platform_system_vold/VoldNativeService.cpp
Jeff Sharkey 068c6be622 Start paving the way for vold calls over Binder.
This change is the bare minimum needed to publish a new vold
Binder service and move the simple "reset" call over to go through
the new interface.

Test: builds, boots
Bug: 13758960
Change-Id: I5b70976653c69f92e1efc8d1f432b2038eb618a4
2017-09-06 14:06:06 -06:00

116 lines
3.3 KiB
C++

/*
* Copyright (C) 2017 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 "VoldNativeService.h"
#include "VolumeManager.h"
#include <fstream>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <private/android_filesystem_config.h>
#ifndef LOG_TAG
#define LOG_TAG "vold"
#endif
using android::base::StringPrintf;
using std::endl;
namespace android {
namespace vold {
namespace {
constexpr const char* kDump = "android.permission.DUMP";
static binder::Status ok() {
return binder::Status::ok();
}
static binder::Status exception(uint32_t code, const std::string& msg) {
return binder::Status::fromExceptionCode(code, String8(msg.c_str()));
}
binder::Status checkPermission(const char* permission) {
pid_t pid;
uid_t uid;
if (checkCallingPermission(String16(permission), reinterpret_cast<int32_t*>(&pid),
reinterpret_cast<int32_t*>(&uid))) {
return ok();
} else {
return exception(binder::Status::EX_SECURITY,
StringPrintf("UID %d / PID %d lacks permission %s", uid, pid, permission));
}
}
binder::Status checkUid(uid_t expectedUid) {
uid_t uid = IPCThreadState::self()->getCallingUid();
if (uid == expectedUid || uid == AID_ROOT) {
return ok();
} else {
return exception(binder::Status::EX_SECURITY,
StringPrintf("UID %d is not expected UID %d", uid, expectedUid));
}
}
#define ENFORCE_UID(uid) { \
binder::Status status = checkUid((uid)); \
if (!status.isOk()) { \
return status; \
} \
}
} // namespace
status_t VoldNativeService::start() {
IPCThreadState::self()->disableBackgroundScheduling(true);
status_t ret = BinderService<VoldNativeService>::publish();
if (ret != android::OK) {
return ret;
}
sp<ProcessState> ps(ProcessState::self());
ps->startThreadPool();
ps->giveThreadPoolName();
return android::OK;
}
status_t VoldNativeService::dump(int fd, const Vector<String16> & /* args */) {
auto out = std::fstream(StringPrintf("/proc/self/fd/%d", fd));
const binder::Status dump_permission = checkPermission(kDump);
if (!dump_permission.isOk()) {
out << dump_permission.toString8() << endl;
return PERMISSION_DENIED;
}
out << "vold is happy!" << endl;
out.flush();
return NO_ERROR;
}
binder::Status VoldNativeService::reset() {
ENFORCE_UID(AID_SYSTEM);
LOG(INFO) << "reset() via Binder!";
VolumeManager::Instance()->reset();
return ok();
}
} // namespace vold
} // namespace android