/
kernel_config.go
399 lines (348 loc) · 13.1 KB
/
kernel_config.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
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
package helpers
import (
"bufio"
"compress/gzip"
"fmt"
"io"
"os"
"path/filepath"
"strings"
)
// KernelConfigOption is an abstraction of the key in key=value syntax of the kernel config file
type KernelConfigOption uint32
// KernelConfigOptionValue is an abstraction of the value in key=value syntax of kernel config file
type KernelConfigOptionValue uint8
const (
UNDEFINED KernelConfigOptionValue = iota
BUILTIN
MODULE
STRING
ANY
)
func (k KernelConfigOption) String() string {
return kernelConfigKeyIDToString[k]
}
func (k KernelConfigOptionValue) String() string {
switch k {
case UNDEFINED:
return "UNDEFINED"
case BUILTIN:
return "BUILTIN"
case MODULE:
return "MODULE"
case STRING:
return "STRING"
case ANY:
return "ANY"
}
return ""
}
// These constants are a limited number of the total kernel config options,
// but are provided because they are most relevant for BPF development.
const (
CONFIG_BPF KernelConfigOption = iota + 1
CONFIG_BPF_SYSCALL
CONFIG_HAVE_EBPF_JIT
CONFIG_BPF_JIT
CONFIG_BPF_JIT_ALWAYS_ON
CONFIG_CGROUPS
CONFIG_CGROUP_BPF
CONFIG_CGROUP_NET_CLASSID
CONFIG_SOCK_CGROUP_DATA
CONFIG_BPF_EVENTS
CONFIG_KPROBE_EVENTS
CONFIG_UPROBE_EVENTS
CONFIG_TRACING
CONFIG_FTRACE_SYSCALLS
CONFIG_FUNCTION_ERROR_INJECTION
CONFIG_BPF_KPROBE_OVERRIDE
CONFIG_NET
CONFIG_XDP_SOCKETS
CONFIG_LWTUNNEL_BPF
CONFIG_NET_ACT_BPF
CONFIG_NET_CLS_BPF
CONFIG_NET_CLS_ACT
CONFIG_NET_SCH_INGRESS
CONFIG_XFRM
CONFIG_IP_ROUTE_CLASSID
CONFIG_IPV6_SEG6_BPF
CONFIG_BPF_LIRC_MODE2
CONFIG_BPF_STREAM_PARSER
CONFIG_NETFILTER_XT_MATCH_BPF
CONFIG_BPFILTER
CONFIG_BPFILTER_UMH
CONFIG_TEST_BPF
CONFIG_HZ
CONFIG_DEBUG_INFO_BTF
CONFIG_DEBUG_INFO_BTF_MODULES
CONFIG_BPF_LSM
CONFIG_BPF_PRELOAD
CONFIG_BPF_PRELOAD_UMD
CUSTOM_OPTION_START KernelConfigOption = 1000
)
var kernelConfigKeyStringToID = map[string]KernelConfigOption{
"CONFIG_BPF": CONFIG_BPF,
"CONFIG_BPF_SYSCALL": CONFIG_BPF_SYSCALL,
"CONFIG_HAVE_EBPF_JIT": CONFIG_HAVE_EBPF_JIT,
"CONFIG_BPF_JIT": CONFIG_BPF_JIT,
"CONFIG_BPF_JIT_ALWAYS_ON": CONFIG_BPF_JIT_ALWAYS_ON,
"CONFIG_CGROUPS": CONFIG_CGROUPS,
"CONFIG_CGROUP_BPF": CONFIG_CGROUP_BPF,
"CONFIG_CGROUP_NET_CLASSID": CONFIG_CGROUP_NET_CLASSID,
"CONFIG_SOCK_CGROUP_DATA": CONFIG_SOCK_CGROUP_DATA,
"CONFIG_BPF_EVENTS": CONFIG_BPF_EVENTS,
"CONFIG_KPROBE_EVENTS": CONFIG_KPROBE_EVENTS,
"CONFIG_UPROBE_EVENTS": CONFIG_UPROBE_EVENTS,
"CONFIG_TRACING": CONFIG_TRACING,
"CONFIG_FTRACE_SYSCALLS": CONFIG_FTRACE_SYSCALLS,
"CONFIG_FUNCTION_ERROR_INJECTION": CONFIG_FUNCTION_ERROR_INJECTION,
"CONFIG_BPF_KPROBE_OVERRIDE": CONFIG_BPF_KPROBE_OVERRIDE,
"CONFIG_NET": CONFIG_NET,
"CONFIG_XDP_SOCKETS": CONFIG_XDP_SOCKETS,
"CONFIG_LWTUNNEL_BPF": CONFIG_LWTUNNEL_BPF,
"CONFIG_NET_ACT_BPF": CONFIG_NET_ACT_BPF,
"CONFIG_NET_CLS_BPF": CONFIG_NET_CLS_BPF,
"CONFIG_NET_CLS_ACT": CONFIG_NET_CLS_ACT,
"CONFIG_NET_SCH_INGRESS": CONFIG_NET_SCH_INGRESS,
"CONFIG_XFRM": CONFIG_XFRM,
"CONFIG_IP_ROUTE_CLASSID": CONFIG_IP_ROUTE_CLASSID,
