X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fio%2Fpoll.c;h=17f9384587d92e39b37e199b0f05159bb899d112;hp=36af33ef0854de3323c8f29c4dc522c976091764;hb=HEAD;hpb=61f58ff94e35c9b8ac5488554e2554bc5c9888b3 diff --git a/ccan/io/poll.c b/ccan/io/poll.c index 36af33ef..634f83d2 100644 --- a/ccan/io/poll.c +++ b/ccan/io/poll.c @@ -11,12 +11,12 @@ #include #include -static size_t num_fds = 0, max_fds = 0, num_waiting = 0; +static size_t num_fds = 0, max_fds = 0, num_waiting = 0, num_always = 0, max_always = 0, num_exclusive = 0; static struct pollfd *pollfds = NULL; static struct fd **fds = NULL; -static LIST_HEAD(closing); -static LIST_HEAD(always); +static struct io_plan **always = NULL; static struct timemono (*nowfn)(void) = time_mono; +static int (*pollfn)(struct pollfd *fds, nfds_t nfds, int timeout) = poll; struct timemono (*io_time_override(struct timemono (*now)(void)))(void) { @@ -25,6 +25,13 @@ struct timemono (*io_time_override(struct timemono (*now)(void)))(void) return old; } +int (*io_poll_override(int (*poll)(struct pollfd *fds, nfds_t nfds, int timeout)))(struct pollfd *, nfds_t, int) +{ + int (*old)(struct pollfd *fds, nfds_t nfds, int timeout) = pollfn; + pollfn = poll; + return old; +} + static bool add_fd(struct fd *fd, short events) { if (!max_fds) { @@ -51,12 +58,13 @@ static bool add_fd(struct fd *fd, short events) pollfds[num_fds].events = events; /* In case it's idle. */ if (!events) - pollfds[num_fds].fd = -fd->fd; + pollfds[num_fds].fd = -fd->fd - 1; else pollfds[num_fds].fd = fd->fd; pollfds[num_fds].revents = 0; /* In case we're iterating now */ fds[num_fds] = fd; fd->backend_info = num_fds; + fd->exclusive[0] = fd->exclusive[1] = false; num_fds++; if (events) num_waiting++; @@ -83,65 +91,122 @@ static void del_fd(struct fd *fd) pollfds = tal_free(pollfds); fds = NULL; max_fds = 0; + if (num_always == 0) { + always = tal_free(always); + max_always = 0; + } } num_fds--; fd->backend_info = -1; - /* Closing a local socket doesn't wake poll() because other end - * has them open. See 2.6. When should I use shutdown()? - * in http://www.faqs.org/faqs/unix-faq/socket/ */ - shutdown(fd->fd, SHUT_RDWR); + if (fd->exclusive[IO_IN]) + num_exclusive--; + if (fd->exclusive[IO_OUT]) + num_exclusive--; +} - close(fd->fd); +static void destroy_listener(struct io_listener *l) +{ + close(l->fd.fd); + del_fd(&l->fd); } bool add_listener(struct io_listener *l) { if (!add_fd(&l->fd, POLLIN)) return false; + tal_add_destructor(l, destroy_listener); return true; } -void remove_from_always(struct io_conn *conn) +static int find_always(const struct io_plan *plan) { - list_del_init(&conn->always); + size_t i = 0; + + for (i = 0; i < num_always; i++) + if (always[i] == plan) + return i; + return -1; } -void backend_new_closing(struct io_conn *conn) +static void remove_from_always(const struct io_plan *plan) { - /* In case it's on always list, remove it. */ - list_del_init(&conn->always); - list_add_tail(&closing, &conn->closing); + int pos; + + if (plan->status != IO_ALWAYS) + return; + + pos = find_always(plan); + assert(pos >= 0); + + /* Move last one down if we made a hole */ + if (pos != num_always-1) + always[pos] = always[num_always-1]; + num_always--; + + /* Only free if no fds left either. */ + if (num_always == 0 && max_fds == 0) { + always = tal_free(always); + max_always = 0; + } } -void backend_new_always(struct io_conn *conn) +bool backend_new_always(struct io_plan *plan) { - /* In case it's already in always list. */ - list_del(&conn->always); - list_add_tail(&always, &conn->always); + assert(find_always(plan) == -1); + + if (!max_always) { + assert(num_always == 0); + always = tal_arr(NULL, struct io_plan *, 8); + if (!always) + return false; + max_always = 8; + } + + if (num_always + 1 > max_always) { + size_t num = max_always * 2; + + if (!tal_resize(&always, num)) + return false; + max_always = num; + } + + always[num_always++] = plan; + return true; } -void backend_new_plan(struct io_conn *conn) +static void setup_pfd(struct io_conn *conn, struct pollfd *pfd) { - struct pollfd *pfd = &pollfds[conn->fd.backend_info]; - - if (pfd->events) - num_waiting--; + assert(pfd == &pollfds[conn->fd.backend_info]); pfd->events = 0; - if (conn->plan[IO_IN].status == IO_POLLING) + if (conn->plan[IO_IN].status == IO_POLLING_NOTSTARTED + || conn->plan[IO_IN].status == IO_POLLING_STARTED) pfd->events |= POLLIN; - if (conn->plan[IO_OUT].status == IO_POLLING) + if (conn->plan[IO_OUT].status == IO_POLLING_NOTSTARTED + || conn->plan[IO_OUT].status == IO_POLLING_STARTED) pfd->events |= POLLOUT; if (pfd->events) { - num_waiting++; pfd->fd = conn->fd.fd; } else { - pfd->fd = -conn->fd.fd; + pfd->fd = -conn->fd.fd - 1; } } +void backend_new_plan(struct io_conn *conn) +{ + struct pollfd *pfd = &pollfds[conn->fd.backend_info]; + + if (pfd->events) + num_waiting--; + + setup_pfd(conn, pfd); + + if (pfd->events) + num_waiting++; +} + void backend_wake(const void *wait) { unsigned int i; @@ -164,25 +229,41 @@ void backend_wake(const void *wait) } } -bool add_conn(struct io_conn *c) +static void destroy_conn(struct io_conn *conn, bool close_fd) { - return add_fd(&c->fd, 0); -} + int saved_errno = errno; -static void del_conn(struct io_conn *conn) -{ + if (close_fd) + close(conn->fd.fd); del_fd(&conn->fd); + + remove_from_always(&conn->plan[IO_IN]); + remove_from_always(&conn->plan[IO_OUT]); + + /* errno saved/restored by tal_free itself. */ if (conn->finish) { - /* Saved by io_close */ - errno = conn->plan[IO_IN].arg.u1.s; + errno = saved_errno; conn->finish(conn, conn->finish_arg); } - tal_free(conn); } -void del_listener(struct io_listener *l) +static void destroy_conn_close_fd(struct io_conn *conn) { - del_fd(&l->fd); + destroy_conn(conn, true); +} + +bool add_conn(struct io_conn *c) +{ + if (!add_fd(&c->fd, 0)) + return false; + tal_add_destructor(c, destroy_conn_close_fd); + return true; +} + +void cleanup_conn_without_close(struct io_conn *conn) +{ + tal_del_destructor(conn, destroy_conn_close_fd); + destroy_conn(conn, false); } static void accept_conn(struct io_listener *l) @@ -196,37 +277,94 @@ static void accept_conn(struct io_listener *l) io_new_conn(l->ctx, fd, l->init, l->arg); } -/* It's OK to miss some, as long as we make progress. */ -static bool close_conns(void) +/* Return pointer to exclusive flag for this plan. */ +static bool *exclusive(struct io_plan *plan) { - bool ret = false; struct io_conn *conn; - while ((conn = list_pop(&closing, struct io_conn, closing)) != NULL) { - assert(conn->plan[IO_IN].status == IO_CLOSING); - assert(conn->plan[IO_OUT].status == IO_CLOSING); + conn = container_of(plan, struct io_conn, plan[plan->dir]); + return &conn->fd.exclusive[plan->dir]; +} + +/* For simplicity, we do one always at a time */ +static bool handle_always(void) +{ + int i; + + /* Backwards is simple easier to remove entries */ + for (i = num_always - 1; i >= 0; i--) { + struct io_plan *plan = always[i]; - del_conn(conn); - ret = true; + if (num_exclusive && !