package btf

var (
	ErrNotSupported   = internal.ErrNotSupported
	ErrNotFound       = errors.New("not found")
	ErrNoExtendedInfo = errors.New("no extended info")
)

Errors returned by BTF functions.

Functions ¶

func Sizeof ¶

func Sizeof(typ Type) (int, error)

Sizeof returns the size of a type in bytes.

Returns an error if the size can't be computed.

Types ¶

type Array ¶

type Array struct {
	TypeID
	Type   Type
	Nelems uint32
}

Array is an array with a fixed number of elements.

func (*Array) String ¶

func (arr *Array) String() string

type COREFixup ¶

type COREFixup struct {
	Kind   COREKind
	Local  uint32
	Target uint32
	Poison bool
}

COREFixup is the result of computing a CO-RE relocation for a target.

func (COREFixup) String ¶

func (f COREFixup) String() string

type COREFixups ¶

type COREFixups map[uint64]COREFixup

func (COREFixups) Apply ¶

func (fs COREFixups) Apply(insns asm.Instructions) (asm.Instructions, error)

Apply a set of CO-RE relocations to a BPF program.

type COREKind ¶

type COREKind uint32

COREKind is the type of CO-RE relocation

func (COREKind) String ¶

func (k COREKind) String() string

type Const ¶

type Const struct {
	TypeID
	Type Type
}

Const is a qualifier.

func (*Const) String ¶

func (c *Const) String() string

type Datasec ¶

type Datasec struct {
	TypeID
	Name string
	Size uint32
	Vars []VarSecinfo
}

Datasec is a global program section containing data.

func (*Datasec) String ¶

func (ds *Datasec) String() string

func (*Datasec) TypeName ¶

func (ds *Datasec) TypeName() string

type Enum ¶

type Enum struct {
	TypeID
	Name   string
	Values []EnumValue
}

Enum lists possible values.

func (*Enum) String ¶

func (e *Enum) String() string

func (*Enum) TypeName ¶

func (e *Enum) TypeName() string

type EnumValue ¶

type EnumValue struct {
	Name  string
	Value int32
}

EnumValue is part of an Enum

Is is not a valid Type

type Float ¶

type Float struct {
	TypeID
	Name string

	// The size of the float in bytes.
	Size uint32
}

Float is a float of a given length.

func (*Float) String ¶

func (f *Float) String() string

func (*Float) TypeName ¶

func (f *Float) TypeName() string

type Func ¶

type Func struct {
	TypeID
	Name    string
	Type    Type
	Linkage FuncLinkage
}

Func is a function definition.

func (*Func) String ¶

func (f *Func) String() string

func (*Func) TypeName ¶

func (f *Func) TypeName() string

type FuncLinkage ¶

type FuncLinkage int

FuncLinkage describes BTF function linkage metadata.

const (
	StaticFunc FuncLinkage = iota // static
	GlobalFunc                    // global
	ExternFunc                    // extern
)

Equivalent of enum btf_func_linkage.

func (FuncLinkage) String ¶

func (i FuncLinkage) String() string

type FuncParam ¶

type FuncParam struct {
	Name string
	Type Type
}

type FuncProto ¶

type FuncProto struct {
	TypeID
	Return Type
	Params []FuncParam
}

FuncProto is a function declaration.

func (*FuncProto) String ¶

func (fp *FuncProto) String() string

type Fwd ¶

type Fwd struct {
	TypeID
	Name string
	Kind FwdKind
}

Fwd is a forward declaration of a Type.

func (*Fwd) String ¶

func (f *Fwd) String() string

func (*Fwd) TypeName ¶

func (f *Fwd) TypeName() string

type FwdKind ¶

type FwdKind int

FwdKind is the type of forward declaration.

const (
	FwdStruct FwdKind = iota
	FwdUnion
)

Valid types of forward declaration.

func (FwdKind) String ¶

func (fk FwdKind) String() string

type Handle ¶

type Handle struct {
	// contains filtered or unexported fields
}

Handle is a reference to BTF loaded into the kernel.

func NewHandle ¶

func NewHandle(spec *Spec) (*Handle, error)

NewHandle loads BTF into the kernel.

