compiler_wrapper: report parent processes' info in warnings tarballs

The bug I'm chasing down right now depends on environment variables, and
could be due to a `make` invocation in one of N places. Having this
context available to me is useful.

It seriously pollutes the JSON we dump, but use of `jq` that I've put in
the doc about this makes that a non-issue.

BUG=None
TEST=Ran on stress-ng. parent process info was dumped.

Change-Id: Ib4d3b6c9887b4cf2a38472ef299c81af27e9a617
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2481829
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>

1 files changed, 65 insertions, 0 deletions

diff --git a/compiler_wrapper/disable_werror_flag_test.go b/compiler_wrapper/disable_werror_flag_test.go
index ecc1090b..0c43dbe0 100644
--- a/compiler_wrapper/disable_werror_flag_test.go
+++ b/compiler_wrapper/disable_werror_flag_test.go
@@ -500,3 +500,68 @@ func TestClangTidyDoubleBuildClangError(t *testing.T) {
 		}
 	})
 }
+
+func TestProcPidStatParsingWorksAsIntended(t *testing.T) {
+	t.Parallel()
+
+	type expected struct {
+		parent int
+		ok     bool
+	}
+
+	testCases := []struct {
+		input    string
+		expected expected
+	}{
+		{
+			input: "2556041 (cat) R 2519408 2556041 2519408 34818 2556041 4194304",
+			expected: expected{
+				parent: 2519408,
+				ok:     true,
+			},
+		},
+		{
+			input: "2556041 (c a t) R 2519408 2556041 2519408 34818 2556041 4194304",
+			expected: expected{
+				parent: 2519408,
+				ok:     true,
+			},
+		},
+		{
+			input: "",
+			expected: expected{
+				ok: false,
+			},
+		},
+		{
+			input: "foo (bar)",
+			expected: expected{
+				ok: false,
+			},
+		},
+		{
+			input: "foo (bar) baz",
+			expected: expected{
+				ok: false,
+			},
+		},
+		{
+			input: "foo (bar) baz 1qux2",
+			expected: expected{
+				ok: false,
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		parent, ok := parseParentPidFromPidStat(tc.input)
+		if tc.expected.ok != ok {
+			t.Errorf("Got ok=%v when parsing %q; expected %v", ok, tc.input, tc.expected.ok)
+			continue
+		}
+
+		if tc.expected.parent != parent {
+			t.Errorf("Got parent=%v when parsing %q; expected %v", parent, tc.input, tc.expected.parent)
+		}
+	}
+}