-GNU tar NEWS - User visible changes. 2010-09-17
+GNU tar NEWS - User visible changes. 2010-09-23
Please send GNU tar bug reports to <bug-tar@gnu.org>
\f
support setting times on symlinks, and some BSD kernels also support
symlink permissions.
+** --dereference consistency
+
+The --dereference (-h) option now applies to files that are copied
+into or out of archives, independently of other options. For example,
+if F is a symbolic link and archive.tar contains a regular-file member
+also named F, "tar --overwrite -x -f archive.tar F" now overwrites F
+itself, rather than the file that F points to. (To overwrite the file
+that F points to, add the --dereference (-h) option.) Formerly,
+--dereference was intended to apply only when using the -c option, but
+the implementation was not consistent.
+
+Also, the --dereference option no longer affects accesses to other
+files, such as archives and time stamp files. Symbolic links to these
+files are always followed. Previously, the links were usually but not
+always followed.
+
** Spurious error diagnostics on broken pipe.
When receiving SIGPIPE, tar would exit with error status and
@item --dereference
@itemx -h
-When creating a @command{tar} archive, @command{tar} will archive the
-file that a symbolic link points to, rather than archiving the
-symlink. @xref{dereference}.
+When reading or writing a file to be archived, @command{tar} accesses
+the file that a symbolic link points to, rather than the symlink
+itself. @xref{dereference}.
@opsummary{directory}
@item --directory=@var{dir}
Normally, when @command{tar} archives a symbolic link, it writes a
block to the archive naming the target of the link. In that way, the
@command{tar} archive is a faithful record of the file system contents.
-@option{--dereference} (@option{-h}) is used with @option{--create} (@option{-c}), and causes
-@command{tar} to archive the files symbolic links point to, instead of
-the links themselves. When this option is used, when @command{tar}
-encounters a symbolic link, it will archive the linked-to file,
-instead of simply recording the presence of a symbolic link.
-
-The name under which the file is stored in the file system is not
-recorded in the archive. To record both the symbolic link name and
-the file name in the system, archive the file under both names. If
-all links were recorded automatically by @command{tar}, an extracted file
-might be linked to a file name that no longer exists in the file
-system.
-
-If a linked-to file is encountered again by @command{tar} while creating
-the same archive, an entire second copy of it will be stored. (This
-@emph{might} be considered a bug.)
+When @option{--dereference} (@option{-h}) is used with
+@option{--create} (@option{-c}), @command{tar} archives the files
+symbolic links point to, instead of
+the links themselves.
-So, for portable archives, do not archive symbolic links as such,
-and use @option{--dereference} (@option{-h}): many systems do not support
+When creating portable archives, use @option{--dereference}
+(@option{-h}): some systems do not support
symbolic links, and moreover, your distribution might be unusable if
it contains unresolved symbolic links.
-The @option{--dereference} option is not secure if an untrusted user
-can modify files during creation or extraction. @xref{Security}.
+When reading from an archive, the @option{--dereference} (@option{-h})
+option causes @command{tar} to follow an already-existing symbolic
+link when @command{tar} writes or reads a file named in the archive.
+Ordinarily, @command{tar} does not follow such a link, though it may
+remove the link before writing a new file. @xref{Dealing with Old
+Files}.
+
+The @option{--dereference} option is unsafe if an untrusted user can
+modify directories while @command{tar} is running. @xref{Security}.