"CONFIG_IPV6_SEG6_BPF": CONFIG_IPV6_SEG6_BPF,
"CONFIG_BPF_LIRC_MODE2": CONFIG_BPF_LIRC_MODE2,
"CONFIG_BPF_STREAM_PARSER": CONFIG_BPF_STREAM_PARSER,
"CONFIG_NETFILTER_XT_MATCH_BPF": CONFIG_NETFILTER_XT_MATCH_BPF,
"CONFIG_BPFILTER": CONFIG_BPFILTER,
"CONFIG_BPFILTER_UMH": CONFIG_BPFILTER_UMH,
"CONFIG_TEST_BPF": CONFIG_TEST_BPF,
"CONFIG_HZ": CONFIG_HZ,
"CONFIG_DEBUG_INFO_BTF": CONFIG_DEBUG_INFO_BTF,
"CONFIG_DEBUG_INFO_BTF_MODULES": CONFIG_DEBUG_INFO_BTF_MODULES,
"CONFIG_BPF_LSM": CONFIG_BPF_LSM,
"CONFIG_BPF_PRELOAD": CONFIG_BPF_PRELOAD,
"CONFIG_BPF_PRELOAD_UMD": CONFIG_BPF_PRELOAD_UMD,
}
var kernelConfigKeyIDToString = map[KernelConfigOption]string{
CONFIG_BPF: "CONFIG_BPF",
CONFIG_BPF_SYSCALL: "CONFIG_BPF_SYSCALL",
CONFIG_HAVE_EBPF_JIT: "CONFIG_HAVE_EBPF_JIT",
CONFIG_BPF_JIT: "CONFIG_BPF_JIT",
CONFIG_BPF_JIT_ALWAYS_ON: "CONFIG_BPF_JIT_ALWAYS_ON",
CONFIG_CGROUPS: "CONFIG_CGROUPS",
CONFIG_CGROUP_BPF: "CONFIG_CGROUP_BPF",
CONFIG_CGROUP_NET_CLASSID: "CONFIG_CGROUP_NET_CLASSID",
CONFIG_SOCK_CGROUP_DATA: "CONFIG_SOCK_CGROUP_DATA",
CONFIG_BPF_EVENTS: "CONFIG_BPF_EVENTS",
CONFIG_KPROBE_EVENTS: "CONFIG_KPROBE_EVENTS",
CONFIG_UPROBE_EVENTS: "CONFIG_UPROBE_EVENTS",
CONFIG_TRACING: "CONFIG_TRACING",
CONFIG_FTRACE_SYSCALLS: "CONFIG_FTRACE_SYSCALLS",
CONFIG_FUNCTION_ERROR_INJECTION: "CONFIG_FUNCTION_ERROR_INJECTION",
CONFIG_BPF_KPROBE_OVERRIDE: "CONFIG_BPF_KPROBE_OVERRIDE",
CONFIG_NET: "CONFIG_NET",
CONFIG_XDP_SOCKETS: "CONFIG_XDP_SOCKETS",
CONFIG_LWTUNNEL_BPF: "CONFIG_LWTUNNEL_BPF",
CONFIG_NET_ACT_BPF: "CONFIG_NET_ACT_BPF",
CONFIG_NET_CLS_BPF: "CONFIG_NET_CLS_BPF",
CONFIG_NET_CLS_ACT: "CONFIG_NET_CLS_ACT",
CONFIG_NET_SCH_INGRESS: "CONFIG_NET_SCH_INGRESS",
CONFIG_XFRM: "CONFIG_XFRM",
CONFIG_IP_ROUTE_CLASSID: "CONFIG_IP_ROUTE_CLASSID",
CONFIG_IPV6_SEG6_BPF: "CONFIG_IPV6_SEG6_BPF",
CONFIG_BPF_LIRC_MODE2: "CONFIG_BPF_LIRC_MODE2",
CONFIG_BPF_STREAM_PARSER: "CONFIG_BPF_STREAM_PARSER",
CONFIG_NETFILTER_XT_MATCH_BPF: "CONFIG_NETFILTER_XT_MATCH_BPF",
CONFIG_BPFILTER: "CONFIG_BPFILTER",
CONFIG_BPFILTER_UMH: "CONFIG_BPFILTER_UMH",
CONFIG_TEST_BPF: "CONFIG_TEST_BPF",
CONFIG_HZ: "CONFIG_HZ",
CONFIG_DEBUG_INFO_BTF: "CONFIG_DEBUG_INFO_BTF",
CONFIG_DEBUG_INFO_BTF_MODULES: "CONFIG_DEBUG_INFO_BTF_MODULES",
CONFIG_BPF_LSM: "CONFIG_BPF_LSM",
CONFIG_BPF_PRELOAD: "CONFIG_BPF_PRELOAD",
CONFIG_BPF_PRELOAD_UMD: "CONFIG_BPF_PRELOAD_UMD",
}
// KernelConfig is a set of kernel configuration options (currently for running OS only)
type KernelConfig struct {
configs map[KernelConfigOption]interface{} // predominantly KernelConfigOptionValue, sometimes string
needed map[KernelConfigOption]interface{}
kConfigFilePath string
}
// InitKernelConfig inits external KernelConfig object
func InitKernelConfig() (*KernelConfig, error) {
config := KernelConfig{}
// special case: user provided kconfig file (it MUST exist)
osKConfigFilePath, err := checkEnvPath("LIBBPFGO_KCONFIG_FILE") // override /proc/config.gz or /boot/config-$(uname -r) if needed (containers)
if err != nil {
return &config, err
}
if len(osKConfigFilePath) > 2 {
if _, err := os.Stat(osKConfigFilePath); err != nil {
