slp.diff

This adds Service Location Protocol support.

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

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

TODO: the configure changes should abort if the user requests --enable-slp
and we can't honor that request.

based-on: 6c8ca91c731b7bf2b081694bda85b7dadc2b7aff
diff --git a/Makefile.in b/Makefile.in
--- a/Makefile.in
+++ b/Makefile.in
@@ -17,6 +17,8 @@ CXX=@CXX@
 CXXFLAGS=@CXXFLAGS@
 EXEEXT=@EXEEXT@
 LDFLAGS=@LDFLAGS@
+LIBSLP=@LIBSLP@
+SLPOBJ=@SLPOBJ@
 LIBOBJDIR=lib/
 
 INSTALLCMD=@INSTALL@
@@ -48,7 +50,7 @@ OBJS1=flist.o rsync.o generator.o receiver.o cleanup.o sender.o exclude.o \
 OBJS2=options.o io.o compat.o hlink.o token.o uidlist.o socket.o hashtable.o \
 	usage.o fileio.o batch.o clientname.o chmod.o acls.o xattrs.o
 OBJS3=progress.o pipe.o @MD5_ASM@ @ROLL_SIMD@ @ROLL_ASM@
-DAEMON_OBJ = params.o loadparm.o clientserver.o access.o connection.o authenticate.o
+DAEMON_OBJ = params.o loadparm.o clientserver.o access.o connection.o authenticate.o $(SLPOBJ)
 popt_OBJS=popt/findme.o  popt/popt.o  popt/poptconfig.o \
 	popt/popthelp.o popt/poptparse.o
 OBJS=$(OBJS1) $(OBJS2) $(OBJS3) $(DAEMON_OBJ) $(LIBOBJ) @BUILD_ZLIB@ @BUILD_POPT@
@@ -103,7 +105,7 @@ install-strip:
 	$(MAKE) INSTALL_STRIP='-s' install
 
 rsync$(EXEEXT): $(OBJS)
-	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS) $(LIBSLP)
 
 rrsync: support/rrsync
 	cp -p $(srcdir)/support/rrsync rrsync
diff --git a/clientserver.c b/clientserver.c
--- a/clientserver.c
+++ b/clientserver.c
@@ -1533,6 +1533,13 @@ int daemon_main(void)
 	 * address too.  In fact, why not just do getnameinfo on the
 	 * local address??? */
 
+#ifdef HAVE_LIBSLP
+	if (lp_use_slp() && register_services()) {
+		rprintf(FINFO,
+		    "Couldn't register with service discovery protocol, continuing anyway\n");
+	}
+#endif
+
 	start_accept_loop(rsync_port, start_daemon);
 	return -1;
 }
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -1047,6 +1047,29 @@ if test $rsync_cv_can_hardlink_special = yes; then
     AC_DEFINE(CAN_HARDLINK_SPECIAL, 1, [Define to 1 if link() can hard-link special files.])
 fi
 
+AC_ARG_ENABLE(slp, [  --disable-slp           turn off SLP support, defaults to on])
+AC_ARG_WITH(openslp-libs, [  --with-openslp-libs     set directory for OpenSLP library],
+    LDFLAGS="-L$withval $LDFLAGS"
+    DSOFLAGS="-L$withval $DSOFLAGS",)
+AC_ARG_WITH(openslp-includes, [  --with-openslp-includes set directory for OpenSLP includes],
+    CFLAGS="-I$withval $CFLAGS"
+    CXXFLAGS="-I$withval $CXXFLAGS"
+    CPPFLAGS="-I$withval $CPPFLAGS",)
+
+LIBSLP=""
+SLPOBJ=""
+
+if test x$enable_slp != xno; then
+    AC_CHECK_HEADER(slp.h,
+        AC_CHECK_LIB(slp, SLPOpen,
+	    AC_DEFINE(HAVE_LIBSLP, 1, [Define to 1 for SLP support])
+	    SLPOBJ="srvreg.o srvloc.o"
+            LIBSLP="-lslp"))
+fi
+
+AC_SUBST(LIBSLP)
+AC_SUBST(SLPOBJ)
+
 AC_CACHE_CHECK([for working socketpair],rsync_cv_HAVE_SOCKETPAIR,[
 AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #ifdef HAVE_SYS_TYPES_H
diff --git a/daemon-parm.txt b/daemon-parm.txt
--- a/daemon-parm.txt
+++ b/daemon-parm.txt
@@ -10,8 +10,10 @@ STRING	socket_options		NULL
 
