From 520ef2ed66d47bb81a55829a88dda81f62dc95e5 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Fri, 20 Jun 2014 13:54:28 +0200
Subject: libdiskfs: fix reference counting of peropen objects

Previously, peropen objects were created with a reference count of
zero.  Therefore, if diskfs_create_protid fails, passing such an
object to diskfs_release_peropen would lead to a reference count
underflow.

* libdiskfs/peropen-make.c (diskfs_peropen_make): Initialize reference
count to one.
* libdiskfs/protid-make.c (diskfs_start_protid): And consume this
reference on success.  Update comment.
(diskfs_create_protid): Update comment.
* libdiskfs/diskfs.h: Update comments.
* libdiskfs/io-duplicate.c (diskfs_S_io_duplicate): Adjust reference
counting accordingly.
* libdiskfs/io-reauthenticate.c (diskfs_S_io_reauthenticate): Likewise.
* libdiskfs/io-restrict-auth.c (diskfs_S_io_restrict_auth): Likewise.
* doc/hurd.texi (Diskfs Internals): Update accordingly.
---
 libdiskfs/io-restrict-auth.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'libdiskfs/io-restrict-auth.c')

diff --git a/libdiskfs/io-restrict-auth.c b/libdiskfs/io-restrict-auth.c
index 011aa19e..80c0b208 100644
--- a/libdiskfs/io-restrict-auth.c
+++ b/libdiskfs/io-restrict-auth.c
@@ -41,6 +41,7 @@ diskfs_S_io_restrict_auth (struct protid *cred,
     return err;
 
   pthread_mutex_lock (&cred->po->np->lock);
+  refcount_ref (&cred->po->refcnt);
   err = diskfs_create_protid (cred->po, user, &newpi);
   if (! err)
     {
@@ -48,6 +49,8 @@ diskfs_S_io_restrict_auth (struct protid *cred,
       *newportpoly = MACH_MSG_TYPE_MAKE_SEND;
       ports_port_deref (newpi);
     }
+  else
+    refcount_deref (&cred->po->refcnt);
   pthread_mutex_unlock (&cred->po->np->lock);
 
   iohelp_free_iouser (user);
-- 
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