1 /* Temporary directories and temporary files with automatic cleanup.
2 Copyright (C) 2001, 2003, 2006-2007 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2006.
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
23 #include "clean-temp.h"
33 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
34 # define WIN32_LEAN_AND_MEAN /* avoid including junk */
39 #include "fatal-signal.h"
45 #include "gl_linkedhash_list.h"
47 #if GNULIB_FWRITEERROR
48 # include "fwriteerror.h"
50 #if GNULIB_CLOSE_STREAM
51 # include "close-stream.h"
53 #if GNULIB_FCNTL_SAFER
56 #if GNULIB_FOPEN_SAFER
60 #define _(str) gettext (str)
62 /* GNU Hurd doesn't have PATH_MAX. */
65 # define PATH_MAX MAXPATHLEN
67 # define PATH_MAX 1024
72 # define uintptr_t unsigned long
75 #if !GNULIB_FCNTL_SAFER
76 /* The results of open() in this file are not used with fchdir,
77 therefore save some unnecessary work in fchdir.c. */
83 /* The use of 'volatile' in the types below (and ISO C 99 section 5.1.2.3.(5))
84 ensure that while constructing or modifying the data structures, the field
85 values are written to memory in the order of the C statements. So the
86 signal handler can rely on these field values to be up to date. */
89 /* Registry for a single temporary directory.
90 'struct temp_dir' from the public header file overlaps with this. */
93 /* The absolute pathname of the directory. */
94 char * volatile dirname;
95 /* Whether errors during explicit cleanup are reported to standard error. */
97 /* Absolute pathnames of subdirectories. */
98 gl_list_t /* <char *> */ volatile subdirs;
99 /* Absolute pathnames of files. */
100 gl_list_t /* <char *> */ volatile files;
103 /* List of all temporary directories. */
106 struct tempdir * volatile * volatile tempdir_list;
107 size_t volatile tempdir_count;
108 size_t tempdir_allocated;
109 } cleanup_list /* = { NULL, 0, 0 } */;
111 /* List of all open file descriptors to temporary files. */
112 static gl_list_t /* <int> */ volatile descriptors;
115 /* For the subdirs and for the files, we use a gl_list_t of type LINKEDHASH.
116 Why? We need a data structure that
118 1) Can contain an arbitrary number of 'char *' values. The strings
119 are compared via strcmp, not pointer comparison.
120 2) Has insertion and deletion operations that are fast: ideally O(1),
121 or possibly O(log n). This is important for GNU sort, which may
122 create a large number of temporary files.
123 3) Allows iteration through all elements from within a signal handler.
124 4) May or may not allow duplicates. It doesn't matter here, since
125 any file or subdir can only be removed once.
127 Criterion 1) would allow any gl_list_t or gl_oset_t implementation.
129 Criterion 2) leaves only GL_LINKEDHASH_LIST, GL_TREEHASH_LIST, or
132 Criterion 3) puts at disadvantage GL_TREEHASH_LIST and GL_TREE_OSET.
133 Namely, iteration through the elements of a binary tree requires access
134 to many ->left, ->right, ->parent pointers. However, the rebalancing
135 code for insertion and deletion in an AVL or red-black tree is so
136 complicated that we cannot assume that >left, ->right, ->parent pointers
137 are in a consistent state throughout these operations. Therefore, to
138 avoid a crash in the signal handler, all destructive operations to the
139 lists would have to be protected by a
140 block_fatal_signals ();
142 unblock_fatal_signals ();
143 pair. Which causes extra system calls.
145 Criterion 3) would also discourage GL_ARRAY_LIST and GL_CARRAY_LIST,
146 if they were not already excluded. Namely, these implementations use
147 xrealloc(), leaving a time window in which in the list->elements pointer
148 points to already deallocated memory. To avoid a crash in the signal
149 handler at such a moment, all destructive operations would have to
150 protected by block/unblock_fatal_signals (), in this case too.
152 A list of type GL_LINKEDHASH_LIST without duplicates fulfills all
154 2) Insertion and deletion are O(1) on average.
155 3) The gl_list_iterator, gl_list_iterator_next implementations do
156 not trigger memory allocations, nor other system calls, and are
157 therefore safe to be called from a signal handler.
