how to retrieve the product or library that a particular user is part of ??

is there any api method to retrieve the product or library under which a user is part of ?

for example consider , we have 2 products under an organization . a and b . a has 2 users x,y b has users x,z

for a user x i should be able to retrieve the product he is part of , ie product a and b

for user y , he is part of product a

similarly for user z , he is part of product b