/*
* Copyright (C) 2002 - 2003 Jeff Dike (jdike@addtoit.com)
* Licensed under the GPL
*/
#include "linux/compiler.h"
#include "linux/stddef.h"
#include "linux/kernel.h"
#include "linux/string.h"
#include "linux/fs.h"
#include "linux/highmem.h"
#include "asm/page.h"
#include "asm/pgtable.h"
#include "asm/uaccess.h"
#include "kern_util.h"
#include "user_util.h"
extern void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
pte_t *pte_out);
static unsigned long maybe_map(unsigned long virt, int is_write)
{
pte_t pte;
int err;
void *phys = um_virt_to_phys(current, virt, &pte);
int dummy_code;
if(IS_ERR(phys) || (is_write && !pte_write(pte))){
err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
if(err)
return(0);
phys = um_virt_to_phys(current, virt, NULL);
}
return((unsigned long) phys);
}
static int do_op(unsigned long addr, int len, int is_write,
int (*op)(unsigned long addr, int len, void *arg), void *arg)
{
struct page *page;
int n;
addr = maybe_map(addr, is_write);
if(addr == -1)
return(-1);
page = phys_to_page(addr);
addr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
n = (*op)(addr, len, arg);
kunmap(page);
return(n);
}
static void do_buffer_op(void *jmpbuf, void *arg_ptr)
{
va_list args;
unsigned long addr;
int len, is_write, size, remain, n;
int (*op)(unsigned long, int, void *);
void *arg;
int *res;
va_copy(args, *(va_list *)arg_ptr);
addr = va_arg(args, unsigned long);
len = va_arg(args, int);
is_write = va_arg(args, int);
op = va_arg(args, void *);
arg = va_arg(args, void *);
res = va_arg(args, int *);
va_end(args);
size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
remain = len;
current->thread.fault_catcher = jmpbuf;
n = do_op(addr, size, is_write, op, arg);
if(n != 0){
*res = (n < 0 ? remain : 0);
goto out;
}
addr += size;
remain -= size;
if(remain == 0){
*res = 0;
goto out;
}
while(addr < ((addr + remain) & PAGE_MASK)){
n = do_op(addr, PAGE_SIZE, is_write, op, arg);
if(n != 0){
*res = (n < 0 ? remain : 0);
goto out;
}
addr += PAGE_SIZE;
remain -= PAGE_SIZE;
}
if(remain == 0){
*res = 0;
goto out;
}
n = do_op(addr, remain, is_write, op, arg);
if(n != 0)
*res = (n < 0 ? remain : 0);
else *res = 0;
out:
current->thread.fault_catcher = NULL;
}
static int buffer_op(unsigned long addr, int len, int is_write,
int (*op)(unsigned long addr, int len, void *arg),
void *arg)
{
int faulted, res;
faulted = setjmp_wrapper(do_buffer_op, addr, len, is_write, op, arg,
&res);
if(!faulted)
return(res);
return(addr + len - (unsigned long) current->thread.fault_addr);
}
static int copy_chunk_from_user(unsigned long from, int len, void *arg)
{
unsigned long *to_ptr = arg, to = *to_ptr;
memcpy((void *) to, (void *) from, len);
*to_ptr += len;
return(0);
}
int copy_from_user_skas(void *to, const void __user *from, int n)
{
if(segment_eq(get_fs(), KERNEL_DS)){
memcpy(to, (__force void*)from, n);
return(0);
}
return(access_ok_skas(VERIFY_READ, from, n) ?
buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to):
n);
}
static int copy_chunk_to_user(unsigned long to, int len, void *arg)
{
unsigned long *from_ptr = arg, from = *from_ptr;
memcpy((void *) to, (void *) from, len);
*from_ptr += len;
return(0);
}
int copy_to_user_skas(void __user *to, const void *from, int n)
{
if(segment_eq(get_fs(), KERNEL_DS)){
memcpy((__force void*)to, from, n);
return(0);
}
return(access_ok_skas(VERIFY_WRITE, to, n) ?
buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) :
n);
}
static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
{
char **to_ptr = arg, *to = *to_ptr;
int n;
strncpy(to, (void *) from, len);
n = strnlen(to, len);
*to_ptr += n;
if(n < len)
return(1);
return(0);
}
int strncpy_from_user_skas(char *dst, const char __user *src, int count)
{
int n;
char *ptr = dst;
if(segment_eq(get_fs(), KERNEL_DS)){
strncpy(dst, (__force void*)src, count);
return(strnlen(dst, count));
}
if(!access_ok_skas(VERIFY_READ, src, 1))
return(-EFAULT);
n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
&ptr);
if(n != 0)
return(-EFAULT);
return(strnlen(dst, count));
}
static int clear_chunk(unsigned long addr, int len, void *unused)
{
memset((void *) addr, 0, len);
return(0);
}
int __clear_user_skas(void __user *mem, int len)
{
return(buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL));
}
int clear_user_skas(void __user *mem, int len)
{
if(segment_eq(get_fs(), KERNEL_DS)){
memset((__force void*)mem, 0, len);
return(0);
}
return(access_ok_skas(VERIFY_WRITE, mem, len) ?
buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len);
}
static int strnlen_chunk(unsigned long str, int len, void *arg)
{
int *len_ptr = arg, n;
n = strnlen((void *) str, len);
*len_ptr += n;
if(n < len)
return(1);
return(0);
}
int strnlen_user_skas(const void __user *str, int len)
{
int count = 0, n;
if(segment_eq(get_fs(), KERNEL_DS))
return(strnlen((__force char*)str, len) + 1);
n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
if(n == 0)
return(count + 1);
return(-EFAULT);
}
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
