Got rid of a superfluous extern.

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

Depends-On-Patch: acls.diff

This patch adds preliminary support for extended attributes.

After applying this patch, run these commands for a successful build:

    ./prepare-source
    ./configure --enable-acl-support --enable-xattr-support
    make

TODO:

 - This patch needs to more efficiently handle large xattrs, especially when
   they're unchanged.

 - Extraneous xattr values need to be removed from files that are not being
   recreated.

 - We need to affect the itemized output to know when xattrs are being updated.

 - We need to affect the --link-dest option to avoid hard-linking two files
   that differ in their xattrs (when --xattrs was specified).

--- 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/permstring.o lib/pool_alloc.o lib/sysacls.o @LIBOBJS@
+	lib/permstring.o lib/pool_alloc.o lib/sysacls.o lib/sysxattr.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=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 flist.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 xattr.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/acls.c
+++ new/acls.c
@@ -31,6 +31,7 @@ extern int read_only;
 extern int list_only;
 extern int orig_umask;
 extern int preserve_acls;
+extern int preserve_xattrs;
 extern unsigned int file_struct_len;
 
 /* === ACL structures === */
@@ -742,6 +743,10 @@ void receive_acl(struct file_struct *fil
 	type = SMB_ACL_TYPE_ACCESS;
 	racl_list = &access_acl_list;
 	ndx_ptr = (char*)file + file_struct_len;
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs)
+		ndx_ptr += 4;
+#endif
 	do {
 		char tag = read_byte(f);
 		int ndx;
@@ -801,6 +806,10 @@ void cache_acl(struct file_struct *file,
 	racl = sxp->acc_acl;
 	racl_list = &access_acl_list;
 	ndx_ptr = (char*)file + file_struct_len;
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs)
+		ndx_ptr += 4;
+#endif
 	do {
 		if (!racl)
 			ndx = -1;
@@ -921,6 +930,10 @@ int set_acl(const char *fname, const str
 
 	type = SMB_ACL_TYPE_ACCESS;
 	ndx_ptr = (char*)file + file_struct_len;
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs)
+		ndx_ptr += 4;
+#endif
 	do {
 		acl_duo *duo_item;
 		BOOL eq;
--- old/backup.c
+++ new/backup.c
@@ -30,6 +30,7 @@ extern char *backup_dir;
 
 extern int am_root;
 extern int preserve_acls;
+extern int preserve_xattrs;
 extern int preserve_devices;
 extern int preserve_specials;
 extern int preserve_links;
@@ -136,6 +137,9 @@ 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
@@ -144,6 +148,12 @@ static int make_bak_dir(char *fullpath)
 					cache_acl(file, &sx);
 				}
 #endif
+#ifdef SUPPORT_XATTRS
+				if (preserve_xattrs) {
+					get_xattr(rel, &sx);
+					cache_xattr(file, &sx);
+				}
+#endif
 				set_file_attrs(fullpath, file, NULL, 0);
 				free(file);
 			}
@@ -195,6 +205,9 @@ static int keep_backup(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 */
@@ -208,6 +221,12 @@ static int keep_backup(char *fname)
 		cache_acl(file, &sx);
 	}
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs) {
+		get_xattr(fname, &sx);
+		cache_xattr(file, &sx);
+	}
+#endif
 
 	/* Check to see if this is a device file, or link */
 	if ((am_root && preserve_devices && IS_DEVICE(file->mode))
--- old/configure.in
+++ new/configure.in
@@ -856,6 +856,35 @@ samba_cv_HAVE_ACL_GET_PERM_NP=yes,samba_
   AC_MSG_RESULT(no)
 )
 
