实时系统

目录

任务一

  • 学习使用Linux命令wc(1)

  • 基于Linux Socket程序设计实现wc(1)服务器和客户端

    • 客户端传一个文本文件给服务器
    • 服务器返加文本文件中的单词数
wc命令
  1. 格式wc [选项]文件...
  2. 功能:统计指定文件中的字节数、字数、行数,并将统计结果显示输出。该命令统计指定文件中的字节数、字数、行数。如果没有给出文件名,则从标准输入读取。wc同时也给出所指定文件的总统计数。
  3. 参数
  • -c 统计字节数
  • -l 统计行数
  • -m 统计字符数(这个标志不能与-c标志一起使用)
  • -w 统计字数。一个字被定义为由空白、跳格或换行字符分隔的字符串
  • -L 打印最长行的长度
  • -help 显示帮助信息
  • --version 显示版本信息
代码实现

服务器

#include<netinet/in.h>  // sockaddr_in  
#include<sys/types.h>   // socket  
#include<sys/socket.h>  // socket  
#include<stdio.h>       // printf  
#include<stdlib.h>      // exit  
#include<string.h>      // bzero  
  
#define SERVER_PORT 165326  
#define LENGTH_OF_LISTEN_QUEUE 20  
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512  
 
int main(void)  
{  
    // 声明并初始化一个服务器端的socket地址结构  
    struct sockaddr_in server_addr;  
    bzero(&server_addr, sizeof(server_addr));  
    server_addr.sin_family = AF_INET;  
    server_addr.sin_addr.s_addr = htons(INADDR_ANY);  
    server_addr.sin_port = htons(SERVER_PORT);  
  
    // 创建socket,若成功,返回socket描述符  
    int server_socket_fd = socket(PF_INET, SOCK_STREAM, 0);  
    if(server_socket_fd < 0)  
    {  
        perror("Create Socket Failed:");  
        exit(1);  
    }  
    int opt = 1;  
    setsockopt(server_socket_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));  
  
    // 绑定socket和socket地址结构  
    if(-1 == (bind(server_socket_fd, (struct sockaddr*)&server_addr, sizeof(server_addr))))  
    {  
        perror("Server Bind Failed:");  
        exit(1);  
    }  
      
    // socket监听  
    if(-1 == (listen(server_socket_fd, LENGTH_OF_LISTEN_QUEUE)))  
    {  
        perror("Server Listen Failed:");  
        exit(1);  
    }  
  
    while(1)  
    {  
        // 定义客户端的socket地址结构  
        struct sockaddr_in client_addr;  
        socklen_t client_addr_length = sizeof(client_addr);  
  
        // 接受连接请求,返回一个新的socket(描述符),这个新socket用于同连接的客户端通信  
        // accept函数会把连接到的客户端信息写到client_addr中  
        int new_server_socket_fd = accept(server_socket_fd, (struct sockaddr*)&client_addr, &client_addr_length);  
        if(new_server_socket_fd < 0)  
        {  
            perror("Server Accept Failed:");  
            break;  
        }  
  
       // recv函数接收数据到缓冲区buffer中  
        char buffer[BUFFER_SIZE];  
        bzero(buffer, BUFFER_SIZE);  
        if(recv(new_server_socket_fd, buffer, BUFFER_SIZE, 0) < 0)  
        {  
            perror("Server Recieve Data Failed:");  
            break;  
        }  
  
        // 然后从buffer(缓冲区)拷贝到file_name中  
        char file_name[FILE_NAME_MAX_SIZE+1];  
        bzero(file_name, FILE_NAME_MAX_SIZE+1);  
        strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE?FILE_NAME_MAX_SIZE:strlen(buffer));  
        printf("%s\n", file_name);  
  
	// 打开文件,准备写入  
    	FILE *fp = fopen(file_name, "w");  
    	if(NULL == fp)  
    	{  
        	printf("File:\t%s Can Not Open To Write\n", file_name);  
        	exit(1);  
    	}  
  	
