// perform FTP TYPE command, switch binary mode on and off
void command_type(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int len = strlen(line);
if (len < 6)
{
send_code(client_info->fd, 500);
return;
}
char * param = line + 5;
if (strcmp(param, "A") == 0) client_info->binary_flag = 0;
else if (strcmp(param, "A N") == 0) client_info->binary_flag = 0;
else if (strcmp(param, "I") == 0) client_info->binary_flag = 1;
else if (strcmp(param, "L 8") == 0) client_info->binary_flag = 1;
else
{
send_code(client_info->fd, 500);
return;
}
send_code(client_info->fd, 200);
}
// perform FTP CWD command, changes directory
void command_cwd(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int len = strlen(line);
if (len < 5)
{
send_code(client_info->fd, 500);
return;
}
char dirbackup[PATH_MAX + 1] = { 0 };
strncpy(dirbackup, client_info->dir, PATH_MAX);
char * dir = line + 4;
if (dir[0] == '/')
{
strncpy(client_info->dir, dir, PATH_MAX);
}
else
{
strncat(client_info->dir, dir, PATH_MAX);
strncat(client_info->dir, "/", PATH_MAX);
}
char dirbuf[PATH_MAX + 1] = { 0 };
snprintf(dirbuf, PATH_MAX, "%s%s", basedir, client_info->dir);
char pathbuf[PATH_MAX + 1] = { 0 };
if (! realpath(dirbuf, pathbuf))
{
strncpy(client_info->dir, dirbackup, PATH_MAX);
send_code(client_info->fd, 550);
return;
}
strncpy(client_info->dir, pathbuf, PATH_MAX);
if (strlen(client_info->dir) < strlen(basedir))
{
strncpy(client_info->dir, dirbackup, PATH_MAX);
send_code(client_info->fd, 550);
return;
}
memmove(client_info->dir, client_info->dir + strlen(basedir), strlen(client_info->dir) - strlen(basedir) + 1);
if (client_info->dir[strlen(client_info->dir) - 1] != '/')
strncat(client_info->dir, "/", PATH_MAX);
send_code(client_info->fd, 250);
}
// perform FTP RETR command, sends a file to the client
void command_retr(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int len = strlen(line);
if (len < 6)
{
send_code(client_info->fd, 500);
return;
}
char * filename = line + 5;
char filenamebuf[PATH_MAX + 1] = { 0 };
if (filename[0] == '/')
{
snprintf(filenamebuf, PATH_MAX, "%s%s", basedir, filename);
}
else
{
snprintf(filenamebuf, PATH_MAX, "%s%s%s", basedir, client_info->dir, filename);
}
int fd = open(filenamebuf, O_RDONLY);
if (fd == -1)
{
// cannot open file
send_code(client_info->fd, 550);
return;
}
send_code(client_info->fd, 150);
open_data_connection(client_info);
while (1)
{
char buf[FILE_READ_BUFFER_SIZE];
int bytes_read = read(fd, buf, FILE_READ_BUFFER_SIZE);
if (bytes_read == 0) break;
if (bytes_read == -1) epicfail("read");
int res = data_connection_write_buffer(client_info, buf, bytes_read);
if (res == -1) break;
}
close(fd);
close_data_connection(client_info);
send_code(client_info->fd, 226);
}
// perform FTP PWD command, prints current directory
void command_pwd(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int len = strlen(line);
if (len != 3)
{
send_code(client_info->fd, 500);
return;
}
send_code_param(client_info->fd, 257, client_info->dir);
}
// perform FTP SYST command, identify as a standard UNIX FTP server
void command_syst(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int len = strlen(line);
if (len != 4)
{
send_code(client_info->fd, 500);
return;
}
send_code_param(client_info->fd, 215, "UNIX Type: L8");
}
// perform FTP USER command, take any username as valid
void command_user(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int len = strlen(line);
if (len < 6)
{
send_code(client_info->fd, 500);
return;
}
send_code(client_info->fd, 331);
}
// perform FTP PASV command, prepare for passive data connection
void command_pasv(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int len = strlen(line);
if (len != 4)
{
send_code(client_info->fd, 500);
return;
}
if (client_info->passive_fd != 0)
{
close(client_info->passive_fd);
