Add automated tests for plugins

Test infrastructure and sample confs/rules/traces for plugins
automated tests:

New test cases are in falco_tests_plugins.yaml and cover:
- Listing plugins and fields when plugins are loaded.
- Basic cloudtrail + json plugin on a fake cloudtrail json file and a
  sample rule that uses both plugins.
- Conflicts between source/extractor plugins
- Incompatible plugin api
- Wrong plugin path
- Checking for warnings when reading rules with unnown sources (e.g. when plugins are not loaded)

Some test-only plugins written in C are in test/plugins and built on
the fly. (They aren't included in packages of course).

The test framework needed some small changes to handle these tests:
- Add a mode to not check detection counts at all (for --list/--list-plugins)
- addl_cmdline_opts to allow specifying --list/--list-plugins
- Using DOTALL when matching stderr/stdout (allows multi-line matches more easily)

Signed-off-by: Mark Stemm <mark.stemm@gmail.com>

test/trace_files/CMakeLists.txt

@@ -1,5 +1,6 @@
 add_subdirectory(k8s_audit)
 add_subdirectory(psp)
+add_subdirectory(plugins)
 
 # Note: list of traces is created at cmake time, not build time
 file(GLOB test_trace_files
@@ -16,4 +17,4 @@ foreach(trace_file_path ${test_trace_files})
 endforeach()
 
 add_custom_target(trace-files-base-scap ALL)
-add_dependencies(trace-files-base-scap ${BASE_SCAP_TRACE_FILES_TARGETS})
+add_dependencies(trace-files-base-scap ${BASE_SCAP_TRACE_FILES_TARGETS})

test/trace_files/plugins/CMakeLists.txt

@@ -0,0 +1,16 @@
+# Note: list of traces is created at cmake time, not build time
+file(GLOB test_trace_files
+	"${CMAKE_CURRENT_SOURCE_DIR}/*.json")
+
+foreach(trace_file_path ${test_trace_files})
+	get_filename_component(trace_file ${trace_file_path} NAME)
+	add_custom_target(test-trace-${trace_file} ALL
+		DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${trace_file})
+	add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${trace_file}
+		COMMAND ${CMAKE_COMMAND} -E copy ${trace_file_path} ${CMAKE_CURRENT_BINARY_DIR}/${trace_file}
+		DEPENDS ${trace_file_path})
+	list(APPEND PLUGINS_TRACE_FILES_TARGETS test-trace-${trace_file})
+endforeach()
+
+add_custom_target(trace-files-plugins ALL)
+add_dependencies(trace-files-plugins ${PLUGINS_TRACE_FILES_TARGETS})

test/trace_files/plugins/alice_start_instances.json

@@ -0,0 +1,31 @@
+{"Records": [{
+    "eventVersion": "1.0",
+    "userIdentity": {
+	"type": "IAMUser",
+	"principalId": "EX_PRINCIPAL_ID",
+	"arn": "arn:aws:iam::123456789012:user/Alice",
+	"accessKeyId": "EXAMPLE_KEY_ID",
+	"accountId": "123456789012",
+	"userName": "Alice"
+    },
+    "eventTime": "2014-03-06T21:22:54Z",
+    "eventSource": "ec2.amazonaws.com",
+    "eventType": "AwsApiCall",
+    "eventName": "StartInstances",
+    "awsRegion": "us-east-2",
+    "sourceIPAddress": "205.251.233.176",
+    "userAgent": "ec2-api-tools 1.6.12.2",
+    "requestParameters": {"instancesSet": {"items": [{"instanceId": "i-ebeaf9e2"}]}},
+    "responseElements": {"instancesSet": {"items": [{
+	"instanceId": "i-ebeaf9e2",
+	"currentState": {
+	    "code": 0,
+	    "name": "pending"
+	},
+	"previousState": {
+	    "code": 80,
+	    "name": "stopped"
+	}
+    }]}}
+}]}
+