int NCValidateSegmentPair(uint8_t *mbase_old, uint8_t *mbase_new,
NaClPcAddress vbase, size_t sz,
const NaClCPUFeaturesX86 *features) {
/* TODO(karl): Refactor to use inheritance from NCDecoderStatePair? */
NCDecoderStatePair pair;
NCValidatorState* new_vstate;
NCValidatorState* old_vstate;
int result = 0;
/* Verify that we actually have a segment to walk. */
if (sz == 0) {
printf("VALIDATOR: %"NACL_PRIxNaClPcAddress
": Bad text segment (zero size)\n", vbase);
return 0;
}
old_vstate = NCValidateInit(vbase, sz, FALSE, features);
if (old_vstate != NULL) {
NCValidateDStateInit(old_vstate, mbase_old, vbase, sz);
new_vstate = NCValidateInit(vbase, sz, FALSE, features);
if (new_vstate != NULL) {
NCValidateDStateInit(new_vstate, mbase_new, vbase, sz);
NCDecoderStatePairConstruct(&pair,
&old_vstate->dstate,
&new_vstate->dstate,
NULL); /* copy_func */
pair.action_fn = ValidateInstReplacement;
if (NCDecoderStatePairDecode(&pair)) {
result = 1;
} else {
ValidatePrintOffsetError(0, "Replacement not applied!\n", new_vstate);
}
if (NCValidateFinish(new_vstate)) {
/* Errors occurred during validation. */
result = 0;
}
NCDecoderStatePairDestruct(&pair);
NCDecoderStateDestruct(&new_vstate->dstate);
NCValidateFreeState(&new_vstate);
}
NCDecoderStateDestruct(&old_vstate->dstate);
NCValidateFreeState(&old_vstate);
}
return result;
}
/* Copies code from src to dest in a thread safe way, returns 1 on success,
* returns 0 on error. This will likely assert on error to avoid partially
* copied code or undefined state.
*/
static int NCCopyCode(uint8_t *dst, uint8_t *src, NaClPcAddress vbase,
size_t sz, NaClCopyInstructionFunc copy_func) {
NCDecoderState dst_dstate;
NCDecoderInst dst_inst;
NCDecoderState src_dstate;
NCDecoderInst src_inst;
NCDecoderStatePair pair;
int result = 0;
NCDecoderStateConstruct(&dst_dstate, dst, vbase, sz, &dst_inst, 1);
NCDecoderStateConstruct(&src_dstate, src, vbase, sz, &src_inst, 1);
NCDecoderStatePairConstruct(&pair, &dst_dstate, &src_dstate, copy_func);
pair.action_fn = CopyInstruction;
if (NCDecoderStatePairDecode(&pair)) result = 1;
NCDecoderStatePairDestruct(&pair);
NCDecoderStateDestruct(&src_dstate);
NCDecoderStateDestruct(&dst_dstate);
return result;
}