Android Hidl开发_安卓 hidl

1、环境准备

首先准备一份Android源码。

    #源码中编译生成hidl-gen

    make hidl-gen

下面是hidl-gen的语法：

    usage: hidl-gen [-p <root path>] -o <output path> -L <language> [-O <owner>] (-r <interface root>)+ [-R] [-v] [-d <depfile>] FQNAME...

    Process FQNAME, PACKAGE(.SUBPACKAGE)*@[0-9]+.[0-9]+(::TYPE)?, to create output.

    -h: Prints this menu.
    -L <language>: The following options are available:
    check : Parses the interface to see if valid but doesn't write any files.
    c++ : (internal) (deprecated) Generates C++ interface files for talking to HIDL interfaces.
    c++-headers : (internal) Generates C++ headers for interface files for talking to HIDL interfaces.
    c++-sources : (internal) Generates C++ sources for interface files for talking to HIDL interfaces.
    export-header : Generates a header file from @export enumerations to help maintain legacy code.
    c++-impl : Generates boilerplate implementation of a hidl interface in C++ (for convenience).
    c++-impl-headers: c++-impl but headers only.
    c++-impl-sources: c++-impl but sources only.
    c++-adapter : Takes a x.(y+n) interface and mocks an x.y interface.
    c++-adapter-headers: c++-adapter but helper headers only.
    c++-adapter-sources: c++-adapter but helper sources only.
    c++-adapter-main: c++-adapter but the adapter binary source only.
    java : (internal) Generates Java library for talking to HIDL interfaces in Java.
    java-constants : (internal) Like export-header but for Java (always created by -Lmakefile if @export exists).
    vts : (internal) Generates vts proto files for use in vtsd.
    makefile : (removed) Used to generate makefiles for -Ljava and -Ljava-constants.
    androidbp : (internal) Generates Soong bp files for -Lc++-headers, -Lc++-sources, -Ljava, -Ljava-constants, and -Lc++-adapter.
    androidbp-impl : Generates boilerplate bp files for implementation created with -Lc++-impl.
    hash : Prints hashes of interface in `current.txt` format to standard out.
    function-count : Prints the total number of functions added by the package or interface.
    dependencies : Prints all depended types.
    -O <owner>: The owner of the module for -Landroidbp(-impl)?.
    -o <output path>: Location to output files.
    -p <root path>: Android build root, defaults to $ANDROID_BUILD_TOP or pwd.
    -R: Do not add default package roots if not specified in -r.
    -r <package:path root>: E.g., android.hardware:hardware/interfaces.
    -v: verbose output.
    -d <depfile>: location of depfile to write to.

2、创建hidl

在vendor/qcom/proprietary/interfaces下创建howie目录，在howie下创建1.0目录，在1.0目录下创建接口IHowie.hal，包名设置为自定义vendor.oem.hardware.howie的创建目录default。

    package vendor.qcom.hardware.howie@1.0;
     
    interface IHowie{
        helloWorld(string name) generates (string result);
    };

这时候，目录结构为：

    howie/

    └── 1.0

        ├── default

        └── IHowie.hal

在1.0下写一个hidl-gen.sh脚本

    # -o <output path>: Location to output files.
    # -r <package:path root>: E.g., android.hardware:hardware/interfaces.
    # -L <language>
    #   androidbp : (internal) Generates Soong bp files for -Lc++-headers, -Lc++-sources, -Ljava, -Ljava-constants, and -Lc++-adapter.
    #   androidbp-impl : Generates boilerplate bp files for implementation created with -Lc++-impl.
    #   c++-impl : Generates boilerplate implementation of a hidl interface in C++ (for convenience).
     
    PACKAGE=vendor.qcom.hardware.howie@1.0
    LOC=default
    # 生成Android.bp
    hidl-gen -L androidbp -r vendor.qcom.hardware:vendor/qcom/proprietary/interfaces -r android.hidl:system/libhidl/transport $PACKAGE
    # 生成Android.bp
    hidl-gen -o $LOC -L androidbp-impl -r vendor.qcom.hardware:vendor/qcom/proprietary/interfaces -r android.hidl:system/libhidl/transport $PACKAGE
    # 生成C++文件
    hidl-gen -o $LOC -L c++-impl -r vendor.qcom.hardware:vendor/qcom/proprietary/interfaces -r android.hidl:system/libhidl/transport $PACKAGE
     

