[PATCH] ifupdown: Use recursive_action for "source-directory"

[Brandon Maier]

There is an existing function for recursing through directories. So use
that instead. source-directory only recurses through a single directory,
so we set a maximum depth of 1.

ifupdown only selects files that match the regex '^[a-zA-Z0-9_-]+$'[1].
Comply so that we don't include invalid files.

[1] https://manpages.debian.org/stretch/ifupdown/interfaces.5.en.html#INCLUDING_OTHER_FILES

Signed-off-by: Brandon Maier <brandon.maier at rockwellcollins.com>
---
 networking/ifupdown.c | 47 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 35 insertions(+), 12 deletions(-)

diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index 41cc86df7..ef6b185fc 100644
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -159,6 +159,8 @@
 /* Forward declaration */
 struct interface_defn_t;
 
+static struct interfaces_file_t *read_interfaces(const char *filename, struct interfaces_file_t *defn);
+
 typedef int execfn(char *command);
 
 struct method_t {
@@ -857,6 +859,31 @@ static const struct method_t *get_method(const struct address_family_t *af, char
 	return NULL;
 }
 
+static int FAST_FUNC read_interfaces_action(const char *fileName,
+		struct stat *statbuf UNUSED_PARAM, void* userData, int depth)
+{
+	const char *p;
+
+	if (depth == 0)
+		return SKIP;
+
+	for (p = bb_basename(fileName); *p; p++)
+		if (!(isalnum(*p) || *p == '_' || *p == '-'))
+			return SKIP;
+
+	read_interfaces(fileName, userData);
+
+	return TRUE;
+}
+
+static int FAST_FUNC max_depth_one(const char *fileName UNUSED_PARAM,
+		struct stat *statbuf UNUSED_PARAM, void* userData UNUSED_PARAM, int depth)
+{
+	if (depth > 0)
+		return SKIP;
+	return TRUE;
+}
+
 static struct interfaces_file_t *read_interfaces(const char *filename, struct interfaces_file_t *defn)
 {
 	/* Let's try to be compatible.
@@ -1019,20 +1046,16 @@ static struct interfaces_file_t *read_interfaces(const char *filename, struct in
 			read_interfaces(next_word(&rest_of_line), defn);
 		} else if (is_prefixed_with(first_word, "source-dir")) {
 			const char *dirpath;
-			DIR *dir;
-			struct dirent *entry;
 
 			dirpath = next_word(&rest_of_line);
-			dir = xopendir(dirpath);
-			while ((entry = readdir(dir)) != NULL) {
-				char *path;
-				if (entry->d_name[0] == '.')
-					continue;
-				path = concat_path_file(dirpath, entry->d_name);
-				read_interfaces(path, defn);
-				free(path);
-			}
-			closedir(dir);
+			debug_noise("%s %s\n", first_word, dirpath);
+			recursive_action(dirpath,
+					ACTION_RECURSE|ACTION_FOLLOWLINKS|ACTION_QUIET,
+					read_interfaces_action, /* file action */
+					max_depth_one, /* dir action */
+					defn, /* user data */
+					0 /* depth */
+				);
 		} else {
 			switch (currently_processing) {
 			case IFACE:
-- 
2.19.0