1# serial 19
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) 2003-2007, 2009-2014 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([AC_CANONICAL_HOST]) dnl for cross-compiles
20  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
21  AC_CHECK_HEADERS_ONCE([unistd.h])
22  AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
23  AC_CACHE_CHECK([whether getcwd handles long file names properly],
24    gl_cv_func_getcwd_path_max,
25    [# Arrange for deletion of the temporary directory this test creates.
26     ac_clean_files="$ac_clean_files confdir3"
27     dnl Please keep this in sync with tests/test-getcwd.c.
28     AC_RUN_IFELSE(
29       [AC_LANG_SOURCE(
30          [[
31#include <errno.h>
32#include <stdlib.h>
33#if HAVE_UNISTD_H
34# include <unistd.h>
35#else
36# include <direct.h>
37#endif
38#include <string.h>
39#include <limits.h>
40#include <sys/stat.h>
41#include <sys/types.h>
42#include <fcntl.h>
43
44]gl_PATHMAX_SNIPPET[
45
46#ifndef AT_FDCWD
47# define AT_FDCWD 0
48#endif
49#ifdef ENAMETOOLONG
50# define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
51#else
52# define is_ENAMETOOLONG(x) 0
53#endif
54
55/* Use the getcwd function, not any macro.  */
56#undef getcwd
57
58/* Don't get link errors because mkdir is redefined to rpl_mkdir.  */
59#undef mkdir
60
61#ifndef S_IRWXU
62# define S_IRWXU 0700
63#endif
64
65/* The length of this name must be 8.  */
66#define DIR_NAME "confdir3"
67#define DIR_NAME_LEN 8
68#define DIR_NAME_SIZE (DIR_NAME_LEN + 1)
69
70/* The length of "../".  */
71#define DOTDOTSLASH_LEN 3
72
73/* Leftover bytes in the buffer, to work around library or OS bugs.  */
74#define BUF_SLOP 20
75
76int
77main ()
78{
79#ifndef PATH_MAX
80  /* The Hurd doesn't define this, so getcwd can't exhibit the bug --
81     at least not on a local file system.  And if we were to start worrying
82     about remote file systems, we'd have to enable the wrapper function
83     all of the time, just to be safe.  That's not worth the cost.  */
84  exit (0);
85#elif ((INT_MAX / (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1) \
86        - DIR_NAME_SIZE - BUF_SLOP) \
87       <= PATH_MAX)
88  /* FIXME: Assuming there's a system for which this is true,
89     this should be done in a compile test.  */
90  exit (0);
91#else
92  char buf[PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1)
93           + DIR_NAME_SIZE + BUF_SLOP];
94  char *cwd = getcwd (buf, PATH_MAX);
95  size_t initial_cwd_len;
96  size_t cwd_len;
97  int fail = 0;
98  size_t n_chdirs = 0;
99
100  if (cwd == NULL)
101    exit (10);
102
103  cwd_len = initial_cwd_len = strlen (cwd);
104
105  while (1)
106    {
107      size_t dotdot_max = PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN);
108      char *c = NULL;
109
110      cwd_len += DIR_NAME_SIZE;
111      /* If mkdir or chdir fails, it could be that this system cannot create
112         any file with an absolute name longer than PATH_MAX, such as cygwin.
113         If so, leave fail as 0, because the current working directory can't
114         be too long for getcwd if it can't even be created.  For other
115         errors, be pessimistic and consider that as a failure, too.  */
116      if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0)
117        {
118          if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
119            fail = 20;
120          break;
121        }
122
123      if (PATH_MAX <= cwd_len && cwd_len < PATH_MAX + DIR_NAME_SIZE)
124        {
125          c = getcwd (buf, PATH_MAX);
126          if (!c && errno == ENOENT)
127            {
128              fail = 11;
129              break;
130            }
131          if (c)
132            {
133              fail = 31;
134              break;
135            }
136          if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
137            {
138              fail = 21;
139              break;
140            }
141        }
142
143      if (dotdot_max <= cwd_len - initial_cwd_len)
144        {
145          if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len)
146            break;
147          c = getcwd (buf, cwd_len + 1);
148          if (!c)
149            {
150              if (! (errno == ERANGE || errno == ENOENT
151                     || is_ENAMETOOLONG (errno)))
152                {
153                  fail = 22;
154                  break;
155                }
156              if (AT_FDCWD || errno == ERANGE || errno == ENOENT)
157                {
158                  fail = 12;
159                  break;
160                }
161            }
162        }
163
164      if (c && strlen (c) != cwd_len)
165        {
166          fail = 23;
167          break;
168        }
169      ++n_chdirs;
170    }
171
172  /* Leaving behind such a deep directory is not polite.
173     So clean up here, right away, even though the driving
174     shell script would also clean up.  */
175  {
176    size_t i;
177
178    /* Try rmdir first, in case the chdir failed.  */
179    rmdir (DIR_NAME);
180    for (i = 0; i <= n_chdirs; i++)
181      {
182        if (chdir ("..") < 0)
183          break;
184        if (rmdir (DIR_NAME) != 0)
185          break;
186      }
187  }
188
189  exit (fail);
190#endif
191}
192          ]])],
193    [gl_cv_func_getcwd_path_max=yes],
194    [case $? in
195     10|11|12) gl_cv_func_getcwd_path_max='no, but it is partly working';;
196     31) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
197     *) gl_cv_func_getcwd_path_max=no;;
198     esac],
199    [case "$host_os" in
200       aix*) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
201       *) gl_cv_func_getcwd_path_max=no;;
202     esac])
203  ])
204])
205