运行后，目录结构为：

    .
    └── 1.0
        ├── Android.bp
        ├── default
        │   ├── Android.bp
        │   ├── Howie.cpp
        │   └── Howie.h
        ├── hidl-gen.sh
        └── IHowie.hal

    2 directories, 6 files

1.0目录下的Android.bp

    // This file is autogenerated by hidl-gen -Landroidbp.
     
    hidl_interface {
        name: "vendor.qcom.hardware.howie@1.0",
        root: "vendor.qcom.hardware",
        system_ext_specific: true,
        srcs: [
            "IHowie.hal",
        ],
        interfaces: [
            "android.hidl.base@1.0",
        ],
        gen_java: true,
    }

我们稍作修改

    // This file is autogenerated by hidl-gen -Landroidbp.
     
    hidl_interface {
        name: "vendor.qcom.hardware.howie@1.0",
        root: "vendor.qcom.hardware.howie",
        required: ["manifest_vendor.qcom.hardware.howie.xml"],
        //vendor: true,
        srcs: [
            "IHowie.hal",
        ],
        interfaces: [
            "android.hidl.base@1.0",
        ],
        gen_java: true,
    }

1.0/default目录下的Android.bp

    // FIXME: your file license if you have one
     
    cc_library_shared {
        // FIXME: this should only be -impl for a passthrough hal.
        // In most cases, to convert this to a binderized implementation, you should:
        // - change '-impl' to '-service' here and make it a cc_binary instead of a
        //   cc_library_shared.
        // - add a *.rc file for this module.
        // - delete HIDL_FETCH_I* functions.
        // - call configureRpcThreadpool and registerAsService on the instance.
        // You may also want to append '-impl/-service' with a specific identifier like
        // '-vendor' or '-<hardware identifier>' etc to distinguish it.
        name: "vendor.qcom.hardware.howie@1.0-impl",
        relative_install_path: "hw",
        // FIXME: this should be 'vendor: true' for modules that will eventually be
        // on AOSP.
        proprietary: true,
        srcs: [
            "Howie.cpp",
        ],
        shared_libs: [
            "libhidlbase",
            "libutils",
            "vendor.qcom.hardware.howie@1.0",
        ],
    }

稍作修改

    cc_library_shared {
        // FIXME: this should only be -impl for a passthrough hal.
        // In most cases, to convert this to a binderized implementation, you should:
        // - change '-impl' to '-service' here and make it a cc_binary instead of a
        //   cc_library_shared.
        // - add a *.rc file for this module.
        // - delete HIDL_FETCH_I* functions.
        // - call configureRpcThreadpool and registerAsService on the instance.
        // You may also want to append '-impl/-service' with a specific identifier like
        // '-vendor' or '-<hardware identifier>' etc to distinguish it.
        name: "vendor.qcom.hardware.howie@1.0-impl",
        //relative_install_path: "hw",
        // FIXME: this should be 'vendor: true' for modules that will eventually be
        // on AOSP.
        vendor: true,
        srcs: [
            "Howie.cpp",
        ],
        shared_libs: [
            "libhidlbase",
            "libutils",
            "vendor.qcom.hardware.howie@1.0",
        ],
    }

Howie.h

    // FIXME: your file license if you have one
     
    #pragma once
     
    #include <vendor/qcom/hardware/howie/1.0/IHowie.h>
    #include <hidl/MQDescriptor.h>
    #include <hidl/Status.h>
     
    namespace vendor::qcom::hardware::howie::implementation {
     
    using ::android::hardware::hidl_array;
    using ::android::hardware::hidl_memory;
    using ::android::hardware::hidl_string;
    using ::android::hardware::hidl_vec;
    using ::android::hardware::Return;
    using ::android::hardware::Void;
    using ::android::sp;
     
    struct Howie : public V1_0::IHowie {
        // Methods from ::vendor::qcom::hardware::howie::V1_0::IHowie follow.
        Return<void> helloWorld(const hidl_string& name, helloWorld_cb _hidl_cb) override;
     
        // Methods from ::android::hidl::base::V1_0::IBase follow.
     
