Its marijuana, looks sativa or sativa dom. Other than that you will never know and either will anyone else, just too many strains around to tell from leaf and usually even from the flower.
Its nearly impossible to identify a strain when its flowering, no way to know at this age. It does look mostly sativa, but if you dont know where it came from or its out of a bag, most likely it was a no name to begin with.
Schwag is not a strain, it's a description of the quality, you can take the best strain in the world and grow it into a bunch of schwag, you can take a seed from a bunch of schwag and it could be one of the better plants out there.