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#serial 5
# Check for several getcwd bugs with long paths.
# If so, arrange to compile the wrapper function.
# This is necessary for at least GNU libc on linux-2.4.19 and 2.4.20.
# I've heard that this is due to a Linux kernel bug, and that it has
# been fixed between 2.4.21-pre3 and 2.4.21-pre4. */
# Copyright (C) 2003, 2004 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 2, 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, write to the Free Software Foundation,
# Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
# From Jim Meyering
AC_DEFUN([gl_FUNC_GETCWD_PATH_MAX],
[
AC_CHECK_DECLS_ONCE(getcwd)
AC_CHECK_HEADERS_ONCE(fcntl.h)
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_CACHE_CHECK([whether getcwd handles long paths properly],
gl_cv_func_getcwd_path_max,
[
# Arrange for deletion of the temporary directory this test creates.
ac_clean_files="$ac_clean_files confdir3"
AC_RUN_IFELSE([AC_LANG_SOURCE([[
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <limits.h>
#include <sys/stat.h>
#include <sys/types.h>
#if HAVE_FCNTL_H
# include <fcntl.h>
#endif
#ifndef AT_FDCWD
# define AT_FDCWD 0
#endif
#ifdef ENAMETOOLONG
# define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
#else
# define is_ENAMETOOLONG(x) 0
#endif
/* Don't get link errors because mkdir is redefined to rpl_mkdir. */
#undef mkdir
#ifndef S_IRWXU
# define S_IRWXU 0700
#endif
/* The length of this name must be 8. */
#define DIR_NAME "confdir3"
#define DIR_NAME_LEN 8
#define DIR_NAME_SIZE (DIR_NAME_LEN + 1)
/* The length of "../". */
#define DOTDOTSLASH_LEN 3
/* Leftover bytes in the buffer, to work around library or OS bugs. */
#define BUF_SLOP 20
int
main (void)
{
#ifndef PATH_MAX
/* The Hurd doesn't define this, so getcwd can't exhibit the bug --
at least not on a local file system. And if we were to start worrying
about remote file systems, we'd have to enable the wrapper function
all of the time, just to be safe. That's not worth the cost. */
exit (0);
#elif ((INT_MAX / (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1) \
- DIR_NAME_SIZE - BUF_SLOP) \
<= PATH_MAX)
/* FIXME: Assuming there's a system for which this is true,
this should be done in a compile test. */
exit (0);
#else
char buf[PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1)
+ DIR_NAME_SIZE + BUF_SLOP];
char *cwd = getcwd (buf, PATH_MAX);
size_t initial_cwd_len;
size_t cwd_len;
int fail = 0;
size_t n_chdirs = 0;
if (cwd == NULL)
exit (1);
cwd_len = initial_cwd_len = strlen (cwd);
while (1)
{
size_t dotdot_max = PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN);
char *c = NULL;
cwd_len += DIR_NAME_SIZE;
/* If mkdir or chdir fails, be pessimistic and consider that
as a failure, too. */
if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0)
{
fail = 1;
break;
}
if (PATH_MAX <= cwd_len && cwd_len < PATH_MAX + DIR_NAME_SIZE)
{
c = getcwd (buf, PATH_MAX);
if (c || errno != ERANGE)
{
fail = 1;
break;
}
}
if (dotdot_max <= cwd_len - initial_cwd_len)
{
if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len)
break;
c = getcwd (buf, cwd_len + 1);
if (!c && (AT_FDCWD || !is_ENAMETOOLONG (errno)))
{
fail = 1;
break;
}
}
if (c && strlen (c) != cwd_len)
{
fail = 1;
break;
}
++n_chdirs;
}
/* Leaving behind such a deep directory is not polite.
So clean up here, right away, even though the driving
shell script would also clean up. */
{
size_t i;
/* Unlink first, in case the chdir failed. */
unlink (DIR_NAME);
for (i = 0; i <= n_chdirs; i++)
{
if (chdir ("..") < 0)
break;
rmdir (DIR_NAME);
}
}
exit (fail);
#endif
}
]])],
[gl_cv_func_getcwd_path_max=yes],
[gl_cv_func_getcwd_path_max=no],
[gl_cv_func_getcwd_path_max=no])])
])
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