    };
     
    // FIXME: most likely delete, this is only for passthrough implementations
    // extern "C" IHowie* HIDL_FETCH_IHowie(const char* name);
     
    }  // namespace vendor::qcom::hardware::howie::implementation

Howie.cpp

    // FIXME: your file license if you have one
     
    #include "Howie.h"
     
    namespace vendor::qcom::hardware::howie::implementation {
     
    // Methods from ::vendor::qcom::hardware::howie::V1_0::IHowie follow.
    Return<void> Howie::helloWorld(const hidl_string& name, helloWorld_cb _hidl_cb) {
        // TODO implement
        return Void();
    }
     
     
    // Methods from ::android::hidl::base::V1_0::IBase follow.
     
    //IHowie* HIDL_FETCH_IHowie(const char* /* name */) {
        //return new Howie();
    //}
    //
    }  // namespace vendor::qcom::hardware::howie::implementation

如上面的注释所说，如果将下面的几行注释去掉，hidl将采用直通式通信方式。

    // extern "C" IHowie* HIDL_FETCH_IHowie(const char* name);

    //IHowie* HIDL_FETCH_IHowie(const char* /* name */) {
        //return new Howie();
    //}

下面，润色一下Howie.cpp

    // FIXME: your file license if you have one
     
    #include "Howie.h"
     
    namespace vendor::qcom::hardware::howie::implementation {
     
    // Methods from ::vendor::qcom::hardware::howie::V1_0::IHowie follow.
    Return<void> Howie::helloWorld(const hidl_string& name, helloWorld_cb _hidl_cb) {
        char buf[128];
        ::memset(buf, 0, 128);
        ::snprintf(buf, 128, "Hello World, %s", name.c_str());
        hidl_string result(buf);
     
        _hidl_cb(result);
        return Void();
    }
     
     
    // Methods from ::android::hidl::base::V1_0::IBase follow.
     
    //IHowie* HIDL_FETCH_IHowie(const char* /* name */) {
        //return new Howie();
    //}
    //
    }  // namespace vendor::qcom::hardware::howie::implementation

我希望hidl接口和实现都编译到vendor分区，因此需要做出一点改动：

    vendor.qcom.hardware.howie@1.0的root修改为"vendor.qcom.hardware.howie"；

    将1.0/Android.bp的"system_ext_specific: true,"改成"vendor: true,"；

    将1.0/default/Android.bp的"proprietary: true,"改成"vendor: true,"，后面碰到编译问题，这一行可以注释掉；

    vendor.qcom.hardware.howie@1.0-impl移除relative_install_path: "hw"，因为会碰到找不到该动态库的问题；

除此以外，在howie目录下新增Android.bp

    subdirs = [
        "1.0",
    ]
     
    hidl_package_root {
        name: "vendor.qcom.hardware.howie",
        path: "vendor/qcom/proprietary/interface/howie",
    }

3、构建service

为了能调用到先前创建的hidl接口，我们在default下面再创建一个service.cpp，通过直通式注册服务。

    #define LOG_TAG "vendor.qcom..hardware.howie@1.0-service"
     
    #include <vendor/qcom/hardware/howie/1.0/IHowie.h>
    #include <hidl/LegacySupport.h>
     
    using vendor::qcom::hardware::howie::V1_0::IHowie;
    using android::hardware::defaultPassthroughServiceImplementation;
     
    int main() {
        return defaultPassthroughServiceImplementation<IHowie>(10);//10表示与/dev/hwbinder通信的最大的线程数
    }

绑定式写法：

    #define LOG_TAG "vendor.qcom..hardware.howie@1.0-service"
     
    #include <utils/Log.h>
    #include "android/log.h"
    #include <hidl/HidlSupport.h>
    #include <hidl/HidlTransportSupport.h>
    #include <utils/String16.h>
    #include <vendor/qcom/hardware/howie/1.0/IHowie.h>
    #include <hidl/LegacySupport.h>
    #include "Howie.h"
     
    using vendor::qcom::hardware::howie::V1_0::IHowie;
    using vendor::qcom::hardware::howie::implementation::Howie;
    using android::hardware::configureRpcThreadpool;
    using android::hardware::joinRpcThreadpool;
    using android::sp;
    using android::status_t;
    using android::OK;
     
    int main() {
        configureRpcThreadpool(10, true);
     
        sp<IHowie> howie = new Howie();
        status_t status = howie->registerAsService();
        LOG_ALWAYS_FATAL_IF(status != OK, "Could not register IHowie");
     
