CVS log for src/bin/sh/expand.h

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PR bin/53550

Here we go again...   One more time to redo how here docs are
processed (it has been a few years since the last time!)

This is actually a relatively minor change, mostly to timimg
(to just when things happen).   Now here docs are expanded at the
same time the "filename" word in a redirect is expanded, rather than
later when the heredoc was being sent to its process.  This actually
makes things more consistent - but does break one of the ATF tests
which was testing that we were (effectively) internally inconsistent
in this area.

Not all shells agree on the context in which redirection expansions
should happen, some make any side effects visible to the parent shell
(the majority do) others do the redirection expansions in a subshell
so any side effcts are lost.   We used to have a foot in each camp,
with the majority for everything but here docs, and the minority for
here docs.   Now we're all the way with LBJ ... (or something like that).

Pull up following revision(s) (requested by kre in ticket #940):

	bin/sh/expand.h: revision 1.25
	bin/sh/expand.c: revision 1.134
	bin/sh/expand.c: revision 1.135
	bin/sh/expand.c: revision 1.136
	bin/sh/expand.c: revision 1.137

Remove a (completely harmless) duplicate assignment introduced in a
code merge from FreeBSD in 2017.   NFC.

Pointed out by Roland Illig.

prevent sign extension from making expression always false.
remove masking and cast (requested by kre@)

When expanding a here-doc (NXHERE - the type with an unquoted end delim)
the output will not be further processed (at all) so there is no need
to escape magic chars in the output, and doing so leaves stray CTLESC
chars in the here doc text.  Not good.   So don't do that...

To save a strlen() of the result, to determine the size of the here doc,
make rmescapes() return the length of the resulting string (this isn't
needed for other uses, so didn't happen previously).

Reported on current-users@ (2020-02-06) by Jun Ebihara

XXX pullup -9

Ooops, restore accidently removed files from merge mishap

Sync with HEAD

Merge changes from current as of 20200406

When expanding a here-doc (NXHERE - the type with an unquoted end delim)
the output will not be further processed (at all) so there is no need
to escape magic chars in the output, and doing so leaves stray CTLESC
chars in the here doc text.  Not good.   So don't do that...

To save a strlen() of the result, to determine the size of the here doc,
make rmescapes() return the length of the resulting string (this isn't
needed for other uses, so didn't happen previously).

Reported on current-users@ (2020-02-06) by Jun Ebihara

XXX pullup -9

Sync with HEAD

Sync with HEAD, resolve a couple of conflicts

Rationalise (slightly) the way that expansions are processed
to hide meta-characters in the result when the expansion was
in (double) quotes, and so should not be further processed.

Most of this has been OK for a long while, but \ needs hiding
as well, which complicates things, as \ cannot simply be hidden
in the syntax tables as one of the group of random special characters.

This was fixed earlier for simple variable expansions, but
every variety has its own code path ($var uses different code
than $n which is different than $(...), which is different
again from ~ expansions, and also from what $'...' produces).

This could be fixed by moving them all to a common code path,
but that's harder than it seems.  The form in which the data
is made available differs, so one common routine would need
a whole bunch of different "get the next char or indicate end"
methods - probably via passing in an accessor function.
That's all a lot of churn, and would probably slow the shell.

Instead, just make macros for doing the standard tests, and
use those instead of open coding (differently) each time.
This way some of the code paths don't end up forgetting to
handle '\' (which is different than all the others).

This removes one optimisation ... when no escaping is needed
(like just $var (unquoted) where magic chars (think '*') in
the value are intended to remain magic), the code avoided doing
two tests for each char ("do we need escapes" and "is this char
one that needs escaping") by choosing two different syntax
tables (choice made outside the loop) - one of which never
returns the magic "needs escaping" result, and the other does
when appropriate, and then just avoiding the "do we need escapes"
test for each character processed.   Then when '\' was fixed,
there needed to be another test for it, as it cannot (for other
reasons) be the same as all the others for which "this char
need escaping" is true.   So that added a 2nd test for each char...
Not all the code paths were updated.   Hence the bugs...

nb: this is all rarely seen in the wild, so it is no big
surprised that no-one ever noticed.

