X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=signal.c;h=0b4b6f0b847171e3c68311c4075c2d26f017a5b3;hp=f8be2f4612002214f669fa74ce92390866b0dc90;hb=8d00849555d99c5434610753ad0e4cc93fb7bb64;hpb=026b8a73a399d13ddb00bd96453747790b40d3ad

diff --git a/signal.c b/signal.c
index f8be2f46..0b4b6f0b 100644
--- a/signal.c
+++ b/signal.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2004-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2004-2010 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -57,8 +57,15 @@ err_out:
  */
 static void generic_signal_handler(int s)
 {
-	write(signal_pipe[1], &s, sizeof(int));
-	//fprintf(stderr, "got sig %i, write returned %d\n", s, ret);
+	ssize_t ret = write(signal_pipe[1], &s, sizeof(int));
+
+	if (ret == sizeof(int))
+		return;
+	if (ret < 0)
+		PARA_EMERG_LOG("%s\n", strerror(errno));
+	else
+		PARA_EMERG_LOG("short write to signal pipe\n");
+	exit(EXIT_FAILURE);
 }
 
 /**
@@ -96,60 +103,72 @@ int para_reap_child(pid_t *pid)
 }
 
 /**
- * Paraslash's zombie killer.
+ * Install the given handler for the given signal.
  *
- * It just calls \p para_reap_child() until there are no more children left to
- * reap.
+ * \param sig The number of the signal to catch.
+ * \param handler to be installed, \p SIG_IGN, or \p SIG_DFL.
+ *
+ * This either succeeds or calls exit(EXIT_FAILURE).
+ *
+ * \sa sigaction(2).
  */
-void para_reap_children(void)
+void para_sigaction(int sig, void (*handler)(int))
 {
-	pid_t pid;
+	struct sigaction act;
 
-	while (para_reap_child(&pid) > 0)
-		; /* nothing */
+	PARA_DEBUG_LOG("catching signal %d\n", sig);
+	act.sa_handler = handler;
+	sigemptyset(&act.sa_mask);
+	act.sa_flags = 0;
+	if (sig == SIGALRM) {
+		#ifdef SA_INTERRUPT /* SunOS */
+			act.sa_flags |= SA_INTERRUPT;
+		#endif
+	} else {
+		#ifdef SA_RESTART /* BSD */
+			act.sa_flags |= SA_RESTART;
+		#endif
+	}
+	if (sigaction(sig, &act, NULL) >= 0)
+		return;
+	PARA_EMERG_LOG("failed to install signal handler for signal %d\n",
+		sig);
+	exit(EXIT_FAILURE);
 }
 
 /**
- * Wrapper around signal(2).
+ * Install the generic signal handler for the given signal number.
  *
  * \param sig The number of the signal to catch.
  *
- * This installs the generic signal handler for the given signal.
- *
- * \return This function returns 1 on success and \p -E_SIGNAL_SIG_ERR on errors.
- *
- * \sa signal(2).
+ * \sa signal(2), sigaction(2).
  */
-int para_install_sighandler(int sig)
+void para_install_sighandler(int sig)
 {
-	PARA_DEBUG_LOG("catching signal %d\n", sig);
-	return signal(sig, &generic_signal_handler) == SIG_ERR?  -E_SIGNAL_SIG_ERR : 1;
+	para_sigaction(sig, &generic_signal_handler);
 }
 
 /**
- * Return the number of next pending signal.
+ * Return the number of the next pending signal.
  *
- * This should be called if the fd for the signal pipe is ready for reading.
+ * \param rfds Th fd_set containing the signal pipe.
  *
- * \return On success, the number of the received signal is returned.  If the
- * read returned zero or was interrupted by another signal the function returns
- * 0.  Otherwise, a negative error value is returned.
+ * \return On success, the number of the received signal is returned. If there
+ * is no signal currently pending, the function returns zero. On read errors
+ * from the signal pipe, the process is terminated.
  */
-int para_next_signal(void)
+int para_next_signal(fd_set *rfds)
 {
-	int s;
-	ssize_t r = read(signal_pipe[0], &s, sizeof(s));
+	size_t n;
+	int s, ret = read_nonblock(signal_pipe[0], &s, sizeof(s), rfds, &n);
 
-	if (!r) {
-		PARA_CRIT_LOG("read from signal pipe returned zero\n");
-		return 0;
-	}
-	if (r < 0) {
-		if (errno == EAGAIN || errno == EINTR)
-			return 0;
-		return -ERRNO_TO_PARA_ERROR(errno);
+	if (ret < 0) {
+		PARA_EMERG_LOG("%s\n", para_strerror(-ret));
+		exit(EXIT_FAILURE);
 	}
-	assert(r == sizeof(s));
+	if (n == 0)
+		return 0;
+	assert(n == sizeof(s));
 	PARA_DEBUG_LOG("next signal: %d\n", s);
 	return s;
 }