        // other interface registration comes here
        joinRpcThreadpool();
        return 0;
    }

同时在default目录下创建rc文件——vendor.qcom.hardware.howie@1.0-service.rc，用于启动vendor.qcom..hardware.howie@1.0-service。

    service howie_service /vendor/bin/hw/vendor.qcom.hardware.howie@1.0-service
        class hal
        user system
        group system

由于新增了两个文件，想要将这两个文件也编进系统，需要再次编辑1.0/default下的Android.bp，如下为新增的：

    //新增如下
    cc_binary {
        name: "vendor.qcom.hardware.howie@1.0-service",
        defaults: ["hidl_defaults"],
        vendor: true,
        relative_install_path: "hw",
        srcs: ["service.cpp"],
        init_rc: ["vendor.qcom.hardware.howie@1.0-service.rc"],
        shared_libs: [
                "libhidlbase",
                "libhidltransport",
                "libutils",
                "liblog",
                "vendor.qcom.hardware.howie@1.0",
                "vendor.qcom.hardware.howie@1.0-impl",
            ],
    }

4、设备清单和框架清单

为了能为server被client访问到，在howie目录下新增目录vintf，在vintf目录下新增设备清单manifest_vendor.qcom.hardware.howie.xml和框架清单vendor_framework_compatibility_matrix.xml。

    <manifest version="1.0" type="device">
        <!-- Howie service-->
        <hal format="hidl">
            <name>vendor.qcom.hardware.howie</name>
            <transport>hwbinder</transport>
            <version>1.0</version>
            <interface>
                <name>IHowie</name>
                <instance>default</instance>
            </interface>
        </hal>
    </manifest>

    <compatibility-matrix version="1.0" type="framework">
        <hal format="hidl" optional="true">
            <name>vendor.qcom.hardware.howie</name>
            <impl level="generic"></impl>
            <version>1.0</version>
            <interface>
                <name>IHowie</name>
                <instance>default</instance>
            </interface>
        </hal>
    </compatibility-matrix>

将两个清单文件加入编译，新增vendor_framework_compatibility_matrix.mk

    DEVICE_FRAMEWORK_COMPATIBILITY_MATRIX_FILE += \
        vendor/qcom/proprietary/interface/howie/vintf/vendor_framework_compatibility_matrix.xml

新增Android.bp

    prebuilt_etc_xml {
        name: "manifest_vendor.qcom.hardware.howie.xml",
        src: "manifest_vendor.qcom.hardware.howie.xml",
        vendor: true,
        installable: true,
        sub_dir: "vintf/manifest",
    }

同时，为了vintf下新增的vendor_framework_compatibility_matrix.mk被编译到，在howie目录下新增Android.mk

    LOCAL_PATH := $(call my-dir)
     
    include $(call all-makefiles-under,$(LOCAL_PATH))

将vintf也加入到howie下的Android.bp

    subdirs = [
        "1.0",
        "vintf",
    ]

5、新增测试client

在1.0目录下新增test目录，在test下面新增如下文件：

HowieTest.cpp

    #include <vendor/qcom/hardware/howie/1.0/IHowie.h>
    #include <hidl/Status.h>
    #include <hidl/LegacySupport.h>
    #include <utils/misc.h>
    #include <hidl/HidlSupport.h>
    #include <stdio.h>
     
    using ::android::hardware::hidl_string;
    using ::android::sp;
    using vendor::qcom::hardware::howie::V1_0::IHowie;
     
    int main(){
        android::sp<IHowie> service = IHowie::getService();
        if (service == nullptr){
            printf("Failed to get service\n");
            return -1;
        }
     
        service->helloWorld("Howie", [&](hidl_string result){
            printf("%s\n", result.c_str());
        });
        return 0;
    }

Android.bp

    cc_binary {
        name: "howie_client",
        defaults: ["hidl_defaults"],
        vendor: true,
        relative_install_path: "hw",
        srcs: ["HowieTest.cpp"],
     
        shared_libs: [
            "liblog",
            "libhardware",
            "libhidlbase",
            "libhidltransport",
            "libutils",
            "vendor.qcom.hardware.howie@1.0",
        ],
     
    }

重新修改目录howie下的Android.bp，将test加入其中。

    subdirs = [
        "1.0",
        "vintf",
        "test",
    ]

