In get_xattr_data(): replace the input value of *len_ptr with its

[rsync/rsync-patches.git] / xattrs.diff

This patch adds support for extended attributes.

To use this patch, run these commands for a successful build:

    patch -p1 <patches/xattrs.diff
    ./prepare-source
    ./configure
    make

CAUTION:  this patch has been recently reworked, and needs more testing!

TODO:

 - When an xattr value is long enough to be checksummed and is not changed,
   we need to have the receiver get the unchanged value from the receiving
   side instead of requesting that it be sent from the sender.

--- old/Makefile.in
+++ new/Makefile.in
@@ -28,13 +28,13 @@ VERSION=@VERSION@
 
 HEADERS=byteorder.h config.h errcode.h proto.h rsync.h smb_acls.h lib/pool_alloc.h
 LIBOBJ=lib/wildmatch.o lib/compat.o lib/snprintf.o lib/mdfour.o lib/md5.o \
-	lib/permstring.o lib/pool_alloc.o lib/sysacls.o @LIBOBJS@
+	lib/permstring.o lib/pool_alloc.o lib/sysacls.o lib/sysxattrs.o @LIBOBJS@
 ZLIBOBJ=zlib/deflate.o zlib/inffast.o zlib/inflate.o zlib/inftrees.o \
 	zlib/trees.o zlib/zutil.o zlib/adler32.o zlib/compress.o zlib/crc32.o
 OBJS1=flist.o rsync.o generator.o receiver.o cleanup.o sender.o exclude.o \
 	util.o main.o checksum.o match.o syscall.o log.o backup.o
 OBJS2=options.o io.o compat.o hlink.o token.o uidlist.o socket.o \
-	fileio.o batch.o clientname.o chmod.o acls.o
+	fileio.o batch.o clientname.o chmod.o acls.o xattrs.o
 OBJS3=progress.o pipe.o
 DAEMON_OBJ = params.o loadparm.o clientserver.o access.o connection.o authenticate.o
 popt_OBJS=popt/findme.o  popt/popt.o  popt/poptconfig.o \
--- old/backup.c
+++ new/backup.c
@@ -23,6 +23,7 @@
 extern int verbose;
 extern int am_root;
 extern int preserve_acls;
+extern int preserve_xattrs;
 extern int preserve_devices;
 extern int preserve_specials;
 extern int preserve_links;
@@ -134,6 +135,9 @@ static int make_bak_dir(char *fullpath)
 #ifdef SUPPORT_ACLS
 				sx.acc_acl = sx.def_acl = NULL;
 #endif
+#ifdef SUPPORT_XATTRS
+				sx.xattr = NULL;
+#endif
 				if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
 					continue;
 #ifdef SUPPORT_ACLS
@@ -143,6 +147,13 @@ static int make_bak_dir(char *fullpath)
 					free_acl(&sx);
 				}
 #endif
+#ifdef SUPPORT_XATTRS
+				if (preserve_xattrs) {
+					get_xattr(rel, &sx);
+					cache_xattr(file, &sx);
+					free_xattr(&sx);
+				}
+#endif
 				set_file_attrs(fullpath, file, NULL, 0);
 				free(file);
 			}
@@ -194,6 +205,9 @@ static int keep_backup(const char *fname
 #ifdef SUPPORT_ACLS
 	sx.acc_acl = sx.def_acl = NULL;
 #endif
+#ifdef SUPPORT_XATTRS
+	sx.xattr = NULL;
+#endif
 
 	if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 		return 1; /* the file could have disappeared */
@@ -210,6 +224,13 @@ static int keep_backup(const char *fname
 		free_acl(&sx);
 	}
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs) {
+		get_xattr(fname, &sx);
+		cache_xattr(file, &sx);
+		free_xattr(&sx);
+	}
+#endif
 
 	/* Check to see if this is a device file, or link */
 	if ((am_root && preserve_devices && IS_DEVICE(file->mode))
--- old/compat.c
+++ new/compat.c
@@ -43,6 +43,7 @@ extern int protocol_version;
 extern int preserve_uid;
 extern int preserve_gid;
 extern int preserve_acls;
+extern int preserve_xattrs;
 extern int preserve_hard_links;
 extern int need_messages_from_generator;
 extern int delete_mode, delete_before, delete_during, delete_after;
@@ -65,6 +66,8 @@ void setup_protocol(int f_out,int f_in)
 		preserve_gid = ++file_extra_cnt;
 	if (preserve_acls && !am_sender)
 		preserve_acls = ++file_extra_cnt;
+	if (preserve_xattrs)
+		preserve_xattrs = ++file_extra_cnt;
 
 	if (remote_protocol == 0) {
 		if (!read_batch)
@@ -119,6 +122,13 @@ void setup_protocol(int f_out,int f_in)
 			    protocol_version);
 			exit_cleanup(RERR_PROTOCOL);
 		}
+		if (preserve_xattrs) {
+			rprintf(FERROR,
+			    "--xattrs requires protocol 30 or higher"
+			    " (negotiated %d).\n",
+			    protocol_version);
+			exit_cleanup(RERR_PROTOCOL);
+		}
 	}
 
 	if (delete_mode && !(delete_before+delete_during+delete_after)) {
--- old/configure.in
+++ new/configure.in
@@ -891,6 +891,46 @@ samba_cv_HAVE_ACL_GET_PERM_NP=yes,samba_
     esac
 fi
 
+AC_CHECK_HEADERS(attr/xattr.h)
+AC_CHECK_HEADERS(sys/xattr.h)
+AC_CHECK_HEADERS(sys/extattr.h)
+
+#################################################
+# check for extended attribute support
+AC_MSG_CHECKING(whether to support extended attributes)
+AC_ARG_ENABLE(xattr-support,
+	AC_HELP_STRING([--disable-xattr-support],
+		       [Turn off extended attribute support]))
+
+if test x"$enable_xattr_support" = x"no"; then
+    AC_MSG_RESULT(no)
+else
+    case "$host_os" in
+    *linux*)
+	AC_MSG_RESULT(Using Linux xattrs)
+	AC_DEFINE(HAVE_LINUX_XATTRS, 1, [True if you have Linux xattrs])
+	AC_DEFINE(SUPPORT_XATTRS, 1, [Define to 1 to add support for extended attributes])
+	;;
+    darwin*)
+	AC_MSG_RESULT(Using OS X xattrs)
+	AC_DEFINE(HAVE_OSX_XATTRS, 1, [True if you have Mac OS X xattrs])
+	AC_DEFINE(SUPPORT_XATTRS, 1)
+	;;
+    freebsd*)
+	AC_MSG_RESULT(Using FreeBSD extattrs)
+	AC_DEFINE(HAVE_FREEBSD_XATTRS, 1, [True if you have FreeBSD xattrs])
+	AC_DEFINE(SUPPORT_XATTRS, 1)
+	;;
+    *)
+	if test x"$enable_xattr_support" = x"yes"; then
+	    AC_MSG_ERROR(Failed to find extended attribute support)
+	else
+	    AC_MSG_RESULT(No extended attribute support found)
+	fi
+	;;
+    esac
+fi
+
 AC_CONFIG_FILES([Makefile lib/dummy zlib/dummy popt/dummy shconfig])
 AC_OUTPUT
 
--- old/flist.c
+++ new/flist.c
@@ -43,6 +43,7 @@ extern int one_file_system;
 extern int copy_dirlinks;
 extern int keep_dirlinks;
 extern int preserve_acls;
+extern int preserve_xattrs;
 extern int preserve_links;
 extern int preserve_hard_links;
 extern int preserve_devices;
@@ -888,6 +889,10 @@ static struct file_struct *recv_file_ent
 	if (preserve_acls && !S_ISLNK(mode))
 		receive_acl(file, f);
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs)
+		receive_xattr(file, f );
+#endif
 
 	if (S_ISREG(mode) || S_ISLNK(mode))
 		stats.total_size += file_length;
@@ -1160,7 +1165,7 @@ static struct file_struct *send_file_nam
 					  int flags, int filter_flags)
 {
 	struct file_struct *file;
-#ifdef SUPPORT_ACLS
+#if defined SUPPORT_ACLS || defined SUPPORT_XATTRS
 	statx sx;
 #endif
 
