diff options
author | 2023-04-03 11:16:17 +0200 | |
---|---|---|
committer | 2023-04-03 11:16:17 +0200 | |
commit | 57dc742c76d7876a2457594715a7b5bc2c9a92bd (patch) | |
tree | 76be1ec744face5bf4f617d4c9fca084707e4268 /vendor/github.com/cilium/ebpf/btf | |
parent | [bugfix/frontend] Preload css styles (#1638) (diff) | |
download | gotosocial-57dc742c76d7876a2457594715a7b5bc2c9a92bd.tar.xz |
[chore]: Bump github.com/KimMachineGun/automemlimit from 0.2.4 to 0.2.5 (#1666)
Bumps [github.com/KimMachineGun/automemlimit](https://github.com/KimMachineGun/automemlimit) from 0.2.4 to 0.2.5.
- [Release notes](https://github.com/KimMachineGun/automemlimit/releases)
- [Commits](https://github.com/KimMachineGun/automemlimit/compare/v0.2.4...v0.2.5)
---
updated-dependencies:
- dependency-name: github.com/KimMachineGun/automemlimit
dependency-type: direct:production
update-type: version-update:semver-patch
...
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Diffstat (limited to 'vendor/github.com/cilium/ebpf/btf')
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/btf.go | 897 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/btf_types.go | 343 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/btf_types_string.go | 44 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/core.go | 972 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/doc.go | 5 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/ext_info.go | 721 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/format.go | 319 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/handle.go | 121 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/strings.go | 128 | ||||
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/types.go | 1212 |
10 files changed, 4762 insertions, 0 deletions
diff --git a/vendor/github.com/cilium/ebpf/btf/btf.go b/vendor/github.com/cilium/ebpf/btf/btf.go new file mode 100644 index 000000000..a5969332a --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/btf.go @@ -0,0 +1,897 @@ +package btf + +import ( + "bufio" + "bytes" + "debug/elf" + "encoding/binary" + "errors" + "fmt" + "io" + "math" + "os" + "reflect" + + "github.com/cilium/ebpf/internal" + "github.com/cilium/ebpf/internal/sys" + "github.com/cilium/ebpf/internal/unix" +) + +const btfMagic = 0xeB9F + +// Errors returned by BTF functions. +var ( + ErrNotSupported = internal.ErrNotSupported + ErrNotFound = errors.New("not found") + ErrNoExtendedInfo = errors.New("no extended info") +) + +// ID represents the unique ID of a BTF object. +type ID = sys.BTFID + +// Spec represents decoded BTF. +type Spec struct { + // Data from .BTF. + rawTypes []rawType + strings *stringTable + + // All types contained by the spec. For the base type, the position of + // a type in the slice is its ID. + types types + + // Type IDs indexed by type. + typeIDs map[Type]TypeID + + // Types indexed by essential name. + // Includes all struct flavors and types with the same name. + namedTypes map[essentialName][]Type + + byteOrder binary.ByteOrder +} + +type btfHeader struct { + Magic uint16 + Version uint8 + Flags uint8 + HdrLen uint32 + + TypeOff uint32 + TypeLen uint32 + StringOff uint32 + StringLen uint32 +} + +// typeStart returns the offset from the beginning of the .BTF section +// to the start of its type entries. +func (h *btfHeader) typeStart() int64 { + return int64(h.HdrLen + h.TypeOff) +} + +// stringStart returns the offset from the beginning of the .BTF section +// to the start of its string table. +func (h *btfHeader) stringStart() int64 { + return int64(h.HdrLen + h.StringOff) +} + +// LoadSpec opens file and calls LoadSpecFromReader on it. +func LoadSpec(file string) (*Spec, error) { + fh, err := os.Open(file) + if err != nil { + return nil, err + } + defer fh.Close() + + return LoadSpecFromReader(fh) +} + +// LoadSpecFromReader reads from an ELF or a raw BTF blob. +// +// Returns ErrNotFound if reading from an ELF which contains no BTF. ExtInfos +// may be nil. +func LoadSpecFromReader(rd io.ReaderAt) (*Spec, error) { + file, err := internal.NewSafeELFFile(rd) + if err != nil { + if bo := guessRawBTFByteOrder(rd); bo != nil { + // Try to parse a naked BTF blob. This will return an error if + // we encounter a Datasec, since we can't fix it up. + spec, err := loadRawSpec(io.NewSectionReader(rd, 0, math.MaxInt64), bo, nil, nil) + return spec, err + } + + return nil, err + } + + return loadSpecFromELF(file) +} + +// LoadSpecAndExtInfosFromReader reads from an ELF. +// +// ExtInfos may be nil if the ELF doesn't contain section metadta. +// Returns ErrNotFound if the ELF contains no BTF. +func LoadSpecAndExtInfosFromReader(rd io.ReaderAt) (*Spec, *ExtInfos, error) { + file, err := internal.NewSafeELFFile(rd) + if err != nil { + return nil, nil, err + } + + spec, err := loadSpecFromELF(file) + if err != nil { + return nil, nil, err + } + + extInfos, err := loadExtInfosFromELF(file, spec.types, spec.strings) + if err != nil && !errors.Is(err, ErrNotFound) { + return nil, nil, err + } + + return spec, extInfos, nil +} + +// variableOffsets extracts all symbols offsets from an ELF and indexes them by +// section and variable name. +// +// References to variables in BTF data sections carry unsigned 32-bit offsets. +// Some ELF symbols (e.g. in vmlinux) may point to virtual memory that is well +// beyond this range. Since these symbols cannot be described by BTF info, +// ignore them here. +func variableOffsets(file *internal.SafeELFFile) (map[variable]uint32, error) { + symbols, err := file.Symbols() + if err != nil { + return nil, fmt.Errorf("can't read symbols: %v", err) + } + + variableOffsets := make(map[variable]uint32) + for _, symbol := range symbols { + if idx := symbol.Section; idx >= elf.SHN_LORESERVE && idx <= elf.SHN_HIRESERVE { + // Ignore things like SHN_ABS + continue + } + + if symbol.Value > math.MaxUint32 { + // VarSecinfo offset is u32, cannot reference symbols in higher regions. + continue + } + + if int(symbol.Section) >= len(file.Sections) { + return nil, fmt.Errorf("symbol %s: invalid section %d", symbol.Name, symbol.Section) + } + + secName := file.Sections[symbol.Section].Name + variableOffsets[variable{secName, symbol.Name}] = uint32(symbol.Value) + } + + return variableOffsets, nil +} + +func loadSpecFromELF(file *internal.SafeELFFile) (*Spec, error) { + var ( + btfSection *elf.Section + sectionSizes = make(map[string]uint32) + ) + + for _, sec := range file.Sections { + switch sec.Name { + case ".BTF": + btfSection = sec + default: + if sec.Type != elf.SHT_PROGBITS && sec.Type != elf.SHT_NOBITS { + break + } + + if sec.Size > math.MaxUint32 { + return nil, fmt.Errorf("section %s exceeds maximum size", sec.Name) + } + + sectionSizes[sec.Name] = uint32(sec.Size) + } + } + + if btfSection == nil { + return nil, fmt.Errorf("btf: %w", ErrNotFound) + } + + vars, err := variableOffsets(file) + if err != nil { + return nil, err + } + + if btfSection.ReaderAt == nil { + return nil, fmt.Errorf("compressed BTF is not supported") + } + + rawTypes, rawStrings, err := parseBTF(btfSection.ReaderAt, file.ByteOrder, nil) + if err != nil { + return nil, err + } + + err = fixupDatasec(rawTypes, rawStrings, sectionSizes, vars) + if err != nil { + return nil, err + } + + return inflateSpec(rawTypes, rawStrings, file.ByteOrder, nil) +} + +func loadRawSpec(btf io.ReaderAt, bo binary.ByteOrder, + baseTypes types, baseStrings *stringTable) (*Spec, error) { + + rawTypes, rawStrings, err := parseBTF(btf, bo, baseStrings) + if err != nil { + return nil, err + } + + return inflateSpec(rawTypes, rawStrings, bo, baseTypes) +} + +func inflateSpec(rawTypes []rawType, rawStrings *stringTable, bo binary.ByteOrder, + baseTypes types) (*Spec, error) { + + types, err := inflateRawTypes(rawTypes, baseTypes, rawStrings) + if err != nil { + return nil, err + } + + typeIDs, typesByName := indexTypes(types, TypeID(len(baseTypes))) + + return &Spec{ + rawTypes: rawTypes, + namedTypes: typesByName, + typeIDs: typeIDs, + types: types, + strings: rawStrings, + byteOrder: bo, + }, nil +} + +func indexTypes(types []Type, typeIDOffset TypeID) (map[Type]TypeID, map[essentialName][]Type) { + namedTypes := 0 + for _, typ := range types { + if typ.TypeName() != "" { + // Do a pre-pass to figure out how big types by name has to be. + // Most types have unique names, so it's OK to ignore essentialName + // here. + namedTypes++ + } + } + + typeIDs := make(map[Type]TypeID, len(types)) + typesByName := make(map[essentialName][]Type, namedTypes) + + for i, typ := range types { + if name := newEssentialName(typ.TypeName()); name != "" { + typesByName[name] = append(typesByName[name], typ) + } + typeIDs[typ] = TypeID(i) + typeIDOffset + } + + return typeIDs, typesByName +} + +// LoadKernelSpec returns the current kernel's BTF information. +// +// Defaults to /sys/kernel/btf/vmlinux and falls back to scanning the file system +// for vmlinux ELFs. Returns an error wrapping ErrNotSupported if BTF is not enabled. +func LoadKernelSpec() (*Spec, error) { + fh, err := os.Open("/sys/kernel/btf/vmlinux") + if err == nil { + defer fh.Close() + + return loadRawSpec(fh, internal.NativeEndian, nil, nil) + } + + file, err := findVMLinux() + if err != nil { + return nil, err + } + defer file.Close() + + return loadSpecFromELF(file) +} + +// findVMLinux scans multiple well-known paths for vmlinux kernel images. +func findVMLinux() (*internal.SafeELFFile, error) { + release, err := internal.KernelRelease() + if err != nil { + return nil, err + } + + // use same list of locations as libbpf + // https://github.com/libbpf/libbpf/blob/9a3a42608dbe3731256a5682a125ac1e23bced8f/src/btf.c#L3114-L3122 + locations := []string{ + "/boot/vmlinux-%s", + "/lib/modules/%s/vmlinux-%[1]s", + "/lib/modules/%s/build/vmlinux", + "/usr/lib/modules/%s/kernel/vmlinux", + "/usr/lib/debug/boot/vmlinux-%s", + "/usr/lib/debug/boot/vmlinux-%s.debug", + "/usr/lib/debug/lib/modules/%s/vmlinux", + } + + for _, loc := range locations { + file, err := internal.OpenSafeELFFile(fmt.Sprintf(loc, release)) + if errors.Is(err, os.ErrNotExist) { + continue + } + return file, err + } + + return nil, fmt.Errorf("no BTF found for kernel version %s: %w", release, internal.ErrNotSupported) +} + +// parseBTFHeader parses the header of the .BTF section. +func parseBTFHeader(r io.Reader, bo binary.ByteOrder) (*btfHeader, error) { + var header btfHeader + if err := binary.Read(r, bo, &header); err != nil { + return nil, fmt.Errorf("can't read header: %v", err) + } + + if header.Magic != btfMagic { + return nil, fmt.Errorf("incorrect magic value %v", header.Magic) + } + + if header.Version != 1 { + return nil, fmt.Errorf("unexpected version %v", header.Version) + } + + if header.Flags != 0 { + return nil, fmt.Errorf("unsupported flags %v", header.Flags) + } + + remainder := int64(header.HdrLen) - int64(binary.Size(&header)) + if remainder < 0 { + return nil, errors.New("header length shorter than btfHeader size") + } + + if _, err := io.CopyN(internal.DiscardZeroes{}, r, remainder); err != nil { + return nil, fmt.Errorf("header padding: %v", err) + } + + return &header, nil +} + +func guessRawBTFByteOrder(r io.ReaderAt) binary.ByteOrder { + buf := new(bufio.Reader) + for _, bo := range []binary.ByteOrder{ + binary.LittleEndian, + binary.BigEndian, + } { + buf.Reset(io.NewSectionReader(r, 0, math.MaxInt64)) + if _, err := parseBTFHeader(buf, bo); err == nil { + return bo + } + } + + return nil +} + +// parseBTF reads a .BTF section into memory and parses it into a list of +// raw types and a string table. +func parseBTF(btf io.ReaderAt, bo binary.ByteOrder, baseStrings *stringTable) ([]rawType, *stringTable, error) { + buf := internal.NewBufferedSectionReader(btf, 0, math.MaxInt64) + header, err := parseBTFHeader(buf, bo) + if err != nil { + return nil, nil, fmt.Errorf("parsing .BTF header: %v", err) + } + + rawStrings, err := readStringTable(io.NewSectionReader(btf, header.stringStart(), int64(header.StringLen)), + baseStrings) + if err != nil { + return nil, nil, fmt.Errorf("can't read type names: %w", err) + } + + buf.Reset(io.NewSectionReader(btf, header.typeStart(), int64(header.TypeLen))) + rawTypes, err := readTypes(buf, bo, header.TypeLen) + if err != nil { + return nil, nil, fmt.Errorf("can't read types: %w", err) + } + + return rawTypes, rawStrings, nil +} + +type variable struct { + section string + name string +} + +func fixupDatasec(rawTypes []rawType, rawStrings *stringTable, sectionSizes map[string]uint32, variableOffsets map[variable]uint32) error { + for i, rawType := range rawTypes { + if rawType.Kind() != kindDatasec { + continue + } + + name, err := rawStrings.Lookup(rawType.NameOff) + if err != nil { + return err + } + + if name == ".kconfig" || name == ".ksyms" { + return fmt.Errorf("reference to %s: %w", name, ErrNotSupported) + } + + if rawTypes[i].SizeType != 0 { + continue + } + + size, ok := sectionSizes[name] + if !ok { + return fmt.Errorf("data section %s: missing size", name) + } + + rawTypes[i].SizeType = size + + secinfos := rawType.data.([]btfVarSecinfo) + for j, secInfo := range secinfos { + id := int(secInfo.Type - 1) + if id >= len(rawTypes) { + return fmt.Errorf("data section %s: invalid type id %d for variable %d", name, id, j) + } + + varName, err := rawStrings.Lookup(rawTypes[id].NameOff) + if err != nil { + return fmt.Errorf("data section %s: can't get name for type %d: %w", name, id, err) + } + + offset, ok := variableOffsets[variable{name, varName}] + if !ok { + return fmt.Errorf("data section %s: missing offset for variable %s", name, varName) + } + + secinfos[j].Offset = offset + } + } + + return nil +} + +// Copy creates a copy of Spec. +func (s *Spec) Copy() *Spec { + types := copyTypes(s.types, nil) + + typeIDOffset := TypeID(0) + if len(s.types) != 0 { + typeIDOffset = s.typeIDs[s.types[0]] + } + typeIDs, typesByName := indexTypes(types, typeIDOffset) + + // NB: Other parts of spec are not copied since they are immutable. + return &Spec{ + s.rawTypes, + s.strings, + types, + typeIDs, + typesByName, + s.byteOrder, + } +} + +type marshalOpts struct { + ByteOrder binary.ByteOrder + StripFuncLinkage bool +} + +func (s *Spec) marshal(opts marshalOpts) ([]byte, error) { + var ( + buf bytes.Buffer + header = new(btfHeader) + headerLen = binary.Size(header) + ) + + // Reserve space for the header. We have to write it last since + // we don't know the size of the type section yet. + _, _ = buf.Write(make([]byte, headerLen)) + + // Write type section, just after the header. + for _, raw := range s.rawTypes { + switch { + case opts.StripFuncLinkage && raw.Kind() == kindFunc: + raw.SetLinkage(StaticFunc) + } + + if err := raw.Marshal(&buf, opts.ByteOrder); err != nil { + return nil, fmt.Errorf("can't marshal BTF: %w", err) + } + } + + typeLen := uint32(buf.Len() - headerLen) + + // Write string section after type section. + stringsLen := s.strings.Length() + buf.Grow(stringsLen) + if err := s.strings.Marshal(&buf); err != nil { + return nil, err + } + + // Fill out the header, and write it out. + header = &btfHeader{ + Magic: btfMagic, + Version: 1, + Flags: 0, + HdrLen: uint32(headerLen), + TypeOff: 0, + TypeLen: typeLen, + StringOff: typeLen, + StringLen: uint32(stringsLen), + } + + raw := buf.Bytes() + err := binary.Write(sliceWriter(raw[:headerLen]), opts.ByteOrder, header) + if err != nil { + return nil, fmt.Errorf("can't write header: %v", err) + } + + return raw, nil +} + +type sliceWriter []byte + +func (sw sliceWriter) Write(p []byte) (int, error) { + if len(p) != len(sw) { + return 0, errors.New("size doesn't match") + } + + return copy(sw, p), nil +} + +// TypeByID returns the BTF Type with the given type ID. +// +// Returns an error wrapping ErrNotFound if a Type with the given ID +// does not exist in the Spec. +func (s *Spec) TypeByID(id TypeID) (Type, error) { + return s.types.ByID(id) +} + +// TypeID returns the ID for a given Type. +// +// Returns an error wrapping ErrNoFound if the type isn't part of the Spec. +func (s *Spec) TypeID(typ Type) (TypeID, error) { + if _, ok := typ.