QProcessStatus Class Reference

List of all members.

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Detailed Description

apollo process status and signal handler

Author:

Marco Pallavicini

sergio.didomizio@ge.infn.it

update process status according to received signal

Handled signals are: SIGINT, SIGABRT, SIGFPE, SIGSEGV, SIGTERM, SIGUSR1, SIGUSR2, SIGTTIN, SIGTTOU. Each signal can be associated to a value of ProcessStatus_t. More than one signal can be associated to the same process status. Several signals are enabled by default and serveral are not. Moreover, the association between a signal and the corresponding ProcessStatus_t is not modifiable for all signals, as for the enabled/disabled state, which can be toggled only for several signals. When a signal is not enabled, the default signal handler is called. In order for a signal to be ignored, the Ignore() method must be called with the signal as argument. All signals that can be disabled can be also ignored. Follows a detailed list of the possibilities the user has to control each signal:

• SIGFPE, SIGSEGV: these two signals are associated to the QError_s state. They are enabled and cannot be disabled, nor the associated status can be changed.
• SIGUSR1: this signal is enabled by default and is associated to the QRunning_s status. This signal can be disabled, but the associated status cannot be changed.
• SIGTERM: this signal is enabled by default and is associated to the QStopped_s status. This signal can be disabled, but the associated status cannot be changed.
• SIGABRT: this signal is enabled by default and is associated to the QExiting_s status. This signal can be disabled, but the associated status cannot be changed.
• SIGUSR2: this signal is disabled by default and is associated to the special state QAskStatus_s, used to inform MsgServer about current process status. This signal don't change the current process status. The action associated to this signal cannot be modified.
• SIGINT, SIGTTIN, SIGTTOU: these three signals are disabled by default, and there is no status associated to them. Unless they are explicitly enabled by the user, the system default signal handler will be called when these signals are caught.

Public Member Functions
virtual	~QProcessStatus ()
	dtor
bool	Associate (int signalId, ProcessStatus_t pStatus)
	associate a signal to a given process status
bool	Enable (int signalId)
	associate signal to cuore signal handler
bool	Disable (int signalId)
	enable handling of a signal
bool	Ignore (int signalId)
	ignore signal
bool	HasChanged () const
	tell wehter process status has changed
volatile ProcessStatus_t	GetState () const
	get current state
volatile ProcessStatus_t	GetPreviousState () const
	get previous state
volatile ProcessStatus_t	GetNextState () const
	get the status the process will go into the next time that Notify() will be called. Returns current state if hasChanged() returns false
void	SetState (ProcessStatus_t state)
	change current process status bypassing status queue vector
void	Notify ()
	acknowledge oldest process status contained in staus queue vector
volatile bool	isRunning () const
	check wether current process status is QRunning_s
volatile bool	isPaused () const
	check wether current process status is QPaused_s
volatile bool	isIdle () const
	check wether current process status is QIdle_s
volatile bool	isReady () const
	check wether current process status is QReady_s
volatile bool	TrgCtrlEnabled () const
	check wether trigger control signals are enabled
const std::string &	GetError () const
	get error string
void	SetError (const std::string &errMsg)
	set error string
bool	isError () const
	check wether an error occurred
void	SetTrgCtrlEnabled (bool enabled)
	enable or disable trigger status control
void	InformServer ()
	inform Daq Server about current process status
void	SetName (const std::string &name)
	set process name that will be used for communication with message logger server
Static Public Member Functions
static QProcessStatus &	GetInstance ()
	get singleton Instance
Private Member Functions
	QProcessStatus ()
	declare signal handler for handled signals, set error string to an empty string and disable by default trigger control signals
void	HandleSignal (int signalId)
	this method is called each time a registered signal is caught. It updates the status queue and inform message logger if necessary.
void	AssociateDefaults ()
	associate default signals to be caught
void	AddToQueue (ProcessStatus_t state)
	add state to process status queue.
ProcessStatus_t	GetLastStatus () const
	get last status that have been added to status queue. If queue is empty current process status is returned.
bool	CanBeHandled (int signalId) const
	check wether requested signal can be handled
bool	CanBeDisabled (int signalId) const
	check wether requested signal can be disabled
Private Attributes
ProcessStatus_t	fState
	current process status
ProcessStatus_t	fPreviousState
	previous process status
bool	fTrgCtrl
	determine wether trigger control signals are enabled (default is disabled)
bool	fInformEnabled
	determine wether to inform server about changes of state
const size_t	kMaxQueued
	maximum number of not-notified process statuses. If process queue exceeds this size a warning is sent to stderr.
std::deque< ProcessStatus_t >	fStatusQueue
	vector containing stauts evolution for current process contains all status changes that are newer than current state
std::string	fError
	error string
std::map< int, ProcessStatus_t >	fSigMap
	map of system signal and associated process status
Friends
void	SigHandler (int)
	signal handler function

