GoToSocial/vendor/github.com/cilium/ebpf/map.go

1189 lines
30 KiB
Go

package ebpf
import (
"errors"
"fmt"
"io"
"path/filepath"
"reflect"
"strings"
"github.com/cilium/ebpf/internal"
"github.com/cilium/ebpf/internal/btf"
"github.com/cilium/ebpf/internal/unix"
)
// Errors returned by Map and MapIterator methods.
var (
ErrKeyNotExist = errors.New("key does not exist")
ErrKeyExist = errors.New("key already exists")
ErrIterationAborted = errors.New("iteration aborted")
)
// MapOptions control loading a map into the kernel.
type MapOptions struct {
// The base path to pin maps in if requested via PinByName.
// Existing maps will be re-used if they are compatible, otherwise an
// error is returned.
PinPath string
}
// MapID represents the unique ID of an eBPF map
type MapID uint32
// MapSpec defines a Map.
type MapSpec struct {
// Name is passed to the kernel as a debug aid. Must only contain
// alpha numeric and '_' characters.
Name string
Type MapType
KeySize uint32
ValueSize uint32
MaxEntries uint32
Flags uint32
// Automatically pin and load a map from MapOptions.PinPath.
// Generates an error if an existing pinned map is incompatible with the MapSpec.
Pinning PinType
// Specify numa node during map creation
// (effective only if unix.BPF_F_NUMA_NODE flag is set,
// which can be imported from golang.org/x/sys/unix)
NumaNode uint32
// The initial contents of the map. May be nil.
Contents []MapKV
// Whether to freeze a map after setting its initial contents.
Freeze bool
// InnerMap is used as a template for ArrayOfMaps and HashOfMaps
InnerMap *MapSpec
// The BTF associated with this map.
BTF *btf.Map
}
func (ms *MapSpec) String() string {
return fmt.Sprintf("%s(keySize=%d, valueSize=%d, maxEntries=%d, flags=%d)", ms.Type, ms.KeySize, ms.ValueSize, ms.MaxEntries, ms.Flags)
}
// Copy returns a copy of the spec.
//
// MapSpec.Contents is a shallow copy.
func (ms *MapSpec) Copy() *MapSpec {
if ms == nil {
return nil
}
cpy := *ms
cpy.Contents = make([]MapKV, len(ms.Contents))
copy(cpy.Contents, ms.Contents)
cpy.InnerMap = ms.InnerMap.Copy()
return &cpy
}
// MapKV is used to initialize the contents of a Map.
type MapKV struct {
Key interface{}
Value interface{}
}
func (ms *MapSpec) checkCompatibility(m *Map) error {
switch {
case m.typ != ms.Type:
return fmt.Errorf("expected type %v, got %v", ms.Type, m.typ)
case m.keySize != ms.KeySize:
return fmt.Errorf("expected key size %v, got %v", ms.KeySize, m.keySize)
case m.valueSize != ms.ValueSize:
return fmt.Errorf("expected value size %v, got %v", ms.ValueSize, m.valueSize)
case m.maxEntries != ms.MaxEntries:
return fmt.Errorf("expected max entries %v, got %v", ms.MaxEntries, m.maxEntries)
case m.flags != ms.Flags:
return fmt.Errorf("expected flags %v, got %v", ms.Flags, m.flags)
}
return nil
}
// Map represents a Map file descriptor.
//
// It is not safe to close a map which is used by other goroutines.
//
// Methods which take interface{} arguments by default encode
// them using binary.Read/Write in the machine's native endianness.
//
// Implement encoding.BinaryMarshaler or encoding.BinaryUnmarshaler
// if you require custom encoding.
type Map struct {
name string
fd *internal.FD
typ MapType
keySize uint32
valueSize uint32
maxEntries uint32
flags uint32
pinnedPath string
// Per CPU maps return values larger than the size in the spec
fullValueSize int
}
// NewMapFromFD creates a map from a raw fd.
//
// You should not use fd after calling this function.
func NewMapFromFD(fd int) (*Map, error) {
if fd < 0 {
return nil, errors.New("invalid fd")
}
return newMapFromFD(internal.NewFD(uint32(fd)))
}
func newMapFromFD(fd *internal.FD) (*Map, error) {
info, err := newMapInfoFromFd(fd)
if err != nil {
fd.Close()
return nil, fmt.Errorf("get map info: %s", err)
}
return newMap(fd, info.Name, info.Type, info.KeySize, info.ValueSize, info.MaxEntries, info.Flags)
}
// NewMap creates a new Map.
