cp/mv: add xattr support

This patch was originally written by Andreas Grünbacher, nowadays
available at
http://www.suse.de/~agruen/coreutils/5.91/coreutils-xattr.diff

* bootstrap.conf: Add gnulib module verror.
* po/POTFILES.in: Add lib/verror.c.
* m4/xattr.m4: Check for libattr availability, new configure option
--disable-xattr.
* m4/prereq.m4: Require gl_FUNC_XATTR.
* src/Makefile.am: Link cp, mv and ginstall with libattr.
* src/copy.h: Add preserve_xattr and require_preserve_xattr to
cp_options.
* src/copy.c (copy_attr_error): New function to handle errors during
xattr copying.
(copy_attr_quote): New function to quote file name in error messages
printed by libattr.
(copy_attr_free): Empty function requested by libattr to free quoted
string.
(copy_attr_by_fd): New fd-oriented function to copy xattr.
(copy_attr_by_name): New name-oriented function to copy xattr.
(copy_reg, copy_internal): Call copy_extended_attributes function.
* src/cp.c (usage): Mention new --preserve=xattr option.
(decode_preserve_arg): Handle new --preserve=xattr option.
* src/mv.c: Always attempt to preserve xattr.
* src/install.c: Never attempt to preserve xattr.
* tests/misc/xattr: New test for xattr support in cp, mv and install.
* tests/Makefile.am: Add the new test to list.
* doc/coreutils.texi: Mention xattr support, new --preserve=xattr
option.
* NEWS: Mention the change.

NEWS

@@ -4,6 +4,12 @@ GNU coreutils NEWS                                    -*- outline -*-
 
 ** New features
 
+  Add extended attribute support available on certain filesystems like ext2
+  and XFS.
+    cp: Tries to copy xattrs when --preserve=xattr specified
+    mv: Always tries to copy xattrs
+    install: Never copies xattrs
+
   cp and mv accept a new option, --no-clobber (-n): silently refrain
   from overwriting any existing destination file
 

bootstrap.conf

@@ -102,7 +102,7 @@ gnulib_modules="
 	userspec utimecmp utimens
 	vasprintf-posix
 	vc-list-files
-	verify version-etc-fsf
+	verify version-etc-fsf verror
 	warnings
 	wcwidth winsz-ioctl winsz-termios write-any-file
 	xalloc

doc/coreutils.texi

@@ -7365,7 +7365,7 @@ symbolic links in the destination are always followed if possible.
 @itemx @w{@kbd{--preserve}[=@var{attribute_list}]}
 @opindex -p
 @opindex --preserve
-@cindex file information, preserving
+@cindex file information, preserving, extended attributes, xattr
 Preserve the specified attributes of the original files.
 If specified, the @var{attribute_list} must be a comma-separated list
 of one or more of the following strings:
@@ -7392,6 +7392,11 @@ Preserve in the destination files
 any links between corresponding source files.
 @c Give examples illustrating how hard links are preserved.
 @c Also, show how soft links map to hard links with -L and -H.
+@itemx xattr
+Preserve extended attributes if @command{cp} is built with xattr support,
+and xattrs are supported and enabled on your file system.
+If SELinux context and/or ACLs are implemented using xattrs,
+they are preserved by this option as well.
 @itemx all
 Preserve all file attributes.
 Equivalent to specifying all of the above.
@@ -7935,6 +7940,9 @@ attributes of destination files.  It is typically used in Makefiles to
 copy programs into their destination directories.  It refuses to copy
 files onto themselves.
 
+@cindex extended attributes, xattr
+@command{install} never preserves extended attributes (xattr).
+
 The program accepts the following options.  Also see @ref{Common options}.
 
 @table @samp
@@ -8083,6 +8091,9 @@ directory succeeded, but the second didn't, the first would be left on
 the destination partition and the second and third would be left on the
 original partition.
 
