Better generation of random names for reply FIFO.

Related to issue #257

scripts/opensipsctl.fifo

@@ -50,8 +50,7 @@ fifo_cmd()
 		merr "fifo_cmd must take at least command name as parameter"
 		exit 1
 	fi
-	name=opensips_receiver_$$
-	path=$CHROOT_DIR/tmp/$name
+
 	if [ ! -w $OSIPS_FIFO ]; then
 		merr "Error opening OpenSIPS's FIFO $OSIPS_FIFO"
 		merr "Make sure you have the line 'modparam(\"mi_fifo\", \"fifo_name\", \"$OSIPS_FIFO\")' in your config"
@@ -61,14 +60,15 @@ fifo_cmd()
 		fi
 		exit 2
 	fi
-	if ! test -p $path; then
-		mkfifo $path
-		if [ $? -ne 0 ] ; then
-			merr "error opening read fifo $path"
-			exit 3
-		fi
-		chmod a+w $path
-	fi
+
+	# generate a random and unique filename
+	while :
+	do
+		suffix=$(od -An -N4 -tx4 /dev/urandom  | tr -d " ")
+		(mkfifo --mode=a+w $CHROOT_DIR/tmp/osips_rply_$suffix) &>/dev/null && break
+	done
+	name=osips_rply_$suffix
+	path=$CHROOT_DIR/tmp/$name
 
 	# construct the command now
 	CMD=":$1:$name\n";