diff options
Diffstat (limited to 'sysdep/unix/io-loop.c')
| -rw-r--r-- | sysdep/unix/io-loop.c | 578 |
1 files changed, 578 insertions, 0 deletions
diff --git a/sysdep/unix/io-loop.c b/sysdep/unix/io-loop.c new file mode 100644 index 00000000..3e3fc31a --- /dev/null +++ b/sysdep/unix/io-loop.c @@ -0,0 +1,578 @@ +/* + * BIRD -- I/O and event loop + * + * Can be freely distributed and used under the terms of the GNU GPL. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> +#include <poll.h> +#include <pthread.h> +#include <time.h> +#include <sys/time.h> + +#include "nest/bird.h" + +#include "lib/buffer.h" +#include "lib/lists.h" +#include "lib/resource.h" +#include "lib/event.h" +#include "lib/timer.h" +#include "lib/socket.h" + +#include "lib/io-loop.h" +#include "sysdep/unix/io-loop.h" +#include "conf/conf.h" + +#define THREAD_STACK_SIZE 65536 /* To be lowered in near future */ + +/* + * Current thread context + */ + +_Thread_local struct birdloop *birdloop_current; +static _Thread_local struct birdloop *birdloop_wakeup_masked; +static _Thread_local uint birdloop_wakeup_masked_count; + +event_list * +birdloop_event_list(struct birdloop *loop) +{ + return &loop->event_list; +} + +struct timeloop * +birdloop_time_loop(struct birdloop *loop) +{ + return &loop->time; +} + +_Bool +birdloop_inside(struct birdloop *loop) +{ + for (struct birdloop *c = birdloop_current; c; c = c->prev_loop) + if (loop == c) + return 1; + + return 0; +} + +/* + * Wakeup code for birdloop + */ + +static void +pipe_new(int *pfds) +{ + int rv = pipe(pfds); + if (rv < 0) + die("pipe: %m"); + + if (fcntl(pfds[0], F_SETFL, O_NONBLOCK) < 0) + die("fcntl(O_NONBLOCK): %m"); + + if (fcntl(pfds[1], F_SETFL, O_NONBLOCK) < 0) + die("fcntl(O_NONBLOCK): %m"); +} + +void +pipe_drain(int fd) +{ + char buf[64]; + int rv; + + try: + rv = read(fd, buf, 64); + if (rv < 0) + { + if (errno == EINTR) + goto try; + if (errno == EAGAIN) + return; + die("wakeup read: %m"); + } + if (rv == 64) + goto try; +} + +void +pipe_kick(int fd) +{ + u64 v = 1; + int rv; + + try: + rv = write(fd, &v, sizeof(u64)); + if (rv < 0) + { + if (errno == EINTR) + goto try; + if (errno == EAGAIN) + return; + die("wakeup write: %m"); + } +} + +static inline void +wakeup_init(struct birdloop *loop) +{ + pipe_new(loop->wakeup_fds); +} + +static inline void +wakeup_drain(struct birdloop *loop) +{ + pipe_drain(loop->wakeup_fds[0]); +} + +static inline void +wakeup_do_kick(struct birdloop *loop) +{ + pipe_kick(loop->wakeup_fds[1]); +} + +static inline void +birdloop_do_ping(struct birdloop *loop) +{ + if (atomic_fetch_add_explicit(&loop->ping_sent, 1, memory_order_acq_rel)) + return; + + if (loop == birdloop_wakeup_masked) + birdloop_wakeup_masked_count++; + else + wakeup_do_kick(loop); +} + +void +birdloop_ping(struct birdloop *loop) +{ + if (birdloop_inside(loop) && !loop->ping_pending) + loop->ping_pending++; + else + birdloop_do_ping(loop); +} + + +/* + * Sockets + */ + +static void +sockets_init(struct birdloop *loop) +{ + init_list(&loop->sock_list); + loop->sock_num = 0; + + BUFFER_INIT(loop->poll_sk, loop->pool, 4); + BUFFER_INIT(loop->poll_fd, loop->pool, 4); + loop->poll_changed = 1; /* add wakeup fd */ +} + +static void +sockets_add(struct birdloop *loop, sock *s) +{ + add_tail(&loop->sock_list, &s->n); + loop->sock_num++; + + s->index = -1; + loop->poll_changed = 1; + + birdloop_ping(loop); +} + +void +sk_start(sock *s) +{ + ASSERT_DIE(birdloop_current != &main_birdloop); + sockets_add(birdloop_current, s); +} + +static void +sockets_remove(struct birdloop *loop, sock *s) +{ + rem_node(&s->n); + loop->sock_num--; + + if (s->index >= 0) + { + loop->poll_sk.data[s->index] = NULL; + s->index = -1; + loop->poll_changed = 1; + loop->close_scheduled = 1; + birdloop_ping(loop); + } + else + close(s->fd); +} + +void +sk_stop(sock *s) +{ + sockets_remove(birdloop_current, s); +} + +static inline uint sk_want_events(sock *s) +{ return (s->rx_hook ? POLLIN : 0) | ((s->ttx != s->tpos) ? POLLOUT : 0); } + +/* +FIXME: this should be called from sock code + +static void +sockets_update(struct birdloop *loop, sock *s) +{ + if (s->index >= 0) + loop->poll_fd.data[s->index].events = sk_want_events(s); +} +*/ + +static void +sockets_prepare(struct birdloop *loop) +{ + BUFFER_SET(loop->poll_sk, loop->sock_num + 1); + BUFFER_SET(loop->poll_fd, loop->sock_num + 1); + + struct pollfd *pfd = loop->poll_fd.data; + sock **psk = loop->poll_sk.data; + uint i = 0; + node *n; + + WALK_LIST(n, loop->sock_list) + { + sock *s = SKIP_BACK(sock, n, n); + + ASSERT(i < loop->sock_num); + + s->index = i; + *psk = s; + pfd->fd = s->fd; + pfd->events = sk_want_events(s); + pfd->revents = 0; + + pfd++; + psk++; + i++; + } + + ASSERT(i == loop->sock_num); + + /* Add internal wakeup fd */ + *psk = NULL; + pfd->fd = loop->wakeup_fds[0]; + pfd->events = POLLIN; + pfd->revents = 0; + + loop->poll_changed = 0; +} + +static void +sockets_close_fds(struct birdloop *loop) +{ + struct pollfd *pfd = loop->poll_fd.data; + sock **psk = loop->poll_sk.data; + int poll_num = loop->poll_fd.used - 1; + + int i; + for (i = 0; i < poll_num; i++) + if (psk[i] == NULL) + close(pfd[i].fd); + + loop->close_scheduled = 0; +} + +int sk_read(sock *s, int revents); +int sk_write(sock *s); + +static void +sockets_fire(struct birdloop *loop) +{ + struct pollfd *pfd = loop->poll_fd.data; + sock **psk = loop->poll_sk.data; + int poll_num = loop->poll_fd.used - 1; + + times_update(); + + /* Last fd is internal wakeup fd */ + if (pfd[poll_num].revents & POLLIN) + wakeup_drain(loop); + + int i; + for (i = 0; i < poll_num; pfd++, psk++, i++) + { + int e = 1; + + if (! pfd->revents) + continue; + + if (pfd->revents & POLLNVAL) + die("poll: invalid fd %d", pfd->fd); + + if (pfd->revents & POLLIN) + while (e && *psk && (*psk)->rx_hook) + e = sk_read(*psk, pfd->revents); + + e = 1; + if (pfd->revents & POLLOUT) + { + loop->poll_changed = 1; + while (e && *psk) + e = sk_write(*psk); + } + } +} + + +/* + * Birdloop + */ + +struct birdloop main_birdloop; + +static void birdloop_enter_locked(struct birdloop *loop); + +void +birdloop_init(void) +{ + wakeup_init(&main_birdloop); + + main_birdloop.time.domain = the_bird_domain.the_bird; + main_birdloop.time.loop = &main_birdloop; + + times_update(); + timers_init(&main_birdloop.time, &root_pool); + + birdloop_enter_locked(&main_birdloop); +} + +static void *birdloop_main(void *arg); + +struct birdloop * +birdloop_new(pool *pp, uint order, const char *name) +{ + struct domain_generic *dg = domain_new(name, order); + + pool *p = rp_new(pp, name); + struct birdloop *loop = mb_allocz(p, sizeof(struct birdloop)); + loop->pool = p; + + loop->time.domain = dg; + loop->time.loop = loop; + + birdloop_enter(loop); + + wakeup_init(loop); + ev_init_list(&loop->event_list, loop, name); + timers_init(&loop->time, p); + sockets_init(loop); + + int e = 0; + + if (e = pthread_attr_init(&loop->thread_attr)) + die("pthread_attr_init() failed: %M", e); + + if (e = pthread_attr_setstacksize(&loop->thread_attr, THREAD_STACK_SIZE)) + die("pthread_attr_setstacksize(%u) failed: %M", THREAD_STACK_SIZE, e); + + if (e = pthread_attr_setdetachstate(&loop->thread_attr, PTHREAD_CREATE_DETACHED)) + die("pthread_attr_setdetachstate(PTHREAD_CREATE_DETACHED) failed: %M", e); + + if (e = pthread_create(&loop->thread_id, &loop->thread_attr, birdloop_main, loop)) + die("pthread_create() failed: %M", e); + + birdloop_leave(loop); + + return loop; +} + +static void +birdloop_do_stop(struct