Andorid 使用bp或者mk编译C文件生成so

在Aosp源码里编译C文件生成so

使用mk编译

文件夹列表

CMkDemo/Android.mk
CMkDemo/cpp/SerialPort.c
CMkDemo/cpp/SerialPort.h

Android.mk 内容如下

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)

LOCAL_MODULE_TAGS := optional

# All of the source files that we will compile.
LOCAL_SRC_FILES:= \
  cpp/SerialPort.c

# All of the shared libraries we link against.
LOCAL_SHARED_LIBRARIES := \
	libutils liblog

LOCAL_HEADER_LIBRARIES += jni_headers

# No static libraries.
LOCAL_STATIC_LIBRARIES :=

# Also need the JNI headers.
#LOCAL_C_INCLUDES += \
#	$(JNI_H_INCLUDE)

# This is the target being built.
LOCAL_MODULE:= lib_cmkdemo
LOCAL_SYSTEM_EXT_MODULE := true

LOCAL_MULTILIB := 64

# No special compiler flags.
LOCAL_CFLAGS +=

include $(BUILD_SHARED_LIBRARY)

最终生成 ./out/target/product/<device_name>/system/system_ext/lib64/lib_cmkdemo.so

如果去掉 LOCAL_MULTILIB := 64 ，会生成
./out/target/product/<device_name>/system/system_ext/lib/lib_cmkdemo.so
./out/target/product/<device_name>/system/system_ext/lib64/lib_cmkdemo.so

使用bp编译

文件夹列表

CBpDemo/Android.bp
CBpDemo/cpp/SerialPort.c
CBpDemo/cpp/SerialPort.h

Android.bp 内容如下

cc_library_shared {
    name: "lib_cbpdemo",
	system_ext_specific: true,
	compile_multilib: "64",
    srcs: [
        "cpp/*.c",
        "cpp/*.cpp",
    ],
    include_dirs: [
    ],
	header_libs: [
        "jni_headers",
    ],

    shared_libs: [
        "liblog",
    ]
}

• 行首空一行，否则编译报错 error: missing separator. ；
• cc_library_shared { } ：指明编译的是静态so库；
• name: “lib_cbpdemo” ：指明 module 名是 lib_cbpdemo ，最终会生成 lib_cbpdemo.so ；
• system_ext_specific: true ：编译产物在 system_ext 分区，本例对应 ./out/target/product/<device_name>/system/system_ext/lib64/lib_cbpdemo.so ；
• compile_multilib ：指明编译的是 32 还是 64 位的；
• srcs ：源码文件夹或者路径，多个层级可以用类似写法 src/**/*.c ；
• include_dirs ：引用外部的源文件，要写完整路径；
• header_libs ：
• shared_libs ：引用的其他静态 so 库，本例引用的是 liblog.so ；

编译生成的so给其他module引用

场景： 需要把C文件集成到 Test.apk 的源码里，编译生成的 Test.apk 里有对应的 lib_xx.so ，

Android.mk

Test.apk 的 Android.mk ，

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)

LOCAL_PACKAGE_NAME := Test
LOCAL_MODULE_TAGS := optional
LOCAL_CERTIFICATE := platform

LOCAL_SRC_FILES := $(call all-java-files-under, src)

LOCAL_DEX_PREOPT := false
LOCAL_SYSTEM_EXT_MODULE := true
LOCAL_PROGUARD_FLAG_FILES := proguard.flags
LOCAL_PRIVATE_PLATFORM_APIS := true
LOCAL_PRIVILEGED_MODULE := true

LOCAL_JAVA_LIBRARIES := \
	xxx-framework \

LOCAL_STATIC_JAVA_LIBRARIES += \
	SettingsLib

include $(BUILD_PACKAGE)

把 C 文件放到 src/com/test/cpp/ 下，添加 patch 如下，

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)

LOCAL_PACKAGE_NAME := Test
LOCAL_MODULE_TAGS := optional
LOCAL_CERTIFICATE := platform

LOCAL_SRC_FILES := $(call all-java-files-under, src)

LOCAL_DEX_PREOPT := false
LOCAL_SYSTEM_EXT_MODULE := true
LOCAL_PROGUARD_FLAG_FILES := proguard.flags
LOCAL_PRIVATE_PLATFORM_APIS := true
LOCAL_PRIVILEGED_MODULE := true

LOCAL_JAVA_LIBRARIES := \
	xxx-framework \

LOCAL_STATIC_JAVA_LIBRARIES += \
	SettingsLib

############### patch begin ################
LOCAL_JNI_SHARED_LIBRARIES:= lib_cmkdemo
############### patch end ################
include $(BUILD_PACKAGE)

############### patch begin ################
#LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)

LOCAL_MODULE_TAGS := optional

# This is the target being built.
LOCAL_MODULE:= lib_cmkdemo
LOCAL_SYSTEM_EXT_MODULE := true

# All of the source files that we will compile.
LOCAL_SRC_FILES:= \
  src/com/test/cpp/SerialPort.c

# Also need the JNI headers.
LOCAL_C_INCLUDES += \
	$(JNI_H_INCLUDE)

# All of the shared libraries we link against.
LOCAL_SHARED_LIBRARIES := \
	libutils liblog

# No static libraries.
LOCAL_STATIC_LIBRARIES :=

#LOCAL_MULTILIB := 64

# No special compiler flags.
LOCAL_CFLAGS +=

include $(BUILD_SHARED_LIBRARY)
############### patch end ################

Android.bp

Test.apk 的 Android.bp ，

android_app {
    name: "Test",
    certificate: "platform",
    srcs: ["src/**/*.java"],

    dex_preopt: {
        enabled: false,
    },
    system_ext_specific: true,
    optimize: {
        proguard_flags_files: ["proguard.flags"],
    },
    platform_apis: true,
    privileged: true,

    libs: [
        "xxx-framework",
    ],

    static_libs: ["SettingsLib"],
}

把 C 文件放到 src/com/test/cpp/ 下，添加 patch 如下，

android_app {
    name: "Test",
    certificate: "platform",
    srcs: ["src/**/*.java"],
    dex_preopt: {
        enabled: false,
    },
    system_ext_specific: true,
    optimize: {
        proguard_flags_files: ["proguard.flags"],
    },
    platform_apis: true,
    privileged: true,

    libs: [
        "xxx-framework",
    ],

    static_libs: ["SettingsLib"],

//############## patch begin ################
    jni_libs: ["lib_cbpdemo"],
//############## patch end ################
}

//############## patch begin ################
//LOCAL_PATH:= $(call my-dir)
cc_library_shared {

    // This is the target being built.
    name: "lib_cbpdemo",
    system_ext_specific: true,

    // All of the source files that we will compile.
    srcs: ["src/com/test/cpp/SerialPort.c"],

    // Also need the JNI headers.
    include_dirs: JNI_H_INCLUDE,

    // All of the shared libraries we link against.
    shared_libs: [
        "libutils",
        "liblog",
    ],

    // No static libraries.
    static_libs: [],

    //LOCAL_MULTILIB := 64

    // No special compiler flags.
    cflags: [],

}
//############## patch end ################