ebpf/ebpftracer/tracer.go

package ebpftracer

import (
	"bytes"
	debugelf "debug/elf"
	"encoding/binary"
	"encoding/hex"
	"errors"
	"fmt"
	"os"
	"runtime"
	"strconv"
	"strings"
	"time"

	"github.com/cilium/ebpf"
	"github.com/cilium/ebpf/link"
	"github.com/cilium/ebpf/perf"
	"github.com/coroot/coroot-node-agent/common"
	"github.com/coroot/coroot-node-agent/ebpftracer/l7"
	"github.com/coroot/coroot-node-agent/ebpftracer/tracer"
	"github.com/coroot/coroot-node-agent/proc"
	"github.com/coroot/coroot-node-agent/utils"
	"golang.org/x/mod/semver"
	"golang.org/x/sys/unix"
	"inet.af/netaddr"
	"k8s.io/klog/v2"
)

/*
#define TASK_COMM_LEN	16
#define BURST_DATA_BUF_SIZE 8192	// For brust send buffer

#include <linux/types.h>

struct __tuple_t {
	__u8 daddr[16];
	__u8 rcv_saddr[16];
	__u8 addr_len;
	__u8 l4_protocol;
	__u16 dport;
	__u16 num;
};

struct __socket_data {
	__u32 pid;
	__u32 tgid;
	__u64 coroutine_id;
	__u8 source;
	__u8 comm[TASK_COMM_LEN];

	__u64 socket_id;
	struct __tuple_t tuple;
	__u32 extra_data;
	__u32 extra_data_count;

	__u32 tcp_seq;
	__u64 thread_trace_id;

	__u64 timestamp;
	__u8  direction: 1;
	__u8  msg_type:  7;

	__u64 syscall_len;
	__u64 data_seq;
	__u16 data_type;
	__u16 data_len;
	char data[BURST_DATA_BUF_SIZE];
} __attribute__((packed));

struct __socket_data_buffer {
	__u32 events_num;
	__u32 len;
	char data[32760];
};
*/
import "C"

type SocketData C.struct___socket_data
type SocketDataBuffer C.struct___socket_data_buffer

const MaxPayloadSize = 1024

type EventType uint32
type EventReason uint32

const (
	EventTypeProcessStart    EventType = 1
	EventTypeProcessExit     EventType = 2
	EventTypeConnectionOpen  EventType = 3
	EventTypeConnectionClose EventType = 4
	EventTypeConnectionError EventType = 5
	EventTypeListenOpen      EventType = 6
	EventTypeListenClose     EventType = 7
	EventTypeFileOpen        EventType = 8
	EventTypeTCPRetransmit   EventType = 9
	EventTypeL7Request       EventType = 10
	EventTypeFunEnt          EventType = 11
	EventTypeFunRet          EventType = 12

	EventReasonNone    EventReason = 0
	EventReasonOOMKill EventReason = 1
)

type Event struct {
	Type       EventType
	Reason     EventReason
	Pid        uint32
	SrcAddr    netaddr.IPPort
	DstAddr    netaddr.IPPort
	Fd         uint64
	Timestamp  uint64
	L7Request  *l7.RequestData
	StackEvent *StackEvent
}

type perfMapType uint8

const (
	perfMapTypeProcEvents   perfMapType = 1
	perfMapTypeTCPEvents    perfMapType = 2
	perfMapTypeFileEvents   perfMapType = 3
	perfMapTypeL7Events     perfMapType = 4
	perfMapTypeSocketEvents perfMapType = 5
	perfMapTypeEventQueue   perfMapType = 6
)

type Tracer struct {
	kernelVersion    string
	disableL7Tracing bool

	collection *ebpf.Collection
	readers    map[string]*perf.Reader
	links      []link.Link
	uprobes    map[string]*ebpf.Program
	Symbols    []debugelf.Symbol
	Uprobes    []tracer.Uprobe
	UprobesMap map[string]tracer.Uprobe
}

func NewTracer(kernelVersion string, disableL7Tracing bool) *Tracer {
	if disableL7Tracing {
		klog.Infoln("L7 tracing is disabled")
	}
	return &Tracer{
		kernelVersion:    kernelVersion,
		disableL7Tracing: disableL7Tracing,

