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Implemented script up to signature checking operators
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@MatthewLM
MatthewLM committed May 23, 2012
1 parent 88deebf commit a66e086
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Showing 3 changed files with 428 additions and 50 deletions.
252 changes: 222 additions & 30 deletions cbitcoin/src/structures/CBScript/CBScript.c
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Expand Up @@ -47,7 +47,7 @@ CBScriptVT * CBCreateScriptVT(){
void CBSetScriptVT(CBScriptVT * VT){
CBSetObjectVT((CBObjectVT *)VT);
((CBObjectVT *)VT)->free = (void (*)(void *))CBFreeScript;
VT->execute = (bool (*)(void *, CBScriptStack *))CBScriptExecute;
VT->execute = (bool (*)(void *, CBScriptStack *,CBDependencies *))CBScriptExecute;
}

// Virtual Table Getter
Expand Down Expand Up @@ -92,9 +92,8 @@ void CBFreeProcessScript(CBScript * self){
// Functions

void CBFreeScriptStack(CBScriptStack stack){
for (int x = 0; x < stack.length; x++) {
for (int x = 0; x < stack.length; x++)
free(stack.elements[x].data);
}
free(stack.elements);
}
CBScriptStack CBNewEmptyScriptStack(){
Expand All @@ -103,18 +102,8 @@ CBScriptStack CBNewEmptyScriptStack(){
stack.length = 0;
return stack;
}
bool CBScriptStackEvalBool(CBScriptStack * stack){
CBScriptStackItem item = stack->elements[stack->length-1];
for (u_int16_t x = 0; x < item.length; x++)
if (item.data[x] != 0)
// Can be negative zero
if (x == item.length - 1 && item.data[x] == 0x80)
return false;
else
return true;
return false;
}
bool CBScriptExecute(CBScript * self,CBScriptStack * stack){
bool CBScriptExecute(CBScript * self,CBScriptStack * stack,CBDependencies * dependencies){
// This looks confusing but isn't too bad, trust me.
CBScriptStack altStack = CBNewEmptyScriptStack();
u_int16_t skipIfElseBlock = 0xffff; // Skips all instructions on or over this if/else level.
u_int16_t ifElseSize = 0; // Amount of if/else block levels
Expand Down Expand Up @@ -200,13 +189,15 @@ bool CBScriptExecute(CBScript * self,CBScriptStack * stack){
CBScriptStackPushItem(stack, item);
}else if (byte == CB_SCRIPT_OP_NOP){
// Nothing...
}else if (byte == CB_SCRIPT_OP_IF || byte == CB_SCRIPT_OP_NOTIF){
}else if (byte == CB_SCRIPT_OP_IF
|| byte == CB_SCRIPT_OP_NOTIF){
// If top of stack is true, continue, else goto OP_ELSE or OP_ENDIF.
ifElseSize++;
if (!stack->length)
return false; // Stack empty
bool res = CBScriptStackEvalBool(stack);
if ((res && byte == CB_SCRIPT_OP_IF) || (!res && byte == CB_SCRIPT_OP_NOTIF))
if ((res && byte == CB_SCRIPT_OP_IF)
|| (!res && byte == CB_SCRIPT_OP_NOTIF))
skipIfElseBlock = 0xffff;
else
skipIfElseBlock = ifElseSize; // Is skipping on this level until OP_ELSE or OP_ENDIF is reached on this level
Expand Down Expand Up @@ -376,11 +367,12 @@ bool CBScriptExecute(CBScript * self,CBScriptStack * stack){
item.data[0] = len;
}
CBScriptStackPushItem(stack, item);
}else if (byte == CB_SCRIPT_OP_EQUAL || byte == CB_SCRIPT_OP_EQUALVERIFY){
}else if (byte == CB_SCRIPT_OP_EQUAL
|| byte == CB_SCRIPT_OP_EQUALVERIFY){
if (stack->length < 2)
return false; // Stack needs 2 or more elements.
CBScriptStackItem i1 = stack->elements[stack->length-1];
CBScriptStackItem i2 = stack->elements[stack->length-2];
CBScriptStackItem i1 = CBScriptStackPopItem(stack);