+AC_CHECK_HEADERS(attr/xattr.h)
+AC_CHECK_HEADERS(sys/xattr.h)
+AC_MSG_CHECKING(whether to support extended attributes)
+AC_ARG_ENABLE(xattr-support,
+AC_HELP_STRING([--enable-xattr-support], [Include extended attribute support (default=no)]),
+[ case "$enableval" in
+  yes)
+      case "$host_os" in
+      *linux*)
+            AC_MSG_RESULT(Using Linux xattrs)
+            AC_DEFINE(HAVE_LINUX_XATTRS, 1, [True if you have Linux xattrs])
+            ;;
+      darwin*)
+            AC_MSG_RESULT(Using OS X xattrs)
+            AC_DEFINE(HAVE_OSX_XATTRS, 1, [True if you have Mac OS X xattrs])
+            ;;
+      *)
+            AC_MSG_RESULT(Xattrs requested but not Linux or OS X.  Good luck...)
+            ;;
+      esac
+      ;;
+  *)
+      AC_MSG_RESULT(no)
+      AC_DEFINE(HAVE_NO_XATTRS, 1, [True if you don't have extended attributes])
+  esac ],
+  AC_MSG_RESULT(no)
+  AC_DEFINE(HAVE_NO_XATTRS, 1, [True if you don't have extended attributes])
+)
+
 AC_CONFIG_FILES([Makefile lib/dummy zlib/dummy popt/dummy shconfig])
 AC_OUTPUT
 
--- old/flist.c
+++ new/flist.c
@@ -41,6 +41,7 @@ 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;
@@ -498,7 +499,7 @@ static struct file_struct *receive_file_
 	char thisname[MAXPATHLEN];
 	unsigned int l1 = 0, l2 = 0;
 	int alloc_len, basename_len, dirname_len, linkname_len, sum_len;
-#ifdef SUPPORT_ACLS
+#if defined SUPPORT_ACLS || defined SUPPORT_XATTRS
 	int xtra_len;
 #endif
 	OFF_T file_length;
@@ -610,10 +611,16 @@ static struct file_struct *receive_file_
 		xtra_len = (S_ISDIR(mode) ? 2 : 1) * 4;
 	else
 		xtra_len = 0;
+#elif defined SUPPORT_XATTRS
+	xtra_len = 0;
+#endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs)
+		xtra_len += 4;
 #endif
 
 	alloc_len = file_struct_len + dirname_len + basename_len
-#ifdef SUPPORT_ACLS
+#if defined SUPPORT_ACLS || defined SUPPORT_XATTRS
 		  + xtra_len
 #endif
 		  + linkname_len + sum_len;
@@ -622,7 +629,7 @@ static struct file_struct *receive_file_
 	file = (struct file_struct *)bp;
 	memset(bp, 0, file_struct_len);
 	bp += file_struct_len;
-#ifdef SUPPORT_ACLS
+#if defined SUPPORT_ACLS || defined SUPPORT_XATTRS
 	bp += xtra_len;
 #endif
 
@@ -723,6 +730,10 @@ static struct file_struct *receive_file_
 	if (preserve_acls)
 		receive_acl(file, f);
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs)
+		receive_xattr(file, f );
+#endif
 
 	return file;
 }
@@ -974,7 +985,7 @@ static struct file_struct *send_file_nam
 					  unsigned short flags)
 {
 	struct file_struct *file;
-#ifdef SUPPORT_ACLS
+#if defined SUPPORT_ACLS || defined SUPPORT_XATTRS
 	statx sx;
 #endif
 
@@ -994,6 +1005,13 @@ static struct file_struct *send_file_nam
 			return NULL;
 	}
 #endif
+#ifdef SUPPORT_XATTRS
+	if (preserve_xattrs) {
+		sx.xattr = NULL;
+		if (get_xattr(fname, &sx) < 0)
+			return NULL;
+	}
+#endif
 
 	maybe_emit_filelist_progress(flist->count + flist_count_offset);
 