		readers: map[string]*perf.Reader{},
		uprobes: map[string]*ebpf.Program{},
	}
}

func (t *Tracer) Run(events chan<- Event) error {
	if err := t.ebpf(events); err != nil {
		return err
	}
	if err := t.stack(); err != nil {
		return err
	}
	if err := t.init(events); err != nil {
		return err
	}
	return nil
}

func (t *Tracer) Close() {
	for _, p := range t.uprobes {
		_ = p.Close()
	}
	for _, l := range t.links {
		_ = l.Close()
	}
	for _, r := range t.readers {
		_ = r.Close()
	}
	t.collection.Close()
}

func (t *Tracer) init(ch chan<- Event) error {
	pids, err := proc.ListPids()
	if err != nil {
		return fmt.Errorf("failed to list pids: %w", err)
	}
	for _, pid := range pids {
		ch <- Event{Type: EventTypeProcessStart, Pid: pid}
	}

	fds, sockets := readFds(pids)
	for _, fd := range fds {
		ch <- Event{Type: EventTypeFileOpen, Pid: fd.pid, Fd: fd.fd}
	}

	listens := map[uint64]bool{}
	for _, s := range sockets {
		if s.Listen {
			listens[uint64(s.pid)<<32|uint64(s.SAddr.Port())] = true
		}
	}

	for _, s := range sockets {
		typ := EventTypeConnectionOpen
		if s.Listen {
			typ = EventTypeListenOpen
		} else if listens[uint64(s.pid)<<32|uint64(s.SAddr.Port())] || s.DAddr.Port() > s.SAddr.Port() { // inbound
			continue
		}
		ch <- Event{
			Type:    typ,
			Pid:     s.pid,
			Fd:      s.fd,
			SrcAddr: s.SAddr,
			DstAddr: s.DAddr,
		}
	}
	return nil
}

type perfMap struct {
	name                  string
	perCPUBufferSizePages int
	typ                   perfMapType
}

func (t *Tracer) ebpf(ch chan<- Event) error {
	if _, ok := ebpfProg[runtime.GOARCH]; !ok {
		return fmt.Errorf("unsupported architecture: %s", runtime.GOARCH)
	}
	kv := "v" + common.KernelMajorMinor(t.kernelVersion)
	var prg []byte
	for _, p := range ebpfProg[runtime.GOARCH] {
		if semver.Compare(kv, p.v) >= 0 {
			prg = p.p
			break
		}
	}
	if len(prg) == 0 {
		return fmt.Errorf("unsupported kernel version: %s", t.kernelVersion)
	}
	_, debugFsErr := os.Stat("/sys/kernel/debug/tracing")
	_, traceFsErr := os.Stat("/sys/kernel/tracing")

	if debugFsErr != nil && traceFsErr != nil {
		return fmt.Errorf("kernel tracing is not available: debugfs or tracefs must be mounted")
	}

	collectionSpec, err := ebpf.LoadCollectionSpecFromReader(bytes.NewReader(prg))
	if err != nil {
		return fmt.Errorf("failed to load collection spec: %w", err)
	}
	_ = unix.Setrlimit(unix.RLIMIT_MEMLOCK, &unix.Rlimit{Cur: unix.RLIM_INFINITY, Max: unix.RLIM_INFINITY})
	tracer.PidFilter(collectionSpec)
	opts := &ebpf.CollectionOptions{MapReplacements: make(map[string]*ebpf.Map)}
	for _, spec := range collectionSpec.Maps {
		fmt.Println("maps:", spec.Name)
	}
	tracer.MapInit(collectionSpec, opts)
	// TODO 多进程
	tracer.SetConstants(collectionSpec)
	c, err := ebpf.NewCollectionWithOptions(collectionSpec, *opts)
	if err != nil {
		var verr *ebpf.VerifierError
		if errors.As(err, &verr) {
			klog.Errorf("----%+v", verr)
		}
		return fmt.Errorf("failed to load collection: %w", err)
	}
	tracer.Offset()

