[mirror_ubuntu-zesty-kernel.git] / arch / frv / kernel / uaccess.c

/* uaccess.c: userspace access functions
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/mm.h>
#include <linux/module.h>
#include <asm/uaccess.h>

/*****************************************************************************/
/*
 * copy a null terminated string from userspace
 */
long strncpy_from_user(char *dst, const char __user *src, long count)
{
	unsigned long max;
	char *p, ch;
	long err = -EFAULT;

	BUG_ON(count < 0);

	p = dst;

#ifndef CONFIG_MMU
	if ((unsigned long) src < memory_start)
		goto error;
#endif

	if ((unsigned long) src >= get_addr_limit())
		goto error;

	max = get_addr_limit() - (unsigned long) src;
	if ((unsigned long) count > max) {
		memset(dst + max, 0, count - max);
		count = max;
	}

	err = 0;
	for (; count > 0; count--, p++, src++) {
		__get_user_asm(err, ch, src, "ub", "=r");
		if (err < 0)
			goto error;
		if (!ch)
			break;
		*p = ch;
	}

	err = p - dst; /* return length excluding NUL */

 error:
	if (count > 0)
		memset(p, 0, count); /* clear remainder of buffer [security] */

	return err;

} /* end strncpy_from_user() */

EXPORT_SYMBOL(strncpy_from_user);

/*****************************************************************************/
/*
 * Return the size of a string (including the ending 0)
 *
 * Return 0 on exception, a value greater than N if too long
 */
long strnlen_user(const char __user *src, long count)
{
	const char __user *p;
	long err = 0;
	char ch;

	BUG_ON(count < 0);

#ifndef CONFIG_MMU
	if ((unsigned long) src < memory_start)
		return 0;
#endif

	if ((unsigned long) src >= get_addr_limit())
		return 0;

	for (p = src; count > 0; count--, p++) {
		__get_user_asm(err, ch, p, "ub", "=r");
		if (err < 0)
			return 0;
		if (!ch)
			break;
	}

	return p - src + 1; /* return length including NUL */

} /* end strnlen_user() */

EXPORT_SYMBOL(strnlen_user);
Commit	Line	Data
1da177e4 LT	1	/* uaccess.c: userspace access functions
	2	*
	3	* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/mm.h>
40234401	13	#include <linux/module.h>
1da177e4 LT	14	#include <asm/uaccess.h>
	15
	16	/*****************************************************************************/
	17	/*
	18	* copy a null terminated string from userspace
	19	*/
a8a77573	20	long strncpy_from_user(char dst, const char __user src, long count)
1da177e4 LT	21	{
	22	unsigned long max;
	23	char *p, ch;
	24	long err = -EFAULT;
	25
db5c444e	26	BUG_ON(count < 0);
1da177e4 LT	27
	28	p = dst;
	29
	30	#ifndef CONFIG_MMU
	31	if ((unsigned long) src < memory_start)
	32	goto error;
	33	#endif
	34
	35	if ((unsigned long) src >= get_addr_limit())
	36	goto error;
	37
	38	max = get_addr_limit() - (unsigned long) src;
	39	if ((unsigned long) count > max) {
	40	memset(dst + max, 0, count - max);
	41	count = max;
	42	}
	43
	44	err = 0;
	45	for (; count > 0; count--, p++, src++) {
	46	__get_user_asm(err, ch, src, "ub", "=r");
	47	if (err < 0)
	48	goto error;
	49	if (!ch)
	50	break;
	51	*p = ch;
	52	}
	53
	54	err = p - dst; /* return length excluding NUL */
	55
	56	error:
	57	if (count > 0)
	58	memset(p, 0, count); /* clear remainder of buffer [security] */
	59
	60	return err;
40234401	61
1da177e4 LT	62	} /* end strncpy_from_user() */
1da177e4 LT	63
40234401 DH	64	EXPORT_SYMBOL(strncpy_from_user);
40234401 DH	65
1da177e4 LT	66	/*****************************************************************************/
	67	/*
	68	* Return the size of a string (including the ending 0)
	69	*
	70	* Return 0 on exception, a value greater than N if too long
	71	*/
a8a77573	72	long strnlen_user(const char __user *src, long count)
1da177e4	73	{
a8a77573	74	const char __user *p;
1da177e4 LT	75	long err = 0;
	76	char ch;
	77
db5c444e	78	BUG_ON(count < 0);
1da177e4 LT	79
	80	#ifndef CONFIG_MMU
	81	if ((unsigned long) src < memory_start)
	82	return 0;
	83	#endif
	84
	85	if ((unsigned long) src >= get_addr_limit())
	86	return 0;
	87
	88	for (p = src; count > 0; count--, p++) {
	89	__get_user_asm(err, ch, p, "ub", "=r");
	90	if (err < 0)
	91	return 0;
	92	if (!ch)
	93	break;
	94	}
	95
	96	return p - src + 1; /* return length including NUL */
40234401	97
1da177e4	98	} /* end strnlen_user() */
40234401 DH	99
40234401 DH	100	EXPORT_SYMBOL(strnlen_user);