(*Void); ok { + // Equality is weird for void, since it is a zero sized type. + return 0, nil + } + + id, ok := s.typeIDs[typ] + if !ok { + return 0, fmt.Errorf("no ID for type %s: %w", typ, ErrNotFound) + } + + return id, nil +} + +// AnyTypesByName returns a list of BTF Types with the given name. +// +// If the BTF blob describes multiple compilation units like vmlinux, multiple +// Types with the same name and kind can exist, but might not describe the same +// data structure. +// +// Returns an error wrapping ErrNotFound if no matching Type exists in the Spec. +func (s *Spec) AnyTypesByName(name string) ([]Type, error) { + types := s.namedTypes[newEssentialName(name)] + if len(types) == 0 { + return nil, fmt.Errorf("type name %s: %w", name, ErrNotFound) + } + + // Return a copy to prevent changes to namedTypes. + result := make([]Type, 0, len(types)) + for _, t := range types { + // Match against the full name, not just the essential one + // in case the type being looked up is a struct flavor. + if t.TypeName() == name { + result = append(result, t) + } + } + return result, nil +} + +// AnyTypeByName returns a Type with the given name. +// +// Returns an error if multiple types of that name exist. +func (s *Spec) AnyTypeByName(name string) (Type, error) { + types, err := s.AnyTypesByName(name) + if err != nil { + return nil, err + } + + if len(types) > 1 { + return nil, fmt.Errorf("found multiple types: %v", types) + } + + return types[0], nil +} + +// TypeByName searches for a Type with a specific name. Since multiple +// Types with the same name can exist, the parameter typ is taken to +// narrow down the search in case of a clash. +// +// typ must be a non-nil pointer to an implementation of a Type. +// On success, the address of the found Type will be copied to typ. +// +// Returns an error wrapping ErrNotFound if no matching +// Type exists in the Spec. If multiple candidates are found, +// an error is returned. +func (s *Spec) TypeByName(name string, typ interface{}) error { + typValue := reflect.ValueOf(typ) + if typValue.Kind() != reflect.Ptr { + return fmt.Errorf("%T is not a pointer", typ) + } + + typPtr := typValue.Elem() + if !typPtr.CanSet() { + return fmt.Errorf("%T cannot be set", typ) + } + + wanted := typPtr.Type() + if !wanted.AssignableTo(reflect.TypeOf((*Type)(nil)).Elem()) { + return fmt.Errorf("%T does not satisfy Type interface", typ) + } + + types, err := s.AnyTypesByName(name) + if err != nil { + return err + } + + var candidate Type + for _, typ := range types { + if reflect.TypeOf(typ) != wanted { + continue + } + + if candidate != nil { + return fmt.Errorf("type %s: multiple candidates for %T", name, typ) + } + + candidate = typ + } + + if candidate == nil { + return fmt.Errorf("type %s: %w", name, ErrNotFound) + } + + typPtr.Set(reflect.ValueOf(candidate)) + + return nil +} + +// LoadSplitSpecFromReader loads split BTF from a reader. +// +// Types from base are used to resolve references in the split BTF. +// The returned Spec only contains types from the split BTF, not from the base. +func LoadSplitSpecFromReader(r io.ReaderAt, base *Spec) (*Spec, error) { + return loadRawSpec(r, internal.NativeEndian, base.types, base.strings) +} + +// TypesIterator iterates over types of a given spec. +type TypesIterator struct { + spec *Spec + index int + // The last visited type in the spec. + Type Type +} + +// Iterate returns the types iterator. +func (s *Spec) Iterate() *TypesIterator { + return &TypesIterator{spec: s, index: 0} +} + +// Next returns true as long as there are any remaining types. +func (iter *TypesIterator) Next() bool { + if len(iter.spec.types) <= iter.index { + return false + } + + iter.Type = iter.spec.types[iter.index] + iter.index++ + return true +} + +// Handle is a reference to BTF loaded into the kernel. +type Handle struct { + fd *sys.FD + + // Size of the raw BTF in bytes. + size uint32 +} + +// NewHandle loads BTF into the kernel. +// +// Returns ErrNotSupported if BTF is not supported. +func NewHandle(spec *Spec) (*Handle, error) { + if err := haveBTF(); err != nil { + return nil, err + } + + if spec.byteOrder != internal.NativeEndian { + return nil, fmt.Errorf("can't load %s BTF on %s", spec.byteOrder, internal.NativeEndian) + } + + btf, err := spec.marshal(marshalOpts{ + ByteOrder: internal.NativeEndian, + StripFuncLinkage: haveFuncLinkage() != nil, + }) + if err != nil { + return nil, fmt.Errorf("can't marshal BTF: %w", err) + } + + if uint64(len(btf)) > math.MaxUint32 { + return nil, errors.New("BTF exceeds the maximum size") + } + + attr := &sys.BtfLoadAttr{ + Btf: sys.NewSlicePointer(btf), + BtfSize: uint32(len(btf)), + } + + fd, err := sys.BtfLoad(attr) + if err != nil { + logBuf := make([]byte, 64*1024) + attr.BtfLogBuf = sys.NewSlicePointer(logBuf) + attr.BtfLogSize = uint32(len(logBuf)) + attr.BtfLogLevel = 1 + // NB: The syscall will never return ENOSPC as of 5.18-rc4. + _, _ = sys.BtfLoad(attr) + return nil, internal.ErrorWithLog(err, logBuf) + } + + return &Handle{fd, attr.BtfSize}, nil +} + +// NewHandleFromID returns the BTF handle for a given id. +// +// Prefer calling [ebpf.Program.Handle] or [ebpf.Map.Handle] if possible. +// +// Returns ErrNotExist, if there is no BTF with the given id. +// +// Requires CAP_SYS_ADMIN. +func NewHandleFromID(id ID) (*Handle, error) { + fd, err := sys.BtfGetFdById(&sys.BtfGetFdByIdAttr{ + Id: uint32(id), + }) + if err != nil { + return nil, fmt.Errorf("get FD for ID %d: %w", id, err) + } + + info, err := newHandleInfoFromFD(fd) + if err != nil { + _ = fd.Close() + return nil, err + } + + return &Handle{fd, info.size}, nil +} + +// Spec parses the kernel BTF into Go types. +// +// base is used to decode split BTF and may be nil. +func (h *Handle) Spec(base *Spec) (*Spec, error) { + var btfInfo sys.BtfInfo + btfBuffer := make([]byte, h.size) + btfInfo.Btf, btfInfo.BtfSize = sys.NewSlicePointerLen(btfBuffer) + + if err := sys.ObjInfo(h.fd, &btfInfo); err != nil { + return nil, err + } + + var baseTypes types + var baseStrings *stringTable + if base != nil { + baseTypes = base.types + baseStrings = base.strings + } + + return loadRawSpec(bytes.NewReader(btfBuffer), internal.NativeEndian, baseTypes, baseStrings) +} + +// Close destroys the handle. +// +// Subsequent calls to FD will return an invalid value. +func (h *Handle) Close() error { + if h == nil { + return nil + } + + return h.fd.Close() +} + +// FD returns the file descriptor for the handle. +func (h *Handle) FD() int { + return h.fd.Int() +} + +// Info returns metadata about the handle. +func (h *Handle) Info() (*HandleInfo, error) { + return newHandleInfoFromFD(h.fd) +} + +func marshalBTF(types interface{}, strings []byte, bo binary.ByteOrder) []byte { + const minHeaderLength = 24 + + typesLen := uint32(binary.Size(types)) + header := btfHeader{ + Magic: btfMagic, + Version: 1, + HdrLen: minHeaderLength, + TypeOff: 0, + TypeLen: typesLen, + StringOff: typesLen, + StringLen: uint32(len(strings)), + } + + buf := new(bytes.Buffer) + _ = binary.Write(buf, bo, &header) + _ = binary.Write(buf, bo, types) + buf.Write(strings) + + return buf.Bytes() +} + +var haveBTF = internal.FeatureTest("BTF", "5.1", func() error { + var ( + types struct { + Integer btfType + Var btfType + btfVar struct{ Linkage uint32 } + } + strings = []byte{0, 'a', 0} + ) + + // We use a BTF_KIND_VAR here, to make sure that + // the kernel understands BTF at least as well as we + // do. BTF_KIND_VAR was introduced ~5.1. + types.Integer.SetKind(kindPointer) + types.Var.NameOff = 1 + types.Var.SetKind(kindVar) + types.Var.SizeType = 1 + + btf := marshalBTF(&types, strings, internal.NativeEndian) + + fd, err := sys.BtfLoad(&sys.BtfLoadAttr{ + Btf: sys.NewSlicePointer(btf), + BtfSize: uint32(len(btf)), + }) + if errors.Is(err, unix.EINVAL) || errors.Is(err, unix.EPERM) { + // Treat both EINVAL and EPERM as not supported: loading the program + // might still succeed without BTF. + return internal.ErrNotSupported + } + if err != nil { + return err + } + + fd.Close() + return nil +}) + +var haveFuncLinkage = internal.FeatureTest("BTF func linkage", "5.6", func() error { + if err := haveBTF(); err != nil { + return err + } + + var ( + types struct { + FuncProto btfType + Func btfType + } + strings = []byte{0, 'a', 0} + ) + + types.FuncProto.SetKind(kindFuncProto) + types.Func.SetKind(kindFunc) + types.Func.SizeType = 1 // aka FuncProto + types.Func.NameOff = 1 + types.Func.SetLinkage(GlobalFunc) + + btf := marshalBTF(&types, strings, internal.NativeEndian) + + fd, err := sys.BtfLoad(&sys.BtfLoadAttr{ + Btf: sys.NewSlicePointer(btf), + BtfSize: uint32(len(btf)), + }) + if errors.Is(err, unix.EINVAL) { + return internal.ErrNotSupported + } + if err != nil { + return err + } + + fd.Close() + return nil +}) diff --git a/vendor/github.com/cilium/ebpf/btf/btf_types.go b/vendor/github.com/cilium/ebpf/btf/btf_types.go new file mode 100644 index 000000000..481018049 --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/btf_types.go @@ -0,0 +1,343 @@ +package btf + +import ( + "encoding/binary" + "fmt" + "io" +) + +//go:generate stringer -linecomment -output=btf_types_string.go -type=FuncLinkage,VarLinkage + +// btfKind describes a Type. +type btfKind uint8 + +// Equivalents of the BTF_KIND_* constants. +const ( + kindUnknown btfKind = iota + kindInt + kindPointer + kindArray + kindStruct + kindUnion + kindEnum + kindForward + kindTypedef + kindVolatile + kindConst + kindRestrict + // Added ~4.20 + kindFunc + kindFuncProto + // Added ~5.1 + kindVar + kindDatasec + // Added ~5.13 + kindFloat +) + +// FuncLinkage describes BTF function linkage metadata. +type FuncLinkage int + +// Equivalent of enum btf_func_linkage. +const ( + StaticFunc FuncLinkage = iota // static + GlobalFunc // global + ExternFunc // extern +) + +// VarLinkage describes BTF variable linkage metadata. +type VarLinkage int + +const ( + StaticVar VarLinkage = iota // static + GlobalVar // global + ExternVar // extern +) + +const ( + btfTypeKindShift = 24 + btfTypeKindLen = 5 + btfTypeVlenShift = 0 + btfTypeVlenMask = 16 + btfTypeKindFlagShift = 31 + btfTypeKindFlagMask = 1 +) + +// btfType is equivalent to struct btf_type in Documentation/bpf/btf.rst. +type btfType struct { + NameOff uint32 + /* "info" bits arrangement + * bits 0-15: vlen (e.g. # of struct's members), linkage + * bits 16-23: unused + * bits 24-28: kind (e.g. int, ptr, array...etc) + * bits 29-30: unused + * bit 31: kind_flag, currently used by + * struct, union and fwd + */ + Info uint32 + /* "size" is used by INT, ENUM, STRUCT and UNION. + * "size" tells the size of the type it is describing. + * + * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, + * FUNC and FUNC_PROTO. + * "type" is a type_id referring to another type. + */ + SizeType uint32 +} + +func (k btfKind) String() string { + switch k { + case kindUnknown: + return "Unknown" + case kindInt: + return "Integer" + case kindPointer: + return "Pointer" + case kindArray: + return "Array" + case kindStruct: + return "Struct" + case kindUnion: + return "Union" + case kindEnum: + return "Enumeration" + case kindForward: + return "Forward" + case kindTypedef: + return "Typedef" + case kindVolatile: + return "Volatile" + case kindConst: + return "Const" + case kindRestrict: + return "Restrict" + case kindFunc: + return "Function" + case kindFuncProto: + return "Function Proto" + case kindVar: + return "Variable" + case kindDatasec: + return "Section" + case kindFloat: + return "Float" + default: + return fmt.Sprintf("Unknown (%d)", k) + } +} + +func mask(len uint32) uint32 { + return (1 << len) - 1 +} + +func readBits(value, len, shift uint32) uint32 { + return (value >> shift) & mask(len) +} + +func writeBits(value, len, shift, new uint32) uint32 { + value &^= mask(len) << shift + value |= (new & mask(len)) << shift + return value +} + +func (bt *btfType) info(len, shift uint32) uint32 { + return readBits(bt.Info, len, shift) +} + +func (bt *btfType) setInfo(value, len, shift uint32) { + bt.Info = writeBits(bt.Info, len, shift, value) +} + +func (bt *btfType) Kind() btfKind { + return btfKind(bt.info(btfTypeKindLen, btfTypeKindShift)) +} + +func (bt *btfType) SetKind(kind btfKind) { + bt.setInfo(uint32(kind), btfTypeKindLen, btfTypeKindShift) +} + +func (bt *btfType) Vlen() int { + return int(bt.info(btfTypeVlenMask, btfTypeVlenShift)) +} + +func (bt *btfType) SetVlen(vlen int) { + bt.setInfo(uint32(vlen), btfTypeVlenMask, btfTypeVlenShift) +} + +func (bt *btfType) KindFlag() bool { + return bt.info(btfTypeKindFlagMask, btfTypeKindFlagShift) == 1 +} + +func (bt *btfType) Linkage() FuncLinkage { + return FuncLinkage(bt.info(btfTypeVlenMask, btfTypeVlenShift)) +} + +func (bt *btfType) SetLinkage(linkage FuncLinkage) { + bt.setInfo(uint32(linkage), btfTypeVlenMask, btfTypeVlenShift) +} + +func (bt *btfType) Type() TypeID { + // TODO: Panic here if wrong kind? + return TypeID(bt.SizeType) +} + +func (bt *btfType) Size() uint32 { + // TODO: Panic here if wrong kind? + return bt.SizeType +} + +func (bt *btfType) SetSize(size uint32) { + bt.SizeType = size +} + +type rawType struct { + btfType + data interface{} +} + +func (rt *rawType) Marshal(w io.Writer, bo binary.ByteOrder) error { + if err := binary.Write(w, bo, &rt.btfType); err != nil { + return err + } + + if rt.data == nil { + return nil + } + + return binary.Write(w, bo, rt.data) +} + +// btfInt encodes additional data for integers. +// +// ? ? ? ? e e e e o o o o o o o o ? ? ? ? ? ? ? ? b b b b b b b b +// ? = undefined +// e = encoding +// o = offset (bitfields?) +// b = bits (bitfields) +type btfInt struct { + Raw uint32 +} + +const ( + btfIntEncodingLen = 4 + btfIntEncodingShift = 24 + btfIntOffsetLen = 8 + btfIntOffsetShift = 16 + btfIntBitsLen = 8 + btfIntBitsShift = 0 +) + +func (bi btfInt) Encoding() IntEncoding { + return IntEncoding(readBits(bi.Raw, btfIntEncodingLen, btfIntEncodingShift)) +} + +func (bi *btfInt) SetEncoding(e IntEncoding) { + bi.Raw = writeBits(uint32(bi.Raw), btfIntEncodingLen, btfIntEncodingShift, uint32(e)) +} + +func (bi btfInt) Offset() Bits { + return Bits(readBits(bi.Raw, btfIntOffsetLen, btfIntOffsetShift)) +} + +func (bi *btfInt) SetOffset(offset uint32) { + bi.Raw = writeBits(bi.Raw, btfIntOffsetLen, btfIntOffsetShift, offset) +} + +func (bi btfInt) Bits() Bits { + return Bits(readBits(bi.Raw, btfIntBitsLen, btfIntBitsShift)) +} + +func (bi *btfInt) SetBits(bits byte) { + bi.Raw = writeBits(bi.Raw, btfIntBitsLen, btfIntBitsShift, uint32(bits)) +} + +type btfArray struct { + Type TypeID + IndexType TypeID + Nelems uint32 +} + +type btfMember struct { + NameOff uint32 + Type TypeID + Offset uint32 +} + +type btfVarSecinfo struct { + Type TypeID + Offset uint32 + Size uint32 +} + +type btfVariable struct { + Linkage uint32 +} + +type btfEnum struct { + NameOff uint32 + Val int32 +} + +type btfParam struct { + NameOff uint32 + Type TypeID +} + +func readTypes(r io.Reader, bo binary.ByteOrder, typeLen uint32) ([]rawType, error) { + var header btfType + // because of the interleaving between types and struct members it is difficult to + // precompute the numbers of raw types this will parse + // this "guess" is a good first estimation + sizeOfbtfType := uintptr(binary.Size(btfType{})) + tyMaxCount := uintptr(typeLen) / sizeOfbtfType / 2 + types := make([]rawType, 0, tyMaxCount) + + for id := TypeID(1); ; id++ { + if err := binary.Read(r, bo, &header); err == io.EOF { + return types, nil + } else if err != nil { + return nil, fmt.Errorf("can't read type info for id %v: %v", id, err) + } + + var data interface{} + switch header.Kind() { + case kindInt: + data = new(btfInt) + case kindPointer: + case kindArray: + data = new(btfArray) + case kindStruct: + fallthrough + case kindUnion: + data = make([]btfMember, header.Vlen()) + case kindEnum: + data = make([]btfEnum, header.Vlen()) + case kindForward: + case kindTypedef: + case kindVolatile: + case kindConst: + case kindRestrict: + case kindFunc: + case kindFuncProto: + data = make([]btfParam, header.Vlen()) + case kindVar: + data = new(btfVariable) + case kindDatasec: + data = make([]btfVarSecinfo, header.Vlen()) + case kindFloat: + default: + return nil, fmt.Errorf("type id %v: unknown kind: %v", id, header.Kind()) + } + + if data == nil { + types = append(types, rawType{header, nil}) + continue + } + + if err := binary.Read(r, bo, data); err != nil { + return nil, fmt.Errorf("type id %d: kind %v: can't read %T: %v", id, header.Kind(), data, err) + } + + types = append(types, rawType{header, data}) + } +} diff --git a/vendor/github.com/cilium/ebpf/btf/btf_types_string.go b/vendor/github.com/cilium/ebpf/btf/btf_types_string.go new file mode 100644 index 000000000..0e0c17d68 --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/btf_types_string.go @@ -0,0 +1,44 @@ +// Code generated by "stringer -linecomment -output=btf_types_string.go -type=FuncLinkage,VarLinkage"; DO NOT EDIT. + +package btf + +import "strconv" + +func _() { + // An "invalid array index" compiler error signifies that the constant values have changed. + // Re-run the stringer command to generate them again. + var x [1]struct{} + _ = x[StaticFunc-0] + _ = x[GlobalFunc-1] + _ = x[ExternFunc-2] +} + +const _FuncLinkage_name = "staticglobalextern" + +var _FuncLinkage_index = [...]uint8{0, 6, 12, 18} + +func (i FuncLinkage) String() string { + if i < 0 || i >= FuncLinkage(len(_FuncLinkage_index)-1) { + return "FuncLinkage(" + strconv.FormatInt(int64(i), 10) + ")" + } + return _FuncLinkage_name[_FuncLinkage_index[i]:_FuncLinkage_index[i+1]] +} +func _() { + // An "invalid array index" compiler error signifies that the constant values have changed. + // Re-run the stringer command to generate them again. + var x [1]struct{} + _ = x[StaticVar-0] + _ = x[GlobalVar-1] + _ = x[ExternVar-2] +} + +const _VarLinkage_name = "staticglobalextern" + +var _VarLinkage_index = [...]uint8{0, 6, 12, 18} + +func (i VarLinkage) String() string { + if i < 0 || i >= VarLinkage(len(_VarLinkage_index)-1) { + return "VarLinkage(" + strconv.FormatInt(int64(i), 10) + ")" + } + return _VarLinkage_name[_VarLinkage_index[i]:_VarLinkage_index[i+1]] +} diff --git a/vendor/github.com/cilium/ebpf/btf/core.go b/vendor/github.com/cilium/ebpf/btf/core.go new file mode 100644 index 000000000..c48754809 --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/core.go @@ -0,0 +1,972 @@ +package btf + +import ( + "encoding/binary" + "errors" + "fmt" + "math" + "reflect" + "strconv" + "strings" + + "github.com/cilium/ebpf/asm" +) + +// Code in this file is derived from libbpf, which is available under a BSD +// 2-Clause license. + +// COREFixup is the result of computing a CO-RE relocation for a target. +type COREFixup struct { + kind coreKind + local uint32 + target uint32 + // True if there is no valid fixup. The instruction is replaced with an + // invalid dummy. + poison bool + // True if the validation of the local value should be skipped. Used by + // some kinds of bitfield relocations. + skipLocalValidation bool +} + +func (f *COREFixup) equal(other COREFixup) bool { + return f.local == other.local && f.target == other.target +} + +func (f *COREFixup) String() string { + if f.poison { + return fmt.Sprintf("%s=poison", f.kind) + } + return fmt.Sprintf("%s=%d->%d", f.kind, f.local, f.target) +} + +func (f *COREFixup) Apply(ins *asm.Instruction) error { + if f.poison { + const badRelo = 0xbad2310 + + *ins = asm.BuiltinFunc(badRelo).Call() + return nil + } + + switch class := ins.OpCode.Class(); class { + case asm.LdXClass, asm.StClass, asm.StXClass: + if want := int16(f.local); !f.skipLocalValidation && want != ins.Offset { + return fmt.Errorf("invalid offset %d, expected %d", ins.Offset, f.local) + } + + if f.target > math.MaxInt16 { + return fmt.Errorf("offset %d exceeds MaxInt16", f.target) + } + + ins.Offset = int16(f.target) + + case asm.LdClass: + if !ins.IsConstantLoad(asm.DWord) { + return fmt.Errorf("not a dword-sized immediate load") + } + + if want := int64(f.local); !f.skipLocalValidation && want != ins.Constant { + return fmt.Errorf("invalid immediate %d, expected %d (fixup: %v)", ins.Constant, want, f) + } + + ins.Constant = int64(f.target) + + case asm.ALUClass: + if ins.OpCode.ALUOp() == asm.Swap { + return fmt.Errorf("relocation against swap") + } + + fallthrough + + case asm.ALU64Class: + if src := ins.OpCode.Source(); src != asm.ImmSource { + return fmt.Errorf("invalid source %s", src) + } + + if want := int64(f.local); !f.skipLocalValidation && want != ins.Constant { + return fmt.Errorf("invalid immediate %d, expected %d (fixup: %v, kind: %v, ins: %v)", ins.Constant, want, f, f.kind, ins) + } + + if f.target > math.MaxInt32 { + return fmt.Errorf("immediate %d exceeds MaxInt32", f.target) + } + + ins.Constant = int64(f.target) + + default: + return fmt.Errorf("invalid class %s", class) + } + + return nil +} + +func (f COREFixup) isNonExistant() bool { + return f.kind.checksForExistence() && f.target == 0 +} + +// coreKind is the type of CO-RE relocation as specified in BPF source code. +type coreKind uint32 + +const ( + reloFieldByteOffset coreKind = iota /* field byte offset */ + reloFieldByteSize /* field size in bytes */ + reloFieldExists /* field existence in target kernel */ + reloFieldSigned /* field signedness (0 - unsigned, 1 - signed) */ + reloFieldLShiftU64 /* bitfield-specific left bitshift */ + reloFieldRShiftU64 /* bitfield-specific right bitshift */ + reloTypeIDLocal /* type ID in local BPF object */ + reloTypeIDTarget /* type ID in target kernel */ + reloTypeExists /* type existence in target kernel */ + reloTypeSize /* type size in bytes */ + reloEnumvalExists /* enum value existence in target kernel */ + reloEnumvalValue /* enum value integer value */ +) + +func (k coreKind) checksForExistence() bool { + return k == reloEnumvalExists || k == reloTypeExists || k == reloFieldExists +} + +func (k coreKind) String() string { + switch k { + case reloFieldByteOffset: + return "byte_off" + case reloFieldByteSize: + return "byte_sz" + case reloFieldExists: + return "field_exists" + case reloFieldSigned: + return "signed" + case reloFieldLShiftU64: + return "lshift_u64" + case reloFieldRShiftU64: + return "rshift_u64" + case reloTypeIDLocal: + return "local_type_id" + case reloTypeIDTarget: + return "target_type_id" + case reloTypeExists: + return "type_exists" + case reloTypeSize: + return "type_size" + case reloEnumvalExists: + return "enumval_exists" + case reloEnumvalValue: + return "enumval_value" + default: + return "unknown" + } +} + +// CORERelocate calculates the difference in types between local and target. +// +// Returns a list of fixups which can be applied to instructions to make them +// match the target type(s). +// +// Fixups are returned in the order of relos, e.g. fixup[i] is the solution +// for relos[i]. +func CORERelocate(local, target *Spec, relos []*CORERelocation) ([]COREFixup, error) { + if local.byteOrder != target.byteOrder { + return nil, fmt.Errorf("can't relocate %s against %s", local.byteOrder, target.byteOrder) + } + + type reloGroup struct { + relos []*CORERelocation + // Position of each relocation in relos. + indices []int + } + + // Split relocations into per Type lists. + relosByType := make(map[Type]*reloGroup) + result := make([]COREFixup, len(relos)) + for i, relo := range relos { + if relo.kind == reloTypeIDLocal { + // Filtering out reloTypeIDLocal here makes our lives a lot easier + // down the line, since it doesn't have a target at all. + if len(relo.accessor) > 1 || relo.accessor[0] != 0 { + return nil, fmt.Errorf("%s: unexpected accessor %v", relo.kind, relo.accessor) + } + + id, err := local.TypeID(relo.typ) + if err != nil { + return nil, fmt.Errorf("%s: %w", relo.kind, err) + } + + result[i] = COREFixup{ + kind: relo.kind, + local: uint32(id), + target: uint32(id), + } + continue + } + + group, ok := relosByType[relo.typ] + if !ok { + group = &reloGroup{} + relosByType[relo.typ] = group + } + group.relos = append(group.relos, relo) + group.indices = append(group.indices, i) + } + + for localType, group := range relosByType { + localTypeName := localType.TypeName() + if localTypeName == "" { + return nil, fmt.Errorf("relocate unnamed or anonymous type %s: %w", localType, ErrNotSupported) + } + + targets := target.namedTypes[newEssentialName(localTypeName)] + fixups, err := coreCalculateFixups(local, target, localType, targets, group.relos) + if err != nil { + return nil, fmt.Errorf("relocate %s: %w", localType, err) + } + + for j, index := range group.indices { + result[index] = fixups[j] + } + } + + return result, nil +} + +var errAmbiguousRelocation = errors.New("ambiguous relocation") +var errImpossibleRelocation = errors.New("impossible relocation") + +// coreCalculateFixups calculates the fixups for the given relocations using +// the "best" target. +// +// The best target is determined by scoring: the less poisoning we have to do +// the better the target is. +func coreCalculateFixups(localSpec, targetSpec *Spec, local Type, targets []Type, relos []*CORERelocation) ([]COREFixup, error) { + localID, err := localSpec.TypeID(local) + if err != nil { + return nil, fmt.Errorf("local type ID: %w", err) + } + local = Copy(local, UnderlyingType) + + bestScore := len(relos) + var bestFixups []COREFixup + for i := range targets { + targetID, err := targetSpec.TypeID(targets[i]) + if err != nil { + return nil, fmt.Errorf("target type ID: %w", err) + } + target := Copy(targets[i], UnderlyingType) + + score := 0 // lower is better + fixups := make([]COREFixup, 0, len(relos)) + for _, relo := range relos { + fixup, err := coreCalculateFixup(localSpec.byteOrder, local, localID, target, targetID, relo) + if err != nil { + return nil, fmt.Errorf("target %s: %w", target, err) + } + if fixup.poison || fixup.isNonExistant() { + score++ + } + fixups = append(fixups, fixup) + } + + if score > bestScore { + // We have a better target already, ignore this one. + continue + } + + if score < bestScore { + // This is the best target yet, use it. + bestScore = score + bestFixups = fixups + continue + } + + // Some other target has the same score as the current one. Make sure + // the fixups agree with each other. + for i, fixup := range bestFixups { + if !fixup.equal(fixups[i]) { + return nil, fmt.Errorf("%s: multiple types match: %w", fixup.kind, errAmbiguousRelocation) + } + } + } + + if bestFixups == nil { + // Nothing at all matched, probably because there are no suitable + // targets at all. + // + // Poison everything except checksForExistence. + bestFixups = make([]COREFixup, len(relos)) + for i, relo := range relos { + if relo.kind.checksForExistence() { + bestFixups[i] = COREFixup{kind: relo.kind, local: 1, target: 0} + } else { + bestFixups[i] = COREFixup{kind: relo.kind, poison: true} + } + } + } + + return bestFixups, nil +} + +// coreCalculateFixup calculates the fixup for a single local type, target type +// and relocation. +func coreCalculateFixup(byteOrder binary.ByteOrder, local Type, localID TypeID, target Type, targetID TypeID, relo *CORERelocation) (COREFixup, error) { + fixup := func(local, target uint32) (COREFixup, error) { + return COREFixup{kind: relo.kind, local: local, target: target}, nil + } + fixupWithoutValidation := func(local, target uint32) (COREFixup, error) { + return COREFixup{kind: relo.kind, local: local, target: target, skipLocalValidation: true}, nil + } + poison := func() (COREFixup, error) { + if relo.kind.checksForExistence() { + return fixup(1, 0) + } + return COREFixup{kind: relo.kind, poison: true}, nil + } + zero := COREFixup{} + + switch relo.kind { + case reloTypeIDTarget, reloTypeSize, reloTypeExists: + if len(relo.accessor) > 1 || relo.accessor[0] != 0 { + return zero, fmt.Errorf("%s: unexpected accessor %v", relo.kind, relo.accessor) + } + + err := coreAreTypesCompatible(local, target) + if errors.Is(err, errImpossibleRelocation) { + return poison() + } + if err != nil { + return zero, fmt.Errorf("relocation %s: %w", relo.kind, err) + } + + switch relo.kind { + case reloTypeExists: + return fixup(1, 1) + + case reloTypeIDTarget: + return fixup(uint32(localID), uint32(targetID)) + + case reloTypeSize: + localSize, err := Sizeof(local) + if err != nil { + return zero, err + } + + targetSize, err := Sizeof(target) + if err != nil { + return zero, err + } + + return fixup(uint32(localSize), uint32(targetSize)) + } + + case reloEnumvalValue, reloEnumvalExists: + localValue, targetValue, err := coreFindEnumValue(local, relo.accessor, target) + if errors.Is(err, errImpossibleRelocation) { + return poison() + } + if err != nil { + return zero, fmt.Errorf("relocation %s: %w", relo.kind, err) + } + + switch relo.kind { + case reloEnumvalExists: + return fixup(1, 1) + + case reloEnumvalValue: + return fixup(uint32(localValue.Value), uint32(targetValue.Value)) + } + + case reloFieldSigned: + switch local.(type) { + case *Enum: + return fixup(1, 1) + case *Int: + return fixup( + uint32(local.(*Int).Encoding&Signed), + uint32(target.(*Int).Encoding&Signed), + ) + default: + return fixupWithoutValidation(0, 0) + } + + case reloFieldByteOffset, reloFieldByteSize, reloFieldExists, reloFieldLShiftU64, reloFieldRShiftU64: + if _, ok := target.