I learned a great deal about designing understandable, secure, reliable systems from studying the design of qmail.
What a fantastic modular design… worth study!
slide 18: that’s not what “no parsing required” means.
split(0) and “find the appropriate T” is parsing, giving qmail-rspawn a byte offset into the file is what i would call “not parsing”
In context, it means not parsing RFC 754 / 822 / any of those things that you really don’t want to deal with in this part of the system, but could end up sticking yourself with if you’re not careful. What it’s doing is trivial by comparison.