+@cindex extended attributes, xattr
+@command{mv} always tries to copy extended attributes (xattr).
+
 @cindex prompting, and @command{mv}
 If a destination file exists but is normally unwritable, standard input
 is a terminal, and the @option{-f} or @option{--force} option is not given,

m4/prereq.m4

@@ -38,6 +38,7 @@ AC_DEFUN([gl_PREREQ],
   # handles that; see ../bootstrap.conf.
   AC_REQUIRE([gl_EUIDACCESS_STAT])
   AC_REQUIRE([gl_FD_REOPEN])
+  AC_REQUIRE([gl_FUNC_XATTR])
   AC_REQUIRE([gl_FUNC_XFTS])
   AC_REQUIRE([gl_MEMXFRM])
   AC_REQUIRE([gl_STRINTCMP])

m4/xattr.m4

@@ -0,0 +1,36 @@
+# xattr.m4 - check for Extended Attributes (Linux)
+
+# Copyright (C) 2003, 2008 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Originally written by Andreas Gruenbacher.
+# http://www.suse.de/~agruen/coreutils/5.91/coreutils-xattr.diff
+
+AC_DEFUN([gl_FUNC_XATTR],
+[
+  AC_ARG_ENABLE([xattr],
+	AC_HELP_STRING([--disable-xattr],
+		       [do not support extended attributes]),
+	[use_xattr=$enableval], [use_xattr=yes])
+
+  if test "$use_xattr" = "yes"; then
+    AC_CHECK_HEADERS([attr/error_context.h attr/libattr.h])
+    if test $ac_cv_header_attr_libattr_h = yes \
+       && test $ac_cv_header_attr_error_context_h = yes; then
+      use_xattr=1
+    else
+      use_xattr=0
+    fi
+    AC_DEFINE_UNQUOTED([USE_XATTR], [$use_xattr],
+		       [Define if you want extended attribute support.])
+    xattr_saved_LIBS=$LIBS
+    AC_SEARCH_LIBS([attr_copy_file], [attr],
+		   [test "$ac_cv_search_attr_copy_file" = "none required" ||
+		      LIB_XATTR=$ac_cv_search_attr_copy_file])
+    AC_CHECK_FUNCS([attr_copy_file])
+    LIBS=$xattr_saved_LIBS
+    AC_SUBST([LIB_XATTR])
+  fi
+])

po/POTFILES.in

@@ -1,5 +1,5 @@
 # List of files which contain translatable strings.
-# Copyright (C) 1996-2008 Free Software Foundation, Inc.
+# Copyright (C) 1996-2009 Free Software Foundation, Inc.
 
 # These are nominally temporary...
 lib/argmatch.c
@@ -22,6 +22,7 @@ lib/rpmatch.c
 lib/set-mode-acl.c
 lib/unicodeio.c
 lib/userspec.c
+lib/verror.c
 lib/version-etc.c
 lib/xalloc-die.c
 lib/xfreopen.c

src/Makefile.am

@@ -152,9 +152,9 @@ su_LDADD = $(LDADD) $(LIB_CRYPT)
 dir_LDADD += $(LIB_ACL)
 ls_LDADD += $(LIB_ACL)
 vdir_LDADD += $(LIB_ACL)
-cp_LDADD += $(LIB_ACL)
-mv_LDADD += $(LIB_ACL)
-ginstall_LDADD += $(LIB_ACL)
+cp_LDADD += $(LIB_ACL) $(LIB_XATTR)
+mv_LDADD += $(LIB_ACL) $(LIB_XATTR)
+ginstall_LDADD += $(LIB_ACL) $(LIB_XATTR)
 
 stat_LDADD = $(LDADD) $(LIB_SELINUX)
 

src/copy.c

@@ -1,5 +1,5 @@
 /* copy.c -- core functions for copying files and directories
-   Copyright (C) 89, 90, 91, 1995-2008 Free Software Foundation, Inc.
+   Copyright (C) 89, 90, 91, 1995-2009 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
@@ -54,6 +54,13 @@
 #include "areadlink.h"
 #include "yesno.h"
 
