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, 2006, 2007, 2009, 2010 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 3, 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 #ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT
29 # define DOUBLE_SLASH_IS_DISTINCT_ROOT 0
33 /* Handling strings. */
35 /* Assign STRING to a copy of VALUE if not zero, or to zero. If
36 STRING was nonzero, it is freed first. */
38 assign_string (char **string
, const char *value
)
42 *string
= value
? xstrdup (value
) : 0;
46 /* This function is currently unused; perhaps it should be removed? */
48 /* Allocate a copy of the string quoted as in C, and returns that. If
49 the string does not have to be quoted, it returns a null pointer.
50 The allocated copy should normally be freed with free() after the
51 caller is done with it.
53 This is used in one context only: generating the directory file in
54 incremental dumps. The quoted string is not intended for human
55 consumption; it is intended only for unquote_string. The quoting
56 is locale-independent, so that users needn't worry about locale
57 when reading directory files. This means that we can't use
58 quotearg, as quotearg is locale-dependent and is meant for human
61 quote_copy_string (const char *string
)
63 const char *source
= string
;
64 char *destination
= 0;
70 int character
= *source
++;
77 size_t length
= (source
- string
) - 1;
80 buffer
= xmalloc (length
+ 2 + 2 * strlen (source
) + 1);
81 memcpy (buffer
, string
, length
);
82 destination
= buffer
+ length
;
84 *destination
++ = '\\';
85 *destination
++ = character
== '\\' ? '\\' : 'n';
90 *destination
++ = character
;
103 /* Takes a quoted C string (like those produced by quote_copy_string)
104 and turns it back into the un-quoted original. This is done in
105 place. Returns 0 only if the string was not properly quoted, but
106 completes the unquoting anyway.
108 This is used for reading the saved directory file in incremental
109 dumps. It is used for decoding old `N' records (demangling names).
110 But also, it is used for decoding file arguments, would they come
111 from the shell or a -T file, and for decoding the --exclude
114 unquote_string (char *string
)
117 char *source
= string
;
118 char *destination
= string
;
120 /* Escape sequences other than \\ and \n are no longer generated by
121 quote_copy_string, but accept them for backwards compatibility,
122 and also because unquote_string is used for purposes other than
123 parsing the output of quote_copy_string. */
130 *destination
++ = '\\';
135 *destination
++ = '\a';
140 *destination
++ = '\b';
145 *destination
++ = '\f';
150 *destination
++ = '\n';
155 *destination
++ = '\r';
160 *destination
++ = '\t';
165 *destination
++ = '\v';
170 *destination
++ = 0177;
183 int value
= *source
++ - '0';
185 if (*source
< '0' || *source
> '7')
187 *destination
++ = value
;
190 value
= value
* 8 + *source
++ - '0';
191 if (*source
< '0' || *source
> '7')
193 *destination
++ = value
;
196 value
= value
* 8 + *source
++ - '0';
197 *destination
++ = value
;
203 *destination
++ = '\\';
205 *destination
++ = *source
++;
208 else if (source
!= destination
)
209 *destination
++ = *source
++;
211 source
++, destination
++;
213 if (source
!= destination
)
218 /* Zap trailing slashes. */
220 zap_slashes (char *name
)
224 if (!name
|| *name
== 0)
226 q
= name
+ strlen (name
) - 1;
227 while (q
> name
&& ISSLASH (*q
))
232 /* Normalize FILE_NAME by removing redundant slashes and "."
233 components, including redundant trailing slashes. Leave ".."
234 alone, as it may be significant in the presence of symlinks and on
235 platforms where "/.." != "/". Destructive version: modifies its
238 normalize_filename_x (char *file_name
)
240 char *name
= file_name
+ FILE_SYSTEM_PREFIX_LEN (file_name
);
245 /* Don't squeeze leading "//" to "/", on hosts where they're distinct. */
246 name
+= (DOUBLE_SLASH_IS_DISTINCT_ROOT
247 && ISSLASH (*name
) && ISSLASH (name
[1]) && ! ISSLASH (name
[2]));
249 /* Omit redundant leading "." components. */
250 for (q
= p
= name
; (*p
= *q
) == '.' && ISSLASH (q
[1]); p
+= !*q
)
251 for (q
+= 2; ISSLASH (*q
); q
++)
254 /* Copy components from Q to P, omitting redundant slashes and
255 internal "." components. */
256 while ((*p
++ = c
= *q
++) != '\0')
258 while (ISSLASH (q
[*q
== '.']))