@node hard links
@subsection Hard Links
bool maybe_backup_file (const char *file_name, bool this_is_the_archive);
void undo_last_backup (void);
-int deref_stat (bool deref, char const *name, struct stat *buf);
+int deref_stat (char const *name, struct stat *buf);
extern int chdir_current;
extern int chdir_fd;
void *page_aligned_alloc (void **ptr, size_t size);
int set_file_atime (int fd, int parentfd, char const *file,
- struct timespec atime, int atflag);
+ struct timespec atime);
/* Module names.c. */
static int
get_stat_data (char const *file_name, struct stat *stat_data)
{
- int status = deref_stat (dereference_option, file_name, stat_data);
+ int status = deref_stat (file_name, stat_data);
if (status != 0)
{
}
else
{
- int atime_flag =
- (atime_preserve_option == system_atime_preserve
- ? O_NOATIME
- : 0);
-
- diff_handle = openat (chdir_fd, file_name,
- (O_RDONLY | O_BINARY | O_CLOEXEC | O_NOCTTY
- | O_NONBLOCK | atime_flag));
+ diff_handle = openat (chdir_fd, file_name, open_read_flags);
if (diff_handle < 0)
{
if (atime_preserve_option == replace_atime_preserve)
{
struct timespec atime = get_stat_atime (&stat_data);
- if (set_file_atime (diff_handle, chdir_fd, file_name,
- atime, 0)
+ if (set_file_atime (diff_handle, chdir_fd, file_name, atime)
!= 0)
utime_error (file_name);
}
dev_t dev = 0;
struct stat stat_data;
- if (deref_stat (true, current_stat_info.file_name, &stat_data))
+ if (deref_stat (current_stat_info.file_name, &stat_data) != 0)
{
if (errno == ENOENT)
stat_warn (current_stat_info.file_name);
struct stat stat_data;
int fd, status;
off_t offset;
- int atime_flag =
- (atime_preserve_option == system_atime_preserve
- ? O_NOATIME
- : 0);
if (current_stat_info.had_trailing_slash)
{
}
- fd = openat (chdir_fd, current_stat_info.file_name,
- (O_RDONLY | O_BINARY | O_CLOEXEC | O_NOCTTY | O_NONBLOCK
- | atime_flag));
+ fd = openat (chdir_fd, current_stat_info.file_name, open_read_flags);
if (fd < 0)
{
set_exit_status (TAREXIT_DIFFERS);
}
else if (atime_preserve_option == replace_atime_preserve
- && (set_file_atime (fd, parentfd, name,
- st->atime, fstatat_flags)
- != 0))
+ && set_file_atime (fd, parentfd, name, st->atime) != 0)
utime_error (p);
}
struct stat st;
h->after_links = 1;
- if (fstatat (chdir_fd, h->file_name, &st, 0) != 0)
+ if (deref_stat (h->file_name, &st) != 0)
stat_error (h->file_name);
else
{
return did_something; /* tell them to retry if we made one */
}
+/* Return true if FILE_NAME (with status *STP, if STP) is not a
+ directory, and has a time stamp newer than (or equal to) that of
+ TAR_STAT. */
static bool
-file_newer_p (const char *file_name, struct tar_stat_info *tar_stat)
+file_newer_p (const char *file_name, struct stat const *stp,
+ struct tar_stat_info *tar_stat)
{
struct stat st;
- if (fstatat (chdir_fd, file_name, &st, 0))
+ if (!stp)
{
- if (errno != ENOENT)
+ if (deref_stat (file_name, &st) != 0)
{
- stat_warn (file_name);
- /* Be on the safe side: if the file does exist assume it is newer */
- return true;
+ if (errno != ENOENT)
+ {
+ stat_warn (file_name);
+ /* Be safer: if the file exists, assume it is newer. */
+ return true;
+ }
+ return false;
}
- return false;
- }
- if (!S_ISDIR (st.st_mode)
- && tar_timespec_cmp (tar_stat->mtime, get_stat_mtime (&st)) <= 0)
- {
- return true;
+ stp = &st;
}
- return false;
+
+ return (! S_ISDIR (stp->st_mode)
+ && tar_timespec_cmp (tar_stat->mtime, get_stat_mtime (stp)) <= 0);
}
#define RECOVER_NO 0
Return RECOVER_OK if we somewhat increased our chances at a successful
extraction, RECOVER_NO if there are no chances, and RECOVER_SKIP if the
caller should skip extraction of that member. The value of errno is
- properly restored on returning RECOVER_NO. */
+ properly restored on returning RECOVER_NO.
+
+ If REGULAR, the caller was trying to extract onto a regular file.
+
+ Set *INTERDIR_MADE if an intermediate directory is made as part of
+ the recovery process. */
static int
-maybe_recoverable (char *file_name, bool *interdir_made)
+maybe_recoverable (char *file_name, bool regular, bool *interdir_made)
{
int e = errno;
+ struct stat st;
+ struct stat const *stp = 0;
if (*interdir_made)
return RECOVER_NO;
- switch (errno)
+ switch (e)
{
+ case ELOOP:
+ if (! regular
+ || old_files_option != OVERWRITE_OLD_FILES || dereference_option)
+ break;
+ if (strchr (file_name, '/'))
+ {
+ if (deref_stat (file_name, &st) != 0)
+ break;
+ stp = &st;
+ }
+
+ /* The caller tried to open a symbolic link with O_NOFOLLOW.
