X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fcore%2Floopback-setup.c;h=63b15c12009e345ee9343151841ca2a2dd1c8f22;hb=c43b2132f37264600cc26e07c8d85dfdd6c969f0;hp=6ac1fffd75f9c74c2ec38fd5f1526f1530b64e30;hpb=f3fc48150bb443f5b4623a819ebc2b39971a4f66;p=elogind.git

diff --git a/src/core/loopback-setup.c b/src/core/loopback-setup.c
index 6ac1fffd7..63b15c120 100644
--- a/src/core/loopback-setup.c
+++ b/src/core/loopback-setup.c
@@ -19,23 +19,13 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#include <sys/socket.h>
 #include <net/if.h>
-#include <asm/types.h>
-#include <netinet/in.h>
-#include <string.h>
 #include <stdlib.h>
-#include <unistd.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 +46,24 @@ 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 +75,17 @@ 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;
 }