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).

1 files changed, 94 insertions, 17 deletions

diff --git a/src/resolver.c b/src/resolver.c
index df0d3c15..4a9db266 100644
--- 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 = {