diff options
Diffstat (limited to 'src/bus.c')
| -rw-r--r-- | src/bus.c | 154 |
1 files changed, 135 insertions, 19 deletions
@@ -33,6 +33,7 @@ #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> +#include <time.h> #include <sys/ipc.h> #include <sys/sem.h> @@ -422,6 +423,36 @@ mkdirs(char *pathname, mode_t mode) } +/** + * Convert an absolute time to a relative time + * + * @param delta Output parameter for the relative time + * @param absolute The absolute time + * @param clockid The ID of the clock the time is measured in + * @return 0 on success, -1 on error + */ +static int +absolute_time_to_delta_time(struct timespec *delta, const struct timespec *absolute, clockid_t clockid) +{ + if (clock_gettime(clockid, delta) < 0) + return -1; + + delta->tv_sec = absolute->tv_sec - delta->tv_sec; + delta->tv_nsec = absolute->tv_nsec - delta->tv_nsec; + + if (delta->tv_nsec < 0L) { + delta->tv_nsec += 1000000000L; + delta->tv_sec -= 1; + } + if (delta->tv_nsec >= 1000000000L) { + delta->tv_nsec -= 1000000000L; + delta->tv_sec += 1; + } + + return 0; +} + + /** * Create a new bus @@ -632,7 +663,7 @@ fail: /** - * Broadcast a message a bus + * Broadcast a message on a bus * * @param bus Bus information * @param message The message to write, may not be longer than @@ -677,26 +708,49 @@ fail: /** + * Broadcast a message on a bus + * + * @param bus Bus information + * @param message The message to write, may not be longer than + * `BUS_MEMORY_SIZE` including the NUL-termination + * @param timeout The time the operation shall fail with errno set + * to `EAGAIN` if not completed + * @param clockid The ID of the clock the `timeout` is measured with, + * it most be a predictable clock + * @return 0 on success, -1 on error + */ +int bus_write_timed(const bus_t *bus, const char *message, + const struct timespec *timeout, clockid_t clockid) +{ + /* TODO bus_write_timed */ + if (!timeout) + return bus_write(bus, message, 0); + (void) bus, (void) message, (void) timeout, (void) clockid; +} + + +/** * Listen (in a loop, forever) for new message on a bus * - * @param bus Bus information - * @param callback Function to call when a message is received, the - * input parameters will be the read message and - * `user_data` from `bus_read`'s parameter with the - * same name. The message must have been parsed or - * copied when `callback` returns as it may be over - * overridden after that time. `callback` should - * return either of the the values: - * * 0: stop listening - * * 1: continue listening - * * -1: an error has occurred - * However, the function [`bus_read`] will invoke - * `callback` with `message` set to `NULL`one time - * directly after it has started listening on the - * bus. This is to the the program now it can safely - * continue with any action that requires that the - * programs is listening on the bus. - * @return 0 on success, -1 on error + * @param bus Bus information + * @param callback Function to call when a message is received, the + * input parameters will be the read message and + * `user_data` from `bus_read`'s parameter with the + * same name. The message must have been parsed or + * copied when `callback` returns as it may be over + * overridden after that time. `callback` should + * return either of the the values: + * * 0: stop listening + * * 1: continue listening + * * -1: an error has occurred + * However, the function [`bus_read`] will invoke + * `callback` with `message` set to `NULL`one time + * directly after it has started listening on the + * bus. This is to the the program now it can safely + * continue with any action that requires that the + * programs is listening on the bus. + * @param user_data Parameter passed to `callback` + * @return 0 on success, -1 on error */ int bus_read(const bus_t *bus, int (*callback)(const char *message, void *user_data), void *user_data) @@ -738,6 +792,44 @@ done: /** + * Listen (in a loop, forever) for new message on a bus + * + * @param bus Bus information + * @param callback Function to call when a message is received, the + * input parameters will be the read message and + * `user_data` from `bus_read`'s parameter with the + * same name. The message must have been parsed or + * copied when `callback` returns as it may be over + * overridden after that time. `callback` should + * return either of the the values: + * * 0: stop listening + * * 1: continue listening + * * -1: an error has occurred + * However, the function [`bus_read`] will invoke + * `callback` with `message` set to `NULL`one time + * directly after it has started listening on the + * bus. This is to the the program now it can safely + * continue with any action that requires that the + * programs is listening on the bus. + * @param user_data Parameter passed to `callback` + * @param timeout The time the operation shall fail with errno set + * to `EAGAIN` if not completed, note that the callback + * function may or may not have been called + * @param clockid The ID of the clock the `timeout` is measured with, + * it most be a predictable clock + * @return 0 on success, -1 on error + */ +int bus_read_timed(const bus_t *bus, int (*callback)(const char *message, void *user_data), + void *user_data, const struct timespec *timeout, clockid_t clockid) +{ + /* TODO bus_read_timed */ + if (!timeout) + return bus_read(bus, callback, user_data); + (void) bus, (void) callback, (void) user_data, (void) timeout, (void) clockid; +} + + +/** * Announce that the thread is listening on the bus. * This is required so the will does not miss any * messages due to race conditions. Additionally, @@ -835,6 +927,30 @@ fail: /** + * Wait for a message to be broadcasted on the bus. + * The caller should make a copy of the received message, + * without freeing the original copy, and parse it in a + * separate thread. When the new thread has started be + * started, the caller of this function should then + * either call `bus_poll_timed` again or `bus_poll_stop`. + * + * @param bus Bus information + * @param timeout The time the operation shall fail with errno set + * to `EAGAIN` if not completed + * @param clockid The ID of the clock the `timeout` is measured with, + * it most be a predictable clock + * @return The received message, `NULL` on error + */ +const char *bus_poll_timed(bus_t *bus, const struct timespec *timeout, clockid_t clockid) +{ + /* TODO bus_poll_timed */ + if (!timeout) + return bus_poll(bus); + (void) bus, (void) timeout, (void) clockid; +} + + +/** * Change the ownership of a bus * * `stat(2)` can be used of the bus's associated file to get the bus's ownership |