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Member Function Documentation

bool QProcessStatus::Associate	(	int	signalId,
		ProcessStatus_t	pStatus
	)

associate a signal to a given process status

Parameters:

	signalId	system signal to be associated to status pStatus
	pStatus	process status to be associated to signal signalId

Returns:

true if association succeeded, false otherwise

See the documentation at the beginning of this class to understand what signal can be associated to which status

bool QProcessStatus::Enable

(

int

signalId

)

associate signal to cuore signal handler

Parameters:

signalId

signal to be enabled. This signal must be already associated to a value of ProcessStatus_t.

Returns:

true unless

void QProcessStatus::SetState

(

ProcessStatus_t

state

)

change current process status bypassing status queue vector

Parameters:

state

new process status

Previous state is updated, status queue is flushed and InformServer() is called

volatile bool QProcessStatus::isRunning

(

)

const [inline]

check wether current process status is QRunning_s

Returns:

true if current status is QRunning_s, false otherwise

volatile bool QProcessStatus::isPaused

(

)

const [inline]

check wether current process status is QPaused_s

Returns:

true if current status is QPaused_s, false otherwise

volatile bool QProcessStatus::isIdle

(

)

const [inline]

check wether current process status is QIdle_s

Returns:

true if current status is QIdle_s, false otherwise

volatile bool QProcessStatus::isReady

(

)

const [inline]

check wether current process status is QReady_s

Returns:

true if current status is QReady_s, false otherwise

volatile bool QProcessStatus::TrgCtrlEnabled

(

)

const [inline]

check wether trigger control signals are enabled

Returns:

true if trigger control signals are enabled, false otherwise

const std::string& QProcessStatus::GetError

(

)

const [inline]

get error string

Returns:

error string associated to last error, or empty string if no error occurred

void QProcessStatus::SetError

(

const std::string &

errMsg

)

[inline]

set error string

Parameters:

errMsg

error message

void QProcessStatus::SetTrgCtrlEnabled

(

bool

enabled

)

[inline]

enable or disable trigger status control

Parameters:

enable

if true, trigger control is enabled (default is disabled)

void QProcessStatus::InformServer

(

)

inform Daq Server about current process status

Msg Server is informed by mean of a socket client. If error string is not empty, it is sent to Daq Server together with process status Id.

void QProcessStatus::SetName

(

const std::string &

name

)

[inline]

set process name that will be used for communication with message logger server

Parameters:

name

process name

void QProcessStatus::HandleSignal

(

int

signalId

)

[private]

this method is called each time a registered signal is caught. It updates the status queue and inform message logger if necessary.

Parameters:

signalId

system signal to be handled

Add status associated to signal signalId to process status queue. If signal is SIGSEGV or SIGFPE and process queue already contains another error, exit is forced calling exit(1). Detected signal is added to queue only if it is consistent with last status that is in queue (or with current status in case queue is empty). In case of inconistent state, an error is set by mean of SetError(). For example stop signal is not considered if process is not running.

void QProcessStatus::AddToQueue

(

ProcessStatus_t

state

)

[private]

add state to process status queue.

Parameters:

state

status to be added to queue

If state is QTriggerOn_s or QTriggerOff_s, the queue is populated with 2 new elements: the requested state and then the current one. If process queue has more than kMaxQueued elements a warning is sent to stderr.

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Friends And Related Function Documentation

void SigHandler

(

int

)

[friend]

signal handler function

Parameters:

signalId

signal to be handled

When a registered system signal is detected, this function simply calls the QProcessStatus::HandleSignal() method.

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

• /usr/local/cuore/pkg/apollosignals/QProcessStatus.hh
• /usr/local/cuore/pkg/apollosignals/QProcessStatus.cc

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