curl_ssh.c

    libssh2_channel_read(conn->proto.sshc.ssh_channel, mem, len);

  ssh_block2waitfor(conn, (nread == LIBSSH2_ERROR_EAGAIN)?TRUE:FALSE);
  if(nread == LIBSSH2_ERROR_EAGAIN) {
    *err = CURLE_AGAIN;
    nread = -1;
  }

  return nread;
}

/*
 * =============== SFTP ===============
 */

/*
 ***********************************************************************
 *
 * sftp_perform()
 *
 * This is the actual DO function for SFTP. Get a file/directory according to
 * the options previously setup.
 */

static
CURLcode sftp_perform(struct connectdata *conn,
                      bool *connected,
                      bool *dophase_done)
{
  CURLcode result = CURLE_OK;

  DEBUGF(infof(conn->data, "DO phase starts\n"));

  *dophase_done = FALSE; /* not done yet */

  /* start the first command in the DO phase */
  state(conn, SSH_SFTP_QUOTE_INIT);

  /* run the state-machine */
  if(conn->data->state.used_interface == Curl_if_multi) {
    result = ssh_multi_statemach(conn, dophase_done);
  }
  else {
    result = ssh_easy_statemach(conn, FALSE);
    *dophase_done = TRUE; /* with the easy interface we are done here */
  }
  *connected = conn->bits.tcpconnect[FIRSTSOCKET];

  if(*dophase_done) {
    DEBUGF(infof(conn->data, "DO phase is complete\n"));
  }

  return result;
}

/* called from curl_multi.c while DOing */
static CURLcode sftp_doing(struct connectdata *conn,
                           bool *dophase_done)
{
  CURLcode result;
  result = ssh_multi_statemach(conn, dophase_done);

  if(*dophase_done) {
    DEBUGF(infof(conn->data, "DO phase is complete\n"));
  }
  return result;
}

/* BLOCKING, but the function is using the state machine so the only reason
   this is still blocking is that the multi interface code has no support for
   disconnecting operations that takes a while */
static CURLcode sftp_disconnect(struct connectdata *conn, bool dead_connection)
{
  CURLcode result = CURLE_OK;
  (void) dead_connection;

  DEBUGF(infof(conn->data, "SSH DISCONNECT starts now\n"));

  Curl_safefree(conn->data->state.proto.ssh);

  if(conn->proto.sshc.ssh_session) {
    /* only if there's a session still around to use! */
    state(conn, SSH_SFTP_SHUTDOWN);
    result = ssh_easy_statemach(conn, FALSE);
  }

  DEBUGF(infof(conn->data, "SSH DISCONNECT is done\n"));

  return result;

}

static CURLcode sftp_done(struct connectdata *conn, CURLcode status,
                               bool premature)
{
  struct ssh_conn *sshc = &conn->proto.sshc;

  if(status == CURLE_OK) {
    /* Post quote commands are executed after the SFTP_CLOSE state to avoid
       errors that could happen due to open file handles during POSTQUOTE
       operation */
    if(!status && !premature && conn->data->set.postquote) {
      sshc->nextstate = SSH_SFTP_POSTQUOTE_INIT;
      state(conn, SSH_SFTP_CLOSE);
    }
    else
      state(conn, SSH_SFTP_CLOSE);
  }
  return ssh_done(conn, status);
}

/* return number of sent bytes */
static ssize_t sftp_send(struct connectdata *conn, int sockindex,
                         const void *mem, size_t len, CURLcode *err)
{
  ssize_t nwrite;   /* libssh2_sftp_write() used to return size_t in 0.14
                       but is changed to ssize_t in 0.15. These days we don't
                       support libssh2 0.15*/
  (void)sockindex;

  nwrite = libssh2_sftp_write(conn->proto.sshc.sftp_handle, mem, len);

  ssh_block2waitfor(conn, (nwrite == LIBSSH2_ERROR_EAGAIN)?TRUE:FALSE);

  if(nwrite == LIBSSH2_ERROR_EAGAIN) {
    *err = CURLE_AGAIN;
    nwrite = 0;
  }
  else if(nwrite < LIBSSH2_ERROR_NONE) {
    *err = libssh2_session_error_to_CURLE((int)nwrite);
    nwrite = -1;
  }

  return nwrite;
}

/*
 * Return number of received (decrypted) bytes
 */
static ssize_t sftp_recv(struct connectdata *conn, int sockindex,
                         char *mem, size_t len, CURLcode *err)
{
  ssize_t nread;
  (void)sockindex;

  nread = libssh2_sftp_read(conn->proto.sshc.sftp_handle, mem, len);

  ssh_block2waitfor(conn, (nread == LIBSSH2_ERROR_EAGAIN)?TRUE:FALSE);

  if(nread == LIBSSH2_ERROR_EAGAIN) {
    *err = CURLE_AGAIN;
    nread = -1;
  }
  return nread;
}

