go调用lib和so动态库

# go 调用dll

# 1. sysCall.LoadDll(推荐使用)

系统调用是程序向操作系统内核请求服务的过程，通常包含硬件相关的服务(例如访问硬盘),创建新进程等。系统调用提供了一个进程和操作系统之间的接口

fmt中的syscall

func Println(a ...interface{}) (n int, err error) {
    return Fprintln(os.Stdout, a...)
}

Stdout = NewFile(uintptr(syscall.Stdout), "/dev/stdout")

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调用dll 示例

dll, err := syscall.LoadDLL("scan.dll")
//根据名称从dll中查找proc
MemoryStream_Get = dll.FindProc("AllocateMemory")
MemoryStream_Get.Call()

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此方式可以也可以调用go 代码打包的dll

# 2. Cgo调用

项目目录结构如下

├── include
│     └── add.c
│     └── add.h
├── lib
│     └── libadd.dll
└── main.go

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add.h

#ifndef __ADD_H__
#define __ADD_H__
 
char* Add(char* src, int n);
 
#endif

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add.c

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
 
char* Add(char* src, int n)
{
    char str[20];
    sprintf(str, "%d", n);
    char *result = malloc(strlen(src)+strlen(str)+1);
    strcpy(result, src);
    strcat(result, str);
    return result;
}

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main.go

func GetFinalStrategyString(request string) {

	dll, err := syscall.LoadDLL("./middleware_c.dll")
	if err != nil {
		log.Fatal("Error loading DLL:", err)
	}
	defer dll.Release()

	getFinalStrategyString, err := dll.FindProc("GetFinalStrategyString")
	if err != nil {
		log.Fatal("Error finding GetFinalStrategyString:", err)
	}

	freeFinalStrategyString, err := dll.FindProc("FreeFinalStrategyString")
	if err != nil {
		log.Fatal("Error finding FreeFinalStrategyString:", err)
	}

	// cRequest, err := syscall.UTF16PtrFromString(request)
	// if err != nil {
	// 	log.Fatal("Error converting request:", err)
	// }

	var cResponse *uint16
	var responseLen uint32

	ret, _, _ := getFinalStrategyString.Call(
		uintptr(unsafe.Pointer(request)),
		uintptr(len(request)),
		uintptr(unsafe.Pointer(&cResponse)),
		uintptr(unsafe.Pointer(&responseLen)),
	)

	if ret != 0 {
		log.Fatal("ret Error:", ret)
	}
	fmt.Println("responseLen:", responseLen)
	fmt.Println("cResponse:", cResponse)

	cResponseBytes := (*[1 << 20]byte)(unsafe.Pointer(cResponse))[:responseLen]
	fmt.Println("cResponseBytes:", cResponseBytes)
}

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# 3. 动态调用 dll （推荐使用）

动态调用步骤
1. 通过文件路径加载c/c++ 动态库中的 handle
2. 在go代码中定义和c/c++ 动态库中对应的go func
3. 使用库purego（底层是dlopen）或者sys/windows 将handle中对应的方法符号（Symbol）映射到 go func 地址上
4. 逻辑调用

main.go

import "C"
import (
	"context"
	"fmt"
	"github.com/ebitengine/purego"
	"sync"
)


var (
	getFinalStrategyString func(*C.char, C.uint, **C.char, *C.uint) C.int  //2. 定义和c/c++ 动态库中对应的go func
	freeFinalStrategyString func(*C.char)  // 2. 定义和c/c++ 动态库中对应的go func
	mcRunModeOnce sync.Once
	mcRunMode     int
)

func main(){
    InitMC(libFilePath)
}

func InitMC(libFilePath string) (err error) {
	defer func() {
		if _err := recover(); _err != nil {
			logger.Errorf("RegisterLibFunc panic error: %v", err)
			err = fmt.Errorf("RegisterLibFunc panic error: %v", err.Error())
		}
	}()
	...
	mcHandle, err := LoadHandle(libFilePath)  // 1. 通过路径加载c/c++ 动态库handle
	if err != nil {
		logger.Errorf("LoadHandle error:%v", err.Error())
		return err
	}
    // 找不到函数会panic
	purego.RegisterLibFunc(&getFinalStrategyString, mcHandle, "GetFinalStrategyString") // 3. 使用库purego将handle中对应的方法映射到go func
	purego.RegisterLibFunc(&freeFinalStrategyString, mcHandle, "FreeFinalStrategyString")  // 3. 使用库purego将handle中对应的方法映射到go func
	return nil
}

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load_linux.go

//go:build !windows
// +build !windows

package main

import "github.com/ebitengine/purego"

const MCLibPath = "c.so"

func LoadHandle(libPath string) (uintptr, error) {
	return purego.Dlopen(libPath, purego.RTLD_NOW|purego.RTLD_GLOBAL)
}