	t.collection = c

	perfMaps := []perfMap{
		{name: "proc_events", typ: perfMapTypeProcEvents, perCPUBufferSizePages: 4},
		{name: "tcp_listen_events", typ: perfMapTypeTCPEvents, perCPUBufferSizePages: 4},
		{name: "tcp_connect_events", typ: perfMapTypeTCPEvents, perCPUBufferSizePages: 8},
		{name: "tcp_retransmit_events", typ: perfMapTypeTCPEvents, perCPUBufferSizePages: 4},
		{name: "file_events", typ: perfMapTypeFileEvents, perCPUBufferSizePages: 4},
		{name: "event_queue", typ: perfMapTypeEventQueue, perCPUBufferSizePages: 32},
	}
	fmt.Println(len(collectionSpec.Programs))
	fmt.Println(len(c.Programs))
	tracer.MapInsert(c)
	if !t.disableL7Tracing {
		perfMaps = append(perfMaps, perfMap{name: "l7_events", typ: perfMapTypeL7Events, perCPUBufferSizePages: 32})
	}
	perfMaps = append(perfMaps, perfMap{name: tracer.MAP_PERF_SOCKET_DATA_NAME, typ: perfMapTypeSocketEvents, perCPUBufferSizePages: 64})
	fmt.Println("perfMaps start --")
	for _, pm := range perfMaps {
		fmt.Println("pm.namepm.name: ", pm.name)
		m, ok := t.collection.Maps[pm.name]
		if ok {
			r, err := perf.NewReader(m, pm.perCPUBufferSizePages*os.Getpagesize())
			if err != nil {
				t.Close()
				return fmt.Errorf("failed to create ebpf reader: %w", err)
			}
			t.readers[pm.name] = r
			// event监听
			go runEventsReader(pm.name, r, ch, pm.typ)
		}
	}
	fmt.Println("perfMaps end --")

	for _, programSpec := range collectionSpec.Programs {
		program := t.collection.Programs[programSpec.Name]
		fmt.Println("programSpecprogramSpec:--:", programSpec.Name, programSpec.SectionName, programSpec.Type)
		if t.disableL7Tracing {
			switch programSpec.Name {
			case "sys_enter_writev", "sys_enter_write", "sys_enter_sendto", "sys_enter_sendmsg", "sys_enter_sendmmsg":
				continue
			case "sys_enter_read", "sys_enter_readv", "sys_enter_recvfrom", "sys_enter_recvmsg":
				continue
			case "sys_exit_read", "sys_exit_readv", "sys_exit_recvfrom", "sys_exit_recvmsg":
				continue
			}
		}
		var l link.Link
		switch programSpec.Type {
		case ebpf.TracePoint:
			if strings.Contains(programSpec.SectionName, "prog") {
				continue
			}
			parts := strings.SplitN(programSpec.AttachTo, "/", 2)
			l, err = link.Tracepoint(parts[0], parts[1], program, nil)
		case ebpf.Kprobe:
			if strings.HasPrefix(programSpec.SectionName, "uprobe/") {

				fmt.Println("==============uprobe s")
				fmt.Println(programSpec.Name, programSpec.SectionName, programSpec.Type)
				fmt.Println("==============uprobe e")

				t.uprobes[programSpec.Name] = program
				continue
			}
			l, err = link.Kprobe(programSpec.AttachTo, program, nil)
		}
		if err != nil {
			t.Close()
			return fmt.Errorf("failed to link program: %w", err)
		}
		t.links = append(t.links, l)
	}

	return nil
}

func (t EventType) String() string {
	switch t {
	case EventTypeProcessStart:
		return "process-start"
	case EventTypeProcessExit:
		return "process-exit"
	case EventTypeConnectionOpen:
		return "connection-open"
	case EventTypeConnectionClose:
		return "connection-close"
	case EventTypeConnectionError:
		return "connection-error"
	case EventTypeListenOpen:
		return "listen-open"
	case EventTypeListenClose:
		return "listen-close"
	case EventTypeFileOpen:
		return "file-open"
	case EventTypeTCPRetransmit:
		return "tcp-retransmit"
	case EventTypeL7Request:
		return "l7-request"
	}
	return "unknown: " + strconv.Itoa(int(t))
}

func (t EventReason) String() string {
	switch t {
	case EventReasonNone:
		return "none"
	case EventReasonOOMKill:
		return "oom-kill"
	}
	return "unknown: " + strconv.Itoa(int(t))
}

type procEvent struct {
	Type   EventType
	Pid    uint32
	Reason uint32
}

type tcpEvent struct {
	Fd        uint64
	Timestamp uint64
	Type      EventType
	Pid       uint32
	SPort     uint16
	DPort     uint16
	SAddr     [16]byte
	DAddr     [16]byte
}

