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, 2009-2015 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          struct stat sb;
126
127          c = getcwd (buf, PATH_MAX);
128          if (!c && errno == ENOENT)
129            {
130              fail = 11;
131              break;
132            }
133          if (c)
134            {
135              fail = 31;
136              break;
137            }
138          if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
139            {
140              fail = 21;
141              break;
142            }
143
144          /* Our replacement needs to be able to stat() long ../../paths,
145             so generate a path larger than PATH_MAX to check,
146             avoiding the replacement if we can't stat().  */
147          c = getcwd (buf, cwd_len + 1);
148          if (c && !AT_FDCWD && stat (c, &sb) != 0 && is_ENAMETOOLONG (errno))
149            {
150              fail = 32;
151              break;
152            }
153        }
154
155      if (dotdot_max <= cwd_len - initial_cwd_len)
156        {
157          if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len)
158            break;
159          c = getcwd (buf, cwd_len + 1);
160          if (!c)
161            {
162              if (! (errno == ERANGE || errno == ENOENT
163                     || is_ENAMETOOLONG (errno)))
164                {
165                  fail = 22;
166                  break;
167                }
168              if (AT_FDCWD || errno == ERANGE || errno == ENOENT)
169                {
170                  fail = 12;
171                  break;
172                }
173            }
174        }
175
176      if (c && strlen (c) != cwd_len)
177        {
178          fail = 23;
179          break;
180        }
181      ++n_chdirs;
182    }
183
184  /* Leaving behind such a deep directory is not polite.
185     So clean up here, right away, even though the driving
186     shell script would also clean up.  */
187  {
188    size_t i;
189
190    /* Try rmdir first, in case the chdir failed.  */
191    rmdir (DIR_NAME);
192    for (i = 0; i <= n_chdirs; i++)
193      {
194        if (chdir ("..") < 0)
195          break;
196        if (rmdir (DIR_NAME) != 0)
197          break;
198      }
199  }
200
201  exit (fail);
202#endif
203}
204          ]])],
205    [gl_cv_func_getcwd_path_max=yes],
206    [case $? in
207     10|11|12) gl_cv_func_getcwd_path_max='no, but it is partly working';;
208     31) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
209     32) gl_cv_func_getcwd_path_max='yes, but with shorter paths';;
210     *) gl_cv_func_getcwd_path_max=no;;
211     esac],
212    [case "$host_os" in
213       aix*) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
214       *) gl_cv_func_getcwd_path_max=no;;
215     esac])
216  ])
217])
218