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.

MFC r308443, r308459, r308462, r308478, r308786

r308443:
Add -d flag that prints domain only.

PR: 212875
Submitted by: Ben RUBSON <ben.rubson@gmail.com>
Reviewed by: pi

r308459:
Fix missing '-' for the flags -s and -d on both manpage and usage.

Reported by: garga, bde

r308462:
Add flag -B which does the same like batch mode but without exiting after
print. Also add a new flag -s that add blocks size to statistics.

PR: 198347, 212726
Submitted by: Ben RUBSON <ben.rubson@gmail.com>
Tested by: pi
MFC After: 2 weeks.

r308478:
We can't use protect(1) inside a jail(8)!
To avoid have warning for services that are using oomprotect, oomprotect
will only be applied on services that won't run inside jails.

Reported by: allanjude
MFC after: 2 weeks.

r308786:
rc.subr: Swap checks so we only fork sysctl if *_oomprotect is set.

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

Fix gstat's interactive f and q commands

curses and libedit don't play well together. After last year's libedit
upgrade in head, they play even less well together. This change resets some
curses settings after they get screwed up by libedit calls. Without it,
gstat's interactive commands require an extra "enter", screw up the terminal
on exit, and screw up the display if the user enters an invalid filter
string.

PR: 204852
Submitted by: Keith White
Reviewed by: pfg
Approved by: re (gjb)
MFC after: 4 weeks
Sponsored by: Spectra Logic Corp
Differential Revision: https://reviews.freebsd.org/D6934

Update dependencies after r291406 added libelf to libkvm.

Unfortunately filemon/meta mode tracks all indirect dependencies here
since ld(1) is reading libelf when linking in libkvm. Churn would be
reduced if this was able to be limited to direct dependencies.

Sponsored by: EMC / Isilon Storage Division

Use strlcpy() in favor of strncpy() as it's defined to have a nul character
at the end of string buffer, and the code context do expects this to behave
correctly (e.g. strchr).

Note that we do not believe there is real-world impact for gstat(8)'s usage
because the strings are length checked, and the on-stack buffer belongs to
main() and we can expect to have zeros in them.

MFC after: 2 weeks

Add META_MODE support.

Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.

Still need to add real targets under targets/ to build packages.

Differential Revision: D2796
Reviewed by: brooks imp

Convert usr.sbin to LIBADD
Reduce overlinking

Convert LIBCURSES to LIBNCURSES to fix "make checkdpadd"

Also, add a missing LIBPANEL dependency for lldb

Approved by: rpaulo (mentor)
Suggested by: brooks
MFC after: 5 days
Phabric: D675 (as part of a larger diff)
PR: 192762

Add an option, -p, which makes gstat(8) to only display physical providers
(those with rank of 1).

MFC after: 2 weeks

Add -o option to gstat to display "other" operatins (e.g. BIO_FLUSH).

MFC after: 1 week

The last big commit: let usr.sbin/ use WARNS=6 by default.

o Turn the batch mode on if stdout is not tty.

Submitted by: vsevolod
MFC after: 1 week

o Sync synopsis with reality. Remove BUG section -- there is
a batch mode in gpart(8) now.

- Allow gstat to print values to different kind of outputs.
- Introduce batch mode, where gstat will collect the numbers, print them, and
exit.
- Document batch mode in the gstat man page.

Submitted by: anders

When the ms/req fields exceed 1 second, drop the fractions to fit more digits.

This is unfortunately necessary with some flash based devices which can
get hundreds of seconds behind with softupdates enabled.

Deterministically set the default refresh interval to one second.

Approved by: phk
MFC after: 1 week

Add missing library dependencies and sort libraries
using lorder(1) so that static linkage is possible.

Language tweak.

- Add support for filtering the the list of providers by a regular
expression, which makes it possible to only see interesting
providers. "f" is used inside gstat to set a filter, "F" is used to
remove current filter.
- Do not print some uninteresting values in the gstat title line.
- Do not print past the end of the screen.
- Read multiple keystrokes per "wait" when gstat is running.
- Remove a redundant != check, right after check of NULL against the
same variable ("gid").
- Use sysexits.h.
- Do not link against libkvm and libsbuf, they are not actually used.
- Fix a few style(9) issues where I had to touch nearby code anyway.

Approved by: cperciva (mentor)
MFC after: 2 weeks

Add cross-references to iostat, systat and vmstat.

Remove unnecessary SRCS= where could be guessed directly by our
bsd.*.mk infrasture.

Obtained from: ru

Added the EXIT STATUS section where appropriate.

Add forgotten -a to the usage() message.

Add an '-a' switch to only display providers that are at least
0.1% busy.

OK'ed by: phk

Added forgotten -d to the usage().

Markup nits.

Remove spurious semicolons. Outside of functions they are actually errors but
GCC doesn't warn about them without -pedantic.

Approved by: das (mentor)
PR: 56649
Reviewed by: md5

Correct a typo in column header.

Submitted by: phk
Obtained from: BSDCan

Make libgeom usable by C++ programs:
- Add DECL wrappers to libgeom.h.
- Rename structure members in libgeom.h to use a lg_ prefix for member
names. This is required because a few structures had members named
'class' which made g++ very unhappy.
- Catch gstat(8) and gconcat(8) up to these API changes.

Reviewed by: phk

Add -d flag to monitor BIO_DELETE operations too

Sigh, I guess this manpage used cat(1) as a template?

Otherwise, fix the manpage to not use the second person,
and add two missing punctuation bits.

Install the gstat manual page.

Make -c only set flag_c and not a toggle. With flag_c disabled by
default, this makes the behavior of gstat more predictable when -c is
specified multiple times on the command line.

Add a small manpage.

Add & use a usage() function.

Add error and range checking to strtoul() to avoid ending up with a
delay time of ULONG_MAX when -I is passed a non-numeric arg.

Why doesn't anybody ever tell me anything? When did we get a libsbuf ?

Geeze, I'll just crawl back into the kernel where I know what's going on...

Use libsbuf instead of pulling a file in from the kernel.

Taught by: jhb

Fixed a typo in ${.CURDIR} spelling, fatal on systems
without the /sys symlink pointing to the current tree.
(Revision 1.2 made it non-fatal, but anyway.)

Apply style.Makefile(5).

Fixed ``make checkdpadd''.

Duh! Use correct number ../

spotted by: imp

Call endwin() to restore terminal state just before exiting.

Approved by: phk

Add a rudimentary gstat(8) to the system.

This is a small curses based program which shows the diskactivity
inside GEOM.