vendor: update tcptracer-bpf and gobpf

This includes:

- https://github.com/iovisor/gobpf/pull/70
  perf: close go channels idiomatically

- https://github.com/iovisor/gobpf/pull/70
  close channels on the sender side & fix closing race

- https://github.com/weaveworks/tcptracer-bpf/pull/50
  vendor: update gobpf

vendor/github.com/weaveworks/tcptracer-bpf/pkg/tracer/tracer.go

@@ -79,10 +79,19 @@ func NewTracer(cb Callback) (*Tracer, error) {
 		for {
 			select {
 			case <-stopChan:
+				// On stop, stopChan will be closed but the other channels will
+				// also be closed shortly after. The select{} has no priorities,
+				// therefore, the "ok" value must be checked below.
 				return
-			case data := <-channelV4:
+			case data, ok := <-channelV4:
+				if !ok {
+					return // see explanation above
+				}
 				cb.TCPEventV4(tcpV4ToGo(&data))
-			case lost := <-lostChanV4:
+			case lost, ok := <-lostChanV4:
+				if !ok {
+					return // see explanation above
+				}
 				cb.LostV4(lost)
 			}
 		}
@@ -93,9 +102,15 @@ func NewTracer(cb Callback) (*Tracer, error) {
 			select {
 			case <-stopChan:
 				return
-			case data := <-channelV6:
+			case data, ok := <-channelV6:
+				if !ok {
+					return // see explanation above
+				}
 				cb.TCPEventV6(tcpV6ToGo(&data))
-			case lost := <-lostChanV6:
+			case lost, ok := <-lostChanV6:
+				if !ok {
+					return // see explanation above
+				}
 				cb.LostV6(lost)
 			}
 		}

vendor/github.com/weaveworks/tcptracer-bpf/vendor/github.com/iovisor/gobpf/elf/elf.go

@@ -515,6 +515,7 @@ func (b *Module) Load(parameters map[string]SectionParams) error {
 			isCgroupSkb := strings.HasPrefix(secName, "cgroup/skb")
 			isCgroupSock := strings.HasPrefix(secName, "cgroup/sock")
 			isSocketFilter := strings.HasPrefix(secName, "socket")
+			isTracepoint := strings.HasPrefix(secName, "tracepoint/")
 
 			var progType uint32
 			switch {
@@ -528,9 +529,11 @@ func (b *Module) Load(parameters map[string]SectionParams) error {
 				progType = uint32(C.BPF_PROG_TYPE_CGROUP_SOCK)
 			case isSocketFilter:
 				progType = uint32(C.BPF_PROG_TYPE_SOCKET_FILTER)
+			case isTracepoint:
+				progType = uint32(C.BPF_PROG_TYPE_TRACEPOINT)
 			}
 
-			if isKprobe || isKretprobe || isCgroupSkb || isCgroupSock || isSocketFilter {
+			if isKprobe || isKretprobe || isCgroupSkb || isCgroupSock || isSocketFilter || isTracepoint {
 				rdata, err := rsection.Data()
 				if err != nil {
 					return err
@@ -579,6 +582,12 @@ func (b *Module) Load(parameters map[string]SectionParams) error {
 						insns: insns,
 						fd:    int(progFd),
 					}
+				case isTracepoint:
+					b.tracepointPrograms[secName] = &TracepointProgram{
+						Name:  secName,
+						insns: insns,
+						fd:    int(progFd),
+					}
 				}
 			}
 		}
@@ -596,6 +605,7 @@ func (b *Module) Load(parameters map[string]SectionParams) error {
 		isCgroupSkb := strings.HasPrefix(secName, "cgroup/skb")
 		isCgroupSock := strings.HasPrefix(secName, "cgroup/sock")
 		isSocketFilter := strings.HasPrefix(secName, "socket")
+		isTracepoint := strings.HasPrefix(secName, "tracepoint/")
 
 		var progType uint32
 		switch {
@@ -609,9 +619,11 @@ func (b *Module) Load(parameters map[string]SectionParams) error {
 			progType = uint32(C.BPF_PROG_TYPE_CGROUP_SOCK)
 		case isSocketFilter:
 			progType = uint32(C.BPF_PROG_TYPE_SOCKET_FILTER)
+		case isTracepoint:
+			progType = uint32(C.BPF_PROG_TYPE_TRACEPOINT)
 		}
 