@@ -1179,6 +1184,13 @@ static struct file_struct *send_file_nam
 			return NULL;
 	}
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs && f >= 0) {
+		sx.xattr = NULL;
+		if (get_xattr(fname, &sx) < 0)
+			return NULL;
+	}
+#endif
 
 	maybe_emit_filelist_progress(flist->count + flist_count_offset);
 
@@ -1192,6 +1204,12 @@ static struct file_struct *send_file_nam
 			free_acl(&sx);
 		}
 #endif
+#ifdef SUPPORT_XATTRS
+		if (preserve_xattrs) {
+			F_XATTR(file) = send_xattr(&sx, f);
+			free_xattr(&sx);
+		}
+#endif
 	}
 	return file;
 }
--- old/generator.c
+++ new/generator.c
@@ -36,6 +36,7 @@ extern int relative_paths;
 extern int implied_dirs;
 extern int keep_dirlinks;
 extern int preserve_acls;
+extern int preserve_xattrs;
 extern int preserve_links;
 extern int preserve_devices;
 extern int preserve_specials;
@@ -532,6 +533,14 @@ int unchanged_attrs(const char *fname, s
 			return 0;
 	}
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs) {
+		if (!XATTR_READY(*sxp))
+			get_xattr(fname, sxp);
+		if (xattr_diff(file, sxp, 0))
+			return 0;
+	}
+#endif
 
 	return 1;
 }
@@ -567,11 +576,19 @@ void itemize(const char *fname, struct f
 				iflags |= ITEM_REPORT_ACL;
 		}
 #endif
+#ifdef SUPPORT_XATTRS
+		if (preserve_xattrs) {
+			if (!XATTR_READY(*sxp))
+				get_xattr(fname, sxp);
+			if (xattr_diff(file, sxp, 1))
+				iflags |= ITEM_REPORT_XATTR;
+		}
+#endif
 	} else
 		iflags |= ITEM_IS_NEW;
 
 	iflags &= 0xffff;
-	if ((iflags & SIGNIFICANT_ITEM_FLAGS || verbose > 1
+	if ((iflags & (SIGNIFICANT_ITEM_FLAGS|ITEM_REPORT_XATTR) || verbose > 1
 	  || stdout_format_has_i > 1 || (xname && *xname)) && !read_batch) {
 		if (protocol_version >= 29) {
 			if (ndx >= 0)
@@ -581,6 +598,10 @@ void itemize(const char *fname, struct f
 				write_byte(sock_f_out, fnamecmp_type);
 			if (iflags & ITEM_XNAME_FOLLOWS)
 				write_vstring(sock_f_out, xname, strlen(xname));
+#ifdef SUPPORT_XATTRS
+			if (iflags & ITEM_REPORT_XATTR && !dry_run)
+				send_xattr_request(NULL, file, sock_f_out);
+#endif
 		} else if (ndx >= 0) {
 			enum logcode code = logfile_format_has_i ? FINFO : FCLIENT;
 			log_item(code, file, &stats, iflags, xname);
@@ -1112,6 +1133,9 @@ static void recv_generator(char *fname, 
 #ifdef SUPPORT_ACLS
 	sx.acc_acl = sx.def_acl = NULL;
 #endif
+#ifdef SUPPORT_XATTRS
+	sx.xattr = NULL;
+#endif
 	if (dry_run > 1) {
 		if (fuzzy_dirlist) {
 			flist_free(fuzzy_dirlist);
@@ -1636,6 +1660,10 @@ static void recv_generator(char *fname, 
 		if (preserve_acls)
 			free_acl(&real_sx);
 #endif
+#ifdef SUPPORT_XATTRS
+		if (preserve_xattrs)
+			free_xattr(&real_sx);
+#endif
 	}
 
 	if (!do_xfers) {
@@ -1672,6 +1700,10 @@ static void recv_generator(char *fname, 
 	if (preserve_acls)
 		free_acl(&sx);
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs)
+		free_xattr(&sx);
+#endif
 	return;
 }
 
--- old/lib/sysxattrs.c
+++ new/lib/sysxattrs.c
@@ -0,0 +1,135 @@
+/*
+ * Extended attribute support for rsync.
+ *
+ * Copyright (C) 2004 Red Hat, Inc.
+ * Written by Jay Fenlason.
+ *
+ * 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 2 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "rsync.h"
+#include "sysxattrs.h"
+
+#ifdef SUPPORT_XATTRS
+
+#if defined HAVE_LINUX_XATTRS
+
+ssize_t sys_lgetxattr(const char *path, const char *name, void *value, size_t size)
+{
+	return lgetxattr(path, name, value, size);
+}
+
+ssize_t sys_fgetxattr(int filedes, const char *name, void *value, size_t size)
+{
+	return fgetxattr(filedes, name, value, size);
+}
+
+int sys_lsetxattr(const char *path, const char *name, const void *value, size_t size)
+{
+	return lsetxattr(path, name, value, size, 0);
+}
+
+int sys_lremovexattr(const char *path, const char *name)
+{
+	return lremovexattr(path, name);
+}
+
+ssize_t sys_llistxattr(const char *path, char *list, size_t size)
+{
+	return llistxattr(path, list, size);
+}
+
+#elif HAVE_OSX_XATTRS
+
+ssize_t sys_lgetxattr(const char *path, const char *name, void *value, size_t size)
+{
+	return getxattr(path, name, value, size, 0, XATTR_NOFOLLOW);
+}
+
+ssize_t sys_fgetxattr(int filedes, const char *name, void *value, size_t size)
+{
+	return fgetxattr(filedes, name, value, size, 0, 0);
+}
+
+int sys_lsetxattr(const char *path, const char *name, const void *value, size_t size)
+{
+	return setxattr(path, name, value, size, 0, XATTR_NOFOLLOW);
+}
+
+int sys_lremovexattr(const char *path, const char *name)
+{
+	return removexattr(path, name, XATTR_NOFOLLOW);
+}
+
+ssize_t sys_llistxattr(const char *path, char *list, size_t size)
+{
+	return listxattr(path, list, size, XATTR_NOFOLLOW);
+}
+
+#elif HAVE_FREEBSD_XATTRS
+
+ssize_t sys_lgetxattr(const char *path, const char *name, void *value, size_t size)
+{
+	return extattr_get_link(path, EXTATTR_NAMESPACE_USER, name, value, size);
+}
+
+ssize_t sys_fgetxattr(int filedes, const char *name, void *value, size_t size)
+{
+	return extattr_get_fd(filedes, EXTATTR_NAMESPACE_USER, name, value, size);
+}
+
+int sys_lsetxattr(const char *path, const char *name, const void *value, size_t size)
+{
+	return extattr_set_link(path, EXTATTR_NAMESPACE_USER, name, value, size);
+}
+
+int sys_lremovexattr(const char *path, const char *name)
+{
+	return extattr_delete_link(path, EXTATTR_NAMESPACE_USER, name);
+}
+
+ssize_t sys_llistxattr(const char *path, char *list, size_t size)
+{
+	unsigned char keylen;
+	ssize_t off, len = extattr_list_link(path, EXTATTR_NAMESPACE_USER, list, size);
+
+	if (len <= 0 || (size_t)len > size)
+		return len;
+
+	/* FreeBSD puts a single-byte length before each string, with no '\0'
+	 * terminator.  We need to change this into a series of null-terminted
+	 * strings.  Since the size is the same, we can simply transform the
+	 * output in place. */
+	for (off = 0; off < len; off += keylen + 1) {
+		keylen = ((unsigned char*)list)[off];
+		if (off + keylen >= len) {
+			/* Should be impossible, but kernel bugs happen! */
+			errno = EINVAL;
+			return -1;
+		}
+		memmove(list+off, list+off+1, keylen);
+		list[off+keylen] = '\0';
+	}
+
+	return len;
+}
+
+#else
+
+#error You need to create xattr compatibility functions.
+
+#endif
+
+#endif /* SUPPORT_XATTRS */
--- old/lib/sysxattrs.h
+++ new/lib/sysxattrs.h
@@ -0,0 +1,26 @@
+#ifdef SUPPORT_XATTRS
+
+#if defined HAVE_ATTR_XATTR_H
+#include <attr/xattr.h>
+#elif defined HAVE_SYS_XATTR_H
+#include <sys/xattr.h>
+#elif defined HAVE_SYS_EXTATTR_H
+#include <sys/extattr.h>
+#endif
+
+/* Linux 2.4 does not define this as a distinct errno value: */
+#ifndef ENOATTR
+#define ENOATTR ENODATA
+#endif
+
+ssize_t sys_lgetxattr(const char *path, const char *name, void *value, size_t size);
+ssize_t sys_fgetxattr(int filedes, const char *name, void *value, size_t size);
+int sys_lsetxattr(const char *path, const char *name, const void *value, size_t size);
+int sys_lremovexattr(const char *path, const char *name);
+ssize_t sys_llistxattr(const char *path, char *list, size_t size);
+
+#else
+
+/* No xattrs available */
+
+#endif
--- old/main.c
+++ new/main.c
@@ -608,7 +608,7 @@ static void fix_basis_dirs(void)
 }
 
