Merge remote-tracking branch 'remotes/ehabkost-gl/tags/x86-next-pull-request' into...
[qemu.git] / linux-user / uaccess.c
1 /* User memory access */
2 #include "qemu/osdep.h"
3 #include "qemu/cutils.h"
4
5 #include "qemu.h"
6
7 void *lock_user(int type, abi_ulong guest_addr, size_t len, bool copy)
8 {
9 void *host_addr;
10
11 guest_addr = cpu_untagged_addr(thread_cpu, guest_addr);
12 if (!access_ok_untagged(type, guest_addr, len)) {
13 return NULL;
14 }
15 host_addr = g2h_untagged(guest_addr);
16 #ifdef DEBUG_REMAP
17 if (copy) {
18 host_addr = g_memdup(host_addr, len);
19 } else {
20 host_addr = g_malloc0(len);
21 }
22 #endif
23 return host_addr;
24 }
25
26 #ifdef DEBUG_REMAP
27 void unlock_user(void *host_ptr, abi_ulong guest_addr, size_t len);
28 {
29 void *host_ptr_conv;
30
31 if (!host_ptr) {
32 return;
33 }
34 host_ptr_conv = g2h(thread_cpu, guest_addr);
35 if (host_ptr == host_ptr_conv) {
36 return;
37 }
38 if (len != 0) {
39 memcpy(host_ptr_conv, host_ptr, len);
40 }
41 g_free(host_ptr);
42 }
43 #endif
44
45 void *lock_user_string(abi_ulong guest_addr)
46 {
47 ssize_t len = target_strlen(guest_addr);
48 if (len < 0) {
49 return NULL;
50 }
51 return lock_user(VERIFY_READ, guest_addr, (size_t)len + 1, 1);
52 }
53
54 /* copy_from_user() and copy_to_user() are usually used to copy data
55 * buffers between the target and host. These internally perform
56 * locking/unlocking of the memory.
57 */
58 int copy_from_user(void *hptr, abi_ulong gaddr, size_t len)
59 {
60 int ret = 0;
61 void *ghptr = lock_user(VERIFY_READ, gaddr, len, 1);
62
63 if (ghptr) {
64 memcpy(hptr, ghptr, len);
65 unlock_user(ghptr, gaddr, 0);
66 } else {
67 ret = -TARGET_EFAULT;
68 }
69 return ret;
70 }
71
72 int copy_to_user(abi_ulong gaddr, void *hptr, size_t len)
73 {
74 int ret = 0;
75 void *ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0);
76
77 if (ghptr) {
78 memcpy(ghptr, hptr, len);
79 unlock_user(ghptr, gaddr, len);
80 } else {
81 ret = -TARGET_EFAULT;
82 }
83
84 return ret;
85 }
86
87 /* Return the length of a string in target memory or -TARGET_EFAULT if
88 access error */
89 ssize_t target_strlen(abi_ulong guest_addr1)
90 {
91 uint8_t *ptr;
92 abi_ulong guest_addr;
93 size_t max_len, len;
94
95 guest_addr = guest_addr1;
96 for(;;) {
97 max_len = TARGET_PAGE_SIZE - (guest_addr & ~TARGET_PAGE_MASK);
98 ptr = lock_user(VERIFY_READ, guest_addr, max_len, 1);
99 if (!ptr)
100 return -TARGET_EFAULT;
101 len = qemu_strnlen((const char *)ptr, max_len);
102 unlock_user(ptr, guest_addr, 0);
103 guest_addr += len;
104 /* we don't allow wrapping or integer overflow */
105 if (guest_addr == 0 || (guest_addr - guest_addr1) > 0x7fffffff) {
106 return -TARGET_EFAULT;
107 }
108 if (len != max_len) {
109 break;
110 }
111 }
112 return guest_addr - guest_addr1;
113 }