2017-2018-1 20155211 《信息安全系统设计基础》第八周学习总结

2017-2018-1 20155211 《信息安全系统设计基础》第八周学习总结

课下测试一

1 完成家庭作业4.47，4.48，4.49

2 相应代码反汇编成X86-64汇编

3 把上述X86-64汇编翻译成Y86汇编，并给出相应机器码

• 4.47
  

• 4.48
  

• 4.49
  

• 遇到的问题：x86翻译成y86汇编时，运用虚拟机时一直报错，后用在线模拟器时出现了不同的报错。。经查询尚未解决。
  

课下测试二

把课上练习3的daytime服务器分别用多进程和多线程实现成并发服务器并测试

• 代码如下
  • client1.c

#include <netinet/in.h>    // for sockaddr_in
#include <sys/types.h>    // for socket
#include <sys/socket.h>    // for socket
#include <stdio.h>        // for printf
#include <stdlib.h>        // for exit
#include <string.h>        // for bzero
#include <time.h>
#define HELLO_WORLD_SERVER_PORT    6666 
#define BUFFER_SIZE 1024
void talk_to_server(char ** argv)
{
    //设置一个socket地址结构client_addr,代表客户机internet地址, 端口
    struct sockaddr_in client_addr;
    bzero(&client_addr,sizeof(client_addr)); //把一段内存区的内容全部设置为0
    client_addr.sin_family = AF_INET;    //internet协议族
    client_addr.sin_addr.s_addr = htons(INADDR_ANY);//INADDR_ANY表示自动获取本机地址
    client_addr.sin_port = htons(0);    //0表示让系统自动分配一个空闲端口
    //创建用于internet的流协议(TCP)socket,用client_socket代表客户机socket
    int client_socket = socket(AF_INET,SOCK_STREAM,0);
    time_t t;
    if( client_socket < 0)
    {
        printf("Create Socket Failed!
");
        exit(1);
    }
    //把客户机的socket和客户机的socket地址结构联系起来
    if( bind(client_socket,(struct sockaddr*)&client_addr,sizeof(client_addr)))
    {
        printf("Client Bind Port Failed!
"); 
        exit(1);
    }//设置一个socket地址结构server_addr,代表服务器的internet地址, 端口
    struct sockaddr_in server_addr;
    bzero(&server_addr,sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    if(inet_aton(argv[1],&server_addr.sin_addr) == 0) //服务器的IP地址来自程序的参数
    {
        printf("Server IP Address Error!
");
        exit(1);
    }
    server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
    socklen_t server_addr_length = sizeof(server_addr);
    //向服务器发起连接,连接成功后client_socket代表了客户机和服务器的一个socket连接
    if(connect(client_socket,(struct sockaddr*)&server_addr, server_addr_length) < 0)
    {
        printf("Can Not Connect To %s!
",argv[1]);
        exit(1);
    }

    char buffer[BUFFER_SIZE];
    bzero(buffer,BUFFER_SIZE);
    //从服务器接收数据到buffer中
    int length = recv(client_socket,buffer,BUFFER_SIZE,0);
    if(length < 0)
    {
        printf("Recieve Data From Server %s Failed!
", argv[1]);
        exit(1);
    }
    printf("From Server %s :	%s
",argv[1],buffer);
    length = recv(client_socket,(void *)&t,sizeof(time_t),0);
    if(length < 0)
    {
        printf("Recieve Data From Server %s Failed!
", argv[1]);
        exit(1);
    }
    printf("当前时间： %s 
",ctime(&t));
    bzero(buffer,BUFFER_SIZE);
    //strcpy(buffer,"Thanks!");
    //向服务器发送buffer中的数据
    send(client_socket,buffer,BUFFER_SIZE,0);
    //关闭socket
    close(client_socket);
}
int main(int argc, char **argv)
{
    if (argc != 2)
    {
        printf("Usage: .\%s ServerIPAddress
",argv[0]);
        exit(1);
    }
    talk_to_server(argv);

