Clean environment variables to account for sandbox work directory.

Unset HOME to prevent username leak.

Bug: 363037195

Change-Id: I7a8694f746d58de8f6e41adb6ad52abbaf955ef4
diff --git a/ui/build/config.go b/ui/build/config.go
index dfe0dfe..90b98f5 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -214,6 +214,10 @@
 		sandboxConfig:         &SandboxConfig{},
 		ninjaWeightListSource: DEFAULT,
 	}
+	wd, err := os.Getwd()
+	if err != nil {
+		ctx.Fatalln("Failed to get working directory:", err)
+	}
 
 	// Skip soong tests by default on Linux
 	if runtime.GOOS == "linux" {
@@ -245,17 +249,13 @@
 
 	// Make sure OUT_DIR is set appropriately
 	if outDir, ok := ret.environ.Get("OUT_DIR"); ok {
-		ret.environ.Set("OUT_DIR", filepath.Clean(outDir))
+		ret.environ.Set("OUT_DIR", ret.sandboxPath(wd, filepath.Clean(outDir)))
 	} else {
 		outDir := "out"
 		if baseDir, ok := ret.environ.Get("OUT_DIR_COMMON_BASE"); ok {
-			if wd, err := os.Getwd(); err != nil {
-				ctx.Fatalln("Failed to get working directory:", err)
-			} else {
-				outDir = filepath.Join(baseDir, filepath.Base(wd))
-			}
+			outDir = filepath.Join(baseDir, filepath.Base(wd))
 		}
-		ret.environ.Set("OUT_DIR", outDir)
+		ret.environ.Set("OUT_DIR", ret.sandboxPath(wd, outDir))
 	}
 
 	// loadEnvConfig needs to know what the OUT_DIR is, so it should
@@ -350,6 +350,9 @@
 
 		// Use config.useN2 instead.
 		"SOONG_USE_N2",
+
+		// Leaks usernames into environment.
+		"HOME",
 	)
 
 	if ret.UseGoma() || ret.ForceUseGoma() {
@@ -361,12 +364,12 @@
 	ret.environ.Set("PYTHONDONTWRITEBYTECODE", "1")
 
 	tmpDir := absPath(ctx, ret.TempDir())
-	ret.environ.Set("TMPDIR", tmpDir)
+	ret.environ.Set("TMPDIR", ret.sandboxPath(wd, tmpDir))
 
 	// Always set ASAN_SYMBOLIZER_PATH so that ASAN-based tools can symbolize any crashes
 	symbolizerPath := filepath.Join("prebuilts/clang/host", ret.HostPrebuiltTag(),
 		"llvm-binutils-stable/llvm-symbolizer")
-	ret.environ.Set("ASAN_SYMBOLIZER_PATH", absPath(ctx, symbolizerPath))
+	ret.environ.Set("ASAN_SYMBOLIZER_PATH", ret.sandboxPath(wd, absPath(ctx, symbolizerPath)))
 
 	// Precondition: the current directory is the top of the source tree
 	checkTopDir(ctx)
@@ -420,15 +423,18 @@
 
 	ret.configureLocale(ctx)
 
-	newPath := []string{filepath.Join(absJavaHome, "bin")}
+	newPath := []string{ret.sandboxPath(wd, filepath.Join(absJavaHome, "bin"))}
 	if path, ok := ret.environ.Get("PATH"); ok && path != "" {
-		newPath = append(newPath, path)
+		entries := strings.Split(path, string(filepath.ListSeparator))
+		for _, ent := range entries {
+			newPath = append(newPath, ret.sandboxPath(wd, ent))
+		}
 	}
 
 	ret.environ.Unset("OVERRIDE_ANDROID_JAVA_HOME")
-	ret.environ.Set("JAVA_HOME", absJavaHome)
-	ret.environ.Set("ANDROID_JAVA_HOME", javaHome)
-	ret.environ.Set("ANDROID_JAVA8_HOME", java8Home)
+	ret.environ.Set("JAVA_HOME", ret.sandboxPath(wd, absJavaHome))
+	ret.environ.Set("ANDROID_JAVA_HOME", ret.sandboxPath(wd, javaHome))
+	ret.environ.Set("ANDROID_JAVA8_HOME", ret.sandboxPath(wd, java8Home))
 	ret.environ.Set("PATH", strings.Join(newPath, string(filepath.ListSeparator)))
 
 	// b/286885495, https://bugzilla.redhat.com/show_bug.cgi?id=2227130: some versions of Fedora include patches
@@ -444,7 +450,7 @@
 		ret.buildDateTime = strconv.FormatInt(time.Now().Unix(), 10)
 	}
 
-	ret.environ.Set("BUILD_DATETIME_FILE", buildDateTimeFile)
+	ret.environ.Set("BUILD_DATETIME_FILE", ret.sandboxPath(wd, buildDateTimeFile))
 
 	if _, ok := ret.environ.Get("BUILD_USERNAME"); !ok {
 		username := "unknown"
@@ -455,6 +461,7 @@
 		}
 		ret.environ.Set("BUILD_USERNAME", username)
 	}
+	ret.environ.Set("PWD", ret.sandboxPath(wd, wd))
 
 	if ret.UseRBE() {
 		for k, v := range getRBEVars(ctx, Config{ret}) {
@@ -1296,6 +1303,19 @@
 	return err == nil
 }
 
+func (c *configImpl) sandboxPath(base, in string) string {
+	if !c.UseABFS() {
+		return in
+	}
+
+	rel, err := filepath.Rel(base, in)
+	if err != nil {
+		return in
+	}
+
+	return filepath.Join(abfsSrcDir, rel)
+}
+
 func (c *configImpl) UseRBE() bool {
 	// These alternate modes of running Soong do not use RBE / reclient.
 	if c.Queryview() || c.JsonModuleGraph() {
@@ -1716,6 +1736,11 @@
 }
 
 func (c *configImpl) SkipMetricsUpload() bool {
+	// b/362625275 - Metrics upload sometimes prevents abfs unmount
+	if c.UseABFS() {
+		return true
+	}
+
 	return c.skipMetricsUpload
 }