+#if USE_XATTR
+# include <attr/error_context.h>
+# include <attr/libattr.h>
+# include <stdarg.h>
+# include "verror.h"
+#endif
+
 #ifndef HAVE_FCHOWN
 # define HAVE_FCHOWN false
 # define fchown(fd, uid, gid) (-1)
@@ -123,6 +130,72 @@ is_ancestor (const struct stat *sb, const struct dir_list *ancestors)
   return false;
 }
 
+#if USE_XATTR
+static void
+copy_attr_error (struct error_context *ctx ATTRIBUTE_UNUSED,
+		 char const *fmt, ...)
+{
+  int err = errno;
+  va_list ap;
+
+  /* use verror module to print error message */
+  va_start (ap, fmt);
+  verror (0, err, fmt, ap);
+  va_end (ap);
+}
+
+static char const *
+copy_attr_quote (struct error_context *ctx ATTRIBUTE_UNUSED, char const *str)
+{
+  return quote (str);
+}
+
+static void
+copy_attr_free (struct error_context *ctx ATTRIBUTE_UNUSED,
+		char const *str ATTRIBUTE_UNUSED)
+{
+}
+
+static bool
+copy_attr_by_fd (char const *src_path, int src_fd,
+		 char const *dst_path, int dst_fd)
+{
+  struct error_context ctx =
+  {
+    .error = copy_attr_error,
+    .quote = copy_attr_quote,
+    .quote_free = copy_attr_free
+  };
+  return 0 == attr_copy_fd (src_path, src_fd, dst_path, dst_fd, 0, &ctx);
+}
+
+static bool
+copy_attr_by_name (char const *src_path, char const *dst_path)
+{
+  struct error_context ctx =
+  {
+    .error = copy_attr_error,
+    .quote = copy_attr_quote,
+    .quote_free = copy_attr_free
+  };
+  return 0 == attr_copy_file (src_path, dst_path, 0, &ctx);
+}
+#else /* USE_XATTR */
+
+static bool
+copy_attr_by_fd (char const *src_path, int src_fd,
+		 char const *dst_path, int dst_fd)
+{
+  return true;
+}
+
+static bool
+copy_attr_by_name (char const *src_path, char const *dst_path)
+{
+  return true;
+}
+#endif /* USE_XATTR */
+
 /* Read the contents of the directory SRC_NAME_IN, and recursively
    copy the contents to DST_NAME_IN.  NEW_DST is true if
    DST_NAME_IN is a directory that was created previously in the
@@ -681,6 +754,11 @@ copy_reg (char const *src_name, char const *dst_name,
 
   set_author (dst_name, dest_desc, src_sb);
 
+  if (x->preserve_xattr && ! copy_attr_by_fd (src_name, source_desc,
+					      dst_name, dest_desc)
+      && x->require_preserve_xattr)
+    return false;
+
   if (x->preserve_mode || x->move_mode)
     {
       if (copy_acl (src_name, source_desc, dst_name, dest_desc, src_mode) != 0
@@ -1985,6 +2063,10 @@ copy_internal (char const *src_name, char const *dst_name,
 
   set_author (dst_name, -1, &src_sb);
 
+  if (x->preserve_xattr && ! copy_attr_by_name (src_name, dst_name)
+      && x->require_preserve_xattr)
+    return false;
+
   if (x->preserve_mode || x->move_mode)
     {
       if (copy_acl (src_name, -1, dst_name, -1, src_mode) != 0

src/copy.h

@@ -173,6 +173,19 @@ struct cp_options
      fail if it is unable to do so.  */
   bool require_preserve_context;
 
+  /* If true, attempt to preserve extended attributes using libattr.
+     Ignored if coreutils are compiled without xattr support. */
+  bool preserve_xattr;
+
+  /* Useful only when preserve_xattr is true.
+     If true, a failed attempt to preserve file's extended attributes
+     propagates failure "out" to the caller.  If false, a failure to
+     preserve file's extended attributes does not change the invoking
+     application's exit status.  Give diagnostics for failed syscalls
+     regardless of this setting.  For example, with "cp --preserve=xattr"
+     this flag is "true", while with "cp --preserve=all", it is false. */
+  bool require_preserve_xattr;
+
   /* If true, copy directories recursively and copy special files
      as themselves rather than copying their contents. */
   bool recursive;

