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 #include "canonicalize.h"
34 #ifndef REPLACE_OPEN_DIRECTORY
35 # define REPLACE_OPEN_DIRECTORY 0
38 /* This replacement assumes that a directory is not renamed while opened
39 through a file descriptor.
41 FIXME: On mingw, this would be possible to enforce if we were to
42 also open a HANDLE to each directory currently visited by a file
43 descriptor, since mingw refuses to rename any in-use file system
46 /* Array of file descriptors opened. If it points to a directory, it stores
47 info about this directory. */
50 char *name; /* Absolute name of the directory, or NULL. */
51 /* FIXME - add a DIR* member to make dirfd possible on mingw? */
53 static dir_info_t *dirs;
54 static size_t dirs_allocated;
56 /* Try to ensure dirs has enough room for a slot at index fd. Return
57 false and set errno to ENOMEM on allocation failure. */
59 ensure_dirs_slot (size_t fd)
61 if (fd >= dirs_allocated)
66 new_allocated = 2 * dirs_allocated + 1;
67 if (new_allocated <= fd)
68 new_allocated = fd + 1;
71 ? (dir_info_t *) realloc (dirs, new_allocated * sizeof *dirs)
72 : (dir_info_t *) malloc (new_allocated * sizeof *dirs));
75 memset (new_dirs + dirs_allocated, 0,
76 (new_allocated - dirs_allocated) * sizeof *dirs);
78 dirs_allocated = new_allocated;
83 /* Hook into the gnulib replacements for open() and close() to keep track
84 of the open file descriptors. */
86 /* Close FD, cleaning up any fd to name mapping if fd was visiting a
89 _gl_unregister_fd (int fd)
91 if (fd >= 0 && fd < dirs_allocated)
98 /* Mark FD as visiting FILENAME. FD must be non-negative, and refer
99 to an open file descriptor. If REPLACE_OPEN_DIRECTORY is non-zero,
100 this should only be called if FD is visiting a directory. Close FD
101 and return -1 if there is insufficient memory to track the
102 directory name; otherwise return FD. */
104 _gl_register_fd (int fd, const char *filename)
109 if (REPLACE_OPEN_DIRECTORY
110 || (fstat (fd, &statbuf) == 0 && S_ISDIR (statbuf.st_mode)))
112 if (!ensure_dirs_slot (fd)
113 || (dirs[fd].name = canonicalize_file_name (filename)) == NULL)
115 int saved_errno = errno;
124 /* Mark NEWFD as a duplicate of OLDFD; useful from dup, dup2, dup3,
125 and fcntl. Both arguments must be valid and distinct file
126 descriptors. Close NEWFD and return -1 if OLDFD is tracking a
127 directory, but there is insufficient memory to track the same
128 directory in NEWFD; otherwise return NEWFD.
130 FIXME: Need to implement rpl_fcntl in gnulib, and have it call
133 _gl_register_dup (int oldfd, int newfd)
135 assert (0 <= oldfd && 0 <= newfd && oldfd != newfd);
136 if (oldfd < dirs_allocated && dirs[oldfd].name)
138 /* Duplicated a directory; must ensure newfd is allocated. */
139 if (!ensure_dirs_slot (newfd)
140 || (dirs[newfd].name = strdup (dirs[oldfd].name)) == NULL)
142 int saved_errno = errno;
148 else if (newfd < dirs_allocated)
150 /* Duplicated a non-directory; ensure newfd is cleared. */
151 free (dirs[newfd].name);
152 dirs[newfd].name = NULL;
157 /* If FD is currently visiting a directory, then return the name of
158 that directory. Otherwise, return NULL and set errno. */
160 _gl_directory_name (int fd)
162 if (0 <= fd && fd < dirs_allocated && dirs[fd].name != NULL)
163 return dirs[fd].name;
164 /* At this point, fd is either invalid, or open but not a directory.
165 If dup2 fails, errno is correctly EBADF. */
168 if (dup2 (fd, fd) == fd)
176 /* Return stat information about FD in STATBUF. Needed when
177 rpl_open() used a dummy file to work around an open() that can't
178 normally visit directories. */
179 #if REPLACE_OPEN_DIRECTORY
181 rpl_fstat (int fd, struct stat *statbuf)
183 if (0 <= fd && fd < dirs_allocated && dirs[fd].name != NULL)
184 return stat (dirs[fd].name, statbuf);
185 return fstat (fd, statbuf);
189 /* Override opendir() and closedir(), to keep track of the open file
190 descriptors. Needed because there is a function dirfd(). */
193 rpl_closedir (DIR *dp)
197 int retval = closedir (dp);
200 _gl_unregister_fd (fd);
205 rpl_opendir (const char *filename)
210 dp = opendir (filename);
214 if (0 <= fd && _gl_register_fd (fd, filename) != fd)
216 int saved_errno = errno;
225 /* Override dup(), to keep track of open file descriptors. */
231 int newfd = dup (oldfd);
234 newfd = _gl_register_dup (oldfd, newfd);
239 /* Implement fchdir() in terms of chdir(). */
244 const char *name = _gl_directory_name (fd);
245 return name ? chdir (name) : -1;