MFC r326276:

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

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.

No functional change intended.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Use prototype.

Fix build:

- Use %ll instead of %q for explicit long long casts;
- Use %j instead of %q in XFS and cast to intmax_t.

Tested with: make universe

Spelling fixes for usr.sbin/

Fix the include path for nfs_lock.h.

MFC after: 2 weeks

Don't use sys/nfs/rpcv2.h - it is part of the old kernel RPC implementation
and will be removed.

o Style previous.

Use setproctitle(3) to provide identification of the client and server
processes created by rpc.lockd.

MFC after: 1 week

Move call to ignore SIGPIPE signals before calling fork(),
so that both parent and child processes ignore this signal.

PR: bin/97768
Submitted by: Gea-Suan Lin <gslin at csie dot nctu dot edu dot tw>
MFC after: 3 days

Ignore SIGPIPE signals on write() failures.
We already check for write() failures and handle EPIPE.
Failure to handle SIGPIPE was resulting in rpc.lockd terminating.

PR: bin/97768
Reported by: Gea-Suan Lin <gslin at csie dot nctu dot edu dot tw>
MFC after: 1 day

When a user is in more than 16 groups the call to authunix_create() will
result in abort() beeing called. This is because there is a limit of
the number of groups in the RPC which is 16. When the actual number of
groups is too large it results in xdr_array() returning an error which,
in turn, authunix_create() handles by just calling abort().

Fix this by passing only the first 16 groups to authunix_create().

Add FBSDID. Add missing prototypes. Remove unused variables. Give variable
an initial value to silent compiler.

Consumers of nfslockdans() seems to think it should return 0 on success, so
make it so.

Userland change corresponding to the change in kernel/userland communication
for NFS locking.

Make this compile cleanly. It passes WARNS=2, but I haven't checked
it is so on more platforms.

When getting back an NLM DENIED response for a requested lock from the
server, map it to EAGAIN locally rather than EACCES. The NLM spec
indicates the DENIED corresponds to lock contention, not a permission
failure. This fixes O_EXLOCK/O_SHLOCK with O_NONBLOCK, which would
previously give a permission error, which in turn fixes things
like mailq(8) and lockf(1) over NFS.

Approved by: scottl (re)
Reviewed by: truckman, Andrew P Lentvorski, Jr. <bsder@allcaps.org>
Idea from: truckman

Remove a case of exposing 'struct ucred' to userspace. Use a struct xucred
for LOCKD_MSG instead.

Requested by: rwatson

Add IPv6 support.

Submitted by: Jean-Luc Richier <Jean-Luc.Richier@imag.fr>

Fixup for WARNS.

Drop privs while servicing kernel lock requests.
Restore umask used before FIFO creation.
If opening the FIFO fails, exit.
Properly check the return value of open (use == -1 instead of < 0).

leverage fixed fifo implementation (rev 1.56 of
src/sys/fs/fifofs/fifo_vnops.c) to serve locks better, my previous
workaround for lack of decent fifo system wasn't cutting it,
particularly the kernel would send a message down the fifo and
immediately close it, this would lead to delayed unlock requests
being seen by the lockd causing all sorts of badness.

Basically, don't reopen the fifo, just select(2) on it.

use syslog rather than printf so we can see what's going on in debug mode

style fixes, fix line wrap and function declaration

Userland part of nfs client/server split and cleanup.

Fix compiling without -O, some dead code was using non-existant functions,
make the code not automatically dead but actually use the debug level
in order to determine if output is needed. Fix non-existant from_addr()
by #define'ing it to inet_ntoa().

Remove hardcoded -g from Makefile.

Reported by: "John W. De Boskey" <jwd@bsdwins.com>
Tested by: "John W. De Boskey" <jwd@bsdwins.com>

remove debug code left in by accident

Implement client side NFS locks.

Obtained from: BSD/os
Import Ok'd by: mckusick, jkh, motd on builder.freebsd.org