Commit Graph

2 Commits

Author SHA1 Message Date
Warner Losh
f86e60008b Regularize my copyright notice
o Remove All Rights Reserved from my notices
o imp@FreeBSD.org everywhere
o regularize punctiation, eliminate date ranges
o Make sure that it's clear that I don't claim All Rights reserved by listing
  All Rights Reserved on same line as other copyright holders (but not
  me). Other such holders are also listed last where it's clear.
2019-12-04 16:56:11 +00:00
Warner Losh
5ab191c42b Forward compatibility for ino64.
Add forward compatibility so that new binaries can run on old
kernels. If the new system call from ino64 isn't available on your
system, then the old one will be used and the results translated.  The
stat and statfs families of functions are fully emulated. While not
required by policy, in this case it is helpful to our users to provide
this compatibility. In this case, it allows rollback of the kernel
after installing a new userland should a problem be discovered. It
also prevents foot-shooting if a user does an install before rebooting
with the new kernel. Finally, it allows the use case where one needs
to run new binaries on an old kernel as part of an upgrade process.

The getdirentries family uses tricks that may not work on remote
filesystems. Specifically, it uses a buffer 1/4 the size requested to
get the data from he old syscall.

The code carefully uses direct syscalls for old system calls to avoid
referencing freebsd11_* symbols, which contaminate ld-elf.so.1's
export table due to its use of stat functions, which causes errno to
be incorrect in client programs due to the wrong *stat* function being
resolved in some cases.

This code should removed sometime after 12 is branched.

Tested on: 12-current binaries on a 10.3-beta kernel run and return
       consistent results. 12-current kernel and userland with
       packages from before ino64 was committed also work.

Differential Revision: https://reviews.freebsd.org/D11185
Reviewed by: kib@, emaste@
2017-06-23 18:06:20 +00:00