Having to know structs is not really an issue - you also need to know text formats, JSON schemas, what not.

Re-ordering of structs is always forbidden with the binary format being strictly specified, so there's nothing to worry about there. Can't exactly shuffle bytes in a text format either, and plan9 control strings tend to have positional arguments.

The current structs do leave something to be desired though.

I was quite disappointed by the ABI differences between different architectures when I was doing network transparent uinput.

https://git.cloudef.pw/uinputd.git/tree/common/packet.h#n34 https://git.cloudef.pw/uinputd.git/tree/server/uinputd.c#n16

(Excuse to write code to use my PS Vita as gamepad :D)

If you setup user namespace, the child processes will inherit that namespace. The difference is that plan9 is fully built on this idea and isn't multi-user, on linux you have to opt-in to this. It's very useful and underused (mostly used by containers). I wanted to ship my AWS lambdas this way, but sadly AWS lambdas don't allow user namespaces.

https://github.com/aws/aws-lambda-base-images/issues/143