src/cp.c

@@ -187,7 +187,8 @@ Mandatory arguments to long options are mandatory for short options too.\n\
   -p                           same as --preserve=mode,ownership,timestamps\n\
       --preserve[=ATTR_LIST]   preserve the specified attributes (default:\n\
                                  mode,ownership,timestamps), if possible\n\
-                                 additional attributes: context, links, all\n\
+                                 additional attributes: context, links, xattr,\n\
+                                 all\n\
 "), stdout);
       fputs (_("\
       --no-preserve=ATTR_LIST  don't preserve the specified attributes\n\
@@ -764,6 +765,8 @@ cp_option_init (struct cp_options *x)
   x->preserve_timestamps = false;
   x->preserve_security_context = false;
   x->require_preserve_context = false;
+  x->preserve_xattr = false;
+  x->require_preserve_xattr = false;
 
   x->require_preserve = false;
   x->recursive = false;
@@ -800,18 +803,20 @@ decode_preserve_arg (char const *arg, struct cp_options *x, bool on_off)
       PRESERVE_OWNERSHIP,
       PRESERVE_LINK,
       PRESERVE_CONTEXT,
+      PRESERVE_XATTR,
       PRESERVE_ALL
     };
   static enum File_attribute const preserve_vals[] =
     {
       PRESERVE_MODE, PRESERVE_TIMESTAMPS,
-      PRESERVE_OWNERSHIP, PRESERVE_LINK, PRESERVE_CONTEXT, PRESERVE_ALL
+      PRESERVE_OWNERSHIP, PRESERVE_LINK, PRESERVE_CONTEXT, PRESERVE_XATTR,
+      PRESERVE_ALL
     };
   /* Valid arguments to the `--preserve' option. */
   static char const* const preserve_args[] =
     {
       "mode", "timestamps",
-      "ownership", "links", "context", "all", NULL
+      "ownership", "links", "context", "xattr", "all", NULL
     };
   ARGMATCH_VERIFY (preserve_args, preserve_vals);
 
@@ -852,6 +857,11 @@ decode_preserve_arg (char const *arg, struct cp_options *x, bool on_off)
 	  x->require_preserve_context = on_off;
 	  break;
 
+	case PRESERVE_XATTR:
+	  x->preserve_xattr = on_off;
+	  x->require_preserve_xattr = on_off;
+	  break;
+
 	case PRESERVE_ALL:
 	  x->preserve_mode = on_off;
 	  x->preserve_timestamps = on_off;
@@ -859,6 +869,7 @@ decode_preserve_arg (char const *arg, struct cp_options *x, bool on_off)
 	  x->preserve_links = on_off;
 	  if (selinux_enabled)
 	    x->preserve_security_context = on_off;
+	  x->preserve_xattr = on_off;
 	  break;
 
 	default:
@@ -1099,6 +1110,12 @@ main (int argc, char **argv)
 		 "without an SELinux-enabled kernel"));
     }
 
+#if !USE_XATTR
+  if (x.require_preserve_xattr)
+    error (EXIT_FAILURE, 0, _("cannot preserve extended attributes, cp is "
+			      "built without xattr support"));
+#endif
+
   /* Allocate space for remembering copied and created files.  */
 
   hash_init ();

src/install.c

@@ -200,6 +200,7 @@ cp_option_init (struct cp_options *x)
   x->open_dangling_dest_symlink = false;
   x->update = false;
   x->preserve_security_context = false;
+  x->preserve_xattr = false;
   x->verbose = false;
   x->dest_info = NULL;
   x->src_info = NULL;

src/mv.c

@@ -124,6 +124,7 @@ cp_option_init (struct cp_options *x)
   x->preserve_security_context = selinux_enabled;
   x->require_preserve = false;  /* FIXME: maybe make this an option */
   x->require_preserve_context = false;
+  x->preserve_xattr = true;
   x->recursive = true;
   x->sparse_mode = SPARSE_AUTO;  /* FIXME: maybe make this an option */
   x->symbolic_link = false;

