servicemanager: use libbinder

Bug: 135768100
Test: boot
Test: servicemanager_test

Change-Id: I9d657b6c0d0be0f763b6d54e0e6c6bc1c1e3fc7a
(cherry picked from commit 3e092daa14c63831d76d3ad6e56b2919a0523536)
diff --git a/cmds/servicemanager/ServiceManager.cpp b/cmds/servicemanager/ServiceManager.cpp
new file mode 100644
index 0000000..b88b67d
--- /dev/null
+++ b/cmds/servicemanager/ServiceManager.cpp
@@ -0,0 +1,144 @@
+/*
+ * 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 "ServiceManager.h"
+
+#include <android-base/logging.h>
+#include <cutils/android_filesystem_config.h>
+#include <cutils/multiuser.h>
+
+using ::android::binder::Status;
+
+namespace android {
+
+ServiceManager::ServiceManager(std::unique_ptr<Access>&& access) : mAccess(std::move(access)) {}
+
+Status ServiceManager::getService(const std::string& name, sp<IBinder>* outBinder) {
+    // Servicemanager is single-threaded and cannot block. This method exists for legacy reasons.
+    return checkService(name, outBinder);
+}
+
+Status ServiceManager::checkService(const std::string& name, sp<IBinder>* outBinder) {
+    auto ctx = mAccess->getCallingContext(name);
+
+    auto it = mNameToService.find(name);
+    if (it == mNameToService.end()) {
+        *outBinder = nullptr;
+        return Status::ok();
+    }
+
+    const Service& service = it->second;
+
+    if (!service.allowIsolated) {
+        uid_t appid = multiuser_get_app_id(ctx.uid);
+        bool isIsolated = appid >= AID_ISOLATED_START && appid <= AID_ISOLATED_END;
+
+        if (isIsolated) {
+            *outBinder = nullptr;
+            return Status::ok();
+        }
+    }
+
+    // TODO(b/136023468): move this check to be first
+    if (!mAccess->canFind(ctx)) {
+        // returns ok and null for legacy reasons
+        *outBinder = nullptr;
+        return Status::ok();
+    }
+
+    *outBinder = service.binder;
+    return Status::ok();
+}
+
+Status ServiceManager::addService(const std::string& name, const sp<IBinder>& binder, bool allowIsolated, int32_t dumpPriority) {
+    auto ctx = mAccess->getCallingContext(name);
+
+    // apps cannot add services
+    if (multiuser_get_app_id(ctx.uid) >= AID_APP) {
+        return Status::fromExceptionCode(Status::EX_SECURITY);
+    }
+
+    if (!mAccess->canAdd(ctx)) {
+        return Status::fromExceptionCode(Status::EX_SECURITY);
+    }
+
+    if (binder == nullptr) {
+        return Status::fromExceptionCode(Status::EX_ILLEGAL_ARGUMENT);
+    }
+
+    // match legacy rules
+    if (name.size() == 0 || name.size() > 127) {
+        return Status::fromExceptionCode(Status::EX_ILLEGAL_ARGUMENT);
+    }
+
+    if (OK != binder->linkToDeath(this)) {
+        LOG(ERROR) << "Could not linkToDeath when adding " << name;
+        return Status::fromExceptionCode(Status::EX_ILLEGAL_STATE);
+    }
+
+    auto it = mNameToService.find(name);
+    if (it != mNameToService.end()) {
+        if (OK != it->second.binder->unlinkToDeath(this)) {
+            LOG(WARNING) << "Could not unlinkToDeath when adding " << name;
+        }
+    }
+
+    mNameToService[name] = Service {
+        .binder = binder,
+        .allowIsolated = allowIsolated,
+        .dumpPriority = dumpPriority,
+    };
+
+    return Status::ok();
+}
+
+Status ServiceManager::listServices(int32_t dumpPriority, std::vector<std::string>* outList) {
+    if (!mAccess->canList(mAccess->getCallingContext(""))) {
+        return Status::fromExceptionCode(Status::EX_SECURITY);
+    }
+
+    size_t toReserve = 0;
+    for (auto const& [name, service] : mNameToService) {
+        (void) name;
+
+        if (service.dumpPriority & dumpPriority) ++toReserve;
+    }
+
+    CHECK(outList->empty());
+
+    outList->reserve(toReserve);
+    for (auto const& [name, service] : mNameToService) {
+        (void) service;
+
+        if (service.dumpPriority & dumpPriority) {
+            outList->push_back(name);
+        }
+    }
+
+    return Status::ok();
+}
+
+void ServiceManager::binderDied(const wp<IBinder>& who) {
+    for (auto it = mNameToService.begin(); it != mNameToService.end();) {
+        if (who == it->second.binder) {
+            it = mNameToService.erase(it);
+        } else {
+            ++it;
+        }
+    }
+}
+
+}  // namespace android