/* Licensed under LGPLv2.1+ - see LICENSE file for details */ #ifndef CCAN_IO_H #define CCAN_IO_H #include #include #include #include struct timers; struct timer; struct list_head; /** * struct io_plan - a plan for input or output. * * Each io_conn has zero to two of these active at any time. */ struct io_plan; /** * struct io_conn - a connection associated with an fd. */ struct io_conn; /** * io_new_conn - create a new connection. * @ctx: the context to tal from (or NULL) * @fd: the file descriptor. * @init: the function to call for a new connection * @arg: the argument to @init. * * This creates a connection which owns @fd, it then calls * @init to initialize the connection, which sets up an io_plan. * * Returns NULL on error (and sets errno). * * Example: * // Dumb init function to print string and tell conn to close. * static struct io_plan *conn_init(struct io_conn *conn, const char *msg) * { * printf("Created conn %p: %s", conn, msg); * return io_close(conn); * } * * static void create_self_closing_pipe(void) * { * int fd[2]; * struct io_conn *conn; * * pipe(fd); * conn = io_new_conn(NULL, fd[0], conn_init, (const char *)"hi!"); * if (!conn) * exit(1); * } */ #define io_new_conn(ctx, fd, init, arg) \ io_new_conn_((ctx), (fd), \ typesafe_cb_preargs(struct io_plan *, void *, \ (init), (arg), \ struct io_conn *conn), \ (void *)(arg)) struct io_conn *io_new_conn_(const tal_t *ctx, int fd, struct io_plan *(*init)(struct io_conn *, void *), void *arg); /** * io_set_finish - set finish function on a connection. * @conn: the connection. * @finish: the function to call when it's closed or fails. * @arg: the argument to @finish. * * @finish will be called when an I/O operation fails, or you call * io_close() on the connection. errno will be set to the value * after the failed I/O, or at the call to io_close(). The fd * will be closed before @finish is called. * * Example: * static void finish(struct io_conn *conn, const char *msg) * { * // errno is not 0 after success, so this is a bit useless. * printf("Conn %p closed with errno %i (%s)\n", conn, errno, msg); * } * * // Dumb init function to print string and tell conn to close. * static struct io_plan *conn_init(struct io_conn *conn, const char *msg) * { * io_set_finish(conn, finish, msg); * return io_close(conn); * } */ #define io_set_finish(conn, finish, arg) \ io_set_finish_((conn), \ typesafe_cb_preargs(void, void *, \ (finish), (arg), \ struct io_conn *), \ (void *)(arg)) void io_set_finish_(struct io_conn *conn, void (*finish)(struct io_conn *, void *), void *arg); /** * io_new_listener - create a new accepting listener. * @ctx: the context to tal from (or NULL) * @fd: the file descriptor. * @init: the function to call for a new connection * @arg: the argument to @init. * * When @fd becomes readable, we accept(), create a new connection, * (tal'ocated off @ctx) and pass that to init(). * * Returns NULL on error (and sets errno). * * Example: * #include * #include * #include * * ... * * // Set up a listening socket, return it. * static struct io_listener *do_listen(const char *port) * { * struct addrinfo *addrinfo, hints; * int fd, on = 1; * * memset(&hints, 0, sizeof(hints)); * hints.ai_family = AF_UNSPEC; * hints.ai_socktype = SOCK_STREAM; * hints.ai_flags = AI_PASSIVE; * hints.ai_protocol = 0; * * if (getaddrinfo(NULL, port, &hints, &addrinfo) != 0) * return NULL; * * fd = socket(addrinfo->ai_family, addrinfo->ai_socktype, * addrinfo->ai_protocol); * if (fd < 0) * return NULL; * * freeaddrinfo(addrinfo); * setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); * if (bind(fd, addrinfo->ai_addr, addrinfo->ai_addrlen) != 0) { * close(fd); * return NULL; * } * if (listen(fd, 1) != 0) { * close(fd); * return NULL; * } * return io_new_listener(NULL, fd, conn_init, (const char *)"listened!"); * } */ #define io_new_listener(ctx, fd, init, arg) \ io_new_listener_((ctx), (fd), \ typesafe_cb_preargs(struct io_plan *, void *, \ (init), (arg), \ struct io_conn *conn), \ (void *)(arg)) struct io_listener *io_new_listener_(const tal_t *ctx, int fd, struct io_plan *(*init)(struct io_conn *, void *), void *arg); /** * io_close_listener - delete a listener. * @listener: the listener returned from io_new_listener. * * This closes the fd and frees @listener. * * Example: * ... * struct io_listener *l = do_listen("8111"); * if (l) { * io_loop(NULL, NULL); * io_close_listener(l); * } */ void io_close_listener(struct io_listener *listener); /** * io_write - output plan to write data. * @conn: the connection that plan is for. * @data: the data buffer. * @len: the length to write. * @next: function to call output is done. * @arg: @next argument * * This updates the output