tests/Makefile.am

@@ -234,6 +234,7 @@ TESTS =						\
   misc/tty-eof					\
   misc/unexpand					\
   misc/uniq					\
+  misc/xattr					\
   chmod/c-option				\
   chmod/equal-x					\
   chmod/equals					\

tests/misc/xattr

@@ -0,0 +1,111 @@
+#!/bin/sh
+# Ensure that cp --preserve=xattr and mv preserve extended attributes and
+# install does not preserve extended attributes.
+
+# Copyright (C) 2009 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 of the License, 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/>.
+
+if test "$VERBOSE" = yes; then
+  set -x
+  cp --version
+  mv --version
+  ginstall --version
+fi
+
+. $srcdir/test-lib.sh
+
+# Skip this test if cp was built without xattr support:
+touch src dest || framework_failure
+cp --preserve=xattr -n src dest 2>/dev/null \
+  || skip_test_ "coreutils built without xattr support"
+
+# this code was taken from test mv/backup-is-src
+cleanup_() { rm -rf "$other_partition_tmpdir"; }
+. "$abs_srcdir/other-fs-tmpdir"
+b_other="$other_partition_tmpdir/b"
+rm -f $b_other || framework_failure
+
+# testing xattr name-value pair
+xattr_name="user.foo"
+xattr_value="bar"
+xattr_pair="$xattr_name=\"$xattr_value\""
+
+# create new file and check its xattrs
+touch a || framework_failure
+getfattr -d a >out_a || skip_test_ "failed to get xattr of file"
+grep -F "$xattr_pair" out_a >/dev/null && framework_failure
+
+# try to set user xattr on file
+setfattr -n "$xattr_name" -v "$xattr_value" a >out_a \
+  || skip_test_ "failed to set xattr of file"
+getfattr -d a >out_a || skip_test_ "failed to get xattr of file"
+grep -F "$xattr_pair" out_a >/dev/null \
+  || skip_test_ "failed to set xattr of file"
+
+fail=0
+
+# cp should not preserve xattr by default
+cp a b || fail=1
+getfattr -d b >out_b || skip_test_ "failed to get xattr of file"
+grep -F "$xattr_pair" out_b >/dev/null && fail=1
+
+# test if --preserve=xattr option works
+cp --preserve=xattr a b || fail=1
+getfattr -d b >out_b || skip_test_ "failed to get xattr of file"
+grep -F "$xattr_pair" out_b >/dev/null || fail=1
+
+rm b || framework_failure
+
+# install should never preserve xattr
+ginstall a b || fail=1
+getfattr -d b >out_b || skip_test_ "failed to get xattr of file"
+grep -F "$xattr_pair" out_b >/dev/null && fail=1
+
+# mv should preserve xattr when renaming within a file system.
+# This is implicitly done by rename () and doesn't need explicit
+# xattr support in mv.
+mv a b || fail=1
+getfattr -d b >out_b || skip_test_ "failed to get xattr of file"
+grep -F "$xattr_pair" out_b >/dev/null || cat >&2 <<EOF
+=================================================================
+$0: WARNING!!!
+rename () does not preserve extended attributes
+=================================================================
+EOF
+
+# try to set user xattr on file on other partition
+test_mv=1
+touch $b_other || framework_failure
+setfattr -n "$xattr_name" -v "$xattr_value" $b_other >out_a 2>/dev/null \
+  || test_mv=0
+getfattr -d $b_other >out_b 2>/dev/null || test_mv=0
+grep -F "$xattr_pair" out_b >/dev/null || test_mv=0
+rm -f $b_other || framework_failure
+
+if test $test_mv -eq 1; then
+  # mv should preserve xattr when copying content from one partition to another
+  mv b $b_other || fail=1
+  getfattr -d $b_other >out_b 2>/dev/null || skip_test_ "failed to get xattr of file"
+  grep -F "$xattr_pair" out_b >/dev/null || fail=1
+else
+  cat >&2 <<EOF
+=================================================================
+$0: WARNING!!!
+failed to set xattr of file $b_other
+=================================================================
+EOF
+fi
+
+Exit $fail