ReactOS 0.4.15-dev-5672-gf73ac17
fxtelemetry.cpp
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1/*++
2
3Copyright (c) Microsoft Corporation
4
5Module Name:
6
7 FxTelemetry.cpp
8
9Abstract:
10
11 This module implements a telemetry methods.
12
13Author:
14
15
16
17Environment:
18
19 Both kernel and user mode
20
21Revision History:
22
23Notes:
24
25--*/
26
27
28
29#include "fxsupportpch.hpp"
30
31#if (FX_CORE_MODE == FX_CORE_KERNEL_MODE)
32#include "fxldr.h"
33#include <ntstrsafe.h>
34#else
35#include "driverframeworks-usermode-umevents.h"
36#include "fxldrum.h"
37#endif
38
39extern "C" {
40#if defined(EVENT_TRACING)
41#include "fxtelemetry.tmh"
42#endif
43}
44
45#if defined(__cplusplus)
46extern "C" {
47#endif
48
49
50
51
52
53VOID
57 )
58/*++
59
60Routine Description:
61
62 Given a potential full path name, return just the filename portion, OR,
63 Given a potential full registry path name, return just the subkey portion.
64
65 Pointer to the filename protion in the full path name string, OR,
66 Pointer to the subkey portion in the full registry path name.
67
68Arguments:
69
70 Path - Pointer to the full path name string.
71
72 Name - Pointer to receive the name
73
74Return Value:
75 None
76
77--*/
78{
79 BOOLEAN foundSlash;
80
81 ASSERT(Path != NULL);
82
83 //
84 // Ideally a check of Path->Length == 0 would be sufficient except that
85 // PreFAST thinks that Length can be odd, so it thinks Length == 1 is possible.
86 // Comparing Length < sizeof(WCHAR) satisfies PreFAST and keeps the logic
87 // at runtime correct.
88 //
89 if (Path->Length < sizeof(WCHAR)) {
91 return;
92 }
93
94 //
95 // Initialize Name to point to the last WCHAR of the buffer and we will work
96 // our way backwards to the beginning of the string or a \
97 //
98
99 Name->Buffer = WDF_PTR_ADD_OFFSET_TYPE(Path->Buffer,
100 Path->Length - sizeof(WCHAR),
101 PWCH);
102 Name->Length = sizeof(WCHAR);
103 foundSlash = FALSE;
104
105 while (Name->Buffer >= Path->Buffer) {
106 if (*Name->Buffer == L'\\') {
107 //
108 // Skip the \ in the buffer moving forward a character and adjusting
109 // the length
110 //
111 foundSlash = TRUE;
112 Name->Buffer++;
113 Name->Length -= sizeof(WCHAR);
114 break;
115 }
116
117 //
118 // Move backwards in the string
119 //
120 Name->Buffer--;
121 Name->Length += sizeof(WCHAR);
122 }
123
124 if (foundSlash && Name->Length == 0) {
125 //
126 // Handle the case where a slash was found and it is the only character
127 //
128 Name->Buffer = NULL;
129 }
130 else if (foundSlash == FALSE) {
131 //
132 // Handle the case where no slash was found. In this case, Name->Buffer
133 // points to one WCHAR before the beginning of the string.
134 //
135 Name->Length -= sizeof(WCHAR);
136 Name->Buffer++;
137 }
138
139 //
140 // Need to set MaximumLength to the same value as Length so that the struct
141 // format is valid.
142 //
143 Name->MaximumLength = Name->Length;
144}
145
146#if defined(__cplusplus)
147}
148#endif
149
unsigned char BOOLEAN
PRTL_UNICODE_STRING_BUFFER Path
#define NULL
Definition: types.h:112
#define TRUE
Definition: types.h:120
#define FALSE
Definition: types.h:117
VOID GetNameFromPath(_In_ PCUNICODE_STRING Path, _Out_ PUNICODE_STRING Name)
Definition: fxtelemetry.cpp:54
#define ASSERT(a)
Definition: mode.c:44
#define _Out_
Definition: ms_sal.h:345
#define _In_
Definition: ms_sal.h:308
WCHAR * PWCH
Definition: ntbasedef.h:410
#define L(x)
Definition: ntvdm.h:50
#define RtlZeroMemory(Destination, Length)
Definition: typedefs.h:262
#define WDF_PTR_ADD_OFFSET_TYPE(_ptr, _offset, _type)
Definition: wdfcore.h:141
__wchar_t WCHAR
Definition: xmlstorage.h:180