server.c

#include "ftp.h"

typedef struct {
    int socket;
    struct sockaddr_in address;
} client_info_t;

int list_directory(char* buffer, size_t buffer_size) {
    FILE* fp = popen("ls", "r");
    if (!fp) return -1;

    size_t bytes_read = fread(buffer, 1, buffer_size - 1, fp);
    buffer[bytes_read] = '\0';
    pclose(fp);
    return bytes_read;
}

void* handle_client(void* arg) {
    client_info_t* client = (client_info_t*)arg;
    int client_socket = client->socket;
    char buffer[BUFFER_SIZE];
    char command[64], filename[MAX_FILENAME];

    printf("Client connected from %s\n", inet_ntoa(client->address.sin_addr));
    send_response(client_socket, RESP_OK, "FTP Server Ready");

    while (1) {
        memset(buffer, 0, sizeof(buffer));

        if (recv(client_socket, buffer, sizeof(buffer) - 1, 0) <= 0) break;

        if (sscanf(buffer, "%63s %255s", command, filename) < 1) {
            send_response(client_socket, RESP_ERROR, "Invalid command");
            continue;
        }

        printf("Command: %s\n", command);

        if (strcmp(command, CMD_LIST) == 0) {
            char file_list[BUFFER_SIZE];
            if (list_directory(file_list, sizeof(file_list)) >= 0) {
                send_response(client_socket, RESP_OK, "File list follows");
                send(client_socket, file_list, strlen(file_list), 0);
            } else {
                send_response(client_socket, RESP_ERROR, "Cannot list directory");
            }

        } else if (strcmp(command, CMD_GET) == 0) {
            if (access(filename, F_OK) == 0) {
                send_response(client_socket, RESP_OK, "Sending file");
                send_file(client_socket, filename);
            } else {
                send_response(client_socket, RESP_NOT_FOUND, "File not found");
            }

        } else if (strcmp(command, CMD_PUT) == 0) {
            send_response(client_socket, RESP_OK, "Ready to receive");
            if (receive_file(client_socket, filename) == 0) {
                printf("File %s uploaded successfully\n", filename);
            }

        } else if (strcmp(command, CMD_QUIT) == 0) {
            send_response(client_socket, RESP_OK, "Goodbye");
            break;

        } else {
            send_response(client_socket, RESP_ERROR, "Unknown command");
        }
    }

    printf("Client disconnected\n");
    close(client_socket);
    free(client);
    return NULL;
}