/* The get_pathname() function is being borrowed from OpenSSH-sftp.c
   version 4.6p1. */
/*
 * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
static CURLcode
get_pathname(const char **cpp, char **path)
{
  const char *cp = *cpp, *end;
  char quot;
  unsigned int i, j;
  static const char WHITESPACE[] = " \t\r\n";

  cp += strspn(cp, WHITESPACE);
  if(!*cp) {
    *cpp = cp;
    *path = NULL;
    return CURLE_QUOTE_ERROR;
  }

  *path = malloc(strlen(cp) + 1);
  if(*path == NULL)
    return CURLE_OUT_OF_MEMORY;

  /* Check for quoted filenames */
  if(*cp == '\"' || *cp == '\'') {
    quot = *cp++;

    /* Search for terminating quote, unescape some chars */
    for(i = j = 0; i <= strlen(cp); i++) {
      if(cp[i] == quot) {  /* Found quote */
        i++;
        (*path)[j] = '\0';
        break;
      }
      if(cp[i] == '\0') {  /* End of string */
        /*error("Unterminated quote");*/
        goto fail;
      }
      if(cp[i] == '\\') {  /* Escaped characters */
        i++;
        if(cp[i] != '\'' && cp[i] != '\"' &&
            cp[i] != '\\') {
          /*error("Bad escaped character '\\%c'",
              cp[i]);*/
          goto fail;
        }
      }
      (*path)[j++] = cp[i];
    }

    if(j == 0) {
      /*error("Empty quotes");*/
      goto fail;
    }
    *cpp = cp + i + strspn(cp + i, WHITESPACE);
  }
  else {
    /* Read to end of filename */
    end = strpbrk(cp, WHITESPACE);
    if(end == NULL)
      end = strchr(cp, '\0');
    *cpp = end + strspn(end, WHITESPACE);

    memcpy(*path, cp, end - cp);
    (*path)[end - cp] = '\0';
  }
  return CURLE_OK;

  fail:
    Curl_safefree(*path);
    return CURLE_QUOTE_ERROR;
}


static const char *sftp_libssh2_strerror(int err)
{
  switch (err) {
    case LIBSSH2_FX_NO_SUCH_FILE:
      return "No such file or directory";

    case LIBSSH2_FX_PERMISSION_DENIED:
      return "Permission denied";

    case LIBSSH2_FX_FAILURE:
      return "Operation failed";

    case LIBSSH2_FX_BAD_MESSAGE:
      return "Bad message from SFTP server";

    case LIBSSH2_FX_NO_CONNECTION:
      return "Not connected to SFTP server";

    case LIBSSH2_FX_CONNECTION_LOST:
      return "Connection to SFTP server lost";

    case LIBSSH2_FX_OP_UNSUPPORTED:
      return "Operation not supported by SFTP server";

    case LIBSSH2_FX_INVALID_HANDLE:
      return "Invalid handle";

    case LIBSSH2_FX_NO_SUCH_PATH:
      return "No such file or directory";

    case LIBSSH2_FX_FILE_ALREADY_EXISTS:
      return "File already exists";

    case LIBSSH2_FX_WRITE_PROTECT:
      return "File is write protected";

    case LIBSSH2_FX_NO_MEDIA:
      return "No media";

    case LIBSSH2_FX_NO_SPACE_ON_FILESYSTEM:
      return "Disk full";

    case LIBSSH2_FX_QUOTA_EXCEEDED:
      return "User quota exceeded";

    case LIBSSH2_FX_UNKNOWN_PRINCIPLE:
      return "Unknown principle";

    case LIBSSH2_FX_LOCK_CONFlICT:
      return "File lock conflict";

    case LIBSSH2_FX_DIR_NOT_EMPTY:
      return "Directory not empty";

    case LIBSSH2_FX_NOT_A_DIRECTORY:
      return "Not a directory";

    case LIBSSH2_FX_INVALID_FILENAME:
      return "Invalid filename";

    case LIBSSH2_FX_LINK_LOOP:
      return "Link points to itself";
  }
  return "Unknown error in libssh2";
}

#endif /* USE_LIBSSH2 */