In unix like user spaces applications have access to a lot of stuff by default (such as the complete filesystem accessible to the executing users and a lot of

In unix like user spaces applications have access to a lot of stuff by default (such as the complete filesystem accessible to the executing users and a lot of system calls). For security purposes tighter restrictions would be better. Pledge() and Unveil() allow application authors to opt in at run time to restrict what they can do in the future.