//
// It's equivalent to calling NewMapWithOptions with default options.
func NewMap(spec *MapSpec) (*Map, error) {
return NewMapWithOptions(spec, MapOptions{})
}
// NewMapWithOptions creates a new Map.
//
// Creating a map for the first time will perform feature detection
// by creating small, temporary maps.
//
// The caller is responsible for ensuring the process' rlimit is set
// sufficiently high for locking memory during map creation. This can be done
// by calling unix.Setrlimit with unix.RLIMIT_MEMLOCK prior to calling NewMapWithOptions.
func NewMapWithOptions(spec *MapSpec, opts MapOptions) (*Map, error) {
btfs := make(btfHandleCache)
defer btfs.close()
return newMapWithOptions(spec, opts, btfs)
}
func newMapWithOptions(spec *MapSpec, opts MapOptions, btfs btfHandleCache) (*Map, error) {
switch spec.Pinning {
case PinByName:
if spec.Name == "" || opts.PinPath == "" {
return nil, fmt.Errorf("pin by name: missing Name or PinPath")
}
m, err := LoadPinnedMap(filepath.Join(opts.PinPath, spec.Name))
if errors.Is(err, unix.ENOENT) {
break
}
if err != nil {
return nil, fmt.Errorf("load pinned map: %s", err)
}
if err := spec.checkCompatibility(m); err != nil {
m.Close()
return nil, fmt.Errorf("use pinned map %s: %s", spec.Name, err)
}
return m, nil
case PinNone:
// Nothing to do here
default:
return nil, fmt.Errorf("unsupported pin type %d", int(spec.Pinning))
}
var innerFd *internal.FD
if spec.Type == ArrayOfMaps || spec.Type == HashOfMaps {
if spec.InnerMap == nil {
return nil, fmt.Errorf("%s requires InnerMap", spec.Type)
}
if spec.InnerMap.Pinning != PinNone {
return nil, errors.New("inner maps cannot be pinned")
}
template, err := createMap(spec.InnerMap, nil, opts, btfs)
if err != nil {
return nil, err
}
defer template.Close()
innerFd = template.fd
}
m, err := createMap(spec, innerFd, opts, btfs)
if err != nil {
return nil, err
}
if spec.Pinning == PinByName {
if err := m.Pin(filepath.Join(opts.PinPath, spec.Name)); err != nil {
m.Close()
return nil, fmt.Errorf("pin map: %s", err)
}
}
return m, nil
}
func createMap(spec *MapSpec, inner *internal.FD, opts MapOptions, btfs btfHandleCache) (_ *Map, err error) {
closeOnError := func(closer io.Closer) {
if err != nil {
closer.Close()
}
}
spec = spec.Copy()
switch spec.Type {
case ArrayOfMaps:
fallthrough
case HashOfMaps:
if err := haveNestedMaps(); err != nil {
return nil, err
}
if spec.ValueSize != 0 && spec.ValueSize != 4 {
return nil, errors.New("ValueSize must be zero or four for map of map")
}
spec.ValueSize = 4
case PerfEventArray:
if spec.KeySize != 0 && spec.KeySize != 4 {
return nil, errors.New("KeySize must be zero or four for perf event array")
}
spec.KeySize = 4
if spec.ValueSize != 0 && spec.ValueSize != 4 {
return nil, errors.New("ValueSize must be zero or four for perf event array")
}
spec.ValueSize = 4
if spec.MaxEntries == 0 {
n, err := internal.PossibleCPUs()
if err != nil {
return nil, fmt.Errorf("perf event array: %w", err)
}
spec.MaxEntries = uint32(n)
}
}
if spec.Flags&(unix.BPF_F_RDONLY_PROG|unix.BPF_F_WRONLY_PROG) > 0 || spec.Freeze {
if err := haveMapMutabilityModifiers(); err != nil {
return nil, fmt.Errorf("map create: %w", err)
}
}
attr := bpfMapCreateAttr{
mapType: spec.Type,
keySize: spec.KeySize,
valueSize: spec.ValueSize,
maxEntries: spec.MaxEntries,
flags: spec.Flags,
numaNode: spec.NumaNode,
}
if inner != nil {
var err error
attr.innerMapFd, err = inner.Value()
