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Don't crash while reporting a bad liveness value #27

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Don't crash while reporting a bad liveness value #27

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25 changes: 19 additions & 6 deletions src/liveness.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -179,6 +179,14 @@ namespace {
// custom_types::logger.debug("Complete Liveness::FromStatics");
// }

// The value we are reporting on is, by definition, one whose class pointer we
// already suspect. Dereferencing it is what turns this diagnostic into a
// SIGSEGV instead of a log message. A real Il2CppClass points its klass field
// back at itself and has a name.
static inline bool LooksLikeValidClass(Il2CppClass const* klass) {
return klass != nullptr && klass->klass == klass && klass->name != nullptr;
}

static inline bool HasParentUnsafe(Il2CppClass const* klass, Il2CppClass const* parent) {
return klass->typeHierarchyDepth >= parent->typeHierarchyDepth && klass->typeHierarchy[parent->typeHierarchyDepth - 1] == parent;
}
Expand Down Expand Up @@ -311,14 +319,19 @@ namespace {
custom_types::logAll(GET_CLASS(obj));
}
custom_types::logger.critical("KLASS PTR: {}", fmt::ptr(val->klass));
if (filterClass) {
custom_types::logger.critical("Attempting HasParentUnsafe({}, {})...", fmt::ptr(GET_CLASS(val)), fmt::ptr(filterClass));
auto ret = HasParentUnsafe(GET_CLASS(val), filterClass);
custom_types::logger.critical("HasParentUnsafe return: {}", ret);
}
if (GET_CLASS(val)) {
if (LooksLikeValidClass(GET_CLASS(val))) {
if (LooksLikeValidClass(filterClass)) {
custom_types::logger.critical("Attempting HasParentUnsafe({}, {})...", fmt::ptr(GET_CLASS(val)), fmt::ptr(filterClass));
auto ret = HasParentUnsafe(GET_CLASS(val), filterClass);
custom_types::logger.critical("HasParentUnsafe return: {}", ret);
} else {
custom_types::logger.critical("Filter class {} is not a valid Il2CppClass, skipping HasParentUnsafe", fmt::ptr(filterClass));
}
custom_types::logAll(GET_CLASS(val));
} else {
custom_types::logger.critical("Class {} of the offending instance is not a valid Il2CppClass, skipping the parent check and class dump", fmt::ptr(GET_CLASS(val)));
}
custom_types::logger.critical("Continuing without crashing");
// Things I have learned, just dumping here:
// static fields and classes that have a nonzero quantity of static
// fields need to be added to: Class::GetStaticFieldData() as for
Expand Down