Teach route(8) to run in jails

[nyan_myuji.xyz]

Summary

Add -j <jail> flag to route(8) to allow route to perform actions in
a Jail.

[melifaro]

Thank you for working on this! Conceptually it LGTM, please see a comment on the implementation part.

sbin/route/route.c

237

I'd rather save the parameter here and explicitly call some jail_attach wrapper later. This will help keep argument parsing and business logic split, hopefully maintaining the same level of readability

[nyan_myuji.xyz]

• move jail attach away from arg parse

[nyan_myuji.xyz]

@melifaro Thank you so much for reviewing and the suggestion! I have moved the jail attach bit out and added the missed Makefile changes. (oops)

[melifaro]

sbin/route/route.c

238

Do we need usejail at all?

[crest_freebsd_rlwinm.de]

It reads to me like initialising jail_name to NULL and replacing if (usejail) with if (jail_name != NULL) would make the usejail variable superfluous. Splitting a pointer and its validity into two variables like this (jail_name and usejail) introduces the potential for contradiction if only one of the two is updated. If this split is required for something I would like to see them stored together in a struct { char *, bool } instead of destructured into two variables.

sbin/route/route.c

238

It reads to me like initialising jail_name to NULL and replacing if (usejail) with if (jail_name != NULL) would make the usejail variable superfluous. Splitting a pointer and its validity into two variables like this (jail_name and usejail) introduces the potential for contradiction if only one of the two is updated. If this split is required for something I would like to see them stored together in a struct { char *, bool } instead of destructured into two variables.

[nyan_myuji.xyz]

• remove usejail variable

[crest_freebsd_rlwinm.de]

The jail_name variable must be initialised to NULL. This should be done through an explicit char * jail_name = NULL; in line 101 of route.c.

[nyan_myuji.xyz]

In D40377#922083, @crest_freebsd_rlwinm.de wrote:

The jail_name variable must be initialised to NULL. This should be done through an explicit char * jail_name = NULL; in line 101 of route.c.

Static storage are always initialized to 0/NULL by C standard.

[crest_freebsd_rlwinm.de]

In D40377#922101, @nyan_myuji.xyz wrote:

In D40377#922083, @crest_freebsd_rlwinm.de wrote:

The jail_name variable must be initialised to NULL. This should be done through an explicit char * jail_name = NULL; in line 101 of route.c.

Static storage are always initialized to 0/NULL by C standard.

You're correct. Looking at just the diff again I assumed it was allocated on the stack instead of in the bss section.