Added daemon run mode

Author: mobrembski

src/config.c

@@ -83,6 +83,7 @@ const struct vpn_config invalid_cfg = {
 	.user_agent = NULL,
 	.hostcheck = NULL,
 	.check_virtual_desktop = NULL,
+	.daemonize = 0
 };
 
 /*
@@ -449,6 +450,15 @@ int load_config(struct vpn_config *cfg, const char *filename)
 		} else if (strcmp(key, "check-virtual-desktop") == 0) {
 			free(cfg->check_virtual_desktop);
 			cfg->check_virtual_desktop = strdup(val);
+		} else if (strcmp(key, "daemonize") == 0) {
+			int daemonize = strtob(val);
+
+			if (daemonize < 0) {
+				log_warn("Bad daemonize in config file: \"%s\".\n",
+				         val);
+				continue;
+			}
+			cfg->daemonize = daemonize;
 		} else {
 			log_warn("Bad key in config file: \"%s\".\n", key);
 			goto err_free;
@@ -600,4 +610,6 @@ void merge_config(struct vpn_config *dst, struct vpn_config *src)
 		dst->hostcheck = src->hostcheck;
 	if (src->check_virtual_desktop != invalid_cfg.check_virtual_desktop)
 		dst->check_virtual_desktop = src->check_virtual_desktop;
+	if (src->daemonize != invalid_cfg.daemonize)
+		dst->daemonize = src->daemonize;
 }

src/main.c

@@ -144,7 +144,8 @@ PPPD_USAGE \
 "                                certificate will be matched against this value.\n" \
 "                                <digest> is the X509 certificate's sha256 sum.\n" \
 "                                This option can be used multiple times to trust\n" \
-"                                several certificates.\n"
+"                                several certificates.\n" \
+"  --daemonize                   Run in daemon mode.\n"
 
 #define help_options_part2 \
 "  --insecure-ssl                Do not disable insecure SSL protocols/ciphers.\n" \
@@ -183,13 +184,13 @@ PPPD_USAGE \
 "      trusted-cert = certificatedigest4daa8c5fe6c...\n" \
 "      trusted-cert = othercertificatedigest6631bf...\n" \
 "  For a full-featured config see man openfortivpn(1).\n"
-
 int main(int argc, char **argv)
 {
 	int ret = EXIT_FAILURE;
 	const char *config_file = SYSCONFDIR "/openfortivpn/config";
 	const char *host;
 	char *port_str;
+	pid_t process_id = 0;
 
 	struct vpn_config cfg = {
 		.gateway_host = {'\0'},
@@ -208,6 +209,7 @@ int main(int argc, char **argv)
 		.use_syslog = 0,
 		.half_internet_routes = 0,
 		.persistent = 0,
+		.daemonize = 0,
 #if HAVE_RESOLVCONF
 		.use_resolvconf = USE_RESOLVCONF,
 #endif
@@ -267,6 +269,7 @@ int main(int argc, char **argv)
 		{"cipher-list",     required_argument, NULL, 0},
 		{"min-tls",         required_argument, NULL, 0},
 		{"seclevel-1",      no_argument, &cli_cfg.seclevel_1, 1},
+		{"daemonize",       no_argument, &cli_cfg.daemonize, 1},
 #if HAVE_USR_SBIN_PPPD
 		{"pppd-use-peerdns", required_argument, NULL, 0},
 		{"pppd-no-peerdns", no_argument, &cli_cfg.pppd_use_peerdns, 0},
@@ -563,6 +566,24 @@ int main(int argc, char **argv)
 	}
 	// Then apply CLI config
 	merge_config(&cfg, &cli_cfg);
+	if (cfg.daemonize) {
+		if (cfg.use_syslog == 0) {
+			log_info("Sorry, only syslog is available when running in Daemon mode");
+			cfg.use_syslog = 1;
+		}
+		process_id = fork();
+		// Indication of fork() failure
+		if (process_id < 0) {
+			printf("Forking failure! Cannot start daemon!\n");
+			exit(1);
+		}
+		// PARENT PROCESS. Need to kill it.
+		if (process_id > 0) {
+			printf("Started as daemon with PID: %u\n", process_id);
+			/* Killing parent process */
+			exit(0);
+		}
+	}
 	set_syslog(cfg.use_syslog);
 
 	// Read host and port from the command line