 INTEGER	listen_backlog		5
 INTEGER	rsync_port|port		0
+INTEGER	slp_refresh		0
 
 BOOL	proxy_protocol		False
+BOOL	use_slp			False
 
 Locals: =================================================================
 
diff --git a/main.c b/main.c
--- a/main.c
+++ b/main.c
@@ -1400,6 +1400,22 @@ static int start_client(int argc, char *argv[])
 
 	if (!read_batch) { /* for read_batch, NO source is specified */
 		char *path = check_for_hostspec(argv[0], &shell_machine, &rsync_port);
+
+		if (shell_machine && !shell_machine[0]) {
+#ifdef HAVE_LIBSLP
+			/* User entered just rsync:// URI */
+			if (lp_use_slp()) {
+				print_service_list();
+				exit_cleanup(0);
+			}
+			rprintf(FINFO, "SLP is disabled, cannot browse\n");
+			exit_cleanup(RERR_SYNTAX);
+#else /* No SLP, die here */
+			rprintf(FINFO, "No SLP support, cannot browse\n");
+			exit_cleanup(RERR_SYNTAX);
+#endif
+		}
+
 		if (path) { /* source is remote */
 			char *dummy_host;
 			int dummy_port = 0;
diff --git a/rsync.1.md b/rsync.1.md
--- a/rsync.1.md
+++ b/rsync.1.md
@@ -152,6 +152,18 @@ rsync daemon by leaving off the module name:
 
 >     rsync somehost.mydomain.com::
 
+And, if Service Location Protocol is available, the following will list the
+available rsync servers:
+
+>     rsync rsync://
+
+See the following section for even more usage details.
+
+One more thing, if Service Location Protocol is available, the following will
+list the available rsync servers:
+
+>     rsync rsync://
+
 ## COPYING TO A DIFFERENT NAME
 
 When you want to copy a directory to a different name, use a trailing slash on
diff --git a/rsync.h b/rsync.h
--- a/rsync.h
+++ b/rsync.h
@@ -234,6 +234,10 @@
 #define SIGNIFICANT_ITEM_FLAGS (~(\
 	ITEM_BASIS_TYPE_FOLLOWS | ITEM_XNAME_FOLLOWS | ITEM_LOCAL_CHANGE))
 
+/* this is the minimum we'll use, irrespective of config setting */
+/* definitely don't set to less than about 30 seconds */
+#define SLP_MIN_TIMEOUT 120
+
 #define CFN_KEEP_DOT_DIRS (1<<0)
 #define CFN_KEEP_TRAILING_SLASH (1<<1)
 #define CFN_DROP_TRAILING_DOT_DIR (1<<2)
diff --git a/rsyncd.conf b/rsyncd.conf
new file mode 100644
--- /dev/null
+++ b/rsyncd.conf
@@ -0,0 +1 @@
+slp refresh = 300
diff --git a/rsyncd.conf.5.md b/rsyncd.conf.5.md
--- a/rsyncd.conf.5.md
+++ b/rsyncd.conf.5.md
@@ -120,6 +120,21 @@ parameters:
     You can override the default backlog value when the daemon listens for
     connections.  It defaults to 5.
 
+0.  `use slp`
+
+    You can enable Service Location Protocol support by enabling this global
+    parameter.  The default is "false".
+
+0.  `slp refresh`
+
+    This parameter is used to determine how long service advertisements are
+    valid (measured in seconds), and is only applicable if you have Service
+    Location Protocol support compiled in. If this is not set or is set to
+    zero, then service advertisements never time out. If this is set to less
+    than 120 seconds, then 120 seconds is used. If it is set to more than
+    65535, then 65535 is used (which is a limitation of SLP).  Using 3600
+    (one hour) is a good number if you tend to change your configuration.
+
 You may also include any [MODULE PARAMETERS](#) in the global part of the
 config file, in which case the supplied value will override the default for
 that parameter.
@@ -1208,6 +1223,7 @@ A more sophisticated example would be:
 > max connections = 4
 > syslog facility = local5
 > pid file = /var/run/rsyncd.pid
+> slp refresh = 3600
 >
 > [ftp]
 >         path = /var/ftp/./pub
diff --git a/socket.c b/socket.c
--- a/socket.c
+++ b/socket.c
@@ -534,6 +534,16 @@ void start_accept_loop(int port, int (*fn)(int, int))
 {
 	fd_set deffds;
 	int *sp, maxfd, i;
+#ifdef HAVE_LIBSLP
+	time_t next_slp_refresh;
+	short slp_timeout = lp_use_slp() ? lp_slp_refresh() : 0;
+	if (slp_timeout) {
+		if (slp_timeout < SLP_MIN_TIMEOUT)
+			slp_timeout = SLP_MIN_TIMEOUT;
+		/* re-register before slp times out */
+		slp_timeout -= 15;
+	}
+#endif
 
 #ifdef HAVE_SIGACTION
 	sigact.sa_flags = SA_NOCLDSTOP;
@@ -561,14 +571,25 @@ void start_accept_loop(int port, int (*fn)(int, int))
 			maxfd = sp[i];
 	}
 