Now the "use two different syntax tables" is gone (the two
returned the same for '\' which is why '\' needed special
processing) - and in order to avoid two tests for each
char (plus the \ test) we duplicate the loops, one of which
tests each char to see if it needs an escape, the 2nd just
copies them.   This should be faster in the "no escapes"
code path (though that is not the point) and perhaps also
in the "escapes needed" path (no indirect reference to
the syntax table - though that would probably be in a
register) but makes the code slightly bigger.  For /bin/sh
the text segment (on amd64) has grown by 48 bytes.  But
it still uses the same number of 512 byte pages (and hence
also any bigger page size).  The resulting file size
(/bin/sh) is identical before and after.  So is /rescue/sh
(or /rescue/anything-else).

Pull up following revision(s) (requested by kre in ticket #103):
	bin/kill/kill.c: 1.28
	bin/sh/Makefile: 1.111-1.113
	bin/sh/arith_token.c: 1.5
	bin/sh/arith_tokens.h: 1.2
	bin/sh/arithmetic.c: 1.3
	bin/sh/arithmetic.h: 1.2
	bin/sh/bltin/bltin.h: 1.15
	bin/sh/cd.c: 1.49-1.50
	bin/sh/error.c: 1.40
	bin/sh/eval.c: 1.142-1.151
	bin/sh/exec.c: 1.49-1.51
	bin/sh/exec.h: 1.26
	bin/sh/expand.c: 1.113-1.119
	bin/sh/expand.h: 1.23
	bin/sh/histedit.c: 1.49-1.52
	bin/sh/input.c: 1.57-1.60
	bin/sh/input.h: 1.19-1.20
	bin/sh/jobs.c: 1.86-1.87
	bin/sh/main.c: 1.71-1.72
	bin/sh/memalloc.c: 1.30
	bin/sh/memalloc.h: 1.17
	bin/sh/mknodenames.sh: 1.4
	bin/sh/mkoptions.sh: 1.3-1.4
	bin/sh/myhistedit.h: 1.12-1.13
	bin/sh/nodetypes: 1.16-1.18
	bin/sh/option.list: 1.3-1.5
	bin/sh/parser.c: 1.133-1.141
	bin/sh/parser.h: 1.22-1.23
	bin/sh/redir.c: 1.58
	bin/sh/redir.h: 1.24
	bin/sh/sh.1: 1.149-1.159
	bin/sh/shell.h: 1.24
	bin/sh/show.c: 1.43-1.47
	bin/sh/show.h: 1.11
	bin/sh/syntax.c: 1.4
	bin/sh/syntax.h: 1.8
	bin/sh/trap.c: 1.41
	bin/sh/var.c: 1.56-1.65
	bin/sh/var.h: 1.29-1.35
An initial attempt at implementing LINENO to meet the specs.
Aside from one problem (not too hard to fix if it was ever needed) this version
does about as well as most other shell implementations when expanding
$((LINENO)) and better for ${LINENO} as it retains the "LINENO hack" for the
latter, and that is very accurate.
Unfortunately that means that ${LINENO} and $((LINENO)) do not always produce
the same value when used on the same line (a defect that other shells do not
share - aside from the FreeBSD sh as it is today, where only the LINENO hack
exists and so (like for us before this commit) $((LINENO)) is always either
0, or at least whatever value was last set, perhaps by
	LINENO=${LINENO}
which does actually work ... for that one line...)
This could be corrected by simply removing the LINENO hack (look for the string
LINENO in parser.c) in which case ${LINENO} and $((LINENO)) would give the
same (not perfectly accurate) values, as do most other shells.
POSIX requires that LINENO be set before each command, and this implementation
does that fairly literally - except that we only bother before the commands
which actually expand words (for, case and simple commands).   Unfortunately
this forgot that expansions also occur in redirects, and the other compound
commands can also have redirects, so if a redirect on one of the other compound
commands wants to use the value of $((LINENO)) as a part of a generated file
name, then it will get an incorrect value.  This is the "one problem" above.
(Because the LINENO hack is still enabled, using ${LINENO} works.)
This could be fixed, but as this version of the LINENO implementation is just
for reference purposes (it will be superseded within minutes by a better one)
I won't bother.  However should anyone else decide that this is a better choice
(it is probably a smaller implementation, in terms of code & data space then
the replacement, but also I would expect, slower, and definitely less accurate)
this defect is something to bear in mind, and fix.
This version retains the *BSD historical practice that line numbers in functions
(all functions) count from 1 from the start of the function, and elsewhere,
start from 1 from where the shell started reading the input file/stream in
question.  In an "eval" expression the line number starts at the line of the
"eval" (and then increases if the input is a multi-line string).
Note: this version is not documented (beyond as much as LINENO was before)
hence this slightly longer than usual commit message.
