Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Fix typo.

MFC after: 3 days

Fix copyright spelling

PR: 139825
Submitted by: Ruslan Mahmatkhanov

Fix our ioctl(2) implementation when the argument is "int". New
ioctls passing integer arguments should use the _IOWINT() macro.
This fixes a lot of ioctl's not working on sparc64, most notable
being keyboard/syscons ioctls.

Full ABI compatibility is provided, with the bonus of fixing the
handling of old ioctls on sparc64.

Reviewed by: bde (with contributions)
Tested by: emax, marius
MFC after: 1 week

/* -> /*- for license, minor formatting changes

#define the ioctls that take no arguments correctly.

Kernel modifications necessary to allow to follow fork()ed children.

PR: bin/25587 (in part)
MFC after: 3 weeks

Add the as-yet-unused S_ALLSTOPS which I forgot in previous commit.

Upon further reflection, back out previous commit, partly for the reasons
Bruce stated and partly because it introduces gratuitous incompatibilities
with -STABLE.

Move the stop event macros from pioctl.h to proc.h, and add an S_ALLSTOPS
macro to represent "all stop events".

$Id$ -> $FreeBSD$

Add a copyright and license notice, on Jordan's request.

Clear the p_stops field on change of user/group id, unless the correct
flag is set in the p_pfsflags field. This, essentially, prevents an SUID
proram from hanging after being traced. (E.g., "truss /usr/bin/rlogin" would
fail, but leave rlogin in a stopevent state.) Yet another case where procctl
is (hopefully ;)) no longer needed in the general case.

Reviewed by: bde (thanks bruce :))

Explicitly use the _IOC macro directly. This changes the ioctl command
numbers, so any programs using it need to be recompiled.

Change the ioctls for procfs around a bit; in particular, whever possible,
change from

ioctl(fd, PIOC<foo>, &i);

to

ioctl(fd, PIOC<foo>, i);

This is going from the _IOW to _IO ioctl macro. The kernel, procctl, and
truss must be in synch for it all to work (not doing so will get errors about
inappropriate ioctl's, fortunately). Hopefully I didn't forget anything :).

A couple of fixes from bruce: first of all, psignal is a void (stupid
me; unfortunately, also makes it hard ot check for errors); second, I had
managed to forget a change to PIOCSFL (it should be _IOW, not _IOR) I had
in my local copy, and Bruce called me on it.

Submitted by: bde

Add a procfs-related flag for procp->p_pfsflags.

Changes to allow event-based process monitoring and control.