/*
   Copyright (c) 2013, 2021, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#include "named_pipe_connection.h"

#include <AclAPI.h>                     // Windows access control API
#include "violite.h"                    // Vio
#include "channel_info.h"               // Channel_info
#include "connection_handler_manager.h" // Connection_handler_manager
#include "log.h"                        // sql_print_error
#include "named_pipe.h"                 // create_server_named_pipe.
#include "sql_class.h"                  // THD


///////////////////////////////////////////////////////////////////////////
// Channel_info_named_pipe implementation
///////////////////////////////////////////////////////////////////////////

/**
  This class abstracts the info. about  windows named pipe of communication
  with server from client.
*/
class Channel_info_named_pipe : public Channel_info
{
  // Handle to named pipe.
  HANDLE m_handle;

protected:
  virtual Vio* create_and_init_vio() const
  {
    return vio_new_win32pipe(m_handle);
  }

public:
  /**
    Constructor that sets the pipe handle

    @param handle    connected pipe handle
  */
  Channel_info_named_pipe(HANDLE handle)
  : m_handle(handle)
  { }

  virtual THD* create_thd()
  {
    THD* thd= Channel_info::create_thd();

    if (thd != NULL)
      thd->security_context()->set_host_ptr(my_localhost, strlen(my_localhost));
    return thd;
  }

  virtual void send_error_and_close_channel(uint errorcode,
                                            int error,
                                            bool senderror)
  {
    Channel_info::send_error_and_close_channel(errorcode, error, senderror);

    DisconnectNamedPipe(m_handle);
    CloseHandle(m_handle);
  }
};


///////////////////////////////////////////////////////////////////////////
// Named_pipe_listener implementation
///////////////////////////////////////////////////////////////////////////

bool Named_pipe_listener::setup_listener()
{
  m_connect_overlapped.hEvent= CreateEvent(NULL, TRUE, FALSE, NULL);
  if (!m_connect_overlapped.hEvent)
  {
    sql_print_error("Can't create event, last error=%u", GetLastError());
    return true;
  }

  m_pipe_handle= create_server_named_pipe(
    &mp_sa_pipe_security, global_system_variables.net_buffer_length,
    m_pipe_name.c_str(), m_pipe_path_name, sizeof(m_pipe_path_name),
    named_pipe_full_access_group);
  if (m_pipe_handle == INVALID_HANDLE_VALUE)
    return true;

  return false;
}


Channel_info* Named_pipe_listener::listen_for_connection_event()
{
  TCHAR last_error_msg[256];

  /* wait for named pipe connection */
  BOOL fConnected= ConnectNamedPipe(m_pipe_handle, &m_connect_overlapped);
  if (!fConnected && (GetLastError() == ERROR_IO_PENDING))
  {
    /*
      ERROR_IO_PENDING says async IO has started but not yet finished.
      GetOverlappedResult will wait for completion.
    */
    DWORD bytes;
    fConnected= GetOverlappedResult(m_pipe_handle, &m_connect_overlapped,
                                    &bytes, TRUE);
  }
  if (abort_loop)
    return NULL;
  if (!fConnected)
    fConnected= GetLastError() == ERROR_PIPE_CONNECTED;
  if (!fConnected)
  {
    CloseHandle(m_pipe_handle);
    mysql_rwlock_rdlock(&LOCK_named_pipe_full_access_group);
    m_pipe_handle= CreateNamedPipe(
      m_pipe_path_name, PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED | WRITE_DAC,
      PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT,
      PIPE_UNLIMITED_INSTANCES,
      (int)global_system_variables.net_buffer_length,
      (int)global_system_variables.net_buffer_length,
      NMPWAIT_USE_DEFAULT_WAIT, mp_sa_pipe_security);
    mysql_rwlock_unlock(&LOCK_named_pipe_full_access_group);
    if (m_pipe_handle == INVALID_HANDLE_VALUE)
    {
      DWORD last_error_num= GetLastError();
      FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS |
        FORMAT_MESSAGE_MAX_WIDTH_MASK,
        NULL, last_error_num,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), last_error_msg,
        sizeof(last_error_msg) / sizeof(TCHAR), NULL);
      sql_print_error("Can't create new named pipe: %s", last_error_msg);
      return NULL;
    }
    else
    {
      /* A new pipe has been successfully created, it's not connected yet so
      return NULL to spin around and wait for connection on it.
      */
      return NULL;
    }
  }
  HANDLE hConnectedPipe= m_pipe_handle;
  /* create new pipe for new connection */
  mysql_rwlock_rdlock(&LOCK_named_pipe_full_access_group);
  m_pipe_handle= CreateNamedPipe(
    m_pipe_path_name, PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED | WRITE_DAC,
    PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT, PIPE_UNLIMITED_INSTANCES,
    (int)global_system_variables.net_buffer_length,
    (int)global_system_variables.net_buffer_length, NMPWAIT_USE_DEFAULT_WAIT,
    mp_sa_pipe_security);
  mysql_rwlock_unlock(&LOCK_named_pipe_full_access_group);
  if (m_pipe_handle == INVALID_HANDLE_VALUE)
  {
    DWORD last_error_num= GetLastError();
    FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS |
      FORMAT_MESSAGE_MAX_WIDTH_MASK,
      NULL, last_error_num,
      MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), last_error_msg,
      sizeof(last_error_msg) / sizeof(TCHAR), NULL);
    sql_print_error("Can't create new named pipe: %s", last_error_msg);
    m_pipe_handle= hConnectedPipe;
    return NULL;         // We have to try again
  }

