diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/bus.c | 41 | ||||
| -rw-r--r-- | src/bus.h | 23 |
2 files changed, 44 insertions, 20 deletions
@@ -745,14 +745,25 @@ done: * misbehave, is `bus_poll` is written to expect * this function to have been called. * - * @param bus Bus information - * @return 0 on success, -1 on error + * @param bus Bus information + * @param flags `IPC_NOWAIT` if the bus should fail and set `errno` to + * `EAGAIN` if there isn't already a message available on + * the bus when `bus_poll` is called + * @return 0 on success, -1 on error */ int -bus_poll_start(bus_t *bus) +bus_poll_start(bus_t *bus, int flags) { bus->first_poll = 1; - return release_semaphore(bus, S, SEM_UNDO); + bus->flags = flags; + t(release_semaphore(bus, S, SEM_UNDO)); + if (flags & BUS_NOWAIT) { + t(release_semaphore(bus, Q, 0)); + } + return 0; + +fail: + return -1; } @@ -779,29 +790,35 @@ bus_poll_stop(const bus_t *bus) * started, the caller of this function should then * either call `bus_poll` again or `bus_poll_stop`. * - * @param bus Bus information - * @param flags `IPC_NOWAIT` if the bus should fail and set `errno` to - * `EAGAIN` if this isn't already a message available on the bus - * @return The received message, `NULL` on error + * @param bus Bus information + * @return The received message, `NULL` on error */ const char * -bus_poll(bus_t *bus, int flags) +bus_poll(bus_t *bus) { int state = 0, saved_errno; - (void) flags; if (!bus->first_poll) { t(release_semaphore(bus, W, SEM_UNDO)); state++; t(acquire_semaphore(bus, S, SEM_UNDO)); state++; t(zero_semaphore(bus, S, 0)); +#ifndef BUS_SEMAPHORES_ARE_SYNCHRONOUS_ME_HARDER t(zero_semaphore(bus, N, 0)); +#endif t(release_semaphore(bus, S, SEM_UNDO)); state--; t(acquire_semaphore(bus, W, SEM_UNDO)); state--; + if (bus->flags & BUS_NOWAIT) { + t(release_semaphore(bus, Q, 0)); + } } else { bus->first_poll = 0; } state--; - t(release_semaphore(bus, Q, 0)); - t(zero_semaphore(bus, Q, F(BUS_NOWAIT, IPC_NOWAIT))); + if (bus->flags & BUS_NOWAIT) { + t(zero_semaphore(bus, Q, IPC_NOWAIT)); + } else { + t(release_semaphore(bus, Q, 0)); + t(zero_semaphore(bus, Q, 0)); + } return bus->message; fail: @@ -105,6 +105,12 @@ typedef struct bus * if `bus_poll` failed during reading */ int first_poll; + + /** + * Flags used for polling + */ + int flags; + } bus_t; @@ -199,10 +205,13 @@ int bus_read(const bus_t *bus, int (*callback)(const char *message, void *user_d * misbehave, is `bus_poll` is written to expect * this function to have been called. * - * @param bus Bus information - * @return 0 on success, -1 on error + * @param bus Bus information + * @param flags `IPC_NOWAIT` if the bus should fail and set `errno` to + * `EAGAIN` if there isn't already a message available on + * the bus when `bus_poll` is called + * @return 0 on success, -1 on error */ -int bus_poll_start(bus_t *bus); +int bus_poll_start(bus_t *bus, int flags); /** * Announce that the thread has stopped listening on the bus. @@ -222,12 +231,10 @@ int bus_poll_stop(const bus_t *bus); * started, the caller of this function should then * either call `bus_poll` again or `bus_poll_stop`. * - * @param bus Bus information - * @param flags `IPC_NOWAIT` if the bus should fail and set `errno` to - * `EAGAIN` if this isn't already a message available on the bus - * @return The received message, `NULL` on error + * @param bus Bus information + * @return The received message, `NULL` on error */ -const char *bus_poll(bus_t *bus, int flags); +const char *bus_poll(bus_t *bus); /* TODO bus_poll_timed */ |