receive.c

#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int main() {

  const int PORT = 8080;
  const int BUFFER_SIZE = 1024;

  int client_socket;
  struct sockaddr_in server_addr, client_addr;
  char buffer[BUFFER_SIZE];
  socklen_t addr_len = sizeof(client_addr);

  int sock = socket(AF_INET, SOCK_STREAM, 0);
  if (sock < 0) {
    perror("Socket failed");
    exit(EXIT_FAILURE);
  }

  server_addr.sin_family = AF_INET;
  server_addr.sin_addr.s_addr = INADDR_ANY;
  server_addr.sin_port = htons(PORT);
  if (bind(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
    perror("Bind failed");
    exit(EXIT_FAILURE);
  }

  if (listen(sock, 1) < 0) {
    perror("Listening failed");
    exit(EXIT_FAILURE);
  }
  printf("Server listening on port %d...\n", PORT);

  client_socket = accept(sock, (struct sockaddr *)&client_addr, &addr_len);
  if (client_socket < 0) {
    perror("Accept failed");
    exit(EXIT_FAILURE);
  }
  printf("Client connected.\n");

  uint32_t argc;
  if (read(client_socket, &argc, sizeof(argc)) < 0) {
    perror("Failed to read argc");
    close(client_socket);
    close(sock);
    exit(EXIT_FAILURE);
  }
  argc = ntohl(argc);
  printf("%zu file(s) will be received.\n", (unsigned long)argc);

  char title_list[argc][BUFFER_SIZE];
  for (int i = 0; i < argc;) {
    if (read(client_socket, title_list[i], BUFFER_SIZE) <= 0) {
      perror("Failed to read file name");
      close(client_socket);
      close(sock);
      exit(EXIT_FAILURE);
    }
    if (title_list[i][0]) {
      i++;
    }
  }

  for (int i = 0; i < argc; i++) {
    FILE *f = fopen(title_list[i], "wb");
    printf("Receiving file %d: %s\n", i + 1, title_list[i]);
    if (f == NULL) {
      perror("Error opening file for writing");
      close(client_socket);
      close(sock);
      exit(EXIT_FAILURE);
    }
    while (1) {
      memset(buffer, 0, BUFFER_SIZE);
      ssize_t bytes_read = read(client_socket, buffer, BUFFER_SIZE);
      if (bytes_read < 0) {
        perror("Error reading from client socket");
        fclose(f);
        close(client_socket);
        close(sock);
        exit(EXIT_FAILURE);
      }
      if (bytes_read == 0) {
        break;
      }
      if (fwrite(buffer, sizeof(char), bytes_read, f) != bytes_read) {
        perror("Error writing to file");
        fclose(f);
        close(client_socket);
        close(sock);
        exit(EXIT_FAILURE);
      }
    }
    fclose(f);
  }
  close(client_socket);
  close(sock);
  return 0;
}