(ev_source
*ev
) {
714 D(("installing SIGCHLD handler"));
715 return ev_signal(ev
, SIGCHLD
, sigchld_callback
, 0);
718 /** @brief Wait for a child process to terminate
719 * @param ev Event loop
720 * @param pid Process ID of child
721 * @param options Options to pass to @c wait4()
722 * @param callback Called when child terminates (or possibly when it stops)
723 * @param u Passed to @p callback
724 * @return 0 on success, non-0 on error
726 * You must have called ev_child_setup() on @p ev once first.
728 int ev_child(ev_source
*ev
,
731 ev_child_callback
*callback
,
735 D(("registering child handling %ld options %d callback %p %p",
736 (long)pid
, options
, (void *)callback
, u
));
737 assert(ev
->signals
[SIGCHLD
].callback
== sigchld_callback
);
738 if(ev
->nchildren
>= ev
->nchildslots
) {
739 ev
->nchildslots
= ev
->nchildslots ?
2 * ev
->nchildslots
: 16;
740 ev
->children
= xrealloc(ev
->children
,
741 ev
->nchildslots
* sizeof (struct child
));
744 ev
->children
[n
].pid
= pid
;
745 ev
->children
[n
].options
= options
;
746 ev
->children
[n
].callback
= callback
;
747 ev
->children
[n
].u
= u
;
751 /** @brief Stop waiting for a child process
752 * @param ev Event loop
753 * @param pid Child process ID
754 * @return 0 on success, non-0 on error
756 int ev_child_cancel(ev_source
*ev
,
760 for(n
= 0; n
< ev
->nchildren
&& ev
->children
[n
].pid
!= pid
; ++n
)
762 assert(n
< ev
->nchildren
);
763 if(n
!= ev
->nchildren
- 1)
764 ev
->children
[n
] = ev
->children
[ev
->nchildren
- 1];
769 /* socket listeners ***********************************************************/
771 /** @brief State for a socket listener */
772 struct listen_state
{
773 ev_listen_callback
*callback
;
777 /** @brief Called when a listenign socket is readable */
778 static int listen_callback(ev_source
*ev
, int fd
, void *u
) {
779 const struct listen_state
*l
= u
;
782 struct sockaddr_in in
;
783 #if HAVE_STRUCT_SOCKADDR_IN6
784 struct sockaddr_in6 in6
;
786 struct sockaddr_un un
;
792 D(("callback for listener fd %d", fd
));
793 while((addrlen
= sizeof addr
),
794 (newfd
= accept(fd
, &addr
.sa
, &addrlen
)) >= 0) {
795 if((ret
= l
->callback(ev
, newfd
, &addr
.sa
, addrlen
, l
->u
)))
804 error(errno
, "error calling accept");
809 /* XXX on some systems EPROTO should be fatal, but we don't know if
810 * we're running on one of them */
811 error(errno
, "error calling accept");
815 fatal(errno
, "error calling accept");
818 if(errno
!= EINTR
&& errno
!= EAGAIN
)
819 error(errno
, "error calling accept");
823 /** @brief Listen on a socket for inbound stream connections
824 * @param ev Event source
825 * @param fd File descriptor of socket
826 * @param callback Called when a new connection arrives
827 * @param u Passed to @p callback
828 * @param what Text description of socket
829 * @return 0 on success, non-0 on error
831 int ev_listen(ev_source
*ev
,
833 ev_listen_callback
*callback
,
836 struct listen_state
*l
= xmalloc(sizeof *l
);
838 D(("registering listener fd %d callback %p %p", fd
, (void *)callback
, u
));
839 l
->callback
= callback
;
841 return ev_fd(ev
, ev_read
, fd
, listen_callback
, l
, what
);
844 /** @brief Stop listening on a socket
845 * @param ev Event loop
846 * @param fd File descriptor of socket