@@ -1006,11 +1024,19 @@ static struct file_struct *send_file_nam
 		if (preserve_acls)
 			send_acl(&sx, f);
 #endif
+#ifdef SUPPORT_XATTRS
+		if (preserve_xattrs)
+			send_xattr(&sx, f);
+#endif
 	} else {
 #ifdef SUPPORT_ACLS
 		if (preserve_acls)
 			free_acl(&sx);
 #endif
+#ifdef SUPPORT_XATTRS
+		if (preserve_xattrs)
+			free_xattr(&sx);
+#endif
 	}
 	return file;
 }
--- old/lib/sysxattr.c
+++ new/lib/sysxattr.c
@@ -0,0 +1,87 @@
+/*
+ * 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 "sysxattr.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, int flags)
+{
+	return lsetxattr(path, name, value, size, flags);
+}
+
+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, int flags)
+{
+	return setxattr(path, name, value, size, 0, XATTR_NOFOLLOW | flags);
+}
+
+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);
+}
+
+#else
+
+#error You need to create xattr compatibility functions.
+
+#endif
+
+#endif /* SUPPORT_XATTRS */
--- old/lib/sysxattr.h
+++ new/lib/sysxattr.h
@@ -0,0 +1,24 @@
+#ifdef SUPPORT_XATTRS
+
+#if defined HAVE_ATTR_XATTR_H
+#include <attr/xattr.h>
+#elif defined HAVE_SYS_XATTR_H
+#include <sys/xattr.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 flags);
+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/options.c
+++ new/options.c
@@ -48,6 +48,7 @@ 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
@@ -236,8 +240,8 @@ static void print_rsync_version(enum log
 	rprintf(f, "Capabilities: %d-bit files, %ssocketpairs, %shard links, %ssymlinks,\n",
 		(int) (sizeof (OFF_T) * 8), got_socketpair, hardlinks, links);
 
-	rprintf(f, "              batchfiles, %sinplace, %sIPv6, %sACLs,\n",
-		have_inplace, ipv6, acls);
+	rprintf(f, "              batchfiles, %sinplace, %sIPv6, %sACLs, %sxattrs,\n",
+		have_inplace, ipv6, acls, xattrs);
 
 	/* Note that this field may not have type ino_t.  It depends
 	 * on the complicated interaction between largefile feature
@@ -289,7 +293,7 @@ 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");
@@ -314,6 +318,9 @@ 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");
@@ -436,6 +443,9 @@ 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 },
@@ -1117,6 +1127,17 @@ 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()
@@ -1563,6 +1584,10 @@ 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 (preserve_uid)
 		argstr[x++] = 'o';
 	if (preserve_gid)
--- old/rsync.c
+++ new/rsync.c
@@ -33,6 +33,7 @@
 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;
@@ -219,6 +220,10 @@ 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 && set_xattr(fname, file, sxp) == 0)
+		updated = 1;
+#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.
--- old/rsync.h
+++ new/rsync.h
@@ -500,6 +500,10 @@ struct idev {
 #define ACLS_NEED_MASK 1
 #endif
 
+#ifndef HAVE_NO_XATTRS
+#define SUPPORT_XATTRS 1
+#endif
+
 #define GID_NONE ((gid_t)-1)
 
 #define HL_CHECK_MASTER	0
@@ -694,6 +698,9 @@ 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)
--- 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) [non-standard]
+ -X, --xattrs                preserve extended attrs (implies -p) [n.s.]
  -o, --owner                 preserve owner (super-user only)
  -g, --group                 preserve group
      --devices               preserve device files (super-user only)
@@ -818,6 +819,11 @@ version makes it incompatible with sendi
 rsync unless you double the bf(--acls) option (e.g. bf(-AA)).  This
 doubling is not needed when pulling files from an older rsync.
 
