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         var txSigHash *[]byte
  57         txSigHashFn := func() []byte {
  58                 if txSigHash == nil {
  59                         hasher := sha3pool.Get256()
  60                         defer sha3pool.Put256(hasher)
  61
  62                         entryID.WriteTo(hasher)
  63                         tx.ID.WriteTo(hasher)
  64
  65                         var hash bc.Hash
  66                         hash.ReadFrom(hasher)
  67                         hashBytes := hash.Bytes()
  68                         txSigHash = &hashBytes
  69                 }
  70                 return *txSigHash
  71         }
  72
  73         ec := &entryContext{
  74                 entry:   entry,
  75                 entries: tx.Entries,
  76         }
  77
  78         result := &vm.Context{
  79                 VMVersion: prog.VmVersion,
  80                 Code:      witnessProgram(prog.Code),
  81                 Arguments: args,
  82
  83                 EntryID: entryID.Bytes(),
  84
  85                 TxVersion:   &tx.Version,
  86                 BlockHeight: &blockHeight,
  87
  88                 TxSigHash:     txSigHashFn,
  89                 NumResults:    &numResults,
  90                 AssetID:       assetID,
  91                 Amount:        amount,
  92                 DestPos:       destPos,
  93                 SpentOutputID: spentOutputID,
  94                 CheckOutput:   ec.checkOutput,
  95         }
  96
  97         return result
  98 }
  99
 100 func witnessProgram(prog []byte) []byte {
 101         if segwit.IsP2WPKHScript(prog) {
 102                 if witnessProg, err := segwit.ConvertP2PKHSigProgram([]byte(prog)); err == nil {
 103                         return witnessProg
 104                 }
 105         } else if segwit.IsP2WSHScript(prog) {
 106                 if witnessProg, err := segwit.ConvertP2SHProgram([]byte(prog)); err == nil {
 107                         return witnessProg
 108                 }
 109         }
 110         return prog
 111 }
 112
 113 type entryContext struct {
 114         entry   bc.Entry
 115         entries map[bc.Hash]bc.Entry
 116 }
 117
 118 func (ec *entryContext) checkOutput(index uint64, amount uint64, assetID []byte, vmVersion uint64, code []byte, expansion bool) (bool, error) {
 119         checkEntry := func(e bc.Entry) (bool, error) {
 120                 check := func(prog *bc.Program, value *bc.AssetAmount) bool {
 121                         return (prog.VmVersion == vmVersion &&
 122                                 bytes.Equal(prog.Code, code) &&
 123                                 bytes.Equal(value.AssetId.Bytes(), assetID) &&
 124                                 value.Amount == amount)
 125                 }
 126
 127                 switch e := e.(type) {
 128                 case *bc.IntraChainOutput:
 129                         return check(e.ControlProgram, e.Source.Value), nil
 130
 131                 case *bc.VoteOutput:
 132                         return check(e.ControlProgram, e.Source.Value), nil
 133
 134                 case *bc.Retirement:
 135                         var prog bc.Program
 136                         if expansion {
 137                                 // The spec requires prog.Code to be the empty string only
 138                                 // when !expansion. When expansion is true, we prepopulate
 139                                 // prog.Code to give check() a freebie match.
 140                                 //
 141                                 // (The spec always requires prog.VmVersion to be zero.)
 142                                 prog.Code = code
 143                         }
 144                         return check(&prog, e.Source.Value), nil
 145                 }
 146
 147                 return false, vm.ErrContext
 148         }
 149
 150         checkMux := func(m *bc.Mux) (bool, error) {
 151                 if index >= uint64(len(m.WitnessDestinations)) {
 152                         return false, errors.Wrapf(vm.ErrBadValue, "index %d >= %d", index, len(m.WitnessDestinations))
 153                 }
 154                 eID := m.WitnessDestinations[index].Ref
 155                 e, ok := ec.entries[*eID]
 156                 if !ok {
 157                         return false, errors.Wrapf(bc.ErrMissingEntry, "entry for mux destination %d, id %x, not found", index, eID.Bytes())
 158                 }
 159                 return checkEntry(e)
 160         }
 161
 162         switch e := ec.entry.(type) {
 163         case *bc.Mux:
 164                 return checkMux(e)
 165
 166         case *bc.Spend:
 167                 d, ok := ec.entries[*e.WitnessDestination.Ref]
 168                 if !ok {
 169                         return false, errors.Wrapf(bc.ErrMissingEntry, "entry for spend destination %x not found", e.WitnessDestination.Ref.Bytes())
 170                 }
 171                 if m, ok := d.(*bc.Mux); ok {
 172                         return checkMux(m)
 173                 }
 174                 if index != 0 {
 175                         return false, errors.Wrapf(vm.ErrBadValue, "index %d >= 1", index)
 176                 }
 177                 return checkEntry(d)
 178
 179         case *bc.VetoInput:
 180                 d, ok := ec.entries[*e.WitnessDestination.Ref]
 181                 if !ok {
 182                         return false, errors.Wrapf(bc.ErrMissingEntry, "entry for vetoInput destination %x not found", e.WitnessDestination.Ref.Bytes())
 183                 }
 184                 if m, ok := d.(*bc.Mux); ok {
 185                         return checkMux(m)
 186                 }
 187                 if index != 0 {
 188                         return false, errors.Wrapf(vm.ErrBadValue, "index %d >= 1", index)
 189                 }
 190                 return checkEntry(d)
 191         }
 192
 193         return false, vm.ErrContext
 194 }