1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
|
# serial 23
# Check for several getcwd bugs with long file names.
# If so, arrange to compile the wrapper function.
# This is necessary for at least GNU libc on linux-2.4.19 and 2.4.20.
# I've heard that this is due to a Linux kernel bug, and that it has
# been fixed between 2.4.21-pre3 and 2.4.21-pre4.
# Copyright (C) 2003-2007, 2009-2020 Free Software Foundation, Inc.
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
# From Jim Meyering
AC_DEFUN([gl_FUNC_GETCWD_PATH_MAX],
[
AC_CHECK_DECLS_ONCE([getcwd])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_CHECK_HEADERS_ONCE([unistd.h])
AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
AC_CACHE_CHECK([whether getcwd handles long file names properly],
[gl_cv_func_getcwd_path_max],
[# Arrange for deletion of the temporary directory this test creates.
ac_clean_files="$ac_clean_files confdir3"
dnl Please keep this in sync with tests/test-getcwd.c.
AC_RUN_IFELSE(
[AC_LANG_SOURCE(
[[
#include <errno.h>
#include <stdlib.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#else
# include <direct.h>
#endif
#include <string.h>
#include <limits.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
]gl_PATHMAX_SNIPPET[
#ifndef AT_FDCWD
# define AT_FDCWD 0
#endif
#ifdef ENAMETOOLONG
# define is_ENAMETOOLONG(x) ((x) == ENAMETOOLONG)
#else
# define is_ENAMETOOLONG(x) 0
#endif
/* Use the getcwd function, not any macro. */
#undef getcwd
/* Don't get link errors because mkdir is redefined to rpl_mkdir. */
#undef mkdir
#ifndef S_IRWXU
# define S_IRWXU 0700
#endif
/* The length of this name must be 8. */
#define DIR_NAME "confdir3"
#define DIR_NAME_LEN 8
#define DIR_NAME_SIZE (DIR_NAME_LEN + 1)
/* The length of "../". */
#define DOTDOTSLASH_LEN 3
/* Leftover bytes in the buffer, to work around library or OS bugs. */
#define BUF_SLOP 20
int
main ()
{
#ifndef PATH_MAX
/* The Hurd doesn't define this, so getcwd can't exhibit the bug --
at least not on a local file system. And if we were to start worrying
about remote file systems, we'd have to enable the wrapper function
all of the time, just to be safe. That's not worth the cost. */
exit (0);
#elif ((INT_MAX / (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1) \
- DIR_NAME_SIZE - BUF_SLOP) \
<= PATH_MAX)
/* FIXME: Assuming there's a system for which this is true,
this should be done in a compile test. */
exit (0);
#else
char buf[PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1)
+ DIR_NAME_SIZE + BUF_SLOP];
char *cwd = getcwd (buf, PATH_MAX);
size_t initial_cwd_len;
size_t cwd_len;
int fail = 0;
size_t n_chdirs = 0;
if (cwd == NULL)
exit (10);
cwd_len = initial_cwd_len = strlen (cwd);
while (1)
{
size_t dotdot_max = PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN);
char *c = NULL;
cwd_len += DIR_NAME_SIZE;
/* If mkdir or chdir fails, it could be that this system cannot create
any file with an absolute name longer than PATH_MAX, such as cygwin.
If so, leave fail as 0, because the current working directory can't
be too long for getcwd if it can't even be created. On Linux with
the 9p file system, mkdir fails with error EINVAL when cwd_len gets
too long; ignore this failure because the getcwd() system call
produces good results whereas the gnulib substitute calls getdents64
which fails with error EPROTO.
For other errors, be pessimistic and consider that as a failure,
too. */
if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0)
{
if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
#ifdef __linux__
if (! (errno == EINVAL))
#endif
fail = 20;
break;
}
if (PATH_MAX <= cwd_len && cwd_len < PATH_MAX + DIR_NAME_SIZE)
{
struct stat sb;
c = getcwd (buf, PATH_MAX);
if (!c && errno == ENOENT)
{
fail = 11;
break;
}
if (c)
{
fail = 31;
break;
}
if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
{
fail = 21;
break;
}
/* Our replacement needs to be able to stat() long ../../paths,
so generate a path larger than PATH_MAX to check,
avoiding the replacement if we can't stat(). */
c = getcwd (buf, cwd_len + 1);
if (c && !AT_FDCWD && stat (c, &sb) != 0 && is_ENAMETOOLONG (errno))
{
fail = 32;
break;
}
}
if (dotdot_max <= cwd_len - initial_cwd_len)
{
if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len)
break;
c = getcwd (buf, cwd_len + 1);
if (!c)
{
if (! (errno == ERANGE || errno == ENOENT
|| is_ENAMETOOLONG (errno)))
{
fail = 22;
break;
}
if (AT_FDCWD || errno == ERANGE || errno == ENOENT)
{
fail = 12;
break;
}
}
}
if (c && strlen (c) != cwd_len)
{
fail = 23;
break;
}
++n_chdirs;
}
/* Leaving behind such a deep directory is not polite.
So clean up here, right away, even though the driving
shell script would also clean up. */
{
size_t i;
/* Try rmdir first, in case the chdir failed. */
rmdir (DIR_NAME);
for (i = 0; i <= n_chdirs; i++)
{
if (chdir ("..") < 0)
break;
if (rmdir (DIR_NAME) != 0)
break;
}
}
exit (fail);
#endif
}
]])],
[gl_cv_func_getcwd_path_max=yes],
[case $? in
10|11|12) gl_cv_func_getcwd_path_max='no, but it is partly working';;
31) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
32) gl_cv_func_getcwd_path_max='yes, but with shorter paths';;
*) gl_cv_func_getcwd_path_max=no;;
esac],
[# Cross-compilation guesses:
case "$host_os" in
aix*) # On AIX, it has the AIX bug.
gl_cv_func_getcwd_path_max='guessing no, it has the AIX bug' ;;
gnu*) # On Hurd, it is 'yes'.
gl_cv_func_getcwd_path_max='guessing yes' ;;
linux* | kfreebsd*)
# On older Linux+glibc it's 'no, but it is partly working',
# on newer Linux+glibc it's 'yes'.
# On Linux+musl libc, it's 'no, but it is partly working'.
# On kFreeBSD+glibc, it's 'no, but it is partly working'.
gl_cv_func_getcwd_path_max='guessing no, but it is partly working' ;;
*) # If we don't know, obey --enable-cross-guesses.
gl_cv_func_getcwd_path_max="$gl_cross_guess_normal" ;;
esac
])
])
])
|
