diff options
Diffstat (limited to 'tevent_epoll.c')
| -rw-r--r-- | tevent_epoll.c | 957 |
1 files changed, 957 insertions, 0 deletions
diff --git a/tevent_epoll.c b/tevent_epoll.c new file mode 100644 index 0000000..1f1f47b --- /dev/null +++ b/tevent_epoll.c @@ -0,0 +1,957 @@ +/* + Unix SMB/CIFS implementation. + + main select loop and event handling - epoll implementation + + Copyright (C) Andrew Tridgell 2003-2005 + Copyright (C) Stefan Metzmacher 2005-2013 + Copyright (C) Jeremy Allison 2013 + + ** NOTE! The following LGPL license applies to the tevent + ** library. This does NOT imply that all of Samba is released + ** under the LGPL + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see <http://www.gnu.org/licenses/>. +*/ + +#include "replace.h" +#include "system/filesys.h" +#include "system/select.h" +#include "tevent.h" +#include "tevent_internal.h" +#include "tevent_util.h" + +struct epoll_event_context { + /* a pointer back to the generic event_context */ + struct tevent_context *ev; + + /* when using epoll this is the handle from epoll_create */ + int epoll_fd; + + pid_t pid; + + bool panic_force_replay; + bool *panic_state; + bool (*panic_fallback)(struct tevent_context *ev, bool replay); +}; + +#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) +#define EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX (1<<3) + +#ifdef TEST_PANIC_FALLBACK + +static int epoll_create_panic_fallback(struct epoll_event_context *epoll_ev, + int size) +{ + if (epoll_ev->panic_fallback == NULL) { + return epoll_create(size); + } + + /* 50% of the time, fail... */ + if ((random() % 2) == 0) { + errno = EINVAL; + return -1; + } + + return epoll_create(size); +} + +static int epoll_ctl_panic_fallback(struct epoll_event_context *epoll_ev, + int epfd, int op, int fd, + struct epoll_event *event) +{ + if (epoll_ev->panic_fallback == NULL) { + return epoll_ctl(epfd, op, fd, event); + } + + /* 50% of the time, fail... */ + if ((random() % 2) == 0) { + errno = EINVAL; + return -1; + } + + return epoll_ctl(epfd, op, fd, event); +} + +static int epoll_wait_panic_fallback(struct epoll_event_context *epoll_ev, + int epfd, + struct epoll_event *events, + int maxevents, + int timeout) +{ + if (epoll_ev->panic_fallback == NULL) { + return epoll_wait(epfd, events, maxevents, timeout); + } + + /* 50% of the time, fail... */ + if ((random() % 2) == 0) { + errno = EINVAL; + return -1; + } + + return epoll_wait(epfd, events, maxevents, timeout); +} + +#define epoll_create(_size) \ + epoll_create_panic_fallback(epoll_ev, _size) +#define epoll_ctl(_epfd, _op, _fd, _event) \ + epoll_ctl_panic_fallback(epoll_ev,_epfd, _op, _fd, _event) +#define epoll_wait(_epfd, _events, _maxevents, _timeout) \ + epoll_wait_panic_fallback(epoll_ev, _epfd, _events, _maxevents, _timeout) +#endif + +/* + called to set the panic fallback function. +*/ +_PRIVATE_ void tevent_epoll_set_panic_fallback(struct tevent_context *ev, + bool (*panic_fallback)(struct tevent_context *ev, + bool replay)) +{ + struct epoll_event_context *epoll_ev = + talloc_get_type_abort(ev->additional_data, + struct epoll_event_context); + + epoll_ev->panic_fallback = panic_fallback; +} + +/* + called when a epoll call fails +*/ +static void epoll_panic(struct epoll_event_context *epoll_ev, + const char *reason, bool replay) +{ + struct tevent_context *ev = epoll_ev->ev; + bool (*panic_fallback)(struct tevent_context *ev, bool replay); + + panic_fallback = epoll_ev->panic_fallback; + + if (epoll_ev->panic_state != NULL) { + *epoll_ev->panic_state = true; + } + + if (epoll_ev->panic_force_replay) { + replay = true; + } + + TALLOC_FREE(ev->additional_data); + + if (panic_fallback == NULL) { + tevent_debug(ev, TEVENT_DEBUG_FATAL, + "%s (%s) replay[%u] - calling abort()\n", + reason, strerror(errno), (unsigned)replay); + abort(); + } + + tevent_debug(ev, TEVENT_DEBUG_ERROR, + "%s (%s) replay[%u] - calling panic_fallback\n", + reason, strerror(errno), (unsigned)replay); + + if (!panic_fallback(ev, replay)) { + /* Fallback