Merge "Improve logging in winscope_proxy.py" into udc-dev

tools/winscope/src/adb/winscope_proxy.py

@@ -646,10 +646,15 @@ echo "TRACE_START" > /data/local/tmp/winscope_status
 
 # Do not print anything to stdout/stderr in the handler
 function stop_trace() {{
+  echo "start" >/data/local/tmp/winscope_signal_handler.log
+
+  # redirect stdout/stderr to log file
+  exec 1>>/data/local/tmp/winscope_signal_handler.log
+  exec 2>>/data/local/tmp/winscope_signal_handler.log
+
+  set -x
   trap - EXIT HUP INT
-
+  {}
-{}
-
   echo "TRACE_OK" > /data/local/tmp/winscope_status
 }}
 
@@ -695,8 +700,18 @@ class EndTrace(DeviceRequestEndpoint):
             TRACE_THREADS[device_id].end_trace()
 
         success = TRACE_THREADS[device_id].success()
-        out = TRACE_THREADS[device_id].out + \
+
-            b"\n" + TRACE_THREADS[device_id].err
+        signal_handler_log = call_adb("shell su root cat /data/local/tmp/winscope_signal_handler.log", device=device_id).encode('utf-8')
+
+        out = b"### Shell script's stdout - start\n" + \
+            TRACE_THREADS[device_id].out + \
+            b"### Shell script's stdout - end\n" + \
+            b"### Shell script's stderr - start\n" + \
+            TRACE_THREADS[device_id].err + \
+            b"### Shell script's stderr - end\n" + \
+            b"### Signal handler log - start\n" + \
+            signal_handler_log + \
+            b"### Signal handler log - end\n"
         command = TRACE_THREADS[device_id].trace_command
         TRACE_THREADS.pop(device_id)
         if success: