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    MPS

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    sepal23274

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    © All Rights Reserved
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    MPS

    Uploaded by

    sepal23274
    12 views4 pages

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    © © All Rights Reserved

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    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    12 views4 pages

    MPS

    Uploaded by

    sepal23274

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
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    /*

    ** CSSE2310/CSSE7231 - Sample Server


    ** Accept connections on a given port, read text from connection
    ** turn it into upper case, send it back.
    ** Multi-process and multi-threaded versions of this server will
    ** be created in class.
    */
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netdb.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <ctype.h>
    #include <string.h>
    #include <sys/wait.h>
    #include <signal.h>

    // Listens on given port. Returns listening socket (or exits on failure)


    int open_listen(const char* port)
    {
    struct addrinfo* ai = 0;
    struct addrinfo hints;

    memset(&hints, 0, sizeof(struct addrinfo));


    hints.ai_family = AF_INET; // IPv4
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_PASSIVE; // listen on all IP addresses

    int err;
    if ((err = getaddrinfo(NULL, port, &hints, &ai))) {
    freeaddrinfo(ai);
    fprintf(stderr, "%s\n", gai_strerror(err));
    return 1; // Could not determine address
    }

    // Create a socket and bind it to a port


    int listenfd = socket(AF_INET, SOCK_STREAM, 0); // 0=default protocol (TCP)

    // Allow address (port number) to be reused immediately


    int optVal = 1;
    if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &optVal, sizeof(int))
    < 0) {
    perror("Error setting socket option");
    exit(1);
    }
    if (bind(listenfd, ai->ai_addr, sizeof(struct sockaddr)) < 0) {
    perror("Binding");
    return 3;
    }

    if (listen(listenfd, 10) < 0) { // Up to 10 connection requests can queue


    perror("Listen");
    return 4;
    }

    // Have listening socket - return it


    return listenfd;
    }

    // Function to capitalise a string (in place)


    char* capitalise(char* buffer, int len)
    {
    int i;

    for (i = 0; i < len; i++) {


    buffer[i] = (char)toupper((int)buffer[i]);
    }
    return buffer;
    }

    void process_connections(int fdServer)


    {
    int fd;
    struct sockaddr_in fromAddr;
    socklen_t fromAddrSize;
    char buffer[1024];
    ssize_t numBytesRead;

    // Repeatedly accept connections and process data (capitalise)


    while (1) {
    fromAddrSize = sizeof(struct sockaddr_in);
    // Block, waiting for a new connection. (fromAddr will be populated
    // with address of client)
    fd = accept(fdServer, (struct sockaddr*)&fromAddr, &fromAddrSize);
    if (fd < 0) {
    perror("Error accepting connection");
    exit(1);
    }

    // Turn our client address into a hostname and print out both
    // the address and hostname as well as the port number
    char hostname[NI_MAXHOST];
    int error = getnameinfo((struct sockaddr*)&fromAddr, fromAddrSize,
    hostname, NI_MAXHOST, NULL, 0, 0);
    if (error) {
    fprintf(stderr, "Error getting hostname: %s\n",
    gai_strerror(error));
    } else {
    printf("Accepted connection from %s (%s), port %d\n",
    inet_ntoa(fromAddr.sin_addr), hostname,
    ntohs(fromAddr.sin_port));
    }

    // Send a welcome message to our client


    dprintf(fd, "Welcome\n");
    //
    // Create child
    pid_t pid = fork();
    if (pid == 0) {
    // Child
    close(fdServer);
    dup2(fd, STDIN_FILENO);
    dup2(fd, STDOUT_FILENO);
    close(fd);
    execlp("tr", "tr", "a-z", "A-Z", NULL);
    // Should never get here
    exit(99);
    } else if (pid < 0) {
    perror("fork");
    exit(1);
    } else {
    // Parent
    close(fd);
    }
    }
    }

    void child_sig_handler(int sig)


    {
    pid_t pid;
    int status;

    while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {


    printf("Child done: %d\n", pid);
    fflush(stdout);
    }
    }

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


    {
    if (argc != 2) {
    fprintf(stderr, "Usage: %s port-num\n", argv[0]);
    exit(1);
    }

    int portnum = atoi(argv[1]);


    if (portnum < 1024 || portnum > 65535) {
    fprintf(stderr, "Invalid port number: %s\n", argv[1]);
    exit(1);
    }

    // Set up signal handler


    struct sigaction sa;
    sa.sa_handler = child_sig_handler;
    sa.sa_flags = SA_RESTART | SA_NOCLDSTOP;
    sigaction(SIGCHLD, &sa, NULL);

    const char* port = argv[1];


    int fdServer = open_listen(port);
    process_connections(fdServer);

    return 0;
    }

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