847 * @return 0 on success, non-0 on error
849 int ev_listen_cancel(ev_source
*ev
, int fd
) {
850 D(("cancelling listener fd %d", fd
));
851 return ev_fd_cancel(ev
, ev_read
, fd
);
854 /* buffer *********************************************************************/
856 /** @brief Buffer structure */
858 char *base
, *start
, *end
, *top
;
861 /* @brief Make sure there is @p bytes available at @c b->end */
862 static void buffer_space(struct buffer
*b
, size_t bytes
) {
863 D(("buffer_space %p %p %p %p want %lu",
864 (void *)b
->base
, (void *)b
->start
, (void *)b
->end
, (void *)b
->top
,
865 (unsigned long)bytes
));
866 if(b
->start
== b
->end
)
867 b
->start
= b
->end
= b
->base
;
868 if((size_t)(b
->top
- b
->end
) < bytes
) {
869 if((size_t)((b
->top
- b
->end
) + (b
->start
- b
->base
)) < bytes
) {
870 size_t newspace
= b
->end
- b
->start
+ bytes
, n
;
873 for(n
= 16; n
< newspace
; n
*= 2)
875 newbase
= xmalloc_noptr(n
);
876 memcpy(newbase
, b
->start
, b
->end
- b
->start
);
878 b
->end
= newbase
+ (b
->end
- b
->start
);
879 b
->top
= newbase
+ n
;
880 b
->start
= newbase
; /* must be last */
882 memmove(b
->base
, b
->start
, b
->end
- b
->start
);
883 b
->end
= b
->base
+ (b
->end
- b
->start
);
887 D(("result %p %p %p %p",
888 (void *)b
->base
, (void *)b
->start
, (void *)b
->end
, (void *)b
->top
));
891 /* readers and writers *******************************************************/
893 /** @brief State structure for a buffered writer */
895 /** @brief Sink used for writing to the buffer */
898 /** @brief Output buffer */
901 /** @brief File descriptor to write to */
904 /** @brief Set if there'll be no more output */
907 /** @brief Error/termination callback */
908 ev_error_callback
*callback
;
910 /** @brief Passed to @p callback */
913 /** @brief Parent event source */
916 /** @brief Maximum amount of time between succesful writes, 0 = don't care */
918 /** @brief Maximum amount of data to buffer, 0 = don't care */
920 /** @brief Error code to pass to @p callback (see writer_shutdown()) */
922 /** @brief Timeout handle for @p timebound (or 0) */
923 ev_timeout_handle timeout
;
925 /** @brief Description of this writer */
928 /** @brief Tied reader or 0 */
932 /** @brief State structure for a buffered reader */
934 /** @brief Input buffer */
936 /** @brief File descriptor read from */
938 /** @brief Called when new data is available */
939 ev_reader_callback
*callback
;
940 /** @brief Called on error and shutdown */
941 ev_error_callback
*error_callback
;
942 /** @brief Passed to @p callback and @p error_callback */
944 /** @brief Parent event loop */
946 /** @brief Set when EOF is detected */
948 /** @brief Error code to pass to error callback */
950 /** @brief Tied writer or NULL */
954 /* buffered writer ************************************************************/
956 /** @brief Shut down the writer
958 * This is called to shut down a writer. The error callback is not called
959 * through any other path. Also we do not cancel @p fd from anywhere else,
960 * though we might disable it.
962 * It has the signature of a timeout callback so that it can be called from a
965 * Calls @p callback with @p w->syntherr as the error code (which might be 0).
