test-runner: add option to write final status to file

Running the tests inside a VM makes it difficult for the host to figure
out if the test actually failed or succeeded. For a human its easy to
read the results table, but for an automated system parsing this would
be fragile. This adds a new option --result <file> which writes PASS/FAIL
to the provided file once all tests are completed. Any failures results in
'FAIL' being written to the file.

tools/test-runner

@@ -62,7 +62,14 @@ def exit_vm():
 			p.kill()
 
 	if config.ctx and config.ctx.results:
-		print_results(config.ctx.results)
+		success = print_results(config.ctx.results)
+	else:
+		success = False
+
+	if config.ctx.args.result:
+		result = 'PASS' if success else 'FAIL'
+		with open(config.ctx.args.result, 'w') as f:
+			f.write(result)
 
 	os.sync()
 
@@ -1434,6 +1441,8 @@ def print_results(results):
 
 	dbg(table)
 
+	return total_fail == 0
+
 def run_auto_tests(ctx, args):
 	tests = build_test_list(args)
 
@@ -1528,6 +1537,7 @@ def run_tests():
 	parser.add_argument('--hw')
 	parser.add_argument('--monitor')
 	parser.add_argument('--sub_tests')
+	parser.add_argument('--result')
 
 	args = parser.parse_args(options)
 
@@ -1580,6 +1590,10 @@ def run_tests():
 		parent = os.path.abspath(os.path.join(args.monitor, os.pardir))
 		mount('mondir', parent, '9p', 0, 'trans=virtio,version=9p2000.L,msize=10240')
 
+	if args.result:
+		parent = os.path.abspath(os.path.join(args.result, os.pardir))
+		mount('resultdir', parent, '9p', 0, 'trans=virtio,version=9p2000.L,msize=10240')
+
 	if config.ctx.args.unit_tests is None:
 		run_auto_tests(config.ctx, args)
 	else:
@@ -1620,6 +1634,8 @@ class Main:
 		self.parser.add_argument('--sub-tests', '-S', metavar='<subtests>',
 				type=str, nargs=1, help='List of subtests to run',
 				default=None, dest='sub_tests')
+		self.parser.add_argument('--result', '-r', type=str,
+				help='Writes PASS/FAIL to results file')
 
 		# Prevent --autotest/--unittest from being used together
 		auto_unit_group = self.parser.add_mutually_exclusive_group()
@@ -1767,6 +1783,20 @@ class Main:
 			options += ' --log-gid %u' % int(os.environ['SUDO_GID'])
 			options += ' --log-uid %u' % int(os.environ['SUDO_UID'])
 
+		if self.args.result:
+			if os.environ.get('SUDO_GID', None) is None:
+				print("--result can only be used as root user")
+				quit()
+
+			self.args.result = os.path.abspath(self.args.result)
+			result_parent_dir = os.path.abspath(os.path.join(self.args.result, os.pardir))
+
+			if '--log-gid' not in options:
+				options += ' --log-gid %u' % int(os.environ['SUDO_GID'])
+
+			if '--log-uid' not in options:
+				options += ' --log-uid %u' % int(os.environ['SUDO_UID'])
+
 		denylist = [
 			'auto_tests',
 			'sub_tests',
@@ -1873,6 +1903,13 @@ class Main:
 						% mon_parent_dir
 			])
 
+		if self.args.result:
+			qemu_cmdline.extend([
+				'-virtfs',
+				'local,path=%s,mount_tag=resultdir,security_model=passthrough,id=resultdir' \
+						% result_parent_dir
+			])
+
 		os.execlp(qemu_cmdline[0], *qemu_cmdline)
 
 if __name__ == '__main__':