view m4/rmdir-errno.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
line wrap: on
line source

# serial 10

# Copyright (C) 2000-2001, 2005-2006, 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.

# When rmdir fails because the specified directory is not empty, it sets
# errno to some value, usually ENOTEMPTY.  However, on some AIX systems,
# ENOTEMPTY is mistakenly defined to be EEXIST.  To work around this, and
# in general, to avoid depending on the use of any particular symbol, this
# test runs a test to determine the actual numeric value.
AC_DEFUN([gl_FUNC_RMDIR_NOTEMPTY],
[dnl
  AC_CHECK_HEADERS_ONCE([unistd.h])
  AC_CACHE_CHECK([for rmdir-not-empty errno value],
    gl_cv_func_rmdir_errno_not_empty,
    [
      # Arrange for deletion of the temporary directory this test creates.
      ac_clean_files="$ac_clean_files confdir2"
      mkdir confdir2; : > confdir2/file
      AC_RUN_IFELSE([AC_LANG_SOURCE([[
#include <stdio.h>
#include <errno.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
        int main ()
        {
          FILE *s;
          int val;
          rmdir ("confdir2");
          val = errno;
          s = fopen ("confdir2/errno", "w");
          fprintf (s, "%d\n", val);
          return 0;
        }
        ]])],
      [gl_cv_func_rmdir_errno_not_empty=`cat confdir2/errno`],
      [gl_cv_func_rmdir_errno_not_empty='configure error in rmdir-errno.m4'],
      [gl_cv_func_rmdir_errno_not_empty=ENOTEMPTY]
      )
    ]
  )

  AC_DEFINE_UNQUOTED([RMDIR_ERRNO_NOT_EMPTY],
    $gl_cv_func_rmdir_errno_not_empty,
    [the value to which errno is set when rmdir fails on a nonempty directory])
])