A better LINENO implementation.   This version deletes (well, #if 0's out)
the LINENO hack, and uses the LINENO var for both ${LINENO} and $((LINENO)).
(Code to invert the LINENO hack when required, like when de-compiling the
execution tree to provide the "jobs" command strings, is still included,
that can be deleted when the LINENO hack is completely removed - look for
refs to VSLINENO throughout the code.  The var funclinno in parser.c can
also be removed, it is used only for the LINENO hack.)
This version produces accurate results: $((LINENO)) was made as accurate
as the LINENO hack made ${LINENO} which is very good.  That's why the
LINENO hack is not yet completely removed, so it can be easily re-enabled.
If you can tell the difference when it is in use, or not in use, then
something has broken (or I managed to miss a case somewhere.)
The way that LINENO works is documented in its own (new) section in the
man page, so nothing more about that, or the new options, etc, here.
This version introduces the possibility of having a "reference" function
associated with a variable, which gets called whenever the value of the
variable is required (that's what implements LINENO).  There is just
one function pointer however, so any particular variable gets at most
one of the set function (as used for PATH, etc) or the reference function.
The VFUNCREF bit in the var flags indicates which func the variable in
question uses (if any - the func ptr, as before, can be NULL).
I would not call the results of this perfect yet, but it is close.
Unbreak (at least) i386 build .... I have no idea why this built for me on
amd64 (problem was missing prototype for snprintf witout <stdio.h>)
While here, add some (DEBUG mode only) tracing that proved useful in
solving another problem.
Set the line number before expanding args, not after.   As the line_number
would have usually been set earlier, this change is mostly an effective
no-op, but it is better this way (just in case) - not observed to have
caused any problems.
Undo some over agressive fixes for a (pre-commit) bug that did not
need these changes to be fixed - and these cause problems in another
absurd use case.   Either of these issues is unlikely to be seen by
anyone who isn't an idiot masochist...
PR bin/52280
removescapes_nl in expari() even when not quoted,
CRTNONL's appear regardless of quoting (unlike CTLESC).
New sentence, new line. Whitespace.
Improve the (new) LINENO section, markup changes (with thanks to wiz@ for
assistace) and some better wording in a few placed.
I am an idiot...  revert the previous unintended commit.
Remove some left over baggage from the LINENO v1 implementation that
didn't get removed with v2, and should have.   This would have had
(I think, without having tested it) one very minor effect on the way
LINENO worked in the v2 implementation, but my guess is it would have
taken a long time before anyone noticed...
Correct spelling in comments of DEBUG only code...
(Perhaps) temporary fix to pkgtools (cwrappers) build (configure).
Expanding  `` containing \ \n sequences looks to have been giving
problems.   I don't think this is the correct fix, but it will do
no worse harm than (perhaps) incorrectly calculating LINENO in this
kind of (rare) circumstance.   I'll look and see if there should be
a better fix later.
s/volatile/const/ -- wonderful how opposites attract like this.
NFC (normal use) - DEBUG only change, when showing empty arg list don't
omit terminating \n.
Free stack memory in a couple of obscure cases where it wasn't
being done (one in probably dead code that is never compiled, the other
in a very rare error case.)   Since it is stack memory it wasn't lost
in any case, just held longer than needed.
Many internal memory management type fixes.
PR bin/52302   (core dump with interactive shell, here doc and error
on same line) is fixed.   (An old bug.)
echo "$( echo x; for a in $( seq 1000 ); do printf '%s\n'; done; echo y )"
consistently prints 1002 lines (x, 1000 empty ones, then y) as it should
(And you don't want to know what it did before, or why.) (Another old one.)
(Recently added) Problems with ~ expansion fixed (mem management related).
Proper fix for the cwrappers configure problem (which includes the quick
fix that was done earlier, but extends upon that to be correct). (This was
another newly added problem.)
And the really devious (and rare) old bug - if STACKSTRNUL() needs to
allocate a new buffer in which to store the \0, calculate the size of
