tar: --dereference consistency

This closes another race condition, that occurs when overwriting a
symlink with a regular file.
* NEWS (--dereference consistency): New section.
* doc/tar.texi (Option Summary): Describe new --deference behavior.
(dereference): Likewise.  Remove discussion that I didn't follow,
even before --dereference was changed.
* src/common.h (deref_stat, set_file_atime): Adjust signatures.
* src/compare.c (diff_file, diff_multivol): Respect open_read_flags
instead of rolling our own flags.  This implements the new behavior
for --dereference.
(diff_file, diff_dumpdir): Likewise, for fstatat_flags.
* src/create.c: Adjust to set_file_atime signature change.
* src/extract.c (mark_after_links, file_newer_p, extract_dir):
Likewise.
* src/incremen.c (try_purge_directory): Likewise.
* src/misc.c (maybe_backup_file): Likewise.
* src/extract.c (file_newer_p): New arg STP.  All callers changed.
(maybe_recoverable): New arg REGULAR.  All callers changed.
Handle the case of overwriting a symlink with a regular file,
when --overwrite is specified but --dereference is not.
(open_output_file): Add O_CLOEXEC, O_NOCTTY, O_NONBLOCK for
consistency with file creation.  Add O_NOFOLLOW if
overwriting_old_files && ! dereference_option.
* src/incremen.c (update_parent_directory): Use fstat, not fstatat;
there's less to go wrong.
* src/misc.c (deref_stat): Remove DEREF arg.  All callers changed.
Instead, use fstatat_flags.
(set_file_atime): Remove ATFLAG arg.  All callers changed.
Instead, use fstatat_flags.
* src/names.c, src/update.c: Adjust to deref_stat signature change.
* src/tar.c (get_date_or_file): Use stat, not deref_stat, as this
is not a file to be archived.
* tests/Makefile.am (TESTSUITE_AT): Add extrac13.at.
* tests/extrac13.at: New file.
* tests/testsuite.at: Include it.
This commit is contained in:
Paul Eggert
2010-09-23 19:41:47 -07:00
parent efe26f98ec
commit 14efeb9f95
14 changed files with 195 additions and 122 deletions
+17 -1
View File
@@ -1,4 +1,4 @@
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>
@@ -33,6 +33,22 @@ supports this. For example, recent versions of the Linux kernel
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