- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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

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

Add option to lockf to avoid creating a file if it does not exist.

PR: bin/170775
Submitted by: Matthew Story <matthewstory@gmail.com>
Reviewed by: scottl
MFC after: 1 week

Remove trailing whitespace per mdoc lint warning

Disussed with: gavin
No objection from: doc
Approved by: joel
MFC after: 3 days

mdoc: order prologue macros consistently by Dd/Dt/Os

Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.

Reviewed by: ru
Approved by: philip, ed (mentors)

Lockf was exiting with status 1 if the command did not exit normally.
This is easy to confuse with the actual exit status of the program.
Instead exit with EX_SOFTWARE if the command doesn't exit normally.

MFC after: 1 month

Also fix a "blank line" issue that sneaked in from rev. 1.19.

Submitted by: John Hein

Remove newly acquired hard sentence breaks.

Revision 1.12 of lockf.c fixed a "thundering herd" scenario when the
lock experienced contention a number of processes would race to acquire
lock when it was released. This problem resulted in a lot of CPU
load as well as locks being picked up out of order.

Unfortunately, a regression snuck in which allowed multiple threads
to pickup the same lock when -k was not used. This could occur when
multiple processes open a file descriptor to inode X (one process
will be blocked) and the file is unlinked on unlock (thereby removing
the directory entry allow another process to create a new directory
entry for the same file name and lock it).

This changes restores the old algorithm of: wait for the lock, then
acquire lock when we want to unlink the file on exit (specifically
when -k is not used) and keeps the new algorithm for when -k is used,
which yields fairness and improved performance.

Also, update the man page to inform users that if lockf(1) is being
used to facilitate concurrency between a number of processes, it
is recommended that -k be used to reduce CPU load and yeld
fairness with regard to lock ordering.

Collaborated with: jdp
PR: bin/114341
PR: bin/116543
PR: bin/111101
MFC after: 1 week

Markup cosmetics.

Finish off style(9) fixes which I started two revisions ago. This basically
changes the indentation style from 4 spaces to 8 spaces which we expect to
see in other FreeBSD source files.

Do not ignore ENOENT

Pointed out by: Amir Shalem

Un-break handling of -t 0 which was broken in my previous commit.
Add a flags argument to wait_for_lock so that O_NONBLOCK can be
passed to open if a user doesn't want the open to sleep until the
lock becomes available.

Submitted by: Amir Shalem (partially modified)

Fix long standing race condition associated with how lockf uses open(2)
for mutual exclusion:

A brief description of the problem:

1) Proc A picks up non-blocking lock on file X
2) Proc B attempts to pickup lock, fails then waits
3) Proc C attempts to pickup lock, fails then waits
4) Proc A releases lock
5) Proc B acquires lock, release it to pickup a non-blocking version
6) Proc C acquires lock, release it to pickup a non-blocking version
7) Both process B and C race each other to pickup lock again

This occurs mainly because the processes do not keep the lock after they have
been waiting on it. They drop it, attempt to re-acquire it. (They use the wait
to notify when the lock has become available then race to pick it up). This
results in additional CPU utilization during the race, and can also result
in processes picking locks up out of order.

This change attempts to correct this problem by eliminating the test/acquire
race and having the operating system handle it.

Reported by: kris
Tested by: kris
MFC after: 1 week

Fix all the spelling mistakes I could find in the man pages for words
that have at least 3 characters.

MFC after: 1 week
Thanks to: Music band ``Chingon''
for keeping me company while searching for these.

Markup and wording fixes.

Approved by: re (blanket)

Document a couple of gotchas.

Added the EXIT STATUS section where appropriate.

Use warn() instead of perror().

Mechanically kill hard sentence breaks.

Consistently use FBSDID

Use `The .Nm utility'

Remove leaf node WARNS?=2 (that mainly I added). This should
help the GCC3 transition and CURRENT in general.

Warns cleanups.

mdoc(7) police: s/BSD/.Bx/ where appropriate.

Remove whitespace at EOL.

mdoc(7) police: removed HISTORY info from the .Os call.

Add history.

$Id$ -> $FreeBSD$

Add a "-k" option, to specify that the lock file should be kept
rather than removed.

Submitted by: Nick Barnes <Nick.Barnes@pobox.com>

.Sh AUTHOR -> .Sh AUTHORS. Use .An/.Aq.

lockf: usage : lockf -> usage: lockf by using fprintf instead of errx.

compare return value from getopt against -1 rather than EOF, per the final
posix standard on the topic.

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

On failure, return various exit codes from <sysexits.h>. In particular,
return EX_TEMPFAIL if the file was already locked. This makes it easier
to distinguish between lock collisions and failures within the command
being executed.

Also, don't complain if the unlink() fails in the cleanup handler. It
doesn't matter anyway, and it obscured the exit status returned from
the command that was executed.

This commit was generated by cvs2svn to compensate for changes in r21439,
which included commits to RCS files with non-trunk default branches.