| 1 | /* Emulate link on platforms that lack it, namely native Windows platforms. |
| 2 | |
| 3 | Copyright (C) 2009-2014 Free Software Foundation, Inc. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU Lesser General Public License as published by |
| 7 | the Free Software Foundation; either version 2, or (at your option) |
| 8 | any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public License |
| 16 | along with this program; if not, see <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | #include <config.h> |
| 19 | |
| 20 | #include <unistd.h> |
| 21 | |
| 22 | #include <errno.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <string.h> |
| 25 | #include <sys/stat.h> |
| 26 | |
| 27 | #if !HAVE_LINK |
| 28 | # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ |
| 29 | |
| 30 | # define WIN32_LEAN_AND_MEAN |
| 31 | # include <windows.h> |
| 32 | |
| 33 | /* CreateHardLink was introduced only in Windows 2000. */ |
| 34 | typedef BOOL (WINAPI * CreateHardLinkFuncType) (LPCTSTR lpFileName, |
| 35 | LPCTSTR lpExistingFileName, |
| 36 | LPSECURITY_ATTRIBUTES lpSecurityAttributes); |
| 37 | static CreateHardLinkFuncType CreateHardLinkFunc = NULL; |
| 38 | static BOOL initialized = FALSE; |
| 39 | |
| 40 | static void |
| 41 | initialize (void) |
| 42 | { |
| 43 | HMODULE kernel32 = GetModuleHandle ("kernel32.dll"); |
| 44 | if (kernel32 != NULL) |
| 45 | { |
| 46 | CreateHardLinkFunc = |
| 47 | (CreateHardLinkFuncType) GetProcAddress (kernel32, "CreateHardLinkA"); |
| 48 | } |
| 49 | initialized = TRUE; |
| 50 | } |
| 51 | |
| 52 | int |
| 53 | link (const char *file1, const char *file2) |
| 54 | { |
| 55 | char *dir; |
| 56 | size_t len1 = strlen (file1); |
| 57 | size_t len2 = strlen (file2); |
| 58 | if (!initialized) |
| 59 | initialize (); |
| 60 | if (CreateHardLinkFunc == NULL) |
| 61 | { |
| 62 | /* System does not support hard links. */ |
| 63 | errno = EPERM; |
| 64 | return -1; |
| 65 | } |
| 66 | /* Reject trailing slashes on non-directories; mingw does not |
| 67 | support hard-linking directories. */ |
| 68 | if ((len1 && (file1[len1 - 1] == '/' || file1[len1 - 1] == '\\')) |
| 69 | || (len2 && (file2[len2 - 1] == '/' || file2[len2 - 1] == '\\'))) |
| 70 | { |
| 71 | struct stat st; |
| 72 | if (stat (file1, &st) == 0 && S_ISDIR (st.st_mode)) |
| 73 | errno = EPERM; |
| 74 | else |
| 75 | errno = ENOTDIR; |
| 76 | return -1; |
| 77 | } |
| 78 | /* CreateHardLink("b/.","a",NULL) creates file "b", so we must check |
| 79 | that dirname(file2) exists. */ |
| 80 | dir = strdup (file2); |
| 81 | if (!dir) |
| 82 | return -1; |
| 83 | { |
| 84 | struct stat st; |
| 85 | char *p = strchr (dir, '\0'); |
| 86 | while (dir < p && (*--p != '/' && *p != '\\')); |
| 87 | *p = '\0'; |
| 88 | if (p != dir && stat (dir, &st) == -1) |
| 89 | { |
| 90 | int saved_errno = errno; |
| 91 | free (dir); |
| 92 | errno = saved_errno; |
| 93 | return -1; |
| 94 | } |
| 95 | free (dir); |
| 96 | } |
| 97 | /* Now create the link. */ |
| 98 | if (CreateHardLinkFunc (file2, file1, NULL) == 0) |
| 99 | { |
| 100 | /* It is not documented which errors CreateHardLink() can produce. |
