networkd: add basic dbus API

[elogind.git] / src / core / loopback-setup.c

diff --git a/src/core/loopback-setup.c b/src/core/loopback-setup.c
index 6ac1fffd75f9c74c2ec38fd5f1526f1530b64e30..67ce160c1982f9cb7084cc3e9b7898cc6d4c7c64 100644 (file)
--- a/src/core/loopback-setup.c
+++ b/src/core/loopback-setup.c
@@ -27,15 +27,13 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+#include "sd-rtnl.h"
 #include "util.h"
 #include "macro.h"
-#include "loopback-setup.h"
 #include "socket-util.h"
-#include "sd-rtnl.h"
 #include "rtnl-util.h"
-
-/* this is hardcoded in the kernel, so don't look it up */
-#define LOOPBACK_IFINDEX 1
+#include "missing.h"
+#include "loopback-setup.h"
 
 static int start_loopback(sd_rtnl *rtnl) {
         _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
@@ -56,30 +54,24 @@ static int start_loopback(sd_rtnl *rtnl) {
         return 0;
 }
 
-static int check_loopback(void) {
+static bool check_loopback(sd_rtnl *rtnl) {
+        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL, *reply = NULL;
+        unsigned flags;
         int r;
-        _cleanup_close_ int fd = -1;
-        union {
-                struct sockaddr sa;
-                struct sockaddr_in in;
-        } sa = {
-                .in.sin_family = AF_INET,
-                .in.sin_addr.s_addr = INADDR_LOOPBACK,
-        };
-
-        /* If we failed to set up the loop back device, check whether
-         * it might already be set up */
-
-        fd = socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
-        if (fd < 0)
-                return -errno;
-
-        if (bind(fd, &sa.sa, sizeof(sa.in)) >= 0)
-                r = 1;
-        else
-                r = errno == EADDRNOTAVAIL ? 0 : -errno;
-
-        return r;
+
+        r = sd_rtnl_message_new_link(rtnl, &req, RTM_GETLINK, LOOPBACK_IFINDEX);
+        if (r < 0)
+                return false;
+
+        r = sd_rtnl_call(rtnl, req, 0, &reply);
+        if (r < 0)
+                return false;
+
+        r = sd_rtnl_message_link_get_flags(reply, &flags);
+        if (r < 0)
+                return false;
+
+        return flags & IFF_UP;
 }
 
 int loopback_setup(void) {
@@ -91,18 +83,17 @@ int loopback_setup(void) {
                 return r;
 
         r = start_loopback(rtnl);
-        if (r == -EPERM) {
-                if (check_loopback() < 0) {
-                        log_warning("Failed to configure loopback device: %s",
-                                    strerror(EPERM));
-                        return -EPERM;
-                }
-        } else if (r < 0) {
-                log_warning("Failed to configure loopback device: %s",
-                            strerror(-r));
-                return r;
-        }
+        if (r < 0) {
 
+                /* If we lack the permissions to configure the
+                 * loopback device, but we find it to be already
+                 * configured, let's exit cleanly, in order to
+                 * supported unprivileged containers. */
+                if (r == -EPERM && check_loopback(rtnl))
+                        return 0;
+
+                return log_warning_errno(r, "Failed to configure loopback device: %m");
+        }
 
         return 0;
 }