236 lines
7 KiB
Text
236 lines
7 KiB
Text
# serial 25
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# Check for several getcwd bugs with long file names.
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# If so, arrange to compile the wrapper function.
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# This is necessary for at least GNU libc on linux-2.4.19 and 2.4.20.
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# I've heard that this is due to a Linux kernel bug, and that it has
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# been fixed between 2.4.21-pre3 and 2.4.21-pre4.
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# Copyright (C) 2003-2007, 2009-2021 Free Software Foundation, Inc.
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# This file is free software; the Free Software Foundation
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# gives unlimited permission to copy and/or distribute it,
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# with or without modifications, as long as this notice is preserved.
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# From Jim Meyering
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AC_DEFUN([gl_FUNC_GETCWD_PATH_MAX],
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[
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AC_CHECK_DECLS_ONCE([getcwd])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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AC_CHECK_HEADERS_ONCE([unistd.h])
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AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
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AC_CACHE_CHECK([whether getcwd handles long file names properly],
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[gl_cv_func_getcwd_path_max],
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[# Arrange for deletion of the temporary directory this test creates.
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ac_clean_files="$ac_clean_files confdir3"
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dnl Please keep this in sync with tests/test-getcwd.c.
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AC_RUN_IFELSE(
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[AC_LANG_SOURCE(
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[[
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#include <errno.h>
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#include <stdlib.h>
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#if HAVE_UNISTD_H
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# include <unistd.h>
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#else
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# include <direct.h>
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#endif
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#include <string.h>
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#include <limits.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <fcntl.h>
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]gl_PATHMAX_SNIPPET[
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#ifndef AT_FDCWD
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# define AT_FDCWD 0
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#endif
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#ifdef ENAMETOOLONG
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# define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
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#else
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# define is_ENAMETOOLONG(x) 0
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#endif
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/* Use the getcwd function, not any macro. */
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#undef getcwd
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]GL_MDA_DEFINES[
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#ifndef S_IRWXU
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# define S_IRWXU 0700
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#endif
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/* The length of this name must be 8. */
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#define DIR_NAME "confdir3"
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#define DIR_NAME_LEN 8
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#define DIR_NAME_SIZE (DIR_NAME_LEN + 1)
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/* The length of "../". */
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#define DOTDOTSLASH_LEN 3
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/* Leftover bytes in the buffer, to work around library or OS bugs. */
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#define BUF_SLOP 20
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int
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main ()
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{
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#ifndef PATH_MAX
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/* The Hurd doesn't define this, so getcwd can't exhibit the bug --
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at least not on a local file system. And if we were to start worrying
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about remote file systems, we'd have to enable the wrapper function
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all of the time, just to be safe. That's not worth the cost. */
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exit (0);
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#elif ((INT_MAX / (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1) \
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- DIR_NAME_SIZE - BUF_SLOP) \
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<= PATH_MAX)
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/* FIXME: Assuming there's a system for which this is true,
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this should be done in a compile test. */
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exit (0);
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#else
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char buf[PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1)
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+ DIR_NAME_SIZE + BUF_SLOP];
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char *cwd = getcwd (buf, PATH_MAX);
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size_t initial_cwd_len;
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size_t cwd_len;
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int fail = 0;
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size_t n_chdirs = 0;
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if (cwd == NULL)
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exit (10);
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cwd_len = initial_cwd_len = strlen (cwd);
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while (1)
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{
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size_t dotdot_max = PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN);
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char *c = NULL;
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cwd_len += DIR_NAME_SIZE;
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/* If mkdir or chdir fails, it could be that this system cannot create
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any file with an absolute name longer than PATH_MAX, such as cygwin.
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If so, leave fail as 0, because the current working directory can't
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be too long for getcwd if it can't even be created. On Linux with
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the 9p file system, mkdir fails with error EINVAL when cwd_len gets
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too long; ignore this failure because the getcwd() system call
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produces good results whereas the gnulib substitute calls getdents64
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which fails with error EPROTO.
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For other errors, be pessimistic and consider that as a failure,
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too. */
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if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0)
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{
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if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
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#ifdef __linux__
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if (! (errno == EINVAL))
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#endif
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fail = 20;
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break;
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}
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if (PATH_MAX <= cwd_len && cwd_len < PATH_MAX + DIR_NAME_SIZE)
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{
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struct stat sb;
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c = getcwd (buf, PATH_MAX);
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if (!c && errno == ENOENT)
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{
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fail = 11;
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break;
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}
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if (c)
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{
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fail = 31;
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break;
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}
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if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
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{
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fail = 21;
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break;
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}
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/* Our replacement needs to be able to stat() long ../../paths,
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so generate a path larger than PATH_MAX to check,
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avoiding the replacement if we can't stat(). */
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c = getcwd (buf, cwd_len + 1);
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if (c && !AT_FDCWD && stat (c, &sb) != 0 && is_ENAMETOOLONG (errno))
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{
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fail = 32;
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break;
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}
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}
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if (dotdot_max <= cwd_len - initial_cwd_len)
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{
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if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len)
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break;
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c = getcwd (buf, cwd_len + 1);
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if (!c)
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{
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if (! (errno == ERANGE || errno == ENOENT
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|| is_ENAMETOOLONG (errno)))
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{
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fail = 22;
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break;
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}
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if (AT_FDCWD || errno == ERANGE || errno == ENOENT)
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{
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fail = 12;
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break;
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}
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}
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}
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if (c && strlen (c) != cwd_len)
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{
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fail = 23;
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break;
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}
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++n_chdirs;
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}
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/* Leaving behind such a deep directory is not polite.
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So clean up here, right away, even though the driving
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shell script would also clean up. */
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{
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size_t i;
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/* Try rmdir first, in case the chdir failed. */
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rmdir (DIR_NAME);
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for (i = 0; i <= n_chdirs; i++)
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{
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if (chdir ("..") < 0)
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break;
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if (rmdir (DIR_NAME) != 0)
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break;
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}
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}
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exit (fail);
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#endif
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}
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]])],
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[gl_cv_func_getcwd_path_max=yes],
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[case $? in
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10|11|12) gl_cv_func_getcwd_path_max='no, but it is partly working';;
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31) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
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32) gl_cv_func_getcwd_path_max='yes, but with shorter paths';;
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*) gl_cv_func_getcwd_path_max=no;;
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esac],
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[# Cross-compilation guesses:
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case "$host_os" in
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aix*) # On AIX, it has the AIX bug.
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gl_cv_func_getcwd_path_max='guessing no, it has the AIX bug' ;;
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gnu*) # On Hurd, it is 'yes'.
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gl_cv_func_getcwd_path_max='guessing yes' ;;
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linux* | kfreebsd*)
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# On older Linux+glibc it's 'no, but it is partly working',
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# on newer Linux+glibc it's 'yes'.
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# On Linux+musl libc, it's 'no, but it is partly working'.
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# On kFreeBSD+glibc, it's 'no, but it is partly working'.
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gl_cv_func_getcwd_path_max='guessing no, but it is partly working' ;;
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*) # If we don't know, obey --enable-cross-guesses.
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gl_cv_func_getcwd_path_max="$gl_cross_guess_normal" ;;
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esac
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])
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])
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])
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