967 static int writer_shutdown(ev_source
*ev
,
968 const attribute((unused
)) struct timeval
*now
,
973 return 0; /* already shut down */
974 info("writer_shutdown fd=%d", w
->fd
);
975 ev_timeout_cancel(ev
, w
->timeout
);
976 ev_fd_cancel(ev
, ev_write
, w
->fd
);
979 info("found a tied reader");
980 /* If there is a reader still around we just untie it */
981 w
->reader
->writer
= 0;
982 shutdown(w
->fd
, SHUT_WR
); /* there'll be no more writes */
984 info("no tied reader");
985 /* There's no reader so we are free to close the FD */
989 return w
->callback(ev
, w
->error
, w
->u
);
992 /** @brief Called when a writer's @p timebound expires */
993 static int writer_timebound_exceeded(ev_source
*ev
,
994 const struct timeval
*now
,
996 ev_writer
*const w
= u
;
998 error(0, "abandoning writer %s because no writes within %ds",
999 w
->what
, w
->timebound
);
1000 w
->error
= ETIMEDOUT
;
1001 return writer_shutdown(ev
, now
, u
);
1004 /** @brief Set the time bound callback (if not set already) */
1005 static void writer_set_timebound(ev_writer
*w
) {
1006 if(w
->timebound
&& !w
->timeout
) {
1007 struct timeval when
;
1008 ev_source
*const ev
= w
->ev
;
1010 xgettimeofday(&when
, 0);
1011 when
.tv_sec
+= w
->timebound
;
1012 ev_timeout(ev
, &w
->timeout
, &when
, writer_timebound_exceeded
, w
);
1016 /** @brief Called when a writer's file descriptor is writable */
1017 static int writer_callback(ev_source
*ev
, int fd
, void *u
) {
1018 ev_writer
*const w
= u
;
1021 n
= write(fd
, w
->b
.start
, w
->b
.end
- w
->b
.start
);
1022 D(("callback for writer fd %d, %ld bytes, n=%d, errno=%d",
1023 fd
, (long)(w
->b
.end
- w
->b
.start
), n
, errno
));
1025 /* Consume bytes from the buffer */
1027 /* Suppress any outstanding timeout */
1028 ev_timeout_cancel(ev
, w
->timeout
);
1030 if(w
->b
.start
== w
->b
.end
) {
1031 /* The buffer is empty */
1033 /* We're done, we can shut down this writer */
1035 return writer_shutdown(ev
, 0, w
);
1037 /* There might be more to come but we don't need writer_callback() to
1038 * be called for the time being */
1039 ev_fd_disable(ev
, ev_write
, fd
);
1041 /* The buffer isn't empty, set a timeout so we give up if we don't manage
1042 * to write some more within a reasonable time */
1043 writer_set_timebound(w
);
1051 return writer_shutdown(ev
, 0, w
);
1057 /** @brief Write bytes to a writer's buffer
1059 * This is the sink write callback.
1061 * Calls ev_fd_enable() if necessary (i.e. if the buffer was empty but
1064 static int ev_writer_write(struct sink
*sk
, const void *s
, int n
) {
1065 ev_writer
*w
= (ev_writer
*)sk
;
1068 return 0; /* avoid silliness */
1069 if(w
->spacebound
&& w
->b
.end
- w
->b
.start
+ n
> w
->spacebound
) {
1070 /* The new buffer contents will exceed the space bound. We assume that the
1071 * remote client has gone away and TCP hasn't noticed yet, or that it's got
1072 * hopelessly stuck. */
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
);
1077 return ev_timeout(w
->ev
, 0, 0, writer_shutdown
, w
);
1079 /* Make sure there is space */
1080 buffer_space(&w
->b
, n
);
1081 /* If the buffer was formerly empty then we'll need to re-enable the FD */
1082 if(w
->b
.start
== w
->b
.end
)
1083 ev_fd_enable(w
->ev
, ev_write
, w
->fd
);
1084 memcpy(w
->b
.end
, s
, n
);
1086 /* Arrange a timeout if there wasn't one set already */
1087 writer_set_timebound(w
);
1091 /** @brief Create a new buffered writer
1092 * @param ev Event loop
1093 * @param fd File descriptor to write to
1094 * @param callback Called if an error occurs and when finished
1095 * @param u Passed to @p callback
1096 * @param what Text description
1097 * @return New writer or @c NULL
1099 * Writers own their file descriptor and close it when they have finished with
1102 * If you pass the same fd to a reader and writer, you must tie them together
1105 ev_writer
*ev_writer_new(ev_source
*ev
,
1107 ev_error_callback
*callback
,
1110 ev_writer
*w
= xmalloc(sizeof *w
);
1112 D(("registering writer fd %d callback %p %p", fd
, (void *)callback
, u
));
1113 w
->s
.write
= ev_writer_write
;
1115 w
->callback
= callback
;
1118 w
->timebound
= 10 * 60;
1119 w
->spacebound
= 512 * 1024;
1121 if(ev_fd(ev
, ev_write
, fd
, writer_callback
, w
, what
))
1123 /* Buffer is initially empty so we don't want a callback */
1124 ev_fd_disable(ev
, ev_write
, fd
);
1128 /** @brief Get/set the time bound
1130 * @param new_time_bound New bound or -1 for no change
1131 * @return Latest time bound
1133 * If @p new_time_bound is negative then the current time bound is returned.
