Fix tests when running on Win10

The Windows 10 loader starts a few extra threads before main(). In a few
of the test cases, the tests were relying on thread ordering (generally,
the test thread being at index #1). Instead, use other signals to find
the correct thread to verify.

R=mark@chromium.org

Change-Id: Icb1f5a8fdf3a0ea6d82ab65960dbcb650965f269
Reviewed-on: https://chromium-review.googlesource.com/407073
Reviewed-by: Mark Mentovai <mark@chromium.org>

handler/win/crash_other_program.cc

@@ -46,13 +46,13 @@ bool CrashAndDumpTarget(const CrashpadClient& client, HANDLE process) {
     return false;
   }
 
-  int thread_count = 0;
   do {
     if (te32.th32OwnerProcessID == target_pid) {
-      thread_count++;
-      if (thread_count == 2) {
-        // Nominate this lucky thread as our blamee, and dump it. This will be
-        // "Thread1" in the child.
+      // We set the thread priority of "Thread1" to a non-default value before
+      // going to sleep. Dump and blame this thread. For an explanation of
+      // "9", see
+      // https://msdn.microsoft.com/en-us/library/windows/desktop/ms685100.aspx.
+      if (te32.tpBasePri == 9) {
         ScopedKernelHANDLE thread(
             OpenThread(kXPThreadAllAccess, false, te32.th32ThreadID));
         if (!client.DumpAndCrashTargetProcess(

handler/win/hanging_program.cc

@@ -22,6 +22,9 @@
 #include "client/crashpad_info.h"
 
 DWORD WINAPI Thread1(LPVOID dummy) {
+  // We set the thread priority up by one as a hacky way to signal to the other
+  // test program that this is the thread we want to dump.
+  SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_ABOVE_NORMAL);
   Sleep(INFINITE);
   return 0;
 }

snapshot/win/end_to_end_test.py

@@ -185,6 +185,14 @@ class CdbRun(object):
       global g_had_failures
       g_had_failures = True
 
+  def Find(self, pattern, re_flags=0):
+    match_obj = re.search(pattern, self.out, re_flags)
+    if match_obj:
+      # Matched. Consume up to end of match.
+      self.out = self.out[match_obj.end(0):]
+      return match_obj
+    return None
+
 
 def RunTests(cdb_path,
              dump_path,
@@ -267,9 +275,15 @@ def RunTests(cdb_path,
                 r'FreeOwnStackAndBreak.*\nquit:',
             'at correct location, no additional stack entries')
 
-  # Switch to the other thread after jumping to the exception, and examine
-  # memory.
-  out = CdbRun(cdb_path, dump_path, '.ecxr; ~1s; db /c14 edi')
+  # Dump memory pointed to be EDI on the background suspended thread. We don't
+  # know the index of the thread because the system may have started other
+  # threads, so first do a run to extract the thread index that's suspended, and
+  # then another run to dump the data pointed to by EDI for that thread.
+  out = CdbRun(cdb_path, dump_path, '.ecxr;~')
+  match_obj = out.Find(r'(\d+)\s+Id: [0-9a-f.]+ Suspend: 1 Teb:')
+  if match_obj:
+    thread = match_obj.group(1)
+    out = CdbRun(cdb_path, dump_path, '.ecxr;~' + thread + 's;db /c14 edi')
   out.Check(r'63 62 61 60 5f 5e 5d 5c-5b 5a 59 58 57 56 55 54 53 52 51 50',
             'data pointed to by registers captured')
 
@@ -330,10 +344,17 @@ def RunTests(cdb_path,
             'other program dump exception code')
   out.Check('!Sleep', 'other program reasonable location')
   out.Check('hanging_program!Thread1', 'other program dump right thread')
-  out.Check('\.  1  Id.*Suspend: 0 ',
-            'other program exception on correct thread and correct suspend')
-  out.Check('   4  Id.*Suspend: 0 ',
-            'other program injection thread correct suspend')
+  count = 0
+  while True:
+    match_obj = out.Find(r'Id.*Suspend: (\d+) ')
+    if match_obj:
+      if match_obj.group(1) != '0':
+        out.Check(r'FAILED', 'all suspend counts should be 0')
+      else:
+        count += 1
+    else:
+      break
+  assert count > 2
 
   out = CdbRun(cdb_path, other_program_no_exception_path, '.ecxr;k')
   out.Check('Unknown exception - code 0cca11ed',