failed. */ + tevent_debug(ev, TEVENT_DEBUG_FATAL, + "%s (%s) replay[%u] - calling abort()\n", + reason, strerror(errno), (unsigned)replay); + abort(); + } +} + +/* + map from TEVENT_FD_* to EPOLLIN/EPOLLOUT +*/ +static uint32_t epoll_map_flags(uint16_t flags) +{ + uint32_t ret = 0; + if (flags & TEVENT_FD_READ) ret |= (EPOLLIN | EPOLLERR | EPOLLHUP); + if (flags & TEVENT_FD_WRITE) ret |= (EPOLLOUT | EPOLLERR | EPOLLHUP); + return ret; +} + +/* + free the epoll fd +*/ +static int epoll_ctx_destructor(struct epoll_event_context *epoll_ev) +{ + close(epoll_ev->epoll_fd); + epoll_ev->epoll_fd = -1; + return 0; +} + +/* + init the epoll fd +*/ +static int epoll_init_ctx(struct epoll_event_context *epoll_ev) +{ + epoll_ev->epoll_fd = epoll_create(64); + if (epoll_ev->epoll_fd == -1) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL, + "Failed to create epoll handle.\n"); + return -1; + } + + if (!ev_set_close_on_exec(epoll_ev->epoll_fd)) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_WARNING, + "Failed to set close-on-exec, file descriptor may be leaked to children.\n"); + } + + epoll_ev->pid = tevent_cached_getpid(); + talloc_set_destructor(epoll_ev, epoll_ctx_destructor); + + return 0; +} + +static void epoll_update_event(struct epoll_event_context *epoll_ev, struct tevent_fd *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 epoll_event_context *epoll_ev) +{ + struct tevent_fd *fde; + bool *caller_panic_state = epoll_ev->panic_state; + bool panic_triggered = false; + pid_t pid = tevent_cached_getpid(); + + if (epoll_ev->pid == pid) { + return; + } + + close(epoll_ev->epoll_fd); + epoll_ev->epoll_fd = epoll_create(64); + if (epoll_ev->epoll_fd == -1) { + epoll_panic(epoll_ev, "epoll_create() failed", false); + return; + } + + if (!ev_set_close_on_exec(epoll_ev->epoll_fd)) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_WARNING, + "Failed to set close-on-exec, file descriptor may be leaked to children.\n"); + } + + epoll_ev->pid = pid; + epoll_ev->panic_state = &panic_triggered; + for (fde=epoll_ev->ev->fd_events;fde;fde=fde->next) { + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + epoll_update_event(epoll_ev, fde); + + if (panic_triggered) { + if (caller_panic_state != NULL) { + *caller_panic_state = true; + } + return; + } + } + epoll_ev->panic_state = NULL; +} + +/* + epoll cannot add the same file descriptor twice, once + with read, once with write which is allowed by the + tevent backend. Multiplex the existing fde, flag it + as such so we can search for the correct fde on + event triggering. +*/ + +static int epoll_add_multiplex_fd(struct epoll_event_context *epoll_ev, + struct tevent_fd *add_fde) +{ + struct epoll_event event; + struct tevent_fd *mpx_fde; + int ret; + + /* Find the existing fde that caused the EEXIST error. */ + for (mpx_fde = epoll_ev->ev->fd_events; mpx_fde; mpx_fde = mpx_fde->next) { + if (mpx_fde->fd != add_fde->fd) { + continue; + } + + if (mpx_fde == add_fde) { + continue; + } + + break; + } + if (mpx_fde == NULL) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL, + "can't find multiplex fde for fd[%d]", + add_fde->fd); + return -1; + } + + if (mpx_fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX) { + /* Logic error. Can't have more than 2 multiplexed fde's. */ + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL, + "multiplex fde for fd[%d] is already multiplexed\n", + mpx_fde->fd); + return -1; + } + + /* + * The multiplex fde must have the same fd, and also + * already have an epoll event attached. + */ + if (!