1134 * Otherwise it is set and the new value returned.
1136 * The time bound is the number of seconds allowed between writes. If it takes
1137 * longer than this to flush a buffer then the peer will be assumed to be dead
1138 * and an error will be synthesized. 0 means "don't care". The default time
1139 * bound is 10 minutes.
1141 * Note that this value does not take into account kernel buffering and
1144 int ev_writer_time_bound(ev_writer
*w
,
1145 int new_time_bound
) {
1146 if(new_time_bound
>= 0)
1147 w
->timebound
= new_time_bound
;
1148 return w
->timebound
;
1151 /** @brief Get/set the space bound
1153 * @param new_space_bound New bound or -1 for no change
1154 * @return Latest space bound
1156 * If @p new_space_bound is negative then the current space bound is returned.
1157 * Otherwise it is set and the new value returned.
1159 * The space bound is the number of bytes allowed between in the buffer. If
1160 * the buffer exceeds this size an error will be synthesized. 0 means "don't
1161 * care". The default space bound is 512Kbyte.
1163 * Note that this value does not take into account kernel buffering.
1165 int ev_writer_space_bound(ev_writer
*w
,
1166 int new_space_bound
) {
1167 if(new_space_bound
>= 0)
1168 w
->spacebound
= new_space_bound
;
1169 return w
->spacebound
;
1172 /** @brief Return the sink associated with a writer
1174 * @return Pointer to sink
1176 * Writing to the sink will arrange for those bytes to be written to the file
1177 * descriptor as and when it is writable.
1179 struct sink
*ev_writer_sink(ev_writer
*w
) {
1181 fatal(0, "ev_write_sink called with null writer");
1185 /** @brief Close a writer
1186 * @param w Writer to close
1187 * @return 0 on success, non-0 on error
1189 * Close a writer. No more bytes should be written to its sink.
1191 * When the last byte has been written the callback will be called with an
1192 * error code of 0. It is guaranteed that this will NOT happen before
1193 * ev_writer_close() returns (although the file descriptor for the writer might
1194 * be cancelled by the time it returns).
1196 int ev_writer_close(ev_writer
*w
) {
1197 D(("close writer fd %d", w
->fd
));
1199 return 0; /* already closed */
1201 if(w
->b
.start
== w
->b
.end
) {
1202 /* We're already finished */
1203 w
->error
= 0; /* no error */
1204 return ev_timeout(w
->ev
, 0, 0, writer_shutdown
, w
);
1209 /** @brief Attempt to flush a writer
1210 * @param w Writer to flush
1211 * @return 0 on success, non-0 on error
1213 * Does a speculative write of any buffered data. Does not block if it cannot
1216 int ev_writer_flush(ev_writer
*w
) {
1217 return writer_callback(w
->ev
, w
->fd
, w
);
1220 /* buffered reader ************************************************************/
1222 /** @brief Shut down a reader*
1224 * This is the only path through which we cancel and close the file descriptor.