-		if isKprobe || isKretprobe || isCgroupSkb || isCgroupSock || isSocketFilter {
+		if isKprobe || isKretprobe || isCgroupSkb || isCgroupSock || isSocketFilter || isTracepoint {
 			data, err := section.Data()
 			if err != nil {
 				return err
@@ -655,6 +667,12 @@ func (b *Module) Load(parameters map[string]SectionParams) error {
 					insns: insns,
 					fd:    int(progFd),
 				}
+			case isTracepoint:
+				b.tracepointPrograms[secName] = &TracepointProgram{
+					Name:  secName,
+					insns: insns,
+					fd:    int(progFd),
+				}
 			}
 		}
 	}

vendor/github.com/weaveworks/tcptracer-bpf/vendor/github.com/iovisor/gobpf/elf/module.go

@@ -96,11 +96,12 @@ type Module struct {
 	fileReader io.ReaderAt
 	file       *elf.File
 
-	log            []byte
-	maps           map[string]*Map
-	probes         map[string]*Kprobe
-	cgroupPrograms map[string]*CgroupProgram
-	socketFilters  map[string]*SocketFilter
+	log                []byte
+	maps               map[string]*Map
+	probes             map[string]*Kprobe
+	cgroupPrograms     map[string]*CgroupProgram
+	socketFilters      map[string]*SocketFilter
+	tracepointPrograms map[string]*TracepointProgram
 }
 
 // Kprobe represents a kprobe or kretprobe and has to be declared
@@ -134,13 +135,22 @@ type SocketFilter struct {
 	fd    int
 }
 
+// TracepointProgram represents a tracepoint program
+type TracepointProgram struct {
+	Name  string
+	insns *C.struct_bpf_insn
+	fd    int
+	efd   int
+}
+
 func NewModule(fileName string) *Module {
 	return &Module{
-		fileName:       fileName,
-		probes:         make(map[string]*Kprobe),
-		cgroupPrograms: make(map[string]*CgroupProgram),
-		socketFilters:  make(map[string]*SocketFilter),
-		log:            make([]byte, 65536),
+		fileName:           fileName,
+		probes:             make(map[string]*Kprobe),
+		cgroupPrograms:     make(map[string]*CgroupProgram),
+		socketFilters:      make(map[string]*SocketFilter),
+		tracepointPrograms: make(map[string]*TracepointProgram),
+		log:                make([]byte, 65536),
 	}
 }
 
@@ -186,6 +196,22 @@ func writeKprobeEvent(probeType, eventName, funcName, maxactiveStr string) (int,
 	return kprobeId, nil
 }
 
+func perfEventOpenTracepoint(id int, progFd int) (int, error) {
+	efd, err := C.perf_event_open_tracepoint(C.int(id), -1 /* pid */, 0 /* cpu */, -1 /* group_fd */, C.PERF_FLAG_FD_CLOEXEC)
+	if efd < 0 {
+		return -1, fmt.Errorf("perf_event_open error: %v", err)
+	}
+
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, uintptr(efd), C.PERF_EVENT_IOC_ENABLE, 0); err != 0 {
+		return -1, fmt.Errorf("error enabling perf event: %v", err)
+	}
+
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, uintptr(efd), C.PERF_EVENT_IOC_SET_BPF, uintptr(progFd)); err != 0 {
+		return -1, fmt.Errorf("error attaching bpf program to perf event: %v", err)
+	}
+	return int(efd), nil
+}
+
 // EnableKprobe enables a kprobe/kretprobe identified by secName.
 // For kretprobes, you can configure the maximum number of instances
 // of the function that can be probed simultaneously with maxactive.
@@ -222,22 +248,43 @@ func (b *Module) EnableKprobe(secName string, maxactive int) error {
 		return err
 	}
 
-	efd := C.perf_event_open_tracepoint(C.int(kprobeId), -1 /* pid */, 0 /* cpu */, -1 /* group_fd */, C.PERF_FLAG_FD_CLOEXEC)
-	if efd < 0 {
-		return fmt.Errorf("perf_event_open for kprobe error")
+	probe.efd, err = perfEventOpenTracepoint(kprobeId, progFd)
+	return err
+}
+
+func writeTracepointEvent(category, name string) (int, error) {
+	tracepointIdFile := fmt.Sprintf("/sys/kernel/debug/tracing/events/%s/%s/id", category, name)
+	tracepointIdBytes, err := ioutil.ReadFile(tracepointIdFile)
+	if err != nil {
+		return -1, fmt.Errorf("cannot read tracepoint id %q: %v", tracepointIdFile, err)
 	}
 
-	_, _, err2 := syscall.Syscall(syscall.SYS_IOCTL, uintptr(efd), C.PERF_EVENT_IOC_ENABLE, 0)
-	if err2 != 0 {
-		return fmt.Errorf("error enabling perf event: %v", err2)
+	tracepointId, err := strconv.Atoi(strings.TrimSpace(string(tracepointIdBytes)))
+	if err != nil {
+		return -1, fmt.Errorf("invalid tracepoint id: %v\n", err)
 	}
 
-	_, _, err2 = syscall.Syscall(syscall.SYS_IOCTL, uintptr(efd), C.PERF_EVENT_IOC_SET_BPF, uintptr(progFd))
-	if err2 != 0 {
-		return fmt.Errorf("error enabling perf event: %v", err2)
+	return tracepointId, nil
+}
+
+func (b *Module) EnableTracepoint(secName string) error {
+	prog, ok := b.tracepointPrograms[secName]
+	if !ok {
+		return fmt.Errorf("no such tracepoint program %q", secName)
 	}
-	probe.efd = int(efd)
-	return nil
+	progFd := prog.fd
+
+	tracepointGroup := strings.SplitN(secName, "/", 3)
+	category := tracepointGroup[1]
+	name := tracepointGroup[2]
+
+	tracepointId, err := writeTracepointEvent(category, name)
+	if err != nil {
+		return err
+	}
+
+	prog.efd, err = perfEventOpenTracepoint(tracepointId, progFd)
+	return err
 }
 
 // IterKprobes returns a channel that emits the kprobes that included in the
@@ -277,6 +324,17 @@ func (b *Module) IterCgroupProgram() <-chan *CgroupProgram {
 	return ch
 }
 
+func (b *Module) IterTracepointProgram() <-chan *TracepointProgram {
+	ch := make(chan *TracepointProgram)
+	go func() {
+		for name := range b.tracepointPrograms {
+			ch <- b.tracepointPrograms[name]
+		}
+		close(ch)
+	}()
+	return ch
+}
+
 func (b *Module) CgroupProgram(name string) *CgroupProgram {
 	return b.cgroupPrograms[name]
 }
@@ -412,6 +470,21 @@ func (b *Module) closeProbes() error {
 	return nil
 }
 
+func (b *Module) closeTracepointPrograms() error {
+	for _, program := range b.tracepointPrograms {
+		if program.efd != -1 {
+			if err := syscall.Close(program.efd); err != nil {
+				return fmt.Errorf("error closing perf event fd: %v", err)
+			}
+			program.efd = -1
+		}
+		if err := syscall.Close(program.fd); err != nil {
+			return fmt.Errorf("error closing tracepoint program fd: %v", err)
+		}
+	}
+	return nil
+}
+
 func (b *Module) closeCgroupPrograms() error {
 	for _, program := range b.cgroupPrograms {
 		if err := syscall.Close(program.fd); err != nil {
@@ -490,6 +563,9 @@ func (b *Module) CloseExt(options map[string]CloseOptions) error {
 	if err := b.closeCgroupPrograms(); err != nil {
 		return err
 	}
+	if err := b.closeTracepointPrograms(); err != nil {
+		return err
+	}
 	if err := b.closeSocketFilters(); err != nil {
 		return err
 	}

vendor/github.com/weaveworks/tcptracer-bpf/vendor/github.com/iovisor/gobpf/elf/perf.go

@@ -109,7 +109,7 @@ type PerfMap struct {
 	pageCount    int
 	receiverChan chan []byte
 	lostChan     chan uint64
-	pollStop     chan bool
+	pollStop     chan struct{}
 	timestamp    func(*[]byte) uint64
 }
 
@@ -125,6 +125,9 @@ func InitPerfMap(b *Module, mapName string, receiverChan chan []byte, lostChan c
 	if !ok {
 		return nil, fmt.Errorf("no map with name %s", mapName)
 	}
+	if receiverChan == nil {
+		return nil, fmt.Errorf("receiverChan is nil")
+	}
 	// Maps are initialized in b.Load(), nothing to do here
 	return &PerfMap{
 		name:         mapName,
@@ -132,7 +135,7 @@ func InitPerfMap(b *Module, mapName string, receiverChan chan []byte, lostChan c
 		pageCount:    m.pageCount,
 		receiverChan: receiverChan,
 		lostChan:     lostChan,
-		pollStop:     make(chan bool),
+		pollStop:     make(chan struct{}),
 	}, nil
 }
 
@@ -163,6 +166,13 @@ func (pm *PerfMap) PollStart() {
 		pageSize := os.Getpagesize()
 		state := C.struct_read_state{}
 
+		defer func() {
+			close(pm.receiverChan)
+			if pm.lostChan != nil {
+				close(pm.lostChan)
+			}
+		}()
+
 		for {
 			select {
 			case <-pm.pollStop:
@@ -208,7 +218,11 @@ func (pm *PerfMap) PollStart() {
 							}
 						case C.PERF_RECORD_LOST:
 							if pm.lostChan != nil {
-								pm.lostChan <- lost.Lost
+								select {
+								case pm.lostChan <- lost.Lost:
+								case <-pm.pollStop:
+									return
+								}
 							}
 						default:
 							// ignore unknown events
@@ -226,7 +240,11 @@ func (pm *PerfMap) PollStart() {
 						// elements also must not be processed now.
 						break harvestLoop
 					}
-					pm.receiverChan <- incoming.bytesArray[0]
+					select {
+					case pm.receiverChan <- incoming.bytesArray[0]:
+					case <-pm.pollStop:
+						return
+					}
 					// remove first element
 					incoming.bytesArray = incoming.bytesArray[1:]
 				}
@@ -238,10 +256,11 @@ func (pm *PerfMap) PollStart() {
 	}()
 }
 
-// PollStop stops the goroutine that polls the perf event map. Make
-// sure to close the receiverChan only *after* calling PollStop.
+// PollStop stops the goroutine that polls the perf event map.
+// Callers must not close receiverChan or lostChan: they will be automatically
+// closed on the sender side.
 func (pm *PerfMap) PollStop() {
-	pm.pollStop <- true
+	close(pm.pollStop)
 }
 
 func perfEventPoll(fds []C.int) error {

vendor/manifest

@@ -1020,7 +1020,7 @@
 			"importpath": "github.com/weaveworks/tcptracer-bpf",
 			"repository": "https://github.com/weaveworks/tcptracer-bpf",
 			"vcs": "git",
-			"revision": "53a889d82fbd8a4fc4ef3f0013a9f88a3e9f4ccc",
+			"revision": "e080bd747dc6b62d4ed3ed2b7f0be4801bef8faf",
 			"branch": "master",
 			"notests": true
 		},