158 Furthermore, since SIGNAL_SAFE_LIST is defined, the implementation
159 of the destructive functions ensures that the list structure is
160 safe to be traversed at any moment, even when interrupted by an
164 /* String equality and hash code functions used by the lists. */
167 string_equals (const void *x1, const void *x2)
169 const char *s1 = (const char *) x1;
170 const char *s2 = (const char *) x2;
171 return strcmp (s1, s2) == 0;
174 #define SIZE_BITS (sizeof (size_t) * CHAR_BIT)
176 /* A hash function for NUL-terminated char* strings using
177 the method described by Bruno Haible.
178 See http://www.haible.de/bruno/hashfunc.html. */
180 string_hash (const void *x)
182 const char *s = (const char *) x;
186 h = *s + ((h << 9) | (h >> (SIZE_BITS - 9)));
192 /* The signal handler. It gets called asynchronously. */
198 /* First close all file descriptors to temporary files. */
200 gl_list_t fds = descriptors;
204 gl_list_iterator_t iter;
207 iter = gl_list_iterator (fds);
208 while (gl_list_iterator_next (&iter, &element, NULL))
210 int fd = (int) (uintptr_t) element;
213 gl_list_iterator_free (&iter);
217 for (i = 0; i < cleanup_list.tempdir_count; i++)
219 struct tempdir *dir = cleanup_list.tempdir_list[i];
223 gl_list_iterator_t iter;
226 /* First cleanup the files in the subdirectories. */
227 iter = gl_list_iterator (dir->files);
228 while (gl_list_iterator_next (&iter, &element, NULL))
230 const char *file = (const char *) element;
233 gl_list_iterator_free (&iter);
235 /* Then cleanup the subdirectories. */
236 iter = gl_list_iterator (dir->subdirs);
237 while (gl_list_iterator_next (&iter, &element, NULL))
239 const char *subdir = (const char *) element;
242 gl_list_iterator_free (&iter);
244 /* Then cleanup the temporary directory itself. */
245 rmdir (dir->dirname);
250 /* Create a temporary directory.
251 PREFIX is used as a prefix for the name of the temporary directory. It
252 should be short and still give an indication about the program.
253 PARENTDIR can be used to specify the parent directory; if NULL, a default
254 parent directory is used (either $TMPDIR or /tmp or similar).
255 CLEANUP_VERBOSE determines whether errors during explicit cleanup are
256 reported to standard error.
257 Return a fresh 'struct temp_dir' on success. Upon error, an error message
258 is shown and NULL is returned. */
260 create_temp_dir (const char *prefix, const char *parentdir,
261 bool cleanup_verbose)
263 struct tempdir * volatile *tmpdirp = NULL;
264 struct tempdir *tmpdir;
269 /* See whether it can take the slot of an earlier temporary directory
270 already cleaned up. */
271 for (i = 0; i < cleanup_list.tempdir_count; i++)
272 if (cleanup_list.tempdir_list[i] == NULL)
274 tmpdirp = &cleanup_list.tempdir_list[i];
279 /* See whether the array needs to be extended. */
280 if (cleanup_list.tempdir_count == cleanup_list.tempdir_allocated)
282 /* Note that we cannot use xrealloc(), because then the cleanup()
283 function could access an already deallocated array. */
284 struct tempdir * volatile *old_array = cleanup_list.tempdir_list;
285 size_t old_allocated = cleanup_list.tempdir_allocated;
286 size_t new_allocated = 2 * cleanup_list.tempdir_allocated + 1;
287 struct tempdir * volatile *new_array =
288 XNMALLOC (new_allocated, struct tempdir * volatile);
290 if (old_allocated == 0)
291 /* First use of this facility. Register the cleanup handler. */
292 at_fatal_signal (&cleanup);
295 /* Don't use memcpy() here, because memcpy takes non-volatile
296 arguments and is therefore not guaranteed to complete all
297 memory stores before the next statement. */
300 for (k = 0; k < old_allocated; k++)
301 new_array[k] = old_array[k];
304 cleanup_list.tempdir_list = new_array;
305 cleanup_list.tempdir_allocated = new_allocated;