  Channel_info* channel_info= new (std::nothrow)
    Channel_info_named_pipe(hConnectedPipe);
  if (channel_info == NULL)
  {
    DisconnectNamedPipe(hConnectedPipe);
    CloseHandle(hConnectedPipe);
    return NULL;
  }
  return channel_info;
}

bool Named_pipe_listener::update_named_pipe_full_access_group(
  const char *new_group_name)
{
  SECURITY_ATTRIBUTES *p_new_sa= nullptr;
  const char *perror= nullptr;
  TCHAR last_error_msg[256];

  // Set up security attributes to provide full access to the owner
  // and minimal read/write access to others.
  if (my_security_attr_create(&p_new_sa, &perror, NAMED_PIPE_OWNER_PERMISSIONS,
    NAMED_PIPE_EVERYONE_PERMISSIONS) != 0)
  {
    sql_print_error("my_security_attr_create: %s", perror);
    return true;
  }
  if (new_group_name && new_group_name[0] != '\0')
  {
    if (my_security_attr_add_rights_to_group(
      p_new_sa, new_group_name,
      NAMED_PIPE_FULL_ACCESS_GROUP_PERMISSIONS))
    {
      sql_print_error("my_security_attr_add_rights_to_group failed for group: %s",
        new_group_name);
      return false;
    }
  }

  mp_sa_pipe_security= p_new_sa;

  // Set the DACL for the existing "listener" named pipe instance...
  if (m_pipe_handle != INVALID_HANDLE_VALUE) {
    PACL pdacl= NULL;
    BOOL dacl_present_in_descriptor= FALSE;
    BOOL dacl_defaulted= FALSE;
    if (!GetSecurityDescriptorDacl(p_new_sa->lpSecurityDescriptor,
      &dacl_present_in_descriptor, &pdacl,
      &dacl_defaulted) ||
      !dacl_present_in_descriptor)
    {
      DWORD last_error_num= GetLastError();
      FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL, last_error_num,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), last_error_msg,
        sizeof(last_error_msg) / sizeof(TCHAR), NULL);
      sql_print_error("GetSecurityDescriptorDacl failed: %s", last_error_msg);
      return true;
    }
    DWORD res =
      SetSecurityInfo(m_pipe_handle, SE_KERNEL_OBJECT,
      DACL_SECURITY_INFORMATION, NULL, NULL, pdacl, NULL);
    if (res != ERROR_SUCCESS)
    {
      char num_buff[20];
      int10_to_str(res, num_buff, 10);
      sql_print_error("SetSecurityInfo failed to update DACL on named pipe: %s", num_buff);
      return true;
    }
  }
  return false;
}

void Named_pipe_listener::close_listener()
{
  if (m_pipe_handle == INVALID_HANDLE_VALUE)
    return;

  DBUG_PRINT("quit", ("Deintializing Named_pipe_connection_acceptor"));

  /* Create connection to the handle named pipe handler to break the loop */
  HANDLE temp;
  if ((temp= CreateFile(m_pipe_path_name, NAMED_PIPE_EVERYONE_PERMISSIONS, 0,
                         NULL, OPEN_EXISTING, 0, NULL)) !=
      INVALID_HANDLE_VALUE)
  {
    WaitNamedPipe(m_pipe_path_name, 1000);
    DWORD dwMode= PIPE_READMODE_BYTE | PIPE_WAIT;
    SetNamedPipeHandleState(temp, &dwMode, NULL, NULL);
    CancelIo(temp);
    DisconnectNamedPipe(temp);
    CloseHandle(temp);
  }
  CloseHandle(m_connect_overlapped.hEvent);
  my_security_attr_free(mp_sa_pipe_security);
  mp_sa_pipe_security= nullptr;
}
