2 Copyright (C) 2006-2015 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/>. */
28 #include <sys/types.h>
33 #include "filenamecat.h"
35 #ifndef REPLACE_OPEN_DIRECTORY
36 # define REPLACE_OPEN_DIRECTORY 0
39 /* This replacement assumes that a directory is not renamed while opened
40 through a file descriptor.
42 FIXME: On mingw, this would be possible to enforce if we were to
43 also open a HANDLE to each directory currently visited by a file
44 descriptor, since mingw refuses to rename any in-use file system
47 /* Array of file descriptors opened. If REPLACE_OPEN_DIRECTORY or if it points
48 to a directory, it stores info about this directory. */
51 char *name
; /* Absolute name of the directory, or NULL. */
52 /* FIXME - add a DIR* member to make dirfd possible on mingw? */
54 static dir_info_t
*dirs
;
55 static size_t dirs_allocated
;
57 /* Try to ensure dirs has enough room for a slot at index fd; free any
58 contents already in that slot. Return false and set errno to
59 ENOMEM on allocation failure. */
61 ensure_dirs_slot (size_t fd
)
63 if (fd
< dirs_allocated
)
70 new_allocated
= 2 * dirs_allocated
+ 1;
71 if (new_allocated
<= fd
)
72 new_allocated
= fd
+ 1;
75 ? (dir_info_t
*) realloc (dirs
, new_allocated
* sizeof *dirs
)
76 : (dir_info_t
*) malloc (new_allocated
* sizeof *dirs
));
79 memset (new_dirs
+ dirs_allocated
, 0,
80 (new_allocated
- dirs_allocated
) * sizeof *dirs
);
82 dirs_allocated
= new_allocated
;
87 /* Return an absolute name of DIR in malloc'd storage. */
89 get_name (char const *dir
)
95 if (IS_ABSOLUTE_FILE_NAME (dir
))
98 /* We often encounter "."; treat it as a special case. */
99 cwd
= getcwd (NULL
, 0);
100 if (!cwd
|| (dir
[0] == '.' && dir
[1] == '\0'))
103 result
= mfile_name_concat (cwd
, dir
, NULL
);
110 /* Hook into the gnulib replacements for open() and close() to keep track
111 of the open file descriptors. */
113 /* Close FD, cleaning up any fd to name mapping if fd was visiting a
116 _gl_unregister_fd (int fd
)
118 if (fd
>= 0 && fd
< dirs_allocated
)
120 free (dirs
[fd
].name
);
121 dirs
[fd
].name
= NULL
;
125 /* Mark FD as visiting FILENAME. FD must be non-negative, and refer
126 to an open file descriptor. If REPLACE_OPEN_DIRECTORY is non-zero,
127 this should only be called if FD is visiting a directory. Close FD
128 and return -1 if there is insufficient memory to track the
129 directory name; otherwise return FD. */
131 _gl_register_fd (int fd
, const char *filename
)
136 if (REPLACE_OPEN_DIRECTORY
137 || (fstat (fd
, &statbuf
) == 0 && S_ISDIR (statbuf
.st_mode
)))
139 if (!ensure_dirs_slot (fd
)
140 || (dirs
[fd
].name
= get_name (filename
)) == NULL
)
142 int saved_errno
= errno
;
151 /* Mark NEWFD as a duplicate of OLDFD; useful from dup, dup2, dup3,
152 and fcntl. Both arguments must be valid and distinct file
153 descriptors. Close NEWFD and return -1 if OLDFD is tracking a
154 directory, but there is insufficient memory to track the same
155 directory in NEWFD; otherwise return NEWFD. */
157 _gl_register_dup (int oldfd
, int newfd
)
159 assure (0 <= oldfd
&& 0 <= newfd
&& oldfd
!= newfd
);
160 if (oldfd
< dirs_allocated
&& dirs
[oldfd
].name
)
162 /* Duplicated a directory; must ensure newfd is allocated. */
163 if (!ensure_dirs_slot (newfd
)
164 || (dirs
[newfd
].name
= strdup (dirs
[oldfd
].name
)) == NULL
)
166 int saved_errno
= errno
;
172 else if (newfd
< dirs_allocated
)
174 /* Duplicated a non-directory; ensure newfd is cleared. */
175 free (dirs
[newfd
].name
);
176 dirs
[newfd
].name
= NULL
;
181 /* If FD is currently visiting a directory, then return the name of
182 that directory. Otherwise, return NULL and set errno. */
184 _gl_directory_name (int fd
)
186 if (0 <= fd
&& fd
< dirs_allocated
&& dirs
[fd
].name
!= NULL
)
187 return dirs
[fd
].name
;
188 /* At this point, fd is either invalid, or open but not a directory.
189 If dup2 fails, errno is correctly EBADF. */
192 if (dup2 (fd
, fd
) == fd
)
201 /* Implement fchdir() in terms of chdir(). */
206 const char *name
= _gl_directory_name (fd
);
207 return name
? chdir (name
) : -1;