259 q
+= (*q
== '.') + 1;
261 /* Omit redundant trailing "." component and slash. */
264 p
-= p
[-2] == '.' && ISSLASH (p
[-3]);
265 p
-= 2 < p
- name
&& ISSLASH (p
[-2]);
270 /* Normalize NAME by removing redundant slashes and "." components,
271 including redundant trailing slashes. Return a normalized
272 newly-allocated copy. */
275 normalize_filename (const char *name
)
279 if (IS_RELATIVE_FILE_NAME (name
))
281 /* Set COPY to the absolute file name if possible.
283 FIXME: There should be no need to get the absolute file name.
284 getcwd is slow, it might fail, and it does not necessarily
285 return a canonical name even when it succeeds. Perhaps we
286 can use dev+ino pairs instead of names? */
290 size_t copylen
= strlen (copy
);
291 bool need_separator
= ! (DOUBLE_SLASH_IS_DISTINCT_ROOT
292 && copylen
== 2 && ISSLASH (copy
[1]));
293 copy
= xrealloc (copy
, copylen
+ need_separator
+ strlen (name
) + 1);
294 copy
[copylen
] = DIRECTORY_SEPARATOR
;
295 strcpy (copy
+ copylen
+ need_separator
, name
);
298 WARN ((0, errno
, _("Cannot get working directory")));
302 copy
= xstrdup (name
);
303 normalize_filename_x (copy
);
309 replace_prefix (char **pname
, const char *samp
, size_t slen
,
310 const char *repl
, size_t rlen
)
313 size_t nlen
= strlen (name
);
314 if (nlen
> slen
&& memcmp (name
, samp
, slen
) == 0 && ISSLASH (name
[slen
]))
318 name
= xrealloc (name
, nlen
- slen
+ rlen
+ 1);
321 memmove (name
+ rlen
, name
+ slen
, nlen
- slen
+ 1);
322 memcpy (name
, repl
, rlen
);
327 /* Handling numbers. */
329 /* Output fraction and trailing digits appropriate for a nanoseconds
330 count equal to NS, but don't output unnecessary '.' or trailing
334 code_ns_fraction (int ns
, char *p
)
353 p
[--i
] = '0' + ns
% 10;
362 code_timespec (struct timespec t
, char sbuf
[TIMESPEC_STRSIZE_BOUND
])
367 bool negative
= s
< 0;
369 /* ignore invalid values of ns */
370 if (BILLION
<= ns
|| ns
< 0)
373 if (negative
&& ns
!= 0)
379 np
= umaxtostr (negative
? - (uintmax_t) s
: (uintmax_t) s
, sbuf
+ 1);
382 code_ns_fraction (ns
, sbuf
+ UINTMAX_STRSIZE_BOUND
);
388 /* Saved names in case backup needs to be undone. */
389 static char *before_backup_name
;
390 static char *after_backup_name
;
392 /* Return 1 if FILE_NAME is obviously "." or "/". */
394 must_be_dot_or_slash (char const *file_name
)
396 file_name
+= FILE_SYSTEM_PREFIX_LEN (file_name
);
398 if (ISSLASH (file_name
[0]))
401 if (ISSLASH (file_name
[1]))
403 else if (file_name
[1] == '.'
404 && ISSLASH (file_name
[2 + (file_name
[2] == '.')]))
405 file_name
+= 2 + (file_name
[2] == '.');
407 return ! file_name
[1];
411 while (file_name
[0] == '.' && ISSLASH (file_name
[1]))
414 while (ISSLASH (*file_name
))
418 return ! file_name
[0] || (file_name
[0] == '.' && ! file_name
[1]);
422 /* Some implementations of rmdir let you remove '.' or '/'.
