protocol/validation/vmcontext.go

   1 package validation
   2
   3 import (
   4         "bytes"
   5
   6         "github.com/vapor/consensus/segwit"
   7         "github.com/vapor/crypto/sha3pool"
   8         "github.com/vapor/errors"
   9         "github.com/vapor/protocol/bc"
  10         "github.com/vapor/protocol/vm"
  11 )
  12
  13 // NewTxVMContext generates the vm.Context for BVM
  14 func NewTxVMContext(vs *validationState, entry bc.Entry, prog *bc.Program, args [][]byte) *vm.Context {
  15         var (
  16                 tx          = vs.tx
  17                 blockHeight = vs.block.BlockHeader.GetHeight()
  18                 numResults  = uint64(len(tx.ResultIds))
  19                 entryID     = bc.EntryID(entry) // TODO(bobg): pass this in, don't recompute it
  20
  21                 assetID       *[]byte
  22                 amount        *uint64
  23                 destPos       *uint64
  24                 spentOutputID *[]byte
  25         )
  26
  27         switch e := entry.(type) {
  28         case *bc.CrossChainInput:
  29                 mainchainOutput := tx.Entries[*e.MainchainOutputId].(*bc.IntraChainOutput)
  30                 a1 := mainchainOutput.Source.Value.AssetId.Bytes()
  31                 assetID = &a1
  32                 amount = &mainchainOutput.Source.Value.Amount
  33                 destPos = &e.WitnessDestination.Position
  34                 s := e.MainchainOutputId.Bytes()
  35                 spentOutputID = &s
  36
  37         case *bc.Spend:
  38                 spentOutput := tx.Entries[*e.SpentOutputId].(*bc.IntraChainOutput)
  39                 a1 := spentOutput.Source.Value.AssetId.Bytes()
  40                 assetID = &a1
  41                 amount = &spentOutput.Source.Value.Amount
  42                 destPos = &e.WitnessDestination.Position
  43                 s := e.SpentOutputId.Bytes()
  44                 spentOutputID = &s
  45
  46         case *bc.VetoInput:
  47                 voteOutput := tx.Entries[*e.SpentOutputId].(*bc.VoteOutput)
  48                 a1 := voteOutput.Source.Value.AssetId.Bytes()
  49                 assetID = &a1
  50                 amount = &voteOutput.Source.Value.Amount
  51                 destPos = &e.WitnessDestination.Position
  52                 s := e.SpentOutputId.Bytes()
  53                 spentOutputID = &s
  54
  55         }
  56
  57         var txSigHash *[]byte
  58         txSigHashFn := func() []byte {
  59                 if txSigHash == nil {
  60                         hasher := sha3pool.Get256()
  61                         defer sha3pool.Put256(hasher)
  62
  63                         entryID.WriteTo(hasher)
  64                         tx.ID.WriteTo(hasher)
  65
  66                         var hash bc.Hash
  67                         hash.ReadFrom(hasher)
  68                         hashBytes := hash.Bytes()
  69                         txSigHash = &hashBytes
  70                 }
  71                 return *txSigHash
  72         }
  73
  74         ec := &entryContext{
  75                 entry:   entry,
  76                 entries: tx.Entries,
  77         }
  78
  79         result := &vm.Context{
  80                 VMVersion: prog.VmVersion,
  81                 Code:      witnessProgram(prog.Code),
  82                 Arguments: args,
  83
  84                 EntryID: entryID.Bytes(),
  85
  86                 TxVersion:   &tx.Version,
  87                 BlockHeight: &blockHeight,
  88
  89                 TxSigHash:     txSigHashFn,
  90                 NumResults:    &numResults,
  91                 AssetID:       assetID,
  92                 Amount:        amount,
  93                 DestPos:       destPos,
  94                 SpentOutputID: spentOutputID,
  95                 CheckOutput:   ec.checkOutput,
  96         }
  97
  98         return result
  99 }
 100
 101 func witnessProgram(prog []byte) []byte {
 102         if segwit.IsP2WPKHScript(prog) {
 103                 if witnessProg, err := segwit.ConvertP2PKHSigProgram([]byte(prog)); err == nil {
 104                         return witnessProg
 105                 }