the string space remaining correctly, unlike when SPUTC() grows the
buffer, there is no actual data being stored in the STACKSTRNUL()
case - the string space remaining was calculated as one byte too few.
That would be harmless, unless the next buffer also filled, in which
case it was assumed that it was really full, not one byte less, meaning
one junk char (a nul, or anything) was being copied into the next (even
bigger buffer) corrupting the data.
Consistent use of stalloc() to allocate a new block of (stack) memory,
and grabstackstr() to claim a block of (stack) memory that had already
been occupied but not claimed as in use.  Since grabstackstr is implemented
as just a call to stalloc() this is a no-op change in practice, but makes
it much easier to comprehend what is really happening.  Previous code
sometimes used stalloc() when the use case was really for grabstackstr().
Change grabstackstr() to actually use the arg passed to it, instead of
(not much better than) guessing how much space to claim,
More care when using unstalloc()/ungrabstackstr() to return space, and in
particular when the stack must be returned to its previous state, rather than
just returning no-longer needed space, neither of those work.  They also don't
work properly if there have been (really, even might have been) any stack mem
allocations since the last stalloc()/grabstackstr().   (If we know there
cannot have been then the alloc/release sequence is kind of pointless.)
To work correctly in general we must use setstackmark()/popstackmark() so
do that when needed.  Have those also save/restore the top of stack string
space remaining.
	[Aside: for those reading this, the "stack" mentioned is not
	in any way related to the thing used for maintaining the C
	function call state, ie: the "stack segment" of the program,
	but the shell's internal memory management strategy.]
More comments to better explain what is happening in some cases.
Also cleaned up some hopelessly broken DEBUG mode data that were
recently added (no effect on anyone but the poor semi-human attempting
to make sense of it...).
User visible changes:
Proper counting of line numbers when a here document is delimited
by a multi-line end-delimiter, as in
	cat << 'REALLY
	END'
	here doc line 1
	here doc line 2
	REALLY
	END
(which is an obscure case, but nothing says should not work.)  The \n
in the end-delimiter of the here doc (the last one) was not incrementing
the line number, which from that point on in the script would be 1 too
low (or more, for end-delimiters with more than one \n in them.)
With tilde expansion:
	unset HOME; echo ~
changed to return getpwuid(getuid())->pw_home instead of failing (returning ~)
POSIX says this is unspecified, which makes it difficult for a script to
compensate for being run without HOME set (as in env -i sh script), so
while not able to be used portably, this seems like a useful extension
(and is implemented the same way by some other shells).
Further, with
	HOME=; printf %s ~
we now write nothing (which is required by POSIX - which requires ~ to
expand to the value of $HOME if it is set) previously if $HOME (in this
case) or a user's directory in the passwd file (for ~user) were a null
STRING, We failed the ~ expansion and left behind '~' or '~user'.
Changed the long name for the -L option from lineno_fn_relative
to local_lineno as the latter seemed to be marginally more popular,
and perhaps more importantly, is the same length as the peviously
existing quietprofile option, which means the man page indentation
for the list of options can return to (about) what it was before...
(That is, less indented, which means more data/line, which means less
lines of man page - a good thing!)
Cosmetic changes to variable flags - make their values more suited
to my delicate sensibilities...  (NFC).
Arrange not to barf (ever) if some turkey makes _ readonly.  Do this
by adding a VNOERROR flag that causes errors in var setting to be
ignored (intended use is only for internal shell var setting, like of "_").
(nb: invalid var name errors ignore this flag, but those should never
occur on a var set by the shell itself.)
From FreeBSD: don't simply discard memory if a variable is not set for
any reason (including because it is readonly) if the var's value had
been malloc'd.  Free it instead...
NFC - DEBUG changes, update this to new TRACE method.
KNF - white space and comment formatting.
