S01_BSD_02_SERVER

/*
Napisz programy, które prześlą plik o rozmiarze większym od 1 MiB między
dwoma komputerami, z użyciem protokołu TCP/IP. Sprawdź , co się stanie, jeśli
plik będzie wysyłany w jednym komunikacie.
*/

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

#define FILENAME "received_file"
#define SERVER_PORT 1919
#define MAX_CLIENTS 5

void error_handler(const char *msg)
{
    perror(msg);
    exit(EXIT_FAILURE);
}

int main(void)
{
    int server_socket, client_socket;
    struct sockaddr_in server_addr, client_addr;
    socklen_t addrlen = sizeof(struct sockaddr);
    int file_size, remain_data;
    char buffer[BUFSIZ];
    ssize_t length;
    int fd;

    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(SERVER_PORT);
    server_addr.sin_addr.s_addr = INADDR_ANY;
    memset(server_addr.sin_zero, '\0', 8);

    if((server_socket = socket(AF_INET, SOCK_STREAM, 0)) == -1)
        error_handler("socket");
    if(bind(server_socket, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1)
        error_handler("bind");
    if(listen(server_socket, MAX_CLIENTS) == -1)
        error_handler("listen");

    printf("Oczekiwanie na polaczenie klienta...\n");

    if((client_socket = accept(server_socket, (struct sockaddr *)&client_addr, &addrlen)) == -1)
        error_handler("accept");

    printf("Klient polaczyl sie z serwerem!\n");

    if(recv(client_socket, buffer, BUFSIZ, 0) == -1)
        error_handler("read");
    file_size = atoi(buffer);

    printf("Odbieram plik o rozmiarze %d bajtow...\n", file_size);

    if((fd = open(FILENAME, O_RDWR | O_CREAT, 0755)) == -1)
        error_handler("open");

    remain_data = file_size;

    memset(buffer, '\0', BUFSIZ);
    while(((length = recv(client_socket, buffer, BUFSIZ, 0)) > 0) && (remain_data > 0)) {
        if(write(fd, buffer, length) == -1)
            error_handler("write");
        remain_data -= length;
    }

    if(length == -1)
        error_handler("recv");

    printf("Pomyslnie odebrano plik!\n");

    if(close(server_socket) == -1)
        error_handler("close");

    return EXIT_SUCCESS;
}