+#ifdef HAVE_LIBSLP
+	next_slp_refresh = time(NULL) + slp_timeout;
+#endif
+
 	/* now accept incoming connections - forking a new process
 	 * for each incoming connection */
 	while (1) {
 		fd_set fds;
 		pid_t pid;
 		int fd;
+		int sel_ret;
 		struct sockaddr_storage addr;
 		socklen_t addrlen = sizeof addr;
+#ifdef HAVE_LIBSLP
+		struct timeval slp_tv;
+
+		slp_tv.tv_sec = 10;
+		slp_tv.tv_usec = 0;
+#endif
 
 		/* close log file before the potentially very long select so
 		 * file can be trimmed by another process instead of growing
@@ -581,7 +602,18 @@ void start_accept_loop(int port, int (*fn)(int, int))
 		fds = deffds;
 #endif
 
-		if (select(maxfd + 1, &fds, NULL, NULL, NULL) < 1)
+#ifdef HAVE_LIBSLP
+		sel_ret = select(maxfd + 1, &fds, NULL, NULL,
+				 slp_timeout ? &slp_tv : NULL);
+		if (sel_ret == 0 && slp_timeout && time(NULL) > next_slp_refresh) {
+			rprintf(FINFO, "Service registration expired, refreshing it\n");
+			register_services();
+			next_slp_refresh = time(NULL) + slp_timeout;
+		}
+#else
+		sel_ret = select(maxfd + 1, &fds, NULL, NULL, NULL);
+#endif
+		if (sel_ret < 1)
 			continue;
 
