(a) Except as qualified by Subsections (b) and (c), conduct is justified if the actor reasonably believes the conduct is required or authorized by law, by the judgment or order of a competent court or other governmental tribunal, or in the execution of legal process.
(b) The other sections of this chapter control when force is used against a person to protect persons (Subchapter C), to protect property (Subchapter D), for law enforcement (Subchapter E), or by virtue of a special relationship (Subchapter F).
(c) The use of deadly force is not justified under this section unless the actor reasonably believes the deadly force is specifically required by statute or unless it occurs in the lawful conduct of war. If deadly force is so justified, there is no duty to retreat before using it.
(d) The justification afforded by this section is available if the actor reasonably believes:
(1) the court or governmental tribunal has jurisdiction or the process is lawful, even though the court or governmental tribunal lacks jurisdiction or the process is unlawful; or
(2) his conduct is required or authorized to assist a public servant in the performance of his official duty, even though the servant exceeds his lawful authority.