trans/fakeroot: shutdown the translator if the last client is gone

Previously, fakeroot would not exit if a process outlived the original
process started by settrans.  This caused bugs like this:

% fakeroot-hurd /bin/sh -c 'sleep 1&' 2>&1 | tee
<hangs>

Fix this by exiting if the last client of fakeroot goes away.

If noone has a right to any control or protid port, noone can ever
reacquire any such right. So it is safe to shutdown the fakeroot
translator in that case.

* trans/fakeroot.c (fakeroot_netfs_release_protid): Shutdown the
translator if the last protid object is destroyed and no control port
is around either.

1 files changed, 19 insertions, 1 deletions

diff --git a/trans/fakeroot.c b/trans/fakeroot.c
index 203f2c1b..0e0b618a 100644
--- a/trans/fakeroot.c
+++ b/trans/fakeroot.c
@@ -1,5 +1,5 @@
 /* fakeroot -- a translator for faking actions that aren't really permitted
-   Copyright (C) 2002, 2003, 2008 Free Software Foundation, Inc.
+   Copyright (C) 2002, 2003, 2008, 2013 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
@@ -184,6 +184,24 @@ fakeroot_netfs_release_protid (void *cookie)
  out:
   pthread_mutex_unlock (&np->lock);
   netfs_release_protid (cookie);
+
+  int cports = ports_count_class (netfs_control_class);
+  int nports = ports_count_class (netfs_protid_class);
+  ports_enable_class (netfs_control_class);
+  ports_enable_class (netfs_protid_class);
+  if (cports == 0 && nports == 0)
+    {
+      /* The last client is gone.  Our job is done.  */
+      error_t err = netfs_shutdown (0);
+      if (! err)
+        exit (EXIT_SUCCESS);
+
+      /* If netfs_shutdown returns EBUSY, we lost a race against
+         fsys_goaway.  Hence we ignore this error.  */
+      if (err != EBUSY)
+        error (1, err, "netfs_shutdown");
+    }
+
   pthread_mutex_unlock (&idport_ihash_lock);
 }