if err != nil {
return nil, fmt.Errorf("map create: %w", err)
}
}
if haveObjName() == nil {
attr.mapName = newBPFObjName(spec.Name)
}
var btfDisabled bool
if spec.BTF != nil {
handle, err := btfs.load(btf.MapSpec(spec.BTF))
btfDisabled = errors.Is(err, btf.ErrNotSupported)
if err != nil && !btfDisabled {
return nil, fmt.Errorf("load BTF: %w", err)
}
if handle != nil {
attr.btfFd = uint32(handle.FD())
attr.btfKeyTypeID = btf.MapKey(spec.BTF).ID()
attr.btfValueTypeID = btf.MapValue(spec.BTF).ID()
}
}
fd, err := bpfMapCreate(&attr)
if err != nil {
if errors.Is(err, unix.EPERM) {
return nil, fmt.Errorf("map create: RLIMIT_MEMLOCK may be too low: %w", err)
}
if btfDisabled {
return nil, fmt.Errorf("map create without BTF: %w", err)
}
return nil, fmt.Errorf("map create: %w", err)
}
defer closeOnError(fd)
m, err := newMap(fd, spec.Name, spec.Type, spec.KeySize, spec.ValueSize, spec.MaxEntries, spec.Flags)
if err != nil {
return nil, fmt.Errorf("map create: %w", err)
}
if err := m.populate(spec.Contents); err != nil {
return nil, fmt.Errorf("map create: can't set initial contents: %w", err)
}
if spec.Freeze {
if err := m.Freeze(); err != nil {
return nil, fmt.Errorf("can't freeze map: %w", err)
}
}
return m, nil
}
func newMap(fd *internal.FD, name string, typ MapType, keySize, valueSize, maxEntries, flags uint32) (*Map, error) {
m := &Map{
name,
fd,
typ,
keySize,
valueSize,
maxEntries,
flags,
"",
int(valueSize),
}
if !typ.hasPerCPUValue() {
return m, nil
}
possibleCPUs, err := internal.PossibleCPUs()
if err != nil {
return nil, err
}
m.fullValueSize = align(int(valueSize), 8) * possibleCPUs
return m, nil
}
func (m *Map) String() string {
if m.name != "" {
return fmt.Sprintf("%s(%s)#%v", m.typ, m.name, m.fd)
}
return fmt.Sprintf("%s#%v", m.typ, m.fd)
}
// Type returns the underlying type of the map.
func (m *Map) Type() MapType {
return m.typ
}
// KeySize returns the size of the map key in bytes.
func (m *Map) KeySize() uint32 {
return m.keySize
}
// ValueSize returns the size of the map value in bytes.
func (m *Map) ValueSize() uint32 {
return m.valueSize
}
// MaxEntries returns the maximum number of elements the map can hold.
func (m *Map) MaxEntries() uint32 {
return m.maxEntries
}
// Flags returns the flags of the map.
func (m *Map) Flags() uint32 {
return m.flags
}
// Info returns metadata about the map.
func (m *Map) Info() (*MapInfo, error) {
return newMapInfoFromFd(m.fd)
}
// Lookup retrieves a value from a Map.
//
// Calls Close() on valueOut if it is of type **Map or **Program,
// and *valueOut is not nil.
//
// Returns an error if the key doesn't exist, see ErrKeyNotExist.
func (m *Map) Lookup(key, valueOut interface{}) error {
valuePtr, valueBytes := makeBuffer(valueOut, m.fullValueSize)
if err := m.lookup(key, valuePtr); err != nil {
return err
}
return m.unmarshalValue(valueOut, valueBytes)
}
// LookupAndDelete retrieves and deletes a value from a Map.
//
// Returns ErrKeyNotExist if the key doesn't exist.
func (m *Map) LookupAndDelete(key, valueOut interface{}) error {
valuePtr, valueBytes := makeBuffer(valueOut, m.fullValueSize)
keyPtr, err := m.marshalKey(key)
if err != nil {
return fmt.Errorf("can't marshal key: %w", err)
}
if err := bpfMapLookupAndDelete(m.fd, keyPtr, valuePtr); err != nil {
return fmt.Errorf("lookup and delete failed: %w", err)
}
return m.unmarshalValue(valueOut, valueBytes)
}
// LookupBytes gets a value from Map.