 /* This is only called by the sender. */
-static void read_final_goodbye(int f_in, int f_out)
+static void read_final_goodbye(int f_in)
 {
 	int i, iflags, xlen;
 	uchar fnamecmp_type;
@@ -617,8 +617,8 @@ static void read_final_goodbye(int f_in,
 	if (protocol_version < 29)
 		i = read_int(f_in);
 	else {
-		i = read_ndx_and_attrs(f_in, f_out, &iflags,
-				       &fnamecmp_type, xname, &xlen);
+		i = read_ndx_and_attrs(f_in, &iflags, &fnamecmp_type,
+				       xname, &xlen);
 	}
 
 	if (i != NDX_DONE) {
@@ -677,7 +677,7 @@ static void do_server_sender(int f_in, i
 	io_flush(FULL_FLUSH);
 	handle_stats(f_out);
 	if (protocol_version >= 24)
-		read_final_goodbye(f_in, f_out);
+		read_final_goodbye(f_in);
 	io_flush(FULL_FLUSH);
 	exit_cleanup(0);
 }
@@ -740,7 +740,7 @@ static int do_recv(int f_in, int f_out, 
 			kluge_around_eof = -1;
 
 			/* This should only get stopped via a USR2 signal. */
-			read_ndx_and_attrs(f_in, -1, &iflags, &fnamecmp_type,
+			read_ndx_and_attrs(f_in, &iflags, &fnamecmp_type,
 					   xname, &xlen);
 
 			rprintf(FERROR, "Invalid packet at end of run [%s]\n",
@@ -977,7 +977,7 @@ int client_run(int f_in, int f_out, pid_
 		io_flush(FULL_FLUSH);
 		handle_stats(-1);
 		if (protocol_version >= 24)
-			read_final_goodbye(f_in, f_out);
+			read_final_goodbye(f_in);
 		if (pid != -1) {
 			if (verbose > 3)
 				rprintf(FINFO,"client_run waiting on %d\n", (int) pid);
--- old/options.c
+++ new/options.c
@@ -47,6 +47,7 @@ int copy_links = 0;
 int preserve_links = 0;
 int preserve_hard_links = 0;
 int preserve_acls = 0;
+int preserve_xattrs = 0;
 int preserve_perms = 0;
 int preserve_executability = 0;
 int preserve_devices = 0;
@@ -201,6 +202,7 @@ static void print_rsync_version(enum log
 	char const *have_inplace = "no ";
 	char const *hardlinks = "no ";
 	char const *acls = "no ";
+	char const *xattrs = "no ";
 	char const *links = "no ";
 	char const *ipv6 = "no ";
 	STRUCT_STAT *dumstat;
@@ -220,7 +222,9 @@ static void print_rsync_version(enum log
 #ifdef SUPPORT_ACLS
 	acls = "";
 #endif
-
+#ifdef SUPPORT_XATTRS
+	xattrs = "";
+#endif
 #ifdef SUPPORT_LINKS
 	links = "";
 #endif
@@ -239,8 +243,8 @@ static void print_rsync_version(enum log
 		(int)(sizeof (int64) * 8));
 	rprintf(f, "    %ssocketpairs, %shardlinks, %ssymlinks, %sIPv6, batchfiles, %sinplace,\n",
 		got_socketpair, hardlinks, links, ipv6, have_inplace);
-	rprintf(f, "    %sappend, %sACLs\n",
-		have_inplace, acls);
+	rprintf(f, "    %sappend, %sACLs, %sxattrs\n",
+		have_inplace, acls, xattrs);
 
 #ifdef MAINTAINER_MODE
 	rprintf(f, "Panic Action: \"%s\"\n", get_panic_action());
@@ -286,7 +290,7 @@ void usage(enum logcode F)
   rprintf(F," -q, --quiet                 suppress non-error messages\n");
   rprintf(F,"     --no-motd               suppress daemon-mode MOTD (see manpage caveat)\n");
   rprintf(F," -c, --checksum              skip based on checksum, not mod-time & size\n");
-  rprintf(F," -a, --archive               archive mode; same as -rlptgoD (no -H, -A)\n");
+  rprintf(F," -a, --archive               archive mode; equals -rlptgoD (no -H,-A,-X)\n");
   rprintf(F,"     --no-OPTION             turn off an implied OPTION (e.g. --no-D)\n");
   rprintf(F," -r, --recursive             recurse into directories\n");
   rprintf(F," -R, --relative              use relative path names\n");
@@ -311,6 +315,9 @@ void usage(enum logcode F)
 #ifdef SUPPORT_ACLS
   rprintf(F," -A, --acls                  preserve ACLs (implies --perms)\n");
 #endif
+#ifdef SUPPORT_XATTRS
+  rprintf(F," -X, --xattrs                preserve extended attributes (implies --perms)\n");
+#endif
   rprintf(F," -o, --owner                 preserve owner (super-user only)\n");
   rprintf(F," -g, --group                 preserve group\n");
   rprintf(F,"     --devices               preserve device files (super-user only)\n");
@@ -438,6 +445,9 @@ static struct poptOption long_options[] 
   {"acls",            'A', POPT_ARG_NONE,   0, 'A', 0, 0 },
   {"no-acls",          0,  POPT_ARG_VAL,    &preserve_acls, 0, 0, 0 },
   {"no-A",             0,  POPT_ARG_VAL,    &preserve_acls, 0, 0, 0 },
+  {"xattrs",          'X', POPT_ARG_NONE,   0, 'X', 0, 0 },
+  {"no-xattrs",        0,  POPT_ARG_VAL,    &preserve_xattrs, 0, 0, 0 },
+  {"no-X",             0,  POPT_ARG_VAL,    &preserve_xattrs, 0, 0, 0 },
   {"times",           't', POPT_ARG_VAL,    &preserve_times, 1, 0, 0 },
   {"no-times",         0,  POPT_ARG_VAL,    &preserve_times, 0, 0, 0 },
   {"no-t",             0,  POPT_ARG_VAL,    &preserve_times, 0, 0, 0 },
@@ -1126,6 +1136,17 @@ int parse_arguments(int *argc, const cha
 			return 0;
 #endif
 
