usr.sbin: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

autofs: best effort to maintain mounttab and mountdtab

When an automounted filesystem is successfully unmounted, call
rpc.umntall(8) with the -k flag.

rpc.umntall(8) is used to clean up /var/db/mounttab on the client and
/var/db/mountdtab on the server. This is only useful for NFSv3.

PR: 251906
Reviewed by: trasz
Differential Revision: https://reviews.freebsd.org/D27801

autounmountd: set filter-specific flags for the EVFILT_FS filter

Set the filter-specific flags VQ_MOUNT and VQ_UNMOUNT for the
EVFILT_FS filter.

The filter-specific flags for the EVFILT_FS filter are undocumented, but
their usage can be found by looking up vfs_event_signal().

Reviewed by: trasz
Differential Revision: https://reviews.freebsd.org/D28975

Drop "All rights reserved" from all my stuff. This includes
Foundation copyrights, approved by emaste@. It does not include
files which carry other people's copyrights; if you're one
of those people, feel free to make similar change.

Reviewed by: emaste, imp, gbe (manpages)
Differential Revision: https://reviews.freebsd.org/D26980

Deduplicate fsid comparisons

Comparing fsid_t objects requires internal knowledge of the fsid structure
and yet this is duplicated across a number of places in the code.

Simplify by creating a fsidcmp function (macro).

Reviewed by: mjg, rmacklem
Approved by: mav (mentor)
MFC after: 1 week
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D24749

autofs: Fix autounmountd's printing of mount time.

time_t should be printed as intmax_t. Even though duration should be short, the
correct way to print is intmax_t, not long.

Reported by: ian,imp

Change autounmountd(8) to use time_t for duration instead of double

Summary:
autounmountd(8) uses doubles to handle mount time durations. However,
it must convert to integer types, time_t in particular, to do anything
meaningful. Additionally, even though it's a floating-point value in
seconds, the sub-seconds component is never used, so it's unnecessary.

Switching type to time_t fixes an assertion on powerpc64, which checks
that a sleep value that's not -1.0 is greater than 0. On powerpc64, it
happens that the value of -1.0 gets loaded as a float (perhaps a bug in
gcc), but gets compared to a double. This compares as false, so follows
through the 'sleep != -1.0' path, and fails the assert. Since the
sub-second component isn't used in the double, just drop it and deal
with whole-integer seconds.

Reviewed by: trasz
Differential Revision: https://reviews.freebsd.org/D21109

Add SPDX tags for automount(8) et al.

MFC after: 2 weeks

Make autounmountd(8) not die when traced with "truss -p".

MFC after: 1 month

Use proper argument order for calloc(3).

MFC after: 1 month

Add new unmount(2) flag, MNT_NONBUSY, to check whether there are
any open vnodes before proceeding. Make autounmound(8) use this flag.
Without it, even an unsuccessfull unmount causes filesystem flush,
which interferes with normal operation.

Reviewed by: kib@
Approved by: re (gjb@)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D7047

The <libutil.h> is an ordinary header file; should sort just like any other.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

When there are no automounted filesystems, autounmountd(8) should wait
for filesystem event, instead of looping on a timeout.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Use __FBSDID() properly.

Suggested by: pluknet@
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

Remove useless - and buggy, it resulted in spurious warnings in logs - code.

MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

Bring in the new automounter, similar to what's provided in most other
UNIX systems, eg. MacOS X and Solaris. It uses Sun-compatible map format,
has proper kernel support, and LDAP integration.

There are still a few outstanding problems; they will be fixed shortly.

Reviewed by: allanjude@, emaste@, kib@, wblock@ (earlier versions)
Phabric: D523
MFC after: 2 weeks
Relnotes: yes
Sponsored by: The FreeBSD Foundation