+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/xattr.c
+++ new/xattr.c
@@ -0,0 +1,375 @@
+/*
+ * Extended Attribute support for rsync.
+ * Written by Jay Fenlason, vaguely based on the ACLs patch.
+ *
+ * Copyright (C) 2004 Red Hat, Inc.
+ * Copyright (C) 2006 Wayne Davison
+ *
+ * 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 "lib/sysxattr.h"
+
+#ifdef SUPPORT_XATTRS
+
+extern int dry_run;
+extern int read_only;
+extern int list_only;
+extern unsigned int file_struct_len;
+
+#define RSYNC_XAL_INITIAL 5
+#define RSYNC_XAL_LIST_INITIAL 100
+
+typedef struct {
+	char *name;
+	char *datum;
+	size_t name_len;
+	size_t datum_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;
+
+#ifdef HAVE_OSX_XATTRS
+#define UNIQUE_PREFIX "user.0S%." /* OSX */
+#define UPRE_LEN (sizeof UNIQUE_PREFIX - 1)
+#endif
+
+/* ------------------------------------------------------------------------- */
+
+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].name);
+		/* free(rxas[i].value); */
+	}
+	xalp->count = 0;
+}
+
+void free_xattr(statx *sxp)
+{
+	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 int rsync_xal_get(const char *fname, item_list *xalp)
+{
+	ssize_t name_size;
+	ssize_t datum_size;
+	ssize_t left;
+	char *name;
+	size_t len;
+	char *ptr;
+
+	if (!namebuf) {
+		namebuf_len = 1024;
+		namebuf = new_array(char, namebuf_len);
+		if (!namebuf)
+			out_of_memory("rsync_xal_get");
+	}
+
+	/* The length returned includes all the '\0' terminators. */
+	name_size = sys_llistxattr(fname, namebuf, namebuf_len);
+	if (name_size > (ssize_t)namebuf_len) {
+		name_size = -1;
+		errno = ERANGE;
+	}
+	if (name_size < 0) {
+		if (errno == ENOTSUP)
+			return 0;
+		if (errno == ERANGE) {
+			name_size = sys_llistxattr(fname, NULL, 0);
+			if (name_size < 0) {
+				rsyserr(FERROR, errno, "%s: rsync_xal_get: llistxattr",
+					fname);
+				return -1;
+			}
+			namebuf = realloc_array(namebuf, char, name_size + 1024);
+			if (!namebuf)
+				out_of_memory("rsync_xal_get");
+			namebuf_len = name_size + 1024;
+			name_size = sys_llistxattr(fname, namebuf, namebuf_len);
+			if (name_size < 0) {
+				rsyserr(FERROR, errno,
+				    "%s: rsync_xal_get: re-llistxattr failed",
+				    fname);
+				return -1;
+			}
+		} else {
+			rsyserr(FERROR, errno,
+			    "%s: rsync_xal_get: llistxattr failed:",
+			    fname);
+			return -1;
+		}
+	}
+	if (name_size == 0)
+		return 0;
+	for (left = name_size, name = namebuf; left > 0 ; left -= len, name += len) {
+		rsync_xa *rxas = EXPAND_ITEM_LIST(xalp, rsync_xa, RSYNC_XAL_INITIAL);
+
+		len = strlen(name) + 1;
+		datum_size = sys_lgetxattr(fname, name, NULL, 0);
+		if (datum_size < 0) {
+			if (errno == ENOTSUP)
+				return -1;
+			rsyserr(FERROR, errno,
+			    "%s: rsync_xal_get: lgetxattr %s failed",
+			    fname, name);
+			return -1;
+		}
+		ptr = new_array(char, len + datum_size);
+		if (!ptr)
+			out_of_memory("rsync_xal_get");
+		memcpy(ptr, name, len);
+		rxas->name_len = len;
+		rxas->name = ptr;
+		rxas->datum_len = datum_size;
+		rxas->datum = ptr + len;
+		if (datum_size) {
+			ssize_t size = sys_lgetxattr(fname, name, rxas->datum, datum_size);
+			if (size != datum_size) {
+				if (size < 0) {
+					rsyserr(FERROR, errno,
+					    "rsync_xal_get: lgetxattr(%s,%s)"
+					    " failed", fname, name);
+				} else {
+					rprintf(FERROR,
+					    "rsync_xal_get: lgetxattr(%s,%s)"
+					    " returned %ld instead of %ld\n",
+					    fname, name,
+					    (long)size, (long)datum_size);
+				}
+				return -1;
+			}
+		}
+	}
+	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)
