Bump Custom Labels ABI to v1 (for Node support)

Author: umanwizard

interpreter/customlabels/customlabels.go

@@ -18,10 +18,10 @@ import (
 
 const (
 	abiVersionExport = "custom_labels_abi_version"
-	tlsExport        = "custom_labels_thread_local_data"
+	tlsExport        = "custom_labels_current_set"
 )
 
-var dsoRegex = regexp.MustCompile(`.*/libcustomlabels.*\.so`)
+var dsoRegex = regexp.MustCompile(`.*/libcustomlabels.*\.so|.*/customlabels\.node`)
 
 type data struct {
 	abiVersionElfVA libpf.Address
@@ -125,12 +125,14 @@ type instance struct {
 func (d data) Attach(ebpf interpreter.EbpfHandler, pid libpf.PID,
 	bias libpf.Address, rm remotememory.RemoteMemory) (interpreter.Instance, error) {
 
-	abiVersionPtr := rm.Ptr(bias + d.abiVersionElfVA)
-	abiVersion := rm.Uint32(abiVersionPtr)
+	abiVersion, err := rm.Uint32Checked(bias + d.abiVersionElfVA)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read custom labels ABI version: %w", err)
+	}
 
-	if abiVersion != 0 {
+	if abiVersion != 1 {
 		return nil, fmt.Errorf("unsupported custom labels ABI version: %d"+
-			" (only 0 is supported)", abiVersion)
+			" (only 1 is supported)", abiVersion)
 	}
 
 	var tlsOffset uint64

remotememory/remotememory.go

@@ -71,6 +71,15 @@ func (rm RemoteMemory) Uint32(addr libpf.Address) uint32 {
 	return binary.LittleEndian.Uint32(buf[:])
 }
 
+// Uint32Checked reads a 32-bit unsigned integer from remote memory
+func (rm RemoteMemory) Uint32Checked(addr libpf.Address) (uint32, error) {
+	var buf [4]byte
+	if err := rm.Read(addr, buf[:]); err != nil {
+		return 0, err
+	}
+	return binary.LittleEndian.Uint32(buf[:]), nil
+}
+
 // Uint64 reads a 64-bit unsigned integer from remote memory
 func (rm RemoteMemory) Uint64(addr libpf.Address) uint64 {
 	var buf [8]byte

support/ebpf/interpreter_dispatcher.ebpf.c

@@ -436,24 +436,36 @@ bool get_native_custom_labels(struct pt_regs *ctx, UnwindState *state, void *dat
   u64 offset = tsd_base + proc->tls_offset;
   DEBUG_PRINT("native custom labels data at 0x%llx", offset);
 
-  NativeCustomLabelsThreadLocalData tls;
+  NativeCustomLabelsSet *p_current_set;
   int err;
-  if ((err = bpf_probe_read_user(&tls, sizeof(tls), (void *)(offset)))) {
+  if ((err = bpf_probe_read_user(&p_current_set, sizeof(void *), (void *)(offset)))) {
+    increment_metric(metricID_UnwindNativeCustomLabelsErrReadData);
+    DEBUG_PRINT("Failed to read custom labels current set pointer: %d", err);
+    return false;
+  }
+
+  if (!p_current_set) {
+    DEBUG_PRINT("Null labelset");
+    return true;
+  }
+
+  NativeCustomLabelsSet current_set;
+  if ((err = bpf_probe_read_user(&current_set, sizeof(current_set), p_current_set))) {
     increment_metric(metricID_UnwindNativeCustomLabelsErrReadData);
     DEBUG_PRINT("Failed to read custom labels data: %d", err);
     return false;
   }
 
-  DEBUG_PRINT("Native custom labels count: %lu", tls.count);
+  DEBUG_PRINT("Native custom labels count: %lu", current_set.count);
 
-  int remaining = MIN(tls.count, MAX_CUSTOM_LABELS);
+  int remaining = MIN(current_set.count, MAX_CUSTOM_LABELS);
   int i = 0;
   int ct = 0;
 
   while (remaining) {
     if (i >= MAX_CUSTOM_LABELS)
       break;
-    NativeCustomLabel *lbl_ptr = tls.storage + i;
+    NativeCustomLabel *lbl_ptr = current_set.storage + i;
     ++i;
     NativeCustomLabel lbl;
     if ((err = bpf_probe_read_user(&lbl, sizeof(lbl), (void *)(lbl_ptr)))) {

support/ebpf/tracer.ebpf.debug.amd64

@@ -577,7 +577,8 @@ typedef struct NativeCustomLabel {
 typedef struct NativeCustomLabelsThreadLocalData {
   NativeCustomLabel *storage;
   size_t count;
-} NativeCustomLabelsThreadLocalData;
+  size_t capacity;
+} NativeCustomLabelsSet;
 
 // Container for a stack trace
 typedef struct Trace {