Bump dependency opencontainers/runc@v1.0.0-rc10
This commit is contained in:
416
vendor/github.com/cilium/ebpf/asm/instruction.go
generated
vendored
Normal file
416
vendor/github.com/cilium/ebpf/asm/instruction.go
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vendored
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@@ -0,0 +1,416 @@
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package asm
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import (
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"encoding/binary"
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"fmt"
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"io"
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"math"
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"strings"
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"github.com/pkg/errors"
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)
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// InstructionSize is the size of a BPF instruction in bytes
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const InstructionSize = 8
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// Instruction is a single eBPF instruction.
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type Instruction struct {
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OpCode OpCode
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Dst Register
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Src Register
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Offset int16
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Constant int64
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Reference string
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Symbol string
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}
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// Sym creates a symbol.
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func (ins Instruction) Sym(name string) Instruction {
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ins.Symbol = name
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return ins
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}
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// Unmarshal decodes a BPF instruction.
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func (ins *Instruction) Unmarshal(r io.Reader, bo binary.ByteOrder) (uint64, error) {
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var bi bpfInstruction
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err := binary.Read(r, bo, &bi)
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if err != nil {
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return 0, err
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}
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ins.OpCode = bi.OpCode
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ins.Dst = bi.Registers.Dst()
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ins.Src = bi.Registers.Src()
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ins.Offset = bi.Offset
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ins.Constant = int64(bi.Constant)
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if !bi.OpCode.isDWordLoad() {
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return InstructionSize, nil
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}
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var bi2 bpfInstruction
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if err := binary.Read(r, bo, &bi2); err != nil {
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// No Wrap, to avoid io.EOF clash
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return 0, errors.New("64bit immediate is missing second half")
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}
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if bi2.OpCode != 0 || bi2.Offset != 0 || bi2.Registers != 0 {
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return 0, errors.New("64bit immediate has non-zero fields")
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}
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ins.Constant = int64(uint64(uint32(bi2.Constant))<<32 | uint64(uint32(bi.Constant)))
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return 2 * InstructionSize, nil
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}
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// Marshal encodes a BPF instruction.
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func (ins Instruction) Marshal(w io.Writer, bo binary.ByteOrder) (uint64, error) {
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if ins.OpCode == InvalidOpCode {
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return 0, errors.New("invalid opcode")
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}
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isDWordLoad := ins.OpCode.isDWordLoad()
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cons := int32(ins.Constant)
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if isDWordLoad {
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// Encode least significant 32bit first for 64bit operations.
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cons = int32(uint32(ins.Constant))
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}
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bpfi := bpfInstruction{
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ins.OpCode,
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newBPFRegisters(ins.Dst, ins.Src),
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ins.Offset,
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cons,
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}
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if err := binary.Write(w, bo, &bpfi); err != nil {
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return 0, err
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}
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if !isDWordLoad {
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return InstructionSize, nil
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}
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bpfi = bpfInstruction{
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Constant: int32(ins.Constant >> 32),
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}
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if err := binary.Write(w, bo, &bpfi); err != nil {
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return 0, err
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}
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return 2 * InstructionSize, nil
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}
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// RewriteMapPtr changes an instruction to use a new map fd.
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//
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// Returns an error if the fd is invalid, or the instruction
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// is incorrect.
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func (ins *Instruction) RewriteMapPtr(fd int) error {
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if !ins.OpCode.isDWordLoad() {
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return errors.Errorf("%s is not a 64 bit load", ins.OpCode)
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}
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if fd < 0 {
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return errors.New("invalid fd")
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}
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ins.Src = R1
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ins.Constant = int64(fd)
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return nil
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}
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// Format implements fmt.Formatter.
