1 /*
2 * gen_uuid_nt.c -- Use NT api to generate uuid
3 *
4 * Written by Andrey Shedel (andreys@ns.cr.cyco.com)
5 */
6
7
8 #include "uuidP.h"
9
10 #pragma warning(push,4)
11
12 #pragma comment(lib, "ntdll.lib")
13
14 //
15 // Here is a nice example why it's not a good idea
16 // to use native API in ordinary applications.
17 // Number of parameters in function below was changed from 3 to 4
18 // for NT5.
19 //
20 //
21 // NTSYSAPI
22 // NTSTATUS
23 // NTAPI
24 // NtAllocateUuids(
25 // OUT PULONG p1,
26 // OUT PULONG p2,
27 // OUT PULONG p3,
28 // OUT PUCHAR Seed // 6 bytes
29 // );
30 //
31 //
32
33 unsigned long
34 __stdcall
35 NtAllocateUuids(
36 void* p1, // 8 bytes
37 void* p2, // 4 bytes
38 void* p3 // 4 bytes
39 );
40
41 typedef
42 unsigned long
43 (__stdcall*
44 NtAllocateUuids_2000)(
45 void* p1, // 8 bytes
46 void* p2, // 4 bytes
47 void* p3, // 4 bytes
48 void* seed // 6 bytes
49 );
50
51
52
53 //
54 // Nice, but instead of including ntddk.h ot winnt.h
55 // I should define it here because they MISSED __stdcall in those headers.
56 //
57
58 __declspec(dllimport)
59 struct _TEB*
60 __stdcall
61 NtCurrentTeb(void);
62
63
64 //
65 // The only way to get version information from the system is to examine
66 // one stored in PEB. But it's pretty dangerouse because this value could
67 // be altered in image header.
68 //
69
70 static
71 int
Nt5(void)72 Nt5(void)
73 {
74 //return NtCuttentTeb()->Peb->OSMajorVersion >= 5;
75 return (int)*(int*)((char*)(int)(*(int*)((char*)NtCurrentTeb() + 0x30)) + 0xA4) >= 5;
76 }
77
78
79
80
uuid_generate(uuid_t out)81 void uuid_generate(uuid_t out)
82 {
83 if(Nt5())
84 {
85 unsigned char seed[6];
86 ((NtAllocateUuids_2000)NtAllocateUuids)(out, ((char*)out)+8, ((char*)out)+12, &seed[0] );
87 }
88 else
89 {
90 NtAllocateUuids(out, ((char*)out)+8, ((char*)out)+12);
91 }
92 }
93