1 files changed, 216 insertions, 0 deletions
diff --git a/vendor/github.com/cilium/ebpf/marshalers.go b/vendor/github.com/cilium/ebpf/marshalers.go
new file mode 100644
index 000000000..3ea1021a8
--- /dev/null
+++ b/vendor/github.com/cilium/ebpf/marshalers.go
@@ -0,0 +1,216 @@
+package ebpf
+
+import (
+	"bytes"
+	"encoding"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"reflect"
+	"runtime"
+	"unsafe"
+
+	"github.com/cilium/ebpf/internal"
+)
+
+// marshalPtr converts an arbitrary value into a pointer suitable
+// to be passed to the kernel.
+//
+// As an optimization, it returns the original value if it is an
+// unsafe.Pointer.
+func marshalPtr(data interface{}, length int) (internal.Pointer, error) {
+	if ptr, ok := data.(unsafe.Pointer); ok {
+		return internal.NewPointer(ptr), nil
+	}
+
+	buf, err := marshalBytes(data, length)
+	if err != nil {
+		return internal.Pointer{}, err
+	}
+
+	return internal.NewSlicePointer(buf), nil
+}
+
+// marshalBytes converts an arbitrary value into a byte buffer.
+//
+// Prefer using Map.marshalKey and Map.marshalValue if possible, since
+// those have special cases that allow more types to be encoded.
+//
+// Returns an error if the given value isn't representable in exactly
+// length bytes.
+func marshalBytes(data interface{}, length int) (buf []byte, err error) {
+	switch value := data.(type) {
+	case encoding.BinaryMarshaler:
+		buf, err = value.MarshalBinary()
+	case string:
+		buf = []byte(value)
+	case []byte:
+		buf = value
+	case unsafe.Pointer:
+		err = errors.New("can't marshal from unsafe.Pointer")
+	case Map, *Map, Program, *Program:
+		err = fmt.Errorf("can't marshal %T", value)
+	default:
+		var wr bytes.Buffer
+		err = binary.Write(&wr, internal.NativeEndian, value)
+		if err != nil {
+			err = fmt.Errorf("encoding %T: %v", value, err)
+		}
+		buf = wr.Bytes()
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	if len(buf) != length {
+		return nil, fmt.Errorf("%T doesn't marshal to %d bytes", data, length)
+	}
+	return buf, nil
+}
+
+func makeBuffer(dst interface{}, length int) (internal.Pointer, []byte) {
+	if ptr, ok := dst.(unsafe.Pointer); ok {
+		return internal.NewPointer(ptr), nil
+	}
+
+	buf := make([]byte, length)
+	return internal.NewSlicePointer(buf), buf
+}
+
+// unmarshalBytes converts a byte buffer into an arbitrary value.
+//
+// Prefer using Map.unmarshalKey and Map.unmarshalValue if possible, since
+// those have special cases that allow more types to be encoded.
+func unmarshalBytes(data interface{}, buf []byte) error {
+	switch value := data.(type) {
+	case unsafe.Pointer:
+		sh := &reflect.SliceHeader{
+			Data: uintptr(value),
+			Len:  len(buf),
+			Cap:  len(buf),
+		}
+
+		dst := *(*[]byte)(unsafe.Pointer(sh))
+		copy(dst, buf)
+		runtime.KeepAlive(value)
+		return nil
+	case Map, *Map, Program, *Program:
+		return fmt.Errorf("can't unmarshal into %T", value)
+	case encoding.BinaryUnmarshaler:
+		return value.UnmarshalBinary(buf)
+	case *string:
+		*value = string(buf)
+		return nil
+	case *[]byte:
+		*value = buf
+		return nil
+	case string:
+		return errors.New("require pointer to string")
+	case []byte:
+		return errors.New("require pointer to []byte")
+	default:
+		rd := bytes.NewReader(buf)
+		if err := binary.Read(rd, internal.NativeEndian, value); err != nil {
+			return fmt.Errorf("decoding %T: %v", value, err)
+		}
+		return nil
+	}
+}
+
+// marshalPerCPUValue encodes a slice containing one value per
+// possible CPU into a buffer of bytes.
+//
+// Values are initialized to zero if the slice has less elements than CPUs.
+//
+// slice must have a type like []elementType.
+func marshalPerCPUValue(slice interface{}, elemLength int) (internal.Pointer, error) {
+	sliceType := reflect.TypeOf(slice)
+	if sliceType.Kind() != reflect.Slice {
+		return internal.Pointer{}, errors.New("per-CPU value requires slice")
+	}
+
+	possibleCPUs, err := internal.PossibleCPUs()
+	if err != nil {
+		return internal.Pointer{}, err
+	}
+
+	sliceValue := reflect.ValueOf(slice)
+	sliceLen := sliceValue.Len()
+	if sliceLen > possibleCPUs {
+		return internal.Pointer{}, fmt.Errorf("per-CPU value exceeds number of CPUs")
+	}
+
+	alignedElemLength := align(elemLength, 8)
+	buf := make([]byte, alignedElemLength*possibleCPUs)
+
+	for i := 0; i < sliceLen; i++ {
+		elem := sliceValue.Index(i).Interface()
+		elemBytes, err := marshalBytes(elem, elemLength)
+		if err != nil {
+			return internal.Pointer{}, err
+		}
+
+		offset := i * alignedElemLength
+		copy(buf[offset:offset+elemLength], elemBytes)
+	}
+
+	return internal.NewSlicePointer(buf), nil
+}
+
+// unmarshalPerCPUValue decodes a buffer into a slice containing one value per
+// possible CPU.
+//
+// valueOut must have a type like *[]elementType
+func unmarshalPerCPUValue(slicePtr interface{}, elemLength int, buf []byte) error {
+	slicePtrType := reflect.TypeOf(slicePtr)
+	if slicePtrType.Kind() != reflect.Ptr || slicePtrType.Elem().Kind() != reflect.Slice {
+		return fmt.Errorf("per-cpu value requires pointer to slice")
+	}
+
+	possibleCPUs, err := internal.PossibleCPUs()
+	if err != nil {
+		return err
+	}
+
+	sliceType := slicePtrType.Elem()
+	slice := reflect.MakeSlice(sliceType, possibleCPUs, possibleCPUs)
+
+	sliceElemType := sliceType.Elem()
+	sliceElemIsPointer := sliceElemType.Kind() == reflect.Ptr
+	if sliceElemIsPointer {
+		sliceElemType = sliceElemType.Elem()
+	}
+
+	step := len(buf) / possibleCPUs
+	if step < elemLength {
+		return fmt.Errorf("per-cpu element length is larger than available data")
+	}
+	for i := 0; i < possibleCPUs; i++ {
+		var elem interface{}
+		if sliceElemIsPointer {
+			newElem := reflect.New(sliceElemType)
+			slice.Index(i).Set(newElem)
+			elem = newElem.Interface()
+		} else {
+			elem = slice.Index(i).Addr().Interface()
+		}
+
+		// Make a copy, since unmarshal can hold on to itemBytes
+		elemBytes := make([]byte, elemLength)
+		copy(elemBytes, buf[:elemLength])
+
+		err := unmarshalBytes(elem, elemBytes)
+		if err != nil {
+			return fmt.Errorf("cpu %d: %w", i, err)
+		}
+
+		buf = buf[step:]
+	}
+
+	reflect.ValueOf(slicePtr).Elem().Set(slice)
+	return nil
+}
+
+func align(n, alignment int) int {
+	return (int(n) + alignment - 1) / alignment * alignment
+}