with privilege elevation no suid or sgid binaries are necessary any
longer. Applications can be executed completely unprivileged. Systrace
raises the privileges for a single system call depending on the
configured policy.
Idea from discussions with Perry Metzger, Dug Song and Marcus Watts.
Approved by christos and thorpej.
- avoid race conditions by having seqno in ioctl
- better uid/gid tracking
- "replace" policy to replace args
- less diffs, as many of local changes were fed back to openbsd already
due to the 1st item, it was impossible for us to provide backward-compatibility
(new kernel + old bin/systrace won't work). upgrade both.
