ifupdown: support "source" stanza in /etc/network/interfaces

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 13 insertions, 6 deletions

diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index 818048284..0f0857cb4 100644
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -743,7 +743,7 @@ static const struct method_t *get_method(const struct address_family_t *af, char
         return NULL;
 }
 
-static struct interfaces_file_t *read_interfaces(const char *filename)
+static struct interfaces_file_t *read_interfaces(const char *filename, struct interfaces_file_t *defn)
 {
         /* Let's try to be compatible.
          *
@@ -758,19 +758,25 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
          * be ignored. Blank lines are ignored. Lines may be indented freely.
          * A "\" character at the very end of the line indicates the next line
          * should be treated as a continuation of the current one.
+         *
+         * Lines  beginning with "source" are used to include stanzas from
+         * other files, so configuration can be split into many files.
+         * The word "source" is followed by the path of file to be sourced.
          */
 #if ENABLE_FEATURE_IFUPDOWN_MAPPING
         struct mapping_defn_t *currmap = NULL;
 #endif
         struct interface_defn_t *currif = NULL;
-        struct interfaces_file_t *defn;
         FILE *f;
         char *buf;
         char *first_word;
         char *rest_of_line;
         enum { NONE, IFACE, MAPPING } currently_processing = NONE;
 
-        defn = xzalloc(sizeof(*defn));
+        if (!defn)
+                defn = xzalloc(sizeof(*defn));
+
+        debug_noise("reading %s file:\n", filename);
         f = xfopen_for_read(filename);
 
         while ((buf = xmalloc_fgetline(f)) != NULL) {
@@ -881,6 +887,8 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
                                 debug_noise("\nauto %s\n", first_word);
                         }
                         currently_processing = NONE;
+                } else if (strcmp(first_word, "source") == 0) {
+                        read_interfaces(next_word(&rest_of_line), defn);
                 } else {
                         switch (currently_processing) {
                         case IFACE:
@@ -934,6 +942,7 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
                 bb_error_msg_and_die("%s: I/O error", filename);
         }
         fclose(f);
+        debug_noise("\ndone reading %s\n\n", filename);
 
         return defn;
 }
@@ -1199,9 +1208,7 @@ int ifupdown_main(int argc UNUSED_PARAM, char **argv)
                 if (!DO_ALL) bb_show_usage();
         }
 
-        debug_noise("reading %s file:\n", interfaces);
-        defn = read_interfaces(interfaces);
-        debug_noise("\ndone reading %s\n\n", interfaces);
+        defn = read_interfaces(interfaces, NULL);
 
         /* Create a list of interfaces to work on */
         if (DO_ALL) {