birdloop *loop, void (*stopped)(void *data), void *data) +{ + loop->stopped = stopped; + loop->stop_data = data; + wakeup_do_kick(loop); +} + +void +birdloop_stop(struct birdloop *loop, void (*stopped)(void *data), void *data) +{ + DG_LOCK(loop->time.domain); + birdloop_do_stop(loop, stopped, data); + DG_UNLOCK(loop->time.domain); +} + +void +birdloop_stop_self(struct birdloop *loop, void (*stopped)(void *data), void *data) +{ + ASSERT_DIE(loop == birdloop_current); + ASSERT_DIE(DG_IS_LOCKED(loop->time.domain)); + + birdloop_do_stop(loop, stopped, data); +} + +void +birdloop_free(struct birdloop *loop) +{ + ASSERT_DIE(loop->links == 0); + ASSERT_DIE(pthread_equal(pthread_self(), loop->thread_id)); + + rcu_birdloop_stop(&loop->rcu); + pthread_attr_destroy(&loop->thread_attr); + + domain_free(loop->time.domain); + rfree(loop->pool); +} + +static void +birdloop_enter_locked(struct birdloop *loop) +{ + ASSERT_DIE(DG_IS_LOCKED(loop->time.domain)); + ASSERT_DIE(!birdloop_inside(loop)); + + /* Store the old context */ + loop->prev_loop = birdloop_current; + + /* Put the new context */ + birdloop_current = loop; +} + +void +birdloop_enter(struct birdloop *loop) +{ + DG_LOCK(loop->time.domain); + return birdloop_enter_locked(loop); +} + +static void +birdloop_leave_locked(struct birdloop *loop) +{ + /* Check the current context */ + ASSERT_DIE(birdloop_current == loop); + + /* Send pending pings */ + if (loop->ping_pending) + { + loop->ping_pending = 0; + birdloop_do_ping(loop); + } + + /* Restore the old context */ + birdloop_current = loop->prev_loop; +} + +void +birdloop_leave(struct birdloop *loop) +{ + birdloop_leave_locked(loop); + DG_UNLOCK(loop->time.domain); +} + +void +birdloop_mask_wakeups(struct birdloop *loop) +{ + ASSERT_DIE(birdloop_wakeup_masked == NULL); + birdloop_wakeup_masked = loop; +} + +void +birdloop_unmask_wakeups(struct birdloop *loop) +{ + ASSERT_DIE(birdloop_wakeup_masked == loop); + birdloop_wakeup_masked = NULL; + if (birdloop_wakeup_masked_count) + wakeup_do_kick(loop); + + birdloop_wakeup_masked_count = 0; +} + +void +birdloop_link(struct birdloop *loop) +{ + ASSERT_DIE(birdloop_inside(loop)); + loop->links++; +} + +void +birdloop_unlink(struct birdloop *loop) +{ + ASSERT_DIE(birdloop_inside(loop)); + loop->links--; +} + +static void * +birdloop_main(void *arg) +{ + struct birdloop *loop = arg; + timer *t; + int rv, timeout; + + rcu_birdloop_start(&loop->rcu); + + btime loop_begin = current_time(); + + tmp_init(loop->pool); + + birdloop_enter(loop); + while (1) + { + timers_fire(&loop->time, 0); + if (ev_run_list(&loop->event_list)) + timeout = 0; + else if (t = timers_first(&loop->time)) + timeout = (tm_remains(t) TO_MS) + 1; + else + timeout = -1; + + if (loop->poll_changed) + sockets_prepare(loop); + + btime duration = current_time() - loop_begin; + if (duration > config->watchdog_warning) + log(L_WARN "I/O loop cycle took %d ms", (int) (duration TO_MS)); + + birdloop_leave(loop); + + try: + rv = poll(loop->poll_fd.data, loop->poll_fd.used, timeout); + if (rv < 0) + { + if (errno == EINTR || errno == EAGAIN) + goto try; + die("poll: %m"); + } + + birdloop_enter(loop); + + if (loop->close_scheduled) + sockets_close_fds(loop); + + if (loop->stopped) + break; + + loop_begin = current_time(); + + if (rv) + sockets_fire(loop); + + atomic_exchange_explicit(&loop->ping_sent, 0, memory_order_acq_rel); + } + + /* Flush remaining events */ + ASSERT_DIE(!ev_run_list(&loop->event_list)); + + /* No timers allowed */ + ASSERT_DIE(timers_count(&loop->time) == 0); + ASSERT_DIE(EMPTY_LIST(loop->sock_list)); + ASSERT_DIE(loop->sock_num == 0); + + birdloop_leave(loop); + loop->stopped(loop->stop_data); + + return NULL; +} + +void +birdloop_yield(void) +{ + usleep(100); +} |