type fileEvent struct {
	Type EventType
	Pid  uint32
	Fd   uint64
}

// struct l7_event in l7.c
type l7Event struct {
	Fd                  uint64
	ConnectionTimestamp uint64
	Pid                 uint32
	Status              uint32
	Duration            uint64
	Protocol            uint8
	Method              uint8
	Padding             uint16
	StatementId         uint32
	PayloadSize         uint64
	TraceId             uint64
	TraceStart          uint32
	TraceEnd            uint32
	EventCount          uint32
	AssumedAppId        utils.HashByte
	SpanId              utils.HashByte
	TraceIdFrom         utils.HashByte16
	CalledId            utils.HashByte
	InstanceIdFrom      utils.HashByte
	AppIdFrom           utils.HashByte
	SpanIdFrom          utils.HashByte
}

type SocketDataBufferddd struct {
	EventsNum uint32
	Len       uint32
	Data      [32760]byte
}

const (
	TASK_COMM_LEN       = 16
	BURST_DATA_BUF_SIZE = 8192
)

type Tuple struct {
	Daddr      [16]uint8
	RcvSaddr   [16]uint8
	AddrLen    uint8
	L4Protocol uint8
	Dport      uint16
	Num        uint16
}

type SocketDatadddd struct {
	Pid            uint32 // 表示线程号 如果'pid == tgid'表示一个进程, 否则是线程
	Tgid           uint32 // 进程号
	CoroutineID    uint64
	Source         uint8
	Comm           [TASK_COMM_LEN]byte
	SocketID       uint64
	Tuple          Tuple
	ExtraData      uint32
	ExtraDataCount uint32
	TcpSeq         uint32
	ThreadTraceID  uint64
	Timestamp      uint64
	Direction      uint8
	MsgType        uint8
	SyscallLen     uint64
	DataSeq        uint64
	DataType       uint16
	DataLen        uint16
	Data           [BURST_DATA_BUF_SIZE]byte
}

type StackEvent struct {
	Pid         uint64
	TraceId     uint64
	Goid        uint64
	Ip          uint64
	Bp          uint64
	CallerIp    uint64
	CallerBp    uint64
	TimeNsStart uint64
	TimeNsEnd   uint64
	Nid         uint64
	Fpid        uint64
	Level       uint64
	Location    byte
}

type StackFunEvent struct {
	StackEvent StackEvent
	Uprobe     *tracer.Uprobe
	Level      int
	Pid        int
	Nid        int
}

func runEventsReader(name string, r *perf.Reader, ch chan<- Event, typ perfMapType) {
	for {
		rec, err := r.Read()
		if err != nil {
			if errors.Is(err, perf.ErrClosed) {
				break
			}
			continue
		}
		if rec.LostSamples > 0 {
			klog.Errorln(name, "lost samples:", rec.LostSamples)
			continue
		}
		var event Event

		switch typ {
		case perfMapTypeSocketEvents:
			//fmt.Println("perfMapTypeSocketEvents")
			// 假设 rec.RawSample 包含数据，类型为 []byte
			//rawData := rec.RawSample
			//fmt.Println("perfMapTypeSocketEvents2")
			//
			//// 创建一个 SocketDataBuffer 结构体实例
			//var buffer SocketDataBuffer
			//
			//// 创建一个字节缓冲区，并将数据填充到其中
			//reader := bytes.NewReader(rawData)
			//fmt.Println("perfMapTypeSocketEvents3")
			//fmt.Println(len(rawData))
			//// 使用 binary.Read 函数读取数据并解析为 SocketDataBuffer 结构体实例
			//if err := binary.Read(reader, binary.LittleEndian, &buffer); err != nil {
			//	fmt.Println(reader.Len())
			//	fmt.Println("Failed to read data:", err)
			//	continue
			//}
			//fmt.Println("perfMapTypeSocketEvents4")
			//
			//// 打印解析后的数据
			//fmt.Println("EventsNum:", buffer.EventsNum)
			//fmt.Println("Len:", buffer.Len)
			//
			//// 打印 char data 的内容
			//fmt.Printf("Data: %s\n", string(buffer.Data[:buffer.Len])) // 仅打印实际长度的数据

