1 /* Miscellaneous functions, not really specific to GNU tar.
3 Copyright (C) 1988, 1992, 1994, 1995, 1996, 1997, 1999, 2000, 2001,
4 2003, 2004, 2005 Free Software Foundation, Inc.
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any later
11 This program is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
14 Public License for more details.
16 You should have received a copy of the GNU General Public License along
17 with this program; if not, write to the Free Software Foundation, Inc.,
18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
25 #include <unlinkdir.h>
28 /* Handling strings. */
30 /* Assign STRING to a copy of VALUE if not zero, or to zero. If
31 STRING was nonzero, it is freed first. */
33 assign_string (char **string
, const char *value
)
37 *string
= value
? xstrdup (value
) : 0;
40 /* Allocate a copy of the string quoted as in C, and returns that. If
41 the string does not have to be quoted, it returns a null pointer.
42 The allocated copy should normally be freed with free() after the
43 caller is done with it.
45 This is used in one context only: generating the directory file in
46 incremental dumps. The quoted string is not intended for human
47 consumption; it is intended only for unquote_string. The quoting
48 is locale-independent, so that users needn't worry about locale
49 when reading directory files. This means that we can't use
50 quotearg, as quotearg is locale-dependent and is meant for human
53 quote_copy_string (const char *string
)
55 const char *source
= string
;
56 char *destination
= 0;
62 int character
= *source
++;
69 size_t length
= (source
- string
) - 1;
72 buffer
= xmalloc (length
+ 2 + 2 * strlen (source
) + 1);
73 memcpy (buffer
, string
, length
);
74 destination
= buffer
+ length
;
76 *destination
++ = '\\';
77 *destination
++ = character
== '\\' ? '\\' : 'n';
82 *destination
++ = character
;
94 /* Takes a quoted C string (like those produced by quote_copy_string)
95 and turns it back into the un-quoted original. This is done in
96 place. Returns 0 only if the string was not properly quoted, but
97 completes the unquoting anyway.
99 This is used for reading the saved directory file in incremental
100 dumps. It is used for decoding old `N' records (demangling names).
101 But also, it is used for decoding file arguments, would they come
102 from the shell or a -T file, and for decoding the --exclude
105 unquote_string (char *string
)
108 char *source
= string
;
109 char *destination
= string
;
111 /* Escape sequences other than \\ and \n are no longer generated by
112 quote_copy_string, but accept them for backwards compatibility,
113 and also because unquote_string is used for purposes other than
114 parsing the output of quote_copy_string. */
121 *destination
++ = '\\';
126 *destination
++ = '\a';
131 *destination
++ = '\b';
136 *destination
++ = '\f';
141 *destination
++ = '\n';
146 *destination
++ = '\r';
151 *destination
++ = '\t';
156 *destination
++ = '\v';
161 *destination
++ = 0177;
174 int value
= *source
++ - '0';
176 if (*source
< '0' || *source
> '7')
178 *destination
++ = value
;
181 value
= value
* 8 + *source
++ - '0';
182 if (*source
< '0' || *source
> '7')
184 *destination
++ = value
;
187 value
= value
* 8 + *source
++ - '0';
188 *destination
++ = value
;
194 *destination
++ = '\\';
196 *destination
++ = *source
++;
199 else if (source
!= destination
)
200 *destination
++ = *source
++;
202 source
++, destination
++;
204 if (source
!= destination
)
209 /* Handling numbers. */
211 /* Output fraction and trailing digits appropriate for a nanoseconds
212 count equal to NS, but don't output unnecessary '.' or trailing
216 code_ns_fraction (int ns
, char *p
)
235 p
[--i
] = '0' + ns
% 10;
245 /* Saved names in case backup needs to be undone. */
246 static char *before_backup_name
;
247 static char *after_backup_name
;
249 /* Return 1 if FILE_NAME is obviously "." or "/". */
251 must_be_dot_or_slash (char const *file_name
)
253 file_name
+= FILE_SYSTEM_PREFIX_LEN (file_name
);
255 if (ISSLASH (file_name
[0]))
258 if (ISSLASH (file_name
[1]))
260 else if (file_name
[1] == '.'
261 && ISSLASH (file_name
[2 + (file_name
[2] == '.')]))
