diff options
Diffstat (limited to 'tevent_epoll.c')
| -rw-r--r-- | tevent_epoll.c | 945 |
1 files changed, 945 insertions, 0 deletions
diff --git a/tevent_epoll.c b/tevent_epoll.c new file mode 100644 index 0000000..e56bd02 --- /dev/null +++ b/tevent_epoll.c @@ -0,0 +1,945 @@ +/* + 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_create1(2) */ + 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_GOT_ERROR (1<<1) + +#ifdef TEST_PANIC_FALLBACK + +static int epoll_create1_panic_fallback(struct epoll_event_context *epoll_ev, + int flags) +{ + if (epoll_ev->panic_fallback == NULL) { + return epoll_create1(flags); + } + + /* 50% of the time, fail... */ + if ((random() % 2) == 0) { + errno = EINVAL; + return -1; + } + + return epoll_create1(flags); +} + +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_create1(_flags) \ + epoll_create1_panic_fallback(epoll_ev, _flags) +#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; + + /* + * we do not need to specify EPOLLERR | EPOLLHUP + * they are always reported. + */ + + if (flags & TEVENT_FD_READ) { + /* + * Note that EPOLLRDHUP always + * returns EPOLLIN in addition, + * so EPOLLRDHUP is not strictly needed, + * but we want to make it explicit. + */ + ret |= EPOLLIN | EPOLLRDHUP; + } + if (flags & TEVENT_FD_WRITE) { + ret |= EPOLLOUT; + } + if (flags & TEVENT_FD_ERROR) { + ret |= EPOLLRDHUP; + } + 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_create1(EPOLL_CLOEXEC); + if (epoll_ev->epoll_fd == -1) { + tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL, + "Failed to create epoll handle (%s).\n", + strerror(errno)); + return -1; + } + + 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_create1(EPOLL_CLOEXEC); + if (epoll_ev->epoll_fd == -1) { + epoll_panic(epoll_ev, "epoll_create() failed", false); + return; + } + + epoll_ev->pid = pid; + epoll_ev->panic_state = &panic_triggered; + for (fde=epoll_ev->ev->fd_events;fde;fde=fde->next) { + /* + * We leave the mpx mappings alive + * so that we'll just re-add events for + * the existing primary events in the loop + * below. + */ + fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + } + for (fde=epoll_ev->ev->fd_events;fde;fde=fde->next) { + 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 poll 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 tevent_fd *primary = NULL; + uint16_t effective_flags; + struct epoll_event event; + uint64_t clear_flags = 0; + uint64_t add_flags = 0; + int ret; + + /* + * Check if there is another fde we can attach to + */ + primary = tevent_common_fd_mpx_add(add_fde); + if (primary == NULL) { + /* the caller calls epoll_panic() */ + return -1; + } + + /* + * First propagate the HAS_EVENT flag from + * the primary to all others (mainly add_fde) + */ + if (primary->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT) { + add_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + tevent_common_fd_mpx_additional_flags(primary, 0, add_flags); + } + + /* + * Update the mpx internals and check if + * there is an update needed. + */ + primary = tevent_common_fd_mpx_update(primary); + if (primary == NULL) { + /* + * It seems the primary was already + * watching (at least) the same flags + * as add_fde, so we are done. + */ + return 0; + } + + /* + * Before me modify the low level epoll state, + * we clear HAS_EVENT on all fdes. + */ + clear_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + tevent_common_fd_mpx_additional_flags(primary, clear_flags, 0); + + effective_flags = tevent_common_fd_mpx_flags(primary); + + /* + * Modify the low level epoll state to reflect + * the effective flags we want to monitor. + */ + ZERO_STRUCT(event); + event.events = epoll_map_flags(effective_flags); + event.data.ptr = primary; + ret = epoll_ctl(epoll_ev->epoll_fd, + EPOLL_CTL_MOD, + primary->fd, + &event); + if (ret != 0 && errno == EBADF) { + struct tevent_common_fd_buf pbuf = {}; + TEVENT_DEBUG(epoll_ev->ev, TEVENT_DEBUG_ERROR, + "EPOLL_CTL_MOD EBADF for " + "%s - disabling\n", + tevent_common_fd_str(&pbuf, "primary", primary)); + tevent_common_fd_mpx_disarm_all(primary); + return 0; + } else if (ret != 0) { + struct tevent_common_fd_buf pbuf = {}; + TEVENT_DEBUG(epoll_ev->ev, TEVENT_DEBUG_FATAL, + "EPOLL_CTL_MOD for %s - failed - %s", + tevent_common_fd_str(&pbuf, "primary", primary), + strerror(errno)); + /* the caller calls epoll_panic() */ + return ret; + } + + /* + * Finally re-add HAS_EVENT to all fdes + */ + add_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + tevent_common_fd_mpx_additional_flags(primary, 0, add_flags); + + 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 *_primary) +{ + struct tevent_fd *primary = tevent_common_fd_mpx_primary(_primary); + uint16_t effective_flags = tevent_common_fd_mpx_flags(primary); + struct epoll_event event; + uint64_t clear_flags = 0; + uint64_t add_flags = 0; + int ret; + + /* + * Before me modify the low level epoll state, + * we clear HAS_EVENT on all fdes. + */ + clear_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + tevent_common_fd_mpx_additional_flags(primary, clear_flags, 0); + + /* + * Modify the low level epoll state to reflect + * the effective flags we want to monitor. + * + * Most likely we won't trigger the EEXIST + * case, so it's much cheaper to try and + * react on EEXIST if needed, than to always + * scan the list of all existing events. + */ + ZERO_STRUCT(event); + event.events = epoll_map_flags(effective_flags); + event.data.ptr = primary; + ret = epoll_ctl(epoll_ev->epoll_fd, + EPOLL_CTL_ADD, + primary->fd, + &event); + if (ret != 0 && errno == EBADF) { + struct tevent_common_fd_buf pbuf = {}; + TEVENT_DEBUG(epoll_ev->ev, TEVENT_DEBUG_ERROR, + "EPOLL_CTL_ADD EBADF for " + "%s - disabling\n", + tevent_common_fd_str(&pbuf, "primary", primary)); + tevent_common_fd_mpx_disarm_all(primary); + return; + } else if (ret != 0 && errno == EEXIST) { + ret = epoll_add_multiplex_fd(epoll_ev, primary); + if (ret != 0) { + epoll_panic(epoll_ev, "epoll_add_multiplex_fd failed", + false); + return; + } + /* + * epoll_add_multiplex_fd() already + * added EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT + */ + return; + } else if (ret != 0) { + epoll_panic(epoll_ev, "EPOLL_CTL_ADD failed", false); + return; + } + + /* + * Finally re-add HAS_EVENT to all fdes + */ + add_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + tevent_common_fd_mpx_additional_flags(primary, 0, add_flags); +} + +/* + delete the epoll event for given fd_event +*/ +static void epoll_del_event(struct epoll_event_context *epoll_ev, + struct tevent_fd *_primary) +{ + struct tevent_fd *primary = tevent_common_fd_mpx_primary(_primary); + struct epoll_event event; + uint64_t clear_flags = 0; + int ret; + + /* + * Before me delete the low level epoll state, + * we clear HAS_EVENT on all fdes. + */ + clear_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + tevent_common_fd_mpx_additional_flags(primary, clear_flags, 0); + + /* + * Delete the low level epoll state to reflect + * the effective flags we want to monitor. + */ + ZERO_STRUCT(event); + ret = epoll_ctl(epoll_ev->epoll_fd, + EPOLL_CTL_DEL, + primary->fd, + &event); + if (ret != 0 && errno == ENOENT) { + struct tevent_common_fd_buf pbuf = {}; + /* + * 