1225 * As with the writer case it is given timeout signature to allow it be
1226 * deferred to the next iteration of the event loop.
1228 * We only call @p error_callback if @p error is nonzero (unlike the writer
1231 static int reader_shutdown(ev_source
*ev
,
1232 const attribute((unused
)) struct timeval
*now
,
1234 ev_reader
*const r
= u
;
1237 return 0; /* already shut down */
1238 info("reader_shutdown fd=%d", r
->fd
);
1239 ev_fd_cancel(ev
, ev_read
, r
->fd
);
1242 info("found a tied writer");
1243 /* If there is a writer still around we just untie it */
1244 r
->writer
->reader
= 0;
1245 shutdown(r
->fd
, SHUT_RD
); /* there'll be no more reads */
1247 info("no tied writer found");
1248 /* There's no writer so we are free to close the FD */
1253 return r
->error_callback(ev
, r
->error
, r
->u
);
1258 /** @brief Called when a reader's @p fd is readable */
1259 static int reader_callback(ev_source
*ev
, int fd
, void *u
) {
1263 buffer_space(&r
->b
, 1);
1264 n
= read(fd
, r
->b
.end
, r
->b
.top
- r
->b
.end
);
1265 D(("read fd %d buffer %d returned %d errno %d",
1266 fd
, (int)(r
->b
.top
- r
->b
.end
), n
, errno
));
1269 return r
->callback(ev
, r
, r
->b
.start
, r
->b
.end
- r
->b
.start
, 0, r
->u
);
1271 /* No more read callbacks needed */
1272 ev_fd_disable(r
->ev
, ev_read
, r
->fd
);
1273 ev_timeout(r
->ev
, 0, 0, reader_shutdown
, r
);
1274 /* Pass the remaining data and an eof indicator to the user */
1275 return r
->callback(ev
, r
, r
->b
.start
, r
->b
.end
- r
->b
.start
, 1, r
->u
);
1282 /* Fatal error, kill the reader now */
1284 return reader_shutdown(ev
, 0, r
);
1290 /** @brief Create a new buffered reader
1291 * @param ev Event loop
1292 * @param fd File descriptor to read from
1293 * @param callback Called when new data is available
1294 * @param error_callback Called if an error occurs
1295 * @param u Passed to callbacks
1296 * @param what Text description
1297 * @return New reader or @c NULL
1299 * Readers own their fd and close it when they are finished with it.
1301 * If you pass the same fd to a reader and writer, you must tie them together
1304 ev_reader
*ev_reader_new(ev_source
*ev
,
1306 ev_reader_callback
*callback
,
1307 ev_error_callback
*error_callback
,
1310 ev_reader
*r
= xmalloc(sizeof *r
);
1312 D(("registering reader fd %d callback %p %p %p",
1313 fd
, (void *)callback
, (void *)error_callback
, u
));
1315 r
->callback
= callback
;
1316 r
->error_callback
= error_callback
;
1319 if(ev_fd(ev
, ev_read
, fd
, reader_callback
, r
, what
))
1324 void ev_reader_buffer(ev_reader
*r
, size_t nbytes
) {
1325 buffer_space(&r
->b
, nbytes
- (r
->b
.end
- r
->b
.start
));
1328 /** @brief Consume @p n bytes from the reader's buffer
1330 * @param n Number of bytes to consume
1332 * Tells the reader than the next @p n bytes have been dealt with and can now
1335 void ev_reader_consume(ev_reader
*r
, size_t n
) {
1339 /** @brief Cancel a reader
1341 * @return 0 on success, non-0 on error
1343 * No further callbacks will be made, and the FD will be closed (in a later
1344 * iteration of the event loop).
