2 Copyright (C) 2006-2009 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
29 #include <sys/types.h>
32 #ifndef REPLACE_OPEN_DIRECTORY
33 # define REPLACE_OPEN_DIRECTORY 0
36 #ifndef HAVE_CANONICALIZE_FILE_NAME
37 # if GNULIB_CANONICALIZE || GNULIB_CANONICALIZE_LGPL
38 # define HAVE_CANONICALIZE_FILE_NAME 1
40 # define HAVE_CANONICALIZE_FILE_NAME 0
44 /* This replacement assumes that a directory is not renamed while opened
45 through a file descriptor.
47 FIXME: On mingw, this would be possible to enforce if we were to
48 also open a HANDLE to each directory currently visited by a file
49 descriptor, since mingw refuses to rename any in-use file system
52 /* Array of file descriptors opened. If it points to a directory, it stores
53 info about this directory. */
56 char *name; /* Absolute name of the directory, or NULL. */
57 /* FIXME - add a DIR* member to make dirfd possible on mingw? */
59 static dir_info_t *dirs;
60 static size_t dirs_allocated;
62 /* Try to ensure dirs has enough room for a slot at index fd. Return
63 false and set errno to ENOMEM on allocation failure. */
65 ensure_dirs_slot (size_t fd)
67 if (fd >= dirs_allocated)
72 new_allocated = 2 * dirs_allocated + 1;
73 if (new_allocated <= fd)
74 new_allocated = fd + 1;
77 ? (dir_info_t *) realloc (dirs, new_allocated * sizeof *dirs)
78 : (dir_info_t *) malloc (new_allocated * sizeof *dirs));
81 memset (new_dirs + dirs_allocated, 0,
82 (new_allocated - dirs_allocated) * sizeof *dirs);
84 dirs_allocated = new_allocated;
89 /* Return the canonical name of DIR in malloc'd storage. */
91 get_name (char const *dir)
94 if (REPLACE_OPEN_DIRECTORY || !HAVE_CANONICALIZE_FILE_NAME)
96 /* The function canonicalize_file_name has not yet been ported
97 to mingw, with all its drive letter and backslash quirks.
98 Fortunately, getcwd is reliable in this case, but we ensure
99 we can get back to where we started before using it. Treat
100 "." as a special case, as it is frequently encountered. */
101 char *cwd = getcwd (NULL, 0);
103 if (dir[0] == '.' && dir[1] == '\0')
107 result = chdir (dir) ? NULL : getcwd (NULL, 0);
115 /* Avoid changing the directory. */
116 result = canonicalize_file_name (dir);
121 /* Hook into the gnulib replacements for open() and close() to keep track
122 of the open file descriptors. */
124 /* Close FD, cleaning up any fd to name mapping if fd was visiting a
127 _gl_unregister_fd (int fd)
129 if (fd >= 0 && fd < dirs_allocated)
131 free (dirs[fd].name);
132 dirs[fd].name = NULL;
136 /* Mark FD as visiting FILENAME. FD must be non-negative, and refer
137 to an open file descriptor. If REPLACE_OPEN_DIRECTORY is non-zero,
138 this should only be called if FD is visiting a directory. Close FD
139 and return -1 if there is insufficient memory to track the
140 directory name; otherwise return FD. */
142 _gl_register_fd (int fd, const char *filename)
147 if (REPLACE_OPEN_DIRECTORY
148 || (fstat (fd, &statbuf) == 0 && S_ISDIR (statbuf.st_mode)))
150 if (!ensure_dirs_slot (fd)
151 || (dirs[fd].name = get_name (filename)) == NULL)
153 int saved_errno = errno;
162 /* Mark NEWFD as a duplicate of OLDFD; useful from dup, dup2, dup3,
163 and fcntl. Both arguments must be valid and distinct file
164 descriptors. Close NEWFD and return -1 if OLDFD is tracking a
165 directory, but there is insufficient memory to track the same
166 directory in NEWFD; otherwise return NEWFD.
168 FIXME: Need to implement rpl_fcntl in gnulib, and have it call
171 _gl_register_dup (int oldfd, int newfd)
173 assert (0 <= oldfd && 0 <= newfd && oldfd != newfd);
174 if (oldfd < dirs_allocated && dirs[oldfd].name)
176 /* Duplicated a directory; must ensure newfd is allocated. */
177 if (!ensure_dirs_slot (newfd)
178 || (dirs[newfd].name = strdup (dirs[oldfd].name)) == NULL)
180 int saved_errno = errno;
186 else if (newfd < dirs_allocated)
188 /* Duplicated a non-directory; ensure newfd is cleared. */
189 free (dirs[newfd].name);
190 dirs[newfd].name = NULL;
195 /* If FD is currently visiting a directory, then return the name of
196 that directory. Otherwise, return NULL and set errno. */
198 _gl_directory_name (int fd)
200 if (0 <= fd && fd < dirs_allocated && dirs[fd].name != NULL)
201 return dirs[fd].name;
202 /* At this point, fd is either invalid, or open but not a directory.
203 If dup2 fails, errno is correctly EBADF. */
206 if (dup2 (fd, fd) == fd)
214 /* Return stat information about FD in STATBUF. Needed when
215 rpl_open() used a dummy file to work around an open() that can't
216 normally visit directories. */
217 #if REPLACE_OPEN_DIRECTORY
219 rpl_fstat (int fd, struct stat *statbuf)
221 if (0 <= fd && fd < dirs_allocated && dirs[fd].name != NULL)
222 return stat (dirs[fd].name, statbuf);
223 return fstat (fd, statbuf);
227 /* Override opendir() and closedir(), to keep track of the open file
228 descriptors. Needed because there is a function dirfd(). */
231 rpl_closedir (DIR *dp)
235 int retval = closedir (dp);
238 _gl_unregister_fd (fd);
243 rpl_opendir (const char *filename)
248 dp = opendir (filename);
252 if (0 <= fd && _gl_register_fd (fd, filename) != fd)
254 int saved_errno = errno;
263 /* Override dup(), to keep track of open file descriptors. */
269 int newfd = dup (oldfd);
272 newfd = _gl_register_dup (oldfd, newfd);
277 /* Implement fchdir() in terms of chdir(). */
282 const char *name = _gl_directory_name (fd);
283 return name ? chdir (name) : -1;