			//socketDataBuffer := rec.RawSample

			// 解析 __socket_data_buffer
			//buf := (*SocketDataBuffer)(unsafe.Pointer(&rec.RawSample[0])) //nolint:gosec
			//
			//// 获取 char data[32760];
			//socketData := (*SocketData)(unsafe.Pointer(&buf.data[0])) //nolint:gosec
			//// todo
			//fmt.Printf("socketData.DataType:%d \n", (socketData.data_type))
			//fmt.Printf("socketData.DataLen:%d \n", (socketData.data_len))
			//
			//// 解析C结构体中的data字段
			//dataSlice := C.GoBytes(unsafe.Pointer(&socketData.data[0]), C.int(socketData.data_len))
			//// 打印或处理包含的数据
			//fmt.Printf("socketData.Payload:%v \n", string(dataSlice))

			/*todo */
			//socketData := (*(*[128]byte)(unsafe.Pointer(&eventC.line)))
			//dataPtr := unsafe.Pointer(&buf.data[0])
			//socketData := (*SocketData)(dataPtr)

			//reader2 := bytes.NewBuffer(rec.RawSample)

			// 222222

			//fmt.Println("socketData.Pid:", socketData.pid)
			//fmt.Println("socketData.Tgid:", socketData.tgid)
			//fmt.Println("socketData.CoroutineID:", socketData.coroutine_id)
			//fmt.Println("socketData.Source:", socketData.source)
			//
			//fmt.Printf("socketData.Comm: %s \n", socketData.comm)
			//fmt.Printf("socketData.SocketID :%v \n", socketData.socket_id)
			//fmt.Println("socketData.Tuple:", socketData.Tuple)
			//fmt.Println("socketData.ExtraData:", socketData.ExtraData)
			//fmt.Println("socketData.ExtraDataCount:", socketData.ExtraDataCount)
			//fmt.Println("socketData.TCPSeq:", socketData.TcpSeq)
			//fmt.Println("socketData.ThreadTraceID:", socketData.ThreadTraceID)
			//fmt.Println("socketData.Timestamp:", socketData.Timestamp)
			//fmt.Println("socketData.Direction:", socketData.Direction)
			//fmt.Println("socketData.MsgType:", socketData.MsgType)
			//fmt.Println("socketData.SyscallLen:", socketData.SyscallLen)
			//fmt.Println("socketData.DataSeq:", socketData.DataSeq)

			//socketData := &SocketData{}
			//reader := bytes.NewBuffer(rec.RawSample)
			//if err := binary.Read(reader, binary.LittleEndian, v); err != nil {
			//	klog.Warningln("failed1 to read msg:", err)
			//	continue
			//}

			//
			//var data []byte
			//payload := reader.Bytes()
			//switch {
			//case v.Len == 0:
			//case v.Len > 32760:
			//	data = payload[:32760]
			//default:
			//	data = payload[:v.Len]
			//}
			//////data2 := data[:v.Len]
			////fmt.Println("perfMapTypeSocketEvents")
			//fmt.Println(v.EventsNum)
			//fmt.Println(v.Len)
			//fmt.Println(string(data))
			//
			//var data2 SocketData
			//reader2 := bytes.NewBuffer(data)
			//if err := binary.Read(reader2, binary.LittleEndian, data2); err != nil {
			//	klog.Warningln("failed2 to read msg:", err)
			//	continue
			//}
			//
			//fmt.Println(data2.Pid)
			//fmt.Println(data2.Tgid)

			//fmt.Println(string(v.Data))
			//continue
		case perfMapTypeL7Events:
			v := &l7Event{}
			reader := bytes.NewBuffer(rec.RawSample)
			if err := binary.Read(reader, binary.LittleEndian, v); err != nil {
				klog.Warningln("failed to read msg:", err)
				continue
			}
			//fmt.Println("v.TraceIdFrom")
			//fmt.Println(v.TraceIdFrom)
			//a := hex.EncodeToString(v.TraceIdFrom[:])
			//for _, b := range v.AssumedAppId {
			//	fmt.Printf("v.AssumedAppId- %02\n", b)
			//}
			//fmt.Println(a)

