From b6d1dc09b620742b1877935f9f21a90a13ca5ee1 Mon Sep 17 00:00:00 2001 From: Simon Ruderich Date: Tue, 8 Apr 2014 14:38:01 +0200 Subject: [PATCH] handle_recursive: fix race condition if threads are used Requires thread-local storage. Another solution would be a mutex, but this is slower and more complicated and might cause issues with some programs. --- NEWS | 2 ++ configure.ac | 1 + m4/README | 1 + m4/ax_tls.m4 | 76 +++++++++++++++++++++++++++++++++++++++++++++ src/coloredstderr.c | 8 +++-- 5 files changed, 86 insertions(+), 2 deletions(-) create mode 100644 m4/ax_tls.m4 diff --git a/NEWS b/NEWS index 9c37519..b625510 100644 --- a/NEWS +++ b/NEWS @@ -7,6 +7,8 @@ NEWS - Fix hook for GNU's error_at_line() not exiting if status != 0. If error_one_per_line was used and suppressed a message, then error_at_line() didn't exit. +- Fix race condition when using threads. The fix requires thread-local + storage. 0.1 diff --git a/configure.ac b/configure.ac index e8d66a4..6ef50f4 100644 --- a/configure.ac +++ b/configure.ac @@ -46,6 +46,7 @@ AC_TYPE_SSIZE_T AC_C_INLINE AX_C___ATTRIBUTE__ +AX_TLS AC_CHECK_MEMBER([struct _IO_FILE._fileno], [AC_DEFINE([HAVE_STRUCT__IO_FILE__FILENO], 1, diff --git a/m4/README b/m4/README index 05e4069..bde2cea 100644 --- a/m4/README +++ b/m4/README @@ -7,3 +7,4 @@ The following files were copied unmodified from the autoconf archive [1] [1]: http://www.gnu.org/software/autoconf-archive/ - ax_c___attribute__.m4 +- ax_tls.m4 diff --git a/m4/ax_tls.m4 b/m4/ax_tls.m4 new file mode 100644 index 0000000..033e3b1 --- /dev/null +++ b/m4/ax_tls.m4 @@ -0,0 +1,76 @@ +# =========================================================================== +# http://www.gnu.org/software/autoconf-archive/ax_tls.html +# =========================================================================== +# +# SYNOPSIS +# +# AX_TLS([action-if-found], [action-if-not-found]) +# +# DESCRIPTION +# +# Provides a test for the compiler support of thread local storage (TLS) +# extensions. Defines TLS if it is found. Currently knows about GCC/ICC +# and MSVC. I think SunPro uses the same as GCC, and Borland apparently +# supports either. +# +# LICENSE +# +# Copyright (c) 2008 Alan Woodland +# Copyright (c) 2010 Diego Elio Petteno` +# +# This program is free software: you can redistribute it and/or modify it +# under the terms of the GNU General Public License as published by the +# Free Software Foundation, either version 3 of the License, or (at your +# option) any later version. +# +# This program 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 General +# Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program. If not, see . +# +# As a special exception, the respective Autoconf Macro's copyright owner +# gives unlimited permission to copy, distribute and modify the configure +# scripts that are the output of Autoconf when processing the Macro. You +# need not follow the terms of the GNU General Public License when using +# or distributing such scripts, even though portions of the text of the +# Macro appear in them. The GNU General Public License (GPL) does govern +# all other use of the material that constitutes the Autoconf Macro. +# +# This special exception to the GPL applies to versions of the Autoconf +# Macro released by the Autoconf Archive. When you make and distribute a +# modified version of the Autoconf Macro, you may extend this special +# exception to the GPL to apply to your modified version as well. + +#serial 10 + +AC_DEFUN([AX_TLS], [ + AC_MSG_CHECKING(for thread local storage (TLS) class) + AC_CACHE_VAL(ac_cv_tls, [ + ax_tls_keywords="__thread __declspec(thread) none" + for ax_tls_keyword in $ax_tls_keywords; do + AS_CASE([$ax_tls_keyword], + [none], [ac_cv_tls=none ; break], + [AC_TRY_COMPILE( + [#include + static void + foo(void) { + static ] $ax_tls_keyword [ int bar; + exit(1); + }], + [], + [ac_cv_tls=$ax_tls_keyword ; break], + ac_cv_tls=none + )]) + done + ]) + AC_MSG_RESULT($ac_cv_tls) + + AS_IF([test "$ac_cv_tls" != "none"], + AC_DEFINE_UNQUOTED([TLS], $ac_cv_tls, [If the compiler supports a TLS storage class define it to that here]) + m4_ifnblank([$1], [$1]), + m4_ifnblank([$2], [$2]) + ) +]) diff --git a/src/coloredstderr.c b/src/coloredstderr.c index c36e7d7..eaeebd3 100644 --- a/src/coloredstderr.c +++ b/src/coloredstderr.c @@ -30,6 +30,10 @@ # define NDEBUG #endif +#ifndef TLS +# define TLS +#endif + #include #include #include @@ -85,8 +89,8 @@ static int used_fds_set_by_user; * If so don't print the pre/post string for the recursive calls. This is * necessary on some systems (e.g. FreeBSD 9.1) which call multiple hooked * functions while printing a string (e.g. a FILE * and a fd hook function is - * called). */ -static int handle_recursive; + * called). This is not thread-safe if TLS is not available. */ +static TLS int handle_recursive; #include "constants.h" -- 2.43.2