-
Notifications
You must be signed in to change notification settings - Fork 177
/
provider.go
301 lines (256 loc) · 9.08 KB
/
provider.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
//go:build windows
// +build windows
package etw
import (
"crypto/sha1" //nolint:gosec // not used for secure application
"encoding/binary"
"strings"
"unicode/utf16"
"github.com/Microsoft/go-winio/pkg/guid"
"golang.org/x/sys/windows"
)
// Provider represents an ETW event provider. It is identified by a provider
// name and ID (GUID), which should always have a 1:1 mapping to each other
// (e.g. don't use multiple provider names with the same ID, or vice versa).
type Provider struct {
ID guid.GUID
handle providerHandle
metadata []byte
callback EnableCallback
index uint
enabled bool
level Level
keywordAny uint64
keywordAll uint64
}
// String returns the `provider`.ID as a string.
func (provider *Provider) String() string {
if provider == nil {
return "<nil>"
}
return provider.ID.String()
}
type providerHandle uint64
// ProviderState informs the provider EnableCallback what action is being
// performed.
type ProviderState uint32
const (
// ProviderStateDisable indicates the provider is being disabled.
ProviderStateDisable ProviderState = iota
// ProviderStateEnable indicates the provider is being enabled.
ProviderStateEnable
// ProviderStateCaptureState indicates the provider is having its current
// state snap-shotted.
ProviderStateCaptureState
)
type eventInfoClass uint32
//nolint:deadcode,varcheck // keep unused constants for potential future use
const (
eventInfoClassProviderBinaryTrackInfo eventInfoClass = iota
eventInfoClassProviderSetReserved1
eventInfoClassProviderSetTraits
eventInfoClassProviderUseDescriptorType
)
// EnableCallback is the form of the callback function that receives provider
// enable/disable notifications from ETW.
type EnableCallback func(guid.GUID, ProviderState, Level, uint64, uint64, uintptr)
func providerCallback(
sourceID guid.GUID,
state ProviderState,
level Level,
matchAnyKeyword uint64,
matchAllKeyword uint64,
filterData uintptr,
i uintptr,
) {
provider := providers.getProvider(uint(i))
switch state {
case ProviderStateCaptureState:
case ProviderStateDisable:
provider.enabled = false
case ProviderStateEnable:
provider.enabled = true
provider.level = level
provider.keywordAny = matchAnyKeyword
provider.keywordAll = matchAllKeyword
}
if provider.callback != nil {
provider.callback(sourceID, state, level, matchAnyKeyword, matchAllKeyword, filterData)
}
}
// providerIDFromName generates a provider ID based on the provider name. It
// uses the same algorithm as used by .NET's EventSource class, which is based
// on RFC 4122. More information on the algorithm can be found here:
// https://blogs.msdn.microsoft.com/dcook/2015/09/08/etw-provider-names-and-guids/
//
// The algorithm is roughly the RFC 4122 algorithm for a V5 UUID, but differs in
// the following ways:
// - The input name is first upper-cased, UTF16-encoded, and converted to
// big-endian.
// - No variant is set on the result UUID.
// - The result UUID is treated as being in little-endian format, rather than
// big-endian.
func providerIDFromName(name string) guid.GUID {
buffer := sha1.New() //nolint:gosec // not used for secure application
namespace := guid.GUID{
Data1: 0x482C2DB2,
Data2: 0xC390,
Data3: 0x47C8,
Data4: [8]byte{0x87, 0xF8, 0x1A, 0x15, 0xBF, 0xC1, 0x30, 0xFB},
}
namespaceBytes := namespace.ToArray()
buffer.Write(namespaceBytes[:])
_ = binary.Write(buffer, binary.BigEndian, utf16.Encode([]rune(strings.ToUpper(name))))
sum := buffer.Sum(nil)
sum[7] = (sum[7] & 0xf) | 0x50
a := [16]byte{}
copy(a[:], sum)
return guid.FromWindowsArray(a)
}
type providerOpts struct {
callback EnableCallback
id guid.GUID
group guid.GUID
}
// ProviderOpt allows the caller to specify provider options to
// NewProviderWithOptions.
type ProviderOpt func(*providerOpts)
// WithCallback is used to provide a callback option to NewProviderWithOptions.
func WithCallback(callback EnableCallback) ProviderOpt {
return func(opts *providerOpts) {
opts.callback = callback
}
}
// WithID is used to provide a provider ID option to NewProviderWithOptions.
func WithID(id guid.GUID) ProviderOpt {
return func(opts *providerOpts) {
opts.id = id
}
}
// WithGroup is used to provide a provider group option to NewProviderWithOptions.
func WithGroup(group guid.GUID) ProviderOpt {
return func(opts *providerOpts) {
opts.group = group
}
}
// NewProviderWithID creates and registers a new ETW provider, allowing the
// provider ID to be manually specified. This is most useful when there is an
// existing provider ID that must be used to conform to existing diagnostic
// infrastructure.
