1# serial 7
2# Determine whether getcwd aborts when the length of the working directory
3# name is unusually large.  Any length between 4k and 16k trigger the bug
4# when using glibc-2.4.90-9 or older.
5
6# Copyright (C) 2006, 2009-2012 Free Software Foundation, Inc.
7# This file is free software; the Free Software Foundation
8# gives unlimited permission to copy and/or distribute it,
9# with or without modifications, as long as this notice is preserved.
10
11# From Jim Meyering
12
13# gl_FUNC_GETCWD_ABORT_BUG([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
14AC_DEFUN([gl_FUNC_GETCWD_ABORT_BUG],
15[
16  AC_CHECK_DECLS_ONCE([getcwd])
17  AC_CHECK_HEADERS_ONCE([unistd.h])
18  AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
19  AC_CHECK_FUNCS([getpagesize])
20  AC_CACHE_CHECK([whether getcwd aborts when 4k < cwd_length < 16k],
21    gl_cv_func_getcwd_abort_bug,
22    [# Remove any remnants of a previous test.
23     rm -rf confdir-14B---
24     # Arrange for deletion of the temporary directory this test creates.
25     ac_clean_files="$ac_clean_files confdir-14B---"
26     dnl Please keep this in sync with tests/test-getcwd.c.
27     AC_RUN_IFELSE(
28       [AC_LANG_SOURCE(
29          [[
30#include <stdlib.h>
31#if HAVE_UNISTD_H
32# include <unistd.h>
33#else /* on Windows with MSVC */
34# include <direct.h>
35#endif
36#include <string.h>
37#include <sys/stat.h>
38
39]gl_PATHMAX_SNIPPET[
40
41/* Don't get link errors because mkdir is redefined to rpl_mkdir.  */
42#undef mkdir
43
44#ifndef S_IRWXU
45# define S_IRWXU 0700
46#endif
47
48/* FIXME: skip the run-test altogether on systems without getpagesize.  */
49#if ! HAVE_GETPAGESIZE
50# define getpagesize() 0
51#endif
52
53/* This size is chosen to be larger than PATH_MAX (4k), yet smaller than
54   the 16kB pagesize on ia64 linux.  Those conditions make the code below
55   trigger a bug in glibc's getcwd implementation before 2.4.90-10.  */
56#define TARGET_LEN (5 * 1024)
57
58int
59main ()
60{
61  char const *dir_name = "confdir-14B---";
62  char *cwd;
63  size_t initial_cwd_len;
64  int fail = 0;
65  size_t desired_depth;
66  size_t d;
67
68  /* The bug is triggered when PATH_MAX < getpagesize (), so skip
69     this relatively expensive and invasive test if that's not true.  */
70  if (getpagesize () <= PATH_MAX)
71    return 0;
72
73  cwd = getcwd (NULL, 0);
74  if (cwd == NULL)
75    return 2;
76
77  initial_cwd_len = strlen (cwd);
78  free (cwd);
79  desired_depth = ((TARGET_LEN - 1 - initial_cwd_len)
80                   / (1 + strlen (dir_name)));
81  for (d = 0; d < desired_depth; d++)
82    {
83      if (mkdir (dir_name, S_IRWXU) < 0 || chdir (dir_name) < 0)
84        {
85          fail = 3; /* Unable to construct deep hierarchy.  */
86          break;
87        }
88    }
89
90  /* If libc has the bug in question, this invocation of getcwd
91     results in a failed assertion.  */
92  cwd = getcwd (NULL, 0);
93  if (cwd == NULL)
94    fail = 4; /* getcwd failed: it refuses to return a string longer
95                 than PATH_MAX.  */
96  free (cwd);
97
98  /* Call rmdir first, in case the above chdir failed.  */
99  rmdir (dir_name);
100  while (0 < d--)
101    {
102      if (chdir ("..") < 0)
103        {
104          fail = 5;
105          break;
106        }
107      rmdir (dir_name);
108    }
109
110  return fail;
111}
112          ]])],
113    [gl_cv_func_getcwd_abort_bug=no],
114    [dnl An abort will provoke an exit code of something like 134 (128 + 6).
115     dnl An exit code of 4 can also occur (in OpenBSD 4.9, NetBSD 5.1 for
116     dnl example): getcwd (NULL, 0) fails rather than returning a string
117     dnl longer than PATH_MAX.  This may be POSIX compliant (in some
118     dnl interpretations of POSIX).  But gnulib's getcwd module wants to
119     dnl provide a non-NULL value in this case.
120     ret=$?
121     if test $ret -ge 128 || test $ret = 4; then
122       gl_cv_func_getcwd_abort_bug=yes
123     else
124       gl_cv_func_getcwd_abort_bug=no
125     fi],
126    [gl_cv_func_getcwd_abort_bug=yes])
127  ])
128  AS_IF([test $gl_cv_func_getcwd_abort_bug = yes], [$1], [$2])
129])
130