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

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

diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index 818048284a45cae1de62a3e70fa6f51c1f4c844b..0f0857cb41160b3eec39c696dcb9185f440f078c 100644 (file)
--- 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) {