聊一聊鸿蒙系统中的samgr组件

风在云颠

发布于 2021-9-24 16:48

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简介

samgr组件是OpenHarmony的核心组件，提供OpenHarmony系统服务启动、注册、查询等功能。

聊一聊鸿蒙系统中的samgr组件-鸿蒙开发者社区

/foundation/distributedschedule/services/samgr/
├── native
│   ├── BUILD.gn  # 部件编译脚本
│   ├── include   # 头文件存放目录
│   ├── samgr.rc  # samgr启动配置文件
│   ├── source    # 源代码存放目录
│   ├── test      # 测试代码存放目录

说明

samgr服务接收到sa框架层发送的注册消息，会在本地缓存中存入系统服务相关信息。

int32_t SystemAbilityManager::AddSystemAbility(int32_t systemAbilityId, const sptr<IRemoteObject>& ability,
    const SAExtraProp& extraProp)
{
    if (!CheckInputSysAbilityId(systemAbilityId) || ability == nullptr || (!CheckCapability(extraProp.capability))) {
        HILOGE("AddSystemAbilityExtra input params is invalid.");
        return ERR_INVALID_VALUE;
    }
    {
        unique_lock<shared_mutex> writeLock(abilityMapLock_);
        auto saSize = abilityMap_.size();
        if (saSize >= MAX_SERVICES) {
            HILOGE("map size error, (Has been greater than %zu)", saSize);
            return ERR_INVALID_VALUE;
        }
        SAInfo saInfo;
        saInfo.remoteObj = ability;
        saInfo.isDistributed = extraProp.isDistributed;
        saInfo.capability = extraProp.capability;
        saInfo.permission = Str16ToStr8(extraProp.permission);
        abilityMap_[systemAbilityId] = std::move(saInfo);
        HILOGI("insert %{public}d. size : %zu,", systemAbilityId, abilityMap_.size());
    }
    if (abilityDeath_ != nullptr) {
        ability->AddDeathRecipient(abilityDeath_);
    }
    FindSystemAbilityManagerNotify(systemAbilityId, ADD_SYSTEM_ABILITY_TRANSACTION);
    u16string strName = Str8ToStr16(to_string(systemAbilityId));
    if (extraProp.isDistributed && dBinderService_ != nullptr) {
        dBinderService_->RegisterRemoteProxy(strName, ability);
        HILOGD("AddSystemAbility RegisterRemoteProxy, serviceId is %{public}d", systemAbilityId);
    }
    if (systemAbilityDataStorage_ == nullptr) {
        HILOGE("AddSystemAbility systemAbilityDataStorage not init!");
        return ERR_NO_INIT;
    }
    if (extraProp.isDistributed) {
        systemAbilityDataStorage_->ClearSyncRecords();
        DoInsertSaData(strName, ability, extraProp);
    }
}

对于本地服务而言，samgr服务接收到sa框架层发送的获取消息，会通过服务id，查找到对应服务的代理对象，然后返回给sa框架。

sptr<IRemoteObject> SystemAbilityManager::CheckSystemAbility(int32_t systemAbilityId)
{
    if (!CheckInputSysAbilityId(systemAbilityId)) {
        return nullptr;
    }

    std::string selectedDeviceId;
    if (CheckRemoteSa(to_string(systemAbilityId), selectedDeviceId)) {
       return CheckSystemAbility(systemAbilityId, selectedDeviceId);
    }

    shared_lock<shared_mutex> readLock(abilityMapLock_);
    auto iter = abilityMap_.find(systemAbilityId);
    if (iter != abilityMap_.end()) {
        auto callingUid = IPCSkeleton::GetCallingUid();
        if (IsSystemApp(callingUid) || CheckPermission(iter->second.permission)) {
             return iter->second.remoteObj;
        }
        return nullptr;
    }
    return nullptr;
}