diff options
| -rw-r--r-- | lib/tevent/tevent_epoll.c | 97 |
1 files changed, 96 insertions, 1 deletions
diff --git a/lib/tevent/tevent_epoll.c b/lib/tevent/tevent_epoll.c index adea677096..c2b743dcd1 100644 --- a/lib/tevent/tevent_epoll.c +++ b/lib/tevent/tevent_epoll.c @@ -4,7 +4,8 @@ main select loop and event handling - epoll implementation Copyright (C) Andrew Tridgell 2003-2005 - Copyright (C) Stefan Metzmacher 2005-2009 + 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 @@ -48,6 +49,7 @@ struct epoll_event_context { #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 @@ -264,6 +266,99 @@ static void epoll_check_reopen(struct epoll_event_context *epoll_ev) } /* + 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->event_ctx = NULL; + DLIST_REMOVE(epoll_ev->ev->fd_events, add_fde); + 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) |