NFC - DEBUG mode only change - convert this to the new TRACE() format.
NFC - DEBUG mode only change - complete a change made earlier (marking
the line number when included in the trace line tag to show whether it
comes from the parser, or the elsewhere as they tend to be quite different).
Initially only one case was changed, while I pondered whether I liked it
or not.  Now it is all done...   Also when there is a line tag at all,
always include the root/sub-shell indicator character, not only when the
pid is included.
NFC: DEBUG related comment change - catch up with reality.
NFC: DEBUG mode only change.  Fix botched cleanup of one TRACE().
"b" more forgiving when sorting options to allow reasonable (and intended)
flexibility in option.list format.   Changes nothing for current option.list.
Now that excessive use of STACKSTRNUL has served its purpose (well, accidental
purpose) in exposing the bug in its implementation, go back to not using
it when not needed for DEBUG TRACE purposes.   This change should have no
practical effect on either a DEBUG shell (where the STACKSTRNUL() calls
remain) or a non DEBUG shell where they are not needed.
Correct the initial line number used for processing -c arg strings.
(It was inheriting the value from end of profile file processing) - I didn't
notice before as I usually test with empty or no profile files to avoid
complications.   Trivial change which should have very limited impact.
Fix from FreeBSD (applied there in July 2008...)
Don't dump core with input like sh -c 'x=; echo >&$x' - that is where
the word after a >& or <& redirect expands to nothing at all.
Another fix from FreeBSD (this one from April 2009).
When processing a string (as in eval, trap, or sh -c) don't allow
trailing \n's to destroy the exit status of the last command executed.
That is:
	sh -c 'false
	'
	echo $?
should produce 1, not 0.
It is amazing what nonsense appears to work sometimes... (all my nonsense too!)
Two bugs here, one benign because of the way the script is used.
The other hidden by NetBSD's sort being stable, and the data not really
requiring sorting at all...
So as it happens these fixes change nothing, but they are needed anyway.
(The contents of the generated file are only used in DEBUG shells, so
this is really even less important than it seems.)
Another ancient (highly improbable) bug bites the dust.   This one
caused by incorrect macro usage (ie: using the wrong one) which has
been in the sources since version 1.1 (ie: forever).
Like the previous (STACKSTRNUL) bug, the probability of this one
actually occurring has been infinitesimal but the LINENO code increases
that to infinitesimal and a smidgen... (or a few, depending upon usage).
Still, apparently that was enough, Kamil Rytarowski discovered that the
zsh configure script (damn competition!) managed to trigger this problem.
source .editrc after we initialize so that commands persist!
Make arg parsing in kill POSIX compatible with POSIX (XBD 2.12) by
parsing the way getopt(3) would, if only it could handle the (required)
-signumber and -signame options.  This adds two "features" to kill,
-ssigname and -lstatus now work (ie: one word with all of the '-', the
option letter, and its value) and "--" also now works (kill -- -pid1 pid2
will not attempt to send the pid1 signal to pid2, but rather SIGTERM
to the pid1 process group and pid2).  It is still the case that (apart
from --) at most 1 option is permitted (-l, -s, -signame, or -signumber.)
Note that we now have an ambiguity, -sname might mean "-s name" or
send the signal "sname" - if one of those turns out to be valid, that
will be accepted, otherwise the error message will indicate that "sname"
is not a valid signal name, not that "name" is not.   Keeping the "-s"
and signal name as separate words avoids this issue.
Also caution: should someone be weird enough to define a new signal
name (as in the part after SIG) which is almost the same name as an
existing name that starts with 'S' by adding an extra 'S' prepended
(eg: adding a SIGSSYS) then the ambiguity problem becomes much worse.
In that case "kill -ssys" will be resolved in favour of the "-s"
flag being used (the more modern syntax) and would send a SIGSYS, rather
that a SIGSSYS.    So don't do that.
While here, switch to using signalname(3) (bye bye NSIG, et. al.), add
some constipation, and show a little pride in formatting the signal names
for "kill -l" (and in the usage when appropriate -- same routine.)   Respect