307 /* Now we can free the old array. */
308 if (old_array != NULL)
309 free ((struct tempdir **) old_array);
312 tmpdirp = &cleanup_list.tempdir_list[cleanup_list.tempdir_count];
313 /* Initialize *tmpdirp before incrementing tempdir_count, so that
314 cleanup() will skip this entry before it is fully initialized. */
316 cleanup_list.tempdir_count++;
319 /* Initialize a 'struct tempdir'. */
320 tmpdir = XMALLOC (struct tempdir);
321 tmpdir->dirname = NULL;
322 tmpdir->cleanup_verbose = cleanup_verbose;
323 tmpdir->subdirs = gl_list_create_empty (GL_LINKEDHASH_LIST,
324 string_equals, string_hash, false);
325 tmpdir->files = gl_list_create_empty (GL_LINKEDHASH_LIST,
326 string_equals, string_hash, false);
328 /* Create the temporary directory. */
329 xtemplate = (char *) xallocsa (PATH_MAX);
330 if (path_search (xtemplate, PATH_MAX, parentdir, prefix, parentdir == NULL))
333 _("cannot find a temporary directory, try setting $TMPDIR"));
336 block_fatal_signals ();
337 tmpdirname = mkdtemp (xtemplate);
338 if (tmpdirname != NULL)
340 tmpdir->dirname = tmpdirname;
343 unblock_fatal_signals ();
344 if (tmpdirname == NULL)
347 _("cannot create a temporary directory using template \"%s\""),
351 /* Replace tmpdir->dirname with a copy that has indefinite extent.
352 We cannot do this inside the block_fatal_signals/unblock_fatal_signals
353 block because then the cleanup handler would not remove the directory
355 tmpdir->dirname = xstrdup (tmpdirname);
357 return (struct temp_dir *) tmpdir;
364 /* Register the given ABSOLUTE_FILE_NAME as being a file inside DIR, that
365 needs to be removed before DIR can be removed.
366 Should be called before the file ABSOLUTE_FILE_NAME is created. */
368 register_temp_file (struct temp_dir *dir,
369 const char *absolute_file_name)
371 struct tempdir *tmpdir = (struct tempdir *)dir;
373 /* Add absolute_file_name to tmpdir->files, without duplicates. */
374 if (gl_list_search (tmpdir->files, absolute_file_name) == NULL)
375 gl_list_add_first (tmpdir->files, xstrdup (absolute_file_name));
378 /* Unregister the given ABSOLUTE_FILE_NAME as being a file inside DIR, that
379 needs to be removed before DIR can be removed.
380 Should be called when the file ABSOLUTE_FILE_NAME could not be created. */
382 unregister_temp_file (struct temp_dir *dir,
383 const char *absolute_file_name)
385 struct tempdir *tmpdir = (struct tempdir *)dir;
386 gl_list_t list = tmpdir->files;
389 node = gl_list_search (list, absolute_file_name);
392 char *old_string = (char *) gl_list_node_value (list, node);
394 gl_list_remove_node (list, node);
399 /* Register the given ABSOLUTE_DIR_NAME as being a subdirectory inside DIR,
400 that needs to be removed before DIR can be removed.
401 Should be called before the subdirectory ABSOLUTE_DIR_NAME is created. */
403 register_temp_subdir (struct temp_dir *dir,
404 const char *absolute_dir_name)
406 struct tempdir *tmpdir = (struct tempdir *)dir;
408 /* Add absolute_dir_name to tmpdir->subdirs, without duplicates. */
409 if (gl_list_search (tmpdir->subdirs, absolute_dir_name) == NULL)
410 gl_list_add_first (tmpdir->subdirs, xstrdup (absolute_dir_name));
413 /* Unregister the given ABSOLUTE_DIR_NAME as being a subdirectory inside DIR,
414 that needs to be removed before DIR can be removed.
415 Should be called when the subdirectory ABSOLUTE_DIR_NAME could not be
418 unregister_temp_subdir (struct temp_dir *dir,
419 const char *absolute_dir_name)
421 struct tempdir *tmpdir = (struct tempdir *)dir;
422 gl_list_t list = tmpdir->subdirs;
425 node = gl_list_search (list, absolute_dir_name);
428 char *old_string = (char *) gl_list_node_value (list, node);
430 gl_list_remove_node (list, node);
435 /* Remove a file, with optional error message.