423 Report an error with errno set to zero for obvious cases of this;
424 otherwise call rmdir. */
426 safer_rmdir (const char *file_name
)
428 if (must_be_dot_or_slash (file_name
))
434 return unlinkat (chdir_fd
, file_name
, AT_REMOVEDIR
);
437 /* Remove FILE_NAME, returning 1 on success. If FILE_NAME is a directory,
438 then if OPTION is RECURSIVE_REMOVE_OPTION is set remove FILE_NAME
439 recursively; otherwise, remove it only if it is empty. If FILE_NAME is
440 a directory that cannot be removed (e.g., because it is nonempty)
441 and if OPTION is WANT_DIRECTORY_REMOVE_OPTION, then return -1.
442 Return 0 on error, with errno set; if FILE_NAME is obviously the working
443 directory return zero with errno set to zero. */
445 remove_any_file (const char *file_name
, enum remove_option option
)
447 /* Try unlink first if we cannot unlink directories, as this saves
448 us a system call in the common case where we're removing a
450 bool try_unlink_first
= cannot_unlink_dir ();
452 if (try_unlink_first
)
454 if (unlinkat (chdir_fd
, file_name
, 0) == 0)
457 /* POSIX 1003.1-2001 requires EPERM when attempting to unlink a
458 directory without appropriate privileges, but many Linux
459 kernels return the more-sensible EISDIR. */
460 if (errno
!= EPERM
&& errno
!= EISDIR
)
464 if (safer_rmdir (file_name
) == 0)
470 return !try_unlink_first
&& unlinkat (chdir_fd
, file_name
, 0) == 0;
474 #if defined ENOTEMPTY && ENOTEMPTY != EEXIST
479 case ORDINARY_REMOVE_OPTION
:
482 case WANT_DIRECTORY_REMOVE_OPTION
:
485 case RECURSIVE_REMOVE_OPTION
:
487 char *directory
= savedir (file_name
);
494 for (entry
= directory
;
495 (entrylen
= strlen (entry
)) != 0;
496 entry
+= entrylen
+ 1)
498 char *file_name_buffer
= new_name (file_name
, entry
);
499 int r
= remove_any_file (file_name_buffer
,
500 RECURSIVE_REMOVE_OPTION
);
502 free (file_name_buffer
);
513 return safer_rmdir (file_name
) == 0;
522 /* Check if FILE_NAME already exists and make a backup of it right now.
523 Return success (nonzero) only if the backup is either unneeded, or
524 successful. For now, directories are considered to never need
525 backup. If THIS_IS_THE_ARCHIVE is nonzero, this is the archive and
526 so, we do not have to backup block or character devices, nor remote
529 maybe_backup_file (const char *file_name
, bool this_is_the_archive
)
531 struct stat file_stat
;
533 assign_string (&before_backup_name
, file_name
);
535 /* A run situation may exist between Emacs or other GNU programs trying to
536 make a backup for the same file simultaneously. If theoretically
537 possible, real problems are unlikely. Doing any better would require a
538 convention, GNU-wide, for all programs doing backups. */
540 assign_string (&after_backup_name
, 0);
542 /* Check if we really need to backup the file. */
544 if (this_is_the_archive
&& _remdev (file_name
))
547 if (deref_stat (file_name
, &file_stat
) != 0)
552 stat_error (file_name
);
556 if (S_ISDIR (file_stat
.st_mode
))
559 if (this_is_the_archive
560 && (S_ISBLK (file_stat
.st_mode
) || S_ISCHR (file_stat
.st_mode
)))
563 after_backup_name
= find_backup_file_name (file_name
, backup_type
);
564 if (! after_backup_name
)
567 if (renameat (chdir_fd
, before_backup_name
, chdir_fd
, after_backup_name
)
571 fprintf (stdlis
, _("Renaming %s to %s\n"),
572 quote_n (0, before_backup_name
),
573 quote_n (1, after_backup_name
));
578 /* The backup operation failed. */
580 ERROR ((0, e
, _("%s: Cannot rename to %s"),
581 quotearg_colon (before_backup_name
),
582 quote_n (1, after_backup_name
)));
583 assign_string (&after_backup_name
, 0);
588 /* Try to restore the recently backed up file to its original name.
