~/arch/x86/entry/syscalls/syscall_64.tbl

#include <sys/socket.h>
int listen(int sockfd, int backlog)

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
int main()
{
	int sockfd,new_fd,listen_result;
	struct sockaddr_in my_addr;
	struct sockaddr_in their_addr;
	int sin_size;
	//建立TCP套接口
	if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1)
	{
		printf("create socket error");
		perror("socket");
		exit(1);
	}
	//初始化結構體，並綁定2323端口
	my_addr.sin_family = AF_INET;
	my_addr.sin_port = htons(2328);
	my_addr.sin_addr.s_addr = INADDR_ANY;
	bzero(&(my_addr.sin_zero),8);
	//綁定套接口
	if(bind(sockfd,(struct sockaddr *)&my_addr,sizeof(struct sockaddr))==-1)
	{
		perror("bind socket error");
		exit(1);
	}
	//創建監聽套接口, 監聽隊列長度為10
        //listen_result = listen(sockfd,10);
        asm volatile(
            "movl $0xa,%%edi\n\t"    //listen函數的第二個參數
            "movl %1,%%edi\n\t"      //listen函數的第一個參數
            "movl $0x32,%%eax\n\t"   //將系統調用號50存入eax寄存器
            "syscall\n\t"
            "movq %%rax,%0\n\t"
            :"=m"(listen_result)
            :"g"(sockfd)
        );
        if(listen_result == 0)
        {
            printf("listen is being called\n");
        }
	if(listen_result ==-1)
	{
		perror("listen");
		exit(1);
	}

	//等待連接
	while(1)
	{
		sin_size = sizeof(struct sockaddr_in);

		printf("server is run.\n");
		//如果建立連接，將產生一個全新的套接字
		if((new_fd = accept(sockfd,(struct sockaddr *)&their_addr,&sin_size))==-1)
		{
			perror("accept");
			exit(1);
		}
		printf("accept success.\n");
		//生成一個子進程來完成和客戶端的會話，父進程繼續監聽
		if(!fork())
		{
			printf("create new thred success.\n");
			//讀取客戶端發來的信息
			int numbytes;
			char buff[256];
			memset(buff,0,256);
			if((numbytes = recv(new_fd,buff,sizeof(buff),0))==-1)
			{
			perror("recv");
			exit(1);
			}
			printf("%s",buff);
			//將從客戶端接收到的信息再發回客戶端
			if(send(new_fd,buff,strlen(buff),0)==-1)
				perror("send");
			close(new_fd);
			exit(0);
		}
		close(new_fd);
	}
	close(sockfd);
}

        asm volatile(
            "movl $0xa,%%edi\n\t"    //listen函數的第二個參數
            "movl %1,%%edi\n\t"      //listen函數的第一個參數
            "movl $0x32,%%eax\n\t"   //將系統調用號50存入eax寄存器
            "syscall\n\t"
            "movq %%rax,%0\n\t"
            :"=m"(listen_result)
            :"g"(sockfd)
        );

        listen_result = listen(sockfd,10);

#include <stdio.h>
#include <stdlib.h>

#include <string.h>
#include <netdb.h>
#include <sys/types.h>

#include <sys/socket.h>

int main(int argc,char *argv[])
{

	int sockfd,numbytes;
 	char buf[100];

	struct sockaddr_in their_addr;

	//建立一個TCP套接口
	if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1)
	{
		perror("socket");
		printf("create socket error.建立一個TCP套接口失敗");
		exit(1);
	}
	//初始化結構體，連接到服務器的2323端口
	their_addr.sin_family = AF_INET;
	their_addr.sin_port = htons(2328);
	// their_addr.sin_addr = *((struct in_addr *)he->h_addr);
	inet_aton( "127.0.0.1", &their_addr.sin_addr );


	bzero(&(their_addr.sin_zero),8);
	//和服務器建立連接
	if(connect(sockfd,(struct sockaddr *)&their_addr,sizeof(struct sockaddr))==-1)
	{
		perror("connect");
		exit(1);
	}
	//向服務器發送數據
	if(send(sockfd,"hello!socket.",6,0)==-1)
	{
		perror("send");
		exit(1);
	}
	//接受從服務器返回的信息
	if((numbytes = recv(sockfd,buf,100,0))==-1)
	{
		perror("recv");
		exit(1);
	}
	buf[numbytes] = '/0';
	printf("Recive from server:%s",buf);
	//關閉socket
	close(sockfd);

	return 0;
}

gcc -o server server.c -static
gcc -o client client.c  -static

sudo  ./server

sudo ./client

sudo apt install build-essential
sudo apt install qemu # install QEMU
sudo apt install libncurses5-dev bison flex libssl-dev libelf-dev
sudo apt install axel

axel -n 20 //mirrors.edge.kernel.org/pub/linux/kernel/v5.x/linux-5.4.34.tar.xz
xz -d linux-5.4.34.tar.xz
tar -xvf linux-5.4.34.tar
cd linux-5.4.34

make defconfig # Default configuration is based on 'x86_64_defconfig'
make menuconfig
# 打開debug相關選項
Kernel hacking --->
    Compile-time checks and compiler options --->
        [*] Compile the kernel with debug info
        [*] Provide GDB scripts for kernel debugging
    [*] Kernel debugging
# 關閉KASLR，否則會導致打斷點失敗
Processor type and features ---->
    [] Randomize the address of the kernel image (KASLR)

make -j$(nproc) # nproc gives the number of CPU cores/threads available

#測試⼀下內核能不能正常加載運⾏，因為沒有⽂件系統最終會kernel panic

qemu-system-x86_64 -kernel arch/x86/boot/bzImage

axel -n 20 //busybox.net/downloads/busybox-1.31.1.tar.bz2
tar -jxvf busybox-1.31.1.tar.bz2
cd busybox-1.31.1

make menuconfig
#記得要編譯成靜態鏈接，不⽤動態鏈接庫。
Settings --->
    [*] Build static binary (no shared libs)
#然後編譯安裝，默認會安裝到源碼⽬錄下的 _install ⽬錄中。
make -j$(nproc) && make install

mkdir rootfs
cd rootfs
cp ../busybox-1.31.1/_install/* ./ -rf
mkdir dev proc sys home
sudo cp -a /dev/{null,console,tty,tty1,tty2,tty3,tty4} dev/

#!/bin/sh
mount -t proc none /proc
mount -t sysfs none /sys
echo "Wellcome Liu JianingOS!"
echo "--------------------"
cd home
/bin/sh

chmod +x init

find . -print0 | cpio --null -ov --format=newc | gzip -9 > ../rootfs.cpio.gz

qemu-system-x86_64 -kernel arch/x86/boot/bzImage -initrd rootfs.cpio.gz

gcc -o server server.c -static
gcc -o client client.c -static

find . -print0 | cpio --null -ov --format=newc | gzip -9 > ../rootfs.cpio.gz

qemu-system-x86_64 -kernel arch/x86/boot/bzImage -initrd rootfs.cpio.gz -S -s -nographic -append "console=ttyS0"

gdb vmlinux

(gdb) target remote:1234

(gdb) b 系統調用函數名

(gdb) b __x64_sys_listen

(gdb) n