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func (ins Instruction) Format(f fmt.State, c rune) {
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if c != 'v' {
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fmt.Fprintf(f, "{UNRECOGNIZED: %c}", c)
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return
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}
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op := ins.OpCode
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if op == InvalidOpCode {
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fmt.Fprint(f, "INVALID")
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return
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}
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// Omit trailing space for Exit
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if op.JumpOp() == Exit {
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fmt.Fprint(f, op)
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return
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}
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fmt.Fprintf(f, "%v ", op)
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switch cls := op.Class(); cls {
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case LdClass, LdXClass, StClass, StXClass:
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switch op.Mode() {
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case ImmMode:
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fmt.Fprintf(f, "dst: %s imm: %d", ins.Dst, ins.Constant)
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case AbsMode:
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fmt.Fprintf(f, "imm: %d", ins.Constant)
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case IndMode:
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fmt.Fprintf(f, "dst: %s src: %s imm: %d", ins.Dst, ins.Src, ins.Constant)
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case MemMode:
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fmt.Fprintf(f, "dst: %s src: %s off: %d imm: %d", ins.Dst, ins.Src, ins.Offset, ins.Constant)
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case XAddMode:
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fmt.Fprintf(f, "dst: %s src: %s", ins.Dst, ins.Src)
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}
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case ALU64Class, ALUClass:
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fmt.Fprintf(f, "dst: %s ", ins.Dst)
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if op.ALUOp() == Swap || op.Source() == ImmSource {
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fmt.Fprintf(f, "imm: %d", ins.Constant)
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} else {
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fmt.Fprintf(f, "src: %s", ins.Src)
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}
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case JumpClass:
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switch jop := op.JumpOp(); jop {
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case Call:
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if ins.Src == R1 {
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// bpf-to-bpf call
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fmt.Fprint(f, ins.Constant)
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} else {
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fmt.Fprint(f, BuiltinFunc(ins.Constant))
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}
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default:
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fmt.Fprintf(f, "dst: %s off: %d ", ins.Dst, ins.Offset)
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if op.Source() == ImmSource {
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fmt.Fprintf(f, "imm: %d", ins.Constant)
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} else {
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fmt.Fprintf(f, "src: %s", ins.Src)
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}
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}
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}
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if ins.Reference != "" {
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fmt.Fprintf(f, " <%s>", ins.Reference)
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}
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}
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// Instructions is an eBPF program.
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type Instructions []Instruction
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func (insns Instructions) String() string {
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return fmt.Sprint(insns)
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}
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// RewriteMapPtr rewrites all loads of a specific map pointer to a new fd.
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//
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// Returns an error if the symbol isn't used, see IsUnreferencedSymbol.
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func (insns Instructions) RewriteMapPtr(symbol string, fd int) error {
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if symbol == "" {
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return errors.New("empty symbol")
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}
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found := false
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for i := range insns {
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ins := &insns[i]
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if ins.Reference != symbol {
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continue
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}
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if err := ins.RewriteMapPtr(fd); err != nil {
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return err
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}
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found = true
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}
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if !found {
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return &unreferencedSymbolError{symbol}
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}
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return nil
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}
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// SymbolOffsets returns the set of symbols and their offset in
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// the instructions.
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func (insns Instructions) SymbolOffsets() (map[string]int, error) {
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offsets := make(map[string]int)
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for i, ins := range insns {
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if ins.Symbol == "" {
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continue
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}
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if _, ok := offsets[ins.Symbol]; ok {
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return nil, errors.Errorf("duplicate symbol %s", ins.Symbol)
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}
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offsets[ins.Symbol] = i
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}
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return offsets, nil
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}
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// ReferenceOffsets returns the set of references and their offset in
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// the instructions.
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func (insns Instructions) ReferenceOffsets() map[string][]int {
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offsets := make(map[string][]int)
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for i, ins := range insns {
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if ins.Reference == "" {
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continue
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}
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offsets[ins.Reference] = append(offsets[ins.Reference], i)
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}
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return offsets
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}
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func (insns Instructions) marshalledOffsets() (map[string]int, error) {
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symbols := make(map[string]int)
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marshalledPos := 0
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for _, ins := range insns {
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currentPos := marshalledPos
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marshalledPos += ins.OpCode.marshalledInstructions()
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if ins.Symbol == "" {
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continue
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}
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if _, ok := symbols[ins.Symbol]; ok {
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return nil, errors.Errorf("duplicate symbol %s", ins.Symbol)
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}
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symbols[ins.Symbol] = currentPos
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}
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return symbols, nil
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}
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// Format implements fmt.Formatter.
