wibble::sys::ChildProcess Class Reference

Fork a child process. More...

#include <childprocess.h>

Inheritance diagram for wibble::sys::ChildProcess:

Public Member Functions
	ChildProcess ()
virtual	~ChildProcess ()
void	setExec (std::string command)
	Instead of calling the main() function of this class, execute an external command.
pid_t	fork ()
	For a subprocess to run proc.
void	setupRedirects (int *stdinfd=0, int *stdoutfd=0, int *stderrfd=0)
pid_t	forkAndRedirect (int *stdinfd=0, int *stdoutfd=0, int *stderrfd=0)
pid_t	pid () const
	Get the pid of the child process or (pid_t)-1 if no child is running.
bool	running ()
int	exitStatus ()
void	waitForSuccess ()
int	wait (struct rusage *ru=0)
	Wait for the child to finish, returning its exit status and optionally storing resource usage informations in ‘ru’.
void	kill (int signal)
	Send the given signal to the process.

Protected Member Functions
virtual int	main ()=0
	Main function to be called in the child process after it has forked.
virtual void	spawnChild ()
	On Windows, it's impossible to fork(), but if you were to fork+exec, it's not all lost.
void	waitError ()
void	setupPipes ()
void	setupPrefork ()
void	setupChild ()
void	setupParent ()

Protected Attributes
pid_t	_pid
int	pipes [3][2]
int *	_stdin
int *	_stdout
int *	_stderr
int	m_status
bool	m_doExec
std::string	m_command

Detailed Description

Fork a child process.

Constructor & Destructor Documentation

ChildProcess()

wibble::sys::ChildProcess::ChildProcess ( )

inline

~ChildProcess()

virtual wibble::sys::ChildProcess::~ChildProcess ( )

inlinevirtual

Member Function Documentation

exitStatus()

int wibble::sys::ChildProcess::exitStatus

(

)

fork()

pid_t wibble::sys::ChildProcess::fork

(

)

For a subprocess to run proc.

To redirect stdio of the child process to pipes, call setupRedirects first. NB. This currently works on Windows only when setExec has been called first (any main() overrides have no effect on Windows).

Referenced by forkAndRedirect(), TestChildprocess::kill(), and wibble::sys::PipeThrough::run().

forkAndRedirect()

pid_t wibble::sys::ChildProcess::forkAndRedirect ( int *  stdinfd = 0, int *  stdoutfd = 0, int *  stderrfd = 0  )

inline

References fork(), and setupRedirects().

Referenced by TestChildprocess::inout(), TestChildprocess::output(), TestChildprocess::redirect(), and TestChildprocess::shellCommand().

kill()

void wibble::sys::ChildProcess::kill

(

int

signal

)

Send the given signal to the process.

References _pid, assert_die, and kill().

Referenced by TestChildprocess::kill(), and kill().

main()

virtual int wibble::sys::ChildProcess::main ( )

protectedpure virtual

Main function to be called in the child process after it has forked.

Implemented in EndlessChild, TestChild, and wibble::sys::Exec.

pid()

pid_t wibble::sys::ChildProcess::pid ( ) const

inline

Get the pid of the child process or (pid_t)-1 if no child is running.

Note: while ChildProcess::kill() has a safeguard against killing pid -1, if you are going to run kill on the output of pid() make sure to check what is the semanthics of kill() when pid is -1.

References _pid.

running()

bool wibble::sys::ChildProcess::running

(

)

References _pid, assert_die, m_status, and waitError().

setExec()

void wibble::sys::ChildProcess::setExec ( std::string  command )

inline

Instead of calling the main() function of this class, execute an external command.

The command is passed to the shell interpreter of the system (/bin/sh on UNIX, CreateProcess on Windows).

References m_command, and m_doExec.

setupChild()

void wibble::sys::ChildProcess::setupChild ( )

protected

References _stderr, _stdin, _stdout, pipes, and wibble::sys::renamefd().

setupParent()

void wibble::sys::ChildProcess::setupParent ( )

protected

References _stderr, _stdin, _stdout, wibble::sys::funlockfile(), and pipes.

setupPipes()

void wibble::sys::ChildProcess::setupPipes ( )

protected

setupPrefork()

void wibble::sys::ChildProcess::setupPrefork ( )

protected

References _stderr, _stdin, _stdout, and pipes.

setupRedirects()

void wibble::sys::ChildProcess::setupRedirects	(	int *	stdinfd = 0,
		int *	stdoutfd = 0,
		int *	stderrfd = 0
	)

References _stderr, _stdin, _stdout, wibble::sys::mkpipe(), and pipes.

Referenced by forkAndRedirect(), and wibble::sys::PipeThrough::run().

spawnChild()

void wibble::sys::ChildProcess::spawnChild ( )

protectedvirtual

On Windows, it's impossible to fork(), but if you were to fork+exec, it's not all lost.

You can implement spawnChild() instead of main(), which needs to call CreateProcess, spawn or similar. The redirections requested by setupRedirects are respected. Exec and ShellProcess implement spawnChild on Windows.

NB. For wait() to work, the si/pi member variables need to be filled in by the implementation.

Reimplemented in wibble::sys::Exec.

References assert_die.

wait()

int wibble::sys::ChildProcess::wait

(

struct rusage *

ru = 0

)

Wait for the child to finish, returning its exit status and optionally storing resource usage informations in ‘ru’.

Return -1 if no child is running. TODO: gracefully handle the EINTR error code

References _pid, m_status, and waitError().

Referenced by TestChildprocess::inout(), TestChildprocess::kill(), TestChildprocess::output(), TestChildprocess::redirect(), TestChildprocess::shellCommand(), and waitForSuccess().

waitError()

void wibble::sys::ChildProcess::waitError ( )

protected

Referenced by running(), and wait().

waitForSuccess()

void wibble::sys::ChildProcess::waitForSuccess

(

)

References wibble::str::fmtf(), and wait().

Member Data Documentation

_pid

pid_t wibble::sys::ChildProcess::_pid

protected

Referenced by kill(), pid(), running(), and wait().

_stderr

int * wibble::sys::ChildProcess::_stderr

protected

Referenced by setupChild(), setupParent(), setupPrefork(), and setupRedirects().

_stdin

int* wibble::sys::ChildProcess::_stdin

protected

Referenced by setupChild(), setupParent(), setupPrefork(), and setupRedirects().

_stdout

int * wibble::sys::ChildProcess::_stdout

protected

Referenced by setupChild(), setupParent(), setupPrefork(), and setupRedirects().

m_command

std::string wibble::sys::ChildProcess::m_command

protected

Referenced by setExec().

m_doExec

bool wibble::sys::ChildProcess::m_doExec

protected

Referenced by setExec().

m_status

int wibble::sys::ChildProcess::m_status

protected

Referenced by running(), and wait().

pipes

int wibble::sys::ChildProcess::pipes[3][2]

protected

Referenced by setupChild(), setupParent(), setupPrefork(), and setupRedirects().

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

• childprocess.h
• childprocess.cpp