rest: extract og_get_boot_modes from og_cmd_get_modes()

og_cmd_get_modes() now uses a helper function that returns a list of all boot
modes, this is for a new API REST validate that boot mode is set to something
that exists in a follow up patch.

src/rest.c

@@ -1012,15 +1012,68 @@ static int og_cmd_reboot(json_t *element, struct og_msg_params *params)
 #define OG_TFTP_TMPL_PATH_UEFI "/opt/opengnsys/tftpboot/grub/templates"
 #define OG_TFTP_TMPL_PATH "/opt/opengnsys/tftpboot/menu.lst/templates"
 
+struct og_boot_mode {
+	struct list_head	list;
+	char			name[FILENAME_MAX];
+};
+
+static void og_boot_mode_free(struct list_head *boot_mode_list)
+{
+	struct og_boot_mode *mode, *tmp;
+
+	list_for_each_entry_safe(mode, tmp, boot_mode_list, list) {
+		list_del(&mode->list);
+		free(mode);
+	}
+}
+
+static int og_get_boot_modes(struct list_head *boot_mode_list)
+{
+	struct og_boot_mode *mode;
+	struct dirent *dent;
+	DIR *d;
+
+	d = opendir(OG_TFTP_TMPL_PATH);
+	if (!d) {
+		syslog(LOG_ERR, "Cannot open directory %s (%s:%d)\n",
+		       OG_TFTP_TMPL_PATH, __func__, __LINE__);
+		return -1;
+	}
+
+	dent = readdir(d);
+	while (dent) {
+		if (dent->d_type != DT_REG) {
+			dent = readdir(d);
+			continue;
+		}
+
+		mode = calloc(1, sizeof(struct og_boot_mode));
+		if (!mode) {
+			closedir(d);
+			og_boot_mode_free(boot_mode_list);
+			return -1;
+		}
+
+		snprintf(mode->name, FILENAME_MAX, "%s", dent->d_name);
+		list_add_tail(&mode->list, boot_mode_list);
+
+		dent = readdir(d);
+	}
+	closedir(d);
+
+	return 0;
+}
+
 static int og_cmd_get_modes(json_t *element, struct og_msg_params *params,
 			    char *buffer_reply)
 {
 	struct og_buffer og_buffer = {
 		.data = buffer_reply
 	};
+	struct og_boot_mode *mode;
+	LIST_HEAD(boot_mode_list);
 	json_t *root, *modes;
-	struct dirent *dent;
+	int ret;
-	DIR *d = NULL;
 
 	root = json_object();
 	if (!root)
@@ -1032,35 +1085,22 @@ static int og_cmd_get_modes(json_t *element, struct og_msg_params *params,
 		return -1;
 	}
 
-	d = opendir(OG_TFTP_TMPL_PATH);
+	if (og_get_boot_modes(&boot_mode_list) < 0) {
-	if (!d) {
 		json_decref(modes);
 		json_decref(root);
-		syslog(LOG_ERR, "Cannot open directory %s\n",
-		       OG_TFTP_TMPL_PATH);
 		return -1;
 	}
 
-	dent = readdir(d);
+	list_for_each_entry(mode, &boot_mode_list, list)
-	while (dent) {
+		json_array_append_new(modes, json_string(mode->name));
-		if (dent->d_type != DT_REG) {
+
-			dent = readdir(d);
+	og_boot_mode_free(&boot_mode_list);
-			continue;
-		}
-		json_array_append_new(modes, json_string(dent->d_name));
-		dent = readdir(d);
-	}
 	json_object_set_new(root, "modes", modes);
 
-	if (json_dump_callback(root, og_json_dump_clients, &og_buffer, 0)) {
+	ret = json_dump_callback(root, og_json_dump_clients, &og_buffer, 0);
 	json_decref(root);
-		return -1;
-	}
 
-	json_decref(root);
+	return ret;
-	closedir(d);
-
-	return 0;
 }
 
 static int og_change_db_mode(struct og_dbi *dbi, const char *mac,