//
// Returns a nil value if a key doesn't exist.
func (m *Map) LookupBytes(key interface{}) ([]byte, error) {
valueBytes := make([]byte, m.fullValueSize)
valuePtr := internal.NewSlicePointer(valueBytes)
err := m.lookup(key, valuePtr)
if errors.Is(err, ErrKeyNotExist) {
return nil, nil
}
return valueBytes, err
}
func (m *Map) lookup(key interface{}, valueOut internal.Pointer) error {
keyPtr, err := m.marshalKey(key)
if err != nil {
return fmt.Errorf("can't marshal key: %w", err)
}
if err = bpfMapLookupElem(m.fd, keyPtr, valueOut); err != nil {
return fmt.Errorf("lookup failed: %w", err)
}
return nil
}
// MapUpdateFlags controls the behaviour of the Map.Update call.
//
// The exact semantics depend on the specific MapType.
type MapUpdateFlags uint64
const (
// UpdateAny creates a new element or update an existing one.
UpdateAny MapUpdateFlags = iota
// UpdateNoExist creates a new element.
UpdateNoExist MapUpdateFlags = 1 << (iota - 1)
// UpdateExist updates an existing element.
UpdateExist
)
// Put replaces or creates a value in map.
//
// It is equivalent to calling Update with UpdateAny.
func (m *Map) Put(key, value interface{}) error {
return m.Update(key, value, UpdateAny)
}
// Update changes the value of a key.
func (m *Map) Update(key, value interface{}, flags MapUpdateFlags) error {
keyPtr, err := m.marshalKey(key)
if err != nil {
return fmt.Errorf("can't marshal key: %w", err)
}
valuePtr, err := m.marshalValue(value)
if err != nil {
return fmt.Errorf("can't marshal value: %w", err)
}
if err = bpfMapUpdateElem(m.fd, keyPtr, valuePtr, uint64(flags)); err != nil {
return fmt.Errorf("update failed: %w", err)
}
return nil
}
// Delete removes a value.
//
// Returns ErrKeyNotExist if the key does not exist.
func (m *Map) Delete(key interface{}) error {
keyPtr, err := m.marshalKey(key)
if err != nil {
return fmt.Errorf("can't marshal key: %w", err)
}
if err = bpfMapDeleteElem(m.fd, keyPtr); err != nil {
return fmt.Errorf("delete failed: %w", err)
}
return nil
}
// NextKey finds the key following an initial key.
//
// See NextKeyBytes for details.
//
// Returns ErrKeyNotExist if there is no next key.
func (m *Map) NextKey(key, nextKeyOut interface{}) error {
nextKeyPtr, nextKeyBytes := makeBuffer(nextKeyOut, int(m.keySize))
if err := m.nextKey(key, nextKeyPtr); err != nil {
return err
}
if err := m.unmarshalKey(nextKeyOut, nextKeyBytes); err != nil {
return fmt.Errorf("can't unmarshal next key: %w", err)
}
return nil
}
// NextKeyBytes returns the key following an initial key as a byte slice.
//
// Passing nil will return the first key.
//
// Use Iterate if you want to traverse all entries in the map.
//
// Returns nil if there are no more keys.
func (m *Map) NextKeyBytes(key interface{}) ([]byte, error) {
nextKey := make([]byte, m.keySize)
nextKeyPtr := internal.NewSlicePointer(nextKey)
err := m.nextKey(key, nextKeyPtr)
if errors.Is(err, ErrKeyNotExist) {
return nil, nil
}
return nextKey, err
}
func (m *Map) nextKey(key interface{}, nextKeyOut internal.Pointer) error {
var (
keyPtr internal.Pointer
err error
)
if key != nil {
keyPtr, err = m.marshalKey(key)
if err != nil {
return fmt.Errorf("can't marshal key: %w", err)
}
}
if err = bpfMapGetNextKey(m.fd, keyPtr, nextKeyOut); err != nil {
return fmt.Errorf("next key failed: %w", err)
}
return nil
}
// BatchLookup looks up many elements in a map at once.
//
// "keysOut" and "valuesOut" must be of type slice, a pointer
// to a slice or buffer will not work.
// "prevKey" is the key to start the batch lookup from, it will
// *not* be included in the results. Use nil to start at the first key.
//
// ErrKeyNotExist is returned when the batch lookup has reached
// the end of all possible results, even when partial results
// are returned. It should be used to evaluate when lookup is "done".
func (m *Map) BatchLookup(prevKey, nextKeyOut, keysOut, valuesOut interface{}, opts *BatchOptions) (int, error) {
return m.batchLookup(internal.BPF_MAP_LOOKUP_BATCH, prevKey, nextKeyOut, keysOut, valuesOut, opts)
}
// BatchLookupAndDelete looks up many elements in a map at once,
//
// It then deletes all those elements.
// "keysOut" and "valuesOut" must be of type slice, a pointer
// to a slice or buffer will not work.
// "prevKey" is the key to start the batch lookup from, it will
// *not* be included in the results. Use nil to start at the first key.
//
// ErrKeyNotExist is returned when the batch lookup has reached
// the end of all possible results, even when partial results
// are returned. It should be used to evaluate when lookup is "done".
func (m *Map) BatchLookupAndDelete(prevKey, nextKeyOut, keysOut, valuesOut interface{}, opts *BatchOptions) (int, error) {
return m.batchLookup(internal.BPF_MAP_LOOKUP_AND_DELETE_BATCH, prevKey, nextKeyOut, keysOut, valuesOut, opts)
}
func (m *Map) batchLookup(cmd internal.BPFCmd, startKey, nextKeyOut, keysOut, valuesOut interface{}, opts *BatchOptions) (int, error) {
if err := haveBatchAPI(); err != nil {
return 0, err
}
if m.typ.hasPerCPUValue() {
return 0, ErrNotSupported
}
keysValue := reflect.ValueOf(keysOut)
if keysValue.Kind() != reflect.Slice {
return 0, fmt.Errorf("keys must be a slice")
}
valuesValue := reflect.ValueOf(valuesOut)
if valuesValue.Kind() != reflect.Slice {
return 0, fmt.Errorf("valuesOut must be a slice")
}
count := keysValue.Len()
if count != valuesValue.Len() {
return 0, fmt.Errorf("keysOut and valuesOut must be the same length")
}
keyBuf := make([]byte, count*int(m.keySize))
keyPtr := internal.NewSlicePointer(keyBuf)
valueBuf := make([]byte, count*int(m.fullValueSize))
valuePtr := internal.NewSlicePointer(valueBuf)
var (
startPtr internal.Pointer
err error
retErr error
)
if startKey != nil {
startPtr, err = marshalPtr(startKey, int(m.keySize))
if err != nil {
return 0, err
}
}
nextPtr, nextBuf := makeBuffer(nextKeyOut, int(m.keySize))
ct, err := bpfMapBatch(cmd, m.fd, startPtr, nextPtr, keyPtr, valuePtr, uint32(count), opts)
if err != nil {
if !errors.Is(err, ErrKeyNotExist) {
return 0, err
}
retErr = ErrKeyNotExist
}
err = m.unmarshalKey(nextKeyOut, nextBuf)
if err != nil {
return 0, err
}
err = unmarshalBytes(keysOut, keyBuf)
if err != nil {
return 0, err
}
err = unmarshalBytes(valuesOut, valueBuf)
if err != nil {
retErr = err
}
return int(ct), retErr
}
// BatchUpdate updates the map with multiple keys and values
// simultaneously.
// "keys" and "values" must be of type slice, a pointer
// to a slice or buffer will not work.
func (m *Map) BatchUpdate(keys, values interface{}, opts *BatchOptions) (int, error) {
if err := haveBatchAPI(); err != nil {
return 0, err
}
if m.typ.hasPerCPUValue() {
return 0, ErrNotSupported
}
keysValue := reflect.ValueOf(keys)
if keysValue.Kind() != reflect.Slice {
return 0, fmt.Errorf("keys must be a slice")
}
valuesValue := reflect.ValueOf(values)
if valuesValue.Kind() != reflect.Slice {
return 0, fmt.Errorf("values must be a slice")
}
var (
count = keysValue.Len()
valuePtr internal.Pointer
err error
)
if count != valuesValue.Len() {
return 0, fmt.Errorf("keys and values must be the same length")
}
keyPtr, err := marshalPtr(keys, count*int(m.keySize))
if err != nil {
return 0, err
}
valuePtr, err = marshalPtr(values, count*int(m.valueSize))
if err != nil {
return 0, err
}
var nilPtr internal.Pointer
ct, err := bpfMapBatch(internal.BPF_MAP_UPDATE_BATCH, m.fd, nilPtr, nilPtr, keyPtr, valuePtr, uint32(count), opts)
return int(ct), err
}
// BatchDelete batch deletes entries in the map by keys.
