1 /* Licensed under LGPLv2.1+ - see LICENSE file for details */
4 #include <ccan/tal/tal.h>
5 #include <ccan/typesafe_cb/typesafe_cb.h>
15 * struct io_plan - a plan for input or output.
17 * Each io_conn has zero to two of these active at any time.
22 * struct io_conn - a connection associated with an fd.
27 * io_new_conn - create a new connection.
28 * @ctx: the context to tal from (or NULL)
29 * @fd: the file descriptor.
30 * @init: the function to call for a new connection
31 * @arg: the argument to @init.
33 * This creates a connection which owns @fd, it then calls
34 * @init to initialize the connection, which sets up an io_plan.
36 * Returns NULL on error (and sets errno).
39 * // Dumb init function to print string and tell conn to close.
40 * static struct io_plan *conn_init(struct io_conn *conn, const char *msg)
42 * printf("Created conn %p: %s", conn, msg);
43 * return io_close(conn);
46 * static void create_self_closing_pipe(void)
49 * struct io_conn *conn;
53 * conn = io_new_conn(NULL, fd[0], conn_init, (const char *)"hi!");
58 #define io_new_conn(ctx, fd, init, arg) \
59 io_new_conn_((ctx), (fd), \
60 typesafe_cb_preargs(struct io_plan *, void *, \
62 struct io_conn *conn), \
65 struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
66 struct io_plan *(*init)(struct io_conn *, void *),
70 * io_set_finish - set finish function on a connection.
71 * @conn: the connection.
72 * @finish: the function to call when it's closed or fails.
73 * @arg: the argument to @finish.
75 * @finish will be called when an I/O operation fails, or you call
76 * io_close() on the connection. errno will be set to the value
77 * after the failed I/O, or at the call to io_close(). The fd
78 * will be closed before @finish is called.
81 * static void finish(struct io_conn *conn, const char *msg)
83 * // errno is not 0 after success, so this is a bit useless.
84 * printf("Conn %p closed with errno %i (%s)\n", conn, errno, msg);
87 * // Dumb init function to print string and tell conn to close.
88 * static struct io_plan *conn_init(struct io_conn *conn, const char *msg)
90 * io_set_finish(conn, finish, msg);
91 * return io_close(conn);
94 #define io_set_finish(conn, finish, arg) \
95 io_set_finish_((conn), \
96 typesafe_cb_preargs(void, void *, \
100 void io_set_finish_(struct io_conn *conn,
101 void (*finish)(struct io_conn *, void *),
106 * io_new_listener - create a new accepting listener.
107 * @ctx: the context to tal from (or NULL)
108 * @fd: the file descriptor.
109 * @init: the function to call for a new connection
110 * @arg: the argument to @init.
112 * When @fd becomes readable, we accept(), create a new connection,
113 * (tal'ocated off @ctx) and pass that to init(). Note that if there is
114 * an error on this file descriptor, it will be freed.
116 * Returns NULL on error (and sets errno).
119 * #include <sys/types.h>
120 * #include <sys/socket.h>
125 * // Set up a listening socket, return it.
126 * static struct io_listener *do_listen(const char *port)
128 * struct addrinfo *addrinfo, hints;
131 * memset(&hints, 0, sizeof(hints));
132 * hints.ai_family = AF_UNSPEC;
133 * hints.ai_socktype = SOCK_STREAM;
134 * hints.ai_flags = AI_PASSIVE;
135 * hints.ai_protocol = 0;
137 * if (getaddrinfo(NULL, port, &hints, &addrinfo) != 0)
140 * fd = socket(addrinfo->ai_family, addrinfo->ai_socktype,
141 * addrinfo->ai_protocol);
145 * freeaddrinfo(addrinfo);
146 * setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
147 * if (bind(fd, addrinfo->ai_addr, addrinfo->ai_addrlen) != 0) {
151 * if (listen(fd, 1) != 0) {
155 * return io_new_listener(NULL, fd, conn_init, (const char *)"listened!");
158 #define io_new_listener(ctx, fd, init, arg) \
159 io_new_listener_((ctx), (fd), \
160 typesafe_cb_preargs(struct io_plan *, void *, \
162 struct io_conn *conn), \
164 struct io_listener *io_new_listener_(const tal_t *ctx, int fd,
165 struct io_plan *(*init)(struct io_conn *,
170 * io_close_listener - delete a listener.
