ssh.c

      if(rc == LIBSSH2_ERROR_EAGAIN) {
        break;
      }
      else if(rc < 0) {
        infof(data, "Failed to disconnect libssh2 session\n");
      }
    }

    Curl_safefree(sshc->homedir);
    sshc->homedir = NULL;

    state(conn, SSH_SESSION_FREE);
    break;

  case SSH_SESSION_FREE:
    if(sshc->ssh_session) {
      rc = libssh2_session_free(sshc->ssh_session);
      if(rc == LIBSSH2_ERROR_EAGAIN) {
        break;
      }
      else if(rc < 0) {
        infof(data, "Failed to free libssh2 session\n");
      }
      sshc->ssh_session = NULL;
    }
    sshc->nextstate = SSH_NO_STATE;
    state(conn, SSH_STOP);
    result = sshc->actualcode;
    break;

  case SSH_QUIT:
    /* fallthrough, just stop! */
  default:
    /* internal error */
    sshc->nextstate = SSH_NO_STATE;
    state(conn, SSH_STOP);
    break;
  }

  if(rc == LIBSSH2_ERROR_EAGAIN) {
    /* we would block, we need to wait for the socket to be ready (in the
       right direction too)! */
    *block = TRUE;
  }

  return result;
}

/* called repeatedly until done from multi.c */
static CURLcode ssh_multi_statemach(struct connectdata *conn, bool *done)
{
  struct ssh_conn *sshc = &conn->proto.sshc;
  CURLcode result = CURLE_OK;
  bool block_we_ignore; /* we don't care about EAGAIN at this point, but TODO:
                           we _should_ store the status and use that to
                           provide a ssh_getsock() implementation */

  result = ssh_statemach_act(conn, &block_we_ignore);
  *done = (bool)(sshc->state == SSH_STOP);

  return result;
}

static CURLcode ssh_easy_statemach(struct connectdata *conn)
{
  struct ssh_conn *sshc = &conn->proto.sshc;
  CURLcode result = CURLE_OK;

  while((sshc->state != SSH_STOP) && !result) {
    bool block;
    result = ssh_statemach_act(conn, &block);

#ifdef HAVE_LIBSSH2_SESSION_BLOCK_DIRECTION
    if((CURLE_OK == result) && block) {
      int dir = libssh2_session_block_directions(sshc->ssh_session);
      curl_socket_t sock = conn->sock[FIRSTSOCKET];
      curl_socket_t fd_read = CURL_SOCKET_BAD;
      curl_socket_t fd_write = CURL_SOCKET_BAD;
      if (LIBSSH2_SESSION_BLOCK_INBOUND & dir) {
        fd_read = sock;
      }
      if (LIBSSH2_SESSION_BLOCK_OUTBOUND & dir) {
        fd_write = sock;
      }
      /* wait for the socket to become ready */
      Curl_socket_ready(fd_read, fd_write, 1000); /* ignore result */
    }
#endif

  }

  return result;
}

/*
 * SSH setup and connection
 */
static CURLcode ssh_init(struct connectdata *conn)
{
  struct SessionHandle *data = conn->data;
  struct SSHPROTO *ssh;
  struct ssh_conn *sshc = &conn->proto.sshc;

  sshc->actualcode = CURLE_OK; /* reset error code */
  sshc->secondCreateDirs =0;   /* reset the create dir attempt state variable */

  if(data->state.proto.ssh)
    return CURLE_OK;

  ssh = calloc(sizeof(struct SSHPROTO), 1);
  if(!ssh)
    return CURLE_OUT_OF_MEMORY;

  data->state.proto.ssh = ssh;

  return CURLE_OK;
}

/*
 * Curl_ssh_connect() gets called from Curl_protocol_connect() to allow us to
 * do protocol-specific actions at connect-time.
 */
static CURLcode ssh_connect(struct connectdata *conn, bool *done)
{
#ifdef CURL_LIBSSH2_DEBUG
  curl_socket_t sock;
#endif
  struct ssh_conn *ssh;
  CURLcode result;
  struct SessionHandle *data = conn->data;

  /* We default to persistent connections. We set this already in this connect
     function to make the re-use checks properly be able to check this bit. */
  conn->bits.close = FALSE;

  /* If there already is a protocol-specific struct allocated for this
     sessionhandle, deal with it */
  Curl_reset_reqproto(conn);

  result = ssh_init(conn);
  if(result)
    return result;

  ssh = &conn->proto.sshc;

#ifdef CURL_LIBSSH2_DEBUG
  if(conn->user) {
    infof(data, "User: %s\n", conn->user);
  }
  if(conn->passwd) {
    infof(data, "Password: %s\n", conn->passwd);
  }
  sock = conn->sock[FIRSTSOCKET];
#endif /* CURL_LIBSSH2_DEBUG */

  ssh->ssh_session = libssh2_session_init_ex(libssh2_malloc, libssh2_free,
                                             libssh2_realloc, conn);
  if(ssh->ssh_session == NULL) {
    failf(data, "Failure initialising ssh session");
    return CURLE_FAILED_INIT;
  }

