lrdpv2: Ensure that QTF parsing is thread-safe

The debug_image_v2 module's usage of QTF to extract Ftrace log
information currently relies on a single QTF server process, and
communicates with that server process via a fixed port ID. Any other
instances of the ramdump parser running in parallel will also use
this same server and port ID, which presents a race condition if
multiple instances attempt to parse QTF input files simultaneously.

To deal with this problem, each ramdump parser instance must instead
create and communicate with its own QTF server process via a unique
port ID.

Change-Id: Ic9c53003789dca229d1e2770d01aa15a702292a7

linux-ramdump-parser-v2/debug_image_v2.py

@@ -15,8 +15,10 @@ import re
 import shutil
 import os
 import platform
+import random
 import subprocess
 import sys
+import time
 
 from dcc import DccRegDump, DccSramDump
 from pmic import PmicRegDump
@@ -288,14 +290,38 @@ class DebugImage_v2():
         else:
             return
 
-        port = 12345
+        port = None
+        server_proc = None
+        qtf_success = False
+        max_tries = 3
         qtf_dir = os.path.join(out_dir, 'qtf')
         workspace = os.path.join(qtf_dir, 'qtf.workspace')
         qtf_out = os.path.join(out_dir, 'qtf.txt')
         chipset = 'msm' + str(ram_dump.hw_id)
         hlos = 'LA'
 
-        p = subprocess.Popen([qtf_path, '-s', '{0}'.format(port)])
+        # Resolve any port collisions with other running qtf_server instances
+        for tries in range(max_tries):
+            port = random.randint(12000, 13000)
+            server_proc = subprocess.Popen(
+                [qtf_path, '-s', '{0}'.format(port)], stderr=subprocess.PIPE)
+            time.sleep(1)
+            server_proc.poll()
+            if server_proc.returncode == 1:
+                server_proc.terminate()
+                continue
+            else:
+                qtf_success = True
+                break
+        if not qtf_success:
+            server_proc.terminate()
+            print_out_str('!!! Could not open a QTF server instance with a '
+                          'unique port (last port tried: '
+                          '{0})'.format(str(port)))
+            print_out_str('!!! Please kill all currently running qtf_server '
+                          'processes and try again')
+            return
+
         subprocess.call('{0} -c {1} new workspace {2} {3} {4}'.format(qtf_path, port, qtf_dir, chipset, hlos))
 
         self.collect_ftrace_format(ram_dump)
@@ -303,8 +329,9 @@ class DebugImage_v2():
         subprocess.call('{0} -c {1} open workspace {2}'.format(qtf_path, port, workspace))
         subprocess.call('{0} -c {1} open bin {2}'.format(qtf_path, port, trace_file))
         subprocess.call('{0} -c {1} stream trace table {2}'.format(qtf_path, port, qtf_out))
+        subprocess.call('{0} -c {1} close'.format(qtf_path, port))
         subprocess.call('{0} -c {1} exit'.format(qtf_path, port))
-        p.communicate('quit')
+        server_proc.communicate('quit')
 
     def parse_dcc(self, ram_dump):
         out_dir = ram_dump.outdir