return &config, err
}
config.kConfigFilePath = osKConfigFilePath
if err := config.initKernelConfig(osKConfigFilePath); err != nil {
return &config, err
}
return &config, nil
}
// fastpath: check config.gz in procfs first
configGZ := "/proc/config.gz"
if _, err1 := os.Stat(configGZ); err1 == nil {
config.kConfigFilePath = configGZ
if err2 := config.initKernelConfig(configGZ); err2 != nil {
return &config, err2
}
return &config, nil
} // ignore if /proc/config.gz does not exist
// slowerpath: /boot/$(uname -r)
releaseVersion, err := UnameRelease()
if err != nil {
return &config, err
}
releaseFilePath := fmt.Sprintf("/boot/config-%s", releaseVersion)
config.kConfigFilePath = releaseFilePath
err = config.initKernelConfig(releaseFilePath)
return &config, err
}
// GetKernelConfigFilePath gives the kconfig file chosen by InitKernelConfig during initialization
func (k *KernelConfig) GetKernelConfigFilePath() string {
return k.kConfigFilePath
}
// AddCustomKernelConfig allows user to extend list of possible existing kconfigs to be parsed from kConfigFilePath
func (k *KernelConfig) AddCustomKernelConfig(key KernelConfigOption, value string) error {
if key < CUSTOM_OPTION_START {
return fmt.Errorf("KConfig key index must be bigger than %d (CUSTOM_OPTION_START)\n", CUSTOM_OPTION_START)
}
// extend initial list of kconfig options: add other possible existing ones
kernelConfigKeyIDToString[key] = value
kernelConfigKeyStringToID[value] = key
return nil
}
// LoadKernelConfig will (re)read kconfig file (likely after AddCustomKernelConfig was called)
func (k *KernelConfig) LoadKernelConfig() error {
return k.initKernelConfig(k.kConfigFilePath)
}
// initKernelConfig inits internal KernelConfig data by calling appropriate readConfigFromXXX function
func (k *KernelConfig) initKernelConfig(configFilePath string) error {
if _, err := os.Stat(configFilePath); err != nil {
return fmt.Errorf("could not read %v: %w", configFilePath, err)
}
if strings.Compare(filepath.Ext(configFilePath), ".gz") == 0 {
return k.readConfigFromProcConfigGZ(configFilePath)
}
return k.readConfigFromBootConfigRelease(configFilePath) // assume it is a txt file by default
}
// readConfigFromBootConfigRelease prepares io.Reader (/boot/config-$(uname -r)) for readConfigFromScanner
func (k *KernelConfig) readConfigFromBootConfigRelease(filePath string) error {
file, _ := os.Open(filePath) // already checked
k.readConfigFromScanner(file)
file.Close()
return nil
}
// readConfigFromProcConfigGZ prepares gziped io.Reader (/proc/config.gz) for readConfigFromScanner
func (k *KernelConfig) readConfigFromProcConfigGZ(filePath string) error {
file, _ := os.Open(filePath) // already checked
zreader, _ := gzip.NewReader(file)
k.readConfigFromScanner(zreader)
zreader.Close()
file.Close()
return nil
}
// readConfigFromScanner reads all existing KernelConfigOption's and KernelConfigOptionValue's from given io.Reader
func (k *KernelConfig) readConfigFromScanner(reader io.Reader) {
if k.configs == nil {
k.configs = make(map[KernelConfigOption]interface{})
}
if k.needed == nil {
