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package internal
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"syscall"
"unsafe"
"ior/internal/flags"
"ior/internal/statsengine"
"ior/internal/types"
bpf "github.com/aquasecurity/libbpfgo"
)
const (
syscallAggregateMapName = "syscall_aggregate_map"
syscallSamplingRateMapName = "syscall_sampling_rate_map"
)
type rawSyscallAggregate struct {
Count uint64
Errors uint64
TotalDuration uint64
MinDuration uint64
MaxDuration uint64
Histogram [8]uint64
}
type syscallAggregateConsumer struct {
aggregateMap *bpf.BPFMap
}
func newSyscallAggregateConsumer(module *bpf.Module) (*syscallAggregateConsumer, error) {
if module == nil {
return nil, errors.New("nil bpf module")
}
aggregateMap, err := module.GetMap(syscallAggregateMapName)
if err != nil {
return nil, fmt.Errorf("get %s: %w", syscallAggregateMapName, err)
}
return &syscallAggregateConsumer{aggregateMap: aggregateMap}, nil
}
func (c *syscallAggregateConsumer) Drain() ([]statsengine.SyscallAggregate, error) {
if c == nil || c.aggregateMap == nil {
return nil, nil
}
iter := c.aggregateMap.Iterator()
rows := make([]statsengine.SyscallAggregate, 0, 64)
for iter.Next() {
keyRaw := append([]byte(nil), iter.Key()...)
if len(keyRaw) != 4 {
continue
}
key := binary.LittleEndian.Uint32(keyRaw)
valueRaw, err := c.aggregateMap.GetValueAndDeleteKey(unsafe.Pointer(&key))
if err != nil {
if errors.Is(err, syscall.ENOENT) {
continue
}
return nil, fmt.Errorf("drain aggregate for trace id %d: %w", key, err)
}
raw, err := decodeRawSyscallAggregate(valueRaw)
if err != nil {
return nil, fmt.Errorf("decode aggregate for trace id %d: %w", key, err)
}
rows = append(rows, statsengine.SyscallAggregate{
TraceID: types.TraceId(key),
Count: raw.Count,
Errors: raw.Errors,
TotalLatencyNs: raw.TotalDuration,
MinLatencyNs: raw.MinDuration,
MaxLatencyNs: raw.MaxDuration,
LatencyHistogramNs: raw.Histogram,
})
}
if err := iter.Err(); err != nil {
return nil, fmt.Errorf("iterate %s: %w", syscallAggregateMapName, err)
}
return rows, nil
}
func decodeRawSyscallAggregate(raw []byte) (rawSyscallAggregate, error) {
var out rawSyscallAggregate
expectedSize := binary.Size(out)
if len(raw) != expectedSize {
return rawSyscallAggregate{}, fmt.Errorf("invalid aggregate value size %d (want %d)", len(raw), expectedSize)
}
if err := binary.Read(bytes.NewReader(raw), binary.LittleEndian, &out); err != nil {
return rawSyscallAggregate{}, err
}
return out, nil
}
func applySyscallSamplingRates(cfg flags.Config, module *bpf.Module) error {
samplingMap, err := module.GetMap(syscallSamplingRateMapName)
if err != nil {
return fmt.Errorf("get %s: %w", syscallSamplingRateMapName, err)
}
for traceID, rate := range buildSyscallSamplingRates(cfg) {
key := uint32(traceID)
value := rate
if err := samplingMap.Update(unsafe.Pointer(&key), unsafe.Pointer(&value)); err != nil {
return fmt.Errorf("set sampling rate for %s to %d: %w", traceID.String(), rate, err)
}
}
return nil
}
func buildSyscallSamplingRates(cfg flags.Config) map[types.TraceId]uint32 {
rates := make(map[types.TraceId]uint32)
for _, enterID := range types.EnterTraceIDs() {
if rate, ok := cfg.SyscallFamilySamplingRates[enterID.Family()]; ok {
rates[enterID] = rate
}
}
for syscallName, rate := range cfg.SyscallSamplingRates {
enterID, ok := types.EnterTraceIDByName(syscallName)
if !ok {
continue
}
rates[enterID] = rate
}
return rates
}
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