plan, to write out a data buffer. Once it's all * written, the @next function will be called: on an error, the finish * function is called instead. * * Note that the I/O may actually be done immediately. * * Example: * static struct io_plan *write_to_conn(struct io_conn *conn, const char *msg) * { * // Write message, then close. * return io_write(conn, msg, strlen(msg), io_close_cb, NULL); * } */ #define io_write(conn, data, len, next, arg) \ io_write_((conn), (data), (len), \ typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), struct io_conn *), \ (arg)) struct io_plan *io_write_(struct io_conn *conn, const void *data, size_t len, struct io_plan *(*next)(struct io_conn *, void *), void *arg); /** * io_read - input plan to read data. * @conn: the connection that plan is for. * @data: the data buffer. * @len: the length to read. * @next: function to call once input is done. * @arg: @next argument * * This creates a plan to read data into a buffer. Once it's all * read, the @next function will be called: on an error, the finish * function is called instead. * * Note that the I/O may actually be done immediately. * * Example: * static struct io_plan *read_from_conn(struct io_conn *conn, char *buf) * { * // Read message, then close. * return io_read(conn, buf, 12, io_close_cb, NULL); * } */ #define io_read(conn, data, len, next, arg) \ io_read_((conn), (data), (len), \ typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), struct io_conn *), \ (arg)) struct io_plan *io_read_(struct io_conn *conn, void *data, size_t len, struct io_plan *(*next)(struct io_conn *, void *), void *arg); /** * io_read_partial - input plan to read some data. * @conn: the connection that plan is for. * @data: the data buffer. * @maxlen: the maximum length to read * @lenp: set to the length actually read. * @next: function to call once input is done. * @arg: @next argument * * This creates a plan to read data into a buffer. Once any data is * read, @len is updated and the @next function will be called: on an * error, the finish function is called instead. * * Note that the I/O may actually be done immediately. * * Example: * struct buf { * size_t len; * char buf[12]; * }; * * static struct io_plan *dump(struct io_conn *conn, struct buf *b) * { * printf("Partial read: '%*s'\n", (int)b->len, b->buf); * free(b); * return io_close(conn); * } * * static struct io_plan *read_part(struct io_conn *conn, struct buf *b) * { * // Read message, then dump and close. * return io_read_partial(conn, b->buf, sizeof(b->buf), &b->len, dump, b); * } */ #define io_read_partial(conn, data, maxlen, lenp, next, arg) \ io_read_partial_((conn), (data), (maxlen), (lenp), \ typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), \ struct io_conn *), \ (arg)) struct io_plan *io_read_partial_(struct io_conn *conn, void *data, size_t maxlen, size_t *lenp, struct io_plan *(*next)(struct io_conn *, void *), void *arg); /** * io_write_partial - output plan to write some data. * @conn: the connection that plan is for. * @data: the data buffer. * @maxlen: the maximum length to write * @lenp: set to the length actually written. * @next: function to call once output is done. * @arg: @next argument * * This creates a plan to write data from a buffer. Once any data is * written, @len is updated and the @next function will be called: on an * error, the finish function is called instead. * * Note that the I/O may actually be done immediately. * * Example: * struct buf { * size_t len; * char buf[12]; * }; * * static struct io_plan *show_partial(struct io_conn *conn, struct buf *b) * { * printf("Only wrote: '%*s'\n", (int)b->len, b->buf); * free(b); * return io_close(conn); * } * * static struct io_plan *write_part(struct io_conn *conn, struct buf *b) * { * // Write message, then dump and close. * strcpy(b->buf, "Hello world"); * return io_write_partial(conn, b->buf, strlen(b->buf), * &b->len, show_partial, b); * } */ #define io_write_partial(conn, data, maxlen, lenp, next, arg) \ io_write_partial_((conn), (data), (maxlen), (lenp), \ typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), \ struct io_conn *), \ (arg)) struct io_plan *io_write_partial_(struct io_conn *conn, const void *data, size_t maxlen, size_t *lenp, struct io_plan *(*next)(struct io_conn *, void*), void *arg); /** * io_always - plan to immediately call next callback * @conn: the connection that plan is for. * @next: function to call. * @arg: @next argument * * Sometimes it's neater to plan a callback rather than call it directly; * for example, if you only need to read data for one path and not another. * * Example: * static struct io_plan *init_conn_with_nothing(struct io_conn *conn, * void *unused) * { * // Silly example: close on next time around loop. * return io_always(conn, io_close_cb, NULL); * } */ #define io_always(conn, next, arg) \ io_always_((conn), typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), \ struct io_conn *), \ (arg)) struct io_plan *io_always_(struct io_conn *conn, struct io_plan *(*next)(struct io_conn *, void *), void *arg); /** * io_out_always - output plan to immediately call next callback * @conn: the connection that plan is for. * @next: function to call. * @arg: @next argument * * This is a variant of io_always() which uses the output plan; it only * matters if you are using io_duplex, and thus have two plans running at * once. */ #define io_out_always(conn, next, arg) \ io_out_always_((conn), typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), \ struct io_conn *), \ (arg)) struct io_plan *io_out_always_(struct io_conn *conn, struct io_plan *(*next)(struct io_conn *, void *), void *arg); /** * io_connect - create an asynchronous connection to a listening socket. * @conn: the connection that plan is for. * @addr: where to connect. * @init: function to call once it's connected * @arg: @init argument * * This initiates a connection, and creates a plan for * (asynchronously) completing it. Once complete, the @init function * will be called. * * Example: * #include * #include * #include * * // Write, then close socket. * static struct io_plan *init_connect(struct io_conn *conn, * struct addrinfo *addrinfo) * { * return io_connect(conn, addrinfo, io_close_cb, NULL); * } * * ... * * int fd; * struct addrinfo *addrinfo; * * fd = socket(AF_INET, SOCK_STREAM, 0); * getaddrinfo("localhost", "8111", NULL, &addrinfo); * io_new_conn(NULL, fd, init_connect, addrinfo); */ struct addrinfo; #define io_connect(conn, addr, next, arg) \ io_connect_((conn), (addr), \ typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), \ struct io_conn *), \ (arg)) struct io_plan *io_connect_(struct io_conn *conn, const struct addrinfo *addr, struct io_plan *(*next)(struct io_conn *, void *), void *arg); /** * io_duplex - set plans for both input and output. * @conn: the connection that plan is for. * @in: the input plan * @out: the output plan * * Most plans are either for input or output; io_duplex creates a plan * which does both. This is often used in the init function to create * two independent streams, though it can be used once on any connection. * * Note that if either plan closes the connection, it will be closed. * * Example: * struct buf { * char in[100]; * char out[100]; * }; * * static struct io_plan *read_and_write(struct io_conn *conn, struct buf *b) * { * return io_duplex(conn, * io_read(conn, b->in, sizeof(b->in), io_close_cb, b), * io_write(conn, b->out, sizeof(b->out), io_close_cb,b)); * } */ #define io_duplex(conn, in_plan, out_plan) \ (io_duplex_prepare(conn), io_duplex_(in_plan, out_plan)) struct io_plan *io_duplex_(struct io_plan *in_plan, struct io_plan *out_plan); void io_duplex_prepare(struct io_conn *conn); /** * io_halfclose - close half of an io_duplex connection. * @conn: the connection that plan is for. * * It's common to want to close a duplex connection after both input and * output plans have completed. If either calls io_close() the connection * closes immediately. Instead, io_halfclose() needs to be called twice. * * Example: * struct buf { * char in[100]; * char out[100]; * }; * * static struct io_plan *finish(struct io_conn *conn, struct buf *b) * { * return io_halfclose(conn); * } * * static struct io_plan *read_and_write(struct io_conn *conn, struct buf *b) * { * return io_duplex(conn, * io_read(conn, b->in, sizeof(b->in), finish, b), * io_write(conn, b->out, sizeof(b->out), finish, b)); * } */ struct io_plan *io_halfclose(struct io_conn *conn); /** * io_wait - leave a plan idle until something wakes us. * @conn: the connection that plan is for. * @waitaddr: the address to wait on. * @next: function to call after waiting. * @arg: @next argument * * This leaves the input or output idle: io_wake(@waitaddr) will be * called later to restart the connection. * * Example: * // Silly example to wait then close. * static struct io_plan *wait(struct io_conn *conn, void *b) * { * return io_wait(conn, b, io_close_cb, NULL); * } */ #define io_wait(conn, waitaddr, next, arg) \ io_wait_((conn), (waitaddr), \ typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), \ struct io_conn *), \ (arg)) struct io_plan *io_wait_(struct io_conn *conn, const void *wait, struct io_plan *(*next)(struct io_conn *, void *), void *arg); /** * io_out_wait - leave the output plan idle until something wakes us. * @conn: the connection that plan is for. * @waitaddr: the