 		for (i = 0, fd = -1; sp[i] >= 0; i++) {
diff --git a/srvloc.c b/srvloc.c
new file mode 100644
--- /dev/null
+++ b/srvloc.c
@@ -0,0 +1,103 @@
+/* -*- c-file-style: "linux"; -*-
+
+   Copyright (C) 2002 by Brad Hards <bradh@frogmouth.net>
+
+   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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/* This file implements the service location functionality */
+/* Basically, it uses normal Service Location Protocol API */
+
+/* It is really a cheap hack - just to show how it might work
+   in a real application.
+*/
+
+#include "rsync.h"
+
+#include <slp.h>
+#include <stdio.h>
+#include <string.h>
+
+/* This one just prints out the attributes */
+static SLPBoolean getAttrCallback(UNUSED(SLPHandle hslp), const char *attrlist,
+				  SLPError errcode, UNUSED(void *cookie))
+{
+	char *cleanstr;
+
+	if (errcode == SLP_OK) {
+		if (!strcmp(attrlist, "(comment=)"))
+			rprintf(FINFO, "\t(No description)\n");
+		else {
+			cleanstr = strrchr(attrlist, ')') ;
+			*cleanstr = ' '; /* remove last ')' */
+			rprintf(FINFO, "\t%s\n", strchr(attrlist, '=') + 1);
+		}
+	}
+	return SLP_FALSE;
+}
+
+static SLPBoolean getSLPSrvURLCallback(UNUSED(SLPHandle hslp),
+			const char *srvurl, UNUSED(unsigned short lifetime),
+			SLPError errcode, void *cookie)
+{
+	SLPError    result;
+	SLPHandle   attrhslp;
+
+	if (errcode == SLP_OK) {
+		/* chop service: off the front */
+		rprintf(FINFO, "  %s  ", (strchr(srvurl, ':') + 1));
+		/* check for any attributes */
+		if (SLPOpen("en", SLP_FALSE,&attrhslp) == SLP_OK) {
+			result = SLPFindAttrs(attrhslp, srvurl,
+					      "", /* return all attributes */
+					      "", /* use configured scopes */
+					      getAttrCallback, NULL);
+			if (result != SLP_OK) {
+				rprintf(FERROR, "errorcode: %i\n",result);
+			}
+			SLPClose(attrhslp);
+		}
+		*(SLPError*)cookie = SLP_OK;
+	} else
+		*(SLPError*)cookie = errcode;
+
+	/* Return SLP_TRUE because we want to be called again
+	 * if more services were found. */
+
+	return SLP_TRUE;
+}
+
+int print_service_list(void)
+{
+	SLPError err;
+	SLPError callbackerr;
+	SLPHandle hslp;
+
+	err = SLPOpen("en",SLP_FALSE,&hslp);
+	if (err != SLP_OK) {
+		rprintf(FERROR, "Error opening slp handle %i\n", err);
+		return err;
+	}
+
+	SLPFindSrvs(hslp, "rsync",
+		    0, /* use configured scopes */
+		    0, /* no attr filter        */
+		    getSLPSrvURLCallback, &callbackerr);
+
+	/* Now that we're done using slp, close the slp handle */
+	SLPClose(hslp);
+
+	return 0;
+}
diff --git a/srvreg.c b/srvreg.c
new file mode 100644
--- /dev/null
+++ b/srvreg.c
@@ -0,0 +1,128 @@
+/* -*- c-file-style: "linux"; -*-
+
+   Copyright (C) 2002 by Brad Hards <bradh@frogmouth.net>
+
+   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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/* This file implements the service registration functionality */
+
+/* Basically, it uses normal Service Location Protocol API */
+
+#include "rsync.h"
+#include "slp.h"
+#include "netdb.h"
+
+extern int rsync_port;
+
+static void slp_callback(UNUSED(SLPHandle hslp), SLPError errcode, void *cookie)
+{
+	/* return the error code in the cookie */
+	*(SLPError*)cookie = errcode;
+
+	/* You could do something else here like print out
+	 * the errcode, etc.  Remember, as a general rule,
+	 * do not try to do too much in a callback because
+	 * it is being executed by the same thread that is
+	 * reading slp packets from the wire. */
+}
+
+int register_services(void)
+{
+	SLPError err, callbackerr;
+	SLPHandle hslp;
+	int n;
+	int i;
+	char srv[120];
+	char attr[120];
+	char localhost[256];
+	extern char *config_file;
+	short timeout;
+	struct addrinfo aih, *ai = 0;
+
+	if (!lp_load(config_file, 0)) {
+		exit_cleanup(RERR_SYNTAX);
+	}
+
+	n = lp_num_modules();
+
+	if (0 == lp_slp_refresh())
+		timeout = SLP_LIFETIME_MAXIMUM; /* don't expire, ever */
+	else if (SLP_MIN_TIMEOUT > lp_slp_refresh())
+		timeout = SLP_MIN_TIMEOUT; /* use a reasonable minimum */
+	else if (SLP_LIFETIME_MAXIMUM <= lp_slp_refresh())
+		timeout = (SLP_LIFETIME_MAXIMUM - 1); /* as long as possible */
+	else
+		timeout = lp_slp_refresh();
+
+	rprintf(FINFO, "rsyncd registering %d service%s with slpd for %d seconds:\n", n, ((n==1)? "":"s"), timeout);
+	err = SLPOpen("en",SLP_FALSE,&hslp);
+	if (err != SLP_OK) {
+		rprintf(FINFO, "Error opening slp handle %i\n",err);
+		return err;
+	}
+	if (gethostname(localhost, sizeof localhost)) {
+	       rprintf(FINFO, "Could not get hostname: %s\n", strerror(errno));
+	       return err;
+	}
+	memset(&aih, 0, sizeof aih);
+	aih.ai_family = PF_UNSPEC;
+	aih.ai_flags = AI_CANONNAME;
+	if (0 != (err = getaddrinfo(localhost, 0, &aih, &ai)) || !ai) {
+	       rprintf(FINFO, "Could not resolve hostname: %s\n", gai_strerror(err));
+	       return err;
+	}
+	/* Register each service with SLP */
+	for (i = 0; i < n; i++) {
+		if (!lp_list(i))
+			continue;
+
+		snprintf(srv, sizeof srv, "service:rsync://%s:%d/%s",
+			 ai->ai_canonname,
+			 rsync_port,
+			 lp_name(i));
+		rprintf(FINFO, "    %s\n", srv);
+		if (lp_comment(i)) {
+			snprintf(attr, sizeof attr, "(comment=%s)",
+				 lp_comment(i));
+		}
+		err = SLPReg(hslp,
+			     srv, /* service to register */
+			     timeout,
+			     0,  /* this is ignored */
+			     attr, /* attributes */
+			     SLP_TRUE, /* new registration - don't change this */
+			     slp_callback, /* callback */
+			     &callbackerr);
+
+		/* err may contain an error code that occurred as the slp library
+		 * _prepared_ to make the call. */
+		if (err != SLP_OK || callbackerr != SLP_OK)
+			rprintf(FINFO, "Error registering service with slp %i\n", err);
+
+		/* callbackerr may contain an error code (that was assigned through
+		 * the callback cookie) that occurred as slp packets were sent on
+		 * the wire. */
+		if (callbackerr != SLP_OK)
+			rprintf(FINFO, "Error registering service with slp %i\n",callbackerr);
+	}
+
+	/* Now that we're done using slp, close the slp handle */
+	freeaddrinfo(ai);
+	SLPClose(hslp);
+
+	/* refresh is done in main select loop */
+	return 0;
+}
diff --git a/usage.c b/usage.c
--- a/usage.c
+++ b/usage.c
@@ -138,6 +138,11 @@ static void print_info_flags(enum logcode f)
 #endif
 			"crtimes",
 
+#ifndef HAVE_LIBSLP
+		"no "
+#endif
+			"SLP",
+
 	"*Optimizations",
 
 #ifndef USE_ROLL_SIMD