CBScriptStackItem i2 = CBScriptStackPopItem(stack);
bool ok = true;
if (i1.length != i2.length)
ok = false;
Expand All @@ -389,17 +381,168 @@ bool CBScriptExecute(CBScript * self,CBScriptStack * stack){
ok = false;
break;
}
// Push result onto stack
CBScriptStackItem item;
item.data = malloc(1);
item.length = 1;
item.data[0] = ok;
CBScriptStackPushItem(stack, item);
if (byte == CB_SCRIPT_OP_EQUALVERIFY)
if (ok)
CBScriptStackRemoveItem(stack);
else
if (byte == CB_SCRIPT_OP_EQUALVERIFY){
if (!ok)
return false; // Failed verification
}else{
// Push result onto stack
CBScriptStackItem item;
item.data = malloc(1);
item.length = 1;
item.data[0] = ok;
CBScriptStackPushItem(stack, item);
}
}else if (byte == CB_SCRIPT_OP_1ADD
|| byte == CB_SCRIPT_OP_1SUB){
if (!stack->length)
return false; // Stack empty
CBScriptStackItem item = stack->elements[stack->length-1];
if (item.length > 4)
return false; // Protocol does not except integers more than 32 bits.
// Convert to 64 bit integer.
int64_t res = CBScriptStackItemToInt64(item);
switch (byte) {
case CB_SCRIPT_OP_1ADD: res++; break;
case CB_SCRIPT_OP_1SUB: res--; break;
}
// Convert back to bitcoin format. Re-assign item as length may have changed.
stack->elements[stack->length-1] = CBInt64ToScriptStackItem(item, res);
}else if (byte == CB_SCRIPT_OP_NEGATE){
if (!stack->length)
return false; // Stack empty
CBScriptStackItem item = stack->elements[stack->length-1];
if (item.length > 4)
return false; // Protocol does not except integers more than 32 bits.
item.data[item.length-1] ^= 0x80; // Toggles most significant bit.
}else if (byte == CB_SCRIPT_OP_ABS){
if (!stack->length)
return false; // Stack empty
CBScriptStackItem item = stack->elements[stack->length-1];
if (item.length > 4)
return false; // Protocol does not except integers more than 32 bits.
item.data[item.length-1] |= 0x80; // Sets most significant bit.
}else if (byte == CB_SCRIPT_OP_NOT
|| byte == CB_SCRIPT_OP_0NOTEQUAL){
if (!stack->length)
return false; // Stack empty
CBScriptStackItem item = stack->elements[stack->length-1];
bool res = CBScriptStackEvalBool(stack);
item.length = 1;
item.data = realloc(item.data, 1);
if (byte == CB_SCRIPT_OP_NOT)
item.data[0] = !res;
else
item.data[0] = res;
stack->elements[stack->length-1] = item; // Length modification
}else if (byte == CB_SCRIPT_OP_ADD
|| byte == CB_SCRIPT_OP_SUB
|| byte == CB_SCRIPT_OP_NUMEQUAL
|| byte == CB_SCRIPT_OP_NUMNOTEQUAL
|| byte == CB_SCRIPT_OP_NUMEQUALVERIFY
|| byte == CB_SCRIPT_OP_LESSTHAN
|| byte == CB_SCRIPT_OP_LESSTHANOREQUAL
|| byte == CB_SCRIPT_OP_GREATERTHAN
|| byte == CB_SCRIPT_OP_GREATERTHANOREQUAL
|| byte == CB_SCRIPT_OP_MIN
|| byte == CB_SCRIPT_OP_MAX){
if (stack->length < 2)
return false; // Stack needs 2 or more elements.
// Take top two items, removing the top one. First on which is two down will be assigned the result.
CBScriptStackItem i1 = stack->elements[stack->length-2];
CBScriptStackItem i2 = CBScriptStackPopItem(stack);
if (i1.length > 4 || i2.length > 4)
return false; // Protocol does not except integers more than 32 bits.
int64_t res = CBScriptStackItemToInt64(i1);
int64_t second = CBScriptStackItemToInt64(i2);
free(i2.data); // No longer need i2
switch (byte) {
case CB_SCRIPT_OP_ADD: res += second; break;
case CB_SCRIPT_OP_SUB: res -= second; break;
case CB_SCRIPT_OP_NUMEQUALVERIFY:
case CB_SCRIPT_OP_NUMEQUAL: res = (res == second); break;