(*Fwd); ok { + // We can't relocate fields using a forward declaration, so + // skip it. If a non-forward declaration is present in the BTF + // we'll find it in one of the other iterations. + return poison() + } + + localField, targetField, err := coreFindField(local, relo.accessor, target) + if errors.Is(err, errImpossibleRelocation) { + return poison() + } + if err != nil { + return zero, fmt.Errorf("target %s: %w", target, err) + } + + maybeSkipValidation := func(f COREFixup, err error) (COREFixup, error) { + f.skipLocalValidation = localField.bitfieldSize > 0 + return f, err + } + + switch relo.kind { + case reloFieldExists: + return fixup(1, 1) + + case reloFieldByteOffset: + return maybeSkipValidation(fixup(localField.offset, targetField.offset)) + + case reloFieldByteSize: + localSize, err := Sizeof(localField.Type) + if err != nil { + return zero, err + } + + targetSize, err := Sizeof(targetField.Type) + if err != nil { + return zero, err + } + return maybeSkipValidation(fixup(uint32(localSize), uint32(targetSize))) + + case reloFieldLShiftU64: + var target uint32 + if byteOrder == binary.LittleEndian { + targetSize, err := targetField.sizeBits() + if err != nil { + return zero, err + } + + target = uint32(64 - targetField.bitfieldOffset - targetSize) + } else { + loadWidth, err := Sizeof(targetField.Type) + if err != nil { + return zero, err + } + + target = uint32(64 - Bits(loadWidth*8) + targetField.bitfieldOffset) + } + return fixupWithoutValidation(0, target) + + case reloFieldRShiftU64: + targetSize, err := targetField.sizeBits() + if err != nil { + return zero, err + } + + return fixupWithoutValidation(0, uint32(64-targetSize)) + } + } + + return zero, fmt.Errorf("relocation %s: %w", relo.kind, ErrNotSupported) +} + +/* coreAccessor contains a path through a struct. It contains at least one index. + * + * The interpretation depends on the kind of the relocation. The following is + * taken from struct bpf_core_relo in libbpf_internal.h: + * + * - for field-based relocations, string encodes an accessed field using + * a sequence of field and array indices, separated by colon (:). It's + * conceptually very close to LLVM's getelementptr ([0]) instruction's + * arguments for identifying offset to a field. + * - for type-based relocations, strings is expected to be just "0"; + * - for enum value-based relocations, string contains an index of enum + * value within its enum type; + * + * Example to provide a better feel. + * + * struct sample { + * int a; + * struct { + * int b[10]; + * }; + * }; + * + * struct sample s = ...; + * int x = &s->a; // encoded as "0:0" (a is field #0) + * int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1, + * // b is field #0 inside anon struct, accessing elem #5) + * int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array) + */ +type coreAccessor []int + +func parseCOREAccessor(accessor string) (coreAccessor, error) { + if accessor == "" { + return nil, fmt.Errorf("empty accessor") + } + + parts := strings.Split(accessor, ":") + result := make(coreAccessor, 0, len(parts)) + for _, part := range parts { + // 31 bits to avoid overflowing int on 32 bit platforms. + index, err := strconv.ParseUint(part, 10, 31) + if err != nil { + return nil, fmt.Errorf("accessor index %q: %s", part, err) + } + + result = append(result, int(index)) + } + + return result, nil +} + +func (ca coreAccessor) String() string { + strs := make([]string, 0, len(ca)) + for _, i := range ca { + strs = append(strs, strconv.Itoa(i)) + } + return strings.Join(strs, ":") +} + +func (ca coreAccessor) enumValue(t Type) (*EnumValue, error) { + e, ok := t.(*Enum) + if !ok { + return nil, fmt.Errorf("not an enum: %s", t) + } + + if len(ca) > 1 { + return nil, fmt.Errorf("invalid accessor %s for enum", ca) + } + + i := ca[0] + if i >= len(e.Values) { + return nil, fmt.Errorf("invalid index %d for %s", i, e) + } + + return &e.Values[i], nil +} + +// coreField represents the position of a "child" of a composite type from the +// start of that type. +// +// /- start of composite +// | offset * 8 | bitfieldOffset | bitfieldSize | ... | +// \- start of field end of field -/ +type coreField struct { + Type Type + + // The position of the field from the start of the composite type in bytes. + offset uint32 + + // The offset of the bitfield in bits from the start of the field. + bitfieldOffset Bits + + // The size of the bitfield in bits. + // + // Zero if the field is not a bitfield. + bitfieldSize Bits +} + +func (cf *coreField) adjustOffsetToNthElement(n int) error { + size, err := Sizeof(cf.Type) + if err != nil { + return err + } + + cf.offset += uint32(n) * uint32(size) + return nil +} + +func (cf *coreField) adjustOffsetBits(offset Bits) error { + align, err := alignof(cf.Type) + if err != nil { + return err + } + + // We can compute the load offset by: + // 1) converting the bit offset to bytes with a flooring division. + // 2) dividing and multiplying that offset by the alignment, yielding the + // load size aligned offset. + offsetBytes := uint32(offset/8) / uint32(align) * uint32(align) + + // The number of bits remaining is the bit offset less the number of bits + // we can "skip" with the aligned offset. + cf.bitfieldOffset = offset - Bits(offsetBytes*8) + + // We know that cf.offset is aligned at to at least align since we get it + // from the compiler via BTF. Adding an aligned offsetBytes preserves the + // alignment. + cf.offset += offsetBytes + return nil +} + +func (cf *coreField) sizeBits() (Bits, error) { + if cf.bitfieldSize > 0 { + return cf.bitfieldSize, nil + } + + // Someone is trying to access a non-bitfield via a bit shift relocation. + // This happens when a field changes from a bitfield to a regular field + // between kernel versions. Synthesise the size to make the shifts work. + size, err := Sizeof(cf.Type) + if err != nil { + return 0, nil + } + return Bits(size * 8), nil +} + +// coreFindField descends into the local type using the accessor and tries to +// find an equivalent field in target at each step. +// +// Returns the field and the offset of the field from the start of +// target in bits. +func coreFindField(localT Type, localAcc coreAccessor, targetT Type) (coreField, coreField, error) { + local := coreField{Type: localT} + target := coreField{Type: targetT} + + // The first index is used to offset a pointer of the base type like + // when accessing an array. + if err := local.adjustOffsetToNthElement(localAcc[0]); err != nil { + return coreField{}, coreField{}, err + } + + if err := target.adjustOffsetToNthElement(localAcc[0]); err != nil { + return coreField{}, coreField{}, err + } + + if err := coreAreMembersCompatible(local.Type, target.Type); err != nil { + return coreField{}, coreField{}, fmt.Errorf("fields: %w", err) + } + + var localMaybeFlex, targetMaybeFlex bool + for i, acc := range localAcc[1:] { + switch localType := local.Type.(type) { + case composite: + // For composite types acc is used to find the field in the local type, + // and then we try to find a field in target with the same name. + localMembers := localType.members() + if acc >= len(localMembers) { + return coreField{}, coreField{}, fmt.Errorf("invalid accessor %d for %s", acc, localType) + } + + localMember := localMembers[acc] + if localMember.Name == "" { + _, ok := localMember.Type.(composite) + if !ok { + return coreField{}, coreField{}, fmt.Errorf("unnamed field with type %s: %s", localMember.Type, ErrNotSupported) + } + + // This is an anonymous struct or union, ignore it. + local = coreField{ + Type: localMember.Type, + offset: local.offset + localMember.Offset.Bytes(), + } + localMaybeFlex = false + continue + } + + targetType, ok := target.Type.(composite) + if !ok { + return coreField{}, coreField{}, fmt.Errorf("target not composite: %w", errImpossibleRelocation) + } + + targetMember, last, err := coreFindMember(targetType, localMember.Name) + if err != nil { + return coreField{}, coreField{}, err + } + + local = coreField{ + Type: localMember.Type, + offset: local.offset, + bitfieldSize: localMember.BitfieldSize, + } + localMaybeFlex = acc == len(localMembers)-1 + + target = coreField{ + Type: targetMember.Type, + offset: target.offset, + bitfieldSize: targetMember.BitfieldSize, + } + targetMaybeFlex = last + + if local.bitfieldSize == 0 && target.bitfieldSize == 0 { + local.offset += localMember.Offset.Bytes() + target.offset += targetMember.Offset.Bytes() + break + } + + // Either of the members is a bitfield. Make sure we're at the + // end of the accessor. + if next := i + 1; next < len(localAcc[1:]) { + return coreField{}, coreField{}, fmt.Errorf("can't descend into bitfield") + } + + if err := local.adjustOffsetBits(localMember.Offset); err != nil { + return coreField{}, coreField{}, err + } + + if err := target.adjustOffsetBits(targetMember.Offset); err != nil { + return coreField{}, coreField{}, err + } + + case *Array: + // For arrays, acc is the index in the target. + targetType, ok := target.Type.(*Array) + if !ok { + return coreField{}, coreField{}, fmt.Errorf("target not array: %w", errImpossibleRelocation) + } + + if localType.Nelems == 0 && !localMaybeFlex { + return coreField{}, coreField{}, fmt.Errorf("local type has invalid flexible array") + } + if targetType.Nelems == 0 && !targetMaybeFlex { + return coreField{}, coreField{}, fmt.Errorf("target type has invalid flexible array") + } + + if localType.Nelems > 0 && acc >= int(localType.Nelems) { + return coreField{}, coreField{}, fmt.Errorf("invalid access of %s at index %d", localType, acc) + } + if targetType.Nelems > 0 && acc >= int(targetType.Nelems) { + return coreField{}, coreField{}, fmt.Errorf("out of bounds access of target: %w", errImpossibleRelocation) + } + + local = coreField{ + Type: localType.Type, + offset: local.offset, + } + localMaybeFlex = false + + if err := local.adjustOffsetToNthElement(acc); err != nil { + return coreField{}, coreField{}, err + } + + target = coreField{ + Type: targetType.Type, + offset: target.offset, + } + targetMaybeFlex = false + + if err := target.adjustOffsetToNthElement(acc); err != nil { + return coreField{}, coreField{}, err + } + + default: + return coreField{}, coreField{}, fmt.Errorf("relocate field of %T: %w", localType, ErrNotSupported) + } + + if err := coreAreMembersCompatible(local.Type, target.Type); err != nil { + return coreField{}, coreField{}, err + } + } + + return local, target, nil +} + +// coreFindMember finds a member in a composite type while handling anonymous +// structs and unions. +func coreFindMember(typ composite, name string) (Member, bool, error) { + if name == "" { + return Member{}, false, errors.New("can't search for anonymous member") + } + + type offsetTarget struct { + composite + offset Bits + } + + targets := []offsetTarget{{typ, 0}} + visited := make(map[composite]bool) + + for i := 0; i < len(targets); i++ { + target := targets[i] + + // Only visit targets once to prevent infinite recursion. + if visited[target] { + continue + } + if len(visited) >= maxTypeDepth { + // This check is different than libbpf, which restricts the entire + // path to BPF_CORE_SPEC_MAX_LEN items. + return Member{}, false, fmt.Errorf("type is nested too deep") + } + visited[target] = true + + members := target.members() + for j, member := range members { + if member.Name == name { + // NB: This is safe because member is a copy. + member.Offset += target.offset + return member, j == len(members)-1, nil + } + + // The names don't match, but this member could be an anonymous struct + // or union. + if member.Name != "" { + continue + } + + comp, ok := member.Type.(composite) + if !ok { + return Member{}, false, fmt.Errorf("anonymous non-composite type %T not allowed", member.Type) + } + + targets = append(targets, offsetTarget{comp, target.offset + member.Offset}) + } + } + + return Member{}, false, fmt.Errorf("no matching member: %w", errImpossibleRelocation) +} + +// coreFindEnumValue follows localAcc to find the equivalent enum value in target. +func coreFindEnumValue(local Type, localAcc coreAccessor, target Type) (localValue, targetValue *EnumValue, _ error) { + localValue, err := localAcc.enumValue(local) + if err != nil { + return nil, nil, err + } + + targetEnum, ok := target.(*Enum) + if !ok { + return nil, nil, errImpossibleRelocation + } + + localName := newEssentialName(localValue.Name) + for i, targetValue := range targetEnum.Values { + if newEssentialName(targetValue.Name) != localName { + continue + } + + return localValue, &targetEnum.Values[i], nil + } + + return nil, nil, errImpossibleRelocation +} + +/* The comment below is from bpf_core_types_are_compat in libbpf.c: + * + * Check local and target types for compatibility. This check is used for + * type-based CO-RE relocations and follow slightly different rules than + * field-based relocations. This function assumes that root types were already + * checked for name match. Beyond that initial root-level name check, names + * are completely ignored. Compatibility rules are as follows: + * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but + * kind should match for local and target types (i.e., STRUCT is not + * compatible with UNION); + * - for ENUMs, the size is ignored; + * - for INT, size and signedness are ignored; + * - for ARRAY, dimensionality is ignored, element types are checked for + * compatibility recursively; + * - CONST/VOLATILE/RESTRICT modifiers are ignored; + * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible; + * - FUNC_PROTOs are compatible if they have compatible signature: same + * number of input args and compatible return and argument types. + * These rules are not set in stone and probably will be adjusted as we get + * more experience with using BPF CO-RE relocations. + * + * Returns errImpossibleRelocation if types are not compatible. + */ +func coreAreTypesCompatible(localType Type, targetType Type) error { + var ( + localTs, targetTs typeDeque + l, t = &localType, &targetType + depth = 0 + ) + + for ; l != nil && t != nil; l, t = localTs.shift(), targetTs.shift() { + if depth >= maxTypeDepth { + return errors.New("types are nested too deep") + } + + localType = *l + targetType = *t + + if reflect.TypeOf(localType) != reflect.TypeOf(targetType) { + return fmt.Errorf("type mismatch: %w", errImpossibleRelocation) + } + + switch lv := (localType).(type) { + case *Void, *Struct, *Union, *Enum, *Fwd, *Int: + // Nothing to do here + + case *Pointer, *Array: + depth++ + localType.walk(&localTs) + targetType.walk(&targetTs) + + case *FuncProto: + tv := targetType.(*FuncProto) + if len(lv.Params) != len(tv.Params) { + return fmt.Errorf("function param mismatch: %w", errImpossibleRelocation) + } + + depth++ + localType.walk(&localTs) + targetType.walk(&targetTs) + + default: + return fmt.Errorf("unsupported type %T", localType) + } + } + + if l != nil { + return fmt.Errorf("dangling local type %T", *l) + } + + if t != nil { + return fmt.Errorf("dangling target type %T", *t) + } + + return nil +} + +/* coreAreMembersCompatible checks two types for field-based relocation compatibility. + * + * The comment below is from bpf_core_fields_are_compat in libbpf.c: + * + * Check two types for compatibility for the purpose of field access + * relocation. const/volatile/restrict and typedefs are skipped to ensure we + * are relocating semantically compatible entities: + * - any two STRUCTs/UNIONs are compatible and can be mixed; + * - any two FWDs are compatible, if their names match (modulo flavor suffix); + * - any two PTRs are always compatible; + * - for ENUMs, names should be the same (ignoring flavor suffix) or at + * least one of enums should be anonymous; + * - for ENUMs, check sizes, names are ignored; + * - for INT, size and signedness are ignored; + * - any two FLOATs are always compatible; + * - for ARRAY, dimensionality is ignored, element types are checked for + * compatibility recursively; + * [ NB: coreAreMembersCompatible doesn't recurse, this check is done + * by coreFindField. ] + * - everything else shouldn't be ever a target of relocation. + * These rules are not set in stone and probably will be adjusted as we get + * more experience with using BPF CO-RE relocations. + * + * Returns errImpossibleRelocation if the members are not compatible. + */ +func coreAreMembersCompatible(localType Type, targetType Type) error { + doNamesMatch := func(a, b string) error { + if a == "" || b == "" { + // allow anonymous and named type to match + return nil + } + + if newEssentialName(a) == newEssentialName(b) { + return nil + } + + return fmt.Errorf("names don't match: %w", errImpossibleRelocation) + } + + _, lok := localType.(composite) + _, tok := targetType.(composite) + if lok && tok { + return nil + } + + if reflect.TypeOf(localType) != reflect.TypeOf(targetType) { + return fmt.Errorf("type mismatch: %w", errImpossibleRelocation) + } + + switch lv := localType.(type) { + case *Array, *Pointer, *Float, *Int: + return nil + + case *Enum: + tv := targetType.(*Enum) + return doNamesMatch(lv.Name, tv.Name) + + case *Fwd: + tv := targetType.