589 This is usually only needed after a failed extraction. */
591 undo_last_backup (void)
593 if (after_backup_name
)
595 if (renameat (chdir_fd
, after_backup_name
, chdir_fd
, before_backup_name
)
599 ERROR ((0, e
, _("%s: Cannot rename to %s"),
600 quotearg_colon (after_backup_name
),
601 quote_n (1, before_backup_name
)));
604 fprintf (stdlis
, _("Renaming %s back to %s\n"),
605 quote_n (0, after_backup_name
),
606 quote_n (1, before_backup_name
));
607 assign_string (&after_backup_name
, 0);
611 /* Apply either stat or lstat to (NAME, BUF), depending on the
612 presence of the --dereference option. NAME is relative to the
613 most-recent argument to chdir_do. */
615 deref_stat (char const *name
, struct stat
*buf
)
617 return fstatat (chdir_fd
, name
, buf
, fstatat_flags
);
620 /* Set FD's (i.e., assuming the working directory is PARENTFD, FILE's)
621 access time to ATIME. */
623 set_file_atime (int fd
, int parentfd
, char const *file
, struct timespec atime
)
625 struct timespec ts
[2];
627 ts
[1].tv_nsec
= UTIME_OMIT
;
628 return fdutimensat (fd
, parentfd
, file
, ts
, fstatat_flags
);
631 /* A description of a working directory. */
634 /* The directory's name. */
637 /* If nonzero, the file descriptor of the directory, or AT_FDCWD if
638 the working directory. If zero, the directory needs to be opened
643 /* A vector of chdir targets. wd[0] is the initial working directory. */
644 static struct wd
*wd
;
646 /* The number of working directories in the vector. */
647 static size_t wd_count
;
649 /* The allocated size of the vector. */
650 static size_t wd_alloc
;
652 /* The maximum number of chdir targets with open directories.
653 Don't make it too large, as many operating systems have a small
654 limit on the number of open file descriptors. Also, the current
655 implementation does not scale well. */
656 enum { CHDIR_CACHE_SIZE
= 16 };
658 /* Indexes into WD of chdir targets with open file descriptors, sorted
659 most-recently used first. Zero indexes are unused. */
660 static int wdcache
[CHDIR_CACHE_SIZE
];
662 /* Number of nonzero entries in WDCACHE. */
663 static size_t wdcache_count
;
673 /* DIR is the operand of a -C option; add it to vector of chdir targets,
674 and return the index of its location. */
676 chdir_arg (char const *dir
)
678 if (wd_count
== wd_alloc
)
683 wd
= xmalloc (sizeof *wd
* wd_alloc
);
686 wd
= x2nrealloc (wd
, &wd_alloc
, sizeof *wd
);
690 wd
[wd_count
].name
= ".";
691 wd
[wd_count
].fd
= AT_FDCWD
;
696 /* Optimize the common special case of the working directory,
697 or the working directory as a prefix. */
700 while (dir
[0] == '.' && ISSLASH (dir
[1]))
701 for (dir
+= 2; ISSLASH (*dir
); dir
++)
703 if (! dir
[dir
[0] == '.'])
707 wd
[wd_count
].name
= dir
;
712 /* Index of current directory. */
715 /* Value suitable for use as the first argument to openat, and in
716 similar locations for fstatat, etc. This is an open file
717 descriptor, or AT_FDCWD if the working directory is current. It is
718 valid until the next invocation of chdir_do. */
719 int chdir_fd
= AT_FDCWD
;
721 /* Change to directory I, in a virtual way. This does not actually
722 invoke chdir; it merely sets chdir_fd to an int suitable as the
723 first argument for openat, etc. If I is 0, change to the initial
724 working directory; otherwise, I must be a value returned by
729 if (chdir_current
!= i
)
731 static size_t counter
;
732 struct wd
*curr
= &wd
[i
];
737 if (! IS_ABSOLUTE_FILE_NAME (curr
->name
))
739 fd
= openat (chdir_fd
, curr
->name
, open_searchdir_flags
);
741 open_fatal (curr
->name
);
745 /* Add I to the cache, tossing out the lowest-ranking entry if the
747 if (wdcache_count
