syspara Module

Introduction

This module provides an easy-to-use key-value pair access interface for system services to configure service functions based on their own system parameters. The following figure shows the basic primitives used to access and operate system parameters.

Figure 1 Operation primitives for system parameters

Table 1 Description of operation primitives

A system parameter name consists of multiple segments in dotted notation. Each segment consists of letters, digits, and underscores (_). The total length cannot exceed 96 bytes. System parameter names are categorized into the following two types.

Table 2 Naming of system parameters

System parameters are categorized into three types.

Table 3 System parameter types

The naming format of system parameters is as follows: [const|persist].$sub_system.$desc.

$sub_system is the name of the subsystem or module.

$desc indicates the description of a system parameter. The description can contain multiple segments in dotted notation.

System Parameter Definition Rules

Each subsystem defines the system parameters of its own modules, including the system parameter name, default value, and access permission information.

System Parameter Value Definition File

The system parameter value definition file ends with the .para extension. An example of the file format is as follows:

# This is comment
const.product.name=OHOS-PRODUCT
const.os.version.api=26
const.telephony.enable=false|true

const.test.withblank=My Value

Note: System parameter values do not support comments and line breaks.

# Not supported
const.test.withcomment=MyValue # This should be ommitted
# Not supported
const.test.multiline="This is a multiline parameter.
Line2 value.
Last line."

You must use a complete system parameter command when assigning a value for a system parameter. The following table describes the value assignment modes.

Table 4 Value assignment modes

System Parameter DAC Definition File

Currently, access permissions of system parameters are managed in Discretionary Access Control (DAC) mode. The access permission definition file ends with the .para.dac extension. The following is an example:

const.product.="root:root:660"

As shown above, we can use parameter directory to define the same access permission for system parameters with the same prefix. The DAC information is divided into three segments, user, group, and UGO rule information, which are separated using a semicolon (:).

The following figure shows the structure of the UGO rule information.

Figure 2 Rule information

Installation of the System Parameter Definition File

The .para and .para.dac files are installed in the /etc/param/ directory. An example of the GN script is as follows:

ohos_prebuilt_etc("ohos.para") {
    source = "//base/startup/init_lite/services/etc/ohos.para"
    part_name = "init"
    module_install_dir = "etc/param"
}

ohos_prebuilt_etc("ohos.para.dac") {
    source = "//base/startup/init_lite/services/etc/ohos.para.dac"
    part_name = "init"
    module_install_dir = "etc/param"
}

Loading Sequence of the System Parameter Value Definition File

The following table provides the sequence of loading system parameter value definition files.

Table 5 Sequence of loading system parameter value definition files

Usage of Shell Commands

The following table describes the shell commands used to set system parameters.

Table 6 Description of shell commands

Available APIs

Table 7 APIs for the syspara module

How to Use

The following is an example of using syspara.

// set && get
char key1[] = "rw.sys.version";
char value1[] = "10.1.0";
int ret = SetParameter(key1, value1);
char valueGet1[128] = {0};
ret = GetParameter(key1, "version=10.1.0", valueGet1, 128);

// get sysparm
char* value1 = GetDeviceType();
printf("Product type =%s\n", value1);
free(value1);
char* value2 = GetManufacture();
printf("Manufacture =%s\n", value2);
free(value2);
char* value3 = GetBrand();
printf("GetBrand =%s\n", value3);
free(value3);
char* value4 = GetMarketName();
printf("MarketName =%s\n", value4);
free(value4);
char* value5 = GetProductSeries();
printf("ProductSeries =%s\n", value5);
free(value5);
char* value6 = GetProductModel();
printf("ProductModel =%s\n", value6);
free(value6);
char* value7 = GetSoftwareModel();
printf("SoftwareModel =%s\n", value7);
free(value7);
char* value8 = GetHardwareModel();
printf("HardwareModel =%s\n", value8);
free(value8);
char* value9 = GetHardwareProfile();
printf("Software profile =%s\n", value9);
free(value9);
char* value10 = GetSerial();
printf("Serial =%s\n", value10);
free(value10);
char* value11 = GetOSFullName();
printf("OS name =%s\n", value11);
free(value11);
char* value12 = GetDisplayVersion();
printf("Display version =%s\n", value12);
free(value12);
char* value13 = GetBootloaderVersion();
printf("bootloader version =%s\n", value13);
free(value13);
char* value14 = GetSecurityPatchTag();
printf("secure patch level =%s\n", value14);
free(value14);
char* value15 = GetAbiList();
printf("abi list =%s\n", value15);
free(value15);
int value16 = GetFirstApiVersion();
printf("first api level =%d\n", value16);
free(value16);
char* value17 = GetIncrementalVersion();
printf("Incremental version = %s\n", value17);
free(value17);
char* value18 = GetVersionId();
printf("formal id =%s\n", value18);
free(value18);
char* value19 = GetBuildType();
printf("build type =%s\n", value19);
free(value19);
char* value20 = GetBuildUser();
printf("build user =%s\n", value20);
free(value20);
char* value21 = GetBuildHost();
printf("Build host = %s\n", value21);
free(value21);
char* value22 = GetBuildTime();
printf("build time =%s\n", value22);
free(value22);
char* value23 = GetBuildRootHash();
printf("build root later..., %s\n", value23);
free(value23);
char* value24 = GetOsReleaseType();
printf("OS release type =%s\n", value24);
free(value24);
char* value25 = GetOsReleaseType();
printf("OS release type =%s\n", value25);
free(value25);
char value26[65] = {0};
GetDevUdid(value26, 65);
printf("device udid =%s\n", value26);
free(value26);