#ifdef CURL_LIBSSH2_DEBUG
  libssh2_trace(ssh->ssh_session, LIBSSH2_TRACE_CONN|LIBSSH2_TRACE_TRANS|
                LIBSSH2_TRACE_KEX|LIBSSH2_TRACE_AUTH|LIBSSH2_TRACE_SCP|
                LIBSSH2_TRACE_SFTP|LIBSSH2_TRACE_ERROR|
                LIBSSH2_TRACE_PUBLICKEY);
  infof(data, "SSH socket: %d\n", sock);
#endif /* CURL_LIBSSH2_DEBUG */

  state(conn, SSH_S_STARTUP);

  if(data->state.used_interface == Curl_if_multi)
    result = ssh_multi_statemach(conn, done);
  else {
    result = ssh_easy_statemach(conn);
    if(!result)
      *done = TRUE;
  }

  return result;
}

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

static
CURLcode scp_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_SCP_TRANS_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);
    *dophase_done = TRUE; /* with the easy interface we are done here */
  }
  *connected = conn->bits.tcpconnect;

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

  return result;
}

/* called from multi.c while DOing */
static CURLcode scp_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;
}

/*
 * The DO function is generic for both protocols. There was previously two
 * separate ones but this way means less duplicated code.
 */

static CURLcode ssh_do(struct connectdata *conn, bool *done)
{
  CURLcode res;
  bool connected = 0;
  struct SessionHandle *data = conn->data;

  *done = FALSE; /* default to false */

  /*
    Since connections can be re-used between SessionHandles, this might be a
    connection already existing but on a fresh SessionHandle struct so we must
    make sure we have a good 'struct SSHPROTO' to play with. For new
    connections, the struct SSHPROTO is allocated and setup in the
    ssh_connect() function.
  */
  Curl_reset_reqproto(conn);
  res = ssh_init(conn);
  if(res)
    return res;

  data->req.size = -1; /* make sure this is unknown at this point */

  Curl_pgrsSetUploadCounter(data, 0);
  Curl_pgrsSetDownloadCounter(data, 0);
  Curl_pgrsSetUploadSize(data, 0);
  Curl_pgrsSetDownloadSize(data, 0);

  if(conn->protocol & PROT_SCP)
    res = scp_perform(conn, &connected,  done);
  else
    res = sftp_perform(conn, &connected,  done);

  return res;
}

/* 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 scp_disconnect(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;

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

  if(conn->proto.sshc.ssh_session) {
    /* only if there's a session still around to use! */

    state(conn, SSH_SESSION_DISCONNECT);

    result = ssh_easy_statemach(conn);
  }

  return result;
}

/* generic done function for both SCP and SFTP called from their specific
   done functions */
static CURLcode ssh_done(struct connectdata *conn, CURLcode status)
{
  CURLcode result = CURLE_OK;
  bool done = FALSE;

  if(status == CURLE_OK) {
    /* run the state-machine */
    if(conn->data->state.used_interface == Curl_if_multi) {
      result = ssh_multi_statemach(conn, &done);
    }
    else {
      result = ssh_easy_statemach(conn);
      done = TRUE;
    }
  }
  else {
    result = status;
    done = TRUE;
  }

  if(done) {
    struct SSHPROTO *sftp_scp = conn->data->state.proto.ssh;

    Curl_safefree(sftp_scp->path);
    sftp_scp->path = NULL;
    Curl_pgrsDone(conn);
  }

  return result;
}


static CURLcode scp_done(struct connectdata *conn, CURLcode status,
                         bool premature)
{
  (void)premature; /* not used */

  if(status == CURLE_OK)
    state(conn, SSH_SCP_DONE);

  return ssh_done(conn, status);

}

/* return number of received (decrypted) bytes */
ssize_t Curl_scp_send(struct connectdata *conn, int sockindex,
                      const void *mem, size_t len)
{
  ssize_t nwrite;
  (void)sockindex; /* we only support SCP on the fixed known primary socket */

  /* libssh2_channel_write() returns int! */
  nwrite = (ssize_t)
    libssh2_channel_write(conn->proto.sshc.ssh_channel, mem, len);
  if(nwrite == LIBSSH2_ERROR_EAGAIN)
    return 0;

  return nwrite;
}

/*
 * If the read would block (EWOULDBLOCK) we return -1. Otherwise we return
 * a regular CURLcode value.
 */
ssize_t Curl_scp_recv(struct connectdata *conn, int sockindex,
                      char *mem, size_t len)
{
  ssize_t nread;
  (void)sockindex; /* we only support SCP on the fixed known primary socket */

  /* libssh2_channel_read() returns int */
  nread = (ssize_t)
    libssh2_channel_read(conn->proto.sshc.ssh_channel, mem, len);
  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);
    *dophase_done = TRUE; /* with the easy interface we are done here */
  }
  *connected = conn->bits.tcpconnect;

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

  return result;
}

/* called from 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)
{
  CURLcode result = CURLE_OK;

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

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

  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);
  }

  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) {
    /* Before we shut down, see if there are any post-quote commands to send: */
    if(!status && !premature && conn->data->set.postquote) {
      sshc->nextstate = SSH_SFTP_CLOSE;
      state(conn, SSH_SFTP_POSTQUOTE_INIT);
    }
    else
      state(conn, SSH_SFTP_CLOSE);
  }
  return ssh_done(conn, status);
}

/* return number of sent bytes */
ssize_t Curl_sftp_send(struct connectdata *conn, int sockindex,
                       const void *mem, size_t len)
{
  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);
  if(nwrite == LIBSSH2_ERROR_EAGAIN)
    return 0;

  return nwrite;
}

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

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

  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);
    *path = NULL;
    return CURLE_QUOTE_ERROR;
}


static const char *sftp_libssh2_strerror(unsigned long 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 */