Implementation of exec.c for bitcoin

Author: roconnor-blockstream

C/Makefile

@@ -1,5 +1,5 @@
 CORE_OBJS := bitstream.o dag.o deserialize.o eval.o frame.o jets.o jets-secp256k1.o rsort.o sha256.o type.o typeInference.o
-BITCOIN_OBJS := bitcoin/env.o bitcoin/ops.o bitcoin/jets.o bitcoin/primitive.o
+BITCOIN_OBJS := bitcoin/env.o bitcoin/exec.o bitcoin/ops.o bitcoin/jets.o bitcoin/primitive.o
 ELEMENTS_OBJS := elements/env.o elements/exec.o elements/ops.o elements/jets.o elements/primitive.o elements/cmr.o
 TEST_OBJS := test.o ctx8Pruned.o ctx8Unpruned.o hashBlock.o regression4.o schnorr0.o schnorr6.o typeSkipTest.o elements/checkSigHashAllTx1.o
 

C/bitcoin/exec.c

@@ -0,0 +1,125 @@
+#include <simplicity/bitcoin/exec.h>
+
+#include <stdalign.h>
+#include <string.h>
+#include "primitive.h"
+#include "../deserialize.h"
+#include "../eval.h"
+#include "../limitations.h"
+#include "../simplicity_alloc.h"
+#include "../simplicity_assert.h"
+#include "../typeInference.h"
+
+/* Deserialize a Simplicity 'program' with its 'witness' data and execute it in the environment of the 'ix'th input of 'tx' with `taproot`.
+ *
+ * If at any time malloc fails then '*error' is set to 'SIMPLICITY_ERR_MALLOC' and 'false' is returned,
+ * meaning we were unable to determine the result of the simplicity program.
+ * Otherwise, 'true' is returned indicating that the result was successfully computed and returned in the '*error' value.
+ *
+ * If deserialization, analysis, or execution fails, then '*error' is set to some simplicity_err.
+ *
+ * If 'amr != NULL' and the annotated Merkle root of the decoded expression doesn't match 'amr' then '*error' is set to 'SIMPLICITY_ERR_AMR'.
+ *
+ * Otherwise '*error' is set to 'SIMPLICITY_NO_ERROR'.
+ *
+ * If 'ihr != NULL' and '*error' is set to 'SIMPLICITY_NO_ERROR', then the identity hash of the root of the decoded expression is written to 'ihr'.
+ * Otherwise if 'ihr != NULL'  and '*error' is not set to 'SIMPLCITY_NO_ERROR', then 'ihr' may or may not be written to.
+ *
+ * Precondition: NULL != error;
+ *               NULL != ihr implies unsigned char ihr[32]
+ *               NULL != tx;
+ *               NULL != taproot;
+ *               0 <= budget;
+ *               NULL != amr implies unsigned char amr[32]
+ *               unsigned char program[program_len]
+ *               unsigned char witness[witness_len]
+ */
+extern bool simplicity_bitcoin_execSimplicity( simplicity_err* error, unsigned char* ihr
+                                              , const transaction* tx, uint_fast32_t ix, const tapEnv* taproot
+                                              , int64_t budget
+                                              , const unsigned char* amr
+                                              , const unsigned char* program, size_t program_len
+                                              , const unsigned char* witness, size_t witness_len) {
+  simplicity_assert(NULL != error);
+  simplicity_assert(NULL != tx);
+  simplicity_assert(NULL != taproot);
+  simplicity_assert(0 <= budget);
+  simplicity_assert(NULL != program || 0 == program_len);
+  simplicity_assert(NULL != witness || 0 == witness_len);
+
+  combinator_counters census;