case CB_SCRIPT_OP_NUMNOTEQUAL: res = (res != second); break;
case CB_SCRIPT_OP_LESSTHAN: res = (res < second); break;
case CB_SCRIPT_OP_LESSTHANOREQUAL: res = (res <= second); break;
case CB_SCRIPT_OP_GREATERTHAN: res = (res > second); break;
case CB_SCRIPT_OP_GREATERTHANOREQUAL: res = (res >= second); break;
case CB_SCRIPT_OP_MIN: res = (res > second)? second : res; break;
case CB_SCRIPT_OP_MAX: res = (res < second)? second : res; break;
}
if (byte == CB_SCRIPT_OP_NUMEQUALVERIFY){
if (!res)
return false;
CBScriptStackRemoveItem(stack); // Remove top item that will not hold the rest as this is OP_NUMEQUALVERIFY
}else
// Convert back to bitcoin format. Re-assign item as length may have changed. i1 now goes on top.
stack->elements[stack->length-1] = CBInt64ToScriptStackItem(i1, res);
}else if (byte == CB_SCRIPT_OP_BOOLAND
|| byte == CB_SCRIPT_OP_BOOLOR){
if (stack->length < 2)
return false; // Stack needs 2 or more elements
// Take top two items, removing the top one. First on which is two down will be assigned the result.
CBScriptStackItem i1 = stack->elements[stack->length-2];
bool i2bool = CBScriptStackEvalBool(stack);
CBScriptStackItem i2 = CBScriptStackPopItem(stack);
bool i1bool = CBScriptStackEvalBool(stack);
if (i1.length > 4 || i2.length > 4)
return false; // Protocol does not except integers more than 32 bits.
free(i2.data); // No longer need i2.
i1.length = 1;
i1.data = realloc(i1.data, 1);
i1.data[0] = (byte == CB_SCRIPT_OP_BOOLAND)? i1bool && i2bool : i1bool || i2bool;
stack->elements[stack->length-1] = i1;
}else if (byte == CB_SCRIPT_OP_WITHIN){
if (stack->length < 3)
return false; // Stack needs 3 or more elements
CBScriptStackItem item = stack->elements[stack->length-3];
CBScriptStackItem top = CBScriptStackPopItem(stack);
CBScriptStackItem bottom = CBScriptStackPopItem(stack);
if (item.length > 4 || top.length > 4 || bottom.length > 4)
return false; // Protocol does not except integers more than 32 bits.
int64_t res = CBScriptStackItemToInt64(item);
int64_t topi = CBScriptStackItemToInt64(top);
free(top.data); // No longer need top.
int64_t bottomi = CBScriptStackItemToInt64(bottom);
free(bottom.data); // No longer need bottom.
item.length = 1;
item.data = realloc(item.data, 1);
item.data[0] = bottomi <= res && res < topi;
stack->elements[stack->length-1] = item;
}else if (byte == CB_SCRIPT_OP_RIPEMD160
|| byte == CB_SCRIPT_OP_SHA1
|| byte == CB_SCRIPT_OP_HASH160
|| byte == CB_SCRIPT_OP_SHA256
|| byte == CB_SCRIPT_OP_HASH256){
CBScriptStackItem item = stack->elements[stack->length-1];
u_int8_t * data;
u_int8_t * data2;
switch (byte) {
case CB_SCRIPT_OP_RIPEMD160: data = dependencies->ripemd160(item.data,item.length); break;
case CB_SCRIPT_OP_SHA1: data = dependencies->sha1(item.data,item.length); break;
case CB_SCRIPT_OP_HASH160:
data2 = dependencies->sha256(item.data,item.length);
data = dependencies->ripemd160(data2,32);
free(data2);
break;
case CB_SCRIPT_OP_SHA256: data = dependencies->sha256(item.data,item.length); break;
case CB_SCRIPT_OP_HASH256:
data2 = dependencies->sha256(item.data,item.length);
data = dependencies->sha256(data2,32);
free(data2);
break;
}
free(item.data);
item.data = data;
item.length = (byte == CB_SCRIPT_OP_SHA256 || byte == CB_SCRIPT_OP_HASH256)? 32 : 20;
stack->elements[stack->length-1] = item;
}else if (byte == CB_SCRIPT_OP_CODESEPARATOR){