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 %s\n", + tevent_common_fd_str(&pbuf, "primary", primary)); + return; + } else if (ret != 0 && errno == EBADF) { + struct tevent_common_fd_buf pbuf = {}; + TEVENT_DEBUG(epoll_ev->ev, TEVENT_DEBUG_WARNING, + "EPOLL_CTL_DEL EBADF for %s - disabling\n", + tevent_common_fd_str(&pbuf, "primary", primary)); + tevent_common_fd_mpx_disarm_all(primary); + return; + } else if (ret != 0) { + struct tevent_common_fd_buf pbuf = {}; + TEVENT_DEBUG(epoll_ev->ev, TEVENT_DEBUG_FATAL, + "EPOLL_CTL_DEL for %s - failed - %s", + tevent_common_fd_str(&pbuf, "primary", primary), + strerror(errno)); + 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 *_primary) +{ + struct tevent_fd *primary = tevent_common_fd_mpx_primary(_primary); + uint16_t effective_flags = tevent_common_fd_mpx_flags(primary); + struct epoll_event event; + uint64_t clear_flags = 0; + uint64_t add_flags = 0; + int ret; + + /* + * Before me modify the low level epoll state, + * we clear HAS_EVENT on all fdes. + */ + clear_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + tevent_common_fd_mpx_additional_flags(primary, clear_flags, 0); + + /* + * Modify the low level epoll state to reflect + * the effective flags we want to monitor. + */ + ZERO_STRUCT(event); + event.events = epoll_map_flags(effective_flags); + event.data.ptr = primary; + ret = epoll_ctl(epoll_ev->epoll_fd, + EPOLL_CTL_MOD, + primary->fd, + &event); + if (ret != 0 && errno == EBADF) { + struct tevent_common_fd_buf pbuf = {}; + TEVENT_DEBUG(epoll_ev->ev, TEVENT_DEBUG_ERROR, + "EPOLL_CTL_MOD EBADF for %s - disabling\n", + tevent_common_fd_str(&pbuf, "primary", primary)); + tevent_common_fd_mpx_disarm_all(primary); + return; + } else if (ret != 0) { + struct tevent_common_fd_buf pbuf = {}; + TEVENT_DEBUG(epoll_ev->ev, TEVENT_DEBUG_FATAL, + "EPOLL_CTL_MOD for %s - failed - %s", + tevent_common_fd_str(&pbuf, "primary", primary), + strerror(errno)); + epoll_panic(epoll_ev, "EPOLL_CTL_MOD failed", false); + return; + } + + /* + * Finally re-add HAS_EVENT to all fdes + */ + add_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT; + tevent_common_fd_mpx_additional_flags(primary, 0, add_flags); +} + +static void epoll_update_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde) +{ + struct tevent_fd *primary = tevent_common_fd_mpx_primary(fde); + uint64_t _paf = primary->additional_flags; + bool got_error = (_paf & EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR); + uint16_t effective_flags = tevent_common_fd_mpx_flags(primary); + bool want_read = (effective_flags & TEVENT_FD_READ); + bool want_write= (effective_flags & TEVENT_FD_WRITE); + bool want_error= (effective_flags & TEVENT_FD_ERROR); + + /* there's already an event */ + if (primary->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT) { + if (want_read || want_error || (want_write && !got_error)) { + epoll_mod_event(epoll_ev, primary); + 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, primary); + return; + } + + /* there's no epoll_event attached to the fde */ + if (want_read || want_error || (want_write && !got_error)) { + epoll_add_event(epoll_ev, primary); + return; + } +} + +/* + 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); + struct tevent_fd *selected = NULL; + uint16_t effective_flags; + uint16_t flags = 0; + bool got_error = false; + + if (fde == NULL) { + epoll_panic(epoll_ev, "epoll_wait() gave bad data", true); + return -1; + } + effective_flags = tevent_common_fd_mpx_flags(fde); + if (events[i].events & (EPOLLHUP|EPOLLERR|EPOLLRDHUP)) { + uint64_t add_flags = 0; + + add_flags |= EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR; + tevent_common_fd_mpx_additional_flags(fde, + 0, + add_flags); + + if (effective_flags & TEVENT_FD_ERROR) { + flags |= TEVENT_FD_ERROR; + } + if (effective_flags & TEVENT_FD_READ) { + flags |= TEVENT_FD_READ; + } + } + if (events[i].events & EPOLLIN) { + if (effective_flags & TEVENT_FD_READ) { + flags |= TEVENT_FD_READ; + } + } + if (events[i].events & EPOLLOUT) { + if (effective_flags & TEVENT_FD_WRITE) { + flags |= TEVENT_FD_WRITE; + } + } + + if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR) + { + got_error = true; + } + + selected = tevent_common_fd_mpx_select(fde, flags, got_error); + if (selected == NULL) { + if (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 + * + * Do the same as the poll backend and + * remove the writeable flag. + */ + tevent_common_fd_mpx_clear_writeable(fde); + epoll_update_event(epoll_ev, fde); + } + continue; + } + + /* + * make sure we only pass the flags + * the handler is expecting. + */ + flags &= selected->flags; + return tevent_common_invoke_fd_handler(selected, + 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_fd *old_primary = NULL; + struct tevent_fd *new_primary = NULL; + struct tevent_fd *update_primary = NULL; + struct tevent_context *ev = fde->event_ctx; + struct epoll_event_context *epoll_ev = NULL; + bool panic_triggered = false; + + if (ev == NULL) { + tevent_common_fd_mpx_reinit(fde); + 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); + + epoll_ev->panic_state = &panic_triggered; + if (epoll_ev->pid != tevent_cached_getpid()) { + epoll_check_reopen(epoll_ev); + if (panic_triggered) { + tevent_common_fd_mpx_reinit(fde); + return tevent_common_fd_destructor(fde); + } + } + + old_primary = tevent_common_fd_mpx_primary(fde); + + if (old_primary == fde) { + epoll_del_event(epoll_ev, fde); + if (panic_triggered) { + tevent_common_fd_mpx_reinit(fde); + return tevent_common_fd_destructor(fde); + } + } + + new_primary = tevent_common_fd_mpx_remove(fde); + if (new_primary == NULL) { + epoll_ev->panic_state = NULL; + return tevent_common_fd_destructor(fde); + } + update_primary = tevent_common_fd_mpx_update(new_primary); + if (update_primary == NULL) { + epoll_ev->panic_state = NULL; + return tevent_common_fd_destructor(fde); + } + + epoll_update_event(epoll_ev, update_primary); + 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; + pid_t old_pid = epoll_ev->pid; + + 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); + + /* + * prepare for tevent_common_fd_mpx_flags() + * in epoll_update_event() + */ + tevent_common_fd_mpx_update_flags(fde); + + if (epoll_ev->pid != tevent_cached_getpid()) { + epoll_ev->panic_state = &panic_triggered; + epoll_check_reopen(epoll_ev); + if (panic_triggered) { + return fde; + } + epoll_ev->panic_state = NULL; + } + + if (epoll_ev->pid == old_pid) { + 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; + pid_t old_pid; + + if (fde->flags == flags) return; + + ev = fde->event_ctx; + epoll_ev = talloc_get_type_abort(ev->additional_data, + struct epoll_event_context); + old_pid = epoll_ev->pid; + + fde->flags = flags; + /* + * prepare for tevent_common_fd_mpx_flags() + * in epoll_update_event() + */ + tevent_common_fd_mpx_update_flags(fde); + + if (epoll_ev->pid != tevent_cached_getpid()) { + epoll_ev->panic_state = &panic_triggered; + epoll_check_reopen(epoll_ev); + if (panic_triggered) { + return; + } + epoll_ev->panic_state = NULL; + } + + if (epoll_ev->pid == old_pid) { + 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; + } + + if (epoll_ev->pid != tevent_cached_getpid()) { + 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); +} |