sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

Rework how shared page related data is stored

Store the shared page address in struct vmspace.
Also instead of storing absolute addresses of various shared page
segments save their offsets with respect to the shared page address.
This will be more useful when the shared page address is randomized.

Approved by: mw(mentor)
Sponsored by: Stormshield
Obtained from: Semihalf
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D35393

Introduce the PROC_SIGCODE() macro

Use a getter macro instead of fetching the sigcode address directly
from a sysent of a given process. It assumes that the sigcode is stored
in the shared page, which is true in all cases, except for a.out
binaries. This will be later useful when the shared page address
randomization is introduced.
No functional change intended.

Approved by: mw(mentor)
Sponsored by: Stormshield
Obtained from: Semihalf
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D35392

exec: Reimplement stack address randomization

The approach taken by the stack gap implementation was to insert a
random gap between the top of the fixed stack mapping and the true top
of the main process stack. This approach was chosen so as to avoid
randomizing the previously fixed address of certain process metadata
stored at the top of the stack, but had some shortcomings. In
particular, mlockall(2) calls would wire the gap, bloating the process'
memory usage, and RLIMIT_STACK included the size of the gap so small
(< several MB) limits could not be used.

There is little value in storing each process' ps_strings at a fixed
location, as only very old programs hard-code this address; consumers
were converted decades ago to use a sysctl-based interface for this
purpose. Thus, this change re-implements stack address randomization by
simply breaking the convention of storing ps_strings at a fixed
location, and randomizing the location of the entire stack mapping.
This implementation is simpler and avoids the problems mentioned above,
while being unlikely to break compatibility anywhere the default ASLR
settings are used.

The kern.elfN.aslr.stack_gap sysctl is renamed to kern.elfN.aslr.stack,
and is re-enabled by default.

PR: 260303
Reviewed by: kib
Discussed with: emaste, mw
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33704

exec: Introduce the PROC_PS_STRINGS() macro

Rather than fetching the ps_strings address directly from a process'
sysentvec, use this macro. With stack address randomization the
ps_strings address is no longer fixed.

Reviewed by: kib
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33704

Refactor core dumping code a bit

This makes it possible to use core_write(), core_output(),
and sbuf_drain_core_output(), in Linux coredump code. Moving
them out of imgact_elf.c is necessary because of the weird way
it's being built.

Reviewed By: kib
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D30369

Remove SPARE_USRSPACE.

This constant was used to reserve space at the top of the stack to
hold translated system call arguments for non-default ABIs (the
"stackgap"). However, none of the compatibility ABIs have used the
stackgap in many years and the last use of SPARE_USRSPACE was removed
in r355373.

Reviewed by: kib
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D22697

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

exec.h: Move PS_STRINGS define to kernel-only section

The kern.ps_strings sysctl was introduced in r103767 and the last
use of PS_STRINGS in userspace code was removed in r297888.

PR: 208760 [exp-run]
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5933

Fix core corruption caused by race in note_procstat_vmmap

This fix is spiritually similar to r287442 and was discovered thanks to
the KASSERT added in that revision.

NT_PROCSTAT_VMMAP output length, when packing kinfo structs, is tied to
the length of filenames corresponding to vnodes in the process' vm map
via vn_fullpath. As vnodes may move during coredump, this is racy.

We do not remove the race, only prevent it from causing coredump
corruption.

- Add a sysctl, kern.coredump_pack_vmmapinfo, to allow users to disable
kinfo packing for PROCSTAT_VMMAP notes. This avoids VMMAP corruption
and truncation, even if names change, at the cost of up to PATH_MAX
bytes per mapped object. The new sysctl is documented in core.5.

- Fix note_procstat_vmmap to self-limit in the second pass. This
addresses corruption, at the cost of sometimes producing a truncated
result.

- Fix PROCSTAT_VMMAP consumers libutil (and libprocstat, via copy-paste)
to grok the new zero padding.