< CHDIR_CACHE_SIZE
)
748 wdcache
[wdcache_count
++] = i
;
751 struct wd
*stale
= &wd
[wdcache
[CHDIR_CACHE_SIZE
- 1]];
752 if (close (stale
->fd
) != 0)
753 close_diag (stale
->name
);
755 wdcache
[CHDIR_CACHE_SIZE
- 1] = i
;
761 /* Move the i value to the front of the cache. This is
762 O(CHDIR_CACHE_SIZE), but the cache is small. */
764 int prev
= wdcache
[0];
765 for (ci
= 1; prev
!= i
; ci
++)
767 int curr
= wdcache
[ci
];
782 close_diag (char const *name
)
784 if (ignore_failed_read_option
)
791 open_diag (char const *name
)
793 if (ignore_failed_read_option
)
800 read_diag_details (char const *name
, off_t offset
, size_t size
)
802 if (ignore_failed_read_option
)
803 read_warn_details (name
, offset
, size
);
805 read_error_details (name
, offset
, size
);
809 readlink_diag (char const *name
)
811 if (ignore_failed_read_option
)
812 readlink_warn (name
);
814 readlink_error (name
);
818 savedir_diag (char const *name
)
820 if (ignore_failed_read_option
)
823 savedir_error (name
);
827 seek_diag_details (char const *name
, off_t offset
)
829 if (ignore_failed_read_option
)
830 seek_warn_details (name
, offset
);
832 seek_error_details (name
, offset
);
836 stat_diag (char const *name
)
838 if (ignore_failed_read_option
)
845 file_removed_diag (const char *name
, bool top_level
,
846 void (*diagfn
) (char const *name
))
848 if (!top_level
&& errno
== ENOENT
)
850 WARNOPT (WARN_FILE_REMOVED
,
851 (0, 0, _("%s: File removed before we read it"),
852 quotearg_colon (name
)));
853 set_exit_status (TAREXIT_DIFFERS
);
860 dir_removed_diag (const char *name
, bool top_level
,
861 void (*diagfn
) (char const *name
))
863 if (!top_level
&& errno
== ENOENT
)
865 WARNOPT (WARN_FILE_REMOVED
,
866 (0, 0, _("%s: Directory removed before we read it"),
867 quotearg_colon (name
)));
868 set_exit_status (TAREXIT_DIFFERS
);
875 write_fatal_details (char const *name
, ssize_t status
, size_t size
)
877 write_error_details (name
, status
, size
);
881 /* Fork, aborting if unsuccessful. */
887 call_arg_fatal ("fork", _("child process"));
891 /* Create a pipe, aborting if unsuccessful. */
896 call_arg_fatal ("pipe", _("interprocess channel"));
899 /* Return PTR, aligned upward to the next multiple of ALIGNMENT.
900 ALIGNMENT must be nonzero. The caller must arrange for ((char *)
901 PTR) through ((char *) PTR + ALIGNMENT - 1) to be addressable
905 ptr_align (void *ptr
, size_t alignment
)
908 char *p1
= p0
+ alignment
- 1;
909 return p1
- (size_t) p1
% alignment
;
912 /* Return the address of a page-aligned buffer of at least SIZE bytes.
913 The caller should free *PTR when done with the buffer. */
916 page_aligned_alloc (void **ptr
, size_t size
)
918 size_t alignment
= getpagesize ();
919 size_t size1
= size
+ alignment
;
922 *ptr
= xmalloc (size1
);
923 return ptr_align (*ptr
, alignment
);
930 char *buffer
; /* directory, `/', and directory member */
931 size_t buffer_size
; /* allocated size of name_buffer */
932 size_t dir_length
; /* length of directory part in buffer */
936 namebuf_create (const char *dir
)
938 namebuf_t buf
= xmalloc (sizeof (*buf
));
939 buf
->buffer_size
= strlen (dir
) + 2;
940 buf
->buffer
= xmalloc (buf
->buffer_size
);
941 strcpy (buf
->buffer
, dir
);
942 buf
->dir_length
= strlen (buf
->buffer
);
943 if (!ISSLASH (buf
->buffer
[buf
->dir_length
- 1]))
944 buf
->buffer
[buf
->dir_length
++] = DIRECTORY_SEPARATOR
;
949 namebuf_free (namebuf_t buf
)
956 namebuf_name (namebuf_t buf
, const char *name
)
958 size_t len
= strlen (name
);
959 while (buf
->dir_length
+ len
+ 1 >= buf
->buffer_size
)
960 buf
->buffer
= x2realloc (buf
->buffer
, &buf
->buffer_size
);
961 strcpy (buf
->buffer
+ buf
->dir_length
, name
);