Improve gdbclient pid handling

Improves attaching to multi-process applications, connecting to the root process
if child process not specified instead of passing bad data to gdbserver

Also logs error instead of passing bad data to gdbserver if pid undetermined

Change-Id: I68ad62645c4f0a7a24aef02c84e3b5b84e14461e

envsetup.sh

@@ -776,13 +776,24 @@ function gdbclient()
            PORT=":5039"
        fi
 
-       local PID
-       local PROG="$3"
-       if [ "$PROG" ] ; then
-           if [[ "$PROG" =~ ^[0-9]+$ ]] ; then
-               PID="$3"
-           else
+       local PID="$3"
+       if [ "$PID" ] ; then
+           if [[ ! "$PID" =~ ^[0-9]+$ ]] ; then
                PID=`pid $3`
+               if [[ ! "$PID" =~ ^[0-9]+$ ]] ; then
+                   # that likely didn't work because of returning multiple processes
+                   # try again, filtering by root processes (don't contain colon)
+                   PID=`adb shell ps | grep $3 | grep -v ":" | awk '{print $2}'`
+                   if [[ ! "$PID" =~ ^[0-9]+$ ]]
+                   then
+                       echo "Couldn't resolve '$3' to single PID"
+                       return 1
+                   else
+                       echo ""
+                       echo "WARNING: multiple processes matching '$3' observed, using root process"
+                       echo ""
+                   fi
+               fi
            fi
            adb forward "tcp$PORT" "tcp$PORT"
            adb shell gdbserver $PORT --attach $PID &
@@ -792,7 +803,7 @@ function gdbclient()
                echo "If you haven't done so already, do this first on the device:"
                echo "    gdbserver $PORT /system/bin/$EXE"
                    echo " or"
-               echo "    gdbserver $PORT --attach $PID"
+               echo "    gdbserver $PORT --attach <PID>"
                echo ""
        fi