436 Return 0 upon success, or -1 if there was some problem. */
438 do_unlink (struct temp_dir *dir, const char *absolute_file_name)
440 if (unlink (absolute_file_name) < 0 && dir->cleanup_verbose
443 error (0, errno, _("cannot remove temporary file %s"), absolute_file_name);
449 /* Remove a directory, with optional error message.
450 Return 0 upon success, or -1 if there was some problem. */
452 do_rmdir (struct temp_dir *dir, const char *absolute_dir_name)
454 if (rmdir (absolute_dir_name) < 0 && dir->cleanup_verbose
458 _("cannot remove temporary directory %s"), absolute_dir_name);
464 /* Remove the given ABSOLUTE_FILE_NAME and unregister it.
465 Return 0 upon success, or -1 if there was some problem. */
467 cleanup_temp_file (struct temp_dir *dir,
468 const char *absolute_file_name)
472 err = do_unlink (dir, absolute_file_name);
473 unregister_temp_file (dir, absolute_file_name);
478 /* Remove the given ABSOLUTE_DIR_NAME and unregister it.
479 Return 0 upon success, or -1 if there was some problem. */
481 cleanup_temp_subdir (struct temp_dir *dir,
482 const char *absolute_dir_name)
486 err = do_rmdir (dir, absolute_dir_name);
487 unregister_temp_subdir (dir, absolute_dir_name);
492 /* Remove all registered files and subdirectories inside DIR.
493 Return 0 upon success, or -1 if there was some problem. */
495 cleanup_temp_dir_contents (struct temp_dir *dir)
497 struct tempdir *tmpdir = (struct tempdir *)dir;
500 gl_list_iterator_t iter;
504 /* First cleanup the files in the subdirectories. */
505 list = tmpdir->files;
506 iter = gl_list_iterator (list);
507 while (gl_list_iterator_next (&iter, &element, &node))
509 char *file = (char *) element;
511 err |= do_unlink (dir, file);
512 gl_list_remove_node (list, node);
513 /* Now only we can free file. */
516 gl_list_iterator_free (&iter);
518 /* Then cleanup the subdirectories. */
519 list = tmpdir->subdirs;
520 iter = gl_list_iterator (list);
521 while (gl_list_iterator_next (&iter, &element, &node))
523 char *subdir = (char *) element;
525 err |= do_rmdir (dir, subdir);
526 gl_list_remove_node (list, node);
527 /* Now only we can free subdir. */
530 gl_list_iterator_free (&iter);
535 /* Remove all registered files and subdirectories inside DIR and DIR itself.
536 DIR cannot be used any more after this call.
537 Return 0 upon success, or -1 if there was some problem. */
539 cleanup_temp_dir (struct temp_dir *dir)
541 struct tempdir *tmpdir = (struct tempdir *)dir;
545 err |= cleanup_temp_dir_contents (dir);
546 err |= do_rmdir (dir, tmpdir->dirname);
548 for (i = 0; i < cleanup_list.tempdir_count; i++)
549 if (cleanup_list.tempdir_list[i] == tmpdir)
551 /* Remove cleanup_list.tempdir_list[i]. */
552 if (i + 1 == cleanup_list.tempdir_count)
554 while (i > 0 && cleanup_list.tempdir_list[i - 1] == NULL)
556 cleanup_list.tempdir_count = i;
559 cleanup_list.tempdir_list[i] = NULL;
560 /* Now only we can free the tmpdir->dirname and tmpdir itself. */
561 free (tmpdir->dirname);
566 /* The user passed an invalid DIR argument. */
571 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
573 /* On Windows, opening a file with _O_TEMPORARY has the effect of passing
574 the FILE_FLAG_DELETE_ON_CLOSE flag to CreateFile(), which has the effect
575 of deleting the file when it is closed - even when the program crashes.