171 * @listener: the listener returned from io_new_listener.
173 * This closes the fd and frees @listener.
177 * struct io_listener *l = do_listen("8111");
179 * io_loop(NULL, NULL);
180 * io_close_listener(l);
183 void io_close_listener(struct io_listener *listener);
186 * io_write - output plan to write data.
187 * @conn: the connection that plan is for.
188 * @data: the data buffer.
189 * @len: the length to write.
190 * @next: function to call output is done.
191 * @arg: @next argument
193 * This updates the output plan, to write out a data buffer. Once it's all
194 * written, the @next function will be called: on an error, the finish
195 * function is called instead.
197 * Note that the I/O may actually be done immediately.
200 * static struct io_plan *write_to_conn(struct io_conn *conn, const char *msg)
202 * // Write message, then close.
203 * return io_write(conn, msg, strlen(msg), io_close_cb, NULL);
206 #define io_write(conn, data, len, next, arg) \
207 io_write_((conn), (data), (len), \
208 typesafe_cb_preargs(struct io_plan *, void *, \
209 (next), (arg), struct io_conn *), \
211 struct io_plan *io_write_(struct io_conn *conn,
212 const void *data, size_t len,
213 struct io_plan *(*next)(struct io_conn *, void *),
217 * io_read - input plan to read data.
218 * @conn: the connection that plan is for.
219 * @data: the data buffer.
220 * @len: the length to read.
221 * @next: function to call once input is done.
222 * @arg: @next argument
224 * This creates a plan to read data into a buffer. Once it's all
225 * read, the @next function will be called: on an error, the finish
226 * function is called instead.
228 * Note that the I/O may actually be done immediately.
231 * static struct io_plan *read_from_conn(struct io_conn *conn, char *buf)
233 * // Read message, then close.
234 * return io_read(conn, buf, 12, io_close_cb, NULL);
237 #define io_read(conn, data, len, next, arg) \
238 io_read_((conn), (data), (len), \
239 typesafe_cb_preargs(struct io_plan *, void *, \
240 (next), (arg), struct io_conn *), \
242 struct io_plan *io_read_(struct io_conn *conn,
243 void *data, size_t len,
244 struct io_plan *(*next)(struct io_conn *, void *),
249 * io_read_partial - input plan to read some data.
250 * @conn: the connection that plan is for.
251 * @data: the data buffer.
252 * @maxlen: the maximum length to read
253 * @lenp: set to the length actually read.
254 * @next: function to call once input is done.
255 * @arg: @next argument
257 * This creates a plan to read data into a buffer. Once any data is
258 * read, @len is updated and the @next function will be called: on an
259 * error, the finish function is called instead.
261 * Note that the I/O may actually be done immediately.
269 * static struct io_plan *dump(struct io_conn *conn, struct buf *b)
271 * printf("Partial read: '%*s'\n", (int)b->len, b->buf);
273 * return io_close(conn);
276 * static struct io_plan *read_part(struct io_conn *conn, struct buf *b)
278 * // Read message, then dump and close.
279 * return io_read_partial(conn, b->buf, sizeof(b->buf), &b->len, dump, b);
282 #define io_read_partial(conn, data, maxlen, lenp, next, arg) \
283 io_read_partial_((conn), (data), (maxlen), (lenp), \
284 typesafe_cb_preargs(struct io_plan *, void *, \
288 struct io_plan *io_read_partial_(struct io_conn *conn,
289 void *data, size_t maxlen, size_t *lenp,
290 struct io_plan *(*next)(struct io_conn *,
295 * io_write_partial - output plan to write some data.
296 * @conn: the connection that plan is for.
