wstrncpy.c

该项目主要是将wingdows程序直接运行在linux上

/*
 * wstrncpy.c
 *
 * Copyright (C) 2006  Insigme Co., Ltd
 *
 * Authors: 
 * - Lixing Chu
 *
 * This software has been developed while working on the Linux Unified Kernel
 * project (http://linux.insigma.com.cn) in the Insigma Reaserch Institute,  
 * which is a subdivision of Insigma Co., Ltd (http://www.insigma.com.cn).
 * 
 * The project is sponsored by Insigma Co., Ltd.
 *
 * The authors can be reached at [e-mail].
 *
 * 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.
 *
 * Revision History:
 *   Jan 2006 - Created.
 */
 
/* 
 * wstrncpy.c: copy wchar string
 * Reference to Linux kernel code
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/nls.h>
#include <linux/errno.h>
#include <asm/uaccess.h>

#ifdef CONFIG_UNIFIED_KERNEL

/*
 * Copy a null terminated wide string from userspace.
 */

#define __do_wstrncpy_from_user(dst,src,count,res)			   \
do {									   \
	int __d0, __d1, __d2;						   \
	__asm__ __volatile__(						   \
		"	testl %1,%1\n"					   \
		"	jz 2f\n"					   \
		"0:	lodsw\n"					   \
		"	stosw\n"					   \
		"	testw %%ax,%%ax\n"				   \
		"	jz 1f\n"					   \
		"	decl %1\n"					   \
		"	jnz 0b\n"					   \
		"1:	subl %1,%0\n"					   \
		"2:\n"							   \
		".section .fixup,\"ax\"\n"				   \
		"3:	movl %5,%0\n"					   \
		"	jmp 2b\n"					   \
		".previous\n"						   \
		".section __ex_table,\"a\"\n"				   \
		"	.align 4\n"					   \
		"	.long 0b,3b\n"					   \
		".previous"						   \
		: "=d"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1),	   \
		  "=&D" (__d2)						   \
		: "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
		: "memory");						   \
} while (0)
/*
long __wstrncpy_from_user(wchar_t *dst, const wchar_t *src, long count)
{
	long res;
	__do_wstrncpy_from_user(dst, src, count, res);
	return res;
}
*/
/*
 * copy a wide string into kernel-space
 */
long wstrncpy_from_user(wchar_t *dst, const wchar_t *src, long count)
{
	long res = -EFAULT;
	if (access_ok(VERIFY_READ, src, 2))
		__do_wstrncpy_from_user(dst, src, count, res);
	return res;
} /* end wcsncpy_from_user() */

/*
 * return the size of a wide string (including the ending NUL)
 * - return 0 on exception, a value greater than N if too long
 */
long wstrnlen_user(const wchar_t *s, long n)
{
	unsigned long mask = -__addr_ok(s);
	unsigned long res, tmp;

	__asm__ __volatile__(
		"	andl %0,%%ecx\n"
		"0:	repne; scasw\n"
		"	setne %%al\n"
		"	subl %%ecx,%0\n"
		"	addl %0,%%eax\n"
		"1:\n"
		".section .fixup,\"ax\"\n"
		"2:	xorl %%eax,%%eax\n"
		"	jmp 1b\n"
		".previous\n"
		".section __ex_table,\"a\"\n"
		"	.align 4\n"
		"	.long 0b,2b\n"
		".previous"
		:"=r" (n), "=D" (s), "=a" (res), "=c" (tmp)
		:"0" (n), "1" (s), "2" (0), "3" (mask)
		:"cc");
	return res & mask;
} /* end wcsnlen_user() */
#endif