Returns ErrNotSupported if BTF is not supported.

func NewHandleFromID ¶

func NewHandleFromID(id ID) (*Handle, error)

NewHandleFromID returns the BTF handle for a given id.

Returns ErrNotExist, if there is no BTF with the given id.

Requires CAP_SYS_ADMIN.

func (*Handle) Close ¶

func (h *Handle) Close() error

Close destroys the handle.

Subsequent calls to FD will return an invalid value.

func (*Handle) FD ¶

func (h *Handle) FD() int

FD returns the file descriptor for the handle.

func (*Handle) Spec ¶

func (h *Handle) Spec() *Spec

Spec returns the Spec that defined the BTF loaded into the kernel.

type ID ¶

type ID uint32

ID represents the unique ID of a BTF object.

type Int ¶

type Int struct {
	TypeID
	Name string

	// The size of the integer in bytes.
	Size     uint32
	Encoding IntEncoding
	// OffsetBits is the starting bit offset. Currently always 0.
	// See https://www.kernel.org/doc/html/latest/bpf/btf.html#btf-kind-int
	OffsetBits uint32
	Bits       byte
}

Int is an integer of a given length.

func (*Int) String ¶

func (i *Int) String() string

func (*Int) TypeName ¶

func (i *Int) TypeName() string

type IntEncoding ¶

type IntEncoding byte

const (
	Signed IntEncoding = 1 << iota
	Char
	Bool
)

type Map ¶

type Map struct {
	Spec       *Spec
	Key, Value Type
}

Map is the BTF for a map.

type Member ¶

type Member struct {
	Name string
	Type Type
	// OffsetBits is the bit offset of this member.
	OffsetBits   uint32
	BitfieldSize uint32
}

Member is part of a Struct or Union.

It is not a valid Type.

type NamedType ¶

type NamedType interface {
	Type

	// Name of the type, empty for anonymous types.
	TypeName() string
}

NamedType is a type with a name.

type Pointer ¶

type Pointer struct {
	TypeID
	Target Type
}

Pointer is a pointer to another type.

func (*Pointer) String ¶

func (p *Pointer) String() string

type Program ¶

type Program struct {
	// contains filtered or unexported fields
}

Program is the BTF information for a stream of instructions.

func (*Program) Append ¶

func (p *Program) Append(other *Program) error

Append the information from other to the Program.

func (*Program) Fixups ¶

func (p *Program) Fixups(target *Spec) (COREFixups, error)

Fixups returns the changes required to adjust the program to the target.

Passing a nil target will relocate against the running kernel.

func (*Program) FuncInfos ¶

func (p *Program) FuncInfos() (recordSize uint32, bytes []byte, err error)

FuncInfos returns the binary form of BTF function infos.

func (*Program) LineInfos ¶

func (p *Program) LineInfos() (recordSize uint32, bytes []byte, err error)

LineInfos returns the binary form of BTF line infos.

func (*Program) Spec ¶

func (p *Program) Spec() *Spec

Spec returns the BTF spec of this program.

type Restrict ¶

type Restrict struct {
	TypeID
	Type Type
}

Restrict is a qualifier.

func (*Restrict) String ¶

func (r *Restrict) String() string

type Spec ¶

type Spec struct {
	// contains filtered or unexported fields
}

Spec represents decoded BTF.

func LoadKernelSpec ¶

func LoadKernelSpec() (*Spec, error)

LoadKernelSpec returns the current kernel's BTF information.

Requires a >= 5.5 kernel with CONFIG_DEBUG_INFO_BTF enabled. Returns ErrNotSupported if BTF is not enabled.

func LoadRawSpec ¶

func LoadRawSpec(btf io.Reader, bo binary.ByteOrder) (*Spec, error)

LoadRawSpec reads a blob of BTF data that isn't wrapped in an ELF file.

Prefer using LoadSpecFromReader, since this function only supports a subset of BTF.

func LoadSpecFromReader ¶

func LoadSpecFromReader(rd io.ReaderAt) (*Spec, error)

LoadSpecFromReader reads BTF sections from an ELF.

Returns ErrNotFound if the reader contains no BTF.

func (*Spec) Copy ¶

func (s *Spec) Copy() *Spec

Copy creates a copy of Spec.

func (*Spec) FindType ¶

func (s *Spec) FindType(name string, typ interface{}) error

FindType searches for a type with a specific name.

