diff options
Diffstat (limited to 'events/events_standard.c')
| -rw-r--r-- | events/events_standard.c | 607 |
1 files changed, 0 insertions, 607 deletions
diff --git a/events/events_standard.c b/events/events_standard.c deleted file mode 100644 index 11128d76..00000000 --- a/events/events_standard.c +++ /dev/null @@ -1,607 +0,0 @@ -/* - Unix SMB/CIFS implementation. - main select loop and event handling - Copyright (C) Andrew Tridgell 2003-2005 - Copyright (C) Stefan Metzmacher 2005 - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 3 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program. If not, see <http://www.gnu.org/licenses/>. -*/ - -/* - This is SAMBA's default event loop code - - - we try to use epoll if configure detected support for it - otherwise we use select() - - if epoll is broken on the system or the kernel doesn't support it - at runtime we fallback to select() -*/ - -#include "replace.h" -#include "system/filesys.h" -#include "system/network.h" -#include "system/select.h" /* needed for HAVE_EVENTS_EPOLL */ -#include "events.h" -#include "events_util.h" -#include "events_internal.h" - -struct std_event_context { - /* a pointer back to the generic event_context */ - struct event_context *ev; - - /* list of filedescriptor events */ - struct fd_event *fd_events; - - /* the maximum file descriptor number in fd_events */ - int maxfd; - - /* information for exiting from the event loop */ - int exit_code; - - /* this is changed by the destructors for the fd event - type. It is used to detect event destruction by event - handlers, which means the code that is calling the event - handler needs to assume that the linked list is no longer - valid - */ - uint32_t destruction_count; - - /* when using epoll this is the handle from epoll_create */ - int epoll_fd; - - /* our pid at the time the epoll_fd was created */ - pid_t pid; -}; - -/* use epoll if it is available */ -#if HAVE_EVENTS_EPOLL -/* - called when a epoll call fails, and we should fallback - to using select -*/ -static void epoll_fallback_to_select(struct std_event_context *std_ev, const char *reason) -{ - ev_debug(std_ev->ev, EV_DEBUG_FATAL, - "%s (%s) - falling back to select()\n", - reason, strerror(errno)); - close(std_ev->epoll_fd); - std_ev->epoll_fd = -1; - talloc_set_destructor(std_ev, NULL); -} - -/* - map from EVENT_FD_* to EPOLLIN/EPOLLOUT -*/ -static uint32_t epoll_map_flags(uint16_t flags) -{ - uint32_t ret = 0; - if (flags & EVENT_FD_READ) ret |= (EPOLLIN | EPOLLERR | EPOLLHUP); - if (flags & EVENT_FD_WRITE) ret |= (EPOLLOUT | EPOLLERR | EPOLLHUP); - return ret; -} - -/* - free the epoll fd -*/ -static int epoll_ctx_destructor(struct std_event_context *std_ev) -{ - if (std_ev->epoll_fd != -1) { - close(std_ev->epoll_fd); - } - std_ev->epoll_fd = -1; - return 0; -} - -/* - init the epoll fd -*/ -static void epoll_init_ctx(struct std_event_context *std_ev) -{ - std_ev->epoll_fd = epoll_create(64); - std_ev->pid = getpid(); - talloc_set_destructor(std_ev, epoll_ctx_destructor); -} - -static void epoll_add_event(struct std_event_context *std_ev, struct fd_event *fde); - -/* - reopen the epoll handle when our pid changes - see http://junkcode.samba.org/ftp/unpacked/junkcode/epoll_fork.c for an - demonstration of why this is needed - */ -static void epoll_check_reopen(struct std_event_context *std_ev) -{ - struct fd_event *fde; - - if (std_ev->pid == getpid()) { - return; - } - - close(std_ev->epoll_fd); - std_ev->epoll_fd = epoll_create(64); - if (std_ev->epoll_fd == -1) { - ev_debug(std_ev->ev, EV_DEBUG_FATAL, - "Failed to recreate epoll handle after fork\n"); - return; - } - std_ev->pid = getpid(); - for (fde=std_ev->fd_events;fde;fde=fde->next) { - epoll_add_event(std_ev, fde); - } -} - -#define EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT (1<<0) -#define EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR (1<<1) -#define EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR (1<<2) - -/* - add the epoll event to the given fd_event -*/ -static void epoll_add_event(struct std_event_context *std_ev, struct fd_event *fde) -{ - struct epoll_event event; - if (std_ev->epoll_fd == -1) return; - - fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; - - /* if we don't want events yet, don't add an epoll_event */ - if (fde->flags == 0) return; - - ZERO_STRUCT(event); - event.events = epoll_map_flags(fde->flags); - event.data.ptr = fde; - if (epoll_ctl(std_ev->epoll_fd, EPOLL_CTL_ADD, fde->fd, &event) != 0) { - epoll_fallback_to_select(std_ev, "EPOLL_CTL_ADD failed"); - } - fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; - - /* only if we want to read we want to tell the event handler about errors */ - if (fde->flags & EVENT_FD_READ) { - fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; - } -} - -/* - delete the epoll event for given fd_event -*/ -static void epoll_del_event(struct std_event_context *std_ev, struct fd_event *fde) -{ - struct epoll_event event; - if (std_ev->epoll_fd == -1) return; - - fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; - - /* if there's no epoll_event, we don't need to delete it */ - if (!(fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT)) return; - - ZERO_STRUCT(event); - event.events = epoll_map_flags(fde->flags); - event.data.ptr = fde; - epoll_ctl(std_ev->epoll_fd, EPOLL_CTL_DEL, fde->fd, &event); - fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; -} - -/* - change the epoll event to the given fd_event -*/ -static void epoll_mod_event(struct std_event_context *std_ev, struct fd_event *fde) -{ - struct epoll_event event; - if (std_ev->epoll_fd == -1) return; - - fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; - - ZERO_STRUCT(event); - event.events = epoll_map_flags(fde->flags); - event.data.ptr = fde; - if (epoll_ctl(std_ev->epoll_fd, EPOLL_CTL_MOD, fde->fd, &event) != 0) { - epoll_fallback_to_select(std_ev, "EPOLL_CTL_MOD failed"); - } - - /* only if we want to read we want to tell the event handler about errors */ - if (fde->flags & EVENT_FD_READ) { - fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; - } -} - -static void epoll_change_event(struct std_event_context *std_ev, struct fd_event *fde) -{ - bool got_error = (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR); - bool want_read = (fde->flags & EVENT_FD_READ); - bool want_write= (fde->flags & EVENT_FD_WRITE); - - if (std_ev->epoll_fd == -1) return; - - fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; - - /* there's already an event */ - if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT) { - if (want_read || (want_write && !got_error)) { - epoll_mod_event(std_ev, fde); - return; - } - /* - * if we want to match the select behavior, we need to remove the epoll_event - * when the caller isn't interested in events. - * - * this is because epoll reports EPOLLERR and EPOLLHUP, even without asking for them - */ - epoll_del_event(std_ev, fde); - return; - } - - /* there's no epoll_event attached to the fde */ - if (want_read || (want_write && !got_error)) { - epoll_add_event(std_ev, fde); - return; - } -} - -/* - event loop handling using epoll -*/ -static int epoll_event_loop(struct std_event_context *std_ev, struct timeval *tvalp) -{ - int ret, i; -#define MAXEVENTS 8 - struct epoll_event events[MAXEVENTS]; - uint32_t destruction_count = ++std_ev->destruction_count; - int timeout = -1; - - if (std_ev->epoll_fd == -1) return -1; - - if (tvalp) { - /* it's better to trigger timed events a bit later than to early */ - timeout = ((tvalp->tv_usec+999) / 1000) + (tvalp->tv_sec*1000); - } - - if (std_ev->ev->num_signal_handlers && - common_event_check_signal(std_ev->ev)) { - return 0; - } - - ret = epoll_wait(std_ev->epoll_fd, events, MAXEVENTS, timeout); - - if (ret == -1 && errno == EINTR && std_ev->ev->num_signal_handlers) { - if (common_event_check_signal(std_ev->ev)) { - return 0; - } - } - - if (ret == -1 && errno != EINTR) { - epoll_fallback_to_select(std_ev, "epoll_wait() failed"); - return -1; - } - - if (ret == 0 && tvalp) { - /* we don't care about a possible delay here */ - common_event_loop_timer_delay(std_ev->ev); - return 0; - } - - for (i=0;i<ret;i++) { - struct fd_event *fde = talloc_get_type(events[i].data.ptr, - struct fd_event); - uint16_t flags = 0; - - if (fde == NULL) { - epoll_fallback_to_select(std_ev, "epoll_wait() gave bad data"); - return -1; - } - if (events[i].events & (EPOLLHUP|EPOLLERR)) { - fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR; - /* - * if we only wait for EVENT_FD_WRITE, we should not tell the - * event handler about it, and remove the epoll_event, - * as we only report errors when waiting for read events, - * to match the select() behavior - */ - if (!(fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR)) { - epoll_del_event(std_ev, fde); - continue; - } - flags |= EVENT_FD_READ; - } - if (events[i].events & EPOLLIN) flags |= EVENT_FD_READ; - if (events[i].events & EPOLLOUT) flags |= EVENT_FD_WRITE; - if (flags) { - fde->handler(std_ev->ev, fde, flags, fde->private_data); - if (destruction_count != std_ev->destruction_count) { - break; - } - } - } - - return 0; -} -#else -#define epoll_init_ctx(std_ev) -#define epoll_add_event(std_ev,fde) -#define epoll_del_event(std_ev,fde) -#define epoll_change_event(std_ev,fde) -#define epoll_event_loop(std_ev,tvalp) (-1) -#define epoll_check_reopen(std_ev) -#endif - -/* - create a std_event_context structure. -*/ -static int std_event_context_init(struct event_context *ev) -{ - struct std_event_context *std_ev; - - std_ev = talloc_zero(ev, struct std_event_context); - if (!std_ev) return -1; - std_ev->ev = ev; - std_ev->epoll_fd = -1; - - epoll_init_ctx(std_ev); - - ev->additional_data = std_ev; - return 0; -} - -/* - recalculate the maxfd -*/ -static void calc_maxfd(struct std_event_context *std_ev) -{ - struct fd_event *fde; - - std_ev->maxfd = 0; - for (fde = std_ev->fd_events; fde; fde = fde->next) { - if (fde->fd > std_ev->maxfd) { - std_ev->maxfd = fde->fd; - } - } -} - - -/* to mark the ev->maxfd invalid - * this means we need to recalculate it - */ -#define EVENT_INVALID_MAXFD (-1) - -/* - destroy an fd_event -*/ -static int std_event_fd_destructor(struct fd_event *fde) -{ - struct event_context *ev = fde->event_ctx; - struct std_event_context *std_ev = talloc_get_type(ev->additional_data, - struct std_event_context); - - epoll_check_reopen(std_ev); - - if (std_ev->maxfd == fde->fd) { - std_ev->maxfd = EVENT_INVALID_MAXFD; - } - - DLIST_REMOVE(std_ev->fd_events, fde); - std_ev->destruction_count++; - - epoll_del_event(std_ev, fde); - - if (fde->flags & EVENT_FD_AUTOCLOSE) { - close(fde->fd); - fde->fd = -1; - } - - return 0; -} - -/* - add a fd based event - return NULL on failure (memory allocation error) -*/ -static struct fd_event *std_event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx, - int fd, uint16_t flags, - event_fd_handler_t handler, - void *private_data) -{ - struct std_event_context *std_ev = talloc_get_type(ev->additional_data, - struct std_event_context); - struct fd_event *fde; - - epoll_check_reopen(std_ev); - - fde = talloc(mem_ctx?mem_ctx:ev, struct fd_event); - if (!fde) return NULL; - - fde->event_ctx = ev; - fde->fd = fd; - fde->flags = flags; - fde->handler = handler; - fde->private_data = private_data; - fde->additional_flags = 0; - fde->additional_data = NULL; - - DLIST_ADD(std_ev->fd_events, fde); - if ((std_ev->maxfd != EVENT_INVALID_MAXFD) - && (fde->fd > std_ev->maxfd)) { - std_ev->maxfd = fde->fd; - } - talloc_set_destructor(fde, std_event_fd_destructor); - - epoll_add_event(std_ev, fde); - - return fde; -} - - -/* - return the fd event flags -*/ -static uint16_t std_event_get_fd_flags(struct fd_event *fde) -{ - return fde->flags; -} - -/* - set the fd event flags -*/ -static void std_event_set_fd_flags(struct fd_event *fde, uint16_t flags) -{ - struct event_context *ev; - struct std_event_context *std_ev; - - if (fde->flags == flags) return; - - ev = fde->event_ctx; - std_ev = talloc_get_type(ev->additional_data, struct std_event_context); - - fde->flags = flags; - - epoll_check_reopen(std_ev); - - epoll_change_event(std_ev, fde); -} - -/* - event loop handling using select() -*/ -static int std_event_loop_select(struct std_event_context *std_ev, struct timeval *tvalp) -{ - fd_set r_fds, w_fds; - struct fd_event *fde; - int selrtn; - uint32_t destruction_count = ++std_ev->destruction_count; - - /* we maybe need to recalculate the maxfd */ - if (std_ev->maxfd == EVENT_INVALID_MAXFD) { - calc_maxfd(std_ev); - } - - FD_ZERO(&r_fds); - FD_ZERO(&w_fds); - - /* setup any fd events */ - for (fde = std_ev->fd_events; fde; fde = fde->next) { - if (fde->flags & EVENT_FD_READ) { - FD_SET(fde->fd, &r_fds); - } - if (fde->flags & EVENT_FD_WRITE) { - FD_SET(fde->fd, &w_fds); - } - } - - if (std_ev->ev->num_signal_handlers && - common_event_check_signal(std_ev->ev)) { - return 0; - } - - selrtn = select(std_ev->maxfd+1, &r_fds, &w_fds, NULL, tvalp); - - if (selrtn == -1 && errno == EINTR && - std_ev->ev->num_signal_handlers) { - common_event_check_signal(std_ev->ev); - return 0; - } - - if (selrtn == -1 && errno == EBADF) { - /* the socket is dead! this should never - happen as the socket should have first been - made readable and that should have removed - the event, so this must be a bug. This is a - fatal error. */ - ev_debug(std_ev->ev, EV_DEBUG_FATAL, - "ERROR: EBADF on std_event_loop_once\n"); - std_ev->exit_code = EBADF; - return -1; - } - - if (selrtn == 0 && tvalp) { - /* we don't care about a possible delay here */ - common_event_loop_timer_delay(std_ev->ev); - return 0; - } - - if (selrtn > 0) { - /* at least one file descriptor is ready - check - which ones and call the handler, being careful to allow - the handler to remove itself when called */ - for (fde = std_ev->fd_events; fde; fde = fde->next) { - uint16_t flags = 0; - - if (FD_ISSET(fde->fd, &r_fds)) flags |= EVENT_FD_READ; - if (FD_ISSET(fde->fd, &w_fds)) flags |= EVENT_FD_WRITE; - if (flags) { - fde->handler(std_ev->ev, fde, flags, fde->private_data); - if (destruction_count != std_ev->destruction_count) { - break; - } - } - } - } - - return 0; -} - -/* - do a single event loop using the events defined in ev -*/ -static int std_event_loop_once(struct event_context *ev) -{ - struct std_event_context *std_ev = talloc_get_type(ev->additional_data, - struct std_event_context); - struct timeval tval; - - tval = common_event_loop_timer_delay(ev); - if (ev_timeval_is_zero(&tval)) { - return 0; - } - - epoll_check_reopen(std_ev); - - if (epoll_event_loop(std_ev, &tval) == 0) { - return 0; - } - - return std_event_loop_select(std_ev, &tval); -} - -/* - return on failure or (with 0) if all fd events are removed -*/ -static int std_event_loop_wait(struct event_context *ev) -{ - struct std_event_context *std_ev = talloc_get_type(ev->additional_data, - struct std_event_context); - std_ev->exit_code = 0; - - while (std_ev->fd_events && std_ev->exit_code == 0) { - if (std_event_loop_once(ev) != 0) { - break; - } - } - - return std_ev->exit_code; -} - -static const struct event_ops std_event_ops = { - .context_init = std_event_context_init, - .add_fd = std_event_add_fd, - .get_fd_flags = std_event_get_fd_flags, - .set_fd_flags = std_event_set_fd_flags, - .add_timed = common_event_add_timed, - .add_signal = common_event_add_signal, - .loop_once = std_event_loop_once, - .loop_wait = std_event_loop_wait, -}; - - -bool events_standard_init(void) -{ - return event_register_backend("standard", &std_event_ops); -} - |