(mpx_fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT)) { + /* Logic error. Can't have more than 2 multiplexed fde's. */ + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL, + "multiplex fde for fd[%d] has no event\n", + mpx_fde->fd); + return -1; + } + + /* Modify the mpx_fde to add in the new flags. */ + ZERO_STRUCT(event); + event.events = epoll_map_flags(mpx_fde->flags); + event.events |= epoll_map_flags(add_fde->flags); + event.data.ptr = mpx_fde; + ret = epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_MOD, mpx_fde->fd, &event); + if (ret != 0 && errno == EBADF) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_ERROR, + "EPOLL_CTL_MOD EBADF for " + "add_fde[%p] mpx_fde[%p] fd[%d] - disabling\n", + add_fde, mpx_fde, add_fde->fd); + DLIST_REMOVE(epoll_ev->ev->fd_events, mpx_fde); + mpx_fde->wrapper = NULL; + mpx_fde->event_ctx = NULL; + DLIST_REMOVE(epoll_ev->ev->fd_events, add_fde); + add_fde->wrapper = NULL; + add_fde->event_ctx = NULL; + return 0; + } else if (ret != 0) { + return ret; + } + + /* + * Make each fde->additional_data pointers point at each other + * so we can look them up from each other. They are now paired. + */ + mpx_fde->additional_data = (struct tevent_fd *)add_fde; + add_fde->additional_data = (struct tevent_fd *)mpx_fde; + + /* Now flag both fde's as being multiplexed. */ + mpx_fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX; + add_fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX; + + /* we need to keep the GOT_ERROR flag */ + if (mpx_fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR) { + add_fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR; + } + + return 0; +} + +/* + add the epoll event to the given fd_event +*/ +static void epoll_add_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde) +{ + struct epoll_event event; + int ret; + struct tevent_fd *mpx_fde = NULL; + + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + + if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX) { + /* + * This is a multiplexed fde, we need to include both + * flags in the modified event. + */ + mpx_fde = talloc_get_type_abort(fde->additional_data, + struct tevent_fd); + + mpx_fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + mpx_fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + } + + ZERO_STRUCT(event); + event.events = epoll_map_flags(fde->flags); + if (mpx_fde != NULL) { + event.events |= epoll_map_flags(mpx_fde->flags); + } + event.data.ptr = fde; + ret = epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_ADD, fde->fd, &event); + if (ret != 0 && errno == EBADF) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_ERROR, + "EPOLL_CTL_ADD EBADF for " + "fde[%p] mpx_fde[%p] fd[%d] - disabling\n", + fde, mpx_fde, fde->fd); + DLIST_REMOVE(epoll_ev->ev->fd_events, fde); + fde->wrapper = NULL; + fde->event_ctx = NULL; + if (mpx_fde != NULL) { + DLIST_REMOVE(epoll_ev->ev->fd_events, mpx_fde); + mpx_fde->wrapper = NULL; + mpx_fde->event_ctx = NULL; + } + return; + } else if (ret != 0 && errno == EEXIST && mpx_fde == NULL) { + ret = epoll_add_multiplex_fd(epoll_ev, fde); + if (ret != 0) { + epoll_panic(epoll_ev, "epoll_add_multiplex_fd failed", + false); + return; + } + } else if (ret != 0) { + epoll_panic(epoll_ev, "EPOLL_CTL_ADD failed", false); + return; + } + + 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 & TEVENT_FD_READ) { + fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + } + + if (mpx_fde == NULL) { + return; + } + + mpx_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 (mpx_fde->flags & TEVENT_FD_READ) { + mpx_fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + } +} + +/* + delete the epoll event for given fd_event +*/ +static void epoll_del_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde) +{ + struct epoll_event event; + int ret; + struct tevent_fd *mpx_fde = NULL; + + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + + if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX) { + /* + * This is a multiplexed fde, we need to modify both events. + */ + mpx_fde = talloc_get_type_abort(fde->additional_data, + struct tevent_fd); + + mpx_fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + mpx_fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + } + + ZERO_STRUCT(event); + ret = epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_DEL, fde->fd, &event); + if (ret != 0 && errno == ENOENT) { + /* + * This can happen after a epoll_check_reopen + * within epoll_event_fd_destructor. + */ + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_TRACE, + "EPOLL_CTL_DEL ignoring ENOENT for fd[%d]\n", + fde->fd); + return; + } else if (ret != 0 && errno == EBADF) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_WARNING, + "EPOLL_CTL_DEL EBADF for " + "fde[%p] mpx_fde[%p] fd[%d] - disabling\n", + fde, mpx_fde, fde->fd); + DLIST_REMOVE(epoll_ev->ev->fd_events, fde); + fde->wrapper = NULL; + fde->event_ctx = NULL; + if (mpx_fde != NULL) { + DLIST_REMOVE(epoll_ev->ev->fd_events, mpx_fde); + mpx_fde->wrapper = NULL; + mpx_fde->event_ctx = NULL; + } + return; + } else if (ret != 0) { + epoll_panic(epoll_ev, "EPOLL_CTL_DEL failed", false); + return; + } +} + +/* + change the epoll event to the given fd_event +*/ +static void epoll_mod_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde) +{ + struct tevent_fd *mpx_fde = NULL; + struct epoll_event event; + int ret; + + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + + if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX) { + /* + * This is a multiplexed fde, we need to include both + * flags in the modified event. + */ + mpx_fde = talloc_get_type_abort(fde->additional_data, + struct tevent_fd); + + mpx_fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + mpx_fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + } + + ZERO_STRUCT(event); + event.events = epoll_map_flags(fde->flags); + if (mpx_fde != NULL) { + event.events |= epoll_map_flags(mpx_fde->flags); + } + event.data.ptr = fde; + ret = epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_MOD, fde->fd, &event); + if (ret != 0 && errno == EBADF) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_ERROR, + "EPOLL_CTL_MOD EBADF for " + "fde[%p] mpx_fde[%p] fd[%d] - disabling\n", + fde, mpx_fde, fde->fd); + DLIST_REMOVE(epoll_ev->ev->fd_events, fde); + fde->wrapper = NULL; + fde->event_ctx = NULL; + if (mpx_fde != NULL) { + DLIST_REMOVE(epoll_ev->ev->fd_events, mpx_fde); + mpx_fde->wrapper = NULL; + mpx_fde->event_ctx = NULL; + } + return; + } else if (ret != 0) { + epoll_panic(epoll_ev, "EPOLL_CTL_MOD failed", false); + return; + } + + 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 & TEVENT_FD_READ) { + fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + } + + if (mpx_fde == NULL) { + return; + } + + mpx_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 (mpx_fde->flags & TEVENT_FD_READ) { + mpx_fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR; + } +} + +static void epoll_update_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde) +{ + bool got_error = (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR); + bool want_read = (fde->flags & TEVENT_FD_READ); + bool want_write= (fde->flags & TEVENT_FD_WRITE); + struct tevent_fd *mpx_fde = NULL; + + if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX) { + /* + * work out what the multiplexed fde wants. + */ + mpx_fde = talloc_get_type_abort(fde->additional_data, + struct tevent_fd); + + if (mpx_fde->flags & TEVENT_FD_READ) { + want_read = true; + } + + if (mpx_fde->flags & TEVENT_FD_WRITE) { + want_write = true; + } + } + + /* 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(epoll_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(epoll_ev, fde); + return; + } + + /* there's no epoll_event attached to the fde */ + if (want_read || (want_write && !got_error)) { + epoll_add_event(epoll_ev, fde); + return; + } +} + +/* + Cope with epoll returning EPOLLHUP|EPOLLERR on an event. + Return true if there's nothing else to do, false if + this event needs further handling. +*/ +static bool epoll_handle_hup_or_err(struct epoll_event_context *epoll_ev, + struct tevent_fd *fde) +{ + if (fde == NULL) { + /* Nothing to do if no event. */ + return true; + } + + fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR; + /* + * if we only wait for TEVENT_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)) { + /* + * Do the same as the poll backend and + * remove the writeable flag. + */ + fde->flags &= ~TEVENT_FD_WRITE; + return true; + } + /* This has TEVENT_FD_READ set, we're not finished. */ + return false; +} + +/* + event loop handling using epoll +*/ +static int epoll_event_loop(struct epoll_event_context *epoll_ev, struct timeval *tvalp) +{ + int ret, i; +#define MAXEVENTS 1 + struct epoll_event events[MAXEVENTS]; + int timeout = -1; + int wait_errno; + + if (tvalp) { + /* it's better to trigger timed events a bit later than too early */ + timeout = ((tvalp->tv_usec+999) / 1000) + (tvalp->tv_sec*1000); + } + + if (epoll_ev->ev->signal_events && + tevent_common_check_signal(epoll_ev->ev)) { + return 0; + } + + tevent_trace_point_callback(epoll_ev->ev, TEVENT_TRACE_BEFORE_WAIT); + ret = epoll_wait(epoll_ev->epoll_fd, events, MAXEVENTS, timeout); + wait_errno = errno; + tevent_trace_point_callback(epoll_ev->ev, TEVENT_TRACE_AFTER_WAIT); + + if (ret == -1 && wait_errno == EINTR && epoll_ev->ev->signal_events) { + if (tevent_common_check_signal(epoll_ev->ev)) { + return 0; + } + } + + if (ret == -1 && wait_errno != EINTR) { + epoll_panic(epoll_ev, "epoll_wait() failed", true); + return -1; + } + + if (ret == 0 && tvalp) { + /* we don't care about a possible delay here */ + tevent_common_loop_timer_delay(epoll_ev->ev); + return 0; + } + + for (i=0;i<ret;i++) { + struct tevent_fd *fde = talloc_get_type(events[i].data.ptr, + struct tevent_fd); + uint16_t flags = 0; + struct tevent_fd *mpx_fde = NULL; + + if (fde == NULL) { + epoll_panic(epoll_ev, "epoll_wait() gave bad data", true); + return -1; + } + if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX) { + /* + * Save off the multiplexed event in case we need + * to use it to call the handler function. + */ + mpx_fde = talloc_get_type_abort(fde->additional_data, + struct tevent_fd); + } + if (events[i].events & (EPOLLHUP|EPOLLERR)) { + bool handled_fde = epoll_handle_hup_or_err(epoll_ev, fde); + bool handled_mpx = epoll_handle_hup_or_err(epoll_ev, mpx_fde); + + if (handled_fde && handled_mpx) { + epoll_update_event(epoll_ev, fde); + continue; + } + + if (!handled_mpx) { + /* + * If the mpx event was the one that needs + * further handling, it's the TEVENT_FD_READ + * event so switch over and call that handler. + */ + fde = mpx_fde; + mpx_fde = NULL; + } + flags |= TEVENT_FD_READ; + } + if (events[i].events & EPOLLIN) flags |= TEVENT_FD_READ; + if (events[i].events & EPOLLOUT) flags |= TEVENT_FD_WRITE; + + if (flags & TEVENT_FD_WRITE) { + if (fde->flags & TEVENT_FD_WRITE) { + mpx_fde = NULL; + } + if (mpx_fde && mpx_fde->flags & TEVENT_FD_WRITE) { + fde = mpx_fde; + mpx_fde = NULL; + } + } + + if (mpx_fde) { + /* Ensure we got the right fde. */ + if ((flags & fde->flags) == 0) { + fde = mpx_fde; + mpx_fde = NULL; + } + } + + /* + * make sure we only pass the flags + * the handler is expecting. + */ + flags &= fde->flags; + if (flags) { + return tevent_common_invoke_fd_handler(fde, flags, NULL); + } + } + + return 0; +} + +/* + create a epoll_event_context structure. +*/ +static int epoll_event_context_init(struct tevent_context *ev) +{ + int ret; + struct epoll_event_context *epoll_ev; + + /* + * We might be called during tevent_re_initialise() + * which means we need to free our old additional_data. + */ + TALLOC_FREE(ev->additional_data); + + epoll_ev = talloc_zero(ev, struct epoll_event_context); + if (!epoll_ev) return -1; + epoll_ev->ev = ev; + epoll_ev->epoll_fd = -1; + + ret = epoll_init_ctx(epoll_ev); + if (ret != 0) { + talloc_free(epoll_ev); + return ret; + } + + ev->additional_data = epoll_ev; + return 0; +} + +/* + destroy an fd_event +*/ +static int epoll_event_fd_destructor(struct tevent_fd *fde) +{ + struct tevent_context *ev = fde->event_ctx; + struct epoll_event_context *epoll_ev = NULL; + bool panic_triggered = false; + struct tevent_fd *mpx_fde = NULL; + int flags = fde->flags; + + if (ev == NULL) { + return tevent_common_fd_destructor(fde); + } + + epoll_ev = talloc_get_type_abort(ev->additional_data, + struct epoll_event_context); + + /* + * we must remove the event from the list + * otherwise a panic fallback handler may + * reuse invalid