Add utility to wait for strongbox keymaster to be ready

It's important that vold not be started until both keymaster HALs are
running, or strongbox won't work.  This utility waits until both are
ready, then returns.

Bug: 90406546
Test: Manual
Change-Id: Ida0aa0e5f41b5fe65c814cc2d3cd37c565b0a4a1

2 files changed, 86 insertions, 0 deletions

diff --git a/keymaster/Android.bp b/keymaster/Android.bp
new file mode 100644
index 00000000..02d52a96
--- /dev/null
+++ b/keymaster/Android.bp
@@ -0,0 +1,27 @@
+//
+// Copyright (C) 2018 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.
+
+cc_binary {
+    name: "wait_for_strongbox",
+    relative_install_path: "hw",
+    srcs: [ "wait_for_strongbox.cpp" ],
+    cflags: [ "-Werror", "-Wall" ],
+    shared_libs: [
+        "android.hardware.keymaster@4.0",
+        "libbase",
+        "libkeymaster4support",
+    ],
+    proprietary: true,
+}
diff --git a/keymaster/wait_for_strongbox.cpp b/keymaster/wait_for_strongbox.cpp
new file mode 100644
index 00000000..7516774f
--- /dev/null
+++ b/keymaster/wait_for_strongbox.cpp
@@ -0,0 +1,59 @@
+/*
+ ** Copyright 2018, 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 <unistd.h>
+
+#define LOG_TAG "wait_for_strongbox"
+#include <android-base/logging.h>
+
+#include <keymasterV4_0/Keymaster.h>
+
+using android::hardware::keymaster::V4_0::SecurityLevel;
+using android::hardware::keymaster::V4_0::support::Keymaster;
+
+useconds_t kWaitTimeMicroseconds = 10 * 1000;  // 10 milliseconds
+
+int main() {
+    for (unsigned cycleCount = 0; /* Forever */; ++cycleCount) {
+        auto keymasters = Keymaster::enumerateAvailableDevices();
+
+        bool foundStrongBox = false;
+        bool foundTee = false;
+        for (auto &dev : keymasters) {
+            SecurityLevel securityLevel = dev->halVersion().securityLevel;
+            uint8_t majorVersion = dev->halVersion().majorVersion;
+            if (securityLevel == SecurityLevel::STRONGBOX && majorVersion == 4) {
+                foundStrongBox = true;
+            }
+            if (securityLevel == SecurityLevel::TRUSTED_ENVIRONMENT && majorVersion == 4) {
+                foundTee = true;
+            }
+        }
+
+        if (foundTee && foundStrongBox) {
+            return 0;
+        }
+        if (cycleCount % 10 == 1) {
+            if (!foundStrongBox) {
+                LOG(WARNING) << "Still waiting for StrongBox Keymaster";
+            }
+            if (!foundTee) {
+                LOG(WARNING) << "Still waiting for TEE Keymaster";
+            }
+        }
+        usleep(kWaitTimeMicroseconds);
+    }
+}