// "keys" must be of type slice, a pointer to a slice or buffer will not work.
func (m *Map) BatchDelete(keys interface{}, opts *BatchOptions) (int, error) {
if err := haveBatchAPI(); err != nil {
return 0, err
}
if m.typ.hasPerCPUValue() {
return 0, ErrNotSupported
}
keysValue := reflect.ValueOf(keys)
if keysValue.Kind() != reflect.Slice {
return 0, fmt.Errorf("keys must be a slice")
}
count := keysValue.Len()
keyPtr, err := marshalPtr(keys, count*int(m.keySize))
if err != nil {
return 0, fmt.Errorf("cannot marshal keys: %v", err)
}
var nilPtr internal.Pointer
ct, err := bpfMapBatch(internal.BPF_MAP_DELETE_BATCH, m.fd, nilPtr, nilPtr, keyPtr, nilPtr, uint32(count), opts)
return int(ct), err
}
// Iterate traverses a map.
//
// It's safe to create multiple iterators at the same time.
//
// It's not possible to guarantee that all keys in a map will be
// returned if there are concurrent modifications to the map.
func (m *Map) Iterate() *MapIterator {
return newMapIterator(m)
}
// Close removes a Map
func (m *Map) Close() error {
if m == nil {
// This makes it easier to clean up when iterating maps
// of maps / programs.
return nil
}
return m.fd.Close()
}
// FD gets the file descriptor of the Map.
//
// Calling this function is invalid after Close has been called.
func (m *Map) FD() int {
fd, err := m.fd.Value()
if err != nil {
// Best effort: -1 is the number most likely to be an
// invalid file descriptor.
return -1
}
return int(fd)
}
// Clone creates a duplicate of the Map.
//
// Closing the duplicate does not affect the original, and vice versa.
// Changes made to the map are reflected by both instances however.
// If the original map was pinned, the cloned map will not be pinned by default.
//
// Cloning a nil Map returns nil.
func (m *Map) Clone() (*Map, error) {
if m == nil {
return nil, nil
}
dup, err := m.fd.Dup()
if err != nil {
return nil, fmt.Errorf("can't clone map: %w", err)
}
return &Map{
m.name,
dup,
m.typ,
m.keySize,
m.valueSize,
m.maxEntries,
m.flags,
"",
m.fullValueSize,
}, nil
}
// Pin persists the map on the BPF virtual file system past the lifetime of
// the process that created it .
//
// Calling Pin on a previously pinned map will override the path.
// You can Clone a map to pin it to a different path.
//
// This requires bpffs to be mounted above fileName. See https://docs.cilium.io/en/k8s-doc/admin/#admin-mount-bpffs
func (m *Map) Pin(fileName string) error {
if err := pin(m.pinnedPath, fileName, m.fd); err != nil {
return err
}
m.pinnedPath = fileName
return nil
}
// Unpin removes the persisted state for the map from the BPF virtual filesystem.
//
// Failed calls to Unpin will not alter the state returned by IsPinned.
//
// Unpinning an unpinned Map returns nil.
func (m *Map) Unpin() error {
if err := unpin(m.pinnedPath); err != nil {
return err
}
m.pinnedPath = ""
return nil
}
// IsPinned returns true if the map has a non-empty pinned path.
func (m *Map) IsPinned() bool {
if m.pinnedPath == "" {
return false
}
return true
}
// Freeze prevents a map to be modified from user space.