client_info->passive_fd = 0;
}
struct sockaddr_in s;
socklen_t l;
l = sizeof(s);
getsockname(client_info->fd, (struct sockaddr *)&s, &l);
char * ip = inet_ntoa(s.sin_addr);
if (! ip) epicfail("inet_ntoa");
client_info->data_connection_mode = CONN_MODE_PASSIVE;
client_info->passive_fd = create_tcp_server_socket(ip, 0);
l = sizeof(s);
getsockname(client_info->passive_fd, (struct sockaddr *)&s, &l);
int port = ntohs(s.sin_port);
int ip1, ip2, ip3, ip4, port1, port2;
if (sscanf(ip, "%d.%d.%d.%d", &ip1, &ip2, &ip3, &ip4) != 4) epicfail("command_pasv");
port1 = port >> 8;
port2 = port & 0xff;
char p[64];
sprintf(p, "%d,%d,%d,%d,%d,%d", ip1, ip2, ip3, ip4, port1, port2);
send_code_param(client_info->fd, 227, p);
}
static int client_input_received(struct client *client, size_t bytesRead)
{
char *line;
int ret;
fifo_buffer_append(client->input, bytesRead);
/* process all lines */
while ((line = client_read_line(client)) != NULL) {
ret = client_process_line(client, line);
g_free(line);
if (ret == COMMAND_RETURN_KILL ||
ret == COMMAND_RETURN_CLOSE)
return ret;
if (client_is_expired(client))
return COMMAND_RETURN_CLOSE;
}
return 0;
}
// perform FTP PORT command, prepare for active data connection
void command_port(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int ip1, ip2, ip3, ip4, port1, port2;
if (sscanf(line + 5, "%d,%d,%d,%d,%d,%d", &ip1, &ip2, &ip3, &ip4, &port1, &port2) != 6)
{
send_code(client_info->fd, 500);
return;
}
client_info->data_connection_mode = CONN_MODE_ACTIVE;
memset(&(client_info->active_addr), 0, sizeof(client_info->active_addr));
client_info->active_addr.sin_family = AF_INET;
char buf_addr[32];
sprintf(buf_addr, "%d.%d.%d.%d", ip1, ip2, ip3, ip4);
inet_pton(AF_INET, buf_addr, &(client_info->active_addr.sin_addr));
client_info->active_addr.sin_port = htons((port1 << 8) + port2);
send_code(client_info->fd, 200);
}
// reads a line from the client buffer
void get_line(int fd, char * line, char * buf, int * buffer_pos)
{
client_read_line(fd, buf, buffer_pos);
extract_line(line, buf, buffer_pos);
}
// perform FTP LIST command, sends a directory listing to the client
void command_list(CLIENT_INFO * client_info)
{
char line[BUFFER_SIZE] = { 0 };
client_read_line(client_info->fd, client_info->buf, &client_info->buffer_pos);
extract_line(line, client_info->buf, &client_info->buffer_pos);
int len = strlen(line);
char * path = NULL;
if (len != 4)
{
char * p = line + 5;
if (*p == '-')
{
while (*p && (*p != ' ')) p++;
}
while (*p && (*p == ' ')) p++;
path = p;
}
char dirbuf[PATH_MAX + 1] = { 0 };
snprintf(dirbuf, PATH_MAX, "%s%s", basedir, client_info->dir);
if (path)
{
if (path[0] == '/')
{
snprintf(dirbuf, PATH_MAX, "%s%s", basedir, path);
}
else
{
strcat(dirbuf, "/");
strcat(dirbuf, path);
}
}
char realpathbuf[PATH_MAX + 1] = { 0 };
if (! realpath(dirbuf, realpathbuf))
{
send_code(client_info->fd, 550);
return;
}
strcpy(dirbuf, realpathbuf);
if (dirbuf[strlen(dirbuf) - 1] != '/')
strncat(dirbuf, "/", PATH_MAX);
DIR * dirp = opendir(dirbuf);
if (! dirp)
{
send_code(client_info->fd, 550);
return;
}
send_code(client_info->fd, 150);
open_data_connection(client_info);
while (1)
{
struct dirent * entry = readdir(dirp);
if (! entry) break;
char filenamebuf[PATH_MAX + 1] = { 0 };
snprintf(filenamebuf, PATH_MAX, "%s%s", dirbuf, entry->d_name);
struct stat s;
if (stat(filenamebuf, &s) == -1)
{
// cannot stat
continue;
}
char buf[PATH_MAX + 128 + 1] = { 0 };
strmode(s.st_mode, buf);
unsigned int size = (unsigned int)s.st_size;
char date[64];
struct tm * ts = localtime(&s.st_mtime);
strftime(date, 64, "%b %e %Y", ts);
sprintf(buf + 11, "%3d %-8d %-8d %8u %s %s\r\n", s.st_nlink, (int)s.st_uid, (int)s.st_gid, size, date, entry->d_name);
data_connection_write_string(client_info, buf);
}
close_data_connection(client_info);
send_code(client_info->fd, 226);
}
