Clvmd restart cleanup

Patch fixes Clang warnings about possible access via lv_name NULL pointer.

Replaces allocation of memory (strdup) with just pointer assignment
(since execve is being called anyway).

Checks for  !*lv_name only when lv_name is defined.
(and as I'm not quite sure what state this really is - putting a FIXME
around - as this rather looks suspicios ??).

Add debug print of passed clvmd args.

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.89 - 
 ==================================
+  Cleanup restart clvmd code (no memory allocation, debug print passed args).
   Add all exclusive locks to clvmd restart option args.
   Always send the whole clvmd packet header in refresh commands.
   Add missing error checks for some system calls in cmirrord.

daemons/clvmd/clvmd-command.c

@@ -361,39 +361,38 @@ void cmd_client_cleanup(struct local_client *client)
 
 static int restart_clvmd(void)
 {
-	char **argv = NULL;
+	const char **argv;
-	char *debug_arg = NULL, *lv_name;
+	char *lv_name;
-	int i, argc = 0, max_locks = 0;
+	int argc = 0, max_locks = 0;
 	struct dm_hash_node *hn = NULL;
+	char debug_arg[16];
 
 	DEBUGLOG("clvmd restart requested\n");
 
 	/* Count exclusively-open LVs */
 	do {
 		hn = get_next_excl_lock(hn, &lv_name);
-		if (lv_name)
+		if (lv_name) {
 			max_locks++;
-	} while (hn && *lv_name);
+			if (!*lv_name)
+				break; /* FIXME: Is this error ? */
+		}
+	} while (hn);
 
 	/* clvmd + locks (-E uuid) + debug (-d X) + NULL */
-	argv = malloc((max_locks * 2 + 4) * sizeof(*argv));
+	if (!(argv = malloc((max_locks * 2 + 4) * sizeof(*argv))))
-	if (!argv)
 		goto_out;
 
 	/*
 	 * Build the command-line
 	 */
-	argv[argc++] = strdup("clvmd");
+	argv[argc++] = "clvmd";
-	if (!argv[0])
-		goto_out;
 
 	/* Propogate debug options */
 	if (clvmd_get_debug()) {
-		if (!(debug_arg = malloc(16)) ||
+		if (dm_snprintf(debug_arg, sizeof(debug_arg), "-d%u", clvmd_get_debug()) < 0)
-		    dm_snprintf(debug_arg, 16, "-d%u", clvmd_get_debug()) < 0)
 			goto_out;
 		argv[argc++] = debug_arg;
-		debug_arg = NULL;
 	}
 
 	/*
@@ -406,30 +405,26 @@ static int restart_clvmd(void)
 	do {
 		hn = get_next_excl_lock(hn, &lv_name);
 		if (lv_name) {
-			argv[argc] = strdup("-E");
+			if (!*lv_name)
-			if (!argv[argc++])
+				break; /* FIXME: Is this error ? */
-				goto_out;
+			argv[argc++] = "-E";
-			argv[argc] = strdup(lv_name);
+			argv[argc++] = lv_name;
-			if (!argv[argc++])
-				goto_out;
-
 			DEBUGLOG("excl lock: %s\n", lv_name);
 		}
-	} while (hn && *lv_name);
+	} while (hn);
-	argv[argc++] = NULL;
+	argv[argc] = NULL;
 
 	/* Exec new clvmd */
 	DEBUGLOG("--- Restarting %s ---\n", CLVMD_PATH);
+	for (argc = 1; argv[argc]; argc++) DEBUGLOG("--- %d: %s\n", argc, argv[argc]);
+
 	/* NOTE: This will fail when downgrading! */
-	execve(CLVMD_PATH, argv, NULL);
+	execve(CLVMD_PATH, (char **)argv, NULL);
 out:
 	/* We failed */
 	DEBUGLOG("Restart of clvmd failed.\n");
 
-	for (i = 0; i < argc && argv[i]; i++)
-		free(argv[i]);
 	free(argv);
-	free(debug_arg);
 
 	return EIO;
 }