Mercurial > gnulib
view m4/expm1f.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 | 344018b6e5d7 |
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# expm1f.m4 serial 2 dnl Copyright (C) 2011-2013 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. AC_DEFUN([gl_FUNC_EXPM1F], [ AC_REQUIRE([gl_MATH_H_DEFAULTS]) AC_REQUIRE([gl_FUNC_EXPM1]) dnl Persuade glibc <math.h> to declare expm1f(). AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) dnl Test whether expm1f() exists. Assume that expm1f(), if it exists, is dnl defined in the same library as expm1(). save_LIBS="$LIBS" LIBS="$LIBS $EXPM1_LIBM" AC_CHECK_FUNCS([expm1f]) LIBS="$save_LIBS" if test $ac_cv_func_expm1f = yes; then EXPM1F_LIBM="$EXPM1_LIBM" save_LIBS="$LIBS" LIBS="$LIBS $EXPM1F_LIBM" gl_FUNC_EXPM1F_WORKS LIBS="$save_LIBS" case "$gl_cv_func_expm1f_works" in *yes) ;; *) REPLACE_EXPM1F=1 ;; esac else HAVE_EXPM1F=0 fi if test $HAVE_EXPM1F = 0 || test $REPLACE_EXPM1F = 1; then dnl Find libraries needed to link lib/expm1f.c. EXPM1F_LIBM="$EXPM1_LIBM" fi AC_SUBST([EXPM1F_LIBM]) ]) dnl Test whether expm1f() works. dnl On IRIX 6.5, for arguments <= -17.32868, it returns -5.6295e14. AC_DEFUN([gl_FUNC_EXPM1F_WORKS], [ AC_REQUIRE([AC_PROG_CC]) AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles AC_CACHE_CHECK([whether expm1f works], [gl_cv_func_expm1f_works], [ AC_RUN_IFELSE( [AC_LANG_SOURCE([[ #include <math.h> volatile float x; float y; int main () { x = -100.0f; y = expm1f (x); if (y < -1.0f) return 1; return 0; } ]])], [gl_cv_func_expm1f_works=yes], [gl_cv_func_expm1f_works=no], [case "$host_os" in irix*) gl_cv_func_expm1f_works="guessing no";; *) gl_cv_func_expm1f_works="guessing yes";; esac ]) ]) ])