/* 
 * Spawn services built on fork() for those libc's that lack spawning.
 * $Id$
 * Copyright (c) 1997 by Tycho Softworks.
 * For conditions of distribution and reuse see product license.
 */

#include <proc/process.h>
#include <std/files.h>

static	void	spawn_redirect(int io, int mode)
{
	int	fd = open("/dev/null", mode);

	if(fd < 0)
		exit(EX_OSFILE);

	if(fd != io)
	{
		dup2(fd, io);
		close(fd);
	}
}

static	int	spawn_wait(pid_t pid, int mode)
{
	int	waitflag = mode & P_WAIT;

	/* -1 on fork failure */

	if(pid == -1)
		return -1;

	if(!waitflag)
		return pid;		

	waitpid(pid, &waitflag, 0);
	return WEXITSTATUS(waitflag);
}		
	
static	void	spawn_mode(int mode)
{
	int	i;

	if(mode & P_BACKGROUND)
	{
		spawn_redirect(0, O_RDONLY);
		spawn_redirect(1, O_WRONLY);
		spawn_redirect(2, O_WRONLY);
	}

	for(i = 3; i < OPEN_MAX; ++i)
		close(i);

	if(mode & P_SESSION)
		setsid();
}

int	spawnv(const int mode, const char *path, char *const argv[])
{
	pid_t pid = 0;
	int	status;

	if(!(mode & P_OVERLAY))
		pid = fork();

	if(pid)
		return spawn_wait(pid, mode);
	
	spawn_mode(mode);
	execv(path, argv);
	exit(EX_UNAVAILABLE);
	return -1;
}

int	spawnvp(const int mode, const char *path, char *const argv[])   
{
	pid_t pid = 0;
	int	status;

	if(!(mode & P_OVERLAY))
		pid = fork();

	if(pid)
		return spawn_wait(pid, mode); 

	spawn_mode(mode);
	execvp(path, argv);
	exit(EX_UNAVAILABLE);
	return -1;
}