-
Notifications
You must be signed in to change notification settings - Fork 2.1k
/
helpers.go
266 lines (221 loc) · 7.01 KB
/
helpers.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
//go:build linux && amd64 && go1.16
package ebpf
import (
"debug/elf"
"encoding/binary"
"errors"
"reflect"
"runtime"
"sync"
"unsafe"
"github.com/go-delve/delve/pkg/dwarf/godwarf"
"github.com/go-delve/delve/pkg/dwarf/op"
"github.com/cilium/ebpf"
"github.com/cilium/ebpf/link"
"github.com/cilium/ebpf/ringbuf"
"github.com/cilium/ebpf/rlimit"
)
//lint:file-ignore U1000 some fields are used by the C program
// function_parameter_t tracks function_parameter_t from function_vals.bpf.h
type function_parameter_t struct {
kind uint32
size uint32
offset int32
in_reg bool
n_pieces int32
reg_nums [6]int32
daddr uint64
val [0x30]byte
deref_val [0x30]byte
}
// function_parameter_list_t tracks function_parameter_list_t from function_vals.bpf.h
type function_parameter_list_t struct {
goid_offset uint32
g_addr_offset uint64
goroutine_id uint32
fn_addr uint64
is_ret bool
n_parameters uint32
params [6]function_parameter_t
n_ret_parameters uint32
ret_params [6]function_parameter_t
}
//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -tags "go1.16" -target amd64 trace bpf/trace.bpf.c -- -I./bpf/include
const FakeAddressBase = 0xbeed000000000000
type EBPFContext struct {
objs *traceObjects
bpfEvents chan []byte
bpfRingBuf *ringbuf.Reader
executable *link.Executable
bpfArgMap *ebpf.Map
links []link.Link
parsedBpfEvents []RawUProbeParams
m sync.Mutex
}
func (ctx *EBPFContext) Close() {
if ctx.objs != nil {
ctx.objs.Close()
}
for _, l := range ctx.links {
l.Close()
}
}
func (ctx *EBPFContext) AttachUprobe(pid int, name string, offset uint64) error {
if ctx.executable == nil {
return errors.New("no eBPF program loaded")
}
l, err := ctx.executable.Uprobe(name, ctx.objs.tracePrograms.UprobeDlvTrace, &link.UprobeOptions{PID: pid, Offset: offset})
ctx.links = append(ctx.links, l)
return err
}
func (ctx *EBPFContext) UpdateArgMap(key uint64, goidOffset int64, args []UProbeArgMap, gAddrOffset uint64, isret bool) error {
if ctx.bpfArgMap == nil {
return errors.New("eBPF map not loaded")
}
params := createFunctionParameterList(key, goidOffset, args, isret)
params.g_addr_offset = gAddrOffset
return ctx.bpfArgMap.Update(unsafe.Pointer(&key), unsafe.Pointer(¶ms), ebpf.UpdateAny)
}
func (ctx *EBPFContext) GetBufferedTracepoints() []RawUProbeParams {
ctx.m.Lock()
defer ctx.m.Unlock()
if len(ctx.parsedBpfEvents) == 0 {
return make([]RawUProbeParams, 0)
}
events := make([]RawUProbeParams, len(ctx.parsedBpfEvents))
copy(events, ctx.parsedBpfEvents)
ctx.parsedBpfEvents = ctx.parsedBpfEvents[:0]
return events
}
func LoadEBPFTracingProgram(path string) (*EBPFContext, error) {
var (
ctx EBPFContext
err error
objs traceObjects
)
if err = rlimit.RemoveMemlock(); err != nil {
return nil, err
}
ctx.executable, err = link.OpenExecutable(path)
if err != nil {
return nil, err
}
if err := loadTraceObjects(&objs, nil); err != nil {
return nil, err
}
ctx.objs = &objs
ctx.bpfRingBuf, err = ringbuf.NewReader(objs.Events)
if err != nil {
return nil, err
}
ctx.bpfArgMap = objs.ArgMap
// TODO(derekparker): This should eventually be moved to a more generalized place.
