busybox/libbb/device_open.c

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"

/* try to open up the specified device */
int device_open(const char *device, int mode)
{
	int m, f, fd;

	m = mode | O_NONBLOCK;

	/* Retry up to 5 times */
	/* TODO: explain why it can't be considered insane */
	for (f = 0; f < 5; f++) {
		fd = open(device, m, 0600);
		if (fd >= 0)
			break;
	}
	if (fd < 0)
		return fd;
	/* Reset original flags. */
	if (m != mode)
		fcntl(fd, F_SETFL, mode);
	return fd;
}