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authorSamuel Thibault <samuel.thibault@ens-lyon.org>2015-03-06 11:32:24 +0100
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2015-03-06 11:32:24 +0100
commit1cdf2ea1fa44bae7d400b602399e30d490173bf3 (patch)
treea5ab1f44b094f14c4bfdbfb0d6f6837de4bcbd13 /sysdeps/pthread
parent1597b7447a81f372068b68a7830ac83aa3b4527f (diff)
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Fix aio_error thread-safety.
* sysdeps/pthread/aio_error.c: New file * sysdeps/pthread/aio_misc.c: Remove optimistic comment about synchronization.
Diffstat (limited to 'sysdeps/pthread')
-rw-r--r--sysdeps/pthread/aio_error.c49
-rw-r--r--sysdeps/pthread/aio_misc.c8
2 files changed, 49 insertions, 8 deletions
diff --git a/sysdeps/pthread/aio_error.c b/sysdeps/pthread/aio_error.c
new file mode 100644
index 0000000..ebe1378
--- /dev/null
+++ b/sysdeps/pthread/aio_error.c
@@ -0,0 +1,49 @@
+/* Return error status of asynchronous I/O request.
+ Copyright (C) 1997-2015 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+
+/* We use an UGLY hack to prevent gcc from finding us cheating. The
+ implementation of aio_error and aio_error64 are identical and so
+ we want to avoid code duplication by using aliases. But gcc sees
+ the different parameter lists and prints a warning. We define here
+ a function so that aio_error64 has no prototype. */
+#define aio_error64 XXX
+#include <aio.h>
+/* And undo the hack. */
+#undef aio_error64
+
+#include <aio_misc.h>
+
+
+int
+aio_error (aiocbp)
+ const struct aiocb *aiocbp;
+{
+ int ret;
+
+ /* Acquire the mutex to make sure all operations for this request are
+ complete. */
+ pthread_mutex_lock(&__aio_requests_mutex);
+ ret = aiocbp->__error_code;
+ pthread_mutex_unlock(&__aio_requests_mutex);
+
+ return ret;
+}
+
+weak_alias (aio_error, aio_error64)
diff --git a/sysdeps/pthread/aio_misc.c b/sysdeps/pthread/aio_misc.c
index 5d2b81e..83a6cb9 100644
--- a/sysdeps/pthread/aio_misc.c
+++ b/sysdeps/pthread/aio_misc.c
@@ -593,14 +593,6 @@ handle_fildes_io (void *arg)
/* Get the mutex. */
pthread_mutex_lock (&__aio_requests_mutex);
- /* In theory we would need here a write memory barrier since the
- callers test using aio_error() whether the request finished
- and once this value != EINPROGRESS the field __return_value
- must be committed to memory.
-
- But since the pthread_mutex_lock call involves write memory
- barriers as well it is not necessary. */
-
if (aiocbp->aiocb.__return_value == -1)
aiocbp->aiocb.__error_code = errno;
else