memory + */ + DLIST_REMOVE(ev->fd_events, fde); + + if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX) { + mpx_fde = talloc_get_type_abort(fde->additional_data, + struct tevent_fd); + + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX; + mpx_fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_MPX; + + fde->additional_data = NULL; + mpx_fde->additional_data = NULL; + + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + } + + epoll_ev->panic_state = &panic_triggered; + epoll_check_reopen(epoll_ev); + if (panic_triggered) { + return tevent_common_fd_destructor(fde); + } + + if (mpx_fde != NULL) { + epoll_update_event(epoll_ev, mpx_fde); + if (panic_triggered) { + return tevent_common_fd_destructor(fde); + } + } + + fde->flags = 0; + epoll_update_event(epoll_ev, fde); + fde->flags = flags; + if (panic_triggered) { + return tevent_common_fd_destructor(fde); + } + epoll_ev->panic_state = NULL; + + return tevent_common_fd_destructor(fde); +} + +/* + add a fd based event + return NULL on failure (memory allocation error) +*/ +static struct tevent_fd *epoll_event_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx, + int fd, uint16_t flags, + tevent_fd_handler_t handler, + void *private_data, + const char *handler_name, + const char *location) +{ + struct epoll_event_context *epoll_ev = + talloc_get_type_abort(ev->additional_data, + struct epoll_event_context); + struct tevent_fd *fde; + bool panic_triggered = false; + + fde = tevent_common_add_fd(ev, mem_ctx, fd, flags, + handler, private_data, + handler_name, location); + if (!fde) return NULL; + + talloc_set_destructor(fde, epoll_event_fd_destructor); + + epoll_ev->panic_state = &panic_triggered; + epoll_check_reopen(epoll_ev); + if (panic_triggered) { + return fde; + } + epoll_ev->panic_state = NULL; + + epoll_update_event(epoll_ev, fde); + + return fde; +} + +/* + set the fd event flags +*/ +static void epoll_event_set_fd_flags(struct tevent_fd *fde, uint16_t flags) +{ + struct tevent_context *ev; + struct epoll_event_context *epoll_ev; + bool panic_triggered = false; + + if (fde->flags == flags) return; + + ev = fde->event_ctx; + epoll_ev = talloc_get_type_abort(ev->additional_data, + struct epoll_event_context); + + fde->flags = flags; + + epoll_ev->panic_state = &panic_triggered; + epoll_check_reopen(epoll_ev); + if (panic_triggered) { + return; + } + epoll_ev->panic_state = NULL; + + epoll_update_event(epoll_ev, fde); +} + +/* + do a single event loop using the events defined in ev +*/ +static int epoll_event_loop_once(struct tevent_context *ev, const char *location) +{ + struct epoll_event_context *epoll_ev = + talloc_get_type_abort(ev->additional_data, + struct epoll_event_context); + struct timeval tval; + bool panic_triggered = false; + + if (ev->signal_events && + tevent_common_check_signal(ev)) { + return 0; + } + + if (ev->threaded_contexts != NULL) { + tevent_common_threaded_activate_immediate(ev); + } + + if (ev->immediate_events && + tevent_common_loop_immediate(ev)) { + return 0; + } + + tval = tevent_common_loop_timer_delay(ev); + if (tevent_timeval_is_zero(&tval)) { + return 0; + } + + epoll_ev->panic_state = &panic_triggered; + epoll_ev->panic_force_replay = true; + epoll_check_reopen(epoll_ev); + if (panic_triggered) { + errno = EINVAL; + return -1; + } + epoll_ev->panic_force_replay = false; + epoll_ev->panic_state = NULL; + + return epoll_event_loop(epoll_ev, &tval); +} + +static const struct tevent_ops epoll_event_ops = { + .context_init = epoll_event_context_init, + .add_fd = epoll_event_add_fd, + .set_fd_close_fn = tevent_common_fd_set_close_fn, + .get_fd_flags = tevent_common_fd_get_flags, + .set_fd_flags = epoll_event_set_fd_flags, + .add_timer = tevent_common_add_timer_v2, + .schedule_immediate = tevent_common_schedule_immediate, + .add_signal = tevent_common_add_signal, + .loop_once = epoll_event_loop_once, + .loop_wait = tevent_common_loop_wait, +}; + +_PRIVATE_ bool tevent_epoll_init(void) +{ + return tevent_register_backend("epoll", &epoll_event_ops); +} |