| 1 | # serial 23 |
| 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, 2009-2019 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 | |
| 16 | AC_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 | |
| 76 | int |
| 77 | main () |
| 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. On Linux with |
| 115 | the 9p file system, mkdir fails with error EINVAL when cwd_len gets |
| 116 | too long; ignore this failure because the getcwd() system call |
| 117 | produces good results whereas the gnulib substitute calls getdents64 |
| 118 | which fails with error EPROTO. |
| 119 | For other errors, be pessimistic and consider that as a failure, |
| 120 | too. */ |
| 121 | if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0) |
| 122 | { |
| 123 | if (! (errno == ERANGE || is_ENAMETOOLONG (errno))) |
| 124 | #ifdef __linux__ |
| 125 | if (! (errno == EINVAL)) |
| 126 | #endif |
| 127 | fail = 20; |
| 128 | break; |
| 129 | } |
| 130 | |
| 131 | if (PATH_MAX <= cwd_len && cwd_len < PATH_MAX + DIR_NAME_SIZE) |
| 132 | { |
| 133 | struct stat sb; |
| 134 | |
| 135 | c = getcwd (buf, PATH_MAX); |
| 136 | if (!c && errno == ENOENT) |
| 137 | { |
| 138 | fail = 11; |
| 139 | break; |
| 140 | } |
| 141 | if (c) |
| 142 | { |
| 143 | fail = 31; |
| 144 | break; |
| 145 | } |
| 146 | if (! (errno == ERANGE || is_ENAMETOOLONG (errno))) |
| 147 | { |
| 148 | fail = 21; |
| 149 | break; |
| 150 | } |
| 151 | |
| 152 | /* Our replacement needs to be able to stat() long ../../paths, |
| 153 | so generate a path larger than PATH_MAX to check, |
| 154 | avoiding the replacement if we can't stat(). */ |
| 155 | c = getcwd (buf, cwd_len + 1); |
| 156 | if (c && !AT_FDCWD && stat (c, &sb) != 0 && is_ENAMETOOLONG (errno)) |
| 157 | { |
| 158 | fail = 32; |
| 159 | break; |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | if (dotdot_max <= cwd_len - initial_cwd_len) |
| 164 | { |
| 165 | if (dotdot_max + DIR_NAME_SIZE < cwd_len - initial_cwd_len) |
| 166 | break; |
| 167 | c = getcwd (buf, cwd_len + 1); |
| 168 | if (!c) |
| 169 | { |
| 170 | if (! (errno == ERANGE || errno == ENOENT |
| 171 | || is_ENAMETOOLONG (errno))) |
| 172 | { |
| 173 | fail = 22; |
| 174 | break; |
| 175 | } |
| 176 | if (AT_FDCWD || errno == ERANGE || errno == ENOENT) |
| 177 | { |
| 178 | fail = 12; |
| 179 | break; |
| 180 | } |
| 181 | } |
| 182 | } |
| 183 | |
| 184 | if (c && strlen (c) != cwd_len) |
| 185 | { |
| 186 | fail = 23; |
| 187 | break; |
| 188 | } |
| 189 | ++n_chdirs; |
| 190 | } |
| 191 | |
| 192 | /* Leaving behind such a deep directory is not polite. |
| 193 | So clean up here, right away, even though the driving |
| 194 | shell script would also clean up. */ |
| 195 | { |
| 196 | size_t i; |
| 197 | |
| 198 | /* Try rmdir first, in case the chdir failed. */ |
| 199 | rmdir (DIR_NAME); |
| 200 | for (i = 0; i <= n_chdirs; i++) |
| 201 | { |
| 202 | if (chdir ("..") < 0) |
| 203 | break; |
| 204 | if (rmdir (DIR_NAME) != 0) |
| 205 | break; |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | exit (fail); |
| 210 | #endif |
| 211 | } |
| 212 | ]])], |
| 213 | [gl_cv_func_getcwd_path_max=yes], |
| 214 | [case $? in |
| 215 | 10|11|12) gl_cv_func_getcwd_path_max='no, but it is partly working';; |
| 216 | 31) gl_cv_func_getcwd_path_max='no, it has the AIX bug';; |
| 217 | 32) gl_cv_func_getcwd_path_max='yes, but with shorter paths';; |
| 218 | *) gl_cv_func_getcwd_path_max=no;; |
| 219 | esac], |
| 220 | [# Cross-compilation guesses: |
| 221 | case "$host_os" in |
| 222 | aix*) # On AIX, it has the AIX bug. |
| 223 | gl_cv_func_getcwd_path_max='guessing no, it has the AIX bug' ;; |
| 224 | gnu*) # On Hurd, it is 'yes'. |
| 225 | gl_cv_func_getcwd_path_max='guessing yes' ;; |
| 226 | linux* | kfreebsd*) |
| 227 | # On older Linux+glibc it's 'no, but it is partly working', |
| 228 | # on newer Linux+glibc it's 'yes'. |
| 229 | # On Linux+musl libc, it's 'no, but it is partly working'. |
| 230 | # On kFreeBSD+glibc, it's 'no, but it is partly working'. |
| 231 | gl_cv_func_getcwd_path_max='guessing no, but it is partly working' ;; |
| 232 | *) # If we don't know, obey --enable-cross-guesses. |
| 233 | gl_cv_func_getcwd_path_max="$gl_cross_guess_normal" ;; |
| 234 | esac |
| 235 | ]) |
| 236 | ]) |
| 237 | ]) |