+		case 'X':
+#ifdef SUPPORT_XATTRS
+			preserve_xattrs = 1;
+			preserve_perms = 1;
+			break;
+#else
+			snprintf(err_buf,sizeof(err_buf),
+				 "extended attributes are not supported on this %s\n",
+				 am_server ? "server" : "client");
+			return 0;
+#endif
 
 		default:
 			/* A large opt value means that set_refuse_options()
@@ -1590,6 +1611,10 @@ void server_options(char **args,int *arg
 	if (preserve_acls)
 		argstr[x++] = 'A';
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs)
+		argstr[x++] = 'X';
+#endif
 	if (recurse)
 		argstr[x++] = 'r';
 	if (always_checksum)
--- old/receiver.c
+++ new/receiver.c
@@ -22,6 +22,7 @@
 #include "rsync.h"
 
 extern int verbose;
+extern int dry_run;
 extern int do_xfers;
 extern int am_server;
 extern int do_progress;
@@ -366,8 +367,8 @@ int recv_files(int f_in, char *local_nam
 		cleanup_disable();
 
 		/* This call also sets cur_flist. */
-		ndx = read_ndx_and_attrs(f_in, -1, &iflags,
-					 &fnamecmp_type, xname, &xlen);
+		ndx = read_ndx_and_attrs(f_in, &iflags, &fnamecmp_type,
+					 xname, &xlen);
 		if (ndx == NDX_DONE) {
 			if (inc_recurse && first_flist) {
 				flist_free(first_flist);
@@ -397,8 +398,17 @@ int recv_files(int f_in, char *local_nam
 		if (verbose > 2)
 			rprintf(FINFO, "recv_files(%s)\n", fname);
 
+#ifdef SUPPORT_XATTRS
+		if (iflags & ITEM_REPORT_XATTR && !dry_run)
+			recv_xattr_request(file, f_in);
+#endif
+
 		if (!(iflags & ITEM_TRANSFER)) {
 			maybe_log_item(file, iflags, itemizing, xname);
+#ifdef SUPPORT_XATTRS
+			if (iflags & ITEM_REPORT_XATTR && !dry_run)
+				set_file_attrs(fname, file, NULL, 0);
+#endif
 			continue;
 		}
 		if (phase == 2) {
--- old/rsync.c
+++ new/rsync.c
@@ -32,6 +32,7 @@
 extern int verbose;
 extern int dry_run;
 extern int preserve_acls;
+extern int preserve_xattrs;
 extern int preserve_perms;
 extern int preserve_executability;
 extern int preserve_times;
@@ -91,10 +92,8 @@ void setup_iconv()
 }
 #endif
 
-/* This is used by sender.c with a valid f_out, and by receive.c with
- * f_out = -1. */
-int read_ndx_and_attrs(int f_in, int f_out, int *iflag_ptr,
-		       uchar *type_ptr, char *buf, int *len_ptr)
+int read_ndx_and_attrs(int f_in, int *iflag_ptr, uchar *type_ptr,
+		       char *buf, int *len_ptr)
 {
 	int len, iflags = 0;
 	struct file_list *flist;
@@ -181,11 +180,6 @@ int read_ndx_and_attrs(int f_in, int f_o
 				ndx, who_am_i());
 			exit_cleanup(RERR_PROTOCOL);
 		}
-	} else if (f_out >= 0) {
-		if (inc_recurse)
-			send_extra_file_list(f_out, FILECNT_LOOKAHEAD);
-		write_ndx_and_attrs(f_out, ndx, iflags,
-				    fnamecmp_type, buf, len);
 	}
 
 	*iflag_ptr = iflags;
@@ -247,6 +241,9 @@ int set_file_attrs(char *fname, struct f
 #ifdef SUPPORT_ACLS
 		sx2.acc_acl = sx2.def_acl = NULL;
 #endif
+#ifdef SUPPORT_XATTRS
+		sx2.xattr = NULL;
+#endif
 		if (!preserve_perms && S_ISDIR(new_mode)
 		 && sx2.st.st_mode & S_ISGID) {
 			/* We just created this directory and its setgid
@@ -321,6 +318,10 @@ int set_file_attrs(char *fname, struct f
 	if (daemon_chmod_modes && !S_ISLNK(new_mode))
 		new_mode = tweak_mode(new_mode, daemon_chmod_modes);
 
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs && !am_generator)
+		set_xattr(fname, file, sxp);
+#endif
 #ifdef SUPPORT_ACLS
 	/* It's OK to call set_acl() now, even for a dir, as the generator
 	 * will enable owner-writability using chmod, if necessary.
@@ -353,10 +354,16 @@ int set_file_attrs(char *fname, struct f
 			rprintf(FCLIENT, "%s is uptodate\n", fname);
 	}
   cleanup:
+	if (sxp == &sx2) {
 #ifdef SUPPORT_ACLS
-	if (preserve_acls && sxp == &sx2)
-		free_acl(&sx2);
+		if (preserve_acls)
+			free_acl(&sx2);
 #endif
+#ifdef SUPPORT_XATTRS
+		if (preserve_xattrs)
+			free_xattr(&sx2);
+#endif
+	}
 	return updated;
 }
 
--- old/rsync.h
+++ new/rsync.h
@@ -569,6 +569,7 @@ extern int file_extra_cnt;
 extern int preserve_uid;
 extern int preserve_gid;
 extern int preserve_acls;
+extern int preserve_xattrs;
 
 #define FILE_STRUCT_LEN (offsetof(struct file_struct, basename))
 #define EXTRA_LEN (sizeof (union file_extras))
@@ -601,7 +602,8 @@ extern int preserve_acls;
 /* When the associated option is on, all entries will have these present: */
 #define F_OWNER(f) REQ_EXTRA(f, preserve_uid)->unum
 #define F_GROUP(f) REQ_EXTRA(f, preserve_gid)->unum
-#define F_ACL(f) REQ_EXTRA(f, preserve_acls)->unum
+#define F_ACL(f) REQ_EXTRA(f, preserve_acls)->num
+#define F_XATTR(f) REQ_EXTRA(f, preserve_xattrs)->num
 
 /* These items are per-entry optional and mutally exclusive: */
 #define F_HL_GNUM(f) OPT_EXTRA(f, LEN64_BUMP(f))->num
@@ -793,9 +795,13 @@ typedef struct {
     struct rsync_acl *acc_acl; /* access ACL */
     struct rsync_acl *def_acl; /* default ACL */
 #endif
+#ifdef SUPPORT_XATTRS
+    item_list *xattr;
+#endif
 } statx;
 
 #define ACL_READY(sx) ((sx).acc_acl != NULL)
+#define XATTR_READY(sx) ((sx).xattr != NULL)
 
 #include "proto.h"
 
--- old/rsync.yo
+++ new/rsync.yo
@@ -301,7 +301,7 @@ to the detailed description below for a 
  -q, --quiet                 suppress non-error messages
      --no-motd               suppress daemon-mode MOTD (see caveat)
  -c, --checksum              skip based on checksum, not mod-time & size
- -a, --archive               archive mode; same as -rlptgoD (no -H, -A)
+ -a, --archive               archive mode; equals -rlptgoD (no -H,-A,-X)
      --no-OPTION             turn off an implied OPTION (e.g. --no-D)
  -r, --recursive             recurse into directories
  -R, --relative              use relative path names
@@ -324,6 +324,7 @@ to the detailed description below for a 
  -E, --executability         preserve executability
      --chmod=CHMOD           affect file and/or directory permissions
  -A, --acls                  preserve ACLs (implies -p)
+ -X, --xattrs                preserve extended attrs (implies -p)
  -o, --owner                 preserve owner (super-user only)
  -g, --group                 preserve group
      --devices               preserve device files (super-user only)
@@ -831,6 +832,11 @@ dit(bf(-A, --acls)) This option causes r
 ACLs to be the same as the source ACLs.  This nonstandard option only
 works if the remote rsync also supports it.  bf(--acls) implies bf(--perms).
 
