Commit Graph

20 Commits

Author SHA1 Message Date
jilles
cd2fb30b68 sh: Make expari() static. 2014-02-26 21:38:42 +00:00
jilles
6fa139d56e sh: Expand here documents in the current process.
Expand here documents at the same point other redirections are expanded but
use a non-fork subshell environment (like simple command substitutions) for
compatibility. Substitition errors result in an empty here document like
before.

As a result, a fork is avoided for short (<4K) expanded here documents.

Unexpanded here documents (with quoted end marker after <<) are not affected
by this change. They already only forked when >4K.

Side effects:
* Order of expansion is slightly different.
* Slow expansions are not executed in parallel with the redirected command.
* A non-fork subshell environment is subtly different from a forked process.
2013-02-03 15:54:57 +00:00
jilles
8152f4c192 sh: Make various functions static. 2012-01-01 22:17:12 +00:00
jilles
16addb8673 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.
2011-06-13 21:03:27 +00:00
jilles
91789615b4 sh: Save/restore changed variables in optimized command substitution.
In optimized command substitution, save and restore any variables changed by
expansions (${var=value} and $((var=assigned))), instead of trying to
determine if an expansion may cause such changes.

If $! is referenced in optimized command substitution, do not cause jobs to
be remembered longer.

This fixes $(jobs $!) again, simplifies the man page and shortens the code.
2011-06-12 23:06:04 +00:00
jilles
74d9b02bb0 sh: Don't do optimized command substitution if expansions have side effects.
Before considering to execute a command substitution in the same process,
check if any of the expansions may have a side effect; if so, execute it in
a new process just like happens if it is not a single simple command.

Although the check happens at run time, it is a static check that does not
depend on current state. It is triggered by:
- expanding $! (which may cause the job to be remembered)
- ${var=value} default value assignment
- assignment operators in arithmetic
- parameter substitutions in arithmetic except ${#param}, $$, $# and $?
- command substitutions in arithmetic

This means that $((v+1)) does not prevent optimized command substitution,
whereas $(($v+1)) does, because $v might expand to something containing
assignment operators.

Scripts should not depend on these exact details for correctness. It is also
imaginable to have the shell fork if and when a side effect is encountered
or to create a new temporary namespace for variables.

Due to the $! change, the construct $(jobs $!) no longer works. The value of
$! should be stored in a variable outside command substitution first.
2010-12-28 21:27:08 +00:00
jilles
28ad180ab4 sh: Do IFS splitting on word in ${v+word} and ${v-word}.
The code is inspired by NetBSD sh somewhat, but different because we
preserve the old Almquist/Bourne/Korn ability to have an unquoted part in a
quoted ${v+word}. For example, "${v-"*"}" expands to $v as a single field if
v is set, but generates filenames otherwise.

Note that this is the only place where we split text literally from the
script (the similar ${v=word} assigns to v and then expands $v). The parser
must now add additional markers to allow the expansion code to know whether
arbitrary characters in substitutions are quoted.

Example:
  for i in ${$+a b c}; do echo $i; done

Exp-run done by:	pav (with some other sh(1) changes)
2010-10-29 13:42:18 +00:00
jilles
8e458de852 sh: Constify various strings.
Most of this is adding const keywords, but setvar() in var.c had to be
changed somewhat more.
2009-12-24 18:41:14 +00:00
markm
4383f14801 Remove clause 3 from the UCB licenses.
OK'ed by:	imp, core
2004-04-06 20:06:54 +00:00
tjr
3b9687df3d Add the "wordexp" shell built-in command which will be used to implement
the POSIX wordexp() function.
2002-12-26 14:28:54 +00:00
imp
5ef5088ac4 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)
	{
	...
2002-02-02 06:50:57 +00:00
peter
66312e4a8d $Id$ -> $FreeBSD$ 1999-08-27 23:15:48 +00:00
tegge
e35119550e When a variable expansion is enclosed in double quotes, the internal
representation of the expression is quoted.  Take care of this when
doing pattern matching in conjunction with trimming.

	#!/bin/sh
	c=d:e; echo "${c%:e}"

PR:		NetBSD PR#7231
Noticed by:	Havard Eidnes <Havard.Eidnes@runit.sintef.no>
1999-04-09 15:23:48 +00:00
tegge
c82e121ce7 Be more consistent with handling of quote mark control character.
Don't output double-quotes inside variable expansion/arithmetic
expansion region in here-documents.  When leaving the arithmetic
expansion syntax mode, adjust the dblquote flag according to
previous syntax, in order to avoid splitting of quoted variables.
1998-09-13 19:24:57 +00:00
tegge
ac59a0c5cd Better handling of word splitting. Don't record the same region
multiple times when performing nested variable expansion, and
preserve some quoting information in order to avoid removing
apparently empty expansion result.
1998-09-06 21:13:09 +00:00
peter
83b3c2c161 Revert $FreeBSD$ to $Id$ 1997-02-22 14:13:04 +00:00
jkh
808a36ef65 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.
1997-01-14 07:20:47 +00:00
peter
5195be912e 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
1996-09-01 10:22:36 +00:00
dg
8722740e7f Added $Id$ 1994-09-24 02:59:15 +00:00
rgrimes
e3cfc8ce61 BSD 4.4 Lite bin Sources 1994-05-26 06:18:55 +00:00