ueventd: allow using external firmware handlers

Userspace may want to load a different firmware than the one that the
kernel requests in some cases, therefore this change adds the ability
to ueventd to run an external handler that will determine the name of
the file that should actually be loaded.

Bug: 138352500
Test: unit tests
Change-Id: Ic5da37268fd78109f83ae52d1b903bf7322a5ee5

1 files changed, 125 insertions, 0 deletions

diff --git a/init/firmware_handler_test.cpp b/init/firmware_handler_test.cpp
new file mode 100644
index 000000000..7bb603c5d
--- /dev/null
+++ b/init/firmware_handler_test.cpp
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "firmware_handler.h"
+
+#include <stdlib.h>
+#include <iostream>
+
+#include <android-base/file.h>
+#include <gtest/gtest.h>
+
+#include "uevent.h"
+
+using android::base::GetExecutablePath;
+using namespace std::literals;
+
+namespace android {
+namespace init {
+
+void FirmwareTestWithExternalHandler(const std::string& test_name, bool expect_new_firmware) {
+    auto test_path = GetExecutablePath() + " firmware " + test_name;
+    auto external_firmware_handler = ExternalFirmwareHandler(
+            "/devices/led/firmware/test_firmware001.bin", getuid(), test_path);
+
+    auto firmware_handler = FirmwareHandler({"/test"}, {external_firmware_handler});
+
+    auto uevent = Uevent{
+            .path = "/devices/led/firmware/test_firmware001.bin",
+            .firmware = "test_firmware001.bin",
+    };
+
+    if (expect_new_firmware) {
+        EXPECT_EQ("other_firmware001.bin", firmware_handler.GetFirmwarePath(uevent));
+    } else {
+        EXPECT_EQ("test_firmware001.bin", firmware_handler.GetFirmwarePath(uevent));
+    }
+
+    // Always test the base case that the handler isn't invoked if the devpath doesn't match.
+    auto uevent_different_path = Uevent{
+            .path = "/devices/led/not/mine",
+            .firmware = "test_firmware001.bin",
+    };
+    EXPECT_EQ("test_firmware001.bin", firmware_handler.GetFirmwarePath(uevent_different_path));
+}
+
+TEST(firmware_handler, HandleChange) {
+    FirmwareTestWithExternalHandler("HandleChange", true);
+}
+
+int HandleChange(int argc, char** argv) {
+    // Assert that the environment is set up correctly.
+    if (getenv("DEVPATH") != "/devices/led/firmware/test_firmware001.bin"s) {
+        std::cerr << "$DEVPATH not set correctly" << std::endl;
+        return EXIT_FAILURE;
+    }
+    if (getenv("FIRMWARE") != "test_firmware001.bin"s) {
+        std::cerr << "$FIRMWARE not set correctly" << std::endl;
+        return EXIT_FAILURE;
+    }
+    std::cout << "other_firmware001.bin" << std::endl;
+    return 0;
+}
+
+TEST(firmware_handler, HandleAbort) {
+    FirmwareTestWithExternalHandler("HandleAbort", false);
+}
+
+int HandleAbort(int argc, char** argv) {
+    abort();
+    return 0;
+}
+
+TEST(firmware_handler, HandleFailure) {
+    FirmwareTestWithExternalHandler("HandleFailure", false);
+}
+
+int HandleFailure(int argc, char** argv) {
+    std::cerr << "Failed" << std::endl;
+    return EXIT_FAILURE;
+}
+
+TEST(firmware_handler, HandleBadPath) {
+    FirmwareTestWithExternalHandler("HandleBadPath", false);
+}
+
+int HandleBadPath(int argc, char** argv) {
+    std::cout << "../firmware.bin";
+    return 0;
+}
+
+}  // namespace init
+}  // namespace android
+
+// init_test.cpp contains the main entry point for all init tests.
+int FirmwareTestChildMain(int argc, char** argv) {
+    if (argc < 3) {
+        return 1;
+    }
+
+#define RunTest(testname)                           \
+    if (argv[2] == std::string(#testname)) {        \
+        return android::init::testname(argc, argv); \
+    }
+
+    RunTest(HandleChange);
+    RunTest(HandleAbort);
+    RunTest(HandleFailure);
+    RunTest(HandleBadPath);
+
+#undef RunTest
+    return 1;
+}