+ Fall through, treating it as an already-existing file. */
+
case EEXIST:
/* Remove an old file, if the options allow this. */
return RECOVER_SKIP;
case KEEP_NEWER_FILES:
- if (file_newer_p (file_name, ¤t_stat_info))
- {
- errno = e;
- return RECOVER_NO;
- }
+ if (file_newer_p (file_name, stp, ¤t_stat_info))
+ break;
/* FALL THROUGH */
case DEFAULT_OLD_FILES:
case NO_OVERWRITE_DIR_OLD_FILES:
case OVERWRITE_OLD_FILES:
- {
- int r = remove_any_file (file_name, ORDINARY_REMOVE_OPTION);
- errno = EEXIST;
- return r > 0 ? RECOVER_OK : RECOVER_NO;
- }
+ if (0 < remove_any_file (file_name, ORDINARY_REMOVE_OPTION))
+ return RECOVER_OK;
+ break;
case UNLINK_FIRST_OLD_FILES:
break;
case ENOENT:
/* Attempt creating missing intermediate directories. */
- if (! make_directories (file_name))
+ if (make_directories (file_name))
{
- errno = ENOENT;
- return RECOVER_NO;
+ *interdir_made = true;
+ return RECOVER_OK;
}
- *interdir_made = true;
- return RECOVER_OK;
+ break;
default:
/* Just say we can't do anything about it... */
-
- return RECOVER_NO;
+ break;
}
+
+ errno = e;
+ return RECOVER_NO;
}
/* Fix the statuses of all directories whose statuses need fixing, and
|| old_files_option == OVERWRITE_OLD_FILES))
{
struct stat st;
- if (fstatat (chdir_fd, file_name, &st, 0) == 0)
+ if (deref_stat (file_name, &st) == 0)
{
current_mode = st.st_mode;
current_mode_mask = ALL_MODE_BITS;
errno = EEXIST;
}
- switch (maybe_recoverable (file_name, &interdir_made))
+ switch (maybe_recoverable (file_name, false, &interdir_made))
{
case RECOVER_OK:
continue;
{
int fd;
bool overwriting_old_files = old_files_option == OVERWRITE_OLD_FILES;
- int openflag = (O_WRONLY | O_BINARY | O_CREAT
- | (overwriting_old_files ? O_TRUNC : O_EXCL));
+ int openflag = (O_WRONLY | O_BINARY | O_CLOEXEC | O_NOCTTY | O_NONBLOCK
+ | O_CREAT
+ | (overwriting_old_files
+ ? O_TRUNC | (dereference_option ? 0 : O_NOFOLLOW)
+ : O_EXCL));
if (typeflag == CONTTYPE)
{
}
else
{
- int recover = RECOVER_NO;
- do
- fd = open_output_file (file_name, typeflag, mode,
- ¤t_mode, ¤t_mode_mask);
- while (fd < 0
- && (recover = maybe_recoverable (file_name, &interdir_made))
- == RECOVER_OK);
-
- if (fd < 0)
+ while ((fd = open_output_file (file_name, typeflag, mode,
+ ¤t_mode, ¤t_mode_mask))
+ < 0)
{
- skip_member ();
- if (recover == RECOVER_SKIP)
- return 0;
- open_error (file_name);
- return 1;
+ int recover = maybe_recoverable (file_name, true, &interdir_made);
+ if (recover != RECOVER_OK)
+ {
+ skip_member ();
+ if (recover == RECOVER_SKIP)
+ return 0;
+ open_error (file_name);
+ return 1;
+ }
}
}
while ((fd = openat (chdir_fd, file_name, O_WRONLY | O_CREAT | O_EXCL, 0)) < 0)
{
- switch (maybe_recoverable (file_name, interdir_made))
+ switch (maybe_recoverable (file_name, false, interdir_made))
{
case RECOVER_OK:
continue;
errno = e;
}
- while ((rc = maybe_recoverable (file_name, &interdir_made)) == RECOVER_OK);
+ while ((rc = maybe_recoverable (file_name, false, &interdir_made))
+ == RECOVER_OK);
if (rc == RECOVER_SKIP)
return 0;
return create_placeholder_file (file_name, true, &interdir_made);
while (symlinkat (current_stat_info.link_name, chdir_fd, file_name) != 0)
- switch (maybe_recoverable (file_name, &interdir_made))
+ switch (maybe_recoverable (file_name, false, &interdir_made))
{
case RECOVER_OK:
continue;
while (mknodat (chdir_fd, file_name, mode, current_stat_info.stat.st_rdev)
!= 0)
- switch (maybe_recoverable (file_name, &interdir_made))
+ switch (maybe_recoverable (file_name, false, &interdir_made))
{
case RECOVER_OK:
continue;
& ~ (0 < same_owner_option ? S_IRWXG | S_IRWXO : 0));
while (mkfifoat (chdir_fd, file_name, mode) != 0)
- switch (maybe_recoverable (file_name, &interdir_made))
+ switch (maybe_recoverable (file_name, false, &interdir_made))
{
case RECOVER_OK:
continue;
break;
case KEEP_NEWER_FILES:
- if (file_newer_p (file_name, ¤t_stat_info))
