Mercurial > gnulib
view m4/gettimeofday.m4 @ 37246:5cfb3a67238d
regex: avoid glibc deadlock during configure
glibc has a known bug where certain corruptions of the heap can
cause malloc to default to printing a debug message that includes
a backtrace, but the act of getting the backtrace uses dlopen
which in turn calls into malloc, causing a recursive lock ending
in deadlock. Thus, when configure is probing for a known glibc
heap corruption bug, the overall configure would hang.
The solution suggested by glibc developers is to force malloc
to quit printing debug messages, which avoids recursive malloc.
* m4/regex.m4 (gl_REGEX): Avoid recursive malloc deadlock when
glibc bug 15078 in turn triggers bug 16159.
Reported by Michal Privoznik.
Signed-off-by: Eric Blake <eblake@redhat.com>
author | Eric Blake <eblake@redhat.com> |
---|---|
date | Tue, 03 Dec 2013 10:34:13 -0700 |
parents | c741bc27922a |
children | 1a0eb4e01632 |
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# serial 20 # Copyright (C) 2001-2003, 2005, 2007, 2009-2013 Free Software Foundation, Inc. # This file is free software; the Free Software Foundation # gives unlimited permission to copy and/or distribute it, # with or without modifications, as long as this notice is preserved. dnl From Jim Meyering. AC_DEFUN([gl_FUNC_GETTIMEOFDAY], [ AC_REQUIRE([AC_C_RESTRICT]) AC_REQUIRE([gl_HEADER_SYS_TIME_H]) AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS]) AC_CHECK_FUNCS_ONCE([gettimeofday]) gl_gettimeofday_timezone=void if test $ac_cv_func_gettimeofday != yes; then HAVE_GETTIMEOFDAY=0 else gl_FUNC_GETTIMEOFDAY_CLOBBER AC_CACHE_CHECK([for gettimeofday with POSIX signature], [gl_cv_func_gettimeofday_posix_signature], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( [[#include <sys/time.h> struct timeval c; int gettimeofday (struct timeval *restrict, void *restrict); ]], [[/* glibc uses struct timezone * rather than the POSIX void * if _GNU_SOURCE is defined. However, since the only portable use of gettimeofday uses NULL as the second parameter, and since the glibc definition is actually more typesafe, it is not worth wrapping this to get a compliant signature. */ int (*f) (struct timeval *restrict, void *restrict) = gettimeofday; int x = f (&c, 0); return !(x | c.tv_sec | c.tv_usec); ]])], [gl_cv_func_gettimeofday_posix_signature=yes], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( [[#include <sys/time.h> int gettimeofday (struct timeval *restrict, struct timezone *restrict); ]])], [gl_cv_func_gettimeofday_posix_signature=almost], [gl_cv_func_gettimeofday_posix_signature=no])])]) if test $gl_cv_func_gettimeofday_posix_signature = almost; then gl_gettimeofday_timezone='struct timezone' elif test $gl_cv_func_gettimeofday_posix_signature != yes; then REPLACE_GETTIMEOFDAY=1 fi dnl If we override 'struct timeval', we also have to override gettimeofday. if test $REPLACE_STRUCT_TIMEVAL = 1; then REPLACE_GETTIMEOFDAY=1 fi m4_ifdef([gl_FUNC_TZSET_CLOBBER], [ gl_FUNC_TZSET_CLOBBER case "$gl_cv_func_tzset_clobber" in *yes) REPLACE_GETTIMEOFDAY=1 gl_GETTIMEOFDAY_REPLACE_LOCALTIME AC_DEFINE([tzset], [rpl_tzset], [Define to rpl_tzset if the wrapper function should be used.]) AC_DEFINE([TZSET_CLOBBERS_LOCALTIME], [1], [Define if tzset clobbers localtime's static buffer.]) ;; esac ]) fi AC_DEFINE_UNQUOTED([GETTIMEOFDAY_TIMEZONE], [$gl_gettimeofday_timezone], [Define this to 'void' or 'struct timezone' to match the system's declaration of the second argument to gettimeofday.]) ]) dnl See if gettimeofday clobbers the static buffer that localtime uses dnl for its return value. The gettimeofday function from Mac OS X 10.0.4 dnl (i.e., Darwin 1.3.7) has this problem. dnl dnl If it does, then arrange to use gettimeofday and localtime only via dnl the wrapper functions that work around the problem. AC_DEFUN([gl_FUNC_GETTIMEOFDAY_CLOBBER], [ AC_REQUIRE([gl_HEADER_SYS_TIME_H]) AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles AC_CACHE_CHECK([whether gettimeofday clobbers localtime buffer], [gl_cv_func_gettimeofday_clobber], [AC_RUN_IFELSE( [AC_LANG_PROGRAM( [[#include <string.h> #include <sys/time.h> #include <time.h> #include <stdlib.h> ]], [[ time_t t = 0; struct tm *lt; struct tm saved_lt; struct timeval tv; lt = localtime (&t); saved_lt = *lt; gettimeofday (&tv, NULL); return memcmp (lt, &saved_lt, sizeof (struct tm)) != 0; ]])], [gl_cv_func_gettimeofday_clobber=no], [gl_cv_func_gettimeofday_clobber=yes], [# When cross-compiling: case "$host_os" in # Guess all is fine on glibc systems. *-gnu*) gl_cv_func_gettimeofday_clobber="guessing no" ;; # If we don't know, assume the worst. *) gl_cv_func_gettimeofday_clobber="guessing yes" ;; esac ])]) case "$gl_cv_func_gettimeofday_clobber" in *yes) REPLACE_GETTIMEOFDAY=1 gl_GETTIMEOFDAY_REPLACE_LOCALTIME AC_DEFINE([GETTIMEOFDAY_CLOBBERS_LOCALTIME], [1], [Define if gettimeofday clobbers the localtime buffer.]) ;; esac ]) AC_DEFUN([gl_GETTIMEOFDAY_REPLACE_LOCALTIME], [ AC_DEFINE([gmtime], [rpl_gmtime], [Define to rpl_gmtime if the replacement function should be used.]) AC_DEFINE([localtime], [rpl_localtime], [Define to rpl_localtime if the replacement function should be used.]) ]) # Prerequisites of lib/gettimeofday.c. AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [ AC_CHECK_HEADERS([sys/timeb.h]) AC_CHECK_FUNCS([_ftime]) ])