Merge branch 'for-upstream' of git://repo.or.cz/qemu/agraf
[qemu.git] / 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 /* Return the length of a string in target memory or -TARGET_EFAULT if
41 access error */
42 abi_long target_strlen(abi_ulong guest_addr1)
43 {
44 uint8_t *ptr;
45 abi_ulong guest_addr;
46 int max_len, len;
47
48 guest_addr = guest_addr1;
49 for(;;) {
50 max_len = TARGET_PAGE_SIZE - (guest_addr & ~TARGET_PAGE_MASK);
51 ptr = lock_user(VERIFY_READ, guest_addr, max_len, 1);
52 if (!ptr)
53 return -TARGET_EFAULT;
54 len = qemu_strnlen((const char *)ptr, max_len);
55 unlock_user(ptr, guest_addr, 0);
56 guest_addr += len;
57 /* we don't allow wrapping or integer overflow */
58 if (guest_addr == 0 ||
59 (guest_addr - guest_addr1) > 0x7fffffff)
60 return -TARGET_EFAULT;
61 if (len != max_len)
62 break;
63 }
64 return guest_addr - guest_addr1;
65 }