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.

6 files changed, 121 insertions, 7 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 555700bad..907b9e799 100644
--- a/src/Makefile.am
+++ b/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)
 
diff --git a/src/copy.c b/src/copy.c
index c9c79a1b1..85d1fea13 100644
--- a/src/copy.c
+++ b/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
diff --git a/src/copy.h b/src/copy.h
index 12b7c2d28..e6604ee71 100644
--- a/src/copy.h
+++ b/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;
diff --git a/src/cp.c b/src/cp.c
index 191f73e7b..9171fa652 100644
--- a/src/cp.c
+++ b/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 ();
diff --git a/src/install.c b/src/install.c
index 9dda05ade..9bf9eee0f 100644
--- a/src/install.c
+++ b/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;
diff --git a/src/mv.c b/src/mv.c
index a5ab95dcf..db9207bd5 100644
--- a/src/mv.c
+++ b/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;