go func() {
for {
e, err := ctx.bpfRingBuf.Read()
if err != nil {
return
}
parsed := parseFunctionParameterList(e.RawSample)
ctx.m.Lock()
ctx.parsedBpfEvents = append(ctx.parsedBpfEvents, parsed)
ctx.m.Unlock()
}
}()
return &ctx, nil
}
func parseFunctionParameterList(rawParamBytes []byte) RawUProbeParams {
params := (*function_parameter_list_t)(unsafe.Pointer(&rawParamBytes[0]))
defer runtime.KeepAlive(params) // Ensure the param is not garbage collected.
var rawParams RawUProbeParams
rawParams.FnAddr = int(params.fn_addr)
rawParams.GoroutineID = int(params.goroutine_id)
rawParams.IsRet = params.is_ret
parseParam := func(param function_parameter_t) *RawUProbeParam {
iparam := &RawUProbeParam{}
data := make([]byte, 0x60)
ret := param
iparam.Kind = reflect.Kind(ret.kind)
val := ret.val[:ret.size]
rawDerefValue := ret.deref_val[:0x30]
copy(data, val)
copy(data[0x30:], rawDerefValue)
iparam.Data = data
pieces := make([]op.Piece, 0, 2)
pieces = append(pieces, op.Piece{Size: 0x30, Kind: op.AddrPiece, Val: FakeAddressBase})
pieces = append(pieces, op.Piece{Size: 0x30, Kind: op.AddrPiece, Val: FakeAddressBase + 0x30})
iparam.Pieces = pieces
iparam.Addr = FakeAddressBase
switch iparam.Kind {
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
iparam.RealType = &godwarf.UintType{BasicType: godwarf.BasicType{CommonType: godwarf.CommonType{ByteSize: 8}}}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Bool:
iparam.RealType = &godwarf.IntType{BasicType: godwarf.BasicType{CommonType: godwarf.CommonType{ByteSize: 8}}}
case reflect.String:
strLen := binary.LittleEndian.Uint64(val[8:])
iparam.Base = FakeAddressBase + 0x30
iparam.Len = int64(strLen)
}
return iparam
}
for i := 0; i < int(params.n_parameters); i++ {
rawParams.InputParams = append(rawParams.InputParams, parseParam(params.params[i]))
}
for i := 0; i < int(params.n_ret_parameters); i++ {
rawParams.ReturnParams = append(rawParams.ReturnParams, parseParam(params.ret_params[i]))
}
return rawParams
}
func createFunctionParameterList(entry uint64, goidOffset int64, args []UProbeArgMap, isret bool) function_parameter_list_t {
var params function_parameter_list_t
params.goid_offset = uint32(goidOffset)
params.fn_addr = entry
params.is_ret = isret
params.n_parameters = 0
params.n_ret_parameters = 0
for _, arg := range args {
var param function_parameter_t
param.size = uint32(arg.Size)
param.offset = int32(arg.Offset)
param.kind = uint32(arg.Kind)
if arg.InReg {
param.in_reg = true
param.n_pieces = int32(len(arg.Pieces))
for i := range arg.Pieces {
if i > 5 {
break
}
param.reg_nums[i] = int32(arg.Pieces[i])
}
}
if !arg.Ret {
params.params[params.n_parameters] = param
params.n_parameters++
} else {
params.ret_params[params.n_ret_parameters] = param
params.n_ret_parameters++
}
}
return params
}
func AddressToOffset(f *elf.File, addr uint64) (uint64, error) {
sectionsToSearchForSymbol := []*elf.Section{}
for i := range f.Sections {
if f.Sections[i].Flags == elf.SHF_ALLOC+elf.SHF_EXECINSTR {
sectionsToSearchForSymbol = append(sectionsToSearchForSymbol, f.Sections[i])
}
}
var executableSection *elf.Section
// Find what section the symbol is in by checking the executable section's
// addr space.
for m := range sectionsToSearchForSymbol {
if addr > sectionsToSearchForSymbol[m].Addr &&
addr < sectionsToSearchForSymbol[m].Addr+sectionsToSearchForSymbol[m].Size {
executableSection = sectionsToSearchForSymbol[m]
}
}
if executableSection == nil {
return 0, errors.New("could not find symbol in executable sections of binary")
}
return uint64(addr - executableSection.Addr + executableSection.Offset), nil
}