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package vm
import (
"encoding/hex"
"fmt"
ptypes "github.com/eris-ltd/eris-db/permission/types"
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)
//------------------------------------------------------------------------------------------------
// Registered SNative contracts
var PermissionsContract = "permissions_contract"
func registerSNativeContracts() {
registeredNativeContracts[LeftPadWord256([]byte(PermissionsContract))] = permissionsContract
/*
// we could expose these but we moved permission and args checks into the permissionsContract
// so calling them would be unsafe ...
registeredNativeContracts[LeftPadWord256([]byte("has_base"))] = has_base
registeredNativeContracts[LeftPadWord256([]byte("set_base"))] = set_base
registeredNativeContracts[LeftPadWord256([]byte("unset_base"))] = unset_base
registeredNativeContracts[LeftPadWord256([]byte("set_global"))] = set_global
registeredNativeContracts[LeftPadWord256([]byte("has_role"))] = has_role
registeredNativeContracts[LeftPadWord256([]byte("add_role"))] = add_role
registeredNativeContracts[LeftPadWord256([]byte("rm_role"))] = rm_role
*/
}
//-----------------------------------------------------------------------------
// snative are native contracts that can access and modify an account's permissions
type SNativeFuncDescription struct {
Name string
NArgs int
PermFlag ptypes.PermFlag
F NativeContract
}
/* The solidity interface used to generate the abi function ids below
contract Permissions {
function has_base(address addr, int permFlag) constant returns (bool value) {}
function set_base(address addr, int permFlag, bool value) constant returns (bool val) {}
function unset_base(address addr, int permFlag) constant returns (int pf) {}
function set_global(address addr, int permFlag, bool value) constant returns (int pf) {}
function has_role(address addr, string role) constant returns (bool val) {}
function add_role(address addr, string role) constant returns (bool added) {}
function rm_role(address addr, string role) constant returns (bool removed) {}
}
*/
// function identifiers from the solidity abi
var PermsMap = map[string]SNativeFuncDescription{
"e8145855": SNativeFuncDescription{"has_role", 2, ptypes.HasRole, has_role},
"180d26f2": SNativeFuncDescription{"unset_base", 2, ptypes.UnsetBase, unset_base},
"3a3fcc59": SNativeFuncDescription{"set_global", 2, ptypes.SetGlobal, set_global},
"3fbf7da5": SNativeFuncDescription{"add_role", 2, ptypes.AddRole, add_role},
"9ea53314": SNativeFuncDescription{"set_base", 3, ptypes.SetBase, set_base},
"bb37737a": SNativeFuncDescription{"has_base", 2, ptypes.HasBase, has_base},
"28fd0194": SNativeFuncDescription{"rm_role", 2, ptypes.RmRole, rm_role},
func getFuncIdentifiersFromSignature(string) string {
}
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func permissionsContract(appState AppState, caller *Account, args []byte, gas *int64) (output []byte, err error) {
if len(args) < 4 {
return nil, fmt.Errorf("permissionsContract expects at least a 4-byte function identifier")
}
// map solidity abi function id to snative
funcIDbytes := args[:4]
args = args[4:]
funcID := hex.EncodeToString(funcIDbytes)
d, ok := PermsMap[funcID]
if !ok {
return nil, fmt.Errorf("unknown permissionsContract funcID %s", funcID)
}
// check if we have permission to call this function
if !HasPermission(appState, caller, d.PermFlag) {
return nil, ErrInvalidPermission{caller.Address, d.Name}
}
// ensure there are enough arguments
if len(args) != d.NArgs*32 {
return nil, fmt.Errorf("%s() takes %d arguments", d.Name)
}
// call the function
return d.F(appState, caller, args, gas)
}
// TODO: catch errors, log em, return 0s to the vm (should some errors cause exceptions though?)
