1# serial 22 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 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. 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='no, it has the AIX bug' ;; 224 gnu*) # On Hurd, it is 'yes'. 225 gl_cv_func_getcwd_path_max=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='no, but it is partly working' ;; 232 *) # If we don't know, assume the worst. 233 gl_cv_func_getcwd_path_max=no ;; 234 esac 235 ]) 236 ]) 237]) 238