262 file_name
+= 2 + (file_name
[2] == '.');
264 return ! file_name
[1];
268 while (file_name
[0] == '.' && ISSLASH (file_name
[1]))
271 while (ISSLASH (*file_name
))
275 return ! file_name
[0] || (file_name
[0] == '.' && ! file_name
[1]);
279 /* Some implementations of rmdir let you remove '.' or '/'.
280 Report an error with errno set to zero for obvious cases of this;
281 otherwise call rmdir. */
283 safer_rmdir (const char *file_name
)
285 if (must_be_dot_or_slash (file_name
))
291 return rmdir (file_name
);
294 /* Remove FILE_NAME, returning 1 on success. If FILE_NAME is a directory,
295 then if OPTION is RECURSIVE_REMOVE_OPTION is set remove FILE_NAME
296 recursively; otherwise, remove it only if it is empty. If FILE_NAME is
297 a directory that cannot be removed (e.g., because it is nonempty)
298 and if OPTION is WANT_DIRECTORY_REMOVE_OPTION, then return -1.
299 Return 0 on error, with errno set; if FILE_NAME is obviously the working
300 directory return zero with errno set to zero. */
302 remove_any_file (const char *file_name
, enum remove_option option
)
304 /* Try unlink first if we cannot unlink directories, as this saves
305 us a system call in the common case where we're removing a
307 bool try_unlink_first
= cannot_unlink_dir ();
309 if (try_unlink_first
)
311 if (unlink (file_name
) == 0)
314 /* POSIX 1003.1-2001 requires EPERM when attempting to unlink a
315 directory without appropriate privileges, but many Linux
316 kernels return the more-sensible EISDIR. */
317 if (errno
!= EPERM
&& errno
!= EISDIR
)
321 if (safer_rmdir (file_name
) == 0)
327 return !try_unlink_first
&& unlink (file_name
) == 0;
331 #if defined ENOTEMPTY && ENOTEMPTY != EEXIST
336 case ORDINARY_REMOVE_OPTION
:
339 case WANT_DIRECTORY_REMOVE_OPTION
:
342 case RECURSIVE_REMOVE_OPTION
:
344 char *directory
= savedir (file_name
);
351 for (entry
= directory
;
352 (entrylen
= strlen (entry
)) != 0;
353 entry
+= entrylen
+ 1)
355 char *file_name_buffer
= new_name (file_name
, entry
);
356 int r
= remove_any_file (file_name_buffer
,
357 RECURSIVE_REMOVE_OPTION
);
359 free (file_name_buffer
);
370 return safer_rmdir (file_name
) == 0;
379 /* Check if FILE_NAME already exists and make a backup of it right now.
380 Return success (nonzero) only if the backup is either unneeded, or
381 successful. For now, directories are considered to never need
382 backup. If THIS_IS_THE_ARCHIVE is nonzero, this is the archive and
383 so, we do not have to backup block or character devices, nor remote
386 maybe_backup_file (const char *file_name
, int this_is_the_archive
)
388 struct stat file_stat
;
390 /* Check if we really need to backup the file. */
392 if (this_is_the_archive
&& _remdev (file_name
))
395 if (stat (file_name
, &file_stat
))
400 stat_error (file_name
);
404 if (S_ISDIR (file_stat
.st_mode
))
407 if (this_is_the_archive
408 && (S_ISBLK (file_stat
.st_mode
) || S_ISCHR (file_stat
.st_mode
)))
411 assign_string (&before_backup_name
, file_name
);
413 /* A run situation may exist between Emacs or other GNU programs trying to
414 make a backup for the same file simultaneously. If theoretically
415 possible, real problems are unlikely. Doing any better would require a
416 convention, GNU-wide, for all programs doing backups. */
418 assign_string (&after_backup_name
, 0);
419 after_backup_name
= find_backup_file_name (file_name
, backup_type
);
420 if (! after_backup_name
)
423 if (rename (before_backup_name
, after_backup_name
) == 0)
426 fprintf (stdlis
, _("Renaming %s to %s\n"),
427 quote_n (0, before_backup_name
),
428 quote_n (1, after_backup_name
));
433 /* The backup operation failed. */
435 ERROR ((0, e
, _("%s: Cannot rename to %s"),
436 quotearg_colon (before_backup_name
),
437 quote_n (1, after_backup_name
)));
438 assign_string (&after_backup_name
, 0);
443 /* Try to restore the recently backed up file to its original name.