k.needed = make(map[KernelConfigOption]interface{})
}
scanner := bufio.NewScanner(reader)
for scanner.Scan() {
kv := strings.Split(scanner.Text(), "=")
if len(kv) != 2 {
continue
}
configKeyID := kernelConfigKeyStringToID[kv[0]]
if configKeyID == 0 {
continue
}
if strings.Compare(kv[1], "m") == 0 {
k.configs[configKeyID] = MODULE
} else if strings.Compare(kv[1], "y") == 0 {
k.configs[configKeyID] = BUILTIN
} else {
k.configs[configKeyID] = kv[1]
}
}
}
// GetValue will return a KernelConfigOptionValue for a given KernelConfigOption when this is a BUILTIN or a MODULE
func (k *KernelConfig) GetValue(option KernelConfigOption) KernelConfigOptionValue {
value, ok := k.configs[KernelConfigOption(option)].(KernelConfigOptionValue)
if ok {
return value
}
return UNDEFINED // not an error as the config option might not exist in kconfig file
}
// GetValueString will return a KernelConfigOptionValue for a given KernelConfigOption when this is actually a string
func (k *KernelConfig) GetValueString(option KernelConfigOption) (string, error) {
value, ok := k.configs[option].(string)
if ok {
return value, nil
}
return "", fmt.Errorf("given option's value (%s) is not a string", option)
}
// Exists will return true if a given KernelConfigOption was found in provided KernelConfig
// and it will return false if the KernelConfigOption is not set (# XXXXX is not set)
//
// Examples:
// kernelConfig.Exists(helpers.CONFIG_BPF)
// kernelConfig.Exists(helpers.CONFIG_BPF_PRELOAD)
// kernelConfig.Exists(helpers.CONFIG_HZ)
//
func (k *KernelConfig) Exists(option KernelConfigOption) bool {
if _, ok := k.configs[option]; ok {
return true
}
return false
}
// ExistsValue will return true if a given KernelConfigOption was found in provided KernelConfig
// AND its value is the same as the one provided by KernelConfigOptionValue
func (k *KernelConfig) ExistsValue(option KernelConfigOption, value interface{}) bool {
if cfg, ok := k.configs[option]; ok {
switch cfg.(type) {
case KernelConfigOptionValue:
if value == ANY {
return true
} else if k.configs[option].(KernelConfigOptionValue) == value {
return true
}
case string:
if strings.Compare(k.configs[option].(string), value.(string)) == 0 {
return true
}
}
}
return false
}
// CheckMissing returns an array of KernelConfigOption's that were added to KernelConfig as needed but couldn't be
// found. It returns an empty array if nothing is missing.
func (k *KernelConfig) CheckMissing() []KernelConfigOption {
missing := make([]KernelConfigOption, 0)
for key, value := range k.needed {
if !k.ExistsValue(key, value) {
missing = append(missing, key)
}
}
return missing
}
// AddNeeded adds a KernelConfigOption and its value, if needed, as required for further checks with CheckMissing
//
// Examples:
// kernelConfig.AddNeeded(helpers.CONFIG_BPF, helpers.ANY)
// kernelConfig.AddNeeded(helpers.CONFIG_BPF_PRELOAD, helpers.ANY)
// kernelConfig.AddNeeded(helpers.CONFIG_HZ, "250")
//
func (k *KernelConfig) AddNeeded(option KernelConfigOption, value interface{}) {
if _, ok := kernelConfigKeyIDToString[option]; ok {
k.needed[option] = value
}
}