Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

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

strchr(3) will return NULL if it cannot find the character in the
string.
getfsent(3) will return NULL on EOF or error.

MFC after: 2 weeks.

Make fsck and fsck_msdosfs WARNS=6 clean

- sprinkle const
- add volatile qualifier to avoid vfork clobbering

Inspired by: NetBSD
PR: bin/139802
Reviewed by: ed

sbin/fsck: s/perror/perr/ to avoid shadowing

- rename some other vars too
- merge NetBSD license changes

Obtained from: NetBSD
PR: bin/139802
Reviewed by: ed

Add missing static keywords for global variables to tools in sbin/.

These tools declare global variables without using the static keyword,
even though their use is limited to a single C-file, or without placing
an extern declaration of them in the proper header file.

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

Approved by: core, imp

Straighten out a compound if() to improve readability marginally.

s/filesystem/file system/g as discussed on -developers

o __P removed
o ansi function prototypes
o unifdef -D__STDC__
o __dead2 on usage prototype
o remove now-bogus main prototype

Add support for running foreground (-F) and background (-B) checks.
Traditionally, fsck is invoked before the filesystems are mounted
and all checks are done to completion at that time. If background
checking is available, fsck is invoked twice. It is first invoked
at the traditional time, before the filesystems are mounted, with
the -F flag to do checking on all the filesystems that cannot do
background checking. It is then invoked a second time, after the
system has completed going multiuser, with the -B flag to do checking
on all the filesystems that can do background checking. Unlike
the foreground checking, the background checking is started
asynchonously so that other system activity can proceed even on
the filesystems that are being checked.

At the moment, only the fast filesystem supports background checking.
To be able to do background checking, a filesystem must have been
running with soft updates, not have been marked as needing a
foreground check, and be mounted and writable when the background
check is to be done (i.e., not listed as `noauto' in /etc/fstab).

These changes are the final piece needed to support background
filesystem checking. They will not have any effect until you update
your /etc/rc to invoke fsck in its new mode of operation. I am
still playing around with exactly what those changes should be
and should be committing them later this week.

Don't make fsck go quite _that_ fast:
In Preen mode we only checked one partition per disk device.

This change sanitizes the way fsck deals with pass numbers.

Consider this /etc/fstab:

# Device Mountpoint FStype Options Dump Pass#
/dev/ad1s1b none swap sw 0 0
/dev/ad0s1b none swap sw 0 0
/dev/ad0s1a / ufs rw 1 1
/dev/ad0s1e /home ufs rw 2 2
/dev/ad1s1e /tmp ufs rw 2 2
/dev/ad1s1f /usr ufs rw 2 2
/dev/ccd0c /syv ufs rw 2 11
proc /proc procfs rw 0 0

ccd0c is striped over /dev/ad0f and /dev/ad1g

Without this pass, fsck in preen mode will check ad0s1a first,
and then issue three processes in parallel:

One process doing ad0s1e
One process doing ad1s1e and ad1s1f
One process doing ccd0c

There is no way to tell it that ccd0c overlaps ad0 and ad1.

With the patch, it will do it this way:

pass 2:
One process doing ad0s1e
One process doing ad1s1e and ad1s1f

and when they are complete:

pass 11:
One process doing ccd0c

This is much faster and more sane.

Valid pass numbers are anything from 1 to INTMAX-1.

I retired the '-l' option which tried to allow people to do
something like this, but which didn't work and which complicated
the code an awful lot.

Use macro API to <sys/queue.h>

Submitted by: "Peter Avalos" <pavalos@theshell.com>
Reviewed by: /sbin/md5

When trying to deduce the diskname from the name so we can run
parallel fsck's one per drive, use the shortest prefix ending in
a digit rather than the longest prefix ending in a digit.

This makes "/dev/ad0s1a" and "/dev/ad0s2a" appear to both reside
on the disk "/dev/ad0" and consequently they will be fsck'ed
sequentially rather than in parallel as now.

In general this heuristic is rather soft and errorprone. For
instance ccd may often reside on two or more physical disks. A
good solution would be to look for passes larger than 1 until no
disks are found in a particular pass, that way people could put
ccd stripes in pass 3... and have them fsck'ed sequentially.

Reviewed by: mjacob

Use official API to <sys/queue.h> instead of groping around inside the
data structures.

Reviewed by: imp

.. fsck wrappers aftercommit #1: I don't know how these files got lost,
but they did. Oops.