Reported by: pho (https://people.freebsd.org/~pho/stress/log/datamove4-2.txt)
Relnotes: yes
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3824

Follow-up to r287442: Move sysctl to compiled-once file

Avoid duplicate sysctl nodes.

Found by: tijl
Approved by: markj (mentor)
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3586

Update the comments in exec.h with help from jilles.

PR: 180970
Submitted by: Carlos Jacobo Puga Medina <cjpugmed@gmail.com>
Reviewed by: jilles
MFC after: 1 week

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Add macro DECLARE_MODULE_TIED to denote a module as requiring the
kernel of exactly the same __FreeBSD_version as the headers module was
compiled against.

Mark our in-tree ABI emulators with DECLARE_MODULE_TIED. The modules
use kernel interfaces that the Release Engineering Team feel are not
stable enough to guarantee they will not change during the life cycle
of a STABLE branch. In particular, the layout of struct sysentvec is
declared to be not part of the STABLE KBI.

Discussed with: bz, rwatson
Approved by: re (bz, kensmith)
MFC after: 2 weeks

- Import the HEAD csup code which is the basis for the cvsmode work.

Make ps_nargvstr and ps_nenvstr unsigned. This fixes an input
validation error in procfs/linprocfs that can be exploited by local
users to cause a kernel panic. All versions of FreeBSD with the patch
referenced in SA-04:17.procfs have this bug, but versions without that
patch have a more serious bug instead. This problem only affects
systems on which procfs or linprocfs is mounted.

Found by: Coverity Prevent analysis tool
Security: Local DOS

Do a pass over all modules in the kernel and make them return EOPNOTSUPP
for unknown events.

A number of modules return EINVAL in this instance, and I have left
those alone for now and instead taught MOD_QUIESCE to accept this
as "didn't do anything".

Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core

Increase the size of SPARE_USRSPACE. It is way too small by default
for things like execve.

Use __CONCAT and __XSTRING when concatenating or stringifying arguments to
the EXEC_SET macro, so that the arguments themselves can be macros.
(Actually __STRING would suffice, instead of __XSTRING, but oh well).

Remove __P

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

$Id$ -> $FreeBSD$

Well folks, this is it - The second stage of the removal for build support
for LKM's..

More -Wall / -Wcast-qual cleanup. Also, EXEC_SET can't use
C_DECLARE_MODULE due to the linker_file_sysinit() function
making modifications to the data.

Have EXEC_SET use C_DECLARE_MODULE instead of DECLARE_MODULE.

Add C_DECLARE_MODULE - same as DECLARE_MODULE but uses C_SYSINIT
instead of SYSINIT.

The C_ items are going to be used for items passing const data to
sysinit.

Removed the cast to a pointer in the definition of PS_STRINGS and
adjusted related casts to match (only in the kernel in this commit).
The pointer was only wanted in one place in kern_exec.c. Applications
should use the kern.ps_strings sysctl instead of PS_STRINGS, so they
shouldn't notice this change.

Finished updating module event handlers to be compatible with
modeventhand_t.

*gulp*. Jordan specifically OK'ed this..

This is the bulk of the support for doing kld modules. Two linker_sets
were replaced by SYSINIT()'s. VFS's and exec handlers are self registered.
kld is now a superset of lkm. I have converted most of them, they will
follow as a seperate commit as samples.
This all still works as a static a.out kernel using LKM's.

Update the ELF image activator to use some of the exec resources rather
than rolling it's own. This means that it now uses the "safe"
exec_map_first_page() to get the ld.so headers rather than risking a panic
on a page fault failure (eg: NFS server goes down).
Since all the ELF tools go to a lot of trouble to make sure everything
lives in the first page for executables, this is a win. I have not seen
any ELF executable on any system where all the headers didn't fit in the
first page with lots of room to spare.
I have been running variations of this code for some time on my pure ELF
systems.

Fixed gratuitous ANSIisms.

Some staticized variables were still declared to be extern.

