| /* Work around unlinkat bugs on Solaris 9 and Hurd. |
| |
| Copyright (C) 2009-2020 Free Software Foundation, Inc. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| /* Written by Eric Blake. */ |
| |
| #include <config.h> |
| |
| #include <unistd.h> |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <string.h> |
| #include <sys/stat.h> |
| |
| #include <stdlib.h> |
| |
| #include "filename.h" |
| #include "openat.h" |
| |
| #if HAVE_UNLINKAT |
| |
| # undef unlinkat |
| |
| /* unlinkat without AT_REMOVEDIR does not honor trailing / on Solaris 9. |
| Hurd has the same issue. |
| |
| unlinkat without AT_REMOVEDIR erroneously ignores ".." on Darwin 14. |
| |
| Solve these in a similar manner to unlink. */ |
| |
| int |
| rpl_unlinkat (int fd, char const *name, int flag) |
| { |
| size_t len; |
| int result = 0; |
| /* rmdir behavior has no problems with trailing slash. */ |
| if (flag & AT_REMOVEDIR) |
| return unlinkat (fd, name, flag); |
| |
| len = strlen (name); |
| if (len && ISSLASH (name[len - 1])) |
| { |
| /* See the lengthy comment in unlink.c why we disobey the POSIX |
| rule of letting unlink("link-to-dir/") attempt to unlink a |
| directory. */ |
| struct stat st; |
| result = lstatat (fd, name, &st); |
| if (result == 0) |
| { |
| /* Trailing NUL will overwrite the trailing slash. */ |
| char *short_name = malloc (len); |
| if (!short_name) |
| { |
| errno = EPERM; |
| return -1; |
| } |
| memcpy (short_name, name, len); |
| while (len && ISSLASH (short_name[len - 1])) |
| short_name[--len] = '\0'; |
| if (len && (lstatat (fd, short_name, &st) || S_ISLNK (st.st_mode))) |
| { |
| free (short_name); |
| errno = EPERM; |
| return -1; |
| } |
| free (short_name); |
| } |
| } |
| if (!result) |
| { |
| # if UNLINK_PARENT_BUG |
| if (len >= 2 && name[len - 1] == '.' && name[len - 2] == '.' |
| && (len == 2 || ISSLASH (name[len - 3]))) |
| { |
| errno = EISDIR; /* could also use EPERM */ |
| return -1; |
| } |
| # endif |
| result = unlinkat (fd, name, flag); |
| } |
| return result; |
| } |
| |
| #else /* !HAVE_UNLINKAT */ |
| |
| /* Replacement for Solaris' function by the same name. |
| <https://www.google.com/search?q=unlinkat+site:docs.oracle.com> |
| First, try to simulate it via (unlink|rmdir) ("/proc/self/fd/FD/FILE"). |
| Failing that, simulate it via save_cwd/fchdir/(unlink|rmdir)/restore_cwd. |
| If either the save_cwd or the restore_cwd fails (relatively unlikely), |
| then give a diagnostic and exit nonzero. |
| Otherwise, this function works just like Solaris' unlinkat. */ |
| |
| # define AT_FUNC_NAME unlinkat |
| # define AT_FUNC_F1 rmdir |
| # define AT_FUNC_F2 unlink |
| # define AT_FUNC_USE_F1_COND AT_REMOVEDIR |
| # define AT_FUNC_POST_FILE_PARAM_DECLS , int flag |
| # define AT_FUNC_POST_FILE_ARGS /* empty */ |
| # include "at-func.c" |
| # undef AT_FUNC_NAME |
| # undef AT_FUNC_F1 |
| # undef AT_FUNC_F2 |
| # undef AT_FUNC_USE_F1_COND |
| # undef AT_FUNC_POST_FILE_PARAM_DECLS |
| # undef AT_FUNC_POST_FILE_ARGS |
| |
| #endif /* !HAVE_UNLINKAT */ |