2018-2019-1 20165229 20165306 实验三 实时系统

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2018-2019-1 20165229 20165306 实验三 实时系统

实验三-并发程序-1

  • 学习使用Linux命令wc(1)。

技术分享图片

-c 统计字节数

-m 统计字符数,这个标志不能与 -c 标志一起使用

-l 统计行数

-L 打印最长行的长度

-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

技术分享图片

  • 基于Linux Socket程序设计实现wc(1)服务器(端口号是你学号的后6位)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。

技术分享图片

技术分享图片

  • server.c
#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
#include<unistd.h>
#define SERVER_PORT 155316
#define LENGTH_OF_LISTEN_QUEUE 20
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512
int CountWordsOfEuropeanTxtFile(char *szFileName);
int CountWordsInOneLine(const char *szLine);
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("5316:%s
", file_name);
    int count=0;
    bzero(buffer, BUFFER_SIZE);
    count = CountWordsOfEuropeanTxtFile(file_name);
    sprintf(buffer,"%d", count);
        if(send(new_server_socket_fd, buffer, sizeof(buffer), 0) < 0)
        {
               printf("Send File:%s Failed./n", file_name);
        }
    bzero(buffer, BUFFER_SIZE); 
        /*/ 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
", file_name);
        }
        else
        {
            bzero(buffer, BUFFER_SIZE);
            int length = 0;
            / 每读取一段数据,便将其发送给客户端,循环直到文件读完为止
            while((length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0)
            {
                if(send(new_server_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!
", file_name);
        }*/
        // 关闭与客户端的连接
        close(new_server_socket_fd);
    }
    // 关闭监听用的socket
    close(server_socket_fd);
    return 0;
}
int CountWordsOfEuropeanTxtFile(char *szFileName)
{
    int nWords = 0;//词计数变量,初始值为0
    FILE *fp; //文件指针
    char carrBuffer[1024];//每行字符缓冲,每行最多1024个字符
    //打开文件
    if ((fp = fopen(szFileName,  "r")) == NULL)
    {
        return -1;  //文件打开不成功是返回-1
    }
    while (!feof(fp))//如果没有读到文件末尾 
    {
        //从文件中读一行
        if (fgets(carrBuffer, sizeof(carrBuffer),fp) != NULL)
            //统计每行词数
            nWords += CountWordsInOneLine(carrBuffer);
    }
    //关闭文件
    fclose(fp);
    return nWords;
}
int CountWordsInOneLine(const char *szLine)
{
    int nWords = 0;
    int i=0;
    for (;i<strlen(szLine);i++)
    {
        if (*(szLine+i)!=‘ ‘)
        {
            nWords++;
            while ((*(szLine+i)!=‘ ‘)&&(*(szLine+i)!=‘‘))
            {
                i++;
            }
        }

    }
            //printf("%d	",nWords);
    
    return nWords;
}
  • client.c
#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
#include<unistd.h>
#include<stdlib.h>
#define SERVER_PORT 155316
#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 Server:	");
    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);
    }   
    //int count=0;
    int length=0;
    bzero(buffer, BUFFER_SIZE);
    length = recv(client_socket_fd, buffer, BUFFER_SIZE, 0);
    buffer[length] = ‘‘;
    printf("count=%s
", buffer);
    bzero(buffer, BUFFER_SIZE);   
    /* / 打开文件,准备写入
     / FILE *fp = fopen(file_name, "w");
    if(NULL == fp)
    {
        printf("File:	%s Can Not Open To Write
", file_name);
        exit(1);
    }
    / 从服务器接收数据到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(client_socket_fd, buffer, BUFFER_SIZE, 0)) > 0)
    {
        if(fwrite(buffer, sizeof(char), length, fp) < length)
        {
            printf("File:	%s Write Failed
", file_name);
            break;
        }
        bzero(buffer, BUFFER_SIZE);
    }
    / 接收成功后,关闭文件,关闭socket
    printf("Receive File:	%s From Server IP Successful!
", file_name);
    fclose(fp);
    */
    close(client_socket_fd);
    return 0;
}

实验三-并发程序-2

  • 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

技术分享图片

技术分享图片

  • 对比单线程版本的性能,并分析原因

线程本身由于创建和切换的开销,采用多线程不会提高程序的执行速度,反而会降低速度,但是对于频繁IO操作的程序,多线程可以有效的并发。对于包含不同任务的程序,可以考虑每个任务使用一个线程。这样的程序在设计上相对于单线程做所有事的程序来说,更为清晰明了,比如生产、消费者问题。在实际的开发中对于性能优化的问题需要考虑到具体的场景来考虑是否使用多线程技术。

