Additional resources

The following resources provide details on code locations, tools, testing, and licensing.

Queryable code location

The code for the queryable vendor interface object goes to system/libvintf.

Handwriting manifest files and compatibility matrixes can be tough. Use the following tools to generate a boilerplate manifest/compatibility matrix to start from.

LSHAL

LSHAL is a device-side tool that lists all registered HALs to hwservicemanager and all available passthrough implementations (e.g. android.hardware.foo@1.0-impl.so) on the device. It can also generate a device manifest file based on the list:

adb shell su 0 /system/bin/lshal --init-vintf

Note the following:

  1. If a package is both registered to hwservicemanager and found as a passthrough HAL, <transport> is set to hwbinder.
  2. No SELinux version is written into the manifest. It is suggested that the element is injected through assemble_vintf as explained below.
  3. The generated HAL manifest file may be inaccurate. Human attention is required to fix inconsistencies between the device manifest and what vendor.img actually provides.

ASSEMBLE_VINTF

assemble_vintf is a host-side tool that:

  1. Verifies a compatibility matrix or manifest file is valid.
  2. Injects variables to manifests/compatibility matrixes available at build time and generates a new file that should be installed to the device.
  3. Checks compatibility between the generated file and its dual.
  4. If a manifest file is given, optionally generates a boilerplate compatibility matrix that is compatible with the manifest file.

Example: Generate device compatibility matrix from a framework manifest file

assemble_vintf -m --hals-only \
    -i system/libhidl/manifest.xml \
    -o device/manufacturer/device_name/compatibility_matrix.xml

Note that all HALs are set to optional="true".

Example: Generate a skeleton framework compatibility matrix from a device manifest file

assemble_vintf -m --hals-only \
    -i device/foo/bar/manifest.xml \
    -o path/to/place/output/compatibility_matrix.xml

Note that all HALs are set to optional="true".

Example: Generate device manifest XML files from variables

At build time, if the following variables are defined in device/manufacturer/device_name/BoardConfig.mk:

# Vendor manifest is named DEVICE_MANIFEST_FILE for legacy reasons.
DEVICE_MANIFEST_FILE := \
    device/manufacturer/device_name/vendor_manifest.xml
ODM_MANIFEST_FILES := \
    device/manufacturer/device_name/odm_manifest.xml
ODM_MANIFEST_SKUS := sku1 sku2
ODM_MANIFEST_SKU1_FILES := \
    device/manufacturer/device_name/odm_manifest_sku1.xml
ODM_MANIFEST_SKU2_FILES := \
    device/manufacturer/device_name/odm_manifest_sku2.xml

Then the following commands are executed (in the build system, modified to omit implementation details) to generate device manifest XML files:

# vendor manifest; only when DEVICE_MANIFEST_FILE is set
BOARD_SEPOLICY_VERS=$(BOARD_SEPOLICY_VERS) assemble_vintf \
    $(addprefix,-i ,$(DEVICE_MANIFEST_FILE)) \
    -o $(TARGET_OUT_VENDOR)/etc/vintf/manifest.xml

# ODM manifests
assemble_vintf \
    $(addprefix,-i ,$(ODM_MANIFEST_FILES)) \
    -o $(TARGET_OUT_ODM)/etc/vintf/manifest.xml

# ODM manifests for each sku
assemble_vintf \
    $(addprefix,-i ,$(ODM_MANIFEST_SKU1_FILES)) \
    -o $(TARGET_OUT_ODM)/etc/vintf/manifest_sku1.xml
assemble_vintf \
    $(addprefix,-i ,$(ODM_MANIFEST_SKU2_FILES)) \
    -o $(TARGET_OUT_ODM)/etc/vintf/manifest_sku2.xml

At runtime, the VINTF object combines vendor manifests and ODM manifests as the device manifest. See Device manifest for details.

Example: Generate device compatibility matrix XML files from variables

At build time, if the following variables are defined in device/manufacturer/device_name/BoardConfig.mk:

# vendor compatibility matrix is named DEVICE_MATRIX_FILE for legacy reasons.
DEVICE_MATRIX_FILE := \
    device/manufacturer/device_name/vendor_compatibility_matrix.xml \
    device/manufacturer/device_name/vendor_compatibility_matrix_additional.xml

Then the following commands are executed (in the build system, modified to omit implementation details) to generate device compatibility matrix XML files:

# vendor compatibility matrix; only when DEVICE_MATRIX_FILE is set
assemble_vintf \
    $(addprefix,-i ,$(DEVICE_MATRIX_FILE)) \
    -o $(TARGET_OUT_VENDOR)/etc/vintf/compatibility_matrix.xml

At runtime, the VINTF object uses the vendor compatibility matrix as the device compatibility matrix. See Device compatibility matrix for details.

Example: Generate framework manifest XML files from variables

The following variables may be defined in device/manufacturer/device_name/BoardConfig.mk:

# Device-specific system manifest is named DEVICE_FRAMEWORK_MANIFEST_FILE for legacy reasons
DEVICE_FRAMEWORK_MANIFEST_FILE := \
    device/manufacturer/device_name/device_system_manifest.xml

# Product manifest
PRODUCT_MANIFEST_FILES := \
    device/manufacturer/device_name/product_manifest.xml

The following commands are executed (in the build system, modified to omit implementation details) to generate framework manifest XML files:

# system manifest
assemble_vintf \
    -i system/libhidl/vintfdata/manifest.xml \
    $(addprefix,-i ,$(DEVICE_FRAMEWORK_MANIFEST_FILE)) \
    -o $(TARGET_OUT)/etc/vintf/manifest.xml

# product manifest
assemble_vintf \
    $(addprefix,-i ,$(PRODUCT_MANIFEST_FILES)) \
    -o $(TARGET_OUT_PRODUCT)/etc/vintf/manifest.xml

At runtime, the VINTF object combines the system manifest, system manifest fragments, product manifest, and product manifest fragments as the framework manifest. See Framework manifest for details.

