harmony 鸿蒙Sandbox Management

2022-08-09
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Sandbox Management

Overview

Function

OpenHarmony supports two types of sandbox, namely, system sandbox and chipset sandbox.

The system sandbox and chipset sandbox are created in the init module. Native services choose to enter the system sandbox or chipset sandbox based on their functions.

Sandbox components can be isolated through the mount attribute if mount-bind-paths or mount-bind-files is set for them in configuration files such as system-sandbox.json and chipset-sandbox.json. In addition, a sandbox debugging tool is provided to facilitate sandbox debugging, verification, and optimization. For details about commands, see Description of begetctl Commands.

Constraints

The sandbox management module is available only for the standard system.

How to Develop

Parameters

Table 1 Parameters in the sandbox configuration file

JSON Prefix	Description
sandbox-root	Root directory of the sandbox.
mount-bind-paths	Directory to mount.
mount-bind-files	File to mount.
src-path	Source path of the directory or file to mount.
sandbox-path	Target path in the sandbox.
sandbox-flags	Mount flag. The default value is bind rec.
ignore	Whether to ignore a mounting failure. If the value is set to 1, the system ignores the mounting failure and proceeds with the subsequent step.
target-name	Directory to link.
link-name	Target link in the sandbox.

Available APIs

Logical storage structure of the sandbox:

// Main functions
// name is "system" or "chipset"
bool InitSandboxWithName(const char *name); // Parsing to the JSON structure

typedef struct {
    ListNode pathMountsHead;   // sandbox mount_path list head
    ListNode fileMountsHead;   // sandbox mount_file list head
    ListNode linksHead;        // sandbox symbolic link list head
    char *rootPath;            // /mnt/sandbox/system|vendor|xxx
    char name[MAX_BUFFER_LEN]; // name of sandbox. i.e system, chipset etc.
    bool isCreated;            // sandbox already created or not
    int ns;                    // namespace                                // namespace
} sandbox_t;

How to Develop

Create a sandbox.
- Create a system or chipset sandbox and configure the corresponding system-sandbox.json or chipset-sandbox.json file. For details about how to configure the JSON file, see Sandbox JSON File Configuration.
- By default, the sandbox function of a service is enabled. If you do not want to move the service to the sandbox, set sandbox to 0 in the .cfg file. Otherwsie, set sandbox to 1. "sandbox" : 1
Modify the JSON file configuration of the sandbox.
- Go to the /system/etc/sandbox/ directory, and run cat system-sandbox.json and cat chipset-sandbox.json. If you are using a 64-bit system, run cat system-sandbox64.json and cat chipset-sandbox64.json instead.
- Modify the sandbox configuration files in the base/startup/init/interfaces/innerkits/sandbox directory. After that, restart the system.

Development Example

Sandbox JSON File Configuration

{
    "sandbox-root" : "/mnt/sandbox/system",
    "mount-bind-paths" : [{
        "src-path" : "/system/lib/ndk",
        "sandbox-path" : "/system/lib/ndk",
        "sandbox-flags" : [ "bind", "rec", "private" ]
    }],
    "mount-bind-files" : [{
        "src-path" : "/system/lib/ld-musl-aarch64.so.1",
        "sandbox-path" : "/system/lib/ld-musl-aarch64.so.1",
        "sandbox-flags" : [ "bind", "rec", "private" ]
    }],
    "symbol-links" : [{
        "target-name" : "/vendor/lib",
        "link-name" : "/lib"
    }]
}