macOS Daemonology: Communicate with Daemons, Agents, and Helpers Through Xpc

Volodymyr Vashurkin (@alkenso) is an experienced macOS system and security developer and engineer. His first steps in daemonology were made while researching FileVault full disk encryption on macOS, and its interaction with iCloud services. iCloud on macOS uses plenty of system daemons and user agents, and investigating macOS's infrastructure led to a solid understanding of how the background world of macOS works. This led him deeply into the development of security solutions for macOS. Working in the security area, Volodymyr gained practical skills for creating GUI-based applications with fewer user agents (user background processes) and root daemons (root'ed background processes). In developing his knowledge and skills, Volodymyr faced numerous tricky cases, lack of documentation, and minor and major documentation gaffes. He would like to help his readers avoid the same pitfalls.