1346 int ev_reader_cancel(ev_reader
*r
) {
1347 D(("cancel reader fd %d", r
->fd
));
1349 return 0; /* already thoroughly cancelled */
1350 ev_fd_disable(r
->ev
, ev_read
, r
->fd
);
1351 return ev_timeout(r
->ev
, 0, 0, reader_shutdown
, r
);
1354 /** @brief Temporarily disable a reader
1356 * @return 0 on success, non-0 on error
1358 * No further callbacks for this reader will be made. Re-enable with
1359 * ev_reader_enable().
1361 int ev_reader_disable(ev_reader
*r
) {
1362 D(("disable reader fd %d", r
->fd
));
1363 return ev_fd_disable(r
->ev
, ev_read
, r
->fd
);
1366 /** @brief Called from ev_run() for ev_reader_incomplete() */
1367 static int reader_continuation(ev_source
attribute((unused
)) *ev
,
1368 const attribute((unused
)) struct timeval
*now
,
1372 D(("reader continuation callback fd %d", r
->fd
));
1373 /* If not at EOF turn the FD back on */
1375 if(ev_fd_enable(r
->ev
, ev_read
, r
->fd
))
1377 /* We're already in a timeout callback so there's no reason we can't call the
1378 * user callback directly (compare ev_reader_enable()). */
1379 return r
->callback(ev
, r
, r
->b
.start
, r
->b
.end
- r
->b
.start
, r
->eof
, r
->u
);
1382 /** @brief Arrange another callback
1384 * @return 0 on success, non-0 on error
1386 * Indicates that the reader can process more input but would like to yield to
1387 * other clients of the event loop. Input will be disabled but it will be
1388 * re-enabled on the next iteration of the event loop and the read callback
1389 * will be called again (even if no further bytes are available).
1391 int ev_reader_incomplete(ev_reader
*r
) {
1392 if(ev_fd_disable(r
->ev
, ev_read
, r
->fd
)) return -1;
1393 return ev_timeout(r
->ev
, 0, 0, reader_continuation
, r
);
1396 static int reader_enabled(ev_source
*ev
,
1397 const attribute((unused
)) struct timeval
*now
,
1401 D(("reader enabled callback fd %d", r
->fd
));
1402 return r
->callback(ev
, r
, r
->b
.start
, r
->b
.end
- r
->b
.start
, r
->eof
, r
->u
);
1405 /** @brief Re-enable reading
1407 * @return 0 on success, non-0 on error
1409 * If there is unconsumed data then you get a callback next time round the
1410 * event loop even if nothing new has been read.
1412 * The idea is in your read callback you come across a line (or whatever) that
1413 * can't be processed immediately. So you set up processing and disable
1414 * reading with ev_reader_disable(). Later when you finish processing you
1415 * re-enable. You'll automatically get another callback directly from the
1416 * event loop (i.e. not from inside ev_reader_enable()) so you can handle the
1417 * next line (or whatever) if the whole thing has in fact already arrived.
1419 * The difference between this process and calling ev_reader_incomplete() is
1420 * ev_reader_incomplete() deals with the case where you can process now but
1421 * would rather yield to other clients of the event loop, while using
1422 * ev_reader_disable() and ev_reader_enable() deals with the case where you
1423 * cannot process input yet because some other process is actually not
1426 int ev_reader_enable(ev_reader
*r
) {
1427 D(("enable reader fd %d", r
->fd
));
1429 /* First if we're not at EOF then we re-enable reading */
1431 if(ev_fd_enable(r
->ev
, ev_read
, r
->fd
))
1433 /* Arrange another callback next time round the event loop */
1434 return ev_timeout(r
->ev
, 0, 0, reader_enabled
, r
);
1437 /** @brief Tie a reader and a writer together
1440 * @return 0 on success, non-0 on error
1442 * This function must be called if @p r and @p w share a file descritptor.
1444 int ev_tie(ev_reader
*r
, ev_writer
*w
) {
1445 assert(r
->writer
== 0);
1446 assert(w
->reader
== 0);