    return 0;
}

• server1.c

#include <netinet/in.h>    // for sockaddr_in
#include <sys/types.h>    // for socket
#include <sys/socket.h>    // for socket
#include <stdio.h>        // for printf
#include <stdlib.h>        // for exit
#include <string.h>        // for bzero
#include <unistd.h>        // for fork
#include <sys/signal.h> // for signal
#include <sys/wait.h>    // for wait
#include <time.h>
#include <arpa/inet.h>
#define HELLO_WORLD_SERVER_PORT    6666 
#define LENGTH_OF_LISTEN_QUEUE  20
#define BUFFER_SIZE 1024
void reaper(int sig)
{
    int status;
    //调用wait3读取子进程的返回值,使zombie状态的子进程彻底释放
    while(wait3(&status,WNOHANG,(struct rusage*)0) >=0)
        ;
}
int main(int argc, char **argv)
{
    //设置一个socket地址结构server_addr,代表服务器internet地址, 端口
    struct sockaddr_in server_addr;
    bzero(&server_addr,sizeof(server_addr)); //把一段内存区的内容全部设置为0
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htons(INADDR_ANY);
    server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
    time_t t;
//创建用于internet的流协议(TCP)socket,用server_socket代表服务器socket
    int server_socket = socket(AF_INET,SOCK_STREAM,0);
    if( server_socket < 0)
    {
        printf("Create Socket Failed!
");
        exit(1);
    }
    //把socket和socket地址结构联系起来
    if( bind(server_socket,(struct sockaddr*)&server_addr,sizeof(server_addr)))
    {
        printf("Server Bind Port : %d Failed!
", HELLO_WORLD_SERVER_PORT); 
        exit(1);
    }
    //server_socket用于监听
    if ( listen(server_socket, LENGTH_OF_LISTEN_QUEUE) )
    {
        printf("Server Listen Failed!"); 
        exit(1);
    }
    //通知操作系统,当收到子进程的退出信号(SIGCHLD)时,执行reaper函数,释放zombie状态的进程
    (void)signal(SIGCHLD,reaper);
    while (1) //服务器端要一直运行
    {
        //定义客户端的socket地址结构client_addr
        struct sockaddr_in client_addr;
        socklen_t length = sizeof(client_addr);
    //接受一个到server_socket代表的socket的一个连接
        //如果没有连接请求,就等待到有连接请求--这是accept函数的特性
        //accept函数返回一个新的socket,这个socket(new_server_socket)用于同连接到的客户的通信
        //new_server_socket代表了服务器和客户端之间的一个通信通道
        //accept函数把连接到的客户端信息填写到客户端的socket地址结构client_addr中
int new_server_socket = accept(server_socket,(struct sockaddr*)&client_addr,&length);
        if ( new_server_socket < 0)
        {
            printf("Server Accept Failed!
");
            break;
        }
        int child_process_pid = fork(); //fork()后,子进程是主进程的拷贝
        //在主进程和子进程中的区别是fork()的返回值不同.
        if(child_process_pid == 0 )//如果当前进程是子进程,就执行与客户端的交互
        {
             t=time(NULL);
            close(server_socket); //子进程中不需要被复制过来的server_socket
            char buffer[BUFFER_SIZE];
            bzero(buffer, BUFFER_SIZE);
              strcat(buffer,"
"); //C语言字符串连接              
          //发送buffer中的字符串到new_server_socket,实际是给客户端
            send(new_server_socket,buffer,BUFFER_SIZE,0);
            printf("服务器实现者学号：20155211
");
        printf("客户端IP：%s 
",inet_ntoa(client_addr.sin_addr));
            printf("当前时间： %s
",ctime(&t));
            send(new_server_socket,(void *)&t,sizeof(time_t),0);
    bzero(buffer,BUFFER_SIZE);
            //接收客户端发送来的信息到buffer中
            length = recv(new_server_socket,buffer,BUFFER_SIZE,0);
            if (length < 0)
            {
                printf("Server Recieve Data Failed!
");
                exit(1);
            }
            printf("
%s
",buffer);
            //关闭与客户端的连接
            close(new_server_socket); 
            exit(0);         
        }
        else if(child_process_pid > 0)     //如果当前进程是主进程 
            close(new_server_socket);    //主进程中不需要用于同客户端交互的new_server_socket
    }
    //关闭监听用的socket
    close(server_socket);
    return 0;
}

• 多线程

#include "csapp.h"
#include <time.h>
#include <string.h>
#define MAXRECVLEN 1024
void echo(int connfd)
{
    
    size_t n; 
    char buf[MAXLINE]; 
    rio_t rio;
    time_t ticks = time(NULL);

    Rio_readinitb(&rio, connfd);
    while((n = Rio_readlineb(&rio, buf, MAXLINE)) != 0) {
    /*printf("server received %d bytes
", n);*/
        printf("server received %d bytes
，%s",n,buf);
        printf("服务器实现人：20155211xxy
当前时间：%.24s
",ctime(&ticks));
        snprintf(buf,MAXRECVLEN,"当前时间：%.24s
",ctime(&ticks));
    Rio_writen(connfd, buf, n);
    }
    
}

void *thread(void *vargp);

int main(int argc, char **argv) 
{
    int listenfd, *connfdp, port, clientlen=sizeof(struct sockaddr_in);
    struct sockaddr_in clientaddr;
    pthread_t tid; 

    if (argc != 2) {
    fprintf(stderr, "usage: %s <port>
", argv[0]);
    exit(0);
    }
    port = atoi(argv[1]);

    listenfd = Open_listenfd(port);
    while (1) {
    connfdp = Malloc(sizeof(int));
    *connfdp = Accept(listenfd, (SA *) &clientaddr, &clientlen);
    pthread_create(&tid, NULL, thread, connfdp);
    }
}

/* thread routine */
void *thread(void *vargp) 
{  
    int connfd = *((int *)vargp);
    pthread_detach(pthread_self()); 
    Free(vargp);
    echo(connfd);
    Close(connfd);
    return NULL;
}

• 出现的问题
  编译成功后运行时出现如下问题
  尚未能解决
  

课上测试一

• 截图
  

课上测试三

• 问题如课下测试二