Merge "Add derive_sdk binary for reading sdk protos"

apex/sdkext/Android.bp

@@ -15,7 +15,9 @@
 apex {
     name: "com.android.sdkext",
     manifest: "manifest.json",
+    binaries: [ "derive_sdk" ],
     java_libs: [ "framework-sdkext" ],
+    prebuilts: [ "com.android.sdkext.ldconfig" ],
     key: "com.android.sdkext.key",
     certificate: ":com.android.sdkext.certificate",
 }
@@ -30,3 +32,10 @@ android_app_certificate {
     name: "com.android.sdkext.certificate",
     certificate: "com.android.sdkext",
 }
+
+prebuilt_etc {
+    name: "com.android.sdkext.ldconfig",
+    src: "ld.config.txt",
+    filename: "ld.config.txt",
+    installable: false,
+}

apex/sdkext/derive_sdk/Android.bp

@@ -0,0 +1,31 @@
+// 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.
+
+cc_binary {
+    name: "derive_sdk",
+    srcs: [
+        "derive_sdk.cpp",
+        "sdk.proto",
+    ],
+    proto: {
+        type: "lite",
+    },
+    sdk_version: "current",
+    stl: "c++_static",
+    shared_libs: [ "liblog" ],
+    static_libs: [
+        "libbase_ndk",
+        "libprotobuf-cpp-lite-ndk",
+    ],
+}

apex/sdkext/derive_sdk/derive_sdk.cpp

@@ -0,0 +1,77 @@
+/*
+ * 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.
+ */
+
+#define LOG_TAG "derive_sdk"
+
+#include <algorithm>
+#include <dirent.h>
+#include <iostream>
+#include <sys/stat.h>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+
+#include "frameworks/base/apex/sdkext/derive_sdk/sdk.pb.h"
+
+using com::android::sdkext::proto::SdkVersion;
+
+int main(int, char**) {
+    std::unique_ptr<DIR, decltype(&closedir)> apex(opendir("/apex"), closedir);
+    if (!apex) {
+        LOG(ERROR) << "Could not read /apex";
+        return EXIT_FAILURE;
+    }
+    struct dirent* de;
+    std::vector<std::string> paths;
+    while ((de = readdir(apex.get()))) {
+        std::string name = de->d_name;
+        if (name[0] == '.' || name.find('@') != std::string::npos) {
+            // Skip <name>@<ver> dirs, as they are bind-mounted to <name>
+            continue;
+        }
+        std::string path = "/apex/" + name + "/etc/sdkinfo.binarypb";
+        struct stat statbuf;
+        if (stat(path.c_str(), &statbuf) == 0) {
+            paths.push_back(path);
+        }
+    }
+
+    std::vector<int> versions;
+    for (const auto& path : paths) {
+        std::string contents;
+        if (!android::base::ReadFileToString(path, &contents, true)) {
+            LOG(ERROR) << "failed to read " << path;
+            continue;
+        }
+        SdkVersion sdk_version;
+        if (!sdk_version.ParseFromString(contents)) {
+            LOG(ERROR) << "failed to parse " << path;
+            continue;
+        }
+        versions.push_back(sdk_version.version());
+    }
+    auto itr = std::min_element(versions.begin(), versions.end());
+    std::string prop_value = itr == versions.end() ? "0" : std::to_string(*itr);
+
+    if (!android::base::SetProperty("persist.com.android.sdkext.sdk_info", prop_value)) {
+        LOG(ERROR) << "failed to set sdk_info prop";
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}

apex/sdkext/derive_sdk/sdk.proto

@@ -0,0 +1,25 @@
+/*
+ * 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.
+ */
+
+syntax = "proto3";
+package com.android.sdkext.proto;
+
+option java_outer_classname = "SdkProto";
+option optimize_for = LITE_RUNTIME;
+
+message SdkVersion {
+  int32 version = 1;
+}

apex/sdkext/ld.config.txt

@@ -0,0 +1,31 @@
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Bionic loader config file for the sdkext apex.
+
+dir.sdkext = /apex/com.android.sdkext/bin/
+
+[sdkext]
+additional.namespaces = platform
+
+namespace.default.isolated = true
+namespace.default.links = platform
+namespace.default.link.platform.allow_all_shared_libs = true
+
+###############################################################################
+# "platform" namespace: used for NDK libraries
+###############################################################################
+namespace.platform.isolated = true
+namespace.platform.search.paths = /system/${LIB}
+namespace.platform.asan.search.paths = /data/asan/system/${LIB}
+
+# /system/lib/libc.so, etc are symlinks to /apex/com.android.lib/lib/bionic/libc.so, etc.
+# Add /apex/... path to the permitted paths because linker uses realpath(3)
+# to check the accessibility of the lib. We could add this to search.paths
+# instead but that makes the resolution of bionic libs be dependent on
+# the order of /system/lib and /apex/... in search.paths. If /apex/...
+# is after /system/lib, then /apex/... is never tried because libc.so
+# is always found in /system/lib but fails to pass the accessibility test
+# because of its realpath.  It's better to not depend on the ordering if
+# possible.
+namespace.platform.permitted.paths = /apex/com.android.runtime/${LIB}/bionic
+namespace.platform.asan.permitted.paths = /apex/com.android.runtime/${LIB}/bionic