PageAccessControlSvc Class Reference

Service to monitor access to memory pages. More...

#include <PageAccessControlSvc.h>

Inheritance diagram for PageAccessControlSvc:

Collaboration diagram for PageAccessControlSvc:

Public Member Functions
	PageAccessControlSvc (const std::string &name, ISvcLocator *pSvcLocator) ATLAS_NOT_THREAD_SAFE
	Standard GAUDI constructor.
virtual	~PageAccessControlSvc ()
	Destructor.
IPageAccessControlSvc implementation
virtual bool	startMonitoring ()
	In baseline implementation, protect pages and install a SEGV handler that counts the number of accesses to a protected address.
virtual bool	stopMonitoring ()
virtual bool	accessed (const void *address) const
	has this pointer been accessed (read/written)
virtual void	report () const
	In baseline implementation, controlled via PageAccessControlSvc.OutputLevel.
virtual bool	controlPage (const void *address)

Gaudi implementation
struct sigaction	m_saveSEGVaction
	the default action for SIGSEGV
PageAccessControl	m_accessControl
PtrAccessSEGVHandler	m_SEGVHandler
BooleanProperty	m_autoMonitor
	start on init, stop on finalize
virtual StatusCode	initialize ()
virtual StatusCode	finalize ()

Detailed Description

Service to monitor access to memory pages.

Author

Paolo Calafiura

This service uses

Definition at line 49 of file PageAccessControlSvc.h.

Constructor & Destructor Documentation

PageAccessControlSvc()

PageAccessControlSvc::PageAccessControlSvc	(	const std::string &	name,
		ISvcLocator *	pSvcLocator )

Standard GAUDI constructor.

Definition at line 8 of file PageAccessControlSvc.cxx.

                                                   : 
  base_class(name, pSvcLocator), m_saveSEGVaction(),
  m_accessControl(), m_SEGVHandler(m_accessControl)
{
  //pass m_SEGVHandler pointer to cPtrAccessSEGVHandler
  setPtrAccessSEGVHandler(&m_SEGVHandler);
  declareProperty("AutoMonitoring", m_autoMonitor=true, 
          "start monitoring on initialize, stop on finalize");
}

~PageAccessControlSvc()

virtual PageAccessControlSvc::~PageAccessControlSvc ( )

inlinevirtual

Destructor.

Definition at line 56 of file PageAccessControlSvc.h.

{} 

Member Function Documentation

accessed()

bool PageAccessControlSvc::accessed ( const void * address ) const

virtual

has this pointer been accessed (read/written)

Definition at line 36 of file PageAccessControlSvc.cxx.

                                                             {
  return m_accessControl.accessed(address);
}

controlPage()

virtual bool PageAccessControlSvc::controlPage ( const void * address )

inlinevirtual

Definition at line 70 of file PageAccessControlSvc.h.

                                                {
    return m_accessControl.forbidPage(address);
  }

finalize()

StatusCode PageAccessControlSvc::finalize ( )

virtual

Definition at line 47 of file PageAccessControlSvc.cxx.

                                          {
  StatusCode sc(StatusCode::SUCCESS);
  if (m_autoMonitor.value()) {
    if (this->stopMonitoring()) this->report();
    else sc = StatusCode::FAILURE;
  }
  return sc;
}

initialize()

StatusCode PageAccessControlSvc::initialize ( )

virtual

Definition at line 40 of file PageAccessControlSvc.cxx.

                                            {
  StatusCode sc(StatusCode::SUCCESS);
  msg(MSG::INFO) << "Initializing " << name() << endmsg ;
  if (m_autoMonitor.value() && !this->startMonitoring()) sc = StatusCode::FAILURE;
  return sc;
}

report()

void PageAccessControlSvc::report ( ) const

virtual

In baseline implementation, controlled via PageAccessControlSvc.OutputLevel.

Definition at line 56 of file PageAccessControlSvc.cxx.

                                        {
  msg(MSG::INFO) << "Access monitoring report" << endmsg;
  PtrAccessSEGVHandler::const_iterator i(m_SEGVHandler.beginAccessedPtrs()),
    e(m_SEGVHandler.endAccessedPtrs());
  while (i != e) {
    msg(MSG::DEBUG) << "accessed pointer at @" << std::hex << *i++ << endmsg; 
  }
  PageAccessControl::const_iterator ia(m_accessControl.beginProtectedPtrs()),
    ea(m_accessControl.endProtectedPtrs());
  while (ia != ea) {
    msg(MSG::DEBUG) << "protected page at @" << std::hex << ia->addr
            << " accessed "<< ia->restored << " times" << endmsg; 
    ++ia;
  }
}

startMonitoring()

bool PageAccessControlSvc::startMonitoring ( )

virtual

In baseline implementation, protect pages and install a SEGV handler that counts the number of accesses to a protected address.

Definition at line 19 of file PageAccessControlSvc.cxx.

                                            {
  int rc = sigaction(SIGSEGV,nullptr, &m_saveSEGVaction);
  if (0==rc) {
    struct sigaction sa(m_saveSEGVaction);
    sa.sa_sigaction= cPtrAccessSEGVHandler; 
    sa.sa_flags=SA_SIGINFO;
    //off we go
    rc=sigaction(SIGSEGV,&sa,nullptr);
  }
  return (0==rc);
}

stopMonitoring()

bool PageAccessControlSvc::stopMonitoring ( )

virtual

Definition at line 31 of file PageAccessControlSvc.cxx.

                                           {
  return (0 == sigaction(SIGSEGV,&m_saveSEGVaction, nullptr));
}

Member Data Documentation

m_accessControl

PageAccessControl PageAccessControlSvc::m_accessControl

private

Definition at line 86 of file PageAccessControlSvc.h.

m_autoMonitor

BooleanProperty PageAccessControlSvc::m_autoMonitor

private

start on init, stop on finalize

Definition at line 88 of file PageAccessControlSvc.h.

m_saveSEGVaction

struct sigaction PageAccessControlSvc::m_saveSEGVaction

private

the default action for SIGSEGV

Definition at line 85 of file PageAccessControlSvc.h.

m_SEGVHandler

PtrAccessSEGVHandler PageAccessControlSvc::m_SEGVHandler

private

Definition at line 87 of file PageAccessControlSvc.h.

---

The documentation for this class was generated from the following files:

• PageAccessControlSvc.h
• PageAccessControlSvc.cxx