Mercurial > gnulib
view lib/hash-pjw-bare.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 |
line wrap: on
line source
/* hash-pjw-bare.c -- compute a hash value from a provided buffer. 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 Lesser 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <config.h> #include "hash-pjw-bare.h" #include <limits.h> #define SIZE_BITS (sizeof (size_t) * CHAR_BIT) /* Return a hash of the N bytes of X using the method described by Bruno Haible in http://www.haible.de/bruno/hashfunc.html. Note that while many hash functions reduce their result via modulo to a 0..table_size-1 range, this function does not do that. */ size_t hash_pjw_bare (const void *x, size_t n) { const unsigned char *s = x; size_t h = 0; unsigned i; for (i = 0; i < n; i++) h = s[i] + ((h << 9) | (h >> (SIZE_BITS - 9))); return h; }