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 /* This replacement assumes that a directory is not renamed while opened
37 through a file descriptor.
39 FIXME: On mingw, this would be possible to enforce if we were to
40 also open a HANDLE to each directory currently visited by a file
41 descriptor, since mingw refuses to rename any in-use file system
44 /* Array of file descriptors opened. If it points to a directory, it stores
45 info about this directory. */
48 char *name; /* Absolute name of the directory, or NULL. */
49 /* FIXME - add a DIR* member to make dirfd possible on mingw? */
51 static dir_info_t *dirs;
52 static size_t dirs_allocated;
54 /* Try to ensure dirs has enough room for a slot at index fd. Return
55 false and set errno to ENOMEM on allocation failure. */
57 ensure_dirs_slot (size_t fd)
59 if (fd >= dirs_allocated)
64 new_allocated = 2 * dirs_allocated + 1;
65 if (new_allocated <= fd)
66 new_allocated = fd + 1;
69 ? (dir_info_t *) realloc (dirs, new_allocated * sizeof *dirs)
70 : (dir_info_t *) malloc (new_allocated * sizeof *dirs));
73 memset (new_dirs + dirs_allocated, 0,
74 (new_allocated - dirs_allocated) * sizeof *dirs);
76 dirs_allocated = new_allocated;
81 /* Hook into the gnulib replacements for open() and close() to keep track
82 of the open file descriptors. */
84 /* Close FD, cleaning up any fd to name mapping if fd was visiting a
87 _gl_unregister_fd (int fd)
89 if (fd >= 0 && fd < dirs_allocated)
96 /* Mark FD as visiting FILENAME. FD must be non-negative, and refer
97 to an open file descriptor. If REPLACE_OPEN_DIRECTORY is non-zero,
98 this should only be called if FD is visiting a directory. Close FD
99 and return -1 if there is insufficient memory to track the
100 directory name; otherwise return FD. */
102 _gl_register_fd (int fd, const char *filename)
107 if (REPLACE_OPEN_DIRECTORY
108 || (fstat (fd, &statbuf) == 0 && S_ISDIR (statbuf.st_mode)))
110 if (!ensure_dirs_slot (fd)
111 || (dirs[fd].name = canonicalize_file_name (filename)) == NULL)
113 int saved_errno = errno;
122 /* Mark NEWFD as a duplicate of OLDFD; useful from dup, dup2, dup3,
123 and fcntl. Both arguments must be valid and distinct file
124 descriptors. Close NEWFD and return -1 if OLDFD is tracking a
125 directory, but there is insufficient memory to track the same
126 directory in NEWFD; otherwise return NEWFD.
128 FIXME: Need to implement rpl_fcntl in gnulib, and have it call
131 _gl_register_dup (int oldfd, int newfd)
133 assert (0 <= oldfd && 0 <= newfd && oldfd != newfd);
134 if (oldfd < dirs_allocated && dirs[oldfd].name)
136 /* Duplicated a directory; must ensure newfd is allocated. */
137 if (!ensure_dirs_slot (newfd)
138 || (dirs[newfd].name = strdup (dirs[oldfd].name)) == NULL)
140 int saved_errno = errno;
146 else if (newfd < dirs_allocated)
148 /* Duplicated a non-directory; ensure newfd is cleared. */
149 free (dirs[newfd].name);
150 dirs[newfd].name = NULL;
155 /* If FD is currently visiting a directory, then return the name of
156 that directory. Otherwise, return NULL and set errno. */
158 _gl_directory_name (int fd)
160 if (0 <= fd && fd < dirs_allocated && dirs[fd].name != NULL)
161 return dirs[fd].name;
162 /* At this point, fd is either invalid, or open but not a directory.
163 If dup2 fails, errno is correctly EBADF. */
166 if (dup2 (fd, fd) == fd)
174 /* Return stat information about FD in STATBUF. Needed when
175 rpl_open() used a dummy file to work around an open() that can't
176 normally visit directories. */
177 #if REPLACE_OPEN_DIRECTORY
179 rpl_fstat (int fd, struct stat *statbuf)
181 if (0 <= fd && fd < dirs_allocated && dirs[fd].name != NULL)
182 return stat (dirs[fd].name, statbuf);
183 return fstat (fd, statbuf);
187 /* Override opendir() and closedir(), to keep track of the open file
188 descriptors. Needed because there is a function dirfd(). */
191 rpl_closedir (DIR *dp)
195 int retval = closedir (dp);
198 _gl_unregister_fd (fd);
203 rpl_opendir (const char *filename)
208 dp = opendir (filename);
212 if (0 <= fd && _gl_register_fd (fd, filename) != fd)
214 int saved_errno = errno;
223 /* Override dup(), to keep track of open file descriptors. */
229 int newfd = dup (oldfd);
232 newfd = _gl_register_dup (oldfd, newfd);
237 /* Implement fchdir() in terms of chdir(). */
242 const char *name = _gl_directory_name (fd);
243 return name ? chdir (name) : -1;