			payload := reader.Bytes()
			req := &l7.RequestData{
				Protocol:     l7.Protocol(v.Protocol),
				Status:       l7.Status(v.Status),
				Duration:     time.Duration(v.Duration),
				Method:       l7.Method(v.Method),
				StatementId:  v.StatementId,
				TraceId:      v.TraceId,
				TraceStart:   v.TraceStart,
				TraceEnd:     v.TraceEnd,
				EventCount:   v.EventCount,
				AssumedAppId: hex.EncodeToString(v.AssumedAppId[:]),
				SpanId:       hex.EncodeToString(v.SpanId[:]),
			}
			if v.TraceEnd == 1 {
				req.ParentSpanContext.TraceIdFrom = hex.EncodeToString(v.TraceIdFrom[:])
				req.ParentSpanContext.CalledId = hex.EncodeToString(v.CalledId[:])
				req.ParentSpanContext.InstanceIdFrom = hex.EncodeToString(v.InstanceIdFrom[:])
				req.ParentSpanContext.AppIdFrom = hex.EncodeToString(v.AppIdFrom[:])
				req.ParentSpanContext.SpanIdFrom = hex.EncodeToString(v.SpanIdFrom[:])
			}
			switch {
			case v.PayloadSize == 0:
			case v.PayloadSize > MaxPayloadSize:
				req.Payload = payload[:MaxPayloadSize]
			default:
				req.Payload = payload[:v.PayloadSize]
			}
			//fmt.Println("==========")
			//fmt.Println("req.Payload:", string(req.Payload))
			//fmt.Println("==========")
			event = Event{Type: EventTypeL7Request, Pid: v.Pid, Fd: v.Fd, Timestamp: v.ConnectionTimestamp, L7Request: req}
		case perfMapTypeFileEvents:
			v := &fileEvent{}
			if err := binary.Read(bytes.NewBuffer(rec.RawSample), binary.LittleEndian, v); err != nil {
				klog.Warningln("failed to read msg:", err)
				continue
			}
			event = Event{Type: v.Type, Pid: v.Pid, Fd: v.Fd}
		case perfMapTypeProcEvents:
			v := &procEvent{}
			if err := binary.Read(bytes.NewBuffer(rec.RawSample), binary.LittleEndian, v); err != nil {
				klog.Warningln("failed to read msg:", err)
				continue
			}
			event = Event{Type: v.Type, Reason: EventReason(v.Reason), Pid: v.Pid}
		case perfMapTypeTCPEvents:
			v := &tcpEvent{}
			if err := binary.Read(bytes.NewBuffer(rec.RawSample), binary.LittleEndian, v); err != nil {
				klog.Warningln("failed to read msg:", err)
				continue
			}
			event = Event{
				Type:      v.Type,
				Pid:       v.Pid,
				SrcAddr:   ipPort(v.SAddr, v.SPort),
				DstAddr:   ipPort(v.DAddr, v.DPort),
				Fd:        v.Fd,
				Timestamp: v.Timestamp,
			}
		case perfMapTypeEventQueue:
			v := &StackEvent{}
			if err := binary.Read(bytes.NewBuffer(rec.RawSample), binary.LittleEndian, v); err != nil {
				klog.Warningln("failed to read msg:", err)
				continue
			}

			event = Event{
				Type:       EventTypeFunEnt,
				StackEvent: v,
			}
		default:
			continue
		}

		ch <- event
	}
}

func ipPort(ip [16]byte, port uint16) netaddr.IPPort {
	i, _ := netaddr.FromStdIP(ip[:])
	return netaddr.IPPortFrom(i, port)
}

func (t *Tracer) InitKProcInfo(pid uint32, insID utils.ID) error {

	info := tracer.EbpfProcInfo{}
	info.InstanceId = insID.HashtVal
	// 获取内存地址
	allocDetails, err := tracer.Allocate(int(pid))
	if err == nil && allocDetails != nil {
		info.StartAddr = allocDetails.StartAddr
		info.EndAddr = allocDetails.EndAddr
	}
	//klog.Infoln("Major:", major)
	//klog.Infoln("Minor:", minor)
	//klog.Infoln("Revision:", revision)
	//klog.Infoln("goVersion", goVersion)
	//klog.Infoln("info.StartAddr", info.StartAddr)
	//klog.Infoln("info.EndAddr", info.EndAddr)
	_, err = tracer.UpdateProcInfoToMap(t.collection, pid, info)
	if err != nil {
		klog.Error("failed to update program info", err)
	}
	return err
}