 6、编译

    mmm vendor/qcom/proprietary/interfaces/howie

按照之前的编译规则，我们可以在以下的路径中找到编译产物，out/target/product/${PRODUCT}/下，找到这些产物后，push到手机对应目录下即可：

    /vendor/lib64/vendor.qcom.hardware.howie@1.0.so

    /vendor/lib64/vendor.qcom.hardware.howie@1.0-impl.so

    /vendor/bin/hw/vendor.qcom.hardware.howie@1.0-service

    /vendor/etc/init/vendor.qcom.hardware.howie@1.0-service.rc

    /vendor/etc/vintf/manifest/manifest_vendor.qcom.hardware.howie.xml

产物vendor_framework_compatibility_matrix.xml没找到，需要将手机中的/vendor/etc/vintf/compatibility_matrix.xml手动pull出来，然后添加以下内容，并push手机中原文件位置处。

        <hal format="hidl" optional="true">
            <name>vendor.qcom.hardware.howie</name>
            <impl level="generic"></impl>
            <version>1.0</version>
            <interface>
                <name>IHowie</name>
                <instance>default</instance>
            </interface>
        </hal>

7、运行测试

上述文件全部push后重启手机。重启后，在终端模拟器中做如下操作：

    #获取root权限

    adb root

    #运行service

    adb shell

    cd vendor/bin/hw

    ./vendor.qcom.hardware.howie@1.0-service

另起一个终端模拟器

    adb shell

    cd vendor/bin/hw

    ./howie_client

这时候，终端模拟器会打印信息：

    Hello World, Howie

8、添加HIDL接口的hash值

上述添加hidl接口后，会报VTS问题，这时候需要添加hidl接口的hash值

通过修改hidl-gen.sh，注意，这里需要将之前的生成C++文件和bp文件的语句注释掉，否则前面写的内容就全部没了。

    # -o <output path>: Location to output files.
    # -r <package:path root>: E.g., android.hardware:hardware/interfaces.
    # -L <language>
    #   androidbp : (internal) Generates Soong bp files for -Lc++-headers, -Lc++-sources, -Ljava, -Ljava-constants, and -Lc++-adapter.
    #   androidbp-impl : Generates boilerplate bp files for implementation created with -Lc++-impl.
    #   c++-impl : Generates boilerplate implementation of a hidl interface in C++ (for convenience).
     
    PACKAGE=vendor.qcom.hardware.howie@1.0
    # 生成Android.bp
    #hidl-gen -Landroidbp -rvendor.qcom.hardware.howie:vendor/qcom/proprietary/interfaces/howie -randroid.hidl:system/libhidl/transport $PACKAGE
    #LOC=default
    # 生成C++文件
    #hidl-gen -o $LOC -Lc++-impl -rvendor.qcom.hardware:vendor/qcom/proprietary/interfaces -randroid.hidl:system/libhidl/transport $PACKAGE
    # 生成Android.bp
    #hidl-gen -o $LOC -Landroidbp-impl -rvendor.qcom.hardware:vendor/qcom/proprietary/interfaces -randroid.hidl:system/libhidl/transport $PACKAGE
    CURRENT_PATH="$(dirname $(readlink -f "$0"))"
    CURRENT_FILE="${CURRENT_PATH}/../current.txt"
    if [ ! -f ${CURRENT_FILE} ]
    then
        touch ${CURRENT_FILE}
    fi
    hidl-gen -Lhash -rvendor.qcom.hardware.howie:vendor/qcom/proprietary/interfaces/howie $PACKAGE >> ${CURRENT_FILE}

然后运行脚本，就会在vendor/qcom/proprietary/interfaces/howie下看到current.txt文件了

    9c2be150b345854b44ea713cbd64ea64e45932f78ff30770e736286100df5777 vendor.qcom.hardware.howie@1.0::IHowie

9、资源链接

androidhidlhowie.zip-Android文档类资源-CSDN下载

参考文章：

[1] HIDL最全编译流程_Gunder的博客-CSDN博客_hidl编译

[2] https://www.jianshu.com/p/fd73ab98e423

[3] https://www.jianshu.com/p/ca6823b897b5

[4] Android P HIDL服务绑定模式与直通模式的分析 (原创) - five.li - 博客园

[5] 添加HIDL接口hash值（解VTS问题）_JoggingPig的博客-CSDN博客

原文链接：https://blog.csdn.net/hihan_5/article/details/118550429