diff options
Diffstat (limited to 'source4/lib/events/events_signal.c')
| -rw-r--r-- | source4/lib/events/events_signal.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/source4/lib/events/events_signal.c b/source4/lib/events/events_signal.c new file mode 100644 index 0000000000..85b42ae4ab --- /dev/null +++ b/source4/lib/events/events_signal.c @@ -0,0 +1,153 @@ +/* + Unix SMB/CIFS implementation. + + common events code for signal events + + Copyright (C) Andrew Tridgell 2007 + + 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 2 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, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include "includes.h" +#include "system/filesys.h" +#include "system/select.h" +#include "lib/util/dlinklist.h" +#include "lib/events/events.h" +#include "lib/events/events_internal.h" + +#define NUM_SIGNALS 64 + +/* + the poor design of signals means that this table must be static global +*/ +static struct { + struct signal_event *sig_handlers[NUM_SIGNALS]; + uint32_t signal_count[NUM_SIGNALS]; + uint32_t got_signal; + int pipe_hack[2]; +} sig_state; + + +/* + signal handler - redirects to registered signals +*/ +static void signal_handler(int signum) +{ + char c = 0; + sig_state.signal_count[signum]++; + sig_state.got_signal++; + /* doesn't matter if this pipe overflows */ + write(sig_state.pipe_hack[1], &c, 1); +} + + +/* + destroy a signal event +*/ +static int signal_event_destructor(struct signal_event *se) +{ + se->event_ctx->num_signal_handlers--; + DLIST_REMOVE(sig_state.sig_handlers[se->signum], se); + if (sig_state.sig_handlers[se->signum] == NULL) { + signal(se->signum, SIG_DFL); + } + return 0; +} + +/* + this is part of the pipe hack needed to avoid the signal race condition +*/ +static void signal_pipe_handler(struct event_context *ev, struct fd_event *fde, + uint16_t flags, void *private) +{ + char c[16]; + /* its non-blocking, doesn't matter if we read too much */ + read(sig_state.pipe_hack[0], c, sizeof(c)); +} + +/* + add a signal event + return NULL on failure (memory allocation error) +*/ +struct signal_event *common_event_add_signal(struct event_context *ev, + TALLOC_CTX *mem_ctx, + int signum, + event_signal_handler_t handler, + void *private_data) +{ + struct signal_event *se; + + if (signum >= NUM_SIGNALS) { + return NULL; + } + + se = talloc(mem_ctx?mem_ctx:ev, struct signal_event); + if (se == NULL) return NULL; + + se->event_ctx = ev; + se->handler = handler; + se->private_data = private_data; + se->signum = signum; + + if (sig_state.sig_handlers[signum] == NULL) { + signal(signum, signal_handler); + } + + DLIST_ADD(sig_state.sig_handlers[signum], se); + + talloc_set_destructor(se, signal_event_destructor); + + if (ev->pipe_fde == NULL) { + if (sig_state.pipe_hack[0] == 0 && + sig_state.pipe_hack[1] == 0) { + pipe(sig_state.pipe_hack); + set_blocking(sig_state.pipe_hack[0], False); + set_blocking(sig_state.pipe_hack[1], False); + } + ev->pipe_fde = event_add_fd(ev, ev, sig_state.pipe_hack[0], + EVENT_FD_READ, signal_pipe_handler, NULL); + } + ev->num_signal_handlers++; + + return se; +} + + +/* + check if a signal is pending + return != 0 if a signal was pending +*/ +int common_event_check_signal(struct event_context *ev) +{ + int i; + if (sig_state.got_signal == 0) { + return 0; + } + + for (i=0;i<NUM_SIGNALS+1;i++) { + uint32_t count = sig_state.signal_count[i]; + if (count != 0) { + struct signal_event *se, *next; + for (se=sig_state.sig_handlers[i];se;se=next) { + next = se->next; + se->handler(ev, se, i, count, se->private_data); + } + sig_state.signal_count[i] -= count; + sig_state.got_signal -= count; + } + } + + return 1; +} |