COLUMNS (POSIX XBD 8.3) as primary specification of the width (terminal width,
not number of columns to print) for kill -l, a very small value for COLUMNS
will cause kill -l output to list signals one per line, a very large
value will cause them all to be listed on one line.) (eg: "COLUMNS=1 kill -l")
TODO: the signal printing for "trap -l" and that for "kill -l"
should be switched to use a common routine (for the sh builtin versions.)
All changes of relevance here are to bin/kill - the (minor) changes to bin/sh
are only to properly expose the builtin version of getenv(3) so the builtin
version of kill can use it (ie: make its prototype available.)
Properly support EDITRC - use it as (naming) the file when setting
up libedit, and re-do the config whenever EDITRC is set.
Get rid of workarounds for ancient groff html backend.
Simplify macro usage.
Make one example more like a real world possibility (it still isn't, but
is closer) - though the actual content is irrelevant to the point being made.
Add literal prompt support this allows one to do:
CA="$(printf '\1')"
PS1="${CA}$(tput bold)${CA}\$${CA}$(tput sgr0)${CA} "
Now libedit supports embedded mode switch sequence, improve sh
support for them (adds PSlit variable to set the magic character).
NFC: DEBUG only change - provide an externally visible (to the DEBUG sh
internals) interface to one of the internal (private to trace code) functions
Include redirections in trace output from "set -x"
Implement PS1, PS2 and PS4 expansions (variable expansions, arithmetic
expansions, and if enabled by the promptcmds option, command substitutions.)
Implement a bunch of new shell environment variables. many mostly useful
in prompts when expanded at prompt time, but all available for general use.
Many of the new ones are not available in SMALL shells (they work as normal
if assigned, but the shell does not set or use them - and there is no magic
in a SMALL shell (usually for install media.))
Omnibus manual update for prompt expansions and new variables.  Throw in
some random cleanups as a bonus.
Correct a markup typo (why did I not see this before the prev commit??)
Sort options (our default is 0..9AaBbZz).
Fix markup problems and a typo.
Make $- list flags in the same order they appear in sh(1)
Do a better job of detecting the error in pkgsrc/devel/libbson-1.6.3's
configure script, ie: $(( which is intended to be a sub-shell in a
command substitution, but is an arith subst instead, it needs to be
written $( ( to do as intended.   Instead of just blindly carrying on to
find the missing )) somewhere, anywhere, give up as soon as we have seen
an unbalanced ')' that isn't immediately followed by another ')' which
in a valid arith subst it always would be.
While here, there has been a comment in the code for quite a while noting a
difference in the standard between the text descr & grammar when it comes to
the syntax of case statements.   Add more comments to explain why parsing it
as we do is in fact definitely the correct way (ie: the grammar wins arguments
like this...).
DEBUG and white space changes only.   Convert TRACE() calls for DEBUg mode
to the new style.   NFC (when not debugging sh).
Mostly DEBUG and white space changes.   Convert DEEBUG TRACE() calls to
the new format.   Also #if 0 a function definition that is used nowhere.
While here, change the function of pushfile() slightly - it now sets
the buf pointer in the top (new) input descriptor to NULL, instead of
simply leaving it - code that needs a buffer always (before and after)
must malloc() one and assign it after the call.  But code which does not
(which will be reading from a string or similar) now does not have to
explicitly set it to NULL (cleaner interface.)   NFC intended (or observed.)
DEBUG changes: convert DEBUG TRACE() calls to new format.
ALso, cause exec failures to always cause the shell to exit with
status 126 or 127, whatever the cause.  127 is intended for lookup
failures (and is used that way), 126 is used for anything else that
goes wrong (as in several other shells.)  We no longer use 2 (more easily
confused with an exit status of the command exec'd) for shell exec failures.
DEBUG only changes.  Convert the TRACE() calls in the remaining files
that still used it to the new format.   NFC.
Fix a reference after free (and consequent nonsense diagnostic for
attempts to set readonly variables) I added in 1.60 by incompletely
copying the FreeBSD fix for the lost memory issue.

A better LINENO implementation.   This version deletes (well, #if 0's out)
the LINENO hack, and uses the LINENO var for both ${LINENO} and $((LINENO)).
(Code to invert the LINENO hack when required, like when de-compiling the
execution tree to provide the "jobs" command strings, is still included,
that can be deleted when the LINENO hack is completely removed - look for
refs to VSLINENO throughout the code.  The var funclinno in parser.c can
also be removed, it is used only for the LINENO hack.)

This version produces accurate results: $((LINENO)) was made as accurate
as the LINENO hack made ${LINENO} which is very good.  That's why the
LINENO hack is not yet completely removed, so it can be easily re-enabled.
If you can tell the difference when it is in use, or not in use, then
something has broken (or I managed to miss a case somewhere.)

The way that LINENO works is documented in its own (new) section in the
man page, so nothing more about that, or the new options, etc, here.

This version introduces the possibility of having a "reference" function
associated with a variable, which gets called whenever the value of the
variable is required (that's what implements LINENO).  There is just
one function pointer however, so any particular variable gets at most
one of the set function (as used for PATH, etc) or the reference function.
The VFUNCREF bit in the var flags indicates which func the variable in
question uses (if any - the func ptr, as before, can be NULL).

I would not call the results of this perfect yet, but it is close.

Fixes to shell expand (that is, $ stuff) from FreeBSD (implemented
differently...)

In particular	${01} is now $1 not $0  (for ${0any-digits})

		${4294967297} is most probably now ""
			(unless you have a very large number of params)
		it is no longer an alias for $1  (4294967297 & 0xFFFFFFFF) == 1

		$(( expr $(( more )) stuff )) is no longer the same as
		$(( expr (( more )) stuff )) which was sometimes OK, as in:
			$(( 3 + $(( 2 - 1 )) * 3 ))
		but not always as in:
			$(( 1$((1 + 1))1 ))
		which should be 121, but was an arith syntax error as
			1((1 + 1))1
		is meaningless.

Probably some more.   This also sprinkles a little const, splits a big
func that had 2 (kind of unrelated) purposes into two simpler ones,
and avoids some (semi-dubious) modifications (and restores) in the input
string to insert \0's when they were needed.

Sync with HEAD - tag prg-localcount2-base1

Convert the pattern matcher from recursive to backtracking (from FreeBSD).

