syscalls. (strictly speaking, it breaks abi. i don't think it's a problem
because this feature is short-lived and there are no affected in-tree
filesystems.)
signal handler, by deriving the context pointer from the stack pointer
instead of trying to read it from where the sigaction function may have
overwritten it with arbitrary bits.
Fix provided by Matthias Drochner in the PR.
introduce fileassoc(9), a kernel interface for associating meta-data with
files using in-kernel memory. this is very similar to what we had in
veriexec till now, only abstracted so it can be used more easily by more
consumers.
this also prompted the redesign of the interface, making it work on vnodes
and mounts and not directly on devices and inodes. internally, we still
use file-id but that's gonna change soon... the interface will remain
consistent.
as a result, veriexec went under some heavy changes to conform to the new
interface. since we no longer use device numbers to identify file-systems,
the veriexec sysctl stuff changed too: kern.veriexec.count.dev_N is now
kern.veriexec.tableN.* where 'N' is NOT the device number but rather a
way to distinguish several mounts.
also worth noting is the plugging of unmount/delete operations
wrt/fileassoc and veriexec.
tons of input from yamt@, wrstuden@, martin@, and christos@.
While touching all vptofh/fhtovp functions, get rid of VFS_MAXFIDSIZ,
version the getfh(2) syscall and explicitly pass the size available in
the filehandle from userland.
Discussed on tech-kern, with lots of help from yamt (thanks!).
