arch/um/include/shared/um_uaccess.h

   1 /*
   2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #ifndef __ARCH_UM_UACCESS_H
   7 #define __ARCH_UM_UACCESS_H
   8
   9 #include <asm/elf.h>
  10 #include <asm/fixmap.h>
  11 #include "sysdep/archsetjmp.h"
  12
  13 #define __under_task_size(addr, size) \
  14         (((unsigned long) (addr) < TASK_SIZE) && \
  15          (((unsigned long) (addr) + (size)) < TASK_SIZE))
  16
  17 #define __access_ok_vsyscall(type, addr, size) \
  18          ((type == VERIFY_READ) && \
  19           ((unsigned long) (addr) >= FIXADDR_USER_START) && \
  20           ((unsigned long) (addr) + (size) <= FIXADDR_USER_END) && \
  21           ((unsigned long) (addr) + (size) >= (unsigned long)(addr)))
  22
  23 #define __addr_range_nowrap(addr, size) \
  24         ((unsigned long) (addr) <= ((unsigned long) (addr) + (size)))
  25
  26 #define access_ok(type, addr, size) \
  27         (__addr_range_nowrap(addr, size) && \
  28          (__under_task_size(addr, size) || \
  29           __access_ok_vsyscall(type, addr, size) || \
  30           segment_eq(get_fs(), KERNEL_DS)))
  31
  32 extern int copy_from_user(void *to, const void __user *from, int n);
  33 extern int copy_to_user(void __user *to, const void *from, int n);
  34
  35 /*
  36  * strncpy_from_user: - Copy a NUL terminated string from userspace.
  37  * @dst:   Destination address, in kernel space.  This buffer must be at
  38  *         least @count bytes long.
  39  * @src:   Source address, in user space.
  40  * @count: Maximum number of bytes to copy, including the trailing NUL.
  41  *
  42  * Copies a NUL-terminated string from userspace to kernel space.
  43  *
  44  * On success, returns the length of the string (not including the trailing
  45  * NUL).
  46  *
  47  * If access to userspace fails, returns -EFAULT (some data may have been
  48  * copied).
  49  *
  50  * If @count is smaller than the length of the string, copies @count bytes
  51  * and returns @count.
  52  */
  53
  54 extern int strncpy_from_user(char *dst, const char __user *src, int count);
  55
  56 /*
  57  * __clear_user: - Zero a block of memory in user space, with less checking.
  58  * @to:   Destination address, in user space.
  59  * @n:    Number of bytes to zero.
  60  *
  61  * Zero a block of memory in user space.  Caller must check
  62  * the specified block with access_ok() before calling this function.
  63  *
  64  * Returns number of bytes that could not be cleared.
  65  * On success, this will be zero.
  66  */
  67 extern int __clear_user(void __user *mem, int len);
  68
  69 /*
  70  * clear_user: - Zero a block of memory in user space.
  71  * @to:   Destination address, in user space.
  72  * @n:    Number of bytes to zero.
  73  *
  74  * Zero a block of memory in user space.
  75  *
  76  * Returns number of bytes that could not be cleared.
  77  * On success, this will be zero.
  78  */
  79 extern int clear_user(void __user *mem, int len);
  80
  81 /*
  82  * strlen_user: - Get the size of a string in user space.
  83  * @str: The string to measure.
  84  * @n:   The maximum valid length
  85  *
  86  * Get the size of a NUL-terminated string in user space.
  87  *
  88  * Returns the size of the string INCLUDING the terminating NUL.
  89  * On exception, returns 0.
  90  * If the string is too long, returns a value greater than @n.
  91  */
  92 extern int strnlen_user(const void __user *str, int len);
  93
  94 #endif