+dit(bf(-X, --xattrs)) This option causes rsync to update the remote
+extended attributes to be the same as the local ones.  This will work
+only if the remote machine's rsync supports this option also. This is
+a non-standard option.
+
 dit(bf(--chmod)) This option tells rsync to apply one or more
 comma-separated "chmod" strings to the permission of the files in the
 transfer.  The resulting value is treated as though it was the permissions
--- old/sender.c
+++ new/sender.c
@@ -22,6 +22,7 @@
 #include "rsync.h"
 
 extern int verbose;
+extern int dry_run;
 extern int do_xfers;
 extern int am_server;
 extern int am_daemon;
@@ -144,8 +145,9 @@ void successful_send(int ndx)
 		rsyserr(FERROR, errno, "sender failed to remove %s", fname);
 }
 
-void write_ndx_and_attrs(int f_out, int ndx, int iflags,
-			 uchar fnamecmp_type, char *buf, int len)
+static void write_ndx_and_attrs(int f_out, int ndx, int iflags,
+				const char *fname, struct file_struct *file,
+				uchar fnamecmp_type, char *buf, int len)
 {
 	write_ndx(f_out, ndx);
 	if (protocol_version < 29)
@@ -155,6 +157,10 @@ void write_ndx_and_attrs(int f_out, int 
 		write_byte(f_out, fnamecmp_type);
 	if (iflags & ITEM_XNAME_FOLLOWS)
 		write_vstring(f_out, buf, len);
+#ifdef SUPPORT_XATTRS
+	if (iflags & ITEM_REPORT_XATTR && !dry_run)
+		send_xattr_request(fname, file, f_out);
+#endif
 }
 
 void send_files(int f_in, int f_out)
@@ -183,8 +189,8 @@ void send_files(int f_in, int f_out)
 			send_extra_file_list(f_out, FILECNT_LOOKAHEAD);
 
 		/* This call also sets cur_flist. */
-		ndx = read_ndx_and_attrs(f_in, f_out, &iflags,
-					 &fnamecmp_type, xname, &xlen);
+		ndx = read_ndx_and_attrs(f_in, &iflags, &fnamecmp_type,
+					 xname, &xlen);
 		if (ndx == NDX_DONE) {
 			if (inc_recurse && first_flist) {
 				flist_free(first_flist);
@@ -201,6 +207,9 @@ void send_files(int f_in, int f_out)
 			continue;
 		}
 
+		if (inc_recurse)
+			send_extra_file_list(f_out, FILECNT_LOOKAHEAD);
+
 		file = cur_flist->files[ndx - cur_flist->ndx_start];
 		if (F_ROOTDIR(file)) {
 			path = F_ROOTDIR(file);
@@ -215,8 +224,13 @@ void send_files(int f_in, int f_out)
 		if (verbose > 2)
 			rprintf(FINFO, "send_files(%d, %s%s%s)\n", ndx, path,slash,fname);
 
+		if (iflags & ITEM_REPORT_XATTR)
+			recv_xattr_request(file, f_in);
+
 		if (!(iflags & ITEM_TRANSFER)) {
 			maybe_log_item(file, iflags, itemizing, xname);
+			write_ndx_and_attrs(f_out, ndx, iflags, fname, file,
+					    fnamecmp_type, xname, xlen);
 			continue;
 		}
 		if (phase == 2) {
@@ -251,8 +265,8 @@ void send_files(int f_in, int f_out)
 
 		if (!do_xfers) { /* log the transfer */
 			log_item(FCLIENT, file, &stats, iflags, NULL);
-			write_ndx_and_attrs(f_out, ndx, iflags, fnamecmp_type,
-					    xname, xlen);
+			write_ndx_and_attrs(f_out, ndx, iflags, fname, file,
+					    fnamecmp_type, xname, xlen);
 			continue;
 		}
 
@@ -305,8 +319,8 @@ void send_files(int f_in, int f_out)
 				path,slash,fname, (double)st.st_size);
 		}
 
-		write_ndx_and_attrs(f_out, ndx, iflags, fnamecmp_type,
-				    xname, xlen);
+		write_ndx_and_attrs(f_out, ndx, iflags, fname, file,
+				    fnamecmp_type, xname, xlen);
 		write_sum_head(f_xfer, s);
 
