client-server: improve random port selection and mdns txt use

3 files changed, 19 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index 88497aef..88de8c62 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2008-08-06  Frank Ch. Eigler  <fche@elastic.org>
+
+	* stap-find-servers (match_server, client_sysinfo):
+	Use "sysinfo=...." keyword in mdns TXT record.
+	* stap-serverd (advertise_presence): Ditto.
+	(initialization): Locate random usable server port if needed.
+	(listen): Complain if port turns out to be unusable after all.
+
 2008-08-06  Josh Stone  <joshua.i.stone@intel.com>
 
 	PR 6820
diff --git a/stap-find-servers b/stap-find-servers
index 9e7b633d..fea645bd 100755
--- a/stap-find-servers
+++ b/stap-find-servers
@@ -87,7 +87,7 @@ function match_server {
 		    server_port=`expr "$service_data" : '\[\([^]]*\)\]'`
 		    ;;
 		txt )
-		    server_sysinfo=`expr "$service_data" : '\[\"\([^]]*\)\"\]'`
+		    server_sysinfo=`expr "$service_data" : '\[.*\"\(sysinfo=[^]]*\)\"\]'`
 		    ;;
 		* )
 		    break ;;
@@ -115,7 +115,7 @@ function client_sysinfo {
 	# Add some info from uname
 	sysinfo_client="`uname -rvm`"
     fi
-    echo $sysinfo_client
+    echo sysinfo=$sysinfo_client
 }
 
 #-----------------------------------------------------------------------------
diff --git a/stap-serverd b/stap-serverd
index af4b2717..6170eb8f 100755
--- a/stap-serverd
+++ b/stap-serverd
@@ -26,6 +26,11 @@ function initialization {
     avahi_type=_stap._tcp
     port=$1
     test "X$port" = "X" && port=65000
+    port2=$(($port + 1))
+    if netstat -atn | awk '{print $4}' | cut -f2 -d: | egrep -q "^($port|$port2)\$"; then
+        # Whoops, the port is busy; try another one.
+        initialization $((1024+($port + $RANDOM)%64000))
+    fi
 }
 
 # function: advertise_presence
@@ -35,7 +40,7 @@ function advertise_presence {
     # Build up a string representing our server's properties.
     # TODO: this needs fleshing out.
     local sysinfo=`uname -rvm`
-    local txt="$sysinfo"
+    local txt="sysinfo=$sysinfo"
 
     # Call avahi-publish-service to advertise our presence.
     avahi-publish-service "Systemtap Compile Server on `uname -n`" \
@@ -65,6 +70,9 @@ function listen {
 	# received (i.e. SIGTERM) will be processed.
 	nc -l $port < $fifo_name | stap-server $((port + 1)) > $fifo_name 2>&1 &
 	wait %nc
+        if [ $? -ne 0 ]; then
+            fatal "ERROR: cannot listen on port $port"
+        fi
     done
 }