//
// It makes no changes to kernel-side restrictions.
func (m *Map) Freeze() error {
if err := haveMapMutabilityModifiers(); err != nil {
return fmt.Errorf("can't freeze map: %w", err)
}
if err := bpfMapFreeze(m.fd); err != nil {
return fmt.Errorf("can't freeze map: %w", err)
}
return nil
}
func (m *Map) populate(contents []MapKV) error {
for _, kv := range contents {
if err := m.Put(kv.Key, kv.Value); err != nil {
return fmt.Errorf("key %v: %w", kv.Key, err)
}
}
return nil
}
func (m *Map) marshalKey(data interface{}) (internal.Pointer, error) {
if data == nil {
if m.keySize == 0 {
// Queues have a key length of zero, so passing nil here is valid.
return internal.NewPointer(nil), nil
}
return internal.Pointer{}, errors.New("can't use nil as key of map")
}
return marshalPtr(data, int(m.keySize))
}
func (m *Map) unmarshalKey(data interface{}, buf []byte) error {
if buf == nil {
// This is from a makeBuffer call, nothing do do here.
return nil
}
return unmarshalBytes(data, buf)
}
func (m *Map) marshalValue(data interface{}) (internal.Pointer, error) {
if m.typ.hasPerCPUValue() {
return marshalPerCPUValue(data, int(m.valueSize))
}
var (
buf []byte
err error
)
switch value := data.(type) {
case *Map:
if !m.typ.canStoreMap() {
return internal.Pointer{}, fmt.Errorf("can't store map in %s", m.typ)
}
buf, err = marshalMap(value, int(m.valueSize))
case *Program:
if !m.typ.canStoreProgram() {
return internal.Pointer{}, fmt.Errorf("can't store program in %s", m.typ)
}
buf, err = marshalProgram(value, int(m.valueSize))
default:
return marshalPtr(data, int(m.valueSize))
}
if err != nil {
return internal.Pointer{}, err
}
return internal.NewSlicePointer(buf), nil
}
func (m *Map) unmarshalValue(value interface{}, buf []byte) error {
if buf == nil {
// This is from a makeBuffer call, nothing do do here.
return nil
}
if m.typ.hasPerCPUValue() {
return unmarshalPerCPUValue(value, int(m.valueSize), buf)
}
switch value := value.(type) {
case **Map:
if !m.typ.canStoreMap() {
return fmt.Errorf("can't read a map from %s", m.typ)
}
other, err := unmarshalMap(buf)
if err != nil {
return err
}
(*value).Close()
*value = other
return nil
case *Map:
if !m.typ.canStoreMap() {
return fmt.Errorf("can't read a map from %s", m.typ)
}
return errors.New("require pointer to *Map")
case **Program:
if !m.typ.canStoreProgram() {
return fmt.Errorf("can't read a program from %s", m.typ)
}
other, err := unmarshalProgram(buf)
if err != nil {
return err
}
(*value).Close()
*value = other
return nil
case *Program:
if !m.typ.canStoreProgram() {
return fmt.Errorf("can't read a program from %s", m.typ)
}
return errors.New("require pointer to *Program")
}
return unmarshalBytes(value, buf)
}
// LoadPinnedMap load a Map from a BPF file.
func LoadPinnedMap(fileName string) (*Map, error) {
fd, err := internal.BPFObjGet(fileName)
if err != nil {
return nil, err
}
m, err := newMapFromFD(fd)
if err == nil {
m.pinnedPath = fileName
}
return m, err
}
// unmarshalMap creates a map from a map ID encoded in host endianness.
func unmarshalMap(buf []byte) (*Map, error) {
if len(buf) != 4 {
return nil, errors.New("map id requires 4 byte value")
}
id := internal.NativeEndian.Uint32(buf)
return NewMapFromID(MapID(id))
}
// marshalMap marshals the fd of a map into a buffer in host endianness.