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load_windows.go

//go:build windows
// +build windows

package main

import "golang.org/x/sys/windows"

const MCLibPath = ""

func LoadHandle(libPath string) (uintptr, error) {
	handle, err := windows.LoadLibrary(libPath)
	return uintptr(handle), err
}

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业务调用

c++ 头文件

#ifdef __cplusplus extern "C" { #endif

MIDDLEWARE_C_EXPORT int GetFinalStrategyString( /::browserconsoleapiv3::middle_ware::GetUserStrategiesRequest request/ const char* request, unsigned request_len, /::browserconsoleapiv3::api::user::FinalGroupStrategy response/ char** response, unsigned* response_len);

MIDDLEWARE_C_EXPORT void FreeFinalStrategyString(const char*);

#ifdef __cplusplus } #endif

package middleware

/*
#include <stdlib.h>  // 要引入
*/
import "C"
import (
	"fmt"
	"unsafe"
)

type MiddlewareC struct {
	response *C.char
}

func (mc *MiddlewareC) GetFinalStrategyString(req string) (resByte []byte, err error) {
	cRequest := C.CString(req)
	defer C.free(unsafe.Pointer(cRequest))
	var (
		reqLen      C.uint
		cResponse   *C.char
		responseLen C.uint
		resCodeC    C.int
	)
	reqLen = C.uint(len(req))
	resCodeC = getFinalStrategyString(cRequest, reqLen, &cResponse, &responseLen)  //4. 真正的业务调用
	resCode := int(resCodeC)
	if resCode != 0 {
		errMsg, ok := MCError[resCode]
		if !ok {
			err = fmt.Errorf(
				"unknown error code, code:%v, cResponse: %v, cResponse len: %v",
				resCode, cResponse, responseLen,
			)
		} else {
			err = fmt.Errorf(
				"middleware error msg: %v, error code: %v, cResponse: %v, cResponse len: %v",
				errMsg, resCode, cResponse, responseLen,
			)
		}
		return resByte, err
	}
	resByte = C.GoBytes(unsafe.Pointer(cResponse), C.int(responseLen))
	mc.response = cResponse
	return resByte, nil
}

func (mc *MiddlewareC) MustFreeFinalStrategyString() {
	freeFinalStrategyString(mc.response)
}

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# go 调用so

# 1. Cgo调用

项目目录结构如下

├── include
│     └── add.c
│     └── add.h
├── lib
│     └── libadd.so
└── main.go

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add.h

#ifndef __ADD_H__
#define __ADD_H__
 
char* Add(char* src, int n);
 
#endif

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add.c

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
 
char* Add(char* src, int n)
{
    char str[20];
    sprintf(str, "%d", n);
    char *result = malloc(strlen(src)+strlen(str)+1);
    strcpy(result, src);
    strcat(result, str);
    return result;
}

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linux 下编译

会在当前目录下生成 libadd.so 文件, 在 Linux 下可用 nm -D libadd.so 查看其中的方法
```
gcc -fPIC -shared -o lib/libadd.so include/add.c
```
1

main.go

package main

/*
// 头文件的位置，相对于源文件是当前目录，所以是 .，头文件在多个目录时写多个  #cgo CFLAGS: ...
#cgo CFLAGS: -I./include
// 从哪里加载动态库，位置与文件名，-ladd 加载 libadd.so 文件
#cgo LDFLAGS: -L./lib -ladd -Wl,-rpath,lib
#include "add.h"
*/
import "C"
import "fmt"
 
func main() {
  val := C.Add(C.CString("go"), 2023)
  fmt.Println("run c: ", C.GoString(val))
}

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注意：
- 如果把#cgo LDFLAGS: -L./lib -ladd -Wl,-rpath,lib 改为 cgo LDFLAGS: -L./lib -ladd编译不会报错，执行时会出错
```
error while loading shared libraries: libadd.so: cannot open shared object file: No such file or directory
```
  1
- 设置了环境变量 LD_LIBRARY_PATH=/home/.../lib 也能让它跑起来
```
LD_LIBRARY_PATH=lib/ ./demo
```
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# 2. 动态调用 so（推荐使用）

动态调用步骤
1. 通过路径加载c/c++ 动态库 handle
2. 定义和c/c++ 动态库中对应的go func
3. 使用库purego 将handle中对应的方法映射到go func
4. 逻辑调用

main.go

import "C"
import (
	"context"
	"fmt"
	"github.com/ebitengine/purego"
	"sync"
)


var (
	getFinalStrategyString func(*C.char, C.uint, **C.char, *C.uint) C.int  //2. 定义和c/c++ 动态库中对应的go func
	freeFinalStrategyString func(*C.char)  // 2. 定义和c/c++ 动态库中对应的go func
	mcRunModeOnce sync.Once
	mcRunMode     int
)

