mirror of
https://github.com/openvswitch/ovs
synced 2025-10-17 14:28:02 +00:00
145 lines
3.7 KiB
C
145 lines
3.7 KiB
C
/*
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* Copyright (c) 2008, 2009, 2011, 2012, 2013 Nicira, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include "signals.h"
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#include <errno.h>
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#include <limits.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "poll-loop.h"
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#include "socket-util.h"
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#include "type-props.h"
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#include "util.h"
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#include "vlog.h"
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VLOG_DEFINE_THIS_MODULE(signals);
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#if defined(_NSIG)
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#define N_SIGNALS _NSIG
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#elif defined(NSIG)
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#define N_SIGNALS NSIG
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#else
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/* We could try harder to get the maximum signal number, but in practice we
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* only care about SIGHUP, which is normally signal 1 anyway. */
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#define N_SIGNALS 32
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#endif
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struct signal {
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int fds[2];
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};
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static struct signal signals[N_SIGNALS];
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static void signal_handler(int signr);
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/* Sets up a handler for 'signr' and returns a structure that represents it.
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*
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* Only one handler for a given signal may be registered. */
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struct signal *
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signal_register(int signr)
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{
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struct sigaction sa;
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struct signal *s;
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ovs_assert(signr >= 1 && signr < N_SIGNALS);
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/* Create a pipe. */
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s = &signals[signr];
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ovs_assert(!s->fds[0] && !s->fds[1]);
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xpipe_nonblocking(s->fds);
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/* Install signal handler. */
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memset(&sa, 0, sizeof sa);
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sa.sa_handler = signal_handler;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_RESTART;
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xsigaction(signr, &sa, NULL);
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return s;
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}
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/* Returns true if signal 's' has been received since the last call to this
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* function with argument 's'. */
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bool
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signal_poll(struct signal *s)
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{
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char buf[_POSIX_PIPE_BUF];
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return read(s->fds[0], buf, sizeof buf) > 0;
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}
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/* Causes the next call to poll_block() to wake up when signal_poll(s) would
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* return true. */
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void
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signal_wait(struct signal *s)
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{
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poll_fd_wait(s->fds[0], POLLIN);
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}
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static void
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signal_handler(int signr)
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{
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if (signr >= 1 && signr < N_SIGNALS) {
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ignore(write(signals[signr].fds[1], "", 1));
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}
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}
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/* Returns the name of signal 'signum' as a string. The return value is either
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* a statically allocated constant string or the 'bufsize'-byte buffer
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* 'namebuf'. 'bufsize' should be at least SIGNAL_NAME_BUFSIZE.
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*
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* The string is probably a (possibly multi-word) description of the signal
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* (e.g. "Hangup") instead of just the stringified version of the macro
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* (e.g. "SIGHUP"). */
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const char *
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signal_name(int signum, char *namebuf, size_t bufsize)
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{
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#if HAVE_DECL_SYS_SIGLIST
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if (signum >= 0 && signum < ARRAY_SIZE(sys_siglist)) {
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const char *name = sys_siglist[signum];
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if (name) {
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return name;
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}
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}
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#endif
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snprintf(namebuf, bufsize, "signal %d", signum);
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return namebuf;
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}
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void
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xsigaction(int signum, const struct sigaction *new, struct sigaction *old)
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{
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if (sigaction(signum, new, old)) {
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char namebuf[SIGNAL_NAME_BUFSIZE];
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VLOG_FATAL("sigaction(%s) failed (%s)",
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signal_name(signum, namebuf, sizeof namebuf),
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ovs_strerror(errno));
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}
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}
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void
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xpthread_sigmask(int how, const sigset_t *new, sigset_t *old)
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{
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int error = pthread_sigmask(how, new, old);
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if (error) {
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VLOG_FATAL("pthread_sigmask failed (%s)", ovs_strerror(error));
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}
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}
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