Mercurial > gnulib
view lib/ilogb.c @ 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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/* Floating-point exponent. Copyright (C) 2012-2013 Free Software Foundation, Inc. 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 <http://www.gnu.org/licenses/>. */ #if ! (defined USE_LONG_DOUBLE || defined USE_FLOAT) # include <config.h> #endif /* Specification. */ #include <math.h> #include <limits.h> #ifdef USE_LONG_DOUBLE # define ILOGB ilogbl # define DOUBLE long double # define L_(literal) literal##L # define FREXP frexpl # define ISNAN isnanl #elif ! defined USE_FLOAT # define ILOGB ilogb # define DOUBLE double # define L_(literal) literal # define FREXP frexp # define ISNAN isnand #else /* defined USE_FLOAT */ # define ILOGB ilogbf # define DOUBLE float # define L_(literal) literal##f # define FREXP frexpf # define ISNAN isnanf #endif int ILOGB (DOUBLE x) { if (isfinite (x)) { if (x == L_(0.0)) return FP_ILOGB0; else { int e; (void) FREXP (x, &e); return e - 1; } } else { if (ISNAN (x)) return FP_ILOGBNAN; else return INT_MAX; } }