From c4a4cafaa330793d776b001c272bf19869aac39c Mon Sep 17 00:00:00 2001

From: Sergey Poznyakoff <gray@gnu.org.ua>

Date: Mon, 23 Sep 2013 19:35:29 +0300

Subject: [PATCH] Changes for compatibility with Slackware installation

 scripts.

* src/buffer.c (short_read): the "Record size" message

is controlled by the WARN_RECORD_SIZE warning_option bit.

* src/common.h (keep_directory_symlink_option): New global.

(WARN_RECORD_SIZE): New constant.

(WARN_VERBOSE_WARNINGS): Add WARN_RECORD_SIZE.

* src/extract.c (extract_dir): If keep_directory_symlink_option is

set, follow symlinks to directories.

* src/suffix.c (compression_suffixes): Add support for txz

suffix.

* src/tar.c (KEEP_DIRECTORY_SYMLINK_OPTION): New constant.

(options): New option --keep-directory-symlink.

(parse_opt): Handle this option.

* src/warning.c: Implement "record-size" warning control.

* NEWS: Update.

* doc/tar.texi: Document new features.

---

 NEWS          | 12 ++++++++++++

 doc/tar.texi  | 15 +++++++++++++++

 src/common.h  |  2 ++

 src/extract.c | 19 +++++++++++++++++++

 src/tar.c     |  8 ++++++++

 5 files changed, 56 insertions(+)

diff --git a/NEWS b/NEWS

index 8f3c416..36a27da 100644

--- a/NEWS

+++ b/NEWS

@@ -6,6 +6,18 @@ Please send GNU tar bug reports to <bug-tar@gnu.org>

 When creating a PAX-format archive, tar no longer arbitrarily restricts

 the size of the representation of a sparse file to be less than 8 GiB.

+* New command line option --keep-directory-symlink

+

+By default, if when trying to extract a directory from the archive,

+tar discovers that the corresponding file name already exists and is a

+symbolic link, it first unlinks the entry, and then extracts the directory.

+

+This option disables this behavior and instructs tar to follow

+symlinks to directories when extracting from the archive.

+

+It is mainly intended to provide compatibility with the Slackware

+installation scripts.

+

 version 1.26 - Sergey Poznyakoff, 2011-03-12

diff --git a/doc/tar.texi b/doc/tar.texi

index 6bd59c7..fb03b85 100644

--- a/doc/tar.texi

+++ b/doc/tar.texi

@@ -2923,6 +2923,21 @@ Specifies that @command{tar} should ask the user for confirmation before

 performing potentially destructive options, such as overwriting files.

 @xref{interactive}.

+@opsummary{--keep-directory-symlink}

+@item --keep-directory-symlink

+

+This option changes the behavior of tar when it encounters a symlink

+with the same name as the directory that it is about to extract.  By

+default, in this case tar would first remove the symlink and then

+proceed extracting the directory.

+

+The @option{--keep-directory-symlink} option disables this behavior

+and instructs tar to follow symlinks to directories when extracting

+from the archive.

+

+It is mainly intended to provide compatibility with the Slackware

+installation scripts.

+

 @opsummary{keep-newer-files}

 @item --keep-newer-files

diff --git a/src/common.h b/src/common.h

index 16ba401..274da01 100644

--- a/src/common.h

+++ b/src/common.h

@@ -192,6 +192,8 @@ enum old_files

 };

 GLOBAL enum old_files old_files_option;

+GLOBAL bool keep_directory_symlink_option;

+

 /* Specified file name for incremental list.  */

 GLOBAL const char *listed_incremental_option;

 /* Incremental dump level */

diff --git a/src/extract.c b/src/extract.c

index 3afb95d..b622a2a 100644

--- a/src/extract.c

+++ b/src/extract.c

@@ -854,7 +854,21 @@ apply_nonancestor_delayed_set_stat (char const *file_name, bool after_links)

 }

+static bool

+is_directory_link (const char *file_name)

+{

+  struct stat st;

+  int e = errno;

+  int res;

+  res = (fstatat (chdir_fd, file_name, &st, AT_SYMLINK_NOFOLLOW) == 0 &&

+	 S_ISLNK (st.st_mode) &&

+	 fstatat (chdir_fd, file_name, &st, 0) == 0 &&

+	 S_ISDIR (st.st_mode));

+  errno = e;

+  return res;

+}

+

 /* Extractor functions for various member types */

 static int

@@ -910,10 +924,15 @@ extract_dir (char *file_name, int typeflag)

       if (errno == EEXIST

 	  && (interdir_made

+	      || keep_directory_symlink_option

 	      || old_files_option == DEFAULT_OLD_FILES

 	      || old_files_option == OVERWRITE_OLD_FILES))

 	{

 	  struct stat st;

+

+	  if (keep_directory_symlink_option && is_directory_link (file_name))

+	    return 0;

+

 	  if (deref_stat (file_name, &st) == 0)

 	    {

 	      current_mode = st.st_mode;

diff --git a/src/tar.c b/src/tar.c

index 18277e4..d62ca0e 100644

--- a/src/tar.c

+++ b/src/tar.c

@@ -290,6 +290,7 @@ enum

   IGNORE_COMMAND_ERROR_OPTION,

   IGNORE_FAILED_READ_OPTION,

   INDEX_FILE_OPTION,

+  KEEP_DIRECTORY_SYMLINK_OPTION,

   KEEP_NEWER_FILES_OPTION,

   LEVEL_OPTION,

   LZIP_OPTION,

@@ -488,6 +489,9 @@ static struct argp_option options[] = {

   {"overwrite-dir", OVERWRITE_DIR_OPTION, 0, 0,

    N_("overwrite metadata of existing directories when extracting (default)"),

    GRID+1 },

+  {"keep-directory-symlink", KEEP_DIRECTORY_SYMLINK_OPTION, 0, 0,

+   N_("preserve existing symlinks to directories when extracting"),

+   GRID+1 },

 #undef GRID

 #define GRID 40

@@ -1878,6 +1882,10 @@ parse_opt (int key, char *arg, struct argp_state *state)

       ignore_failed_read_option = true;

       break;

+    case KEEP_DIRECTORY_SYMLINK_OPTION:

+      keep_directory_symlink_option = true;

+      break;

+

     case KEEP_NEWER_FILES_OPTION:

       old_files_option = KEEP_NEWER_FILES;

       break;

-- 

2.9.3