 		if (verbose > 2)
--- old/testsuite/xattrs.test
+++ new/testsuite/xattrs.test
@@ -0,0 +1,56 @@
+#! /bin/sh
+
+# This program is distributable under the terms of the GNU GPL (see
+# COPYING).
+
+# Test that rsync handles basic xattr preservation.
+
+. $srcdir/testsuite/rsync.fns
+
+$RSYNC --version | grep ", xattrs" >/dev/null || test_skipped "Rsync is configured without xattr support"
+
+case "$RSYNC" in
+*protocol=29*) test_skipped "xattr support requires protocol 30" ;;
+esac
+
+makepath "$fromdir/foo"
+echo something >"$fromdir/file1"
+echo else >"$fromdir/file2"
+echo last >"$fromdir/foo/file3"
+
+makepath "$todir/foo"
+echo wow >"$todir/file1"
+cp -p "$fromdir/foo/file3" "$todir/foo"
+
+files='foo file1 file2 foo/file3'
+
+cd "$fromdir"
+
+setfattr -n user.short -v 'this is short' file1 2>/dev/null || test_skipped "Unable to set an xattr"
+setfattr -n user.long -v 'this is a long attribute that will be truncated in the initial data send' file1
+setfattr -n user.good -v 'this is good' file1
+setfattr -n user.nice -v 'this is nice' file1
+
+setfattr -n user.foo -v foo file2
+setfattr -n user.bar -v bar file2
+
+setfattr -n user.foo -v 'new foo' foo/file3
+setfattr -n user.bar -v 'new bar' foo/file3
+setfattr -n user.long -v 'this is also a long attribute that will be truncated in the initial data send' foo/file3
+setfattr -n user.equal -v 'this long attribute should remain the same and not need to be transferred' foo/file3
+
+setfattr -n user.short -v 'old short' "$todir/file1"
+setfattr -n user.extra -v 'remove me' "$todir/file1"
+
+setfattr -n user.foo -v 'old foo' "$todir/foo/file3"
+setfattr -n user.equal -v 'this long attribute should remain the same and not need to be transferred' "$todir/foo/file3"
+
+$RSYNC -avX . "$todir/"
+
+getfattr -d $files >"$scratchdir/xattrs.txt"
+
+cd "$todir"
+getfattr -d $files | diff $diffopt "$scratchdir/xattrs.txt" -
+
+# The script would have aborted on error, so getting here means we've won.
+exit 0
--- old/xattrs.c
+++ new/xattrs.c
@@ -0,0 +1,688 @@
+/*
+ * Extended Attribute support for rsync.
+ * Written by Jay Fenlason, vaguely based on the ACLs patch.
+ *
+ * Copyright (C) 2004 Red Hat, Inc.
+ * Copyright (C) 2006, 2007 Wayne Davison
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "rsync.h"
+#include "lib/sysxattrs.h"
+
+#ifdef SUPPORT_XATTRS
+
+extern int dry_run;
+extern int am_root;
+extern int am_sender;
+extern int read_only;
+extern int list_only;
+extern int checksum_seed;
+
+#define RSYNC_XAL_INITIAL 5
+#define RSYNC_XAL_LIST_INITIAL 100
+
+#define MAX_FULL_DATUM 32
+
+#define HAS_PREFIX(str, prfx) (*(str) == *(prfx) \
+			    && strncmp(str, prfx, sizeof (prfx) - 1) == 0)
+
+#define USER_PREFIX "user."
+#define UPRE_LEN ((int)sizeof USER_PREFIX - 1)
+#define SYSTEM_PREFIX "system."
+#define SPRE_LEN ((int)sizeof SYSTEM_PREFIX - 1)
+
+#ifdef HAVE_LINUX_XATTRS
+#define RPRE_LEN 0
+#else
+#define RSYNC_PREFIX "rsync."
+#define RPRE_LEN ((int)sizeof RSYNC_PREFIX - 1)
+#endif
+
+typedef struct {
+	char *datum, *name;
+	size_t datum_len, name_len;
+} rsync_xa;
+
+static size_t namebuf_len = 0;
+static char *namebuf = NULL;
+
+static item_list empty_xattr = EMPTY_ITEM_LIST;
+static item_list rsync_xal_l = EMPTY_ITEM_LIST;
+
+/* ------------------------------------------------------------------------- */
+
+static void rsync_xal_free(item_list *xalp)
+{
+	size_t i;
+	rsync_xa *rxas = xalp->items;
+
+	for (i = 0; i < xalp->count; i++) {
+		free(rxas[i].datum);
+		/*free(rxas[i].name);*/
+	}
+	xalp->count = 0;
+}
+
+void free_xattr(statx *sxp)
+{
+	if (!sxp->xattr)
+		return;
+	rsync_xal_free(sxp->xattr);
+	free(sxp->xattr);
+	sxp->xattr = NULL;
+}
+
+static int rsync_xal_compare_names(const void *x1, const void *x2)
+{
+	const rsync_xa *xa1 = x1;
+	const rsync_xa *xa2 = x2;
+	return strcmp(xa1->name, xa2->name);
+}
+
+static ssize_t get_xattr_names(const char *fname)
+{
+	ssize_t list_len;
+
+	if (!namebuf) {
+		namebuf_len = 1024;
+		namebuf = new_array(char, namebuf_len);
+		if (!namebuf)
+			out_of_memory("get_xattr_names");
+	}
+
+	/* The length returned includes all the '\0' terminators. */
+	list_len = sys_llistxattr(fname, namebuf, namebuf_len);
+	if (list_len > (ssize_t)namebuf_len) {
+		list_len = -1;
+		errno = ERANGE;
+	}
+	if (list_len < 0) {
+		if (errno == ENOTSUP)
+			return 0;
+		if (errno == ERANGE) {
+			list_len = sys_llistxattr(fname, NULL, 0);
+			if (list_len < 0) {
+				rsyserr(FERROR, errno,
+					"get_xattr_names: llistxattr(\"%s\",0) failed",
+					fname);
+				return -1;
+			}
+			if (namebuf_len)
+				free(namebuf);
+			namebuf_len = list_len + 1024;
+			namebuf = new_array(char, namebuf_len);
+			if (!namebuf)
+				out_of_memory("get_xattr_names");
+			list_len = sys_llistxattr(fname, namebuf, namebuf_len);
+			if (list_len < 0) {
+				rsyserr(FERROR, errno,
+					"get_xattr_names: llistxattr(\"%s\",%ld) failed",
+					fname, (long)namebuf_len);
+				return -1;
+			}
+		} else {
+			rsyserr(FERROR, errno,
+				"get_xattr_names: llistxattr(\"%s\",%ld) failed",
+				fname, (long)namebuf_len);
+			return -1;
+		}
+	}
+
+	return list_len;
+}
+
+/* On entry, the *len_ptr parameter contains the size of the extra space we
+ * should allocate when we create a buffer for the data.  On exit, it contains
+ * the length of the datum. */
+static char *get_xattr_data(const char *fname, const char *name, size_t *len_ptr)
+{
+	size_t datum_len = sys_lgetxattr(fname, name, NULL, 0);
+	char *ptr;
+
+	if (datum_len == (size_t)-1) {
+		if (errno == ENOTSUP)
+			return NULL;
+		rsyserr(FERROR, errno,
+			"get_xattr_data: lgetxattr(\"%s\",\"%s\",0) failed",
+			fname, name);
+		return NULL;
+	}
+
+	if (datum_len + *len_ptr < datum_len /* checks for overflow */
+	 || !(ptr = new_array(char, datum_len + *len_ptr)))
+		out_of_memory("get_xattr_data");
+
+	*len_ptr = datum_len;
+
+	if (datum_len) {
+		size_t len = sys_lgetxattr(fname, name, ptr, datum_len);
+		if (len != datum_len) {
+			if (len == (size_t)-1) {
+				rsyserr(FERROR, errno,
+				    "get_xattr_data: lgetxattr(\"%s\",\"%s\",%ld)"
+				    " failed", fname, name, (long)datum_len);
+			} else {
+				rprintf(FERROR,
+				    "get_xattr_data: lgetxattr(\"%s\",\"%s\",%ld)"
+				    " returned %ld\n", fname, name,
+				    (long)datum_len, (long)len);
+			}
+			free(ptr);
+			return NULL;
+		}
+	}
+
+	return ptr;
+}
+
+static int rsync_xal_get(const char *fname, item_list *xalp)
+{
+	ssize_t list_len, name_len;
+	size_t datum_len, name_offset;
+	char *name, *ptr;
+	int user_only = am_sender ? 0 : !am_root;
+
+	/* This puts the name list into the "namebuf" buffer. */
+	if ((list_len = get_xattr_names(fname)) < 0)
+		return -1;
+