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//
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// You can control indentation of symbols by
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// specifying a width. Setting a precision controls the indentation of
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// instructions.
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// The default character is a tab, which can be overriden by specifying
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// the ' ' space flag.
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func (insns Instructions) Format(f fmt.State, c rune) {
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if c != 's' && c != 'v' {
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fmt.Fprintf(f, "{UNKNOWN FORMAT '%c'}", c)
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return
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}
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// Precision is better in this case, because it allows
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// specifying 0 padding easily.
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padding, ok := f.Precision()
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if !ok {
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padding = 1
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}
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indent := strings.Repeat("\t", padding)
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if f.Flag(' ') {
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indent = strings.Repeat(" ", padding)
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}
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symPadding, ok := f.Width()
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if !ok {
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symPadding = padding - 1
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}
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if symPadding < 0 {
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symPadding = 0
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}
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symIndent := strings.Repeat("\t", symPadding)
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if f.Flag(' ') {
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symIndent = strings.Repeat(" ", symPadding)
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}
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// Figure out how many digits we need to represent the highest
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// offset.
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highestOffset := 0
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for _, ins := range insns {
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highestOffset += ins.OpCode.marshalledInstructions()
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}
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offsetWidth := int(math.Ceil(math.Log10(float64(highestOffset))))
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offset := 0
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for _, ins := range insns {
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if ins.Symbol != "" {
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fmt.Fprintf(f, "%s%s:\n", symIndent, ins.Symbol)
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}
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fmt.Fprintf(f, "%s%*d: %v\n", indent, offsetWidth, offset, ins)
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offset += ins.OpCode.marshalledInstructions()
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}
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return
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}
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// Marshal encodes a BPF program into the kernel format.
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func (insns Instructions) Marshal(w io.Writer, bo binary.ByteOrder) error {
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absoluteOffsets, err := insns.marshalledOffsets()
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if err != nil {
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return err
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}
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num := 0
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for i, ins := range insns {
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switch {
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case ins.OpCode.JumpOp() == Call && ins.Constant == -1:
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// Rewrite bpf to bpf call
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offset, ok := absoluteOffsets[ins.Reference]
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if !ok {
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return errors.Errorf("instruction %d: reference to missing symbol %s", i, ins.Reference)
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}
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ins.Constant = int64(offset - num - 1)
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case ins.OpCode.Class() == JumpClass && ins.Offset == -1:
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// Rewrite jump to label
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offset, ok := absoluteOffsets[ins.Reference]
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if !ok {
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return errors.Errorf("instruction %d: reference to missing symbol %s", i, ins.Reference)
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}
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ins.Offset = int16(offset - num - 1)
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}
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n, err := ins.Marshal(w, bo)
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if err != nil {
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return errors.Wrapf(err, "instruction %d", i)
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}
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num += int(n / InstructionSize)
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}
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return nil
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}
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type bpfInstruction struct {
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OpCode OpCode
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Registers bpfRegisters
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Offset int16
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Constant int32
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}
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type bpfRegisters uint8
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func newBPFRegisters(dst, src Register) bpfRegisters {
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return bpfRegisters((src << 4) | (dst & 0xF))
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}
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func (r bpfRegisters) Dst() Register {
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return Register(r & 0xF)
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}
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func (r bpfRegisters) Src() Register {
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return Register(r >> 4)
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}
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type unreferencedSymbolError struct {
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symbol string
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}
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func (use *unreferencedSymbolError) Error() string {
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return fmt.Sprintf("unreferenced symbol %s", use.symbol)
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}
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// IsUnreferencedSymbol returns true if err was caused by
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// an unreferenced symbol.
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func IsUnreferencedSymbol(err error) bool {
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_, ok := err.(*unreferencedSymbolError)
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return ok
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}
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Reference in New Issue
Block a user