Example: Generate framework compatibility matrix XML files from variables

The following variables may be defined in device/manufacturer/device_name/BoardConfig.mk to define the product FCM and device-specific system FCM:

DEVICE_PRODUCT_COMPATIBILITY_MATRIX_FILE := \
    device/manufacturer/device_name/product_compatibility_matrix.xml
# Device-specific system compatibility matrix is named
# DEVICE_FRAMEWORK_COMPATIBILITY_MATRIX_FILE for legacy reasons.
DEVICE_FRAMEWORK_COMPATIBILITY_MATRIX_FILE := \
    device/manufacturer/device_name/device_system_compatibility_matrix.xml

The system_ext FCM must be installed with Soong modules. The product FCM may also be installed with Soong modules; do not define DEVICE_PRODUCT_COMPATIBILITY_MATRIX_FILE if this method is used. In addition, multiple product FCM versions and system_ext FCM versions may be installed with Soong modules. Define the following:

  • Define a module in device/manufacturer/device_name/Android.bp. For example (replace system_ext with product for product FCM): 
    vintf_compatibility_matrix {
    name: "system_ext_compatibility_matrix.xml",
    stem: "compatibility_matrix.xml",
    system_ext_specific: true,
    // product_specific: true, // for product FCM
    srcs: [
        "system_ext_compatibility_matrix.xml",
    ],
}
  • Install the module to device/manufacturer/device_name/device.mk. For example: 
    PRODUCT_PACKAGES += system_ext_compatibility_matrix.xml

The following commands are executed (in the build system, modified to omit implementation details) to generate framework compatibility matrix XML files:

# common system compatibility matrix for each FCM version
BOARD_SEPOLICY_VERS=$(BOARD_SEPOLICY_VERS) \
POLICYVERS=$(POLICYVERS) \
BOARD_AVB_VBMETA_VERSION=$(BOARD_AVB_VBMETA_VERSION)
assemble_vintf \
    -i hardware/interfaces/compatibility_matrices/compatibility_matrix.empty.xml
    $(addprefix,-i ,$(DEVICE_FRAMEWORK_COMPATIBILITY_MATRIX_FILE)) \
    -o $(TARGET_OUT)/etc/vintf/compatibility_matrix.device.xml

# framework compatibility matrixes at each FCM version
assemble_vintf
    -i hardware/interfaces/compatibility_matrices/compatibility_matrix.{level}.xml \
    -o $(TARGET_OUT)/etc/vintf/compatibility_matrix.{level}.xml \
    --kernel=...

# product framework compatibility matrix; only when
# DEVICE_PRODUCT_COMPATIBILITY_MATRIX_FILE is set or when the Soong module for
# product FCM is defined
assemble_vintf
    -i $(DEVICE_PRODUCT_COMPATIBILITY_MATRIX_FILE)
    -o $(TARGET_OUT_PRODUCT)/etc/vintf/compatibility_matrix.xml

# system_ext framework compatibility matrix; only when the Soong module for
# system_ext FCM is defined
assemble_vintf
    -i <srcs for the soong module>
    -o $(TARGET_OUT_SYSTEM_EXT)/etc/vintf/compatibility_matrix.xml

At runtime, the VINTF object combines a subset of system compatibility matrixes and product compatibility matrixes as the framework compatibility matrix. See Framework compatibility matrix for details.

Example: Generate the vendor manifest from fragments

Multiple vendor manifest fragments can be bundled at build time. For example:

<!-- device/manufacturer/device_name/manifest_common.xml -->
<manifest version="1.0" type="device">
    <!-- common HALs here -->
</manifest>
 
<!-- device/manufacturer/device_name/ir.xml -->
<manifest version="1.0" type="device">
    <hal>
        <name>android.hardware.ir</name>
        <version>1.0</version>
        <!-- other fields -->
    </hal>
</manifest>
 
# device/manufacturer/device_name/BoardConfig.mk
DEVICE_MANIFEST_FILE := device/manufacturer/device_name/manifest_common.xml
ifdef BOARD_ENABLE_IR
    DEVICE_MANIFEST_FILE += device/manufacturer/device_name/ir.xml
endif

Then, assemble_vintf adds the IR HAL to the vendor manifest if BOARD_ENABLE_IR is defined, and omits it if BOARD_ENABLE_IR is not defined. The following commands (modified to omit implementation details) are executed to generate the vendor manifest:

# if BOARD_ENABLE_IR is defined
BOARD_SEPOLICY_VERS=10000.0 assemble_vintf \
    -i device/manufacturer/device_name/manifest_common.xml:device/manufacturer/device_name/ir.xml \
    -o $(TARGET_OUT_VENDOR)/manifest.xml

# if BOARD_ENABLE_IR is not defined
BOARD_SEPOLICY_VERS=10000.0 assemble_vintf \
    -i device/manufacturer/device_name/manifest_common.xml \
    -o $(TARGET_OUT_VENDOR)/manifest.xml

For details, see:

assemble_vintf --help

Testing

The platform/system/libvintf project uses GTest for the serialization, deserialization, and compatibility checking.

Licensing

  • tinyxml2 (external/tinyxml2) for serializing/deserializing the object to/from XML. BSD-like license.
  • libselinux (external/selinux/libselinux) for getting policydb version. Public domain license.
  • libz (external/zlib) for decompressing /proc/config.gz. BSD-like license.
  • libvintf project uses Apache 2.0 license (with appropriate MODULE_LICENSE_APACHE2 and NOTICE files).