+ if (file_newer_p (file_name, 0, ¤t_stat_info))
{
WARNOPT (WARN_IGNORE_NEWER,
(0, 0, _("Current %s is newer or same age"),
if (directory)
{
struct stat st;
- if (fstatat (parent->fd, ".", &st, fstatat_flags) != 0)
+ if (fstat (parent->fd, &st) != 0)
stat_diag (directory->name);
else
directory->mtime = get_stat_mtime (&st);
free (p);
p = new_name (directory_name, cur);
- if (deref_stat (false, p, &st))
+ if (deref_stat (p, &st) != 0)
{
if (errno != ENOENT) /* FIXME: Maybe keep a list of renamed
dirs and check it here? */
if (this_is_the_archive && _remdev (file_name))
return true;
- if (fstatat (chdir_fd, file_name, &file_stat, 0))
+ if (deref_stat (file_name, &file_stat) != 0)
{
if (errno == ENOENT)
return true;
}
}
-/* Depending on DEREF, apply either stat or lstat to (NAME, BUF). */
+/* Apply either stat or lstat to (NAME, BUF), depending on the
+ presence of the --dereference option. NAME is relative to the
+ most-recent argument to chdir_do. */
int
-deref_stat (bool deref, char const *name, struct stat *buf)
+deref_stat (char const *name, struct stat *buf)
{
- return fstatat (chdir_fd, name, buf, deref ? 0 : AT_SYMLINK_NOFOLLOW);
+ return fstatat (chdir_fd, name, buf, fstatat_flags);
}
/* Set FD's (i.e., assuming the working directory is PARENTFD, FILE's)
- access time to ATIME. ATFLAG controls symbolic-link following, in
- the style of openat. */
+ access time to ATIME. */
int
-set_file_atime (int fd, int parentfd, char const *file, struct timespec atime,
- int atflag)
+set_file_atime (int fd, int parentfd, char const *file, struct timespec atime)
{
struct timespec ts[2];
ts[0] = atime;
ts[1].tv_nsec = UTIME_OMIT;
- return fdutimensat (fd, parentfd, file, ts, atflag);
+ return fdutimensat (fd, parentfd, file, ts, fstatat_flags);
}
/* A description of a working directory. */
tar_stat_init (&st);
- if (deref_stat (dereference_option, name->name, &st.stat) != 0)
+ if (deref_stat (name->name, &st.stat) != 0)
{
stat_diag (name->name);
continue;
{
struct stat st;
- if (deref_stat (dereference_option, name, &st) != 0)
+ if (deref_stat (name, &st) != 0)
return; /* Will be complained about later */
if (S_ISDIR (st.st_mode))
return;
|| *str == '.')
{
struct stat st;
- if (deref_stat (dereference_option, str, &st) != 0)
+ if (stat (str, &st) != 0)
{
stat_error (str);
USAGE_ERROR ((0, 0, _("Date sample file not found")));
struct stat s;
chdir_do (name->change_dir);
- if (deref_stat (dereference_option,
- current_stat_info.file_name, &s) == 0)
+ if (deref_stat (current_stat_info.file_name, &s) == 0)
{
if (S_ISDIR (s.st_mode))
{
extrac10.at\
extrac11.at\
extrac12.at\
+ extrac13.at\
filerem01.at\
filerem02.at\
gzip.at\
--- /dev/null
+# Process this file with autom4te to create testsuite. -*- Autotest -*-
+
+# Test suite for GNU tar.
+# Copyright (C) 2010 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# written by Paul Eggert
+
+# Check that 'tar' normally does follow symbolic links when extracting,
+# unless --dereference is specified.
+
+AT_SETUP([extract over symlinks])
+AT_KEYWORDS([extract extrac13])
+
+AT_TAR_CHECK([
+mkdir src dst1 dst2 dst3
+echo file1 >src/file1
+ln -s target1 dst1/file1
+echo target1 >dst1/target1
+echo target1 >target1
+
+tar -cf archive.tar -C src . &&
+tar -xf archive.tar -C dst1 &&
+diff -c src/file1 dst1/file1 &&
+diff -c target1 dst1/target1
+
+ln -s target1 dst2/file1
+echo target1 >dst2/target1
+tar --overwrite -xf archive.tar -C dst2 &&
+diff -c src/file1 dst2/file1 &&
+diff -c target1 dst2/target1
+
+ln -s target1 dst3/file1
+echo target1 >dst3/target1
+tar --overwrite -xhf archive.tar -C dst3 &&
+diff -c src/file1 dst3/file1 &&
+diff -c src/file1 dst3/target1
+],
+[0],[],[],[],[],[gnu])
+
+AT_CLEANUP
m4_include([extrac10.at])
m4_include([extrac11.at])
m4_include([extrac12.at])
+m4_include([extrac13.at])
m4_include([label01.at])
m4_include([label02.at])
projects / chaz / tar / commitdiff