	// 从客户端接收数据到buffer中  
    	// 每接收一段数据,便将其写入文件中,循环直到文件接收完并写完为止  
    	bzero(buffer, BUFFER_SIZE);  
    	int length = 0;  
    	while((length = recv(new_server_socket_fd, buffer, BUFFER_SIZE, 0)) > 0)  
    	{  
		if(strcmp(buffer,"OK")==0) break;
        	if(fwrite(buffer, sizeof(char), length, fp) < length)  
        	{  
            	printf("File:\t%s Write Failed\n", file_name);  
            	break;  
        	}  
        	bzero(buffer, BUFFER_SIZE);  
    	}  
	
	
	// 接收成功后,关闭文件,关闭socket  
    	printf("Receive File:\t%s From Client IP Successful!\n", file_name);  
    	fclose(fp);


	// 统计文件单词个数,并发送给客户端
	int words=0;
	char s[100];
	FILE *fp2;
	if((fp2=fopen(file_name,"r"))==NULL){
		printf("ERROR!\n");
		exit(0);
	}
	while(fscanf(fp2,"%s",s)!=EOF)
		words++;
	fclose(fp2);
	//printf("%d words.\n",words);


	sprintf(buffer,"%d",words);

	send(new_server_socket_fd,buffer,BUFFER_SIZE,0);

	//send(new_server_socket_fd,&words,sizeof(words),0);
	close(new_server_socket_fd);  
	
	
	
        // 关闭与客户端的连接  
        
    }  
    // 关闭监听用的socket  
    close(server_socket_fd);  
    return 0;  
} 

客户端

#include<netinet/in.h>   // sockaddr_in  
#include<sys/types.h>    // socket  
#include<sys/socket.h>   // socket  
#include<stdio.h>        // printf  
#include<stdlib.h>       // exit  
#include<string.h>       // bzero  
  
#define SERVER_PORT 165326  
#define BUFFER_SIZE 1024  
#define FILE_NAME_MAX_SIZE 512  
  
int main()  
{  
    // 声明并初始化一个客户端的socket地址结构  
    struct sockaddr_in client_addr;  
    bzero(&client_addr, sizeof(client_addr));  
    client_addr.sin_family = AF_INET;  
    client_addr.sin_addr.s_addr = htons(INADDR_ANY);  
    client_addr.sin_port = htons(0);  
  
    // 创建socket,若成功,返回socket描述符  
    int client_socket_fd = socket(AF_INET, SOCK_STREAM, 0);  
    if(client_socket_fd < 0)  
    {  
        perror("Create Socket Failed:");  
        exit(1);  
    }  
  
    // 绑定客户端的socket和客户端的socket地址结构 非必需  
    if(-1 == (bind(client_socket_fd, (struct sockaddr*)&client_addr, sizeof(client_addr))))  
    {  
        perror("Client Bind Failed:");  
        exit(1);  
    }  
  
    // 声明一个服务器端的socket地址结构,并用服务器那边的IP地址及端口对其进行初始化,用于后面的连接  
    struct sockaddr_in server_addr;  
    bzero(&server_addr, sizeof(server_addr));  
    server_addr.sin_family = AF_INET;  
    if(inet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr) == 0)  
    {  
        perror("Server IP Address Error:");  
        exit(1);  
    }  
    server_addr.sin_port = htons(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_fd代表了客户端和服务器的一个socket连接  
    if(connect(client_socket_fd, (struct sockaddr*)&server_addr, server_addr_length) < 0)  
    {  
        perror("Can Not Connect To Server IP:");  
        exit(0);  
    }  
  
    // 输入文件名,并放到缓冲区buffer中等待发送  
    char file_name[FILE_NAME_MAX_SIZE+1];  
    bzero(file_name, FILE_NAME_MAX_SIZE+1);  

    printf("Please Input File Name On Client:\t");
    scanf("%s", file_name);  
  
    char buffer[BUFFER_SIZE];  
    bzero(buffer, BUFFER_SIZE);  
    strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE?BUFFER_SIZE:strlen(file_name));  
      