 106         } else if segwit.IsP2WSHScript(prog) {
 107                 if witnessProg, err := segwit.ConvertP2SHProgram([]byte(prog)); err == nil {
 108                         return witnessProg
 109                 }
 110         }
 111         return prog
 112 }
 113
 114 type entryContext struct {
 115         entry   bc.Entry
 116         entries map[bc.Hash]bc.Entry
 117 }
 118
 119 func (ec *entryContext) checkOutput(index uint64, amount uint64, assetID []byte, vmVersion uint64, code []byte, expansion bool) (bool, error) {
 120         checkEntry := func(e bc.Entry) (bool, error) {
 121                 check := func(prog *bc.Program, value *bc.AssetAmount) bool {
 122                         return (prog.VmVersion == vmVersion &&
 123                                 bytes.Equal(prog.Code, code) &&
 124                                 bytes.Equal(value.AssetId.Bytes(), assetID) &&
 125                                 value.Amount == amount)
 126                 }
 127
 128                 switch e := e.(type) {
 129                 case *bc.IntraChainOutput:
 130                         return check(e.ControlProgram, e.Source.Value), nil
 131
 132                 case *bc.VoteOutput:
 133                         return check(e.ControlProgram, e.Source.Value), nil
 134
 135                 case *bc.Retirement:
 136                         var prog bc.Program
 137                         if expansion {
 138                                 // The spec requires prog.Code to be the empty string only
 139                                 // when !expansion. When expansion is true, we prepopulate
 140                                 // prog.Code to give check() a freebie match.
 141                                 //
 142                                 // (The spec always requires prog.VmVersion to be zero.)
 143                                 prog.Code = code
 144                         }
 145                         return check(&prog, e.Source.Value), nil
 146                 }
 147
 148                 return false, vm.ErrContext
 149         }
 150
 151         checkMux := func(m *bc.Mux) (bool, error) {
 152                 if index >= uint64(len(m.WitnessDestinations)) {
 153                         return false, errors.Wrapf(vm.ErrBadValue, "index %d >= %d", index, len(m.WitnessDestinations))
 154                 }
 155                 eID := m.WitnessDestinations[index].Ref
 156                 e, ok := ec.entries[*eID]
 157                 if !ok {
 158                         return false, errors.Wrapf(bc.ErrMissingEntry, "entry for mux destination %d, id %x, not found", index, eID.Bytes())
 159                 }
 160                 return checkEntry(e)
 161         }
 162
 163         switch e := ec.entry.(type) {
 164         case *bc.Mux:
 165                 return checkMux(e)
 166
 167         case *bc.Spend:
 168                 d, ok := ec.entries[*e.WitnessDestination.Ref]
 169                 if !ok {
 170                         return false, errors.Wrapf(bc.ErrMissingEntry, "entry for spend destination %x not found", e.WitnessDestination.Ref.Bytes())
 171                 }
 172                 if m, ok := d.(*bc.Mux); ok {
 173                         return checkMux(m)
 174                 }
 175                 if index != 0 {
 176                         return false, errors.Wrapf(vm.ErrBadValue, "index %d >= 1", index)
 177                 }
 178                 return checkEntry(d)
 179
 180         case *bc.VetoInput:
 181                 d, ok := ec.entries[*e.WitnessDestination.Ref]
 182                 if !ok {
 183                         return false, errors.Wrapf(bc.ErrMissingEntry, "entry for vetoInput destination %x not found", e.WitnessDestination.Ref.Bytes())
 184                 }
 185                 if m, ok := d.(*bc.Mux); ok {
 186                         return checkMux(m)
 187                 }
 188                 if index != 0 {
 189                         return false, errors.Wrapf(vm.ErrBadValue, "index %d >= 1", index)
 190                 }
 191                 return checkEntry(d)
 192         }
 193
 194         return false, vm.ErrContext
 195 }