Sync with HEAD

Sync with HEAD

Finish support for all required $(( )) (shell arithmetic) operators,
closing PR bin/50958

That meant adding the assignment operators ('=', and all of the +=, *= ...)
Currently, ++, --, and ',' are not implemented (none of those are required
by posix) but support for them (most likely ',' first) might be added later.

To do this, I removed the yacc/lex arithmetic parser completely, and
replaced it with a hand written recursive descent parser, that I obtained
from FreeBSD, who earlier had obtained it from dash (Herbert Xu).

While doing the import, I cleaned up the sources (changed some file names
to avoid requiring a clean build, or signifigant surgery to the obj
directories if "build.sh -u" was to be used - "build.sh -u" should work
fine as it is now) removed some dashisms, applied some KNF, ...

Pull up following revision(s) (requested by gdt in ticket #1851):
	bin/sh/expand.c: revision 1.88
	bin/sh/expand.h: revision 1.19
Fix the expansion of "$(foo-$bar}" so that IFS isn't applied when
expanding $bar.
Noted by Greg Troxel on tech-userlevel running some 'git' tests.
Should fix PR bin/47361

resync with head

Pull up the following revisions(s) (requested by dsl in ticket #773):
	bin/sh/expand.c:	revision 1.88
	bin/sh/expand.h:	revision 1.19

Fix the expansion of "$(foo-$bar}" so that IFS isn't applied when
expanding $bar. Should fix PR bin/47361

sync with head

Fix the expansion of "$(foo-$bar}" so that IFS isn't applied when
expanding $bar.
Noted by Greg Troxel on tech-userlevel running some 'git' tests.
Should fix PR bin/47361

Catchup with rmind-uvmplock merge.

PR/45069: Henning Petersen: Use prototypes from builtins.h .

Pull up following revision(s) (requested by apb in ticket #570):
	bin/sh/expand.c: revision 1.78
	bin/sh/arith.y: revision 1.18
	bin/sh/expand.h: revision 1.17
	regress/bin/sh/expand.sh: revision 1.4
	bin/sh/sh.1: revision 1.86
	bin/sh/arith_lex.l: revision 1.14
Make /bin/sh use intmax_t (instead of int) for arithmetic in $((...)).

Make /bin/sh use intmax_t (instead of int) for arithmetic in $((...)).

Add new builtin `wordexp' to support wordexp(3).

From FreeBSD.
Provided in PR lib/26123.
Approved by kleink@.

No functional changes (intended).
Rename some variables, add some comments, and restructure a little.
In preparation for fixing "set ${x-a b c}" and friends.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22249, verified by myself.

Fixes from David Laight:
- ansification
- format of output of jobs command (etc)
- job identiers %+, %- etc
- $? and $(...)
- correct quoting of output of set, export -p and readonly -p
- differentiation between nornal and 'posix special' builtins
- correct behaviour (posix) for errors on builtins and special builtins
- builtin printf and kill
- set -o debug (if compiled with DEBUG)
- cd src obj (as ksh - too useful to do without)
- unset -e name, remove non-readonly variable from export list.
  (so I could unset -e PS1 before running the test shell...)

compile with WARNS = 2

PR/7231: Havard Eidnes: Shell quoting/trimming problem

PR/5577: Craig M. Chase: sh does not build with PARALLEL set.
- Added YHEADER in Makefile, removed arith.h and adjusted the sources.

Sync with trunk, per request of christos.

PR/4851: Benjamin Lorenz: In the "for <var> in <args>" construct <args>
was not marked as a region to be handled by ifsbreakup. Add EXP_RECORD
to indicate that the argument string needs to be recorded.

Merge in my changes from vangogh, and fix the x=`false`; echo $? == 0
bug.

convert to new RCS id conventions.

Add RCS ids.

sync with 4.4lite

44lite code

Add RCS identifiers.

changed "Id" to "Header" for rcsids

added rcs ids to all files

initial import of 386bsd-0.1 sources

Initial revision