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在过去的 5 个小时里，我倾注了我的代码，但一无所获。每当我运行我的代码时，我都会遇到分段错误。有时它发生在客户端，有时发生在服务器端，所以我只是不确定发生了什么。 当我尝试查找最大为 100 的素数时，该代码有效，但之后就没有了。当我上次在这里发布时，我被告知要发布我的完整代码，所以这里是：

服务器：

void sieve(int *isComposite, int maximum, int maxSqrt) {

    int m = isComposite[0];
    int currentPrime = m-1;

    //Loop through "maxSqrt" times through the array
    if(m <= maxSqrt){
        //Loop through the multiples of the number we're
        //looking at (m) and mark them as composite (1)
        for (int k = currentPrime * currentPrime; k <= maximum; k += currentPrime){
            if(isComposite[k+1] == 0){
                //cout << "Removing: " << k << endl;
                isComposite[k+1] = 1;
            }
        }
    }
}

int main(int argc, char *argv[]){
    int sockfd, newsockfd, portno; // listen on sock_fd, new connection on new_fd, port number
    socklen_t clilen;

    struct sockaddr_in serv_addr, cli_addr;  // my address information, connector's address information
    int n;
    int open = 1; //true


    if (argc < 2) {
        fprintf(stderr,"ERROR, no port provided\n");
        exit(1);
    }

    //Socket setup
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        error("ERROR opening socket");
    } 
    bzero((char *) &serv_addr, sizeof(serv_addr));
    portno = atoi(argv[1]);             //port number (ex. 10.12.110.57 or thing-1.uwec.edu)
    serv_addr.sin_family = AF_INET;     // host byte order
    serv_addr.sin_port = htons(portno); // short, network byte order
    serv_addr.sin_addr.s_addr = INADDR_ANY;  // use my IP address

    //Bind socket
    if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
        error("ERROR on binding");
    }
    //Listen for connection
    listen(sockfd,5);

    //Accept the connection
    clilen = sizeof(cli_addr);
    newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
    if (newsockfd < 0){
        error("ERROR on accept");
    }
    printf("Connection accepted!\n");

    // Variable to college the largest number in the range
    int maximum;

    // Collect the maximum
    cout << "\nEnter a Maximum:";
    cin >> maximum;
    cout << "\n";

    int *maxToSend = new int[1];
    maxToSend[0] = maximum;

    if(send(newsockfd, maxToSend, 10, 0) < 0){
        perror("ERROR sending to socket");
    }


    int maxSqrt = (int)sqrt((double)maximum);

    // Declare the array to hold important 
    // information and the numbers to sieve
    int *isComposite= new int[maximum+1]();

    // Insert the variable that keeps track of where we
    // are in the array, starting with 2 (the first prime)
    // which is held in isComposite[3]
    isComposite[0] = 3;

    // Run the sieve for each prime we come accross
    // until we reach the prime that is the square
    // root of the maximum (isComposite[2])
    while(isComposite[0] <= maxSqrt){

        // Unless it is the first time through
        // Receive from the client
        if(isComposite[0] > 3){
            if(recv(newsockfd, isComposite, (maximum+1)* sizeof(int), 0) < 0){
                perror("ERROR receiving from socket");
            }
        }

        // If we're not done:
        if(isComposite[0] <= maxSqrt){
            // Sieve the range
            sieve(isComposite, maximum, maxSqrt);
            isComposite[0]++;

            // Find the next prime
            while(isComposite[isComposite[0]] == 1){
                isComposite[0]++;
            }
            cout << "Doing next Sieve on: " << isComposite[0]-1 << endl;

        }

        // If we're still not done:
        if(send(newsockfd, isComposite, (maximum+1)* sizeof(int), 0) < 0){
            if(send(newsockfd, isComposite, maximum+1500, 0) < 0){
                perror("ERROR sending to socket");
            }
        }
    }
    return 0;
}

客户：

void sieve(int *isComposite, int maximum, int maxSqrt) {

    int m = isComposite[0];
    int currentPrime = m-1;

    //Loop through "maxSqrt" times through the array
    if(m <= maxSqrt){
        //Loop through the multiples of the number we're
        //looking at (m) and mark them as composite (1)
        for (int k = currentPrime * currentPrime; k <= maximum; k += currentPrime){
            if(isComposite[k+1] == 0){
                //cout << "Removing: " << k << endl;
                isComposite[k+1] = 1;
            }
        }
    }
}

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

    int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;
    int open = 1; //true
    char c = 'a';

    if (argc < 3) {
       fprintf(stderr,"usage %s hostname port\n", argv[0]);
       exit(0);
    }

    portno = atoi(argv[2]);  //parse port number

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        error("ERROR opening socket");
    }

    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }

    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;   // host byte order
    bcopy((char *)server->h_addr,(char *)&serv_addr.sin_addr.s_addr, server->h_length);
    serv_addr.sin_port = htons(portno);  // short, network byte order


    if (connect(sockfd,(struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
        error("ERROR connecting");
    }

    int *maxToSend = new int[1];

    if(recv(sockfd, maxToSend, 10, 0) < 0){
        perror("ERROR receiving from socket");
    }

    int maximum = maxToSend[0];
    int maxSqrt = (int)sqrt((double)maximum);

    int *isComposite= new int[maximum+1]();

    while(isComposite[0] <= maxSqrt){

        if(recv(sockfd, isComposite, (maximum+1)* sizeof(int), 0) < 0){
            perror("ERROR receiving from socket");
        }

        // Sieve the range
        sieve(isComposite, maximum, maxSqrt);
        isComposite[0]++;

        // Find the next prime
        while(isComposite[isComposite[0]] == 1){
            isComposite[0]++;
        }
        cout << "Doing next Sieve on: " << isComposite[0]-1 << endl;

        if(send(sockfd, isComposite, (maximum+1)* sizeof(int), 0) < 0){
            perror("ERROR sending to socket");
        }

    }

    close(sockfd);
    return(0);
}
4

1 回答 1

3

原因是你的筛子越来越大，比一个包所能容纳的要大。您只能在一个数据包中存储大约 1400 个字节，而您的发送和接收功能不考虑这一点。您必须循环，直到您发送了您尝试发送的所有数据或读取您尝试读取的所有数据。看起来您尝试使用 执行此操作send(newsockfd, isComposite, maximum+1500, 0)，但您需要使用循环执行此操作，并跟踪您从 的返回值发送了多少数据send。

一个简单的函数可能看起来像

bool sendAll(int socket, const void *data, ssize_t size) {
    ssize_t sent = 0;
    ssize_t just_sent;
    while (sent < size) {
        just_sent = send(socket, data + sent, size - sent, 0);
        if (just_set < 0) {
            return false;
        }
        sent += just_sent;
    }
    return true;
}

和类似的东西recv。

于 2012-10-29T00:46:07.937 回答