{% import 'docs/_common/_doc_widgets.md' as widgets %}
软件隔离模型
<<../../_common/intro/_sandboxing_intro.md>>
<<../../_common/intro/_sandboxing_sandboxing.md>>
<<../../_common/intro/_sandboxing_namespaces.md>>
练习：命名空间
在本练习中，您将使用命令行来更详细地探索组件的命名空间（namespace）的内容。
<<../_common/_start_femu.md>>
在 hub 中找到一个组件
Fuchsia 提供了 Hub 作为诊断接口， 用于获取系统中运行的组件实例的信息。 您可以使用 hub 的目录结构来探索组件及其命名空间。
连接到设备命令行并输入以下 ls 命令
来列出 /hub-v2/children/core/children 下的 core 领域（realm）的组件:
```none {:.devsite-disable-click-to-copy} activity appmgr brightness_manager bt-avrcp build-info ...
<!--
This is a list of many of the core Fuchsia system components. To see
more details about a specific component, list its directory contents.
-->
这是许多核心 Fuchsia 系统组件的一个列表。要查看更多关于特定组件的详细信息，可以列出它的目录内容。
<!--
Try this for the `http-client` component:
-->
对 `http-client` 组件试试这个:
```posix-terminal
fx shell ls /hub-v2/children/core/children/network/children/http-client
```none {:.devsite-disable-click-to-copy} children component_type debug deleting exec id resolved url
<!-- ### Explore the namespace and outgoing directory -->
### 探索命名空间和出口目录
<!--
You'll find a running component's **namespace** under the `exec/in` path inside
the hub.
-->
您将在 hub 内部的 `exec/in` 路径下找到运行中组件的**命名空间**。
```posix-terminal
fx shell ls /hub-v2/children/core/children/network/children/http-client/exec/in
```none {:.devsite-disable-click-to-copy} config pkg svc
<!-- Here are some quick highlights of each element: -->
对每个元素简单说明如下:
<!--
* `config/`: configuration data for the component
* `pkg/`: the contents of the component's package
* `svc/`: system services available to the component
-->
* `config/`: 组件的配置数据
* `pkg/`: 组件的包的内容
* `svc/`: 可供组件使用的系统服务
<!--
List the contents of the incoming `svc/` directory. This
directory contains
[service nodes](https://fuchsia.dev/reference/fidl/fuchsia.io#NodeInfo)
representing the system services provided to this component.
-->
列出 `svc/` 目录的内容。这个目录包含
[服务节点](https://fuchsia.dev/reference/fidl/fuchsia.io#NodeInfo)，
表示提供给这个组件的系统服务。
```posix-terminal
fx shell ls /hub-v2/children/core/children/network/children/http-client/exec/in/svc
```none {:.devsite-disable-click-to-copy} fuchsia.logger.LogSink fuchsia.net.name.Lookup fuchsia.posix.socket.Provider
<!--
Each of these services is accessible over a well-known protocol defined by a
[Fuchsia Interface Definition Language (FIDL)][glossary.FIDL] interface.
Components provide system services through their **outgoing directory**, which
is mapped to the `exec/out` path inside the hub.
-->
每个服务都通过一个公有协议访问，其由一个
[Fuchsia 接口定义语言（Fuchsia Interface Definition Language，FIDL)][glossary.FIDL]接口定义。
组件通过其**出口目录**（outgoing directory）来提供系统服务，
这个目录被映射到 hub 内部的 `exec/out` 路径。
<!--
List the contents of the outgoing `svc/` directory to see the system services
this component provides.
-->
列出 `svc/` 出口目录来查看这个组件提供的系统服务。
```posix-terminal
fx shell ls /hub-v2/children/core/children/network/children/http-client/exec/out/svc
none {:.devsite-disable-click-to-copy}
fuchsia.net.http.Loader
我们将在以后更详细地探索 FIDL 协议及如何访问各种服务。