arch/um/include/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/fixmap.h"
  10
  11 #define __under_task_size(addr, size) \
  12         (((unsigned long) (addr) < TASK_SIZE) && \
  13          (((unsigned long) (addr) + (size)) < TASK_SIZE))
  14
  15 #define __access_ok_vsyscall(type, addr, size) \
  16          ((type == VERIFY_READ) && \
  17           ((unsigned long) (addr) >= FIXADDR_USER_START) && \
  18           ((unsigned long) (addr) + (size) <= FIXADDR_USER_END) && \
  19           ((unsigned long) (addr) + (size) >= (unsigned long)(addr)))
  20
  21 #define __addr_range_nowrap(addr, size) \
  22         ((unsigned long) (addr) <= ((unsigned long) (addr) + (size)))
  23
  24 #define access_ok(type, addr, size) \
  25         (__addr_range_nowrap(addr, size) && \
  26          (__under_task_size(addr, size) || \
  27           __access_ok_vsyscall(type, addr, size) || \
  28           segment_eq(get_fs(), KERNEL_DS)))
  29
  30 extern int copy_from_user(void *to, const void __user *from, int n);
  31 extern int copy_to_user(void __user *to, const void *from, int n);
  32
  33 extern int __do_copy_to_user(void *to, const void *from, int n,
  34                              void **fault_addr, jmp_buf **fault_catcher);
  35 extern void __do_copy(void *to, const void *from, int n);
  36
  37 /*
  38  * strncpy_from_user: - Copy a NUL terminated string from userspace.
  39  * @dst:   Destination address, in kernel space.  This buffer must be at
  40  *         least @count bytes long.
  41  * @src:   Source address, in user space.
  42  * @count: Maximum number of bytes to copy, including the trailing NUL.
  43  *
  44  * Copies a NUL-terminated string from userspace to kernel space.
  45  *
  46  * On success, returns the length of the string (not including the trailing
  47  * NUL).
  48  *
  49  * If access to userspace fails, returns -EFAULT (some data may have been
  50  * copied).
  51  *
  52  * If @count is smaller than the length of the string, copies @count bytes
  53  * and returns @count.
  54  */
  55
  56 extern int strncpy_from_user(char *dst, const char __user *src, int count);
  57
  58 /*
  59  * __clear_user: - Zero a block of memory in user space, with less checking.
  60  * @to:   Destination address, in user space.
  61  * @n:    Number of bytes to zero.
  62  *
  63  * Zero a block of memory in user space.  Caller must check
  64  * the specified block with access_ok() before calling this function.
  65  *
  66  * Returns number of bytes that could not be cleared.
  67  * On success, this will be zero.
  68  */
  69 extern int __clear_user(void __user *mem, int len);
  70
  71 /*
  72  * clear_user: - Zero a block of memory in user space.
  73  * @to:   Destination address, in user space.
  74  * @n:    Number of bytes to zero.
  75  *
  76  * Zero a block of memory in user space.
  77  *
  78  * Returns number of bytes that could not be cleared.
  79  * On success, this will be zero.
  80  */
  81 extern int clear_user(void __user *mem, int len);
  82
  83 /*
  84  * strlen_user: - Get the size of a string in user space.
  85  * @str: The string to measure.
  86  * @n:   The maximum valid length
  87  *
  88  * Get the size of a NUL-terminated string in user space.
  89  *
  90  * Returns the size of the string INCLUDING the terminating NUL.
  91  * On exception, returns 0.
  92  * If the string is too long, returns a value greater than @n.
  93  */
  94 extern int strnlen_user(const void __user *str, int len);
  95
  96 #endif