+	for (name = namebuf; list_len > 0; name += name_len) {
+		rsync_xa *rxas;
+
+		name_len = strlen(name) + 1;
+		list_len -= name_len;
+
+#ifdef HAVE_LINUX_XATTRS
+		/* We always ignore the system namespace, and non-root
+		 * ignores everything but the user namespace. */
+		if (user_only ? !HAS_PREFIX(name, USER_PREFIX)
+			      : HAS_PREFIX(name, SYSTEM_PREFIX))
+			continue;
+#endif
+
+		datum_len = name_len; /* Pass extra size to get_xattr_data() */
+		if (!(ptr = get_xattr_data(fname, name, &datum_len)))
+			return -1;
+
+		if (datum_len > MAX_FULL_DATUM) {
+			/* For large datums, we store a flag and a checksum. */
+			name_offset = 1 + MAX_DIGEST_LEN;
+			sum_init(checksum_seed);
+			sum_update(ptr, datum_len);
+			free(ptr);
+
+			if (!(ptr = new_array(char, name_offset + name_len)))
+				out_of_memory("rsync_xal_get");
+			*ptr = 0;
+			sum_end(ptr + 1);
+		} else
+			name_offset = datum_len;
+
+		rxas = EXPAND_ITEM_LIST(xalp, rsync_xa, RSYNC_XAL_INITIAL);
+		rxas->name = ptr + name_offset;
+		memcpy(rxas->name, name, name_len);
+		rxas->datum = ptr;
+		rxas->name_len = name_len;
+		rxas->datum_len = datum_len;
+	}
+	if (xalp->count > 1)
+		qsort(xalp->items, xalp->count, sizeof (rsync_xa), rsync_xal_compare_names);
+	return 0;
+}
+
+/* Read the xattr(s) for this filename. */
+int get_xattr(const char *fname, statx *sxp)
+{
+	sxp->xattr = new(item_list);
+	*sxp->xattr = empty_xattr;
+	if (rsync_xal_get(fname, sxp->xattr) < 0) {
+		free_xattr(sxp);
+		return -1;
+	}
+	return 0;
+}
+
+static int find_matching_xattr(item_list *xalp)
+{
+	size_t i, j;
+	item_list *lst = rsync_xal_l.items;
+
+	for (i = 0; i < rsync_xal_l.count; i++) {
+		rsync_xa *rxas1 = lst[i].items;
+		rsync_xa *rxas2 = xalp->items;
+
+		/* Wrong number of elements? */
+		if (lst[i].count != xalp->count)
+			continue;
+		/* any elements different? */
+		for (j = 0; j < xalp->count; j++) {
+			if (rxas1[j].name_len != rxas2[j].name_len
+			 || rxas1[j].datum_len != rxas2[j].datum_len
+			 || strcmp(rxas1[j].name, rxas2[j].name))
+				break;
+			if (rxas1[j].datum_len > MAX_FULL_DATUM) {
+				if (memcmp(rxas1[j].datum + 1,
+					   rxas2[j].datum + 1,
+					   MAX_DIGEST_LEN) != 0)
+					break;
+			} else {
+				if (memcmp(rxas1[j].datum, rxas2[j].datum,
+					   rxas2[j].datum_len))
+					break;
+			}
+		}
+		/* no differences found.  This is The One! */
+		if (j == xalp->count)
+			return i;
+	}
+
+	return -1;
+}
+
+/* Store *xalp on the end of rsync_xal_l */
+static void rsync_xal_store(item_list *xalp)
+{
+	item_list *new_lst = EXPAND_ITEM_LIST(&rsync_xal_l, item_list, RSYNC_XAL_LIST_INITIAL);
+	/* Since the following call starts a new list, we know it will hold the
+	 * entire initial-count, not just enough space for one new item. */
+	*new_lst = empty_xattr;
+	(void)EXPAND_ITEM_LIST(new_lst, rsync_xa, xalp->count);
+	memcpy(new_lst->items, xalp->items, xalp->count * sizeof (rsync_xa));
+	new_lst->count = xalp->count;
+	xalp->count = 0;
+}
+
+/* Send the make_xattr()-generated xattr list for this flist entry. */
+int send_xattr(statx *sxp, int f)
+{
+	int ndx = find_matching_xattr(sxp->xattr);
+
+	/* Send 0 (-1 + 1) to indicate that literal xattr data follows. */
+	write_abbrevint(f, ndx + 1);
+
+	if (ndx < 0) {
+		rsync_xa *rxa;
+		int count = sxp->xattr->count;
+		write_abbrevint(f, count);
+		for (rxa = sxp->xattr->items; count--; rxa++) {
+#ifdef HAVE_LINUX_XATTRS
+			write_abbrevint(f, rxa->name_len);
+			write_abbrevint(f, rxa->datum_len);
+			write_buf(f, rxa->name, rxa->name_len);
+#else
+			/* We strip the rsync prefix from disguised namespaces
+			 * and put everything else in the user namespace. */
+			if (HAS_PREFIX(rxa->name, RSYNC_PREFIX)
+			 && rxa->name[RPRE_LEN] != '%') {
+				write_abbrevint(f, rxa->name_len - RPRE_LEN);
+				write_abbrevint(f, rxa->datum_len);
+				write_buf(f, rxa->name + RPRE_LEN, rxa->name_len - RPRE_LEN);
+			} else {
+				write_abbrevint(f, rxa->name_len + UPRE_LEN);
+				write_abbrevint(f, rxa->datum_len);
+				write_buf(f, USER_PREFIX, UPRE_LEN);
+				write_buf(f, rxa->name, rxa->name_len);
+			}
+#endif
+			if (rxa->datum_len > MAX_FULL_DATUM)
+				write_buf(f, rxa->datum + 1, MAX_DIGEST_LEN);
+			else
+				write_buf(f, rxa->datum, rxa->datum_len);
+		}
+		ndx = rsync_xal_l.count; /* pre-incremented count */
+		rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
+	}
+
+	return ndx;
+}
+
+/* Return a flag indicating if we need to change a file's xattrs.  If
+ * "find_all" is specified, also mark any abbreviated xattrs that we
+ * need so that send_xattr_request() can tell the sender about them. */
+int xattr_diff(struct file_struct *file, statx *sxp, int find_all)
+{
+	item_list *lst = rsync_xal_l.items;
+	rsync_xa *snd_rxa, *rec_rxa;
+	int snd_cnt, rec_cnt;
+	int cmp, same, xattrs_equal = 1;
+
+	if (!XATTR_READY(*sxp)) {
+		rec_rxa = NULL;
+		rec_cnt = 0;
+	} else {
+		rec_rxa = sxp->xattr->items;
+		rec_cnt = sxp->xattr->count;
+	}
+
+	if (F_XATTR(file) >= 0)
+		lst += F_XATTR(file);
+	else
+		lst = &empty_xattr;
+
+	snd_rxa = lst->items;
+	snd_cnt = lst->count;
+
+	/* If the count of the sender's xattrs is different from our
+	 * (receiver's) xattrs, the lists are not the same. */
+	if (snd_cnt != rec_cnt) {
+		if (!find_all)
+			return 1;
+		xattrs_equal = 0;
+	}
+
+	while (snd_cnt) {
+		cmp = rec_cnt ? strcmp(snd_rxa->name, rec_rxa->name) : -1;
+		if (cmp > 0)
+			same = 0;
+		else if (snd_rxa->datum_len > MAX_FULL_DATUM) {
+			same = cmp == 0 && snd_rxa->datum_len == rec_rxa->datum_len
+			    && memcmp(snd_rxa->datum + 1, rec_rxa->datum + 1,
+				      MAX_DIGEST_LEN) == 0;
+			/* Flag unrequested items that we need. */
+			if (/*!same &&*/ find_all && snd_rxa->datum[0] == 0)
+				snd_rxa->datum[0] = 1;
+		} else {
+			same = cmp == 0 && snd_rxa->datum_len == rec_rxa->datum_len
+			    && memcmp(snd_rxa->datum, rec_rxa->datum,
+				      snd_rxa->datum_len) == 0;
+		}
+		if (!same) {
+			if (!find_all)
+				return 1;
+			xattrs_equal = 0;
+		}
+
+		if (cmp <= 0) {
+			snd_rxa++;
+			snd_cnt--;
+		}
+		if (cmp >= 0) {
+			rec_rxa++;
+			rec_cnt--;
+		}
+	}
+
+	if (rec_cnt)
+		xattrs_equal = 0;
+
+	return !xattrs_equal;
+}
+
+/* When called by the generator with a NULL fname, this tells the sender
+ * which abbreviated xattr values we need.  When called by the sender
+ * (with a non-NULL fname), we send all the extra xattr data it needs. */
+void send_xattr_request(const char *fname, struct file_struct *file, int f_out)
+{
+	item_list *lst = rsync_xal_l.items;
+	int j, cnt, prior_req = -1;
+	rsync_xa *rxa;
+
+	lst += F_XATTR(file);
+	cnt = lst->count;
+	for (rxa = lst->items, j = 0; j < cnt; rxa++, j++) {