576 But (according to the Cygwin sources) it works only on Windows NT or newer.
577 So we cache the info whether we are running on Windows NT or newer. */
580 supports_delete_on_close ()
582 static int known; /* 1 = yes, -1 = no, 0 = unknown */
587 if (GetVersionEx (&v))
588 known = (v.dwPlatformId == VER_PLATFORM_WIN32_NT ? 1 : -1);
598 /* Register a file descriptor to be closed. */
602 if (descriptors == NULL)
603 descriptors = gl_list_create_empty (GL_LINKEDHASH_LIST, NULL, NULL, false);
604 gl_list_add_first (descriptors, (void *) (uintptr_t) fd);
607 /* Unregister a file descriptor to be closed. */
609 unregister_fd (int fd)
611 gl_list_t fds = descriptors;
615 /* descriptors should already contain fd. */
617 node = gl_list_search (fds, (void *) (uintptr_t) fd);
619 /* descriptors should already contain fd. */
621 gl_list_remove_node (fds, node);
624 /* Open a temporary file in a temporary directory.
625 Registers the resulting file descriptor to be closed. */
627 open_temp (const char *file_name, int flags, mode_t mode)
632 block_fatal_signals ();
633 /* Note: 'open' here is actually open() or open_safer(). */
634 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
635 /* Use _O_TEMPORARY when possible, to increase the chances that the
636 temporary file is removed when the process crashes. */
637 if (supports_delete_on_close ())
638 fd = open (file_name, flags | _O_TEMPORARY, mode);
641 fd = open (file_name, flags, mode);
645 unblock_fatal_signals ();
650 /* Open a temporary file in a temporary directory.
651 Registers the resulting file descriptor to be closed. */
653 fopen_temp (const char *file_name, const char *mode)
658 block_fatal_signals ();
659 /* Note: 'fopen' here is actually fopen() or fopen_safer(). */
660 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
661 /* Use _O_TEMPORARY when possible, to increase the chances that the
662 temporary file is removed when the process crashes. */
663 if (supports_delete_on_close ())
665 size_t mode_len = strlen (mode);
666 char *augmented_mode = (char *) xallocsa (mode_len + 2);
667 memcpy (augmented_mode, mode, mode_len);
668 memcpy (augmented_mode + mode_len, "D", 2);
670 fp = fopen (file_name, augmented_mode);
673 freesa (augmented_mode);
678 fp = fopen (file_name, mode);
683 /* It is sufficient to register fileno (fp) instead of the entire fp,
684 because at cleanup time there is no need to do an fflush (fp); a
685 close (fileno (fp)) will be enough. */
686 int fd = fileno (fp);
691 unblock_fatal_signals ();
696 /* Close a temporary file in a temporary directory.
697 Unregisters the previously registered file descriptor. */
703 /* No blocking of signals is needed here, since a double close of a
704 file descriptor is harmless. */
705 int result = close (fd);
706 int saved_errno = errno;
708 /* No race condition here: we assume a single-threaded program, hence
709 fd cannot be re-opened here. */
720 /* Close a temporary file in a temporary directory.
721 Unregisters the previously registered file descriptor. */
723 fclose_temp (FILE *fp)
725 int fd = fileno (fp);
726 /* No blocking of signals is needed here, since a double close of a
727 file descriptor is harmless. */
728 int result = fclose (fp);
729 int saved_errno = errno;
731 /* No race condition here: we assume a single-threaded program, hence
732 fd cannot be re-opened here. */
740 #if GNULIB_FWRITEERROR
742 Unregisters the previously registered file descriptor. */
744 fwriteerror_temp (FILE *fp)
746 int fd = fileno (fp);
747 /* No blocking of signals is needed here, since a double close of a
748 file descriptor is harmless. */
749 int result = fwriteerror (fp);
750 int saved_errno = errno;
752 /* No race condition here: we assume a single-threaded program, hence
753 fd cannot be re-opened here. */
762 #if GNULIB_CLOSE_STREAM
763 /* Like close_stream.
764 Unregisters the previously registered file descriptor. */
766 close_stream_temp (FILE *fp)
768 int fd = fileno (fp);
769 /* No blocking of signals is needed here, since a double close of a
770 file descriptor is harmless. */
771 int result = close_stream (fp);
772 int saved_errno = errno;
774 /* No race condition here: we assume a single-threaded program, hence
775 fd cannot be re-opened here. */