| 101 | * The following conversions are based on tests on a Windows XP SP2 |
| 102 | * system. */ |
| 103 | DWORD err = GetLastError (); |
| 104 | switch (err) |
| 105 | { |
| 106 | case ERROR_ACCESS_DENIED: |
| 107 | errno = EACCES; |
| 108 | break; |
| 109 | |
| 110 | case ERROR_INVALID_FUNCTION: /* fs does not support hard links */ |
| 111 | errno = EPERM; |
| 112 | break; |
| 113 | |
| 114 | case ERROR_NOT_SAME_DEVICE: |
| 115 | errno = EXDEV; |
| 116 | break; |
| 117 | |
| 118 | case ERROR_PATH_NOT_FOUND: |
| 119 | case ERROR_FILE_NOT_FOUND: |
| 120 | errno = ENOENT; |
| 121 | break; |
| 122 | |
| 123 | case ERROR_INVALID_PARAMETER: |
| 124 | errno = ENAMETOOLONG; |
| 125 | break; |
| 126 | |
| 127 | case ERROR_TOO_MANY_LINKS: |
| 128 | errno = EMLINK; |
| 129 | break; |
| 130 | |
| 131 | case ERROR_ALREADY_EXISTS: |
| 132 | errno = EEXIST; |
| 133 | break; |
| 134 | |
| 135 | default: |
| 136 | errno = EIO; |
| 137 | } |
| 138 | return -1; |
| 139 | } |
| 140 | |
| 141 | return 0; |
| 142 | } |
| 143 | |
| 144 | # else /* !Windows */ |
| 145 | |
| 146 | # error "This platform lacks a link function, and Gnulib doesn't provide a replacement. This is a bug in Gnulib." |
| 147 | |
| 148 | # endif /* !Windows */ |
| 149 | #else /* HAVE_LINK */ |
| 150 | |
| 151 | # undef link |
| 152 | |
| 153 | /* Create a hard link from FILE1 to FILE2, working around platform bugs. */ |
| 154 | int |
| 155 | rpl_link (char const *file1, char const *file2) |
| 156 | { |
| 157 | size_t len1; |
| 158 | size_t len2; |
| 159 | struct stat st; |
| 160 | |
| 161 | /* Don't allow IRIX to dereference dangling file2 symlink. */ |
| 162 | if (!lstat (file2, &st)) |
| 163 | { |
| 164 | errno = EEXIST; |
| 165 | return -1; |
| 166 | } |
| 167 | |
| 168 | /* Reject trailing slashes on non-directories. */ |
| 169 | len1 = strlen (file1); |
| 170 | len2 = strlen (file2); |
| 171 | if ((len1 && file1[len1 - 1] == '/') |
| 172 | || (len2 && file2[len2 - 1] == '/')) |
| 173 | { |
| 174 | /* Let link() decide whether hard-linking directories is legal. |
| 175 | If stat() fails, then link() should fail for the same reason |
| 176 | (although on Solaris 9, link("file/","oops") mistakenly |
| 177 | succeeds); if stat() succeeds, require a directory. */ |
| 178 | if (stat (file1, &st)) |
| 179 | return -1; |
| 180 | if (!S_ISDIR (st.st_mode)) |
| 181 | { |
| 182 | errno = ENOTDIR; |
| 183 | return -1; |
| 184 | } |
| 185 | } |
| 186 | else |
| 187 | { |
| 188 | /* Fix Cygwin 1.5.x bug where link("a","b/.") creates file "b". */ |
| 189 | char *dir = strdup (file2); |
| 190 | char *p; |
| 191 | if (!dir) |
| 192 | return -1; |
| 193 | /* We already know file2 does not end in slash. Strip off the |
| 194 | basename, then check that the dirname exists. */ |
| 195 | p = strrchr (dir, '/'); |
| 196 | if (p) |
| 197 | { |
| 198 | *p = '\0'; |
| 199 | if (stat (dir, &st) == -1) |
| 200 | { |
| 201 | int saved_errno = errno; |
| 202 | free (dir); |
| 203 | errno = saved_errno; |
| 204 | return -1; |
| 205 | } |
| 206 | } |
| 207 | free (dir); |
| 208 | } |
| 209 | return link (file1, file2); |
| 210 | } |
| 211 | #endif /* HAVE_LINK */ |