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// $Id: RtclSignalAction.cpp 631 2015-01-09 21:36:51Z mueller $

//

// Copyright 2013-2014 by Walter F.J. Mueller <W.F.J.Mueller@gsi.de>

//

// This program is free software; you may redistribute and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation, either version 2, or at your option any later version.

//

// 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

// for complete details.

// 

// Revision History: 

// Date         Rev Version  Comment

// 2014-11-08   602   1.0.3  cast int first to ptrdiff_t, than to ClientData

// 2014-08-22   584   1.0.2  use nullptr

// 2014-08-02   577   1.0.1  add include unistd.h  (write+pipe dcl)

// 2013-05-17   521   1.0    Initial version

// ---------------------------------------------------------------------------

/*!

  \file

  \version $Id: RtclSignalAction.cpp 631 2015-01-09 21:36:51Z mueller $

  \brief   Implemenation of class RtclSignalAction.

 */

#include <errno.h>

#include <signal.h>

#include <string.h>

#include <unistd.h>

#include <iostream>

#include "librtools/Rexception.hpp"

#include "RtclSignalAction.hpp"

using namespace std;

/*!

  \class Retro::RtclSignalAction

  \brief FIXME_docs

*/

// all method definitions in namespace Retro

namespace Retro {

RtclSignalAction* RtclSignalAction::fpObj = nullptr;

//------------------------------------------+-----------------------------------

//! FIXME_docs

bool RtclSignalAction::Init(Tcl_Interp* interp, RerrMsg& emsg)

{

  if (fpObj) {

    emsg.Init("RtclSignalAction::Init", "already initialized");

    return false;

  }

  try {

    fpObj = new RtclSignalAction(interp);

  } catch (exception& e) {

    emsg.Init("RtclSignalAction::Init", string("exception: ")+e.what());

    return false;

  }

  Tcl_CreateExitHandler((Tcl_ExitProc*) ThunkTclExitProc, (ClientData) fpObj);

  return true;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

RtclSignalAction* RtclSignalAction::Obj()

{

  return fpObj;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

bool RtclSignalAction::SetAction(int signum, Tcl_Obj* pobj, RerrMsg& emsg)

{

  if (!ValidSignal(signum, emsg)) return false;

  if (fActionSet[signum] && !ClearAction(signum, emsg)) return false;

  struct sigaction sigact;

  ::memset(&sigact, 0, sizeof(sigact));

  sigact.sa_handler = SignalHandler;

  if (::sigaction(signum, &sigact, &fOldAction[signum]) != 0) {

    emsg.InitErrno("RtclSignalAction::SetAction",

                   "sigaction() failed: ", errno);

    return false;

  }

  fpScript[signum] = pobj;

  fActionSet[signum] = true;

  return true;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

bool RtclSignalAction::GetAction(int signum, Tcl_Obj*& pobj, RerrMsg& emsg)

{

  if (!ValidSignal(signum, emsg)) return false;

  if (!fActionSet[signum]) {

    emsg.Init("RtclSignalAction::GetAction", "no action for signal");

    return false;

  }

  pobj = fpScript[signum];

  return true;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

bool RtclSignalAction::ClearAction(int signum, RerrMsg& emsg)

{

  if (!ValidSignal(signum, emsg)) return false;

  if (!fActionSet[signum]) {

    emsg.Init("RtclSignalAction::ClearAction", "no action for signal");

    return false;

  }

  if (::sigaction(signum, &fOldAction[signum], nullptr) != 0) {

    emsg.InitErrno("RtclSignalAction::ClearAction",

                   "sigaction() failed: ", errno);

    return false;

  }

  fpScript[signum] = nullptr;

  fActionSet[signum] = false;

  return true;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

bool RtclSignalAction::ValidSignal(int signum, RerrMsg& emsg)

{

  if (signum > 0 && signum < 32) {

    switch (signum) {

    case SIGHUP:

    case SIGINT:

    case SIGTERM:

    case SIGUSR1:

    case SIGUSR2:

      return true;

    default:

      break;

    }

  }

  emsg.Init("RtclSignalAction::ValidSignal", "unsupported signal");

  return false;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void RtclSignalAction::TclChannelHandler(int mask)

{

  char signum;

  Tcl_Read(fShuttleChn, (char*) &signum, sizeof(signum));

  // FIXME_code: handle return code

  Tcl_SetVar2Ex(fpInterp, "Rutil_signum", nullptr,

                Tcl_NewIntObj((int)signum), 0);

  // FIXME_code: handle return code

  if ((Tcl_Obj*)fpScript[(int)signum]) {

    Tcl_EvalObjEx(fpInterp, fpScript[(int)signum], TCL_EVAL_GLOBAL);

    // FIXME_code: handle return code 

  }

  return;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void RtclSignalAction::SignalHandler(int signum)

{

  if (fpObj && fpObj->fFdPipeWrite>0) {

    char signum_c = signum;

    int irc = ::write(fpObj->fFdPipeWrite, (void*) &signum_c, sizeof(signum_c));

    if (irc < 0)

      cerr << "RtclSignalAction::SignalHandler-E: write() failed, errno="

           << errno << endl;

  } else {

    cerr << "RtclSignalAction::SignalHandler-E: spurious call" << endl;

  }

  return;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void RtclSignalAction::ThunkTclChannelHandler(ClientData cdata, int mask)

{

  if (fpObj) fpObj->TclChannelHandler(mask);

  return;

}

//------------------------------------------+-----------------------------------

//! FIXME_docs

void RtclSignalAction::ThunkTclExitProc(ClientData cdata)

{

  delete fpObj;

  fpObj = nullptr;

  return;

}

//------------------------------------------+-----------------------------------

//! constructor

RtclSignalAction::RtclSignalAction(Tcl_Interp* interp)

  : fpInterp(interp),

    fFdPipeRead(-1),

    fFdPipeWrite(-1),

    fShuttleChn(),

    fActionSet(),

    fpScript(),

    fOldAction()

{

  for (size_t i=0; i<32; i++) {

    fActionSet[i] = false;

    ::memset(&fOldAction[i], 0, sizeof(fOldAction[0]));

  }

  int pipefd[2];

  if (::pipe(pipefd) < 0)

    throw Rexception("RtclSignalAction::<ctor>", "pipe() failed: ", errno);

  fFdPipeRead  = pipefd[0];

  fFdPipeWrite = pipefd[1];

  // cast first to ptrdiff_t to promote to proper int size

  fShuttleChn = Tcl_MakeFileChannel((ClientData)(ptrdiff_t)fFdPipeRead,

                                    TCL_READABLE);

  Tcl_SetChannelOption(nullptr, fShuttleChn, "-buffersize", "64");

  Tcl_SetChannelOption(nullptr, fShuttleChn, "-encoding", "binary");

  Tcl_SetChannelOption(nullptr, fShuttleChn, "-translation", "binary");

  Tcl_CreateChannelHandler(fShuttleChn, TCL_READABLE,

                           (Tcl_FileProc*) ThunkTclChannelHandler,

                           (ClientData) this);

}

//------------------------------------------+-----------------------------------

//! Destructor

RtclSignalAction::~RtclSignalAction()

{

  for (size_t i=0; i<32; i++) {

    RerrMsg emsg;

    if (fActionSet[i]) ClearAction(i, emsg);

  }

}

} // end namespace Retro