}else if (byte == CB_SCRIPT_OP_CHECKSIG
|| byte == CB_SCRIPT_OP_CHECKSIGVERIFY){

}else if (byte == CB_SCRIPT_OP_CHECKMULTISIG
|| byte == CB_SCRIPT_OP_CHECKMULTISIGVERIFY){

}
}
}
Expand All @@ -423,6 +566,28 @@ CBScriptStackItem CBScriptStackCopyItem(CBScriptStack * stack,u_int8_t fromTop){
memmove(newItem.data, oldItem.data, newItem.length);
return newItem;
}
bool CBScriptStackEvalBool(CBScriptStack * stack){
CBScriptStackItem item = stack->elements[stack->length-1];
for (u_int16_t x = 0; x < item.length; x++)
if (item.data[x] != 0)
// Can be negative zero
if (x == item.length - 1 && item.data[x] == 0x80)
return false;
else
return true;
return false;
}
int64_t CBScriptStackItemToInt64(CBScriptStackItem item){
int64_t res = item.data[0]; // May overflow 32 bits
for (u_int8_t x = 1; x < item.length; x++)
res |= item.data[x] << (8*x);
if ((res >> (8*(item.length-1))) > 0x7F) { // Negative
// Convert signage for int64_t
res ^= 0x80 << (8*(item.length-1)); // Removed sign bit.
res = -res;
}
return res;
}
CBScriptStackItem CBScriptStackPopItem(CBScriptStack * stack){
stack->length--;
CBScriptStackItem item = stack->elements[stack->length];
Expand All @@ -439,3 +604,30 @@ void CBScriptStackRemoveItem(CBScriptStack * stack){
free(stack->elements[stack->length].data);
stack->elements = realloc(stack->elements, sizeof(*stack->elements)*stack->length);
}
CBScriptStackItem CBInt64ToScriptStackItem(CBScriptStackItem item,int64_t i){
u_int64_t ui = (i < 0)? -i : i;
// Discover length
for (u_int8_t x = 7;; x--) {
u_int8_t b = ui >> (8*x);
if(b){
item.length = x + 1;
// If byte over 0x7F add extra byte
if (b > 0x7F)
item.length++;
item.data = realloc(item.data, item.length);
break;
}
if(!x)
break;
}
// Add data
for (u_int8_t x = 0; x < item.length; x++)
if (x == 8)
item.data[8] = 0; // Extra byte overflowing 8 bytes
else
item.data[x] = ui >> (8*x);
// Add sign
if (i < 0)
item.data[item.length-1] ^= 0x80;
return item;
}
31 changes: 23 additions & 8 deletions cbitcoin/src/structures/CBScript/CBScript.h
View file
Expand Up @@ -32,6 +32,7 @@

#include "CBByteArray.h"
#include "CBNetworkParameters.h"
#include "CBDependencies.h"
#include <stdbool.h>

/**
Expand All @@ -57,7 +58,7 @@ typedef struct{
*/
typedef struct{
CBObjectVT base; /**< CBObjectVT base structure */
bool (*execute)(void *,CBScriptStack *); /**< Executes the script with the given stack. */
bool (*execute)(void *,CBScriptStack *,CBDependencies *); /**< Executes the script with the given stack and dependencies structure. */
}CBScriptVT;

/**
Expand Down Expand Up @@ -133,26 +134,33 @@ void CBFreeScriptStack(CBScriptStack stack);
@returns The new empty stack.
*/
CBScriptStack CBNewEmptyScriptStack(void);
/**
@brief Evaluates the top stack item as a bool. False if 0 or -0.
@param stack The stack.
@returns The boolean result.
*/
bool CBScriptStackEvalBool(CBScriptStack * stack);
/**
@brief Executes a bitcoin script.
@param self The CBScript object with the program
@param stack A pointer to the input stack for the program.
@param dependencies A pointer to a CBDependencies structure object.
@returns True is the program ended with true, false otherwise or on script failure.
*/
bool CBScriptExecute(CBScript * self,CBScriptStack * stack);
bool CBScriptExecute(CBScript * self,CBScriptStack * stack,CBDependencies * dependencies);
/**
@brief Returns a copy of a stack item, "fromTop" from the top.
@param stack A pointer to the stack.
@param fromTop Number of items from the top to copy.
@returns A copy of the stack item which should be freed.
*/
CBScriptStackItem CBScriptStackCopyItem(CBScriptStack * stack,u_int8_t fromTop);
/**
@brief Evaluates the top stack item as a bool. False if 0 or -0.
@param stack The stack.
@returns The boolean result.
*/
bool CBScriptStackEvalBool(CBScriptStack * stack);
/**
@brief Converts a CBScriptStackItem to an int64_t
@param item The CBScriptStackItem to convert
@returns A 64 bit signed integer.
*/
int64_t CBScriptStackItemToInt64(CBScriptStackItem item);
/**
@brief Removes the top item from the stack and returns it.
@param stack A pointer to the stack to pop the data.
Expand All @@ -170,5 +178,12 @@ void CBScriptStackPushItem(CBScriptStack * stack,CBScriptStackItem item);
@param stack A pointer to the stack to remove the data.
*/
void CBScriptStackRemoveItem(CBScriptStack * stack);
/**
@brief Converts a int64_t to a CBScriptStackItem
@param item Pass in a CBScriptStackItem for reallocating data.
@param i The 64 bit signed integer.
@returns A CBScriptStackItem.
*/
CBScriptStackItem CBInt64ToScriptStackItem(CBScriptStackItem item,int64_t i);

#endif

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