X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=daemon.c;h=20cdc6ae605a99f56f35bf41f0abeff7d508936d;hp=478b0f47acc94d3098cc17576599032f007b43ca;hb=fc8dfbb416ff07cca08fbf4e13efcaa25e17cc54;hpb=642445e95fea1c548c79f80ad3b5d6f30ba572f3

diff --git a/daemon.c b/daemon.c
index 478b0f47..20cdc6ae 100644
--- a/daemon.c
+++ b/daemon.c
@@ -54,12 +54,12 @@ static void daemon_set_default_log_colors(void)
 		color_parse_or_die(default_log_colors[i], me->log_colors[i]);
 }
 
-/*
+/**
  * Set the color for one loglevel.
  *
- * arg must be of the form "ll:[fg [bg]] [attr]".
+ * \param arg Must be of the form "ll:[fg [bg]] [attr]".
  */
-static void daemon_set_log_color_or_die(char const *arg)
+void daemon_set_log_color_or_die(const char *arg)
 {
 	char *p = strchr(arg, ':');
 	int ret, ll;
@@ -74,7 +74,7 @@ static void daemon_set_log_color_or_die(char const *arg)
 	color_parse_or_die(p, me->log_colors[ll]);
 	return;
 err:
-	PARA_EMERG_LOG("%s: color syntax error\n", arg);
+	PARA_EMERG_LOG("%s: invalid color argument\n", arg);
 	exit(EXIT_FAILURE);
 }
 
@@ -85,36 +85,31 @@ err:
  * \param color_arg_auto The value for automatic color detection.
  * \param color_arg_no The value to disable colored log messages.
  * \param logfile_given In auto mode colors are disabled if this value is true.
- * \param log_color_argv Color specifiers given to --log-color.
- * \param argc Number of color specifiers in \a log_color_argv.
  *
- * If \a color_arg equals \a color_arg_no, color mode is disabled, i.e., calls
- * to \a para_log() will not produce colored output. If \a color_arg == \a
- * color_arg_auto, the function autodetects whether to activate colors.
- * Otherwise color mode is enabled.
+ * If color_arg equals color_arg_no, color mode is disabled. That is, calls to
+ * para_log() will not produce colored output. If color_arg equals
+ * color_arg_auto, the function detects automatically whether to activate
+ * colors. Otherwise color mode is enabled.
+ *
+ * If color mode is to be enabled, the default colors are set for each
+ * loglevel. They can be overwritten by calling daemon_set_log_color_or_die().
  *
- * If color mode is to be enabled, the strings in \a log_color_argv are parsed
- * and the color scheme is updated accordingly. For each loglevel, the default
- * colors apply if there is no log_color_argv for this loglevel.
+ * \return Whether colors have been enabled by the function.
  */
-void daemon_init_colors_or_die(int color_arg, int color_arg_auto,
-		int color_arg_no, bool logfile_given, char **log_color_argv,
-		int argc)
+bool daemon_init_colors_or_die(int color_arg, int color_arg_auto,
+		int color_arg_no, bool logfile_given)
 {
-	int i;
-
 	if (color_arg == color_arg_no)
-		return;
+		return false;
 	if (color_arg == color_arg_auto) {
 		if (logfile_given)
-			return;
+			return false;
 		if (!isatty(STDERR_FILENO))
-			return;
+			return false;
 	}
 	daemon_set_flag(DF_COLOR_LOG);
 	daemon_set_default_log_colors();
-	for (i = 0; i < argc; i++)
-		daemon_set_log_color_or_die(log_color_argv[i]);
+	return true;
 }
 
 /**
@@ -122,7 +117,7 @@ void daemon_init_colors_or_die(int color_arg, int color_arg_auto,
  *
  * \param logfile_name The full path of the logfile.
  */
-void daemon_set_logfile(char *logfile_name)
+void daemon_set_logfile(const char *logfile_name)
 {
 	free(me->logfile_name);
 	me->logfile_name = NULL;
@@ -135,7 +130,7 @@ void daemon_set_logfile(char *logfile_name)
  *
  * \param loglevel The smallest level that should be logged.
  */
-void daemon_set_loglevel(char *loglevel)
+void daemon_set_loglevel(const char *loglevel)
 {
 	int ret = get_loglevel_by_name(loglevel);
 
@@ -160,10 +155,6 @@ static bool daemon_test_flag(unsigned flag)
 	return me->flags & flag;
 }
 
-static void dummy_sighandler(__a_unused int s)
-{
-}
-
 /**
  * Do the usual stuff to become a daemon.
  *
@@ -171,30 +162,42 @@ static void dummy_sighandler(__a_unused int s)
  *
  * Fork, become session leader, cd to /, and dup fd 0, 1, 2 to /dev/null. If \a
  * parent_waits is false, the parent process terminates immediately.
- * Otherwise, it calls pause() to sleep until it receives \p SIGTERM or \p
- * SIGCHLD and exits successfully thereafter. This behaviour is useful if the
- * daemon process should not detach from the console until the child process
- * has completed its setup.
+ * Otherwise, a pipe is created prior to the fork() and the parent tries to
+ * read a single byte from the reading end of the pipe. The child is supposed
+ * to write to the writing end of the pipe after it completed its setup
+ * procedure successfully. This behaviour is useful to let the parent process
+ * die with an error if the child process aborts early, since in this case the
+ * read() will return non-positive.
+ *
+ * \return This function either succeeds or calls exit(3). If parent_waits is
+ * true, the return value is the file descriptor of the writing end of the
+ * pipe. Otherwise the function returns zero.
  *
  * \sa fork(2), setsid(2), dup(2), pause(2).
  */
-void daemonize(bool parent_waits)
+int daemonize(bool parent_waits)
 {
 	pid_t pid;
-	int null;
+	int null, pipe_fd[2];
 
-	PARA_INFO_LOG("daemonizing\n");
+	if (parent_waits && pipe(pipe_fd) < 0)
+		goto err;
+	PARA_INFO_LOG("subsequent log messages go to %s\n", me->logfile_name?
+		 me->logfile_name : "/dev/null");
 	pid = fork();
 	if (pid < 0)
 		goto err;
-	if (pid) {
+	if (pid) { /* parent exits */
 		if (parent_waits) {
-			signal(SIGTERM, dummy_sighandler);
-			signal(SIGCHLD, dummy_sighandler);
-			pause();
+			char c;
+			close(pipe_fd[1]);
+			exit(read(pipe_fd[0], &c, 1) <= 0?
+				EXIT_FAILURE : EXIT_SUCCESS);
 		}
-		exit(EXIT_SUCCESS); /* parent exits */
+		exit(EXIT_SUCCESS);
 	}
+	if (parent_waits)
+		close(pipe_fd[0]);
 	/* become session leader */
 	if (setsid() < 0)
 		goto err;
@@ -210,7 +213,7 @@ void daemonize(bool parent_waits)
 	if (dup2(null, STDERR_FILENO) < 0)
 		goto err;
 	close(null);
-	return;
+	return parent_waits? pipe_fd[1] : 0;
 err:
 	PARA_EMERG_LOG("fatal: %s\n", strerror(errno));
 	exit(EXIT_FAILURE);