linux-user/uaccess.c

   1 /* User memory access */
   2 #include <stdio.h>
   3 #include <string.h>
   4
   5 #include "qemu.h"
   6
   7 /* copy_from_user() and copy_to_user() are usually used to copy data
   8  * buffers between the target and host.  These internally perform
   9  * locking/unlocking of the memory.
  10  */
  11 abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len)
  12 {
  13     abi_long ret = 0;
  14     void *ghptr;
  15
  16     if ((ghptr = lock_user(VERIFY_READ, gaddr, len, 1))) {
  17         memcpy(hptr, ghptr, len);
  18         unlock_user(ghptr, gaddr, 0);
  19     } else
  20         ret = -TARGET_EFAULT;
  21
  22     return ret;
  23 }
  24
  25
  26 abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len)
  27 {
  28     abi_long ret = 0;
  29     void *ghptr;
  30
  31     if ((ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0))) {
  32         memcpy(ghptr, hptr, len);
  33         unlock_user(ghptr, gaddr, len);
  34     } else
  35         ret = -TARGET_EFAULT;
  36
  37     return ret;
  38 }
  39
  40
  41 /* Return the length of a string in target memory.  */
  42 /* FIXME - this doesn't check access_ok() - it's rather complicated to
  43  * do it correctly because we need to check the bytes in a page and then
  44  * skip to the next page and check the bytes there until we find the
  45  * terminator.  There should be a general function to do this that
  46  * can look for any byte terminator in a buffer - not strlen().
  47  */
  48 abi_long target_strlen(abi_ulong gaddr)
  49 {
  50     return strlen(g2h(gaddr));
  51 }