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 liblogLOCAL_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 := trueLOCAL_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 { } ：指明编译的是动态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 ：引用的其他动态 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 := platformLOCAL_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 := trueLOCAL_JAVA_LIBRARIES := \xxx-framework \LOCAL_STATIC_JAVA_LIBRARIES += \SettingsLibinclude $(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 := platformLOCAL_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 := trueLOCAL_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 ################