+  dag_node* dag = NULL;
+  int_fast32_t dag_len;
+  sha256_midstate amr_hash;
+
+  if (amr) sha256_toMidstate(amr_hash.s, amr);
+
+  {
+    bitstream stream = initializeBitstream(program, program_len);
+    dag_len = simplicity_decodeMallocDag(&dag, simplicity_bitcoin_decodeJet, &census, &stream);
+    if (dag_len <= 0) {
+      simplicity_assert(dag_len < 0);
+      *error = (simplicity_err)dag_len;
+      return IS_PERMANENT(*error);
+    }
+    simplicity_assert(NULL != dag);
+    simplicity_assert((uint_fast32_t)dag_len <= DAG_LEN_MAX);
+    *error = simplicity_closeBitstream(&stream);
+  }
+
+  if (IS_OK(*error)) {
+    if (0 != memcmp(taproot->scriptCMR.s, dag[dag_len-1].cmr.s, sizeof(uint32_t[8]))) {
+      *error = SIMPLICITY_ERR_CMR;
+    }
+  }
+
+  if (IS_OK(*error)) {
+    type* type_dag = NULL;
+    *error = simplicity_mallocTypeInference(&type_dag, simplicity_bitcoin_mallocBoundVars, dag, (uint_fast32_t)dag_len, &census);
+    if (IS_OK(*error)) {
+      simplicity_assert(NULL != type_dag);
+      if (0 != dag[dag_len-1].sourceType || 0 != dag[dag_len-1].targetType) {
+        *error = SIMPLICITY_ERR_TYPE_INFERENCE_NOT_PROGRAM;
+      }
+    }
+    if (IS_OK(*error)) {
+      bitstream witness_stream = initializeBitstream(witness, witness_len);
+      *error = simplicity_fillWitnessData(dag, type_dag, (uint_fast32_t)dag_len, &witness_stream);
+      if (IS_OK(*error)) {
+        *error = simplicity_closeBitstream(&witness_stream);
+        if (SIMPLICITY_ERR_BITSTREAM_TRAILING_BYTES == *error) *error = SIMPLICITY_ERR_WITNESS_TRAILING_BYTES;
+        if (SIMPLICITY_ERR_BITSTREAM_ILLEGAL_PADDING == *error) *error = SIMPLICITY_ERR_WITNESS_ILLEGAL_PADDING;
+      }
+    }
+    if (IS_OK(*error)) {
+      sha256_midstate ihr_buf;
+      *error = simplicity_verifyNoDuplicateIdentityHashes(&ihr_buf, dag, type_dag, (uint_fast32_t)dag_len);
+      if (IS_OK(*error) && ihr) sha256_fromMidstate(ihr, ihr_buf.s);
+    }
+    if (IS_OK(*error) && amr) {
+      static_assert(DAG_LEN_MAX <= SIZE_MAX / sizeof(analyses), "analysis array too large.");
+      static_assert(1 <= DAG_LEN_MAX, "DAG_LEN_MAX is zero.");
+      static_assert(DAG_LEN_MAX - 1 <= UINT32_MAX, "analysis array index does nto fit in uint32_t.");
+      analyses *analysis = simplicity_malloc((size_t)dag_len * sizeof(analyses));
+      if (analysis) {
+        simplicity_computeAnnotatedMerkleRoot(analysis, dag, type_dag, (uint_fast32_t)dag_len);
+        if (0 != memcmp(amr_hash.s, analysis[dag_len-1].annotatedMerkleRoot.s, sizeof(uint32_t[8]))) {
+          *error = SIMPLICITY_ERR_AMR;
+        }
+      } else {
+        /* malloc failed which counts as a transient error. */
+        *error = SIMPLICITY_ERR_MALLOC;
+      }
+      simplicity_free(analysis);
+    }
+    if (IS_OK(*error)) {
+      txEnv env = simplicity_bitcoin_build_txEnv(tx, taproot, ix);
+      static_assert(BUDGET_MAX <= UBOUNDED_MAX, "BUDGET_MAX doesn't fit in ubounded.");
+      *error = evalTCOProgram(dag, type_dag, (size_t)dag_len, &(ubounded){budget <= BUDGET_MAX ? (ubounded)budget : BUDGET_MAX}, &env);
+    }
+    simplicity_free(type_dag);
+  }
+
+  simplicity_free(dag);
+  return IS_PERMANENT(*error);
+}