main: add --debug, fix logging under systemd

When run with --no-daemon, NM used to duplicate all syslog output to
stderr, for ease of debugging. But this meant it had to tell systemd
to ignore stderr, so you wouldn't get duplicated log entries. But that
meant we lost error messages that didn't go through nm_log. (eg,
g_warning()s and g_return_if_fail()s).

Fix this by making --no-daemon no longer duplicate syslog output to
stderr, and removing the "StandardError=null" from the systemd service
file. To get the old behavior, you can use --debug instead of
--no-daemon.

https://bugzilla.gnome.org/show_bug.cgi?id=700550

data/NetworkManager.service.in

@@ -8,10 +8,6 @@ Before=network.target
 Type=dbus
 BusName=org.freedesktop.NetworkManager
 ExecStart=@sbindir@/NetworkManager --no-daemon
-# Suppress stderr to eliminate duplicated messages in syslog. NM calls openlog()
-# with LOG_PERROR when run in foreground. But systemd redirects stderr to
-# syslog by default, which results in logging each message twice.
-StandardError=null
 # NM doesn't want systemd to kill its children for it
 KillMode=process
 

man/NetworkManager.xml

@@ -137,9 +137,13 @@
       </varlistentry>
       <varlistentry>
 	<term><option>--no-daemon</option></term>
-	<listitem><para>Do not daemonize.  This is useful for
-	debugging, and directs log output to the controlling terminal
-	in addition to syslog.
+	<listitem><para>Do not daemonize.
+	</para></listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><option>--debug</option></term>
+	<listitem><para>Do not daemonize, and direct log output to the
+	controlling terminal in addition to syslog.
 	</para></listitem>
       </varlistentry>
       <varlistentry>

src/logging/nm-logging.c

@@ -349,12 +349,12 @@ nm_log_handler (const gchar *log_domain,
 }
 
 void
-nm_logging_start (gboolean become_daemon)
+nm_logging_start (gboolean debug)
 {
-	if (become_daemon)
-		openlog (G_LOG_DOMAIN, LOG_PID, LOG_DAEMON);
-	else
+	if (debug)
 		openlog (G_LOG_DOMAIN, LOG_CONS | LOG_PERROR | LOG_PID, LOG_USER);
+	else
+		openlog (G_LOG_DOMAIN, LOG_PID, LOG_DAEMON);
 
 	g_log_set_handler (G_LOG_DOMAIN, 
 	                   G_LOG_LEVEL_MASK | G_LOG_FLAG_FATAL | G_LOG_FLAG_RECURSION,

src/logging/nm-logging.h

@@ -123,7 +123,7 @@ const char *nm_logging_all_domains_to_string (void);
 #undef nm_error_str
 
 gboolean nm_logging_setup     (const char *level, const char *domains, GError **error);
-void     nm_logging_start     (gboolean become_daemon);
+void     nm_logging_start     (gboolean debug);
 void     nm_logging_shutdown  (void);
 
 #endif /* NM_LOGGING_H */

src/main.c

@@ -305,6 +305,7 @@ main (int argc, char *argv[])
 {
 	GOptionContext *opt_ctx = NULL;
 	gboolean become_daemon = FALSE;
+	gboolean debug = FALSE;
 	gboolean g_fatal_warnings = FALSE;
 	gs_free char *pidfile = NULL;
 	gs_free char *state_file = NULL;
@@ -325,6 +326,7 @@ main (int argc, char *argv[])
 	GOptionEntry options[] = {
 		{ "version", 0, 0, G_OPTION_ARG_NONE, &show_version, N_("Print NetworkManager version and exit"), NULL },
 		{ "no-daemon", 0, G_OPTION_FLAG_REVERSE, G_OPTION_ARG_NONE, &become_daemon, N_("Don't become a daemon"), NULL },
+		{ "debug", 0, 0, G_OPTION_ARG_NONE, &debug, N_("Don't become a daemon, and log to stderr"), NULL },
 		{ "g-fatal-warnings", 0, 0, G_OPTION_ARG_NONE, &g_fatal_warnings, N_("Make all warnings fatal"), NULL },
 		{ "pid-file", 0, 0, G_OPTION_ARG_FILENAME, &pidfile, N_("Specify the location of a PID file"), N_("filename") },
 		{ "state-file", 0, 0, G_OPTION_ARG_FILENAME, &state_file, N_("State file location"), N_("/path/to/state.file") },
@@ -426,7 +428,7 @@ main (int argc, char *argv[])
 	}
 	g_clear_error (&error);
 
-	if (become_daemon) {
+	if (become_daemon && !debug) {
 		if (daemon (0, 0) < 0) {
 			int saved_errno;
 
@@ -467,7 +469,7 @@ main (int argc, char *argv[])
 	 */
 	dbus_glib_global_set_disable_legacy_property_access ();
 
-	nm_logging_start (become_daemon);
+	nm_logging_start (debug);
 
 	nm_log_info (LOGD_CORE, "NetworkManager (version " NM_DIST_VERSION ") is starting...");
 	success = FALSE;