From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-335357-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 15374 invoked by alias); 2 Nov 2010 11:17:37 -0000
Received: (qmail 15350 invoked by uid 22791); 2 Nov 2010 11:17:35 -0000
X-SWARE-Spam-Status: No, hits=-2.6 required=5.0	tests=ALL_TRUSTED,AWL,BAYES_00
X-Spam-Check-By: sourceware.org
Received: from localhost (HELO gcc.gnu.org) (127.0.0.1)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 02 Nov 2010 11:17:31 +0000
From: "jb at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libfortran/46267] New: strerror() is not necessarily thread-safe
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: libfortran
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jb at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
Message-ID: <bug-46267-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Date: Tue, 02 Nov 2010 11:17:00 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2010-11/txt/msg00090.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46267

           Summary: strerror() is not necessarily thread-safe
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jb@gcc.gnu.org


In libgfortran/io/unix.c (get_oserror) strerror() is called. However, according
to POSIX

http://www.opengroup.org/onlinepubs/9699919799/functions/strerror.html

"The strerror() function need not be thread-safe."

Possible solutions

- On some targets such as Solaris 9 strerror() is thread-safe.

- On Windows there is apparently a thread-safe strerror_s() function.

- POSIX has the thread-safe strerror_r() function. Unfortunately it suffers
from a few issues.
   1) The interface is a bit cumbersome, the caller must allocate a buffer for
the message and pass it in
   2) glibc has also another strerror_r() function with an incompatible
interface. Thus one needs to do some macro trickery to use the POSIX version,
or then use the GNU version on glibc targets.
  In short, it's a trainwreck. See e.g.
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6223913  and
https://www.securecoding.cert.org/confluence/display/seccode/CON33-C.+Avoid+race+conditions+when+using+library+functions

- POSIX 2008 has the strerror_l() function which is thread-safe and has a
similar interface as strerror(). Using this, if available, is perhaps the
simplest solution and should at least fix the issue on platforms which have
this function.