+		if (rxa->datum_len <= MAX_FULL_DATUM
+		 || rxa->datum[0] != 1)
+			continue;
+
+		/* Flag that we handled this abbreviated item. */
+		rxa->datum[0] = 2;
+
+		write_abbrevint(f_out, j - prior_req);
+		prior_req = j;
+
+		if (fname) {
+			size_t len = 0;
+			char *ptr;
+
+			/* Re-read the long datum. */
+			if (!(ptr = get_xattr_data(fname, rxa->name, &len)))
+				continue;
+
+			write_abbrevint(f_out, len); /* length might have changed! */
+			write_buf(f_out, ptr, len);
+			free(ptr);
+		}
+	}
+
+	write_byte(f_out, 0); /* end the list */
+}
+
+/* When called by the sender, read the request from the generator and mark
+ * any needed xattrs with a flag that lets us know they need to be sent to
+ * the receiver.  When called by the receiver, reads the sent data and
+ * stores it in place of its checksum. */
+void recv_xattr_request(struct file_struct *file, int f_in)
+{
+	item_list *lst = rsync_xal_l.items;
+	char *old_datum, *name;
+	rsync_xa *rxa;
+	int rel_pos, cnt;
+
+	if (F_XATTR(file) >= 0)
+		lst += F_XATTR(file);
+	else
+		exit_cleanup(RERR_STREAMIO); /* XXX */
+
+	cnt = lst->count;
+	rxa = lst->items;
+	rxa -= 1;
+	while ((rel_pos = read_abbrevint(f_in)) != 0) {
+		rxa += rel_pos;
+		cnt -= rel_pos;
+		if (cnt < 0 || rxa->datum_len <= MAX_FULL_DATUM
+		 || rxa->datum[0] != 0)
+			exit_cleanup(RERR_STREAMIO); /* XXX */
+
+		if (am_sender) {
+			rxa->datum[0] = 1;
+			continue;
+		}
+
+		old_datum = rxa->datum;
+		rxa->datum_len = read_abbrevint(f_in);
+
+		if (rxa->name_len + rxa->datum_len < rxa->name_len)
+			out_of_memory("recv_xattr_request"); /* overflow */
+		rxa->datum = new_array(char, rxa->datum_len + rxa->name_len);
+		if (!rxa->datum)
+			out_of_memory("recv_xattr_request");
+		name = rxa->datum + rxa->datum_len;
+		memcpy(name, rxa->name, rxa->name_len);
+		rxa->name = name;
+		free(old_datum);
+		read_buf(f_in, rxa->datum, rxa->datum_len);
+	}
+}
+
+/* ------------------------------------------------------------------------- */
+
+/* receive and build the rsync_xattr_lists */
+void receive_xattr(struct file_struct *file, int f)
+{
+	static item_list temp_xattr = EMPTY_ITEM_LIST;
+	int count;
+	int ndx = read_abbrevint(f);
+
+	if (ndx < 0 || (size_t)ndx > rsync_xal_l.count) {
+		rprintf(FERROR, "receive_xattr: xa index %d out of"
+			" range for %s\n", ndx, f_name(file, NULL));
+		exit_cleanup(RERR_STREAMIO);
+	}
+
+	if (ndx != 0) {
+		F_XATTR(file) = ndx - 1;
+		return;
+	}
+	
+	if ((count = read_abbrevint(f)) != 0) {
+		(void)EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, count);
+		temp_xattr.count = 0;
+	}
+
+	while (count--) {
+		char *ptr, *name;
+		rsync_xa *rxa;
+		size_t name_len = read_abbrevint(f);
+		size_t datum_len = read_abbrevint(f);
+		size_t dget_len = datum_len > MAX_FULL_DATUM ? 1 + MAX_DIGEST_LEN : datum_len;
+#ifdef HAVE_LINUX_XATTRS
+		size_t extra_len = 0;
+#else
+		size_t extra_len = am_root ? RPRE_LEN : 0;
+		if (dget_len + extra_len < dget_len)
+			out_of_memory("receive_xattr"); /* overflow */
+#endif
+		if (dget_len + extra_len + name_len < dget_len)
+			out_of_memory("receive_xattr"); /* overflow */
+		ptr = new_array(char, dget_len + extra_len + name_len);
+		if (!ptr)
+			out_of_memory("receive_xattr");
+		name = ptr + dget_len + extra_len;
+		read_buf(f, name, name_len);
+		if (dget_len == datum_len)
+			read_buf(f, ptr, dget_len);
+		else {
+			*ptr = 0;
+			read_buf(f, ptr + 1, MAX_DIGEST_LEN);
+		}
+#ifdef HAVE_LINUX_XATTRS
+		/* Non-root can only save the user namespace. */
+		if (!am_root && !HAS_PREFIX(name, USER_PREFIX)) {
+			free(ptr);
+			continue;
+		}
+#else
+		/* This OS only has a user namespace, so we either
+		 * strip the user prefix, or we put a non-user
+		 * namespace inside our rsync hierarchy. */
+		if (HAS_PREFIX(name, USER_PREFIX)) {
+			name += UPRE_LEN;
+			name_len -= UPRE_LEN;
+		} else if (am_root) {
+			name -= RPRE_LEN;
+			name_len += RPRE_LEN;
+			memcpy(name, RSYNC_PREFIX, RPRE_LEN);
+		} else {
+			free(ptr);
+			continue;
+		}
+#endif
+		rxa = EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, 1);
+		rxa->name = name;
+		rxa->datum = ptr;
+		rxa->name_len = name_len;
+		rxa->datum_len = datum_len;
+	}
+
+	ndx = rsync_xal_l.count; /* pre-incremented count */
+	rsync_xal_store(&temp_xattr); /* adds item to rsync_xal_l */
+
+	F_XATTR(file) = ndx;
+}
+
+/* Turn the xattr data in statx into cached xattr data, setting the index
+ * values in the file struct. */
+void cache_xattr(struct file_struct *file, statx *sxp)
+{
+	int ndx;
+
+	if (!sxp->xattr)
+		return;
+
+	ndx = find_matching_xattr(sxp->xattr);
+	if (ndx < 0)
+		rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
+
+	F_XATTR(file) = ndx;
+}
+
+static int rsync_xal_set(const char *fname, item_list *xalp)
+{
+	rsync_xa *rxas = xalp->items;
+	ssize_t list_len;
+	size_t i;
+	char *name;
+	int name_len, status, ret = 0;
+
+	/* This puts the current name list into the "namebuf" buffer. */
+	if ((list_len = get_xattr_names(fname)) < 0)
+		return -1;
+
+	for (i = 0; i < xalp->count; i++) {
+		if ((size_t)(rxas[i].name - rxas[i].datum) < rxas[i].datum_len) {
+			rprintf(FERROR, "Abbreviated xattr value, %s, not received for %s\n",
+				rxas[i].name, full_fname(fname));
+			exit_cleanup(RERR_STREAMIO);
+		}
+		status = sys_lsetxattr(fname, rxas[i].name, rxas[i].datum, rxas[i].datum_len);
+		if (status < 0) {
+			rsyserr(FERROR, errno,
+				"rsync_xal_set: lsetxattr(\"%s\",\"%s\") failed",
+				fname, rxas[i].name);
+			ret = -1;
+		}
+	}
+
+	/* Remove any extraneous names. */
+	for (name = namebuf; list_len > 0; name += name_len) {
+		name_len = strlen(name) + 1;
+		list_len -= name_len;
+
+#ifdef HAVE_LINUX_XATTRS
+		/* We always ignore the system namespace, and non-root
+		 * ignores everything but the user namespace. */
+		if (am_root ? HAS_PREFIX(name, SYSTEM_PREFIX)
+			    : !HAS_PREFIX(name, USER_PREFIX))
+			continue;
+#endif
+
+		for (i = 0; i < xalp->count; i++) {
+			if (strcmp(name, rxas[i].name) == 0)
+				break;
+		}
+		if (i == xalp->count) {
+			int status = sys_lremovexattr(fname, name);
+			if (status < 0) {
+				rsyserr(FERROR, errno,
+					"rsync_xal_clear: lremovexattr(\"%s\",\"%s\") failed",
+					fname, name);
+				ret = -1;
+			}
+		}
+	}
+
+	return ret;
+}
+
+/* Set extended attributes on indicated filename. */
+int set_xattr(const char *fname, const struct file_struct *file, UNUSED(statx *sxp))
+{
+	int ndx;
+	item_list *lst = rsync_xal_l.items;
+
+	if (dry_run)
+		return 1; /* FIXME: --dry-run needs to compute this value */
+
+	if (read_only || list_only) {
+		errno = EROFS;
+		return -1;
+	}
+
+	ndx = F_XATTR(file);
+	return rsync_xal_set(fname, lst + ndx);
+}
+
+#endif /* SUPPORT_XATTRS */