*exclusive(plan)) + continue; + /* Remove first: it might re-add */ + if (i != num_always-1) + always[i] = always[num_always-1]; + num_always--; + io_do_always(plan); + return true; } - return ret; + + return false; } -static bool handle_always(void) +bool backend_set_exclusive(struct io_plan *plan, bool excl) { - bool ret = false; - struct io_conn *conn; + bool *excl_ptr = exclusive(plan); + + if (excl != *excl_ptr) { + *excl_ptr = excl; + if (!excl) + num_exclusive--; + else + num_exclusive++; + } + + return num_exclusive != 0; +} + +/* FIXME: We could do this once at set_exclusive time, and catch everywhere + * else that we manipulate events. */ +static void exclude_pollfds(void) +{ + size_t i; + + if (num_exclusive == 0) + return; + + for (i = 0; i < num_fds; i++) { + struct pollfd *pfd = &pollfds[fds[i]->backend_info]; - while ((conn = list_pop(&always, struct io_conn, always)) != NULL) { - assert(conn->plan[IO_IN].status == IO_ALWAYS - || conn->plan[IO_OUT].status == IO_ALWAYS); + if (!fds[i]->exclusive[IO_IN]) + pfd->events &= ~POLLIN; + if (!fds[i]->exclusive[IO_OUT]) + pfd->events &= ~POLLOUT; - /* Re-initialize, for next time. */ - list_node_init(&conn->always); - io_do_always(conn); - ret = true; + /* If we're not listening, we don't want error events + * either. */ + if (!pfd->events) + pfd->fd = -fds[i]->fd - 1; + } +} + +static void restore_pollfds(void) +{ + size_t i; + + if (num_exclusive == 0) + return; + + for (i = 0; i < num_fds; i++) { + struct pollfd *pfd = &pollfds[fds[i]->backend_info]; + + if (fds[i]->listener) { + pfd->events = POLLIN; + pfd->fd = fds[i]->fd; + } else { + struct io_conn *conn = (void *)fds[i]; + setup_pfd(conn, pfd); + } } - return ret; } /* This is the main loop. */ @@ -244,11 +382,6 @@ void *io_loop(struct timers *timers, struct timer **expired) while (!io_loop_return) { int i, r, ms_timeout = -1; - if (close_conns()) { - /* Could have started/finished more. */ - continue; - } - if (handle_always()) { /* Could have started/finished more. */ continue; @@ -282,21 +415,38 @@ void *io_loop(struct timers *timers, struct timer **expired) } } - r = poll(pollfds, num_fds, ms_timeout); - if (r < 0) + /* We do this temporarily, assuming exclusive is unusual */ + exclude_pollfds(); + r = pollfn(pollfds, num_fds, ms_timeout); + restore_pollfds(); + + if (r < 0) { + /* Signals shouldn't break us, unless they set + * io_loop_return. */ + if (errno == EINTR) + continue; break; + } for (i = 0; i < num_fds && !io_loop_return; i++) { struct io_conn *c = (void *)fds[i]; int events = pollfds[i].revents; + /* Clear so we don't get confused if exclusive next time */ + pollfds[i].revents = 0; + if (r == 0) break; if (fds[i]->listener) { + struct io_listener *l = (void *)fds[i]; if (events & POLLIN) { - accept_conn((void *)c); + accept_conn(l); + r--; + } else if (events & (POLLHUP|POLLNVAL|POLLERR)) { r--; + errno = EBADF; + io_close_listener(l); } } else if (events & (POLLIN|POLLOUT)) { r--; @@ -309,10 +459,20 @@ void *io_loop(struct timers *timers, struct timer **expired) } } - close_conns(); - ret = io_loop_return; io_loop_return = NULL; return ret; } + +const void *io_have_fd(int fd, bool *listener) +{ + for (size_t i = 0; i < num_fds; i++) { + if (fds[i]->fd != fd) + continue; + if (listener) + *listener = fds[i]->listener; + return fds[i]; + } + return NULL; +}