wrapper: add chmods/umasks to double-build bits

counterpart of I8a92edb8ca7641e443564d20ac32fd78963d3254

BUG=chromium:914081
TEST=go test

Change-Id: I29e22ebd0767d16c1d66bdf41857bf7c79ea11b0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1792233
Tested-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Tobias Bosch <tbosch@google.com>

2 files changed, 71 insertions, 0 deletions

diff --git a/compiler_wrapper/disable_werror_flag.go b/compiler_wrapper/disable_werror_flag.go
index a5d22f52..b639eb37 100644
--- a/compiler_wrapper/disable_werror_flag.go
+++ b/compiler_wrapper/disable_werror_flag.go
@@ -10,6 +10,7 @@ import (
 	"io/ioutil"
 	"os"
 	"strings"
+	"syscall"
 )
 
 func shouldForceDisableWError(env env) bool {
@@ -65,6 +66,11 @@ func doubleBuildWithWNoError(env env, cfg *config, originalCmd *command) (exitCo
 	// reasonable for that to fail the build. This is all meant for FYI-like
 	// builders in the first place.
 
+	// Buildbots use a nonzero umask, which isn't quite what we want: these directories should
+	// be world-readable and world-writable.
+	oldMask := syscall.Umask(0)
+	defer syscall.Umask(oldMask)
+
 	// Allow root and regular users to write to this without issue.
 	if err := os.MkdirAll(cfg.newWarningsDir, 0777); err != nil {
 		return 0, wrapErrorwithSourceLocf(err, "error creating warnings directory %s", cfg.newWarningsDir)
@@ -83,6 +89,10 @@ func doubleBuildWithWNoError(env env, cfg *config, originalCmd *command) (exitCo
 		return 0, wrapErrorwithSourceLocf(err, "error creating warnings file")
 	}
 
+	if err := tmpFile.Chmod(0666); err != nil {
+		return 0, wrapErrorwithSourceLocf(err, "error chmoding the file to be world-readable/writeable")
+	}
+
 	lines := []string{}
 	if originalStderrBuffer.Len() > 0 {
 		lines = append(lines, originalStderrBuffer.String())
diff --git a/compiler_wrapper/disable_werror_flag_test.go b/compiler_wrapper/disable_werror_flag_test.go
index 40d0f8c7..fb25d193 100644
--- a/compiler_wrapper/disable_werror_flag_test.go
+++ b/compiler_wrapper/disable_werror_flag_test.go
@@ -311,3 +311,64 @@ func readLoggedWarnings(ctx *testContext) *warningsJSONData {
 	}
 	return &jsonData
 }
+
+func TestDoubleBuildWerrorChmodsThingsAppropriately(t *testing.T) {
+	withForceDisableWErrorTestContext(t, func(ctx *testContext) {
+		ctx.cmdMock = func(cmd *command, stdin io.Reader, stdout io.Writer, stderr io.Writer) error {
+			switch ctx.cmdCount {
+			case 1:
+				if err := verifyArgCount(cmd, 0, "-Wno-error"); err != nil {
+					return err
+				}
+				fmt.Fprint(stderr, "-Werror originalerror")
+				return newExitCodeError(1)
+			case 2:
+				if err := verifyArgCount(cmd, 1, "-Wno-error"); err != nil {
+					return err
+				}
+				return nil
+			default:
+				t.Fatalf("unexpected command: %#v", cmd)
+				return nil
+			}
+		}
+		ctx.must(callCompiler(ctx, ctx.cfg, ctx.newCommand(clangX86_64, mainCc)))
+		if ctx.cmdCount != 2 {
+			// Later errors are likely senseless if we didn't get called twice.
+			t.Fatalf("expected 2 calls. Got: %d", ctx.cmdCount)
+		}
+
+		t.Logf("Warnings dir is at %q", ctx.cfg.newWarningsDir)
+		warningsDir, err := os.Open(ctx.cfg.newWarningsDir)
+		if err != nil {
+			t.Fatalf("failed to open the new warnings dir: %v", err)
+		}
+		defer warningsDir.Close()
+
+		fi, err := warningsDir.Stat()
+		if err != nil {
+			t.Fatalf("failed stat'ing the warnings dir: %v", err)
+		}
+
+		permBits := func(mode os.FileMode) int { return int(mode & 0777) }
+
+		if perms := permBits(fi.Mode()); perms != 0777 {
+			t.Errorf("mode for tempdir are %#o; expected 0777", perms)
+		}
+
+		entries, err := warningsDir.Readdir(0)
+		if err != nil {
+			t.Fatalf("failed reading entries of the tempdir: %v", err)
+		}
+
+		if len(entries) != 1 {
+			t.Errorf("found %d tempfiles in the tempdir; expected 1", len(entries))
+		}
+
+		for _, e := range entries {
+			if perms := permBits(e.Mode()); perms != 0666 {
+				t.Errorf("mode for %q is %#o; expected 0666", e.Name(), perms)
+			}
+		}
+	})
+}