sparse: fix pax extraction for unicode filenames

Make sure that 'GNU.sparse.name' header has higher priority than
(for sparse-purposes artificially modified) 'path' pax header.

Historically, the 'GNU.sparse.name' header comes before 'path';
this caused that modified 'path' header won and that is not what
we want in sparse "capable" tar implementation.

* src/tar.h (tar_stat_info): New argument sparse_name_done.
* src/xheader.c (raw_path_decoder): Move here the unconditional
code from path_decoder.
(path_decoder): Apply raw_path_decoder only if sparse_path_decoder
was not yet called.
(sparse_path_decoder): New wrapper around raw_path_decoder.
* tests/sparse07.at: New testcase.
* tests/testsuite.at: Mention new testcase.
* tests/Makefile.am: Likewise.

src/tar.h

@@ -331,6 +331,10 @@ struct tar_stat_info
   int   real_size_set;      /* True when GNU.sparse.realsize is set in
 			       archived file */
 
+  bool  sparse_name_done;   /* Set to true if 'GNU.sparse.name' header was
+                               processed pax header parsing.  Following 'path'
+                               header (lower priority) will be ignored. */
+
   size_t xattr_map_size;   /* Size of the xattr map */
   struct xattr_array *xattr_map;
 

src/xheader.c

@@ -1290,15 +1290,33 @@ path_coder (struct tar_stat_info const *st, char const *keyword,
   code_string (st->file_name, keyword, xhdr);
 }
 
+static void
+raw_path_decoder (struct tar_stat_info *st, char const *arg)
+{
+  decode_string (&st->orig_file_name, arg);
+  decode_string (&st->file_name, arg);
+  st->had_trailing_slash = strip_trailing_slashes (st->file_name);
+}
+
+
 static void
 path_decoder (struct tar_stat_info *st,
 	      char const *keyword __attribute__((unused)),
 	      char const *arg,
 	      size_t size __attribute__((unused)))
 {
-  decode_string (&st->orig_file_name, arg);
-  decode_string (&st->file_name, arg);
-  st->had_trailing_slash = strip_trailing_slashes (st->file_name);
+  if (! st->sparse_name_done)
+    raw_path_decoder (st, arg);
+}
+
+static void
+sparse_path_decoder (struct tar_stat_info *st,
+                     char const *keyword __attribute__((unused)),
+                     char const *arg,
+                     size_t size __attribute__((unused)))
+{
+  st->sparse_name_done = true;
+  raw_path_decoder (st, arg);
 }
 
 static void
@@ -1730,7 +1748,7 @@ struct xhdr_tab const xhdr_tab[] = {
   { "uname",    uname_coder,    uname_decoder,    0, false },
 
   /* Sparse file handling */
-  { "GNU.sparse.name",       path_coder, path_decoder,
+  { "GNU.sparse.name",       path_coder, sparse_path_decoder,
     XHDR_PROTECTED, false },
   { "GNU.sparse.major",      sparse_major_coder, sparse_major_decoder,
     XHDR_PROTECTED, false },

tests/Makefile.am

@@ -215,6 +215,7 @@ TESTSUITE_AT = \
  sparse04.at\
  sparse05.at\
  sparse06.at\
+ sparse07.at\
  sparsemv.at\
  sparsemvp.at\
  spmvp00.at\

tests/sparse07.at

@@ -0,0 +1,35 @@
+# Process this file with autom4te to create testsuite. -*- Autotest -*-
+
+# Test suite for GNU tar.
+# Copyright 2016 Free Software Foundation, Inc.
+
+# This file is part of GNU tar.
+
+# GNU tar 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 of the License, or
+# (at your option) any later version.
+
+# GNU tar 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/>.
+
+AT_SETUP([sparse files with unicode names])
+AT_KEYWORDS([sparse sparse07 unicode])
+
+AT_TAR_CHECK([
+genfile --sparse --file žluť --block-size 512 0 ABCD 1M EFGH 2000K IJKL || AT_SKIP_TEST
+tar -c -f archive --sparse žluť || exit 1
+
+tar tf archive
+],
+[0],
+[\305\276lu\305\245
+],
+[],[],[],[posix, gnu, oldgnu])
+
+AT_CLEANUP

tests/testsuite.at

@@ -387,6 +387,7 @@ m4_include([sparse03.at])
 m4_include([sparse04.at])
 m4_include([sparse05.at])
 m4_include([sparse06.at])
+m4_include([sparse07.at])
 m4_include([sparsemv.at])
 m4_include([spmvp00.at])
 m4_include([spmvp01.at])