func marshalMap(m *Map, length int) ([]byte, error) {
if length != 4 {
return nil, fmt.Errorf("can't marshal map to %d bytes", length)
}
fd, err := m.fd.Value()
if err != nil {
return nil, err
}
buf := make([]byte, 4)
internal.NativeEndian.PutUint32(buf, fd)
return buf, nil
}
func patchValue(value []byte, typ btf.Type, replacements map[string]interface{}) error {
replaced := make(map[string]bool)
replace := func(name string, offset, size int, replacement interface{}) error {
if offset+size > len(value) {
return fmt.Errorf("%s: offset %d(+%d) is out of bounds", name, offset, size)
}
buf, err := marshalBytes(replacement, size)
if err != nil {
return fmt.Errorf("marshal %s: %w", name, err)
}
copy(value[offset:offset+size], buf)
replaced[name] = true
return nil
}
switch parent := typ.(type) {
case *btf.Datasec:
for _, secinfo := range parent.Vars {
name := string(secinfo.Type.(*btf.Var).Name)
replacement, ok := replacements[name]
if !ok {
continue
}
err := replace(name, int(secinfo.Offset), int(secinfo.Size), replacement)
if err != nil {
return err
}
}
default:
return fmt.Errorf("patching %T is not supported", typ)
}
if len(replaced) == len(replacements) {
return nil
}
var missing []string
for name := range replacements {
if !replaced[name] {
missing = append(missing, name)
}
}
if len(missing) == 1 {
return fmt.Errorf("unknown field: %s", missing[0])
}
return fmt.Errorf("unknown fields: %s", strings.Join(missing, ","))
}
// MapIterator iterates a Map.
//
// See Map.Iterate.
type MapIterator struct {
target *Map
prevKey interface{}
prevBytes []byte
count, maxEntries uint32
done bool
err error
}
func newMapIterator(target *Map) *MapIterator {
return &MapIterator{
target: target,
maxEntries: target.maxEntries,
prevBytes: make([]byte, target.keySize),
}
}
// Next decodes the next key and value.
//
// Iterating a hash map from which keys are being deleted is not
// safe. You may see the same key multiple times. Iteration may
// also abort with an error, see IsIterationAborted.
//
// Returns false if there are no more entries. You must check
// the result of Err afterwards.
//
// See Map.Get for further caveats around valueOut.
func (mi *MapIterator) Next(keyOut, valueOut interface{}) bool {
if mi.err != nil || mi.done {
return false
}
// For array-like maps NextKeyBytes returns nil only on after maxEntries
// iterations.
for mi.count <= mi.maxEntries {
var nextBytes []byte
nextBytes, mi.err = mi.target.NextKeyBytes(mi.prevKey)
if mi.err != nil {
return false
}
if nextBytes == nil {
mi.done = true
return false
}
// The user can get access to nextBytes since unmarshalBytes
// does not copy when unmarshaling into a []byte.
// Make a copy to prevent accidental corruption of
// iterator state.
copy(mi.prevBytes, nextBytes)
mi.prevKey = mi.prevBytes
mi.count++
mi.err = mi.target.Lookup(nextBytes, valueOut)
if errors.Is(mi.err, ErrKeyNotExist) {
// Even though the key should be valid, we couldn't look up
// its value. If we're iterating a hash map this is probably
// because a concurrent delete removed the value before we
// could get it. This means that the next call to NextKeyBytes
// is very likely to restart iteration.
// If we're iterating one of the fd maps like
// ProgramArray it means that a given slot doesn't have
// a valid fd associated. It's OK to continue to the next slot.
continue
}
if mi.err != nil {
return false
}
mi.err = mi.target.unmarshalKey(keyOut, nextBytes)
return mi.err == nil
}
mi.err = fmt.Errorf("%w", ErrIterationAborted)
return false
}
// Err returns any encountered error.
//
// The method must be called after Next returns nil.
//
// Returns ErrIterationAborted if it wasn't possible to do a full iteration.
func (mi *MapIterator) Err() error {
return mi.err
}
// MapGetNextID returns the ID of the next eBPF map.
//
// Returns ErrNotExist, if there is no next eBPF map.
func MapGetNextID(startID MapID) (MapID, error) {
id, err := objGetNextID(internal.BPF_MAP_GET_NEXT_ID, uint32(startID))
return MapID(id), err
}
// NewMapFromID returns the map for a given id.
//
// Returns ErrNotExist, if there is no eBPF map with the given id.
func NewMapFromID(id MapID) (*Map, error) {
fd, err := bpfObjGetFDByID(internal.BPF_MAP_GET_FD_BY_ID, uint32(id))
if err != nil {
return nil, err
}
return newMapFromFD(fd)
}
// ID returns the systemwide unique ID of the map.
//
// Deprecated: use MapInfo.ID() instead.
func (m *Map) ID() (MapID, error) {
info, err := bpfGetMapInfoByFD(m.fd)
if err != nil {
return MapID(0), err
}
return MapID(info.id), nil
}