+			 || 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. */
+void send_xattr(statx *sxp, int f)
+{
+	int ndx = find_matching_xattr(sxp->xattr);
+	if (ndx != -1) {
+		write_byte(f, 'x');
+		write_int(f, ndx);
+		rsync_xal_free(sxp->xattr);
+	} else {
+		rsync_xa *rxa;
+		int count = sxp->xattr->count;
+		write_byte(f, 'X');
+		write_int(f, count);
+		for (rxa = sxp->xattr->items; count--; rxa++) {
+#ifdef HAVE_OSX_XATTRS
+			if (strncmp(rxa->name, "user.", 5) != 0
+			 && strncmp(rxa->name, "system.", 7) != 0) {
+				write_int(f, rxa->name_len + UPRE_LEN);
+				write_int(f, rxa->datum_len);
+				write_buf(f, UNIQUE_PREFIX, UPRE_LEN);
+			} else
+#endif
+			{
+				write_int(f, rxa->name_len);
+				write_int(f, rxa->datum_len);
+			}
+			write_buf(f, rxa->name, rxa->name_len);
+			write_buf(f, rxa->datum, rxa->datum_len);
+		}
+		rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
+	}
+	free_xattr(sxp);
+}
+
+/* ------------------------------------------------------------------------- */
+
+/* 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 tag = read_byte(f);
+	char *ndx_ptr = (char*)file + file_struct_len;
+	int ndx;
+
+	if (tag == 'X') {
+		int i, count = read_int(f);
+		for (i = 0; i < count; i++) {
+			char *ptr;
+			rsync_xa *rxa;
+			size_t name_len = read_int(f);
+			size_t datum_len = read_int(f);
+			if (name_len + datum_len < name_len)
+				out_of_memory("receive_xattr"); /* overflow */
+			rxa = EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, count);
+			ptr = new_array(char, name_len + datum_len);
+			if (!ptr)
+				out_of_memory("receive_xattr");
+			read_buf(f, ptr, name_len);
+			read_buf(f, ptr + name_len, datum_len);
+			rxa->name_len = name_len;
+			rxa->datum_len = datum_len;
+			rxa->name = ptr;
+			rxa->datum = ptr + name_len;
+#ifdef HAVE_OSX_XATTRS
+			if (strncmp(rxa->name, UNIQUE_PREFIX, UPRE_LEN) == 0) {
+				rxa->name_len -= UPRE_LEN;
+				memmove(rxa->name, rxa->name + UPRE_LEN, rxa->name_len);
+			}
+#endif
+		}
+		ndx = rsync_xal_l.count; /* pre-incremented count */
+		rsync_xal_store(&temp_xattr); /* adds item to rsync_xal_l */
+	} else if (tag == 'x') {
+		ndx = read_int(f);
+		if (ndx < 0 || (size_t)ndx >= rsync_xal_l.count) {
+			rprintf(FERROR, "%s: receive_xattr: xa index %d out of range\n",
+				f_name(file, NULL), ndx);
+			exit_cleanup(RERR_STREAMIO);
+		}
+	} else {
+		rprintf(FERROR,
+		    "%s: receive_xattr: unknown extended attribute type tag: %c\n",
+		    f_name(file, NULL), tag);
+		exit_cleanup(RERR_STREAMIO);
+		ndx = 0; /* silence a compiler warning... */
+	}
+
+	SIVAL(ndx_ptr, 0, 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)
+{
+	char *ndx_ptr = (char*)file + file_struct_len;
+	int ndx;
+
+	if (!sxp->xattr)
+		return;
+
+	ndx = find_matching_xattr(sxp->xattr);
+	if (ndx == -1)
+		rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
+	free_xattr(sxp);
+
+	SIVAL(ndx_ptr, 0, ndx);
+}
+
+static int rsync_xal_set(const char *fname, item_list *xalp)
+{
+	rsync_xa *rxas = xalp->items;
+	size_t i;
+	int ret = 0;
+
+	for (i = 0; i < xalp->count; i++) {
+		int status = sys_lsetxattr(fname, rxas[i].name, rxas[i].datum, rxas[i].datum_len, 0);
+		if (status < 0) {
+			rsyserr(FERROR, errno, "%s: rsync_xal_set: lsetxattr %s failed",
+				fname, rxas[i].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;
+	char *ndx_ptr = (char*)file + file_struct_len;
+	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 = IVAL(ndx_ptr, 0);
+	return rsync_xal_set(fname, lst + ndx); /* TODO:  This needs to return 1 if no xattrs changed! */
+}
+
+#endif /* SUPPORT_XATTRS */