lib: Add new cli to specify where to output logs on startup

When we are starting a daemon, allow the user to specify:

--log <stdout|syslog|file:file_name>

This can be used on early startup to put the log files
where the end user wants them to show up.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

lib/command.c

@@ -2429,7 +2429,8 @@ static int set_log_file(struct vty *vty, const char *fname, int loglevel)
 		XFREE(MTYPE_TMP, p);
 
 	if (!ret) {
-		vty_out(vty, "can't open logfile %s\n", fname);
+		if (vty)
+			vty_out(vty, "can't open logfile %s\n", fname);
 		return CMD_WARNING_CONFIG_FAILED;
 	}
 
@@ -2445,6 +2446,26 @@ static int set_log_file(struct vty *vty, const char *fname, int loglevel)
 	return CMD_SUCCESS;
 }
 
+void command_setup_early_logging(const char *option)
+{
+	char *token;
+
+	if (strcmp(option, "stdout") == 0) {
+		zlog_set_level(ZLOG_DEST_STDOUT, zlog_default->default_lvl);
+		return;
+	}
+
+	if (strcmp(option, "syslog") == 0) {
+		zlog_set_level(ZLOG_DEST_SYSLOG, zlog_default->default_lvl);
+		return;
+	}
+
+	token = strstr(option, ":");
+	token++;
+
+	set_log_file(NULL, token, zlog_default->default_lvl);
+}
+
 DEFUN (config_log_file,
        config_log_file_cmd,
        "log file FILENAME [<emergencies|alerts|critical|errors|warnings|notifications|informational|debugging>]",

lib/command.h

@@ -479,4 +479,5 @@ extern void
 cmd_variable_handler_register(const struct cmd_variable_handler *cvh);
 extern char *cmd_variable_comp2str(vector comps, unsigned short cols);
 
+extern void command_setup_early_logging(const char *option);
 #endif /* _ZEBRA_COMMAND_H */

lib/libfrr.c

@@ -78,6 +78,7 @@ static void opt_extend(const struct optspec *os)
 
 #define OPTION_VTYSOCK   1000
 #define OPTION_MODULEDIR 1002
+#define OPTION_LOG 1003
 
 static const struct option lo_always[] = {
 	{"help", no_argument, NULL, 'h'},
@@ -86,6 +87,7 @@ static const struct option lo_always[] = {
 	{"module", no_argument, NULL, 'M'},
 	{"vty_socket", required_argument, NULL, OPTION_VTYSOCK},
 	{"moduledir", required_argument, NULL, OPTION_MODULEDIR},
+	{"log", required_argument, NULL, OPTION_LOG},
 	{NULL}};
 static const struct optspec os_always = {
 	"hvdM:",
@@ -94,7 +96,8 @@ static const struct optspec os_always = {
 	"  -d, --daemon       Runs in daemon mode\n"
 	"  -M, --module       Load specified module\n"
 	"      --vty_socket   Override vty socket path\n"
-	"      --moduledir    Override modules directory\n",
+	"      --moduledir    Override modules directory\n"
+	"      --log          Set Logging to stdout, syslog, or file:<name>\n",
 	lo_always};
 
 
@@ -444,6 +447,9 @@ static int frr_opt(int opt)
 			return 1;
 		di->privs->group = optarg;
 		break;
+	case OPTION_LOG:
+		di->early_logging = optarg;
+		break;
 	default:
 		return 1;
 	}
@@ -543,6 +549,9 @@ struct thread_master *frr_init(void)
 
 	openzlog(di->progname, di->logname, di->instance,
 		 LOG_CONS | LOG_NDELAY | LOG_PID, LOG_DAEMON);
+
+	if (di->early_logging)
+		command_setup_early_logging(di->early_logging);
 #if defined(HAVE_CUMULUS)
 	zlog_set_level(ZLOG_DEST_SYSLOG, zlog_default->default_lvl);
 #endif

lib/libfrr.h

@@ -58,6 +58,7 @@ struct frr_daemon_info {
 	const char *vty_path;
 	const char *module_path;
 	const char *pathspace;
+	const char *early_logging;
 
 	const char *proghelp;
 	void (*printhelp)(FILE *target);