MFC r315733, r315737, r315740, r330054:

r315733 (imp):
Impelemnt ttys onifexists in init.

Implement a new init(8) option in /etc/ttys. If this option is present
on the entry in /etc/ttys, the entry will be active if and only if it
exists. If the name starts with a '/', it will be considered an
absolute path. If not, it will be a path relative to /dev.

This allows one to turn off video console getty that aren't present
(while running a getty on them even when they aren't the system
console). Likewise with serial ports.

It differs from onifconsole in only requiring the device exist rather
than it be listed as one of the system consoles.

r315737 (ngie):
Unbreak world by adding sys/stat.h for stat(2)

r315740 (imp):
Simplify the code a little.

r330054 (trasz):
Improve missing tty handling in init(8). This removes a check that did
nothing - it was checking for ENXIO, which, with devfs, is no longer
returned - and was badly placed anyway, and replaces it with similar
one that works, and is done just before starting getty, instead of being
done when rereading ttys(5).

From the practical point of view, this makes init(8) handle disappearing
terminals (eg /dev/ttyU*) gracefully, without unneccessary getty restarts
and resulting error messages.

Reported by: Bart Ender, Andre Albsmeier
PR: 228315
Blocks: 11.2-BETA2
Approved by: re (marius)
Sponsored by: The FreeBSD Foundation

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

MFC r315734:

style(9): sort #includes

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

Add a new flag to /etc/ttys: onifconsole. This is equivalent to "on" if the
device is an active kernel console and "off" otherwise. This is designed to
allow serial-booting x86 systems to provide a login prompt on the serial line
by default without providing one on all systems by default.

Comments and suggestions by: grehan, dteske, jilles
MFC after: 1 month

libc: Make various internal file descriptors close-on-exec.

These are obtained via fopen().

Replace index() and rindex() calls with strchr() and strrchr().

The index() and rindex() functions were marked LEGACY in the 2001
revision of POSIX and were subsequently removed from the 2008 revision.
The strchr() and strrchr() functions are part of the C standard.

This makes the source code a lot more consistent, as most of these C
files also call into other str*() routines. In fact, about a dozen
already perform strchr() calls.

Remove pseudo-terminals from ttys(5).

When we had utmp(5), we had to list all the psuedo-terminals in ttys(5)
to make ttyslot(3) function properly. Now that pututxline(3) deals with
slot allocation internally (not based on TTY names), we don't need to
list all the TTYs on the system in ttys(5) to make user accounting work
properly.

This patch removes all the entries from the /etc/ttys files, but also
the pts(4) entries that were appended implicitly, which was added in
r154838.

Fix many "function declaration isn't a prototype" warnings in libc.

I've only fixed code that seems to be written by `us'. There are still
many warnings like this present in resolv/, rpc/, stdtime/ and yp/.

Properly invalidate highest pts number when calling setttyent().

When calling setttyent() after calling endttyent(), pts_valid will never
be set to 1, because the readdir()-loop will likely never vind a pts
that has a higher number than before.

Simplify the code by removing pts_valid. We'll just set maxpts to -1
when we don't have a valid count yet.

In getttyent(3), if /etc/ttys doesn't end in a newline, don't
freak out and keep trying to expand the buffer until realloc()
fails.

PR: 114398

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

Remove debug printf.

Make getttyent() report what the pts ptys as well.

Move initialization above point of first possible reference to
avoid overwriting ty_status values set from the 'type' field.

Previously TTY_DIALUP and TTY_NETWORK flags did not match
specified type.

* Remove __P and convert to ANSI prototypes.
* Remove 'register'. (some functions had 7+ register functions...)
* Fix SCM ID's.

Add unsigned char cast to isspace arg

Fix typo.

Implement two new keywords and status flags for entries in /etc/ttys;
TTY_NETWORK (network), TTY_DIALUP (dialup), which determine a basic
connection type. TTY_DIALUP in particular will replace the old out of
date heuristic "tty[dD]*" in login.c (and better than the current
hard-coded method).

Allow commonly-used "insecure" as a valid keyword in /etc/ttys.
This prevents keywords after "insecure" occurs being errnoeously
parsed as comments.

Added group= facility to /etc/ttys for tty grouping for more
more manageable and convenient referencing by login.conf (login
class database) and (e.g.) login.access.

This is the first of a group of commits which implements the login
class capabilities database.

Don't free the line buffer, since getttynam(3) might still reference
it.

Closes PR # bin/2196: Bug in src/libc/gen/gettty...

Submitted by: davidn@blaze.net.au (David Nugent)

Fix a potential memory leak i've introduced with my recent patch.

Reviewed by: bde

Remove the arbitrary limit for the line length in /etc/ttys, and make
the buffer dynamic.

Closes PR # misc/1838: getttyent() arbitrary 100...

General -Wall warning cleanup, part I.
Submitted-By: Kent Vander Velden <graphix@iastate.edu>

Don't cast void functions to void.
Obtained from: NetBSD commit by jtc on June 16, 1995.

This commit was generated by cvs2svn to compensate for changes in r1573,
which included commits to RCS files with non-trunk default branches.

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