func main(){
    InitMC(libFilePath)
}

func InitMC(libFilePath string) (err error) {
	defer func() {
		if _err := recover(); _err != nil {
			logger.Errorf("RegisterLibFunc panic error: %v", err)
			err = fmt.Errorf("RegisterLibFunc panic error: %v", err.Error())
		}
	}()
	...
	mcHandle, err := LoadHandle(libFilePath)  // 1. 通过路径加载c/c++ 动态库handle
	if err != nil {
		logger.Errorf("LoadHandle error:%v", err.Error())
		return err
	}
    // 找不到函数会panic
	purego.RegisterLibFunc(&getFinalStrategyString, mcHandle, "GetFinalStrategyString") // 3. 使用库purego将handle中对应的方法映射到go func
	purego.RegisterLibFunc(&freeFinalStrategyString, mcHandle, "FreeFinalStrategyString")  // 3. 使用库purego将handle中对应的方法映射到go func
	return nil
}

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load_linux.go

//go:build !windows
// +build !windows

package main

import "github.com/ebitengine/purego"

const MCLibPath = "c.so"

func LoadHandle(libPath string) (uintptr, error) {
	return purego.Dlopen(libPath, purego.RTLD_NOW|purego.RTLD_GLOBAL)
}

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load_windows.go

//go:build windows
// +build windows

package main

import "golang.org/x/sys/windows"

const MCLibPath = ""

func LoadHandle(libPath string) (uintptr, error) {
	handle, err := windows.LoadLibrary(libPath)
	return uintptr(handle), err
}

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业务调用

c++ 头文件

#ifdef __cplusplus extern "C" { #endif

MIDDLEWARE_C_EXPORT int GetFinalStrategyString( /::browserconsoleapiv3::middle_ware::GetUserStrategiesRequest request/ const char* request, unsigned request_len, /::browserconsoleapiv3::api::user::FinalGroupStrategy response/ char** response, unsigned* response_len);

MIDDLEWARE_C_EXPORT void FreeFinalStrategyString(const char*);

#ifdef __cplusplus } #endif

package middleware

/*
#include <stdlib.h>  // 要引入
*/
import "C"
import (
	"fmt"
	"unsafe"
)

type MiddlewareC struct {
	response *C.char
}

func (mc *MiddlewareC) GetFinalStrategyString(req string) (resByte []byte, err error) {
	cRequest := C.CString(req)
	defer C.free(unsafe.Pointer(cRequest))
	var (
		reqLen      C.uint
		cResponse   *C.char
		responseLen C.uint
		resCodeC    C.int
	)
	reqLen = C.uint(len(req))
	resCodeC = getFinalStrategyString(cRequest, reqLen, &cResponse, &responseLen)  //4. 真正的业务调用
	resCode := int(resCodeC)
	if resCode != 0 {
		errMsg, ok := MCError[resCode]
		if !ok {
			err = fmt.Errorf(
				"unknown error code, code:%v, cResponse: %v, cResponse len: %v",
				resCode, cResponse, responseLen,
			)
		} else {
			err = fmt.Errorf(
				"middleware error msg: %v, error code: %v, cResponse: %v, cResponse len: %v",
				errMsg, resCode, cResponse, responseLen,
			)
		}
		return resByte, err
	}
	resByte = C.GoBytes(unsafe.Pointer(cResponse), C.int(responseLen))
	mc.response = cResponse
	return resByte, nil
}

func (mc *MiddlewareC) MustFreeFinalStrategyString() {
	freeFinalStrategyString(mc.response)
}

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# 大坑！！！

动态库中的崩溃会直接导致主程序崩溃！！！！！！！！！！

崩溃测试

创建崩溃程序

package main

import "C"
import "fmt"

//export PrintTest
func PrintTest() int {
	defer func() {
		if err := recover(); err != nil {
			print("err\n")
			print(err)
		}
	}()
	print("hello world\n")
	var a []int
	a[0] = 1
	print("hello world 2\n")
	return 1
}

func main() {
	fmt.Println("call cpp test")
}

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打包dll文件go build -o pt.dll -buildmode=c-shared main.go

主程序调用

package main

import "C"
import (
	"github.com/ebitengine/purego"
	win "golang.org/x/sys/windows"
	"log"
)

var PrintTest func() int

func openLibrary(name string) (uintptr, error) {
	handle, err := win.LoadLibrary(name)
	return uintptr(handle), err
}

func main() {
    // recover无效了！
	defer func() {
		if err := recover(); err != nil {
			log.Println("err")
			log.Println(err)
		}
	}()

	lib, err := openLibrary("./dll/pt.dll")
	if err != nil {
		log.Fatalln(err)
	}
	purego.RegisterLibFunc(&PrintTest, lib, "PrintTest")
	res := PrintTest()
	log.Println(res)
}

// ！！！ 直接panic，recover无效

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#Go

上次更新: 2023/09/01, 22:31:42

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