1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
96 lines
2.0 KiB
C
96 lines
2.0 KiB
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 <asm/uaccess.h>
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* copy a null terminated string from userspace
|
|
*/
|
|
long strncpy_from_user(char *dst, const char *src, long count)
|
|
{
|
|
unsigned long max;
|
|
char *p, ch;
|
|
long err = -EFAULT;
|
|
|
|
if (count < 0)
|
|
BUG();
|
|
|
|
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() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* 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 *src, long count)
|
|
{
|
|
const char *p;
|
|
long err = 0;
|
|
char ch;
|
|
|
|
if (count < 0)
|
|
BUG();
|
|
|
|
#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() */
|