ftpc_cmd.c

/****************************************************************************
 * apps/netutils/ftpc/ftpc_cmd.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include "ftpc_config.h"

#include <stdlib.h>
#include <strings.h>
#include <stdarg.h>
#include <errno.h>
#include <debug.h>

#include "ftpc_internal.h"

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: ftpc_restore
 *
 * Description:
 *   Restore the connection to the server and log in again.
 *
 ****************************************************************************/

#ifdef CONFIG_FTP_AUTORECONNECT
static int ftpc_restore(struct ftpc_session_s *session)
{
  int ret;

  if (session)
    {
      /* Set the initial directory to the last valid current directory */

      free(session->initrdir);
      session->initrdir = ftpc_dequote(session->currdir);

      /* Reconnect to the server */

      ret = ftpc_reconnect(session);
      if (ret == 0)
        {
          /* Log into the server */

          ret = ftpc_relogin(session);
        }
      else
        {
          /* Failed to reconnect to the server */

          ftpc_reset(session);
        }

      return ret;
    }

  return ERROR;
}
#endif

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: ftpc_cmd
 *
 * Description:
 *   Send the specified command to the server.
 *
 ****************************************************************************/

int ftpc_cmd(struct ftpc_session_s *session, const char *cmd, ...)
{
  va_list ap;
#ifdef CONFIG_FTP_AUTORECONNECT
  bool reconnect = false;
#endif
  int ret;

  /* Verify that we are still connected to the server */

  if (!ftpc_sockconnected(&session->cmd))
    {
      nwarn("WARNING: Cmd channel is not connected\n");
      goto errout;
    }

  /* Loop, reconnecting as necessary until the command is sent */

#ifdef CONFIG_FTP_AUTORECONNECT
  for (; ; )
#endif
    {
      /* Send the command */

      va_start(ap, cmd);
      ret = ftpc_sockvprintf(&session->cmd, cmd, ap);
      if (ret >= 0)
        {
          ret = ftpc_sockprintf(&session->cmd, "\r\n");
          if (ret >= 0)
            {
              ret = ftpc_sockflush(&session->cmd);
            }
        }

      va_end(ap);

      /* Check for an error in sending the data */

      if (ret < 0)
        {
          nerr("ERROR: Error sending cmd %s: %d\n", cmd, errno);
          goto errout;
        }

      /* Get the response to the command */

      ret = fptc_getreply(session);
      if (ret < 0)
        {
          nerr("ERROR: Error getting reply: %d\n", errno);
          goto errout;
        }

      /* Check for "421 Service not available, closing control connection" */

      if (session->code == 421)
        {
          /* Server is closing the control connection. */

          nwarn("WARNING: Server closed control connection\n");

          /* If we were previously logged in and this is not a QUIT command
           * then attempt to automatically reconnect to the server.
           */

#ifdef CONFIG_FTP_AUTORECONNECT
          if (ftpc_loggedin(session) && strcasecmp(cmd, "QUIT") != 0)
            {
              /* Don't try re-connecting more than once */

              if (reconnect)
                {
                  nwarn("WARNING: Reconnect failed\n");
                  goto errout;
                }
              else
                {
                  /* Try to restore the connection and, if successful,
                   * continue the loop and try to send the command again.
                   */

                  ninfo("Reconnecting...\n");
                  reconnect = true;
                  ret = ftpc_restore();
                  if (ret < 0)
                    {
                      nwarn("WARNING: Failed to restore the connection");
                      goto errout;
                    }

                  continue;
                }
            }
          else
#endif
            {
              /* Don't try to connect, just return an error (retaining
               * the session response code (421)
               */

              return ERROR;
            }
        }

      /* Error codes 5xx are Permanent Negative Completion. These can be
       * handled generically for all commands. An example is error code 530
       * which means 'not logged in'. The reply should include a string to
       * display to the user
       */

      else if (session->code > 500 && session->code < 600)
        {
          return ERROR;
        }

      /* The command was successfully sent */

      return OK;
    }

errout:
  session->code = -1;
  return ERROR;
}