address to wait on. * @next: function to call after waiting. * @arg: @next argument * * io_wait() makes the input plan idle: if you're not using io_duplex it * doesn't matter which plan is waiting. Otherwise, you may need to use * io_out_wait() instead, to specify explicitly that the output plan is * waiting. */ #define io_out_wait(conn, waitaddr, next, arg) \ io_out_wait_((conn), (waitaddr), \ typesafe_cb_preargs(struct io_plan *, void *, \ (next), (arg), \ struct io_conn *), \ (arg)) struct io_plan *io_out_wait_(struct io_conn *conn, const void *wait, struct io_plan *(*next)(struct io_conn *, void *), void *arg); /** * io_wake - wake up any connections waiting on @wait * @waitaddr: the address to trigger. * * All io_conns who have returned io_wait() on @waitaddr will move on * to their next callback. * * Example: * static struct io_plan *wake_it(struct io_conn *conn, void *b) * { * io_wake(b); * return io_close(conn); * } */ void io_wake(const void *wait); /** * io_break - return from io_loop() * @ret: non-NULL value to return from io_loop(). * * This breaks out of the io_loop. As soon as the current function * returns, any io_close()'d connections will have their finish * callbacks called, then io_loop() with return with @ret. * * If io_loop() is called again, then @plan will be carried out. * * Example: * static struct io_plan *fail_on_timeout(struct io_conn *conn, char *msg) * { * io_break(msg); * return io_close(conn); * } */ void io_break(const void *ret); /** * io_never - assert if callback is called. * @conn: the connection that plan is for. * @unused: an unused parameter to make this suitable for use as a callback. * * Sometimes you want to make it clear that a callback should never happen * (eg. for io_break). This will assert() if called. * * Example: * static struct io_plan *break_out(struct io_conn *conn, void *unused) * { * io_break(conn); * // We won't ever return from io_break * return io_never(conn, NULL); * } */ struct io_plan *io_never(struct io_conn *conn, void *unused); /* FIXME: io_recvfrom/io_sendto */ /** * io_close - plan to close a connection. * @conn: the connection to close. * * On return to io_loop, the connection will be closed. It doesn't have * to be the current connection and it doesn't need to be idle. No more * IO or callbacks will occur. * * You can close a connection twice without harmful effects. * * Example: * static struct io_plan *close_on_timeout(struct io_conn *conn, const char *msg) * { * printf("closing: %s\n", msg); * return io_close(conn); * } */ struct io_plan *io_close(struct io_conn *conn); /** * io_close_cb - helper callback to close a connection. * @conn: the connection. * * This schedules a connection to be closed; designed to be used as * a callback function. * * Example: * #define close_on_timeout io_close_cb */ struct io_plan *io_close_cb(struct io_conn *, void *unused); /** * io_loop - process fds until all closed on io_break. * @timers - timers which are waiting to go off (or NULL for none) * @expired - an expired timer (can be NULL if @timers is) * * This is the core loop; it exits with the io_break() arg, or NULL if * all connections and listeners are closed, or with @expired set to an * expired timer (if @timers isn't NULL). * * Example: * io_loop(NULL, NULL); */ void *io_loop(struct timers *timers, struct timer **expired); /** * io_conn_fd - get the fd from a connection. * @conn: the connection. * * Sometimes useful, eg for getsockname(). */ int io_conn_fd(const struct io_conn *conn); /** * io_set_debug - set synchronous mode on a connection. * @conn: the connection. * @debug: whether to enable or disable debug. * * Once @debug is true on a connection, all I/O is done synchronously * as soon as it is set, until it is unset or @conn is closed. This * makes it easy to debug what's happening with a connection, but note * that other connections are starved while this is being done. * * See also: io_debug_complete() * * Example: * // Dumb init function to set debug and tell conn to close. * static struct io_plan *conn_init(struct io_conn *conn, const char *msg) * { * io_set_debug(conn, true); * return io_close(conn); * } */ void io_set_debug(struct io_conn *conn, bool debug); /** * io_debug_complete - empty function called when conn is closing/waiting. * @conn: the connection. * * This is for putting a breakpoint onto, when debugging. It is called * when a conn with io_set_debug() true can no longer be synchronous: * 1) It is io_close()'d * 2) It enters io_wait() (sychronous debug will resume after io_wake()) * 3) io_break() is called (sychronous debug will resume after io_loop()) */ void io_debug_complete(struct io_conn *conn); #endif /* CCAN_IO_H */