(*Fwd) + return doNamesMatch(lv.Name, tv.Name) + + default: + return fmt.Errorf("type %s: %w", localType, ErrNotSupported) + } +} diff --git a/vendor/github.com/cilium/ebpf/btf/doc.go b/vendor/github.com/cilium/ebpf/btf/doc.go new file mode 100644 index 000000000..b1f4b1fc3 --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/doc.go @@ -0,0 +1,5 @@ +// Package btf handles data encoded according to the BPF Type Format. +// +// The canonical documentation lives in the Linux kernel repository and is +// available at https://www.kernel.org/doc/html/latest/bpf/btf.html +package btf diff --git a/vendor/github.com/cilium/ebpf/btf/ext_info.go b/vendor/github.com/cilium/ebpf/btf/ext_info.go new file mode 100644 index 000000000..2c0e1afe2 --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/ext_info.go @@ -0,0 +1,721 @@ +package btf + +import ( + "bytes" + "encoding/binary" + "errors" + "fmt" + "io" + "math" + "sort" + + "github.com/cilium/ebpf/asm" + "github.com/cilium/ebpf/internal" +) + +// ExtInfos contains ELF section metadata. +type ExtInfos struct { + // The slices are sorted by offset in ascending order. + funcInfos map[string][]funcInfo + lineInfos map[string][]lineInfo + relocationInfos map[string][]coreRelocationInfo +} + +// loadExtInfosFromELF parses ext infos from the .BTF.ext section in an ELF. +// +// Returns an error wrapping ErrNotFound if no ext infos are present. +func loadExtInfosFromELF(file *internal.SafeELFFile, ts types, strings *stringTable) (*ExtInfos, error) { + section := file.Section(".BTF.ext") + if section == nil { + return nil, fmt.Errorf("btf ext infos: %w", ErrNotFound) + } + + if section.ReaderAt == nil { + return nil, fmt.Errorf("compressed ext_info is not supported") + } + + return loadExtInfos(section.ReaderAt, file.ByteOrder, ts, strings) +} + +// loadExtInfos parses bare ext infos. +func loadExtInfos(r io.ReaderAt, bo binary.ByteOrder, ts types, strings *stringTable) (*ExtInfos, error) { + // Open unbuffered section reader. binary.Read() calls io.ReadFull on + // the header structs, resulting in one syscall per header. + headerRd := io.NewSectionReader(r, 0, math.MaxInt64) + extHeader, err := parseBTFExtHeader(headerRd, bo) + if err != nil { + return nil, fmt.Errorf("parsing BTF extension header: %w", err) + } + + coreHeader, err := parseBTFExtCOREHeader(headerRd, bo, extHeader) + if err != nil { + return nil, fmt.Errorf("parsing BTF CO-RE header: %w", err) + } + + buf := internal.NewBufferedSectionReader(r, extHeader.funcInfoStart(), int64(extHeader.FuncInfoLen)) + btfFuncInfos, err := parseFuncInfos(buf, bo, strings) + if err != nil { + return nil, fmt.Errorf("parsing BTF function info: %w", err) + } + + funcInfos := make(map[string][]funcInfo, len(btfFuncInfos)) + for section, bfis := range btfFuncInfos { + funcInfos[section], err = newFuncInfos(bfis, ts) + if err != nil { + return nil, fmt.Errorf("section %s: func infos: %w", section, err) + } + } + + buf = internal.NewBufferedSectionReader(r, extHeader.lineInfoStart(), int64(extHeader.LineInfoLen)) + btfLineInfos, err := parseLineInfos(buf, bo, strings) + if err != nil { + return nil, fmt.Errorf("parsing BTF line info: %w", err) + } + + lineInfos := make(map[string][]lineInfo, len(btfLineInfos)) + for section, blis := range btfLineInfos { + lineInfos[section], err = newLineInfos(blis, strings) + if err != nil { + return nil, fmt.Errorf("section %s: line infos: %w", section, err) + } + } + + if coreHeader == nil || coreHeader.COREReloLen == 0 { + return &ExtInfos{funcInfos, lineInfos, nil}, nil + } + + var btfCORERelos map[string][]bpfCORERelo + buf = internal.NewBufferedSectionReader(r, extHeader.coreReloStart(coreHeader), int64(coreHeader.COREReloLen)) + btfCORERelos, err = parseCORERelos(buf, bo, strings) + if err != nil { + return nil, fmt.Errorf("parsing CO-RE relocation info: %w", err) + } + + coreRelos := make(map[string][]coreRelocationInfo, len(btfCORERelos)) + for section, brs := range btfCORERelos { + coreRelos[section], err = newRelocationInfos(brs, ts, strings) + if err != nil { + return nil, fmt.Errorf("section %s: CO-RE relocations: %w", section, err) + } + } + + return &ExtInfos{funcInfos, lineInfos, coreRelos}, nil +} + +type funcInfoMeta struct{} +type coreRelocationMeta struct{} + +// Assign per-section metadata from BTF to a section's instructions. +func (ei *ExtInfos) Assign(insns asm.Instructions, section string) { + funcInfos := ei.funcInfos[section] + lineInfos := ei.lineInfos[section] + reloInfos := ei.relocationInfos[section] + + iter := insns.Iterate() + for iter.Next() { + if len(funcInfos) > 0 && funcInfos[0].offset == iter.Offset { + iter.Ins.Metadata.Set(funcInfoMeta{}, funcInfos[0].fn) + funcInfos = funcInfos[1:] + } + + if len(lineInfos) > 0 && lineInfos[0].offset == iter.Offset { + *iter.Ins = iter.Ins.WithSource(lineInfos[0].line) + lineInfos = lineInfos[1:] + } + + if len(reloInfos) > 0 && reloInfos[0].offset == iter.Offset { + iter.Ins.Metadata.Set(coreRelocationMeta{}, reloInfos[0].relo) + reloInfos = reloInfos[1:] + } + } +} + +// MarshalExtInfos encodes function and line info embedded in insns into kernel +// wire format. +func MarshalExtInfos(insns asm.Instructions, typeID func(Type) (TypeID, error)) (funcInfos, lineInfos []byte, _ error) { + iter := insns.Iterate() + var fiBuf, liBuf bytes.Buffer + for iter.Next() { + if fn := FuncMetadata(iter.Ins); fn != nil { + fi := &funcInfo{ + fn: fn, + offset: iter.Offset, + } + if err := fi.marshal(&fiBuf, typeID); err != nil { + return nil, nil, fmt.Errorf("write func info: %w", err) + } + } + + if line, ok := iter.Ins.Source().(*Line); ok { + li := &lineInfo{ + line: line, + offset: iter.Offset, + } + if err := li.marshal(&liBuf); err != nil { + return nil, nil, fmt.Errorf("write line info: %w", err) + } + } + } + return fiBuf.Bytes(), liBuf.Bytes(), nil +} + +// btfExtHeader is found at the start of the .BTF.ext section. +type btfExtHeader struct { + Magic uint16 + Version uint8 + Flags uint8 + + // HdrLen is larger than the size of struct btfExtHeader when it is + // immediately followed by a btfExtCOREHeader. + HdrLen uint32 + + FuncInfoOff uint32 + FuncInfoLen uint32 + LineInfoOff uint32 + LineInfoLen uint32 +} + +// parseBTFExtHeader parses the header of the .BTF.ext section. +func parseBTFExtHeader(r io.Reader, bo binary.ByteOrder) (*btfExtHeader, error) { + var header btfExtHeader + if err := binary.Read(r, bo, &header); err != nil { + return nil, fmt.Errorf("can't read header: %v", err) + } + + if header.Magic != btfMagic { + return nil, fmt.Errorf("incorrect magic value %v", header.Magic) + } + + if header.Version != 1 { + return nil, fmt.Errorf("unexpected version %v", header.Version) + } + + if header.Flags != 0 { + return nil, fmt.Errorf("unsupported flags %v", header.Flags) + } + + if int64(header.HdrLen) < int64(binary.Size(&header)) { + return nil, fmt.Errorf("header length shorter than btfExtHeader size") + } + + return &header, nil +} + +// funcInfoStart returns the offset from the beginning of the .BTF.ext section +// to the start of its func_info entries. +func (h *btfExtHeader) funcInfoStart() int64 { + return int64(h.HdrLen + h.FuncInfoOff) +} + +// lineInfoStart returns the offset from the beginning of the .BTF.ext section +// to the start of its line_info entries. +func (h *btfExtHeader) lineInfoStart() int64 { + return int64(h.HdrLen + h.LineInfoOff) +} + +// coreReloStart returns the offset from the beginning of the .BTF.ext section +// to the start of its CO-RE relocation entries. +func (h *btfExtHeader) coreReloStart(ch *btfExtCOREHeader) int64 { + return int64(h.HdrLen + ch.COREReloOff) +} + +// btfExtCOREHeader is found right after the btfExtHeader when its HdrLen +// field is larger than its size. +type btfExtCOREHeader struct { + COREReloOff uint32 + COREReloLen uint32 +} + +// parseBTFExtCOREHeader parses the tail of the .BTF.ext header. If additional +// header bytes are present, extHeader.HdrLen will be larger than the struct, +// indicating the presence of a CO-RE extension header. +func parseBTFExtCOREHeader(r io.Reader, bo binary.ByteOrder, extHeader *btfExtHeader) (*btfExtCOREHeader, error) { + extHdrSize := int64(binary.Size(&extHeader)) + remainder := int64(extHeader.HdrLen) - extHdrSize + + if remainder == 0 { + return nil, nil + } + + var coreHeader btfExtCOREHeader + if err := binary.Read(r, bo, &coreHeader); err != nil { + return nil, fmt.Errorf("can't read header: %v", err) + } + + return &coreHeader, nil +} + +type btfExtInfoSec struct { + SecNameOff uint32 + NumInfo uint32 +} + +// parseExtInfoSec parses a btf_ext_info_sec header within .BTF.ext, +// appearing within func_info and line_info sub-sections. +// These headers appear once for each program section in the ELF and are +// followed by one or more func/line_info records for the section. +func parseExtInfoSec(r io.Reader, bo binary.ByteOrder, strings *stringTable) (string, *btfExtInfoSec, error) { + var infoHeader btfExtInfoSec + if err := binary.Read(r, bo, &infoHeader); err != nil { + return "", nil, fmt.Errorf("read ext info header: %w", err) + } + + secName, err := strings.Lookup(infoHeader.SecNameOff) + if err != nil { + return "", nil, fmt.Errorf("get section name: %w", err) + } + if secName == "" { + return "", nil, fmt.Errorf("extinfo header refers to empty section name") + } + + if infoHeader.NumInfo == 0 { + return "", nil, fmt.Errorf("section %s has zero records", secName) + } + + return secName, &infoHeader, nil +} + +// parseExtInfoRecordSize parses the uint32 at the beginning of a func_infos +// or line_infos segment that describes the length of all extInfoRecords in +// that segment. +func parseExtInfoRecordSize(r io.Reader, bo binary.ByteOrder) (uint32, error) { + const maxRecordSize = 256 + + var recordSize uint32 + if err := binary.Read(r, bo, &recordSize); err != nil { + return 0, fmt.Errorf("can't read record size: %v", err) + } + + if recordSize < 4 { + // Need at least InsnOff worth of bytes per record. + return 0, errors.New("record size too short") + } + if recordSize > maxRecordSize { + return 0, fmt.Errorf("record size %v exceeds %v", recordSize, maxRecordSize) + } + + return recordSize, nil +} + +// The size of a FuncInfo in BTF wire format. +var FuncInfoSize = uint32(binary.Size(bpfFuncInfo{})) + +type funcInfo struct { + fn *Func + offset asm.RawInstructionOffset +} + +type bpfFuncInfo struct { + // Instruction offset of the function within an ELF section. + InsnOff uint32 + TypeID TypeID +} + +func newFuncInfo(fi bpfFuncInfo, ts types) (*funcInfo, error) { + typ, err := ts.ByID(fi.TypeID) + if err != nil { + return nil, err + } + + fn, ok := typ.(*Func) + if !ok { + return nil, fmt.Errorf("type ID %d is a %T, but expected a Func", fi.TypeID, typ) + } + + // C doesn't have anonymous functions, but check just in case. + if fn.Name == "" { + return nil, fmt.Errorf("func with type ID %d doesn't have a name", fi.TypeID) + } + + return &funcInfo{ + fn, + asm.RawInstructionOffset(fi.InsnOff), + }, nil +} + +func newFuncInfos(bfis []bpfFuncInfo, ts types) ([]funcInfo, error) { + fis := make([]funcInfo, 0, len(bfis)) + for _, bfi := range bfis { + fi, err := newFuncInfo(bfi, ts) + if err != nil { + return nil, fmt.Errorf("offset %d: %w", bfi.InsnOff, err) + } + fis = append(fis, *fi) + } + sort.Slice(fis, func(i, j int) bool { + return fis[i].offset <= fis[j].offset + }) + return fis, nil +} + +// marshal into the BTF wire format. +func (fi *funcInfo) marshal(w io.Writer, typeID func(Type) (TypeID, error)) error { + id, err := typeID(fi.fn) + if err != nil { + return err + } + bfi := bpfFuncInfo{ + InsnOff: uint32(fi.offset), + TypeID: id, + } + return binary.Write(w, internal.NativeEndian, &bfi) +} + +// parseLineInfos parses a func_info sub-section within .BTF.ext ito a map of +// func infos indexed by section name. +func parseFuncInfos(r io.Reader, bo binary.ByteOrder, strings *stringTable) (map[string][]bpfFuncInfo, error) { + recordSize, err := parseExtInfoRecordSize(r, bo) + if err != nil { + return nil, err + } + + result := make(map[string][]bpfFuncInfo) + for { + secName, infoHeader, err := parseExtInfoSec(r, bo, strings) + if errors.Is(err, io.EOF) { + return result, nil + } + if err != nil { + return nil, err + } + + records, err := parseFuncInfoRecords(r, bo, recordSize, infoHeader.NumInfo) + if err != nil { + return nil, fmt.Errorf("section %v: %w", secName, err) + } + + result[secName] = records + } +} + +// parseFuncInfoRecords parses a stream of func_infos into a funcInfos. +// These records appear after a btf_ext_info_sec header in the func_info +// sub-section of .BTF.ext. +func parseFuncInfoRecords(r io.Reader, bo binary.ByteOrder, recordSize uint32, recordNum uint32) ([]bpfFuncInfo, error) { + var out []bpfFuncInfo + var fi bpfFuncInfo + + if exp, got := FuncInfoSize, recordSize; exp != got { + // BTF blob's record size is longer than we know how to parse. + return nil, fmt.Errorf("expected FuncInfo record size %d, but BTF blob contains %d", exp, got) + } + + for i := uint32(0); i < recordNum; i++ { + if err := binary.Read(r, bo, &fi); err != nil { + return nil, fmt.Errorf("can't read function info: %v", err) + } + + if fi.InsnOff%asm.InstructionSize != 0 { + return nil, fmt.Errorf("offset %v is not aligned with instruction size", fi.InsnOff) + } + + // ELF tracks offset in bytes, the kernel expects raw BPF instructions. + // Convert as early as possible. + fi.InsnOff /= asm.InstructionSize + + out = append(out, fi) + } + + return out, nil +} + +var LineInfoSize = uint32(binary.Size(bpfLineInfo{})) + +// Line represents the location and contents of a single line of source +// code a BPF ELF was compiled from. +type Line struct { + fileName string + line string + lineNumber uint32 + lineColumn uint32 + + // TODO: We should get rid of the fields below, but for that we need to be + // able to write BTF. + + fileNameOff uint32 + lineOff uint32 +} + +func (li *Line) FileName() string { + return li.fileName +} + +func (li *Line) Line() string { + return li.line +} + +func (li *Line) LineNumber() uint32 { + return li.lineNumber +} + +func (li *Line) LineColumn() uint32 { + return li.lineColumn +} + +func (li *Line) String() string { + return li.line +} + +type lineInfo struct { + line *Line + offset asm.RawInstructionOffset +} + +// Constants for the format of bpfLineInfo.LineCol. +const ( + bpfLineShift = 10 + bpfLineMax = (1 << (32 - bpfLineShift)) - 1 + bpfColumnMax = (1 << bpfLineShift) - 1 +) + +type bpfLineInfo struct { + // Instruction offset of the line within the whole instruction stream, in instructions. + InsnOff uint32 + FileNameOff uint32 + LineOff uint32 + LineCol uint32 +} + +func newLineInfo(li bpfLineInfo, strings *stringTable) (*lineInfo, error) { + line, err := strings.Lookup(li.LineOff) + if err != nil { + return nil, fmt.Errorf("lookup of line: %w", err) + } + + fileName, err := strings.Lookup(li.FileNameOff) + if err != nil { + return nil, fmt.Errorf("lookup of filename: %w", err) + } + + lineNumber := li.LineCol >> bpfLineShift + lineColumn := li.LineCol & bpfColumnMax + + return &lineInfo{ + &Line{ + fileName, + line, + lineNumber, + lineColumn, + li.FileNameOff, + li.LineOff, + }, + asm.RawInstructionOffset(li.InsnOff), + }, nil +} + +func newLineInfos(blis []bpfLineInfo, strings *stringTable) ([]lineInfo, error) { + lis := make([]lineInfo, 0, len(blis)) + for _, bli := range blis { + li, err := newLineInfo(bli, strings) + if err != nil { + return nil, fmt.Errorf("offset %d: %w", bli.InsnOff, err) + } + lis = append(lis, *li) + } + sort.Slice(lis, func(i, j int) bool { + return lis[i].offset <= lis[j].offset + }) + return lis, nil +} + +// marshal writes the binary representation of the LineInfo to w. +func (li *lineInfo) marshal(w io.Writer) error { + line := li.line + if line.lineNumber > bpfLineMax { + return fmt.Errorf("line %d exceeds %d", line.lineNumber, bpfLineMax) + } + + if line.lineColumn > bpfColumnMax { + return fmt.Errorf("column %d exceeds %d", line.lineColumn, bpfColumnMax) + } + + bli := bpfLineInfo{ + uint32(li.offset), + line.fileNameOff, + line.lineOff, + (line.lineNumber << bpfLineShift) | line.lineColumn, + } + return binary.Write(w, internal.NativeEndian, &bli) +} + +// parseLineInfos parses a line_info sub-section within .BTF.ext ito a map of +// line infos indexed by section name. +func parseLineInfos(r io.Reader, bo binary.ByteOrder, strings *stringTable) (map[string][]bpfLineInfo, error) { + recordSize, err := parseExtInfoRecordSize(r, bo) + if err != nil { + return nil, err + } + + result := make(map[string][]bpfLineInfo) + for { + secName, infoHeader, err := parseExtInfoSec(r, bo, strings) + if errors.Is(err, io.EOF) { + return result, nil + } + if err != nil { + return nil, err + } + + records, err := parseLineInfoRecords(r, bo, recordSize, infoHeader.NumInfo) + if err != nil { + return nil, fmt.Errorf("section %v: %w", secName, err) + } + + result[secName] = records + } +} + +// parseLineInfoRecords parses a stream of line_infos into a lineInfos. +// These records appear after a btf_ext_info_sec header in the line_info +// sub-section of .BTF.ext. +func parseLineInfoRecords(r io.Reader, bo binary.ByteOrder, recordSize uint32, recordNum uint32) ([]bpfLineInfo, error) { + var out []bpfLineInfo + var li bpfLineInfo + + if exp, got := uint32(binary.Size(li)), recordSize; exp != got { + // BTF blob's record size is longer than we know how to parse. + return nil, fmt.Errorf("expected LineInfo record size %d, but BTF blob contains %d", exp, got) + } + + for i := uint32(0); i < recordNum; i++ { + if err := binary.Read(r, bo, &li); err != nil { + return nil, fmt.Errorf("can't read line info: %v", err) + } + + if li.InsnOff%asm.InstructionSize != 0 { + return nil, fmt.Errorf("offset %v is not aligned with instruction size", li.InsnOff) + } + + // ELF tracks offset in bytes, the kernel expects raw BPF instructions. + // Convert as early as possible. + li.InsnOff /= asm.InstructionSize + + out = append(out, li) + } + + return out, nil +} + +// bpfCORERelo matches the kernel's struct bpf_core_relo. +type bpfCORERelo struct { + InsnOff uint32 + TypeID TypeID + AccessStrOff uint32 + Kind coreKind +} + +type CORERelocation struct { + typ Type + accessor coreAccessor + kind coreKind +} + +func CORERelocationMetadata(ins *asm.Instruction) *CORERelocation { + relo, _ := ins.Metadata.Get(coreRelocationMeta{}).(*CORERelocation) + return relo +} + +type coreRelocationInfo struct { + relo *CORERelocation + offset asm.RawInstructionOffset +} + +func newRelocationInfo(relo bpfCORERelo, ts types, strings *stringTable) (*coreRelocationInfo, error) { + typ, err := ts.ByID(relo.TypeID) + if err != nil { + return nil, err + } + + accessorStr, err := strings.Lookup(relo.AccessStrOff) + if err != nil { + return nil, err + } + + accessor, err := parseCOREAccessor(accessorStr) + if err != nil { + return nil, fmt.Errorf("accessor %q: %s", accessorStr, err) + } + + return &coreRelocationInfo{ + &CORERelocation{ + typ, + accessor, + relo.Kind, + }, + asm.RawInstructionOffset(relo.InsnOff), + }, nil +} + +func newRelocationInfos(brs []bpfCORERelo, ts types, strings *stringTable) ([]coreRelocationInfo, error) { + rs := make([]coreRelocationInfo, 0, len(brs)) + for _, br := range brs { + relo, err := newRelocationInfo(br, ts, strings) + if err != nil { + return nil, fmt.Errorf("offset %d: %w", br.InsnOff, err) + } + rs = append(rs, *relo) + } + sort.Slice(rs, func(i, j int) bool { + return rs[i].offset < rs[j].offset + }) + return rs, nil +} + +var extInfoReloSize = binary.Size(bpfCORERelo{}) + +// parseCORERelos parses a core_relos sub-section within .BTF.ext ito a map of +// CO-RE relocations indexed by section name. +func parseCORERelos(r io.Reader, bo binary.ByteOrder, strings *stringTable) (map[string][]bpfCORERelo, error) { + recordSize, err := parseExtInfoRecordSize(r, bo) + if err != nil { + return nil, err + } + + if recordSize != uint32(extInfoReloSize) { + return nil, fmt.Errorf("expected record size %d, got %d", extInfoReloSize, recordSize) + } + + result := make(map[string][]bpfCORERelo) + for { + secName, infoHeader, err := parseExtInfoSec(r, bo, strings) + if errors.Is(err, io.EOF) { + return result, nil + } + if err != nil { + return nil, err + } + + records, err := parseCOREReloRecords(r, bo, recordSize, infoHeader.NumInfo) + if err != nil { + return nil, fmt.Errorf("section %v: %w", secName, err) + } + + result[secName] = records + } +} + +// parseCOREReloRecords parses a stream of CO-RE relocation entries into a +// coreRelos. These records appear after a btf_ext_info_sec header in the +// core_relos sub-section of .BTF.ext. +func parseCOREReloRecords(r io.Reader, bo binary.ByteOrder, recordSize uint32, recordNum uint32) ([]bpfCORERelo, error) { + var out []bpfCORERelo + + var relo bpfCORERelo + for i := uint32(0); i < recordNum; i++ { + if err := binary.Read(r, bo, &relo); err != nil { + return nil, fmt.Errorf("can't read CO-RE relocation: %v", err) + } + + if relo.InsnOff%asm.InstructionSize != 0 { + return nil, fmt.Errorf("offset %v is not aligned with instruction size", relo.InsnOff) + } + + // ELF tracks offset in bytes, the kernel expects raw BPF instructions. + // Convert as early as possible. + relo.InsnOff /= asm.InstructionSize + + out = append(out, relo) + } + + return out, nil +} diff --git a/vendor/github.com/cilium/ebpf/btf/format.go b/vendor/github.com/cilium/ebpf/btf/format.go new file mode 100644 index 000000000..e7688a2a6 --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/format.go @@ -0,0 +1,319 @@ +package btf + +import ( + "errors" + "fmt" + "strings" +) + +var errNestedTooDeep = errors.New("nested too deep") + +// GoFormatter converts a Type to Go syntax. +// +// A zero GoFormatter is valid to use. +type GoFormatter struct { + w strings.Builder + + // Types present in this map are referred to using the given name if they + // are encountered when outputting another type. + Names map[Type]string + + // Identifier is called for each field of struct-like types. By default the + // field name is used as is. + Identifier func(string) string + + // EnumIdentifier is called for each element of an enum. By default the + // name of the enum type is concatenated with Identifier(element). + EnumIdentifier func(name, element string) string +} + +// TypeDeclaration generates a Go type declaration for a BTF type. +func (gf *GoFormatter) TypeDeclaration(name string, typ Type) (string, error) { + gf.w.Reset() + if err := gf.writeTypeDecl(name, typ); err != nil { + return "", err + } + return gf.w.String(), nil +} + +func (gf *GoFormatter) identifier(s string) string { + if gf.Identifier != nil { + return gf.Identifier(s) + } + + return s +} + +func (gf *GoFormatter) enumIdentifier(name, element string) string { + if gf.EnumIdentifier != nil { + return gf.EnumIdentifier(name, element) + } + + return name + gf.identifier(element) +} + +// writeTypeDecl outputs a declaration of the given type. +// +// It encodes https://golang.org/ref/spec#Type_declarations: +// +// type foo struct { bar uint32; } +// type bar int32 +func (gf *GoFormatter) writeTypeDecl(name string, typ Type) error { + if name == "" { + return fmt.Errorf("need a name for type %s", typ) + } + + switch v := skipQualifiers(typ).(type) { + case *Enum: + fmt.Fprintf(&gf.w, "type %s ", name) + switch v.Size { + case 1: + gf.w.WriteString("int8") + case 2: + gf.w.WriteString("int16") + case 4: + gf.w.WriteString("int32") + case 8: + gf.w.WriteString("int64") + default: + return fmt.Errorf("%s: invalid enum size %d", typ, v.Size) + } + + if len(v.Values) == 0 { + return nil + } + + gf.w.WriteString("; const ( ") + for _, ev := range v.Values { + id := gf.enumIdentifier(name, ev.Name) + fmt.Fprintf(&gf.w, "%s %s = %d; ", id, name, ev.Value) + } + gf.w.WriteString(")") + + return nil + + default: + fmt.Fprintf(&gf.w, "type %s ", name) + return gf.writeTypeLit(v, 0) + } +} + +// writeType outputs the name of a named type or a literal describing the type. +// +// It encodes https://golang.org/ref/spec#Types. +// +// foo (if foo is a named type) +// uint32 +func (gf *GoFormatter) writeType(typ Type, depth int) error { + typ = skipQualifiers(typ) + + name := gf.Names[typ] + if name != "" { + gf.w.WriteString(name) + return nil + } + + return gf.writeTypeLit(typ, depth) +} + +// writeTypeLit outputs a literal describing the type. +// +// The function ignores named types. +// +// It encodes https://golang.org/ref/spec#TypeLit. +// +// struct { bar uint32; } +// uint32 +func (gf *GoFormatter) writeTypeLit(typ Type, depth int) error { + depth++ + if depth > maxTypeDepth { + return errNestedTooDeep + } + + var err error + switch v := skipQualifiers(typ).(type) { + case *Int: + gf.writeIntLit(v) + + case *Enum: + gf.w.WriteString("int32") + + case *Typedef: + err = gf.writeType(v.Type, depth) + + case *Array: + fmt.Fprintf(&gf.w, "[%d]", v.Nelems) + err = gf.writeType(v.Type, depth) + + case *Struct: + err = gf.writeStructLit(v.Size, v.Members, depth) + + case *Union: + // Always choose the first member to represent the union in Go. + err = gf.writeStructLit(v.Size, v.Members[:1], depth) + + case *Datasec: + err = gf.writeDatasecLit(v, depth) + + default: + return fmt.Errorf("type %T: %w", v, ErrNotSupported) + } + + if err != nil { + return fmt.Errorf("%s: %w", typ, err) + } + + return nil +} + +func (gf *GoFormatter) writeIntLit(i *Int) { + // NB: Encoding.IsChar is ignored. + if i.Encoding.IsBool() && i.Size == 1 { + gf.w.WriteString("bool") + return + } + + bits := i.Size * 8 + if i.Encoding.IsSigned() { + fmt.Fprintf(&gf.w, "int%d", bits) + } else { + fmt.Fprintf(&gf.w, "uint%d", bits) + } +} + +func (gf *GoFormatter) writeStructLit(size uint32, members []Member, depth int) error { + gf.w.WriteString("struct { ") + + prevOffset := uint32(0) + skippedBitfield := false + for i, m := range members { + if m.BitfieldSize > 0 { + skippedBitfield = true + continue + } + + offset := m.Offset.Bytes() + if n := offset - prevOffset; skippedBitfield && n > 0 { + fmt.Fprintf(&gf.w, "_ [%d]byte /* unsupported bitfield */; ", n) + } else { + gf.writePadding(n) + } + + size, err := Sizeof(m.Type) + if err != nil { + return fmt.Errorf("field %d: %w", i, err) + } + prevOffset = offset + uint32(size) + + if err := gf.writeStructField(m, depth); err != nil { + return fmt.Errorf("field %d: %w", i, err) + } + } + + gf.writePadding(size - prevOffset) + gf.w.WriteString("}") + return nil +} + +func (gf *GoFormatter) writeStructField(m Member, depth int) error { + if m.BitfieldSize > 0 { + return fmt.Errorf("bitfields are not supported") + } + if m.Offset%8 != 0 { + return fmt.Errorf("unsupported offset %d", m.Offset) + } + + if m.Name == "" { + // Special case a nested anonymous union like + // struct foo { union { int bar; int baz }; } + // by replacing the whole union with its first member. + union, ok := m.Type.(*Union) + if !ok { + return fmt.Errorf("anonymous fields are not supported") + + } + + if len(union.Members) == 0 { + return errors.New("empty anonymous union") + } + + depth++ + if depth > maxTypeDepth { + return errNestedTooDeep + } + + m := union.Members[0] + size, err := Sizeof(m.Type) + if err != nil { + return err + } + + if err := gf.writeStructField(m, depth); err != nil { + return err + } + + gf.writePadding(union.Size - uint32(size)) + return nil + + } + + fmt.Fprintf(&gf.w, "%s ", gf.identifier(m.Name)) + + if err := gf.writeType(m.Type, depth); err != nil { + return err + } + + gf.w.WriteString("; ") + return nil +} + +func (gf *GoFormatter) writeDatasecLit(ds *Datasec, depth int) error { + gf.w.WriteString("struct { ") + + prevOffset := uint32(0) + for i, vsi := range ds.Vars { + v := vsi.Type.(*Var) + if v.Linkage != GlobalVar { + // Ignore static, extern, etc. for now. + continue + } + + if v.Name == "" { + return fmt.Errorf("variable %d: empty name", i) + } + + gf.writePadding(vsi.Offset - prevOffset) + prevOffset = vsi.Offset + vsi.Size + + fmt.Fprintf(&gf.w, "%s ", gf.identifier(v.Name)) + + if err := gf.writeType(v.Type, depth); err != nil { + return fmt.Errorf("variable %d: %w", i, err) + } + + gf.w.WriteString("; ") + } + + gf.writePadding(ds.Size - prevOffset) + gf.w.WriteString("}") + return nil +} + +func (gf *GoFormatter) writePadding(bytes uint32) { + if bytes > 0 { + fmt.Fprintf(&gf.w, "_ [%d]byte; ", bytes) + } +} + +func skipQualifiers(typ Type) Type { + result := typ + for depth := 0; depth <= maxTypeDepth; depth++ { + switch v := (result).(type) { + case qualifier: + result = v.qualify() + default: + return result + } + } + return &cycle{typ} +} diff --git a/vendor/github.com/cilium/ebpf/btf/handle.go b/vendor/github.com/cilium/ebpf/btf/handle.go new file mode 100644 index 000000000..128e9b35c --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/handle.go @@ -0,0 +1,121 @@ +package btf + +import ( + "errors" + "fmt" + "os" + + "github.com/cilium/ebpf/internal/sys" + "github.com/cilium/ebpf/internal/unix" +) + +// HandleInfo describes a Handle. +type HandleInfo struct { + // ID of this handle in the kernel. The ID is only valid as long as the + // associated handle is kept alive. + ID ID + + // Name is an identifying name for the BTF, currently only used by the + // kernel. + Name string + + // IsKernel is true if the BTF originated with the kernel and not + // userspace. + IsKernel bool + + // Size of the raw BTF in bytes. + size uint32 +} + +func newHandleInfoFromFD(fd *sys.FD) (*HandleInfo, error) { + // We invoke the syscall once with a empty BTF and name buffers to get size + // information to allocate buffers. Then we invoke it a second time with + // buffers to receive the data. + var btfInfo sys.BtfInfo + if err := sys.ObjInfo(fd, &btfInfo); err != nil { + return nil, fmt.Errorf("get BTF info for fd %s: %w", fd, err) + } + + if btfInfo.NameLen > 0 { + // NameLen doesn't account for the terminating NUL. + btfInfo.NameLen++ + } + + // Don't pull raw BTF by default, since it may be quite large. + btfSize := btfInfo.BtfSize + btfInfo.BtfSize = 0 + + nameBuffer := make([]byte, btfInfo.NameLen) + btfInfo.Name, btfInfo.NameLen = sys.NewSlicePointerLen(nameBuffer) + if err := sys.ObjInfo(fd, &btfInfo); err != nil { + return nil, err + } + + return &HandleInfo{ + ID: ID(btfInfo.Id), + Name: unix.ByteSliceToString(nameBuffer), + IsKernel: btfInfo.KernelBtf != 0, + size: btfSize, + }, nil +} + +// IsModule returns true if the BTF is for the kernel itself. +func (i *HandleInfo) IsVmlinux() bool { + return i.IsKernel && i.Name == "vmlinux" +} + +// IsModule returns true if the BTF is for a kernel module. +func (i *HandleInfo) IsModule() bool { + return i.IsKernel && i.Name != "vmlinux" +} + +// HandleIterator allows enumerating BTF blobs loaded into the kernel. +type HandleIterator struct { + // The ID of the last retrieved handle. Only valid after a call to Next. + ID ID + err error +} + +// Next retrieves a handle for the next BTF blob. +// +// [Handle.Close] is called if *handle is non-nil to avoid leaking fds. +// +// Returns true if another BTF blob was found. Call [HandleIterator.Err] after +// the function returns false. +func (it *HandleIterator) Next(handle **Handle) bool { + if *handle != nil { + (*handle).Close() + *handle = nil + } + + id := it.ID + for { + attr := &sys.BtfGetNextIdAttr{Id: id} + err := sys.BtfGetNextId(attr) + if errors.Is(err, os.ErrNotExist) { + // There are no more BTF objects. + return false + } else if err != nil { + it.err = fmt.Errorf("get next BTF ID: %w", err) + return false + } + + id = attr.NextId + *handle, err = NewHandleFromID(id) + if errors.Is(err, os.ErrNotExist) { + // Try again with the next ID. + continue + } else if err != nil { + it.err = fmt.Errorf("retrieve handle for ID %d: %w", id, err) + return false + } + + it.ID = id + return true + } +} + +// Err returns an error if iteration failed for some reason. +func (it *HandleIterator) Err() error { + return it.err +} diff --git a/vendor/github.com/cilium/ebpf/btf/strings.go b/vendor/github.com/cilium/ebpf/btf/strings.go new file mode 100644 index 000000000..67626e0dd --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/strings.go @@ -0,0 +1,128 @@ +package btf + +import ( + "bufio" + "bytes" + "errors" + "fmt" + "io" +) + +type stringTable struct { + base *stringTable + offsets []uint32 + strings []string +} + +// sizedReader is implemented by bytes.Reader, io.SectionReader, strings.Reader, etc. +type sizedReader interface { + io.Reader + Size() int64 +} + +func readStringTable(r sizedReader, base *stringTable) (*stringTable, error) { + // When parsing split BTF's string table, the first entry offset is derived + // from the last entry offset of the base BTF. + firstStringOffset := uint32(0) + if base != nil { + idx := len(base.offsets) - 1 + firstStringOffset = base.offsets[idx] + uint32(len(base.strings[idx])) + 1 + } + + // Derived from vmlinux BTF. + const averageStringLength = 16 + + n := int(r.Size() / averageStringLength) + offsets := make([]uint32, 0, n) + strings := make([]string, 0, n) + + offset := firstStringOffset + scanner := bufio.NewScanner(r) + scanner.Split(splitNull) + for scanner.Scan() { + str := scanner.Text() + offsets = append(offsets, offset) + strings = append(strings, str) + offset += uint32(len(str)) + 1 + } + if err := scanner.Err(); err != nil { + return nil, err + } + + if len(strings) == 0 { + return nil, errors.New("string table is empty") + } + + if firstStringOffset == 0 && strings[0] != "" { + return nil, errors.New("first item in string table is non-empty") + } + + return &stringTable{base, offsets, strings}, nil +} + +func splitNull(data []byte, atEOF bool) (advance int, token []byte, err error) { + i := bytes.IndexByte(data, 0) + if i == -1 { + if atEOF && len(data) > 0 { + return 0, nil, errors.New("string table isn't null terminated") + } + return 0, nil, nil + } + + return i + 1, data[:i], nil +} + +func (st *stringTable) Lookup(offset uint32) (string, error) { + if st.base != nil && offset <= st.base.offsets[len(st.base.offsets)-1] { + return st.base.lookup(offset) + } + return st.lookup(offset) +} + +func (st *stringTable) lookup(offset uint32) (string, error) { + i := search(st.offsets, offset) + if i == len(st.offsets) || st.offsets[i] != offset { + return "", fmt.Errorf("offset %d isn't start of a string", offset) + } + + return st.strings[i], nil +} + +func (st *stringTable) Length() int { + last := len(st.offsets) - 1 + return int(st.offsets[last]) + len(st.strings[last]) + 1 +} + +func (st *stringTable) Marshal(w io.Writer) error { + for _, str := range st.strings { + _, err := io.WriteString(w, str) + if err != nil { + return err + } + _, err = w.Write([]byte{0}) + if err != nil { + return err + } + } + return nil +} + +// search is a copy of sort.Search specialised for uint32. +// +// Licensed under https://go.dev/LICENSE +func search(ints []uint32, needle uint32) int { + // Define f(-1) == false and f(n) == true. + // Invariant: f(i-1) == false, f(j) == true. + i, j := 0, len(ints) + for i < j { + h := int(uint(i+j) >> 1) // avoid overflow when computing h + // i ≤ h < j + if !(ints[h] >= needle) { + i = h + 1 // preserves f(i-1) == false + } else { + j = h // preserves f(j) == true + } + } + // i == j, f(i-1) == false, and f(j) (= f(i)) == true => answer is i. + return i +} diff --git a/vendor/github.com/cilium/ebpf/btf/types.go b/vendor/github.com/cilium/ebpf/btf/types.go new file mode 100644 index 000000000..402a363c2 --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/types.go @@ -0,0 +1,1212 @@ +package btf + +import ( + "fmt" + "io" + "math" + "reflect" + "strings" + + "github.com/cilium/ebpf/asm" +) + +const maxTypeDepth = 32 + +// TypeID identifies a type in a BTF section. +type TypeID uint32 + +// Type represents a type described by BTF. +type Type interface { + // Type can be formatted using the %s and %v verbs. %s outputs only the + // identity of the type, without any detail. %v outputs additional detail. + // + // Use the '+' flag to include the address of the type. + // + // Use the width to specify how many levels of detail to output, for example + // %1v will output detail for the root type and a short description of its + // children. %2v would output details of the root type and its children + // as well as a short description of the grandchildren. + fmt.Formatter + + // Name of the type, empty for anonymous types and types that cannot + // carry a name, like Void and Pointer. + TypeName() string + + // Make a copy of the type, without copying Type members. + copy() Type + + // Enumerate all nested Types. Repeated calls must visit nested + // types in the same order. + walk(*typeDeque) +} + +var ( + _ Type = (*Int)(nil) + _ Type = (*Struct)(nil) + _ Type = (*Union)(nil) + _ Type = (*Enum)(nil) + _ Type = (*Fwd)(nil) + _ Type = (*Func)(nil) + _ Type = (*Typedef)(nil) + _ Type = (*Var)(nil) + _ Type = (*Datasec)(nil) + _ Type = (*Float)(nil) +) + +// types is a list of Type. +// +// The order determines the ID of a type. +type types []Type + +func (ts types) ByID(id TypeID) (Type, error) { + if int(id) > len(ts) { + return nil, fmt.Errorf("type ID %d: %w", id, ErrNotFound) + } + return ts[id], nil +} + +// Void is the unit type of BTF. +type Void struct{} + +func (v *Void) Format(fs fmt.State, verb rune) { formatType(fs, verb, v) } +func (v *Void) TypeName() string { return "" } +func (v *Void) size() uint32 { return 0 } +func (v *Void) copy() Type { return (*Void)(nil) } +func (v *Void) walk(*typeDeque) {} + +type IntEncoding byte + +const ( + Signed IntEncoding = 1 << iota + Char + Bool +) + +func (ie IntEncoding) IsSigned() bool { + return ie&Signed != 0 +} + +func (ie IntEncoding) IsChar() bool { + return ie&Char != 0 +} + +func (ie IntEncoding) IsBool() bool { + return ie&Bool != 0 +} + +func (ie IntEncoding) String() string { + switch { + case ie.IsChar() && ie.IsSigned(): + return "char" + case ie.IsChar() && !ie.IsSigned(): + return "uchar" + case ie.IsBool(): + return "bool" + case ie.IsSigned(): + return "signed" + default: + return "unsigned" + } +} + +// Int is an integer of a given length. +// +// See https://www.kernel.org/doc/html/latest/bpf/btf.html#btf-kind-int +type Int struct { + Name string + + // The size of the integer in bytes. + Size uint32 + Encoding IntEncoding +} + +func (i *Int) Format(fs fmt.State, verb rune) { + formatType(fs, verb, i, i.Encoding, "size=", i.Size*8) +} + +func (i *Int) TypeName() string { return i.Name } +func (i *Int) size() uint32 { return i.Size } +func (i *Int) walk(*typeDeque) {} +func (i *Int) copy() Type { + cpy := *i + return &cpy +} + +// Pointer is a pointer to another type. +type Pointer struct { + Target Type +} + +func (p *Pointer) Format(fs fmt.State, verb rune) { + formatType(fs, verb, p, "target=", p.Target) +} + +func (p *Pointer) TypeName() string { return "" } +func (p *Pointer) size() uint32 { return 8 } +func (p *Pointer) walk(tdq *typeDeque) { tdq.push(&p.Target) } +func (p *Pointer) copy() Type { + cpy := *p + return &cpy +} + +// Array is an array with a fixed number of elements. +type Array struct { + Index Type + Type Type + Nelems uint32 +} + +func (arr *Array) Format(fs fmt.State, verb rune) { + formatType(fs, verb, arr, "index=", arr.Index, "type=", arr.Type, "n=", arr.Nelems) +} + +func (arr *Array) TypeName() string { return "" } + +func (arr *Array) walk(tdq *typeDeque) { + tdq.push(&arr.Index) + tdq.push(&arr.Type) +} + +func (arr *Array) copy() Type { + cpy := *arr + return &cpy +} + +// Struct is a compound type of consecutive members. +type Struct struct { + Name string + // The size of the struct including padding, in bytes + Size uint32 + Members []Member +} + +func (s *Struct) Format(fs fmt.State, verb rune) { + formatType(fs, verb, s, "fields=", len(s.Members)) +} + +func (s *Struct) TypeName() string { return s.Name } + +func (s *Struct) size() uint32 { return s.Size } + +func (s *Struct) walk(tdq *typeDeque) { + for i := range s.Members { + tdq.push(&s.Members[i].Type) + } +} + +func (s *Struct) copy() Type { + cpy := *s + cpy.Members = copyMembers(s.Members) + return &cpy +} + +func (s *Struct) members() []Member { + return s.Members +} + +// Union is a compound type where members occupy the same memory. +type Union struct { + Name string + // The size of the union including padding, in bytes. + Size uint32 + Members []Member +} + +func (u *Union) Format(fs fmt.State, verb rune) { + formatType(fs, verb, u, "fields=", len(u.Members)) +} + +func (u *Union) TypeName() string { return u.Name } + +func (u *Union) size() uint32 { return u.Size } + +func (u *Union) walk(tdq *typeDeque) { + for i := range u.Members { + tdq.push(&u.Members[i].Type) + } +} + +func (u *Union) copy() Type { + cpy := *u + cpy.Members = copyMembers(u.Members) + return &cpy +} + +func (u *Union) members() []Member { + return u.Members +} + +func copyMembers(orig []Member) []Member { + cpy := make([]Member, len(orig)) + copy(cpy, orig) + return cpy +} + +type composite interface { + members() []Member +} + +var ( + _ composite = (*Struct)(nil) + _ composite = (*Union)(nil) +) + +// A value in bits. +type Bits uint32 + +// Bytes converts a bit value into bytes. +func (b Bits) Bytes() uint32 { + return uint32(b / 8) +} + +// Member is part of a Struct or Union. +// +// It is not a valid Type. +type Member struct { + Name string + Type Type + Offset Bits + BitfieldSize Bits +} + +// Enum lists possible values. +type Enum struct { + Name string + // Size of the enum value in bytes. + Size uint32 + Values []EnumValue +} + +func (e *Enum) Format(fs fmt.State, verb rune) { + formatType(fs, verb, e, "size=", e.Size, "values=", len(e.Values)) +} + +func (e *Enum) TypeName() string { return e.Name } + +// EnumValue is part of an Enum +// +// Is is not a valid Type +type EnumValue struct { + Name string + Value int32 +} + +func (e *Enum) size() uint32 { return e.Size } +func (e *Enum) walk(*typeDeque) {} +func (e *Enum) copy() Type { + cpy := *e + cpy.Values = make([]EnumValue, len(e.Values)) + copy(cpy.Values, e.Values) + return &cpy +} + +// FwdKind is the type of forward declaration. +type FwdKind int + +// Valid types of forward declaration. +const ( + FwdStruct FwdKind = iota + FwdUnion +) + +func (fk FwdKind) String() string { + switch fk { + case FwdStruct: + return "struct" + case FwdUnion: + return "union" + default: + return fmt.Sprintf("%T(%d)", fk, int(fk)) + } +} + +// Fwd is a forward declaration of a Type. +type Fwd struct { + Name string + Kind FwdKind +} + +func (f *Fwd) Format(fs fmt.State, verb rune) { + formatType(fs, verb, f, f.Kind) +} + +func (f *Fwd) TypeName() string { return f.Name } + +func (f *Fwd) walk(*typeDeque) {} +func (f *Fwd) copy() Type { + cpy := *f + return &cpy +} + +// Typedef is an alias of a Type. +type Typedef struct { + Name string + Type Type +} + +func (td *Typedef) Format(fs fmt.State, verb rune) { + formatType(fs, verb, td, td.Type) +} + +func (td *Typedef) TypeName() string { return td.Name } + +func (td *Typedef) walk(tdq *typeDeque) { tdq.push(&td.Type) } +func (td *Typedef) copy() Type { + cpy := *td + return &cpy +} + +// Volatile is a qualifier. +type Volatile struct { + Type Type +} + +func (v *Volatile) Format(fs fmt.State, verb rune) { + formatType(fs, verb, v, v.Type) +} + +func (v *Volatile) TypeName() string { return "" } + +func (v *Volatile) qualify() Type { return v.Type } +func (v *Volatile) walk(tdq *typeDeque) { tdq.push(&v.Type) } +func (v *Volatile) copy() Type { + cpy := *v + return &cpy +} + +// Const is a qualifier. +type Const struct { + Type Type +} + +func (c *Const) Format(fs fmt.State, verb rune) { + formatType(fs, verb, c, c.Type) +} + +func (c *Const) TypeName() string { return "" } + +func (c *Const) qualify() Type { return c.Type } +func (c *Const) walk(tdq *typeDeque) { tdq.push(&c.Type) } +func (c *Const) copy() Type { + cpy := *c + return &cpy +} + +// Restrict is a qualifier. +type Restrict struct { + Type Type +} + +func (r *Restrict) Format(fs fmt.State, verb rune) { + formatType(fs, verb, r, r.Type) +} + +func (r *Restrict) TypeName() string { return "" } + +func (r *Restrict) qualify() Type { return r.Type } +func (r *Restrict) walk(tdq *typeDeque) { tdq.push(&r.Type) } +func (r *Restrict) copy() Type { + cpy := *r + return &cpy +} + +// Func is a function definition. +type Func struct { + Name string + Type Type + Linkage FuncLinkage +} + +func FuncMetadata(ins *asm.Instruction) *Func { + fn, _ := ins.Metadata.Get(funcInfoMeta{}).(*Func) + return fn +} + +func (f *Func) Format(fs fmt.State, verb rune) { + formatType(fs, verb, f, f.Linkage, "proto=", f.Type) +} + +func (f *Func) TypeName() string { return f.Name } + +func (f *Func) walk(tdq *typeDeque) { tdq.push(&f.Type) } +func (f *Func) copy() Type { + cpy := *f + return &cpy +} + +// FuncProto is a function declaration. +type FuncProto struct { + Return Type + Params []FuncParam +} + +func (fp *FuncProto) Format(fs fmt.State, verb rune) { + formatType(fs, verb, fp, "args=", len(fp.Params), "return=", fp.Return) +} + +func (fp *FuncProto) TypeName() string { return "" } + +func (fp *FuncProto) walk(tdq *typeDeque) { + tdq.push(&fp.Return) + for i := range fp.Params { + tdq.push(&fp.Params[i].Type) + } +} + +func (fp *FuncProto) copy() Type { + cpy := *fp + cpy.Params = make([]FuncParam, len(fp.Params)) + copy(cpy.Params, fp.Params) + return &cpy +} + +type FuncParam struct { + Name string + Type Type +} + +// Var is a global variable. +type Var struct { + Name string + Type Type + Linkage VarLinkage +} + +func (v *Var) Format(fs fmt.State, verb rune) { + formatType(fs, verb, v, v.Linkage) +} + +func (v *Var) TypeName() string { return v.Name } + +func (v *Var) walk(tdq *typeDeque) { tdq.push(&v.Type) } +func (v *Var) copy() Type { + cpy := *v + return &cpy +} + +// Datasec is a global program section containing data. +type Datasec struct { + Name string + Size uint32 + Vars []VarSecinfo +} + +func (ds *Datasec) Format(fs fmt.State, verb rune) { + formatType(fs, verb, ds) +} + +func (ds *Datasec) TypeName() string { return ds.Name } + +func (ds *Datasec) size() uint32 { return ds.Size } + +func (ds *Datasec) walk(tdq *typeDeque) { + for i := range ds.Vars { + tdq.push(&ds.Vars[i].Type) + } +} + +func (ds *Datasec) copy() Type { + cpy := *ds + cpy.Vars = make([]VarSecinfo, len(ds.Vars)) + copy(cpy.Vars, ds.Vars) + return &cpy +} + +// VarSecinfo describes variable in a Datasec. +// +// It is not a valid Type. +type VarSecinfo struct { + Type Type + Offset uint32 + Size uint32 +} + +// Float is a float of a given length. +type Float struct { + Name string + + // The size of the float in bytes. + Size uint32 +} + +func (f *Float) Format(fs fmt.State, verb rune) { + formatType(fs, verb, f, "size=", f.Size*8) +} + +func (f *Float) TypeName() string { return f.Name } +func (f *Float) size() uint32 { return f.Size } +func (f *Float) walk(*typeDeque) {} +func (f *Float) copy() Type { + cpy := *f + return &cpy +} + +// cycle is a type which had to be elided since it exceeded maxTypeDepth. +type cycle struct { + root Type +} + +func (c *cycle) ID() TypeID { return math.MaxUint32 } +func (c *cycle) Format(fs fmt.State, verb rune) { formatType(fs, verb, c, "root=", c.root) } +func (c *cycle) TypeName() string { return "" } +func (c *cycle) walk(*typeDeque) {} +func (c *cycle) copy() Type { + cpy := *c + return &cpy +} + +type sizer interface { + size() uint32 +} + +var ( + _ sizer = (*Int)(nil) + _ sizer = (*Pointer)(nil) + _ sizer = (*Struct)(nil) + _ sizer = (*Union)(nil) + _ sizer = (*Enum)(nil) + _ sizer = (*Datasec)(nil) +) + +type qualifier interface { + qualify() Type +} + +var ( + _ qualifier = (*Const)(nil) + _ qualifier = (*Restrict)(nil) + _ qualifier = (*Volatile)(nil) +) + +// Sizeof returns the size of a type in bytes. +// +// Returns an error if the size can't be computed. +func Sizeof(typ Type) (int, error) { + var ( + n = int64(1) + elem int64 + ) + + for i := 0; i < maxTypeDepth; i++ { + switch v := typ.