Program Statement

A minimal HTTP/1.0 server using the classic fork-per-client model:

/* webserver.c — minimal HTTP/1.0 server, fork-per-client */
int main(void) {
    int lfd = socket(AF_INET, SOCK_STREAM, 0), on = 1;
    setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
    struct sockaddr_in a = {0};
    a.sin_family = AF_INET; a.sin_port = htons(8080);
    a.sin_addr.s_addr = htonl(INADDR_ANY);
    bind(lfd, (struct sockaddr *)&a, sizeof(a));
    listen(lfd, 16);
    signal(SIGCHLD, SIG_IGN);                 /* auto-reap children */
    for (;;) {
        int cfd = accept(lfd, NULL, NULL);
        if (fork() == 0) {
            close(lfd);
            char req[4096];
            read(cfd, req, sizeof(req));      /* read request       */
            printf("request line: %.40s\n", req);
            const char *body = "<h1>Hello from my socket web server!</h1>";
            char resp[512];
            int len = snprintf(resp, sizeof(resp),
                "HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n"
                "Content-Length: %zu\r\n\r\n%s", strlen(body), body);
            write(cfd, resp, len);
            close(cfd); exit(0);
        }
        close(cfd);                           /* parent MUST close  */
    }
}

Testing

Open http://localhost:8080 in a browser.

Extension

Parse the request path and serve actual files from disk.

Theory Link

Unit 1 "Concurrent Servers" — note SO_REUSEADDR (restart the server while old connections sit in TIME_WAIT) and the parent's close(cfd) (without it the connection never fully closes because the descriptor's reference count stays above zero). Both are exam points.