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
33unsigned long
34__stdcall
35NtAllocateUuids(
36   void* p1,  // 8 bytes
37   void* p2,  // 4 bytes
38   void* p3   // 4 bytes
39   );
40
41typedef
42unsigned long
43(__stdcall*
44NtAllocateUuids_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)
59struct _TEB*
60__stdcall
61NtCurrentTeb(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
70static
71int
72Nt5(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
81void 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