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/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 extern int __do_copy_to_user(void *to, const void *from, int n,
  36                              void **fault_addr, jmp_buf **fault_catcher);
  37 extern void __do_copy(void *to, const void *from, int n);
  38
  39 /*
  40  * strncpy_from_user: - Copy a NUL terminated string from userspace.
  41  * @dst:   Destination address, in kernel space.  This buffer must be at
  42  *         least @count bytes long.
  43  * @src:   Source address, in user space.
  44  * @count: Maximum number of bytes to copy, including the trailing NUL.
  45  *
  46  * Copies a NUL-terminated string from userspace to kernel space.
  47  *
  48  * On success, returns the length of the string (not including the trailing
  49  * NUL).
  50  *
  51  * If access to userspace fails, returns -EFAULT (some data may have been
  52  * copied).
  53  *
  54  * If @count is smaller than the length of the string, copies @count bytes
  55  * and returns @count.
  56  */
  57
  58 extern int strncpy_from_user(char *dst, const char __user *src, int count);
  59
  60 /*
  61  * __clear_user: - Zero a block of memory in user space, with less checking.
  62  * @to:   Destination address, in user space.
  63  * @n:    Number of bytes to zero.
  64  *
  65  * Zero a block of memory in user space.  Caller must check
  66  * the specified block with access_ok() before calling this function.
  67  *
  68  * Returns number of bytes that could not be cleared.
  69  * On success, this will be zero.
  70  */
  71 extern int __clear_user(void __user *mem, int len);
  72
  73 /*
  74  * clear_user: - Zero a block of memory in user space.
  75  * @to:   Destination address, in user space.
  76  * @n:    Number of bytes to zero.
  77  *
  78  * Zero a block of memory in user space.
  79  *
  80  * Returns number of bytes that could not be cleared.
  81  * On success, this will be zero.
  82  */
  83 extern int clear_user(void __user *mem, int len);
  84
  85 /*
  86  * strlen_user: - Get the size of a string in user space.
  87  * @str: The string to measure.
  88  * @n:   The maximum valid length
  89  *
  90  * Get the size of a NUL-terminated string in user space.
  91  *
  92  * Returns the size of the string INCLUDING the terminating NUL.
  93  * On exception, returns 0.
  94  * If the string is too long, returns a value greater than @n.
  95  */
  96 extern int strnlen_user(const void __user *str, int len);
  97
  98 #endif