Called T a type that satisfies Type, typ must be a non-nil **T. On success, the address of the found type will be copied in typ.

Returns an error wrapping ErrNotFound if no matching type exists in spec.

Example¶

Code:

{
	// Acquire a Spec via one of its constructors.
	spec := new(Spec)

	// Declare a variable of the desired type
	var foo *Struct

	if err := spec.FindType("foo", &foo); err != nil {
		// There is no struct with name foo, or there
		// are multiple possibilities.
	}

	// We've found struct foo
	fmt.Println(foo.Name)
}

func (*Spec) Program ¶

func (s *Spec) Program(name string, length uint64) (*Program, error)

Program finds the BTF for a specific section.

Length is the number of bytes in the raw BPF instruction stream.

Returns an error which may wrap ErrNoExtendedInfo if the Spec doesn't contain extended BTF info.

type Struct ¶

type Struct struct {
	TypeID
	Name string
	// The size of the struct including padding, in bytes
	Size    uint32
	Members []Member
}

Struct is a compound type of consecutive members.

func (*Struct) String ¶

func (s *Struct) String() string

func (*Struct) TypeName ¶

func (s *Struct) TypeName() string

type Type ¶

type Type interface {
	ID() TypeID

	String() string
	// contains filtered or unexported methods
}

Type represents a type described by BTF.

Example (ValidTypes)¶

The following are valid Types.

There currently is no better way to document which types implement an interface.

Code:

{
	var _ Type = &Void{}
	var _ Type = &Int{}
	var _ Type = &Pointer{}
	var _ Type = &Array{}
	var _ Type = &Struct{}
	var _ Type = &Union{}
	var _ Type = &Enum{}
	var _ Type = &Fwd{}
	var _ Type = &Typedef{}
	var _ Type = &Volatile{}
	var _ Type = &Const{}
	var _ Type = &Restrict{}
	var _ Type = &Func{}
	var _ Type = &FuncProto{}
	var _ Type = &Var{}
	var _ Type = &Datasec{}
}

type TypeID ¶

type TypeID uint32

TypeID identifies a type in a BTF section.

func (TypeID) ID ¶

func (tid TypeID) ID() TypeID

ID implements part of the Type interface.

type Typedef ¶

type Typedef struct {
	TypeID
	Name string
	Type Type
}

Typedef is an alias of a Type.

func (*Typedef) String ¶

func (td *Typedef) String() string

func (*Typedef) TypeName ¶

func (td *Typedef) TypeName() string

type Union ¶

type Union struct {
	TypeID
	Name string
	// The size of the union including padding, in bytes.
	Size    uint32
	Members []Member
}

Union is a compound type where members occupy the same memory.

func (*Union) String ¶

func (u *Union) String() string

func (*Union) TypeName ¶

func (u *Union) TypeName() string

type Var ¶

type Var struct {
	TypeID
	Name    string
	Type    Type
	Linkage VarLinkage
}

Var is a global variable.

func (*Var) String ¶

func (v *Var) String() string

func (*Var) TypeName ¶

func (v *Var) TypeName() string

type VarLinkage ¶

type VarLinkage int

VarLinkage describes BTF variable linkage metadata.

const (
	StaticVar VarLinkage = iota // static
	GlobalVar                   // global
	ExternVar                   // extern
)

func (VarLinkage) String ¶

func (i VarLinkage) String() string

type VarSecinfo ¶

type VarSecinfo struct {
	Type   Type
	Offset uint32
	Size   uint32
}

VarSecinfo describes variable in a Datasec.

It is not a valid Type.

type Void ¶

type Void struct{}

Void is the unit type of BTF.

func (*Void) ID ¶

func (v *Void) ID() TypeID

func (*Void) String ¶

func (v *Void) String() string

type Volatile ¶

type Volatile struct {
	TypeID
	Type Type
}

Volatile is a qualifier.

func (*Volatile) String ¶

func (v *Volatile) String() string

Source Files ¶

btf.go btf_types.go btf_types_string.go core.go doc.go ext_info.go info.go strings.go syscalls.go types.go

Version: v0.7.0
Published: Oct 8, 2021
Platform: js/wasm
Imports: 18 packages
Last checked: 1 hour ago –

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