Is the salary received from working in a library that forges and sells pirated books without the permission of the publishers (non-Muslims) permissible (halal) or forbidden (haram) money, and what is the ruling on the money earned in past years?

It is not permissible to support a library that counterfeits and duplicates books without the permission of their owners, because Allah Almighty says: "And do not cooperate in sin and aggression." If your entire work is in selling and distributing these books, then your salary is an illicit gain and must be given as charity to the poor, the needy, and for the benefit of Muslims, unless you are poor and in need, in which case it is permissible for you to take from it according to your needs. However, if you are wealthy, it is not permissible for you to benefit from it, and you must dispose of it. If you perform other permissible tasks, the ruling depends on the extent of the illicit work. Repentance nullifies what came before it, and Allah forgives all sins.