ex1, 2 w5

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>

#define MAX_MESSAGE_SIZE 1024

int main(int argc, char *argv[]) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <number of subscribers>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    int num_subscribers = atoi(argv[1]);
    int pipe_fds[num_subscribers];
    char pipe_names[num_subscribers][20]; // "/tmp/ex1/sX" where X is the subscriber index
    char message[MAX_MESSAGE_SIZE];

    // Create named pipes for each subscriber
    for (int i = 1; i <= num_subscribers; i++) {
        snprintf(pipe_names[i - 1], sizeof(pipe_names[i - 1]), "/tmp/ex1/s%d", i);
        mkfifo(pipe_names[i - 1], 0666);
    }

    while (1) {
        // Read a message from stdin
        ssize_t bytes_read = read(STDIN_FILENO, message, MAX_MESSAGE_SIZE);

        if (bytes_read <= 0) {
            break; // Exit if stdin is closed or an error occurs
        }

        // Publish the message to all subscribers
        for (int i = 0; i < num_subscribers; i++) {
            pipe_fds[i] = open(pipe_names[i], O_WRONLY);
            write(pipe_fds[i], message, bytes_read);
            close(pipe_fds[i]);
        }
    }

    // Cleanup: Close and unlink named pipes
    for (int i = 0; i < num_subscribers; i++) {
        unlink(pipe_names[i]);
    }

    return 0;
}