service_register(): guard against loss of command args

We use strtok() quite extensively in .conf parser.  Parsing of a service
line is split in two, with the command arguments being parsed very late.

Adding a new sub-option parser, based on strtok(), risk losing command
arguments.  Thus, change to use strtok_r() so that we always know where
the arg parser is.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/service.c

@@ -1175,13 +1175,8 @@ static char *parse_name(char *cmd, char *arg)
 
 /*
  * Update the command line args in the svc struct
- *
- * strtok internal pointer must be positioned at first command line arg
- * when this function is called.
- *
- * Side effect: strtok internal pointer will be modified.
  */
-static void parse_cmdline_args(svc_t *svc, char *cmd)
+static void parse_cmdline_args(svc_t *svc, char *cmd, char **args)
 {
 	int diff = 0;
 	char sep = 0;
@@ -1196,7 +1191,7 @@ static void parse_cmdline_args(svc_t *svc, char *cmd)
 	 * Copy supplied args. Stop at MAX_NUM_SVC_ARGS-1 to allow the args
 	 * array to be zero-terminated.
 	 */
-	while ((arg = strtok(NULL, " ")) && i < (MAX_NUM_SVC_ARGS - 1)) {
+	while ((arg = strtok_r(NULL, " ", args)) && i < (MAX_NUM_SVC_ARGS - 1)) {
 		char prev[sizeof(svc->args[0])] = { 0 };
 		char ch = arg[0];
 		size_t len;
@@ -1327,7 +1322,7 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 	int restart_max = SVC_RESPAWN_MAX;
 	int restart_tmo = 0;
 	unsigned oncrash_action = SVC_ONCRASH_IGNORE;
-	char *line;
+	char *line, *args;
 	svc_t *svc;
 
 	if (!cfg) {
@@ -1357,7 +1352,7 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 		}
 	}
 
-	cmd = strtok(line, " \t");
+	cmd = strtok_r(line, " \t", &args);
 	if (!cmd) {
 	incomplete:
 		errx(1, "Incomplete service '%s', cannot register", cfg);
@@ -1430,7 +1425,7 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 			break;
 
 		/* Check if valid command follows... */
-		cmd = strtok(NULL, " ");
+		cmd = strtok_r(NULL, " ", &args);
 		if (!cmd)
 			goto incomplete;
 	}
@@ -1448,7 +1443,7 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 	if (type == SVC_TYPE_TTY) {
 		size_t i, len = 0;
 
-		if (tty_parse_args(cmd, &tty))
+		if (tty_parse_args(&tty, cmd, &args))
 			return errno;
 
 		if (tty.cmd)
@@ -1469,7 +1464,7 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 			strlcat(line, tty.args[i], len);
 		}
 
-		cmd = strtok(line, " \t");
+		cmd = strtok_r(line, " \t", &args);
 		if (!cmd)
 			return errno;
 
@@ -1559,7 +1554,7 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 		strlcpy(svc->id, id, sizeof(svc->id));
 	}
 
-	parse_cmdline_args(svc, cmd);
+	parse_cmdline_args(svc, cmd, &args);
 
 	/*
 	 * Warn if svc generates same condition (based on name:id)

src/tty.c

@@ -133,7 +133,9 @@ char *tty_atcon(void)
 
 /**
  * tty_parse_args - Parse cmdline args for a tty
- * @cmd: command or tty
+ * @tty:  service tty
+ * @cmd:  command or tty
+ * @args: args from strtok_r()
  *
  * A Finit tty line can use the internal getty implementation or an
  * external one, like the BusyBox getty for instance.  This function
@@ -151,7 +153,7 @@ char *tty_atcon(void)
  * Different getty implementations prefer the TTY device argument in
  * different order, so take care to investigate this first.
  */
-int tty_parse_args(char *cmd, struct tty *tty)
+int tty_parse_args(struct tty *tty, char *cmd, char **args)
 {
 	char  *dev = NULL;
 	int passenv = 0;
@@ -175,7 +177,7 @@ int tty_parse_args(char *cmd, struct tty *tty)
 		else
 			tty->args[tty->num++] = cmd;
 
-		cmd = strtok(NULL, " ");
+		cmd = strtok_r(NULL, " ", args);
 	} while (cmd && tty->num < NELEMS(tty->args));
 
 	/* rescue shells are always notty */

src/tty.h

@@ -48,7 +48,7 @@ char	*tty_canonicalize (char *dev);
 int	 tty_isatcon      (char *dev);
 char	*tty_atcon	  (void);
 
-int	 tty_parse_args   (char *cmdline, struct tty *tty);
+int	 tty_parse_args   (struct tty *tty, char *cmd, char **args);
 
 int	 tty_exists	  (char *dev);
 int	 tty_exec	  (svc_t *tty);