chiark / gitweb /
logind: ignore failing close() on session-devices
authorDavid Herrmann <dh.herrmann@gmail.com>
Thu, 28 Nov 2013 13:51:40 +0000 (14:51 +0100)
committerDavid Herrmann <dh.herrmann@gmail.com>
Thu, 28 Nov 2013 14:16:49 +0000 (15:16 +0100)
Unfortunately, close() on a revoked/removed character-device fails with
ENODEV. I tried tracking this down in the kernel, but couldn't figure out
were exactly it comes from. However, can be easily reproduced with:
  fd = open("/dev/input/event0", O_RDWR);
  ioctl(fd, EVIOCREVOKE, 0);
  r = close(fd);
A second close on @fd would return EBADF so the close is actually valid.

We simply ignore close() errors for all session-devices as their access
may be revoked asynchronously, or the device might get unplugged.
We use close_nointr() in case anyone ever looks at the return value (or
anyone runs "grep 'close(' -r src/" to find broken close() calls).

Fixes:
  systemd-logind[31992]: Assertion 'close_nointr(fd) == 0' failed at src/shared/util.c:185, function close_nointr_nofail(). Aborting.

src/login/logind-session-device.c

index b2ef8cc..592bcf2 100644 (file)
@@ -162,7 +162,7 @@ static int session_device_open(SessionDevice *sd, bool active) {
                          * state. */
                         r = sd_drmsetmaster(fd);
                         if (r < 0) {
-                                close(fd);
+                                close_nointr(fd);
                                 return r;
                         }
                 } else {
@@ -209,7 +209,7 @@ static int session_device_start(SessionDevice *sd) {
                 r = session_device_open(sd, true);
                 if (r < 0)
                         return r;
-                close_nointr_nofail(sd->fd);
+                close_nointr(sd->fd);
                 sd->fd = r;
                 break;
         case DEVICE_TYPE_UNKNOWN:
@@ -407,7 +407,7 @@ void session_device_free(SessionDevice *sd) {
 
         session_device_stop(sd);
         session_device_notify(sd, SESSION_DEVICE_RELEASE);
-        close_nointr_nofail(sd->fd);
+        close_nointr(sd->fd);
 
         LIST_REMOVE(sd_by_device, sd->device->session_devices, sd);