Fixed some issues with signal handling and cleanup.

Fixed several issues related to signal handling and cleanup:
- Got rid of the extra process wrapper around crosperf. We now do an
"exec" to get rid of this extra process. This facilitated signal
handling.
- Found a better fix for the problem we had with ignoring
ctrl-c. Instead of creating a pipe for child process stdin, we now
create the child with setsid which has the side effect of creating the
child without a terminal associated to it (see man setsid).
- By creating the child with setsid, we also allow for easier killing of
the child and its descendants since it allows us to use killpg (see man
killpg).
- Handle SIGTERM by "converting" it into an exit call. This will make
sure the atexit routines are called and, furthermore, we can terminate
child process when you catch the "SystemExit" exception.
- With these changes, crosperf will send a SIGTERM to any cros_sdk,
test_that processes that it has started. Before, we would have left over
test_that processes that could interfere with a new test_that
invocation.

BUG=chromium:492826
BUG=chromium:470658
TEST=verified by hand signals are working. Ran toolchain suite.

Change-Id: Ibd09ff428a7b402ea2296ecf9b9a34aa5756c93f
Reviewed-on: https://chrome-internal-review.googlesource.com/232616
Commit-Ready: Luis Lozano <llozano@chromium.org>
Tested-by: Luis Lozano <llozano@chromium.org>
Reviewed-by: Yunlian Jiang <yunlian@google.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/crosperf/crosperf.py b/crosperf/crosperf.py
index fc0098d2..e107ea48 100755
--- a/crosperf/crosperf.py
+++ b/crosperf/crosperf.py
@@ -7,6 +7,7 @@
 import atexit
 import optparse
 import os
+import signal
 import sys
 from experiment_runner import ExperimentRunner
 from experiment_runner import MockExperimentRunner
@@ -58,6 +59,16 @@ def Cleanup(experiment):
   experiment.Cleanup()
 
 
+def CallExitHandler(signum, _):
+  """Signal handler that transforms a signal into a call to exit.
+
+  This is useful because functionality registered by "atexit" will
+  be called. It also means you can "catch" the signal by catching
+  the SystemExit exception.
+  """
+  sys.exit(128 + signum)
+
+
 def Main(argv):
   parser = optparse.OptionParser(usage=Help().GetUsage(),
                                  description=Help().GetHelp(),
@@ -104,6 +115,7 @@ def Main(argv):
 
   json_report = experiment_file.GetGlobalSettings().GetField("json_report")
 
+  signal.signal(signal.SIGTERM, CallExitHandler)
   atexit.register(Cleanup, experiment)
 
   if options.dry_run: