Merge pull request #160 from parca-dev/fix-str

Fix string termination

Author: gnurizen

parcagpu/parcagpu.go

@@ -15,6 +15,7 @@ import (
 	"go.opentelemetry.io/ebpf-profiler/host"
 	"go.opentelemetry.io/ebpf-profiler/libpf"
 	"go.opentelemetry.io/ebpf-profiler/support"
+	"go.opentelemetry.io/ebpf-profiler/util"
 )
 
 type mapKey struct {
@@ -93,7 +94,7 @@ func prepTrace(tr *host.Trace, ev *kernelTimingEvent) {
 	}
 	if len(ev.kernelName) > 0 {
 		// TODO: is there a better way to pass this through?
-		tr.CustomLabels["_temp_cuda_kernel"] = string(ev.kernelName[:])
+		tr.CustomLabels["_temp_cuda_kernel"] = util.GoString(ev.kernelName[:])
 		// ConvertTrace will add a pseudo-frame for the kernel.
 		tr.Frames = append([]host.Frame{{
 			Type: libpf.CUDAKernelFrame,

tracer/tracer.go

@@ -6,7 +6,6 @@ package tracer // import "go.opentelemetry.io/ebpf-profiler/tracer"
 
 import (
 	"bufio"
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -178,15 +177,6 @@ type progLoaderHelper struct {
 	noTailCallTarget bool
 }
 
-// Convert a C-string to Go string.
-func goString(cstr []byte) string {
-	index := bytes.IndexByte(cstr, byte(0))
-	if index < 0 {
-		index = len(cstr)
-	}
-	return strings.Clone(unsafe.String(unsafe.SliceData(cstr), index))
-}
-
 // schedProcessFreeHookName returns the name of the tracepoint hook to use.
 // This function requires that only one of (schedProcessFreeV1, schedProcessFreeV2)
 // be present in progNames.
@@ -916,7 +906,7 @@ func (t *Tracer) loadBpfTrace(raw []byte, cpu int) *host.Trace {
 	pid := libpf.PID(ptr.Pid)
 	procMeta := t.processManager.MetaForPID(pid)
 	trace := &host.Trace{
-		Comm:             goString(ptr.Comm[:]),
+		Comm:             util.GoString(ptr.Comm[:]),
 		ExecutablePath:   procMeta.Executable,
 		ContainerID:      procMeta.ContainerID,
 		ProcessName:      procMeta.Name,
@@ -947,8 +937,8 @@ func (t *Tracer) loadBpfTrace(raw []byte, cpu int) *host.Trace {
 		trace.CustomLabels = make(map[string]string, clLen)
 		for i := 0; i < clLen; i++ {
 			lbl := ptr.Custom_labels.Labels[i]
-			key := goString(lbl.Key[:])
-			val := goString(lbl.Val[:])
+			key := util.GoString(lbl.Key[:])
+			val := util.GoString(lbl.Val[:])
 			trace.CustomLabels[key] = val
 		}
 	}

util/util.go

@@ -7,10 +7,12 @@ import (
 	"bytes"
 	"fmt"
 	"math/bits"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"unicode"
 	"unicode/utf8"
+	"unsafe"
 
 	"github.com/cilium/ebpf"
 	"github.com/cilium/ebpf/asm"
@@ -181,3 +183,12 @@ func ProgArrayReferences(perfTailCallMapFD int, insns asm.Instructions) []int {
 	}
 	return insNos
 }
+
+// Convert a C-string to Go string.
+func GoString(cstr []byte) string {
+	index := bytes.IndexByte(cstr, byte(0))
+	if index < 0 {
+		index = len(cstr)
+	}
+	return strings.Clone(unsafe.String(unsafe.SliceData(cstr), index))
+}