Fossil

  if( pnRcvd ) *pnRcvd = transport.nRcvd;
  if( resetFlag ){
    transport.nSent = 0;
    transport.nRcvd = 0;
  }
}

/*
** Remove leading "-" characters from the input string.
**
** This prevents attacks that try to trick a victim into using
** a ssh:// URI with a carefully crafted hostname of other
** parameter that ends up being interpreted as a command-line
** option by "ssh".
*/
static const char *stripLeadingMinus(const char *z){
  while( z[0]=='-' ) z++;
  return z;
}

/*
** Default SSH command
*/
#ifdef _WIN32
static const char zDefaultSshCmd[] = "plink -ssh -T";
#else
static const char zDefaultSshCmd[] = "ssh -e none -T";
#endif

/*
** SSH initialization of the transport layer
*/
int transport_ssh_open(UrlData *pUrlData){
  /* For SSH we need to create and run SSH fossil http
  ** to talk to the remote machine.
  */
  char *zSsh;        /* The base SSH command */
  Blob zCmd;         /* The SSH command */
  char *zHost;       /* The host name to contact */
  int n;             /* Size of prefix string */

  socket_ssh_resolve_addr(pUrlData);
  zSsh = db_get("ssh-command", zDefaultSshCmd);
  blob_init(&zCmd, zSsh, -1);
  if( pUrlData->port!=pUrlData->dfltPort && pUrlData->port ){
#ifdef _WIN32
    blob_appendf(&zCmd, " -P %d", pUrlData->port);
#else
    blob_appendf(&zCmd, " -p %d", pUrlData->port);
#endif
  }
  if( g.fSshTrace ){
    fossil_force_newline();
    fossil_print("%s", blob_str(&zCmd));  /* Show the base of the SSH command */
  }
  if( pUrlData->user && pUrlData->user[0] ){
    zHost = mprintf("%s@%s", pUrlData->user, pUrlData->name);
    blob_append_escaped_arg(&zCmd, zHost);
    fossil_free(zHost);
  }else{
    zHost = mprintf("%s", pUrlData->name);
    blob_append_escaped_arg(&zCmd, pUrlData->name);
  }
  n = blob_size(&zCmd);
  blob_append(&zCmd, " ", 1);
  shell_escape(&zCmd, stripLeadingMinus(zHost));
  blob_append(&zCmd, " ", 1);
  shell_escape(&zCmd, mprintf("%s", pUrlData->fossil));
  blob_append_escaped_arg(&zCmd, pUrlData->fossil);
  blob_append(&zCmd, " test-http", 10);
  if( pUrlData->path && pUrlData->path[0] ){
    blob_append(&zCmd, " ", 1);
    blob_append_escaped_arg(&zCmd, pUrlData->path);
    shell_escape(&zCmd, mprintf("%s", stripLeadingMinus(pUrlData->path)));
  }else{
    fossil_fatal("ssh:// URI does not specify a path to the repository");
  }
  if( g.fSshTrace ){
    fossil_print("%s\n", blob_str(&zCmd)+n);  /* Show tail of SSH command */
    fossil_print("%s\n", blob_str(&zCmd));  /* Show the whole SSH command */
  }
  free(zHost);
  popen2(blob_str(&zCmd), &sshIn, &sshOut, &sshPid);
  if( sshPid==0 ){
    socket_set_errmsg("cannot start ssh tunnel using [%b]", &zCmd);
  }
  blob_reset(&zCmd);
  return sshPid==0;
}