Add support multiple nameservers in /etc/resolv.conf

Nameservers are appended to a local entry list.  The MAXNS most recently
appended nameservers are written to /etc/resolv.conf in reverse order
(the most recently appended entry becomes the primary nameserver).

diff --git a/src/resolver.c b/src/resolver.c
index df0d3c1..4a9db26 100644 (file)
--- a/src/resolver.c
+++ b/src/resolver.c
@@ -29,6 +29,7 @@
 #include <unistd.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <resolv.h>
 
 #include "connman.h"
 
@@ -333,17 +334,56 @@ int __connman_resolver_selftest(void)
        return 0;
 }
 
-static int resolvfile_append(const char *interface, const char *domain,
-                                                       const char *server)
+struct resolvfile_entry {
+       char *interface;
+       char *domain;
+       char *server;
+};
+
+static GList *resolvfile_list = NULL;
+
+static void resolvfile_remove_entries(GList *entries)
 {
-       char *cmd;
-       int fd, len, err;
-       mode_t old_umask;
+       GList *list;
 
-       DBG("interface %s server %s", interface, server);
+       for (list = entries; list; list = list->next) {
+               struct resolvfile_entry *entry = list->data;
 
-       if (interface == NULL)
-               return -ENOENT;
+               resolvfile_list = g_list_remove(
+                                       resolvfile_list, entry);
+
+               g_free(entry->server);
+               g_free(entry->domain);
+               g_free(entry->interface);
+               g_free(entry);
+       }
+
+       g_list_free(entries);
+}
+
+static int resolvfile_export(void)
+{
+       GList *list;
+       GString *content;
+       int fd, err;
+       unsigned int count;
+       mode_t old_umask;
+
+       content = g_string_new("# Generated by Connection Manager\n"
+                                               "options edns0\n");
+
+       /* Nameservers are added in reverse so that the most recently appended
+        * entry is the primary nameserver.  No more than MAXNS nameservers are
+        * used.
+        */
+       for (count = 0, list = g_list_last(resolvfile_list);
+                                               list && (count < MAXNS);
+                                               list = g_list_previous(list)) {
+               struct resolvfile_entry *entry = list->data;
+               g_string_append_printf(content, "nameserver %s\n",
+                                                               entry->server);
+               count++;
+       }
 
        old_umask = umask(022);
 
@@ -361,31 +401,68 @@ static int resolvfile_append(const char *interface, const char *domain,
 
        err = 0;
 
-       cmd = g_strdup_printf("# Generated by Connection Manager\n"
-                                               "options edns0\n"
-                                               "nameserver %s\n", server);
-
-       len = write(fd, cmd, strlen(cmd));
-       if (len < 0)
+       if (write(fd, content->str, content->len) < 0)
                err = -errno;
 
-       g_free(cmd);
-
 failed:
        close(fd);
 
 done:
+       g_string_free(content, TRUE);
        umask(old_umask);
 
        return err;
 }
 
+static int resolvfile_append(const char *interface, const char *domain,
+                                                       const char *server)
+{
+       struct resolvfile_entry *entry;
+
+       DBG("interface %s server %s", interface, server);
+
+       if (interface == NULL)
+               return -ENOENT;
+
+       entry = g_try_new0(struct resolvfile_entry, 1);
+       if (entry == NULL)
+               return -ENOMEM;
+
+       entry->interface = g_strdup(interface);
+       entry->domain = g_strdup(domain);
+       entry->server = g_strdup(server);
+
+       resolvfile_list = g_list_append(resolvfile_list, entry);
+
+       return resolvfile_export();
+}
+
 static int resolvfile_remove(const char *interface, const char *domain,
                                                        const char *server)
 {
+       GList *list, *matches = NULL;
+
        DBG("interface %s server %s", interface, server);
 
-       return 0;
+       for (list = resolvfile_list; list; list = g_list_next(list)) {
+               struct resolvfile_entry *entry = list->data;
+
+               if (interface != NULL &&
+                               g_strcmp0(entry->interface, interface) != 0)
+                       continue;
+
+               if (domain != NULL && g_strcmp0(entry->domain, domain) != 0)
+                       continue;
+
+               if (g_strcmp0(entry->server, server) != 0)
+                       continue;
+
+               matches = g_list_append(matches, entry);
+       }
+
+       resolvfile_remove_entries(matches);
+
+       return resolvfile_export();
 }
 
 static struct connman_resolver resolvfile_resolver = {