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Import 4.4BSD-Lite2 onto the vendor branch, note that in the kernel, all
files are off the vendor branch, so this should not change anything.

A "U" marker generally means that the file was not changed in between
the 4.4Lite and Lite-2 releases, and does not need a merge. "C" generally
means that there was a change.
[new sys/syscallargs.h file, to be "cvs rm"ed]

Mega-commit for Linux emulator update.. This has been stress tested under
netscape-2.0 for Linux running all the Java stuff. The scrollbars are now
working, at least on my machine. (whew! :-)

I'm uncomfortable with the size of this commit, but it's too
inter-dependant to easily seperate out.

The main changes:

COMPAT_LINUX is *GONE*. Most of the code has been moved out of the i386
machine dependent section into the linux emulator itself. The int 0x80
syscall code was almost identical to the lcall 7,0 code and a minor tweak
allows them to both be used with the same C code. All kernels can now
just modload the lkm and it'll DTRT without having to rebuild the kernel
first. Like IBCS2, you can statically compile it in with "options LINUX".

A pile of new syscalls implemented, including getdents(), llseek(),
readv(), writev(), msync(), personality(). The Linux-ELF libraries want
to use some of these.

linux_select() now obeys Linux semantics, ie: returns the time remaining
of the timeout value rather than leaving it the original value.

Quite a few bugs removed, including incorrect arguments being used in
syscalls.. eg: mixups between passing the sigset as an int, vs passing
it as a pointer and doing a copyin(), missing return values, unhandled
cases, SIOC* ioctls, etc.

The build for the code has changed. i386/conf/files now knows how
to build linux_genassym and generate linux_assym.h on the fly.

Supporting changes elsewhere in the kernel:

The user-mode signal trampoline has moved from the U area to immediately
below the top of the stack (below PS_STRINGS). This allows the different
binary emulations to have their own signal trampoline code (which gets rid
of the hardwired syscall 103 (sigreturn on BSD, syslog on Linux)) and so
that the emulator can provide the exact "struct sigcontext *" argument to
the program's signal handlers.

The sigstack's "ss_flags" now uses SS_DISABLE and SS_ONSTACK flags, which
have the same values as the re-used SA_DISABLE and SA_ONSTACK which are
intended for sigaction only. This enables the support of a SA_RESETHAND
flag to sigaction to implement the gross SYSV and Linux SA_ONESHOT signal
semantics where the signal handler is reset when it's triggered.

makesyscalls.sh no longer appends the struct sysentvec on the end of the
generated init_sysent.c code. It's a lot saner to have it in a seperate
file rather than trying to update the structure inside the awk script. :-)

At exec time, the dozen bytes or so of signal trampoline code are copied
to the top of the user's stack, rather than obtaining the trampoline code
the old way by getting a clone of the parent's user area. This allows
Linux and native binaries to freely exec each other without getting
trampolines mixed up.

Reorganise ps_strings in order to gain BSD/OS 2.0 binary compatability.
This is now in line with NetBSD as well..

Note that once this series of commits is finished, you must recompile
libkvm, then ps and maybe 'w'. If you are running the recently imported
sendmail-8.7, you should recompile that too (src/conf.c at least).

Fixed the type of a function pointer in struct execsw.

Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'. Fix all the bugs found. There were no serious
ones.

Latest ibcs2 changes, add errno conversion table.
Also add 256 byte spare space on the usr stack.

Prototypes, prototypes and even more prototypes. Not quite done yet, but
getting closer all the time.

Shuffled macros and definitions around to facilitate architecture
independance.

Made them all idempotent.
Reviewed by:
Submitted by:

Hmmm...my workaround for Garrett's new exec prototypes wasn't sufficient.
I guess we'll have to not specify what the args to the exec functions
are.

Terry Lambert's loadable kernel module support w/improvements from the
NetBSD group.

Added $Id$

The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.

Reviewed by: Rodney W. Grimes
Submitted by: John Dyson and David Greenman

BSD 4.4 Lite Kernel Sources