func has_base(appState AppState, caller *Account, args []byte, gas *int64) (output []byte, err error) {
addr, permNum := returnTwoArgs(args)
vmAcc := appState.GetAccount(addr)
if vmAcc == nil {
return nil, fmt.Errorf("Unknown account %X", addr)
}
permN := ptypes.PermFlag(Uint64FromWord256(permNum)) // already shifted
if !ValidPermN(permN) {
return nil, ptypes.ErrInvalidPermission(permN)
}
permInt := byteFromBool(HasPermission(appState, vmAcc, permN))
dbg.Printf("snative.hasBasePerm(0x%X, %b) = %v\n", addr.Postfix(20), permN, permInt)
return LeftPadWord256([]byte{permInt}).Bytes(), nil
}
func set_base(appState AppState, caller *Account, args []byte, gas *int64) (output []byte, err error) {
addr, permNum, perm := returnThreeArgs(args)
vmAcc := appState.GetAccount(addr)
if vmAcc == nil {
return nil, fmt.Errorf("Unknown account %X", addr)
}
permN := ptypes.PermFlag(Uint64FromWord256(permNum))
if !ValidPermN(permN) {
return nil, ptypes.ErrInvalidPermission(permN)
}
permV := !perm.IsZero()
if err = vmAcc.Permissions.Base.Set(permN, permV); err != nil {
return nil, err
}
appState.UpdateAccount(vmAcc)
dbg.Printf("snative.setBasePerm(0x%X, %b, %v)\n", addr.Postfix(20), permN, permV)
return perm.Bytes(), nil
}
func unset_base(appState AppState, caller *Account, args []byte, gas *int64) (output []byte, err error) {
addr, permNum := returnTwoArgs(args)
vmAcc := appState.GetAccount(addr)
if vmAcc == nil {
return nil, fmt.Errorf("Unknown account %X", addr)
}
permN := ptypes.PermFlag(Uint64FromWord256(permNum))
if !ValidPermN(permN) {
return nil, ptypes.ErrInvalidPermission(permN)
}
if err = vmAcc.Permissions.Base.Unset(permN); err != nil {
return nil, err
}
appState.UpdateAccount(vmAcc)
dbg.Printf("snative.unsetBasePerm(0x%X, %b)\n", addr.Postfix(20), permN)
return permNum.Bytes(), nil
}
func set_global(appState AppState, caller *Account, args []byte, gas *int64) (output []byte, err error) {
permNum, perm := returnTwoArgs(args)
vmAcc := appState.GetAccount(ptypes.GlobalPermissionsAddress256)
if vmAcc == nil {
PanicSanity("cant find the global permissions account")
}
permN := ptypes.PermFlag(Uint64FromWord256(permNum))
if !ValidPermN(permN) {
return nil, ptypes.ErrInvalidPermission(permN)
}
permV := !perm.IsZero()
if err = vmAcc.Permissions.Base.Set(permN, permV); err != nil {
return nil, err
}
appState.UpdateAccount(vmAcc)
dbg.Printf("snative.setGlobalPerm(%b, %v)\n", permN, permV)
return perm.Bytes(), nil
}
func has_role(appState AppState, caller *Account, args []byte, gas *int64) (output []byte, err error) {
addr, role := returnTwoArgs(args)
vmAcc := appState.GetAccount(addr)
if vmAcc == nil {
return nil, fmt.Errorf("Unknown account %X", addr)
}
roleS := string(role.Bytes())
permInt := byteFromBool(vmAcc.Permissions.HasRole(roleS))
dbg.Printf("snative.hasRole(0x%X, %s) = %v\n", addr.Postfix(20), roleS, permInt > 0)
return LeftPadWord256([]byte{permInt}).Bytes(), nil
}
func add_role(appState AppState, caller *Account, args []byte, gas *int64) (output []byte, err error) {
addr, role := returnTwoArgs(args)
vmAcc := appState.GetAccount(addr)
if vmAcc == nil {
return nil, fmt.Errorf("Unknown account %X", addr)
}
roleS := string(role.Bytes())
permInt := byteFromBool(vmAcc.Permissions.AddRole(roleS))
appState.UpdateAccount(vmAcc)
dbg.Printf("snative.addRole(0x%X, %s) = %v\n", addr.Postfix(20), roleS, permInt > 0)
return LeftPadWord256([]byte{permInt}).Bytes(), nil
}
func rm_role(appState AppState, caller *Account, args []byte, gas *int64) (output []byte, err error) {
addr, role := returnTwoArgs(args)
vmAcc := appState.GetAccount(addr)
if vmAcc == nil {
return nil, fmt.Errorf("Unknown account %X", addr)
}
roleS := string(role.Bytes())
permInt := byteFromBool(vmAcc.Permissions.RmRole(roleS))
appState.UpdateAccount(vmAcc)
dbg.Printf("snative.rmRole(0x%X, %s) = %v\n", addr.Postfix(20), roleS, permInt > 0)
return LeftPadWord256([]byte{permInt}).Bytes(), nil
}
//------------------------------------------------------------------------------------------------
// Errors and utility funcs
type ErrInvalidPermission struct {
Address Word256
SNative string
}
func (e ErrInvalidPermission) Error() string {
return fmt.Sprintf("Account %X does not have permission snative.%s", e.Address.Postfix(20), e.SNative)
}
// Checks if a permission flag is valid (a known base chain or snative permission)
func ValidPermN(n ptypes.PermFlag) bool {
if n > ptypes.TopPermFlag {
return false
}
return true
}
// CONTRACT: length has already been checked
func returnTwoArgs(args []byte) (a Word256, b Word256) {
copy(a[:], args[:32])
copy(b[:], args[32:64])
return
}
// CONTRACT: length has already been checked
func returnThreeArgs(args []byte) (a Word256, b Word256, c Word256) {
copy(a[:], args[:32])
copy(b[:], args[32:64])
copy(c[:], args[64:96])
return
}
func byteFromBool(b bool) byte {
if b {
return 0x1
}
return 0x0
}