Scott Cheloha <[email protected]> wrote: > The badsys() function has been here since import. Its comment > indicates that SIGSYS might arrive if the system doesn't support > sysctl, which is not applicable to us anymore, if ever. > > The only legitimate case I can think of here, now, is the desire > to support dropping an old init(8) onto a new kernel and not having > the box panic immediately if it calls an obsolete syscall. > > But that isn't something we support, no? And if the kernel ABI is > changing such that init(8) is calling an obsolete syscall, there are > steps one can take to migrate init(8) to the new ABI to prevent the > situation. > > So SIGSYS should cause a disaster() exit upon first receipt like > all the other signals we haven't defined behavior for.
Back in the old days (before horses had horseshoes), upgrades with bsd.rd or other hot-plug media were far from trivial. If the ABI changed, you wanted init to "limp" towards starting a single-user shell at least, otherwise you were prevented from next steps towards crossing the ABI bump by replacing init... I can see your argument that this isn't needed anymore.
