wait_pgrp.h File Reference

#include <limits.h>
#include <unistd.h>

Go to the source code of this file.

Macros
#define	WAIT_ALREADY_DEAD   INT_MIN
#define	WAIT_NONPOSITIVE_SIGNAL   (INT_MIN + 1)

Functions
void	InitWaitPgrp (void)
	Initializes WaitPgrp. More...
pid_t	ForkWithoutSigHandlers (void)
	Fork a subprocess, but do not inherit our signal handlers. More...
void	StartPgrp (void)
	Starts a new process group. More...
int	ExecvHelper (const char *path, const char *const argv[])
	Spawns a helper process. More...
int	KillPgrp (pid_t pid, int signo)
	Kills the given process group. More...
int	WaitPgrp (const char *name, pid_t *pid, int do_block, int already_killed, int *exit_status)
	Waits for the given process group to terminate, or checks its status. If the leader process died, kill the entire group. More...
int	WaitProc (const char *name, pid_t *pid, int do_block, int already_killed, int *exit_status)
	Waits for the given process to terminate, or checks its status. More...

Macro Definition Documentation

WAIT_ALREADY_DEAD

#define WAIT_ALREADY_DEAD   INT_MIN

WAIT_NONPOSITIVE_SIGNAL

#define WAIT_NONPOSITIVE_SIGNAL   (INT_MIN + 1)

Function Documentation

ExecvHelper()

int ExecvHelper	(	const char *	path,
		const char *const	argv[]
	)

Spawns a helper process.

Works just like execv(), but if path is a relative path, it looks it up within HELPER_PATH.

If it fails, it logs a message about what it tried to execute and how it failed.

ForkWithoutSigHandlers()

pid_t ForkWithoutSigHandlers

(

void

)

Fork a subprocess, but do not inherit our signal handlers.

Otherwise behaves exactly like fork().

InitWaitPgrp()

void InitWaitPgrp

(

void

)

Initializes WaitPgrp.

Actually just installs an empty SIGCHLD handler so select(), sigsuspend() etc. get interrupted by the signal.

KillPgrp()

int KillPgrp	(	pid_t	pid,
		int	signo
	)

Kills the given process group.

Parameters

pid	The process group ID.
signo	The signal to send to the process group.

Returns

Zero if and only if sending the signal succeeded.

StartPgrp()

void StartPgrp

(

void

)

Starts a new process group.

Must be called from a child process, which will become the process group leader. The process group will never die, unless killed using KillPgrp (which WaitPgrp calls implicitly when the leader process terminates).

Returns

Zero if the operation succeeded.

WaitPgrp()

int WaitPgrp	(	const char *	name,
		pid_t *	pid,
		int	do_block,
		int	already_killed,
		int *	exit_status
	)

Waits for the given process group to terminate, or checks its status. If the leader process died, kill the entire group.

Parameters

name	The name of the process group for logging.
pid	The process group ID; it is set to zero if the process group died.
do_block	Whether to wait for the process group to terminate.
already_killed	Whether the caller already sent SIGTERM to the process group. If so, we will not log this signal as that'd be spam.
exit_status	Variable that receives the exit status of the leader when it terminated. Will be negative for a signal, positive for a regular exit, or one of the WAIT_* constants.

Returns

True if the process group is still alive.

WaitProc()

int WaitProc	(	const char *	name,
		pid_t *	pid,
		int	do_block,
		int	already_killed,
		int *	exit_status
	)

Waits for the given process to terminate, or checks its status.

Parameters

name	The name of the process for logging.
pid	The process ID; it is set to zero if the process died.
do_block	Whether to wait for the process to terminate.
already_killed	Whether the caller already sent SIGTERM to the process. If so, we will not log this signal as that'd be spam.
exit_status	Variable that receives the exit status of the leader when it terminated. Will be negative for a signal, positive for a regular exit, or one of the WAIT_* constants.

Returns

True if the process is still alive.