  • 遇到的问题

技术分享图片

解决:虽然程序包含了线程的头文件 <pthread.h> ,但是由于pthread库不是Linux系统默认的库,连接时需要使用库libpthread.a,所以在使用pthread_create创建线程时,在编译中要加 -lpthread 参数。即 gcc server2.c -lpthread -o server2

  • server2.c
#include<stdlib.h>
#include<pthread.h>
#include<sys/socket.h>
#include<sys/types.h>       //pthread_t , pthread_attr_t and so on.
#include<stdio.h>
#include<netinet/in.h>      //structure sockaddr_in
#include<arpa/inet.h>       //Func : htonl; htons; ntohl; ntohs
#include<assert.h>          //Func :assert
#include<string.h>          //Func :memset bzero
#include<unistd.h>          //Func :close,write,read
#define SOCK_PORT 9988
#define BUFFER_LENGTH 1024
#define MAX_CONN_LIMIT 512     //MAX connection limit
static void Data_handle(void * sock_fd);   //Only can be seen in the file
int CountWordsOfEuropeanTxtFile(char *szFileName);
int CountWordsInOneLine(const char *szLine);
int main()
{
    int sockfd_server;
    int sockfd;
    int fd_temp;
    struct sockaddr_in s_addr_in;
    struct sockaddr_in s_addr_client;
    int client_length;
    sockfd_server = socket(AF_INET,SOCK_STREAM,0);  //ipv4,TCP
    assert(sockfd_server != -1);
    //before bind(), set the attr of structure sockaddr.
    memset(&s_addr_in,0,sizeof(s_addr_in));
    s_addr_in.sin_family = AF_INET;
    s_addr_in.sin_addr.s_addr = htonl(INADDR_ANY);  //trans addr from uint32_t host byte order to network byte order.
    s_addr_in.sin_port = htons(SOCK_PORT);          //trans port from uint16_t host byte order to network byte order.
    fd_temp = bind(sockfd_server,(const struct sockaddr *)(&s_addr_in),sizeof(s_addr_in));
    if(fd_temp == -1)
    {
        fprintf(stderr,"bind error!
");
        exit(1);
    }
    fd_temp = listen(sockfd_server,MAX_CONN_LIMIT);
    if(fd_temp == -1)
    {
        fprintf(stderr,"listen error!
");
        exit(1);
    }
    while(1)
    {
        printf("waiting for new connection...
");
        pthread_t thread_id;
        client_length = sizeof(s_addr_client);
        //Block here. Until server accpets a new connection.
        sockfd = accept(sockfd_server,(struct sockaddr * restrict)(&s_addr_client),(socklen_t *)(&client_length));
        if(sockfd == -1)
        {
            fprintf(stderr,"Accept error!
");
            continue;                               //ignore current socket ,continue while loop.
        }
        printf("A new connection occurs!
");
        if(pthread_create(&thread_id,NULL,(void *)(&Data_handle),(void *)(&sockfd)) == -1)
        {
            fprintf(stderr,"pthread_create error!
");
            break;                                  //break while loop
        }
    }
    //Clear
    int ret = shutdown(sockfd_server,SHUT_WR); //shut down the all or part of a full-duplex connection.
    assert(ret != -1);
    printf("Server shuts down
");
    return 0;
}
static void Data_handle(void * sock_fd)
{
    int fd = *((int *)sock_fd);
    int i_recvBytes;
    char data_recv[BUFFER_LENGTH];
    const char * data_send = "Server has received your request!
";
    while(1)
    {
        printf("waiting for file_name...
");
        //Reset data.
        memset(data_recv,0,BUFFER_LENGTH);
        i_recvBytes = read(fd,data_recv,BUFFER_LENGTH);
        if(i_recvBytes == 0)
        {
            printf("Maybe the client has closed
");
            break;
        }
        if(i_recvBytes == -1)
        {
            fprintf(stderr,"read error!
");
            break;
        }
        if(strcmp(data_recv,"quit")==0)
        {
            printf("Quit command!
");
            break;                           //Break the while loop.
        }
        printf("read from client : %s
",data_recv);
        
