Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r230998,r233792: sh: Use vfork in a few common cases.

This uses vfork() for simple commands and command substitutions containing a
single simple command, invoking an external program under certain conditions
(no redirections or variable assignments, non-interactive shell, no job
control). These restrictions limit the amount of code executed in a vforked
child.

Various incarnations of this patch have been shown to bring performance
improvements:
http://lists.freebsd.org/pipermail/freebsd-hackers/2012-January/037581.html

The use of vfork() can be disabled by setting a variable named
SH_DISABLE_VFORK.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

sh: Fix duplicate prototypes for builtins.

Have mkbuiltins write the prototypes for the *cmd functions to builtins.h
instead of builtins.c and include builtins.h in more .c files instead of
duplicating prototypes for *cmd functions in other headers.

sh: Forget about terminated background processes sooner.

Unless $! has been referenced for a particular job or $! still contains that
job's pid, forget about it after it has terminated. If $! has been
referenced, remember the job until the wait builtin has reported its
completion (either with the pid as parameter or without parameters).

In interactive mode, jobs are forgotten after termination has been reported,
which happens before primary prompts and through the jobs builtin. Even
then, though, remember a job if $! has been referenced.

This is similar to what is suggested by POSIX and should fix most memory
leaks (which also tend to cause sh to use more CPU time) with long running
scripts that start background jobs.

Caveats:
* Repeatedly referencing $! without ever doing 'wait', like
while :; do foo & echo started foo: $!; sleep 60; done
will still use a lot of memory and CPU time in the long run.
* The jobs and jobid builtins do not cause a job to be remembered for longer
like expanding $! does.

PR: bin/55346

Add the POSIX option -p to the jobs builtin command. It prints the PID of the
process leader for each job. Now the last specified option for the output
format (-l, -p or -s) wins, previously -s trumped -l.

PR: 99926
Submitted by: Ed Schouten and novel (patches modified by me)

Remove clause 3 from the UCB licenses.

OK'ed by: imp, core

Avoid using ints or shorts to store process id's, use pid_t instead.
The pgrp member of struct job was declared as a short and could not store
every possible process group ID value, the rest of them were benign because
pid_t happens to be an int.

Make the message that is printed when the foreground process is terminated
by a signal the same as pdksh/bash/sh before rev. 1.34.

Add -s (output PID's only) and -l (show PID's) options to the jobs(1)
builtin. Modify the output format to match what SUSv3 requires.

Instead of keeping just the jobid of the most recently bg'd or fg'd job,
keep a linked list of the jobs, most recently used first. This is required
to support the idea of `previous job', and to allow the jobs fg and bg
default to be correct according to POSIX.

o __P has been reoved
o Old-style K&R declarations have been converted to new C89 style
o register has been removed
o prototype for main() has been removed (gcc3 makes it an error)
o int main(int argc, char *argv[]) is the preferred main definition.
o Attempt to not break style(9) conformance for declarations more than
they already are.
o Change
int
foo() {
...
to
int
foo(void)
{
...

$Id$ -> $FreeBSD$

Next approach to make loops in interactive interruptable.

PR: bin/9173

Narrow down conditions to break wait() to process traps.
Improve comments.

If traps are set, they are now executed even when a signal-blocking
foreground child is running. Formerly, traps were exceuted after the
next child exit.

The enables the user to put a breaking wrapper around a blocking
application:
(trap 'echo trap ; exit 1' 2; ./pestyblocker; echo -n)

The "echo -n" after the child call is needed to prevent sh from
optimizing the trap-executing shell away. I'm working on this.

Improve bookkeeping of in_waitcmd and style fixes.
Submitted by: Bruce Evans

Do not exit on SIGINT in non-interactive shells, fixes PR 1206,
i.e. this makes emacs usable from system(3). Programs called from
shellscripts are now required to exit with proper signal status. That
means, they have to kill themself. Exiting with faked numerical exit
code is not sufficient.

Exit with proper signal status if script exits on signal.

Make the wait builtin interruptable, both with and without traps set.

Use volatile sig_atomic_t where (and only where) appropriate.

(Almost) fix printing of newlines on SIGINT.

Make traps setable from trap handlers. This is needed for shellscripts
that catch SIGINT for cleanup work but intend to exit on it, hance
have to kill themself from a trap handler. I.e. mkdep.

While I'm at it, make it -Wall clean. -Wall is not enabled in
Makefile, since vararg warnx() macro calls in usr.bin/printf/printf.c
are not -Wall-able.
PR: 1206
Obtained from: Basic SIGINT fix from Bruce Evans

Make all status values an integral type and use
pid_t when referring to process IDs.

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.

Merge of 4.4-Lite2 sh source, plus some gcc -Wall cleaning. This is a
merge of parallel duplicate work by Steve Price and myself. :-]

There are some changes to the build that are my fault... mkinit.c was
trying (poorly) to duplicate some of the work that make(1) is designed to
do. The Makefile hackery is my fault too, the depend list was incomplete
because of some explicit OBJS+= entries, so mkdep wasn't picking up their
source file #includes.

This closes a pile of /bin/sh PR's, but not all of them..

Submitted by: Steve Price <steve@bonsai.hiwaay.net>, peter

Added $Id$

This commit was generated by cvs2svn to compensate for changes in r1556,
which included commits to RCS files with non-trunk default branches.

BSD 4.4 Lite bin Sources