297 * @data: the data buffer.
298 * @maxlen: the maximum length to write
299 * @lenp: set to the length actually written.
300 * @next: function to call once output is done.
301 * @arg: @next argument
303 * This creates a plan to write data from a buffer. Once any data is
304 * written, @len is updated and the @next function will be called: on an
305 * error, the finish function is called instead.
307 * Note that the I/O may actually be done immediately.
315 * static struct io_plan *show_partial(struct io_conn *conn, struct buf *b)
317 * printf("Only wrote: '%*s'\n", (int)b->len, b->buf);
319 * return io_close(conn);
322 * static struct io_plan *write_part(struct io_conn *conn, struct buf *b)
324 * // Write message, then dump and close.
325 * strcpy(b->buf, "Hello world");
326 * return io_write_partial(conn, b->buf, strlen(b->buf),
327 * &b->len, show_partial, b);
330 #define io_write_partial(conn, data, maxlen, lenp, next, arg) \
331 io_write_partial_((conn), (data), (maxlen), (lenp), \
332 typesafe_cb_preargs(struct io_plan *, void *, \
336 struct io_plan *io_write_partial_(struct io_conn *conn,
337 const void *data, size_t maxlen, size_t *lenp,
338 struct io_plan *(*next)(struct io_conn *,
343 * io_always - plan to immediately call next callback
344 * @conn: the connection that plan is for.
345 * @next: function to call.
346 * @arg: @next argument
348 * Sometimes it's neater to plan a callback rather than call it directly;
349 * for example, if you only need to read data for one path and not another.
352 * static struct io_plan *init_conn_with_nothing(struct io_conn *conn,
355 * // Silly example: close on next time around loop.
356 * return io_always(conn, io_close_cb, NULL);
359 #define io_always(conn, next, arg) \
360 io_always_((conn), typesafe_cb_preargs(struct io_plan *, void *, \
365 struct io_plan *io_always_(struct io_conn *conn,
366 struct io_plan *(*next)(struct io_conn *, void *),
370 * io_out_always - output plan to immediately call next callback
371 * @conn: the connection that plan is for.
372 * @next: function to call.
373 * @arg: @next argument
375 * This is a variant of io_always() which uses the output plan; it only
376 * matters if you are using io_duplex, and thus have two plans running at
379 #define io_out_always(conn, next, arg) \
380 io_out_always_((conn), typesafe_cb_preargs(struct io_plan *, void *, \
385 struct io_plan *io_out_always_(struct io_conn *conn,
386 struct io_plan *(*next)(struct io_conn *,
391 * io_connect - create an asynchronous connection to a listening socket.
392 * @conn: the connection that plan is for.
393 * @addr: where to connect.
394 * @init: function to call once it's connected
395 * @arg: @init argument
397 * This initiates a connection, and creates a plan for
398 * (asynchronously) completing it. Once complete, the @init function
402 * #include <sys/types.h>
403 * #include <sys/socket.h>
406 * // Write, then close socket.
407 * static struct io_plan *init_connect(struct io_conn *conn,
408 * struct addrinfo *addrinfo)
410 * return io_connect(conn, addrinfo, io_close_cb, NULL);
416 * struct addrinfo *addrinfo;
418 * fd = socket(AF_INET, SOCK_STREAM, 0);
419 * getaddrinfo("localhost", "8111", NULL, &addrinfo);
420 * io_new_conn(NULL, fd, init_connect, addrinfo);
423 #define io_connect(conn, addr, next, arg) \
424 io_connect_((conn), (addr), \
425 typesafe_cb_preargs(struct io_plan *, void *, \
430 struct io_plan *io_connect_(struct io_conn *conn, const struct addrinfo *addr,
431 struct io_plan *(*next)(struct io_conn *, void *),
435 * io_duplex - set plans for both input and output.
436 * @conn: the connection that plan is for.
437 * @in: the input plan
438 * @out: the output plan
440 * Most plans are either for input or output; io_duplex creates a plan
441 * which does both. This is often used in the init function to create
442 * two independent streams, though it can be used once on any connection.