func NewProviderWithID(name string, id guid.GUID, callback EnableCallback) (provider *Provider, err error) {
return NewProviderWithOptions(name, WithID(id), WithCallback(callback))
}
// NewProvider creates and registers a new ETW provider. The provider ID is
// generated based on the provider name.
func NewProvider(name string, callback EnableCallback) (provider *Provider, err error) {
return NewProviderWithOptions(name, WithCallback(callback))
}
// Close unregisters the provider.
func (provider *Provider) Close() error {
if provider == nil {
return nil
}
providers.removeProvider(provider)
return eventUnregister(provider.handle)
}
// IsEnabled calls IsEnabledForLevelAndKeywords with LevelAlways and all
// keywords set.
func (provider *Provider) IsEnabled() bool {
return provider.IsEnabledForLevelAndKeywords(LevelAlways, ^uint64(0))
}
// IsEnabledForLevel calls IsEnabledForLevelAndKeywords with the specified level
// and all keywords set.
func (provider *Provider) IsEnabledForLevel(level Level) bool {
return provider.IsEnabledForLevelAndKeywords(level, ^uint64(0))
}
// IsEnabledForLevelAndKeywords allows event producer code to check if there are
// any event sessions that are interested in an event, based on the event level
// and keywords. Although this check happens automatically in the ETW
// infrastructure, it can be useful to check if an event will actually be
// consumed before doing expensive work to build the event data.
func (provider *Provider) IsEnabledForLevelAndKeywords(level Level, keywords uint64) bool {
if provider == nil {
return false
}
if !provider.enabled {
return false
}
// ETW automatically sets the level to 255 if it is specified as 0, so we
// don't need to worry about the level=0 (all events) case.
if level > provider.level {
return false
}
if keywords != 0 && (keywords&provider.keywordAny == 0 || keywords&provider.keywordAll != provider.keywordAll) {
return false
}
return true
}
// WriteEvent writes a single ETW event from the provider. The event is
// constructed based on the EventOpt and FieldOpt values that are passed as
// opts.
func (provider *Provider) WriteEvent(name string, eventOpts []EventOpt, fieldOpts []FieldOpt) error {
if provider == nil {
return nil
}
options := eventOptions{descriptor: newEventDescriptor()}
em := &eventMetadata{}
ed := &eventData{}
// We need to evaluate the EventOpts first since they might change tags, and
// we write out the tags before evaluating FieldOpts.
for _, opt := range eventOpts {
opt(&options)
}
if !provider.IsEnabledForLevelAndKeywords(options.descriptor.level, options.descriptor.keyword) {
return nil
}
em.writeEventHeader(name, options.tags)
for _, opt := range fieldOpts {
opt(em, ed)
}
// Don't pass a data blob if there is no event data. There will always be
// event metadata (e.g. for the name) so we don't need to do this check for
// the metadata.
dataBlobs := [][]byte{}
if len(ed.toBytes()) > 0 {
dataBlobs = [][]byte{ed.toBytes()}
}
return provider.writeEventRaw(
options.descriptor,
options.activityID,
options.relatedActivityID,
[][]byte{em.toBytes()},
dataBlobs,
)
}
// writeEventRaw writes a single ETW event from the provider. This function is
// less abstracted than WriteEvent, and presents a fairly direct interface to
// the event writing functionality. It expects a series of event metadata and
// event data blobs to be passed in, which must conform to the TraceLogging
// schema. The functions on EventMetadata and EventData can help with creating
// these blobs. The blobs of each type are effectively concatenated together by
// the ETW infrastructure.
func (provider *Provider) writeEventRaw(
descriptor *eventDescriptor,
activityID guid.GUID,
relatedActivityID guid.GUID,
metadataBlobs [][]byte,
dataBlobs [][]byte) error {
dataDescriptorCount := uint32(1 + len(metadataBlobs) + len(dataBlobs))
dataDescriptors := make([]eventDataDescriptor, 0, dataDescriptorCount)
dataDescriptors = append(dataDescriptors,
newEventDataDescriptor(eventDataDescriptorTypeProviderMetadata, provider.metadata))
for _, blob := range metadataBlobs {
dataDescriptors = append(dataDescriptors,
newEventDataDescriptor(eventDataDescriptorTypeEventMetadata, blob))
}
for _, blob := range dataBlobs {
dataDescriptors = append(dataDescriptors,
newEventDataDescriptor(eventDataDescriptorTypeUserData, blob))
}
return eventWriteTransfer(provider.handle,
descriptor,
(*windows.GUID)(&activityID),
(*windows.GUID)(&relatedActivityID),
dataDescriptorCount,
&dataDescriptors[0])
}