    char buffer[BUFFER_LENGTH];
    int count=0;
    bzero(buffer, BUFFER_LENGTH);
    count = CountWordsOfEuropeanTxtFile(data_recv);
    sprintf(buffer,"%d", count);
        send(fd, buffer, sizeof(buffer), 0);
        if(write(fd,data_send,strlen(data_send)) == -1)
        {
            break;
        }
    }
    //Clear
    printf("terminating current client_connection...
");
    close(fd);            //close a file descriptor.
    pthread_exit(NULL);   //terminate calling thread!
}
int CountWordsOfEuropeanTxtFile(char *szFileName)
{
    int nWords = 0;//词计数变量,初始值为0
    FILE *fp; //文件指针
    char carrBuffer[1024];//每行字符缓冲,每行最多1024个字符
    //打开文件
    if ((fp = fopen(szFileName,  "r")) == NULL)
    {
        return -1;  //文件打开不成功是返回-1
    }
    while (!feof(fp))//如果没有读到文件末尾 
    {
        //从文件中读一行
        if (fgets(carrBuffer, sizeof(carrBuffer),fp) != NULL)
            //统计每行词数
            nWords += CountWordsInOneLine(carrBuffer);
    }

    //关闭文件
    fclose(fp);
    return nWords;
}
int CountWordsInOneLine(const char *szLine)
{
    int nWords = 0;
    int i=0;
    for (;i<strlen(szLine);i++)
    {
        if (*(szLine+i)!=‘ ‘)
        {
            nWords++;
            while ((*(szLine+i)!=‘ ‘)&&(*(szLine+i)!=‘‘))
            {
                i++;
            }
        }

    }
            //printf("%d	",nWords);
    
    return nWords;
}
  • client2.c
#include<stdlib.h>
#include<sys/socket.h>
#include<sys/types.h>       //pthread_t , pthread_attr_t and so on.
#include<stdio.h>
#include<netinet/in.h>      //structure sockaddr_in
#include<arpa/inet.h>       //Func : htonl; htons; ntohl; ntohs
#include<assert.h>          //Func :assert
#include<string.h>          //Func :memset bzero
#include<unistd.h>          //Func :close,write,read
#define SOCK_PORT 9988
#define BUFFER_LENGTH 1024
int main()
{
    int sockfd;
    int tempfd;
    struct sockaddr_in s_addr_in;
    char data_send[BUFFER_LENGTH];
    char data_recv[BUFFER_LENGTH];
    memset(data_send,0,BUFFER_LENGTH);
    memset(data_recv,0,BUFFER_LENGTH);
    sockfd = socket(AF_INET,SOCK_STREAM,0);       //ipv4,TCP
    if(sockfd == -1)
    {
        fprintf(stderr,"socket error!
");
        exit(1);
    }
    //before func connect, set the attr of structure sockaddr.
    memset(&s_addr_in,0,sizeof(s_addr_in));
    s_addr_in.sin_addr.s_addr = inet_addr("127.0.0.1");      //trans char * to in_addr_t
    s_addr_in.sin_family = AF_INET;
    s_addr_in.sin_port = htons(SOCK_PORT);
    tempfd = connect(sockfd,(struct sockaddr *)(&s_addr_in),sizeof(s_addr_in));
    if(tempfd == -1)
    {
        fprintf(stderr,"Connect error! 
");
        exit(1);
    }
    while(1)
    {
        printf("Please Input File Name On Server(input "quit" to quit):	");
    scanf("%s", data_send);        
    //gets(data_send);
        //scanf("%[^
]",data_send);         //or you can also use this
        tempfd = write(sockfd,data_send,BUFFER_LENGTH);
        if(tempfd == -1)
        {
            fprintf(stderr,"write error
");
            exit(0);
        }

        if(strcmp(data_send,"quit") == 0)  //quit,write the quit request and shutdown client
        {
            break;
        }
        else
        {
            tempfd = read(sockfd,data_recv,BUFFER_LENGTH);
            assert(tempfd != -1);
            printf("%s
",data_recv);
            memset(data_send,0,BUFFER_LENGTH);
            memset(data_recv,0,BUFFER_LENGTH);
        }
    char buffer[BUFFER_LENGTH];
    int length=0;
    bzero(buffer, BUFFER_LENGTH);
        length = recv(sockfd, buffer, BUFFER_LENGTH, 0);
        buffer[length] = ‘‘;
        printf("count=%s
", buffer);
        bzero(buffer, BUFFER_LENGTH);
    }
    int ret = shutdown(sockfd,SHUT_WR);       //or you can use func close()--<unistd.h> to close the fd
    assert(ret != -1);
    return 0;
}

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