444 * Note that if either plan closes the connection, it will be closed.
452 * static struct io_plan *read_and_write(struct io_conn *conn, struct buf *b)
454 * return io_duplex(conn,
455 * io_read(conn, b->in, sizeof(b->in), io_close_cb, b),
456 * io_write(conn, b->out, sizeof(b->out), io_close_cb,b));
459 struct io_plan *io_duplex(struct io_conn *conn,
460 struct io_plan *in_plan, struct io_plan *out_plan);
463 * io_halfclose - close half of an io_duplex connection.
464 * @conn: the connection that plan is for.
466 * It's common to want to close a duplex connection after both input and
467 * output plans have completed. If either calls io_close() the connection
468 * closes immediately. Instead, io_halfclose() needs to be called twice.
476 * static struct io_plan *finish(struct io_conn *conn, struct buf *b)
478 * return io_halfclose(conn);
481 * static struct io_plan *read_and_write(struct io_conn *conn, struct buf *b)
483 * return io_duplex(conn,
484 * io_read(conn, b->in, sizeof(b->in), finish, b),
485 * io_write(conn, b->out, sizeof(b->out), finish, b));
488 struct io_plan *io_halfclose(struct io_conn *conn);
491 * io_wait - leave a plan idle until something wakes us.
492 * @conn: the connection that plan is for.
493 * @waitaddr: the address to wait on.
494 * @next: function to call after waiting.
495 * @arg: @next argument
497 * This leaves the input or output idle: io_wake(@waitaddr) will be
498 * called later to restart the connection.
501 * // Silly example to wait then close.
502 * static struct io_plan *wait(struct io_conn *conn, void *b)
504 * return io_wait(conn, b, io_close_cb, NULL);
507 #define io_wait(conn, waitaddr, next, arg) \
508 io_wait_((conn), (waitaddr), \
509 typesafe_cb_preargs(struct io_plan *, void *, \
514 struct io_plan *io_wait_(struct io_conn *conn,
516 struct io_plan *(*next)(struct io_conn *, void *),
521 * io_out_wait - leave the output plan idle until something wakes us.
522 * @conn: the connection that plan is for.
523 * @waitaddr: the address to wait on.
524 * @next: function to call after waiting.
525 * @arg: @next argument
527 * io_wait() makes the input plan idle: if you're not using io_duplex it
528 * doesn't matter which plan is waiting. Otherwise, you may need to use
529 * io_out_wait() instead, to specify explicitly that the output plan is
532 #define io_out_wait(conn, waitaddr, next, arg) \
533 io_out_wait_((conn), (waitaddr), \
534 typesafe_cb_preargs(struct io_plan *, void *, \
539 struct io_plan *io_out_wait_(struct io_conn *conn,
541 struct io_plan *(*next)(struct io_conn *, void *),
545 * io_wake - wake up any connections waiting on @wait
546 * @waitaddr: the address to trigger.
548 * All io_conns who have returned io_wait() on @waitaddr will move on
549 * to their next callback.
552 * static struct io_plan *wake_it(struct io_conn *conn, void *b)
555 * return io_close(conn);
558 void io_wake(const void *wait);
561 * io_break - return from io_loop()
562 * @ret: non-NULL value to return from io_loop().
564 * This breaks out of the io_loop. As soon as the current function
565 * returns, any io_close()'d connections will have their finish
566 * callbacks called, then io_loop() with return with @ret.
568 * If io_loop() is called again, then @plan will be carried out.
571 * static struct io_plan *fail_on_timeout(struct io_conn *conn, char *msg)
574 * return io_close(conn);
577 void io_break(const void *ret);
580 * io_never - assert if callback is called.
581 * @conn: the connection that plan is for.
582 * @unused: an unused parameter to make this suitable for use as a callback.
584 * Sometimes you want to make it clear that a callback should never happen
585 * (eg. for io_break). This will assert() if called.