    // 向服务器发送buffer中的数据  
    if(send(client_socket_fd, buffer, BUFFER_SIZE, 0) < 0)  
    {  
        perror("Send File Name Failed:");  
        exit(1);  
    }  
  
    
    // 打开文件并读取文件数据  
        FILE *fp = fopen(file_name, "r");  
        if(NULL == fp)  
        {  
            printf("File:%s Not Found\n", file_name);  
        }  
        else  
        {  
            bzero(buffer, BUFFER_SIZE);  
            int length = 0;  
            // 每读取一段数据,便将其发送给服务器,循环直到文件读完为止  
            while((length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0)  
            {  
                if(send(client_socket_fd, buffer, length, 0) < 0)  
                {  
                    printf("Send File:%s Failed./n", file_name);  
                    break;  
                }  
                bzero(buffer, BUFFER_SIZE);  
            }  
  
            // 关闭文件  
	    
            fclose(fp);  
            printf("File:%s Transfer Successful!\n", file_name);  
	    char s[50];	
	    scanf("%s",s);
	    send(client_socket_fd,"OK",BUFFER_SIZE,0);
	    recv(client_socket_fd,buffer,BUFFER_SIZE,0);	
	    printf("%d words.\n",atoi(buffer));
	}  

    close(client_socket_fd);  
    return 0;  
} 

实验截图

  • wc指令执行
  • 服务器客户端连接传输

任务二

使用多线程实现wc服务器并使用同步互斥机制保证计数正确

  • 只需要改变任务一服务器代码即可。
    • 增加多线程
    • 使用同步互斥
代码实现

服务器

#include <stdio.h>
#include <fcntl.h>
#include <pthread.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#define PORT 165326
#define BUFF_SIZE 1024

typedef struct{
    char type;
    char data[BUFF_SIZE];
}m_package;

void* process_client();

int main(){
    int ss = create_tcp_server(PORT);
    if(-1 == ss)
        exit(-1);
    while(1){
        //接受客户端连接
        socklen_t addrlen = sizeof(struct sockaddr);
        struct sockaddr_in client_addr; //客户端地址结构
        int client_sock = accept(ss, (struct sockaddr*)&client_addr, &addrlen);
        if(client_sock < 0){
            printf("accept error\n");
        }
        printf("accept success\n");

        pthread_t pid;
        if(pthread_create(&pid, NULL, process_client, &client_sock) < 0){
            printf("pthread_create error\n");
        }
    }
}

//处理客户端程序
void *process_client(void *arg){
    int size = 0, fd, count = 0, sockid = *(int*)arg;
    m_package pac;
    long total = 0, cur = 0;
    //循环接收文件
    while(1) {
        memset(&pac, 0, sizeof(pac));
        size = read(sockid, &pac, sizeof(pac));
        if(size > 0){
            if (pac.type == 1){
                fd = open(pac.data, O_CREAT|O_WRONLY, 0777);
                if(-1 == fd){
                    printf("open file error!\n");
                    continue;
                }
                count = total = cur = 0;
            }
            else if (pac.type == 2){
                cur += write(fd, pac.data, strlen(pac.data));
                if(count++ % 5000 == 0){
                    printf("recv from client < %d > : %.01lf\%\n", sockid, cur * 100.0 / total);
                    count = 0;
                }
            }
            else if (pac.type == 3){
                printf("recv from client < %d > : 100.0\%\n", sockid);
                printf("recv success\n");
                close(fd);
            }
            else if(pac.type == 4){//文件长度
                total = strtol(pac.data, NULL, 10);
                printf("%ld\n", total);
            }
        }else{
            printf("client disconnected\n");
            close(sockid);
            break;
        }
    }
    return 0;
}
实验截图

遇到的问题

bind:Address already in use

  • Ctrl+C强制结束进程
  • 给套接字应用 SO_REUSEADDR 套接字选项,以便端口可以马上重用
  • 使用linux% netstat -tanlplinux% kill (pid)指令切断有此端口号的进程。

参考资料

bind出现Address already in use解决方法
进程同步互斥机制