444 This is usually only needed after a failed extraction. */
446 undo_last_backup (void)
448 if (after_backup_name
)
450 if (rename (after_backup_name
, before_backup_name
) != 0)
453 ERROR ((0, e
, _("%s: Cannot rename to %s"),
454 quotearg_colon (after_backup_name
),
455 quote_n (1, before_backup_name
)));
458 fprintf (stdlis
, _("Renaming %s back to %s\n"),
459 quote_n (0, after_backup_name
),
460 quote_n (1, before_backup_name
));
461 assign_string (&after_backup_name
, 0);
465 /* Depending on DEREF, apply either stat or lstat to (NAME, BUF). */
467 deref_stat (bool deref
, char const *name
, struct stat
*buf
)
469 return deref
? stat (name
, buf
) : lstat (name
, buf
);
472 /* A description of a working directory. */
477 struct saved_cwd saved_cwd
;
480 /* A vector of chdir targets. wd[0] is the initial working directory. */
481 static struct wd
*wd
;
483 /* The number of working directories in the vector. */
486 /* The allocated size of the vector. */
487 static size_t wd_alloc
;
489 /* DIR is the operand of a -C option; add it to vector of chdir targets,
490 and return the index of its location. */
492 chdir_arg (char const *dir
)
496 wd_alloc
= 2 * (wd_alloc
+ 1);
497 wd
= xrealloc (wd
, sizeof *wd
* wd_alloc
);
506 /* Optimize the common special case of the working directory,
507 or the working directory as a prefix. */
510 while (dir
[0] == '.' && ISSLASH (dir
[1]))
511 for (dir
+= 2; ISSLASH (*dir
); dir
++)
513 if (! dir
[dir
[0] == '.'])
522 /* Change to directory I. If I is 0, change to the initial working
523 directory; otherwise, I must be a value returned by chdir_arg. */
531 struct wd
*prev
= &wd
[previous
];
532 struct wd
*curr
= &wd
[i
];
537 if (save_cwd (&prev
->saved_cwd
) != 0)
538 FATAL_ERROR ((0, 0, _("Cannot save working directory")));
543 if (restore_cwd (&curr
->saved_cwd
))
544 FATAL_ERROR ((0, 0, _("Cannot change working directory")));
548 if (i
&& ! ISSLASH (curr
->name
[0]))
550 if (chdir (curr
->name
) != 0)
551 chdir_fatal (curr
->name
);
559 close_diag (char const *name
)
561 if (ignore_failed_read_option
)
568 open_diag (char const *name
)
570 if (ignore_failed_read_option
)
577 read_diag_details (char const *name
, off_t offset
, size_t size
)
579 if (ignore_failed_read_option
)
580 read_warn_details (name
, offset
, size
);
582 read_error_details (name
, offset
, size
);
586 readlink_diag (char const *name
)
588 if (ignore_failed_read_option
)
589 readlink_warn (name
);
591 readlink_error (name
);
595 savedir_diag (char const *name
)
597 if (ignore_failed_read_option
)
600 savedir_error (name
);
604 seek_diag_details (char const *name
, off_t offset
)
606 if (ignore_failed_read_option
)
607 seek_warn_details (name
, offset
);
609 seek_error_details (name
, offset
);
613 stat_diag (char const *name
)
615 if (ignore_failed_read_option
)
622 write_fatal_details (char const *name
, ssize_t status
, size_t size
)
624 write_error_details (name
, status
, size
);
628 /* Fork, aborting if unsuccessful. */
634 call_arg_fatal ("fork", _("child process"));
638 /* Create a pipe, aborting if unsuccessful. */
643 call_arg_fatal ("pipe", _("interprocess channel"));
646 /* Return PTR, aligned upward to the next multiple of ALIGNMENT.
647 ALIGNMENT must be nonzero. The caller must arrange for ((char *)
648 PTR) through ((char *) PTR + ALIGNMENT - 1) to be addressable
652 ptr_align (void *ptr
, size_t alignment
)
655 char *p1
= p0
+ alignment
- 1;
656 return p1
- (size_t) p1
% alignment
;
659 /* Return the address of a page-aligned buffer of at least SIZE bytes.
660 The caller should free *PTR when done with the buffer. */
663 page_aligned_alloc (void **ptr
, size_t size
)
665 size_t alignment
= getpagesize ();
666 size_t size1
= size
+ alignment
;
669 *ptr
= xmalloc (size1
);
670 return ptr_align (*ptr
, alignment
);