1#serial 10
2# Check for several getcwd bugs with long file names.
3# If so, arrange to compile the wrapper function.
4
5# This is necessary for at least GNU libc on linux-2.4.19 and 2.4.20.
6# I've heard that this is due to a Linux kernel bug, and that it has
7# been fixed between 2.4.21-pre3 and 2.4.21-pre4.  */
8
9# Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
10# This file is free software; the Free Software Foundation
11# gives unlimited permission to copy and/or distribute it,
12# with or without modifications, as long as this notice is preserved.
13
14# From Jim Meyering
15
16AC_DEFUN([gl_FUNC_GETCWD_PATH_MAX],
17[
18  AC_CHECK_DECLS_ONCE(getcwd)
19  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
20  AC_CACHE_CHECK([whether getcwd handles long file names properly],
21    gl_cv_func_getcwd_path_max,
22    [# Arrange for deletion of the temporary directory this test creates.
23     ac_clean_files="$ac_clean_files confdir3"
24     AC_RUN_IFELSE(
25       [AC_LANG_SOURCE(
26            [[
27#include <errno.h>
28#include <stdlib.h>
29#include <unistd.h>
30#include <string.h>
31#include <limits.h>
32#include <sys/stat.h>
33#include <sys/types.h>
34#include <fcntl.h>
35
36#ifndef AT_FDCWD
37# define AT_FDCWD 0
38#endif
39#ifdef ENAMETOOLONG
40# define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
41#else
42# define is_ENAMETOOLONG(x) 0
43#endif
44
45/* Don't get link errors because mkdir is redefined to rpl_mkdir.  */
46#undef mkdir
47
48#ifndef S_IRWXU
49# define S_IRWXU 0700
50#endif
51
52/* The length of this name must be 8.  */
53#define DIR_NAME "confdir3"
54#define DIR_NAME_LEN 8
55#define DIR_NAME_SIZE (DIR_NAME_LEN + 1)
56
57/* The length of "../".  */
58#define DOTDOTSLASH_LEN 3
59
60/* Leftover bytes in the buffer, to work around library or OS bugs.  */
61#define BUF_SLOP 20
62
63int
64main (void)
65{
66#ifndef PATH_MAX
67  /* The Hurd doesn't define this, so getcwd can't exhibit the bug --
68     at least not on a local file system.  And if we were to start worrying
69     about remote file systems, we'd have to enable the wrapper function
70     all of the time, just to be safe.  That's not worth the cost.  */
71  exit (0);
72#elif ((INT_MAX / (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1) \
73        - DIR_NAME_SIZE - BUF_SLOP) \
74       <= PATH_MAX)
75  /* FIXME: Assuming there's a system for which this is true,
76     this should be done in a compile test.  */
77  exit (0);
78#else
79  char buf[PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1)
80             + DIR_NAME_SIZE + BUF_SLOP];
81  char *cwd = getcwd (buf, PATH_MAX);
82  size_t initial_cwd_len;
83  size_t cwd_len;
84  int fail = 0;
85  size_t n_chdirs = 0;
86
87  if (cwd == NULL)
88    exit (1);
89
90  cwd_len = initial_cwd_len = strlen (cwd);
91
92  while (1)
93    {
94      size_t dotdot_max = PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN);
95      char *c = NULL;
96
97      cwd_len += DIR_NAME_SIZE;
98      /* If mkdir or chdir fails, it could be that this system cannot create
99           any file with an absolute name longer than PATH_MAX, such as cygwin.
100           If so, leave fail as 0, because the current working directory can't
101           be too long for getcwd if it can't even be created.  For other
102           errors, be pessimistic and consider that as a failure, too.  */
103      if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0)
104          {
105            if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
106              fail = 2;
107            break;
108          }
109
110      if (PATH_MAX <= cwd_len && cwd_len < PATH_MAX + DIR_NAME_SIZE)
111          {
112            c = getcwd (buf, PATH_MAX);
113            if (!c && errno == ENOENT)
114              {
115                fail = 1;
116                break;
117              }
118            if (c || ! (errno == ERANGE || is_ENAMETOOLONG (errno)))
119              {
120                fail = 2;
121                break;
122              }
123          }
124
125      if (dotdot_max <= cwd_len - initial_cwd_len)
126          {
127            if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len)
128              break;
129            c = getcwd (buf, cwd_len + 1);
130            if (!c)
131              {
132                if (! (errno == ERANGE || errno == ENOENT
133                         || is_ENAMETOOLONG (errno)))
134                    {
135                      fail = 2;
136                      break;
137                    }
138                if (AT_FDCWD || errno == ERANGE || errno == ENOENT)
139                    {
140                      fail = 1;
141                      break;
142                    }
143              }
144          }
145
146      if (c && strlen (c) != cwd_len)
147          {
148            fail = 2;
149            break;
150          }
151      ++n_chdirs;
152    }
153
154  /* Leaving behind such a deep directory is not polite.
155     So clean up here, right away, even though the driving
156     shell script would also clean up.  */
157  {
158    size_t i;
159
160    /* Unlink first, in case the chdir failed.  */
161    unlink (DIR_NAME);
162    for (i = 0; i <= n_chdirs; i++)
163      {
164          if (chdir ("..") < 0)
165            break;
166          rmdir (DIR_NAME);
167      }
168  }
169
170  exit (fail);
171#endif
172}
173          ]])],
174    [gl_cv_func_getcwd_path_max=yes],
175    [case $? in
176     1) gl_cv_func_getcwd_path_max='no, but it is partly working';;
177     *) gl_cv_func_getcwd_path_max=no;;
178     esac],
179    [gl_cv_func_getcwd_path_max=no])
180  ])
181  case $gl_cv_func_getcwd_path_max in
182  no,*)
183    AC_DEFINE([HAVE_PARTLY_WORKING_GETCWD], 1,
184      [Define to 1 if getcwd works, except it sometimes fails when it shouldn't,
185       setting errno to ERANGE, ENAMETOOLONG, or ENOENT.  If __GETCWD_PREFIX
186       is not defined, it doesn't matter whether HAVE_PARTLY_WORKING_GETCWD
187       is defined.]);;
188  esac
189])
190