getting types of function arguments in Interceptor hooks

[chib0]

the only way I can find to get the types of arguments to functions in hooks (or from the function signature in general) is using the argumentTypes property.

this property strips away reader and writer information leaving you only with the type of data, namely 'pointer', 'boolean' etc.

while this works find for basic types, it inhibits deep inspection of objects, since all pointer types get the type of 'pointer':
an Object (encoded as @) is a pointer.
a char * (encoded *) is a pointer.
a block (@?) is also just a pointer.

the information is ready and used while parsing the function signature and reading the arguments, it would be great if it could be exposed through argumentTypes as well.

[s1341]

Hit the wrong button there. Sorry.

[chib0]

No worries.
I can close the issue and open a pull request instead, let's just see if my way of solving this is acceptable.
I'm thinking of exposing a new 'argReader' property for methodInvocationWrapper ( which is what I believe is returned from ObjC.classes.someclass['<selector>'] )

This property will expose reader(index) and typeName(index) that return a c'tor function and the true parsed type name respectively.

I would rather not override the original argTypes so I don't break existing code.

[oleavr]

(Sorry for the delay here.)

How about something like obj.method.argumentTypes.toObjC(), which returns an array? We already expose types, so it would be a chopped up version of that, with stack frame offsets omitted.

[oleavr]

(But we should ideally wait until @gebing's TypeScript porting efforts are complete.)

[gebing]

I think the convert between native and javascript is also very useful for processing native export functions, so in my utility code, i ported the toNative and fromNative from frida-objc-bridge to a more universal version, and i also made some utility functions converting between ObjC's NSString/NSArray/NSDictionary and Javascript's string/array/class.

@oleavr
Do you think whether we should change frida like this?