588 * static struct io_plan *break_out(struct io_conn *conn, void *unused)
591 * // We won't ever return from io_break
592 * return io_never(conn, NULL);
595 struct io_plan *io_never(struct io_conn *conn, void *unused);
597 /* FIXME: io_recvfrom/io_sendto */
600 * io_close - close a connection.
601 * @conn: the connection to close.
603 * The connection is immediately freed: it doesn't have to be the
604 * current connection and it doesn't need to be idle. No more IO or
605 * callbacks will occur, but if a function was added by io_set_finish()
606 * it will be called with the current errno preserved.
608 * This is equivalent to tal_free(io_conn), except it returns an io_plan
609 * for use in an io callback.
612 * static struct io_plan *close_on_timeout(struct io_conn *conn, const char *msg)
614 * printf("closing: %s\n", msg);
615 * return io_close(conn);
618 struct io_plan *io_close(struct io_conn *conn);
621 * io_close_cb - helper callback to close a connection.
622 * @conn: the connection.
624 * This is closes a connection; designed to be used as a callback
628 * #define close_on_timeout io_close_cb
630 struct io_plan *io_close_cb(struct io_conn *, void *unused);
633 * io_close_taken_fd - close a connection, but remove the filedescriptor first.
634 * @conn: the connection to take the file descriptor from and close.
636 * io_close closes the file descriptor underlying the io_conn; this version does
637 * not. Presumably you have used io_conn_fd() on it beforehand and will take
638 * care of the fd yourself.
640 * Note that this also turns off O_NONBLOCK on the fd.
643 * static struct io_plan *steal_fd(struct io_conn *conn, int *fd)
645 * *fd = io_conn_fd(conn);
646 * printf("stealing fd %i and closing\n", *fd);
647 * return io_close_taken_fd(conn);
650 struct io_plan *io_close_taken_fd(struct io_conn *conn);
653 * io_loop - process fds until all closed on io_break.
654 * @timers - timers which are waiting to go off (or NULL for none)
655 * @expired - an expired timer (can be NULL if @timers is)
657 * This is the core loop; it exits with the io_break() arg, or NULL if
658 * all connections and listeners are closed, or with @expired set to an
659 * expired timer (if @timers isn't NULL).
662 * io_loop(NULL, NULL);
664 void *io_loop(struct timers *timers, struct timer **expired);
667 * io_conn_fd - get the fd from a connection.
668 * @conn: the connection.
670 * Sometimes useful, eg for getsockname(). Note that the fd is O_NONBLOCK.
675 int io_conn_fd(const struct io_conn *conn);
678 * io_flush_sync - (synchronously) complete any outstanding output.
679 * @conn: the connection.
681 * This is generally used as an emergency escape, for example when we
682 * want to write an error message on a socket before terminating, but it may
683 * be in the middle of existing I/O. We don't want to service any other
686 * This returns true if all pending output is complete, false on error.
687 * The next callback is not called on the conn, but will be as soon as
688 * io_loop() is called.
693 bool io_flush_sync(struct io_conn *conn);
696 * io_fd_block - helper to set an fd blocking/nonblocking.
697 * @fd: the file descriptor
698 * @block: true to set blocking, false to set non-blocking.
700 * Generally only fails is @fd isn't a valid file descriptor, otherwise
703 bool io_fd_block(int fd, bool block);
706 * io_time_override - override the normal call for time.
707 * @nowfn: the function to call.
709 * io usually uses time_mono() internally, but this forces it
710 * to use your function (eg. for debugging). Returns the old
713 struct timemono (*io_time_override(struct timemono (*now)(void)))(void);
716 * io_poll_override - override the normal call for poll.
717 * @pollfn: the function to call.
719 * io usually uses poll() internally, but this forces it to use your
720 * function (eg. for debugging, suppressing fds, or polling on others unknown
721 * to ccan/io). Returns the old one.
723 int (*io_poll_override(int (*poll)(struct pollfd *fds, nfds_t nfds, int timeout)))(struct pollfd *, nfds_t, int);
725 #endif /* CCAN_IO_H */