(type) { + case *Array: + if n > 0 && int64(v.Nelems) > math.MaxInt64/n { + return 0, fmt.Errorf("type %s: overflow", typ) + } + + // Arrays may be of zero length, which allows + // n to be zero as well. + n *= int64(v.Nelems) + typ = v.Type + continue + + case sizer: + elem = int64(v.size()) + + case *Typedef: + typ = v.Type + continue + + case qualifier: + typ = v.qualify() + continue + + default: + return 0, fmt.Errorf("unsized type %T", typ) + } + + if n > 0 && elem > math.MaxInt64/n { + return 0, fmt.Errorf("type %s: overflow", typ) + } + + size := n * elem + if int64(int(size)) != size { + return 0, fmt.Errorf("type %s: overflow", typ) + } + + return int(size), nil + } + + return 0, fmt.Errorf("type %s: exceeded type depth", typ) +} + +// alignof returns the alignment of a type. +// +// Currently only supports the subset of types necessary for bitfield relocations. +func alignof(typ Type) (int, error) { + switch t := UnderlyingType(typ).(type) { + case *Enum: + return int(t.size()), nil + case *Int: + return int(t.Size), nil + default: + return 0, fmt.Errorf("can't calculate alignment of %T", t) + } +} + +// Transformer modifies a given Type and returns the result. +// +// For example, UnderlyingType removes any qualifiers or typedefs from a type. +// See the example on Copy for how to use a transform. +type Transformer func(Type) Type + +// Copy a Type recursively. +// +// typ may form a cycle. If transform is not nil, it is called with the +// to be copied type, and the returned value is copied instead. +func Copy(typ Type, transform Transformer) Type { + copies := make(copier) + copies.copy(&typ, transform) + return typ +} + +// copy a slice of Types recursively. +// +// See Copy for the semantics. +func copyTypes(types []Type, transform Transformer) []Type { + result := make([]Type, len(types)) + copy(result, types) + + copies := make(copier) + for i := range result { + copies.copy(&result[i], transform) + } + + return result +} + +type copier map[Type]Type + +func (c copier) copy(typ *Type, transform Transformer) { + var work typeDeque + for t := typ; t != nil; t = work.pop() { + // *t is the identity of the type. + if cpy := c[*t]; cpy != nil { + *t = cpy + continue + } + + var cpy Type + if transform != nil { + cpy = transform(*t).copy() + } else { + cpy = (*t).copy() + } + + c[*t] = cpy + *t = cpy + + // Mark any nested types for copying. + cpy.walk(&work) + } +} + +// typeDeque keeps track of pointers to types which still +// need to be visited. +type typeDeque struct { + types []*Type + read, write uint64 + mask uint64 +} + +func (dq *typeDeque) empty() bool { + return dq.read == dq.write +} + +// push adds a type to the stack. +func (dq *typeDeque) push(t *Type) { + if dq.write-dq.read < uint64(len(dq.types)) { + dq.types[dq.write&dq.mask] = t + dq.write++ + return + } + + new := len(dq.types) * 2 + if new == 0 { + new = 8 + } + + types := make([]*Type, new) + pivot := dq.read & dq.mask + n := copy(types, dq.types[pivot:]) + n += copy(types[n:], dq.types[:pivot]) + types[n] = t + + dq.types = types + dq.mask = uint64(new) - 1 + dq.read, dq.write = 0, uint64(n+1) +} + +// shift returns the first element or null. +func (dq *typeDeque) shift() *Type { + if dq.empty() { + return nil + } + + index := dq.read & dq.mask + t := dq.types[index] + dq.types[index] = nil + dq.read++ + return t +} + +// pop returns the last element or null. +func (dq *typeDeque) pop() *Type { + if dq.empty() { + return nil + } + + dq.write-- + index := dq.write & dq.mask + t := dq.types[index] + dq.types[index] = nil + return t +} + +// all returns all elements. +// +// The deque is empty after calling this method. +func (dq *typeDeque) all() []*Type { + length := dq.write - dq.read + types := make([]*Type, 0, length) + for t := dq.shift(); t != nil; t = dq.shift() { + types = append(types, t) + } + return types +} + +// inflateRawTypes takes a list of raw btf types linked via type IDs, and turns +// it into a graph of Types connected via pointers. +// +// If baseTypes are provided, then the raw types are +// considered to be of a split BTF (e.g., a kernel module). +// +// Returns a slice of types indexed by TypeID. Since BTF ignores compilation +// units, multiple types may share the same name. A Type may form a cyclic graph +// by pointing at itself. +func inflateRawTypes(rawTypes []rawType, baseTypes types, rawStrings *stringTable) ([]Type, error) { + types := make([]Type, 0, len(rawTypes)+1) // +1 for Void added to base types + + typeIDOffset := TypeID(1) // Void is TypeID(0), so the rest starts from TypeID(1) + + if baseTypes == nil { + // Void is defined to always be type ID 0, and is thus omitted from BTF. + types = append(types, (*Void)(nil)) + } else { + // For split BTF, the next ID is max base BTF type ID + 1 + typeIDOffset = TypeID(len(baseTypes)) + } + + type fixupDef struct { + id TypeID + typ *Type + } + + var fixups []fixupDef + fixup := func(id TypeID, typ *Type) { + if id < TypeID(len(baseTypes)) { + *typ = baseTypes[id] + return + } + + idx := id + if baseTypes != nil { + idx = id - TypeID(len(baseTypes)) + } + if idx < TypeID(len(types)) { + // We've already inflated this type, fix it up immediately. + *typ = types[idx] + return + } + fixups = append(fixups, fixupDef{id, typ}) + } + + type assertion struct { + typ *Type + want reflect.Type + } + + var assertions []assertion + assert := func(typ *Type, want reflect.Type) error { + if *typ != nil { + // The type has already been fixed up, check the type immediately. + if reflect.TypeOf(*typ) != want { + return fmt.Errorf("expected %s, got %T", want, *typ) + } + return nil + } + assertions = append(assertions, assertion{typ, want}) + return nil + } + + type bitfieldFixupDef struct { + id TypeID + m *Member + } + + var ( + legacyBitfields = make(map[TypeID][2]Bits) // offset, size + bitfieldFixups []bitfieldFixupDef + ) + convertMembers := func(raw []btfMember, kindFlag bool) ([]Member, error) { + // NB: The fixup below relies on pre-allocating this array to + // work, since otherwise append might re-allocate members. + members := make([]Member, 0, len(raw)) + for i, btfMember := range raw { + name, err := rawStrings.Lookup(btfMember.NameOff) + if err != nil { + return nil, fmt.Errorf("can't get name for member %d: %w", i, err) + } + + members = append(members, Member{ + Name: name, + Offset: Bits(btfMember.Offset), + }) + + m := &members[i] + fixup(raw[i].Type, &m.Type) + + if kindFlag { + m.BitfieldSize = Bits(btfMember.Offset >> 24) + m.Offset &= 0xffffff + // We ignore legacy bitfield definitions if the current composite + // is a new-style bitfield. This is kind of safe since offset and + // size on the type of the member must be zero if kindFlat is set + // according to spec. + continue + } + + // This may be a legacy bitfield, try to fix it up. + data, ok := legacyBitfields[raw[i].Type] + if ok { + // Bingo! + m.Offset += data[0] + m.BitfieldSize = data[1] + continue + } + + if m.Type != nil { + // We couldn't find a legacy bitfield, but we know that the member's + // type has already been inflated. Hence we know that it can't be + // a legacy bitfield and there is nothing left to do. + continue + } + + // We don't have fixup data, and the type we're pointing + // at hasn't been inflated yet. No choice but to defer + // the fixup. + bitfieldFixups = append(bitfieldFixups, bitfieldFixupDef{ + raw[i].Type, + m, + }) + } + return members, nil + } + + for i, raw := range rawTypes { + var ( + id = typeIDOffset + TypeID(i) + typ Type + ) + + name, err := rawStrings.Lookup(raw.NameOff) + if err != nil { + return nil, fmt.Errorf("get name for type id %d: %w", id, err) + } + + switch raw.Kind() { + case kindInt: + size := raw.Size() + bi := raw.data.(*btfInt) + if bi.Offset() > 0 || bi.Bits().Bytes() != size { + legacyBitfields[id] = [2]Bits{bi.Offset(), bi.Bits()} + } + typ = &Int{name, raw.Size(), bi.Encoding()} + + case kindPointer: + ptr := &Pointer{nil} + fixup(raw.Type(), &ptr.Target) + typ = ptr + + case kindArray: + btfArr := raw.data.(*btfArray) + arr := &Array{nil, nil, btfArr.Nelems} + fixup(btfArr.IndexType, &arr.Index) + fixup(btfArr.Type, &arr.Type) + typ = arr + + case kindStruct: + members, err := convertMembers(raw.data.([]btfMember), raw.KindFlag()) + if err != nil { + return nil, fmt.Errorf("struct %s (id %d): %w", name, id, err) + } + typ = &Struct{name, raw.Size(), members} + + case kindUnion: + members, err := convertMembers(raw.data.([]btfMember), raw.KindFlag()) + if err != nil { + return nil, fmt.Errorf("union %s (id %d): %w", name, id, err) + } + typ = &Union{name, raw.Size(), members} + + case kindEnum: + rawvals := raw.data.([]btfEnum) + vals := make([]EnumValue, 0, len(rawvals)) + for i, btfVal := range rawvals { + name, err := rawStrings.Lookup(btfVal.NameOff) + if err != nil { + return nil, fmt.Errorf("get name for enum value %d: %s", i, err) + } + vals = append(vals, EnumValue{ + Name: name, + Value: btfVal.Val, + }) + } + typ = &Enum{name, raw.Size(), vals} + + case kindForward: + if raw.KindFlag() { + typ = &Fwd{name, FwdUnion} + } else { + typ = &Fwd{name, FwdStruct} + } + + case kindTypedef: + typedef := &Typedef{name, nil} + fixup(raw.Type(), &typedef.Type) + typ = typedef + + case kindVolatile: + volatile := &Volatile{nil} + fixup(raw.Type(), &volatile.Type) + typ = volatile + + case kindConst: + cnst := &Const{nil} + fixup(raw.Type(), &cnst.Type) + typ = cnst + + case kindRestrict: + restrict := &Restrict{nil} + fixup(raw.Type(), &restrict.Type) + typ = restrict + + case kindFunc: + fn := &Func{name, nil, raw.Linkage()} + fixup(raw.Type(), &fn.Type) + if err := assert(&fn.Type, reflect.TypeOf((*FuncProto)(nil))); err != nil { + return nil, err + } + typ = fn + + case kindFuncProto: + rawparams := raw.data.([]btfParam) + params := make([]FuncParam, 0, len(rawparams)) + for i, param := range rawparams { + name, err := rawStrings.Lookup(param.NameOff) + if err != nil { + return nil, fmt.Errorf("get name for func proto parameter %d: %s", i, err) + } + params = append(params, FuncParam{ + Name: name, + }) + } + for i := range params { + fixup(rawparams[i].Type, ¶ms[i].Type) + } + + fp := &FuncProto{nil, params} + fixup(raw.Type(), &fp.Return) + typ = fp + + case kindVar: + variable := raw.data.(*btfVariable) + v := &Var{name, nil, VarLinkage(variable.Linkage)} + fixup(raw.Type(), &v.Type) + typ = v + + case kindDatasec: + btfVars := raw.data.([]btfVarSecinfo) + vars := make([]VarSecinfo, 0, len(btfVars)) + for _, btfVar := range btfVars { + vars = append(vars, VarSecinfo{ + Offset: btfVar.Offset, + Size: btfVar.Size, + }) + } + for i := range vars { + fixup(btfVars[i].Type, &vars[i].Type) + if err := assert(&vars[i].Type, reflect.TypeOf((*Var)(nil))); err != nil { + return nil, err + } + } + typ = &Datasec{name, raw.SizeType, vars} + + case kindFloat: + typ = &Float{name, raw.Size()} + + default: + return nil, fmt.Errorf("type id %d: unknown kind: %v", id, raw.Kind()) + } + + types = append(types, typ) + } + + for _, fixup := range fixups { + i := int(fixup.id) + if i >= len(types)+len(baseTypes) { + return nil, fmt.Errorf("reference to invalid type id: %d", fixup.id) + } + if i < len(baseTypes) { + return nil, fmt.Errorf("fixup for base type id %d is not expected", i) + } + + *fixup.typ = types[i-len(baseTypes)] + } + + for _, bitfieldFixup := range bitfieldFixups { + if bitfieldFixup.id < TypeID(len(baseTypes)) { + return nil, fmt.Errorf("bitfield fixup from split to base types is not expected") + } + + data, ok := legacyBitfields[bitfieldFixup.id] + if ok { + // This is indeed a legacy bitfield, fix it up. + bitfieldFixup.m.Offset += data[0] + bitfieldFixup.m.BitfieldSize = data[1] + } + } + + for _, assertion := range assertions { + if reflect.TypeOf(*assertion.typ) != assertion.want { + return nil, fmt.Errorf("expected %s, got %T", assertion.want, *assertion.typ) + } + } + + return types, nil +} + +// essentialName represents the name of a BTF type stripped of any flavor +// suffixes after a ___ delimiter. +type essentialName string + +// newEssentialName returns name without a ___ suffix. +// +// CO-RE has the concept of 'struct flavors', which are used to deal with +// changes in kernel data structures. Anything after three underscores +// in a type name is ignored for the purpose of finding a candidate type +// in the kernel's BTF. +func newEssentialName(name string) essentialName { + if name == "" { + return "" + } + lastIdx := strings.LastIndex(name, "___") + if lastIdx > 0 { + return essentialName(name[:lastIdx]) + } + return essentialName(name) +} + +// UnderlyingType skips qualifiers and Typedefs. +func UnderlyingType(typ Type) Type { + result := typ + for depth := 0; depth <= maxTypeDepth; depth++ { + switch v := (result).(type) { + case qualifier: + result = v.qualify() + case *Typedef: + result = v.Type + default: + return result + } + } + return &cycle{typ} +} + +type formatState struct { + fmt.State + depth int +} + +// formattableType is a subset of Type, to ease unit testing of formatType. +type formattableType interface { + fmt.Formatter + TypeName() string +} + +// formatType formats a type in a canonical form. +// +// Handles cyclical types by only printing cycles up to a certain depth. Elements +// in extra are separated by spaces unless the preceding element is a string +// ending in '='. +func formatType(f fmt.State, verb rune, t formattableType, extra ...interface{}) { + if verb != 'v' && verb != 's' { + fmt.Fprintf(f, "{UNRECOGNIZED: %c}", verb) + return + } + + // This is the same as %T, but elides the package name. Assumes that + // formattableType is implemented by a pointer receiver. + goTypeName := reflect.TypeOf(t).Elem().Name() + _, _ = io.WriteString(f, goTypeName) + + if name := t.TypeName(); name != "" { + // Output BTF type name if present. + fmt.Fprintf(f, ":%q", name) + } + + if f.Flag('+') { + // Output address if requested. + fmt.Fprintf(f, ":%#p", t) + } + + if verb == 's' { + // %s omits details. + return + } + + var depth int + if ps, ok := f.(*formatState); ok { + depth = ps.depth + f = ps.State + } + + maxDepth, ok := f.Width() + if !ok { + maxDepth = 0 + } + + if depth > maxDepth { + // We've reached the maximum depth. This avoids infinite recursion even + // for cyclical types. + return + } + + if len(extra) == 0 { + return + } + + wantSpace := false + _, _ = io.WriteString(f, "[") + for _, arg := range extra { + if wantSpace { + _, _ = io.WriteString(f, " ") + } + + switch v := arg.(type) { + case string: + _, _ = io.WriteString(f, v) + wantSpace = len(v) > 0 && v[len(v)-1] != '=' + continue + + case formattableType: + v.Format(&formatState{f, depth + 1}, verb) + + default: + fmt.Fprint(f, arg) + } + + wantSpace = true + } + _, _ = io.WriteString(f, "]") +} |