SPO1

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <string.h>
#include <argp.h>
#include <unistd.h>

int n_opt = 10;
char *ip_arg, i_opt;

struct argp_option options[] = {{NULL,      'i', "NUM", 0, "Transmission delay in seconds"},
                                {NULL, 'n', "NUM", 0, "Number of iterations"},
                                {0}};

static int parse_opt(int key, char *arg, struct argp_state *state) {
    int *arg_count = state->input;

    int tmp = arg ? strtol(arg, NULL, 10) : 0;
    if (tmp < 1 && (key == 'i' || key == 'n')) {
        fprintf(stderr, "error parsing option -%c", key);
        exit(EXIT_FAILURE);
    }

    switch (key) {
        case 'i':
            i_opt = tmp;
            break;
        case 'n':
            n_opt = tmp;
            break;
        case ARGP_KEY_ARG:
            if (*arg_count > 0)
                ip_arg = arg;
            (*arg_count)--;
            break;
        case ARGP_KEY_END:
            printf("\n");
            if (*arg_count > 0)
                argp_failure(state, 1, 0, "too few arguments");
            else if (*arg_count < 0)
                argp_failure(state, 1, 0, "too many arguments");
            break;
    }
    return 0;
}

int main(int argc, char **argv) {
    int sockfd, arg_count = 1;
    struct sockaddr_in serv_addr;
    char *srv_ip = NULL, *srv_port = NULL;

    struct argp argp = {options, parse_opt, "IP:PORT"};
    argp_parse(&argp, argc, argv, 0, 0, &arg_count);

    for (int i = 0, n = strlen(ip_arg); i < n; i++)
        if (ip_arg[i] == ':') {
            srv_ip = malloc(15 * sizeof(char));
            srv_port = malloc(5 * sizeof(char));
            strncpy(srv_ip, ip_arg, i);
            strncpy(srv_port, ip_arg + i + 1, n - i - 1);
            break;
        }

    if (!srv_ip || !srv_port) {
        fprintf(stderr, "failed to parse ip\n");
        exit(EXIT_FAILURE);
    }

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        fprintf(stderr, "socket failed\n");
        exit(EXIT_FAILURE);
    }

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = strtol(srv_port, NULL, 10);

    if (inet_pton(AF_INET, srv_ip, &serv_addr.sin_addr) <= 0) {
        fprintf(stderr, "pton failed\n");
        exit(EXIT_FAILURE);
    }

    if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr))) {
        fprintf(stderr, "connect failed\n");
        exit(EXIT_FAILURE);
    }


    for (int i = 0; i < n_opt; i++) {
        send(sockfd, &i_opt, 1, 0);
        sleep(i_opt);
    }

    return 0;
}









#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <wait.h>
#include <pthread.h>

int convertToInt(char a[1024]){
    int i = 0;
    int num = 0;
    while (a[i] != 0)
    {
        num =  (a[i])  + (num * 10);
        i++;
    }
    return num;;
}

void serve(int sockcl) {
    char buff[1024] = {0};

    while (read(sockcl, buff, 1024)) {
        int a = convertToInt(buff);
        fprintf(stdout, "Client: %d. Data: %d\n", sockcl-3, a);
    }
    exit(EXIT_SUCCESS);
}

void *killerthread(void *args) {
    while (1)
        waitpid(-1, NULL, 0);
}

int main(int argc, char **argv) {
    int sockfd;
    struct sockaddr_in addr;
    socklen_t addrlen = sizeof(addr);

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        fprintf(stderr, "socket failed\n");
        exit(EXIT_FAILURE);
    }

    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = INADDR_ANY;
    addr.sin_port = 0;

    if (bind(sockfd, (struct sockaddr *)&addr, addrlen) < 0) {
        fprintf(stderr, "bind failed\n");
        exit(EXIT_FAILURE);
    }

    getsockname(sockfd, (struct sockaddr *)&addr, &addrlen);
    fprintf(stdout, "bound to port: %d\n", addr.sin_port);

    if (listen(sockfd, 3) < 0) {
        fprintf(stderr, "listen failed\n");
        exit(EXIT_FAILURE);
    }

    pthread_t threadid;
    pthread_create(&threadid, NULL, killerthread, NULL);

    while (1) {
        int clientfd;
        pid_t pid;

        if ((clientfd = accept(sockfd, (struct sockaddr *)&addr, &addrlen)) < 0) {
            fprintf(stderr, "accept failed\n");
        }

        if ((pid = fork()) < 0) {
            fprintf(stderr, "fork failed\n");
        }

        if (pid == 0) {
            fprintf(stdout, "new client connected. fork created\n");
            serve(clientfd);
        }
    }
}