#endif
struct signal {
- struct sigaction saved_sa;
- int signr;
+ int fds[2];
};
-static volatile sig_atomic_t signaled[N_SIGNALS];
-
-static int fds[2];
+static struct signal signals[N_SIGNALS];
static void signal_handler(int signr);
-/* Initializes the signals subsystem (if it is not already initialized). Calls
- * exit() if initialization fails.
- *
- * Calling this function is optional; it will be called automatically by
- * signal_start() if necessary. Calling it explicitly allows the client to
- * prevent the process from exiting at an unexpected time. */
-void
-signal_init(void)
-{
- static bool inited;
- if (!inited) {
- inited = true;
- xpipe_nonblocking(fds);
- }
-}
-
/* Sets up a handler for 'signr' and returns a structure that represents it.
*
- * Only one handler for a given signal may be registered at a time. */
+ * Only one handler for a given signal may be registered. */
struct signal *
signal_register(int signr)
{
struct sigaction sa;
struct signal *s;
- signal_init();
+ ovs_assert(signr >= 1 && signr < N_SIGNALS);
- s = xmalloc(sizeof *s);
- s->signr = signr;
+ /* Create a pipe. */
+ s = &signals[signr];
+ ovs_assert(!s->fds[0] && !s->fds[1]);
+ xpipe_nonblocking(s->fds);
- /* Set up signal handler. */
- ovs_assert(signr >= 1 && signr < N_SIGNALS);
+ /* Install signal handler. */
memset(&sa, 0, sizeof sa);
sa.sa_handler = signal_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
- xsigaction(signr, &sa, &s->saved_sa);
+ xsigaction(signr, &sa, NULL);
return s;
}
-/* Unregisters the handler for 's', restores the signal handler that was in
- * effect before signal_register() was called, and frees 's'. */
-void
-signal_unregister(struct signal *s)
-{
- if (s) {
- xsigaction(s->signr, &s->saved_sa, NULL);
- free(s);
- }
-}
-
/* Returns true if signal 's' has been received since the last call to this
* function with argument 's'. */
bool
signal_poll(struct signal *s)
{
char buf[_POSIX_PIPE_BUF];
- ignore(read(fds[0], buf, sizeof buf));
- if (signaled[s->signr]) {
- signaled[s->signr] = 0;
- return true;
- }
- return false;
+
+ return read(s->fds[0], buf, sizeof buf) > 0;
}
/* Causes the next call to poll_block() to wake up when signal_poll(s) would
void
signal_wait(struct signal *s)
{
- if (signaled[s->signr]) {
- poll_immediate_wake();
- } else {
- poll_fd_wait(fds[0], POLLIN);
- }
+ poll_fd_wait(s->fds[0], POLLIN);
}
\f
static void
signal_handler(int signr)
{
if (signr >= 1 && signr < N_SIGNALS) {
- ignore(write(fds[1], "", 1));
- signaled[signr] = true;
+ ignore(write(signals[signr].fds[1], "", 1));
}
}
-/* Returns the name of signal 'signum' as a string. The string may be in a
- * static buffer that is reused from one call to the next.
+/* Returns the name of signal 'signum' as a string. The return value is either
+ * a statically allocated constant string or the 'bufsize'-byte buffer
+ * 'namebuf'. 'bufsize' should be at least SIGNAL_NAME_BUFSIZE.
*
* The string is probably a (possibly multi-word) description of the signal
* (e.g. "Hangup") instead of just the stringified version of the macro
* (e.g. "SIGHUP"). */
const char *
-signal_name(int signum)
+signal_name(int signum, char *namebuf, size_t bufsize)
{
- const char *name = NULL;
-#ifdef HAVE_STRSIGNAL
- name = strsignal(signum);
-#endif
- if (!name) {
- static char buffer[7 + INT_STRLEN(int) + 1];
- sprintf(buffer, "signal %d", signum);
- name = buffer;
+#if HAVE_DECL_SYS_SIGLIST
+ if (signum >= 0 && signum < N_SIGNALS) {
+ const char *name = sys_siglist[signum];
+ if (name) {
+ return name;
+ }
}
- return name;
+#endif
+
+ snprintf(namebuf, bufsize, "signal %d", signum);
+ return namebuf;
}
void
xsigaction(int signum, const struct sigaction *new, struct sigaction *old)
{
if (sigaction(signum, new, old)) {
+ char namebuf[SIGNAL_NAME_BUFSIZE];
+
VLOG_FATAL("sigaction(%s) failed (%s)",
- signal_name(signum), strerror(errno));
+ signal_name(signum, namebuf, sizeof namebuf),
+ ovs_strerror(errno));
}
}
{
int error = pthread_sigmask(how, new, old);
if (error) {
- VLOG_FATAL("pthread_sigmask failed (%s)", strerror(error));
+ VLOG_FATAL("pthread_sigmask failed (%s)", ovs_strerror(error));
}
}