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Denys Vlasenko 8c68ae8416 ash: parser: Fix alias expansion after heredoc or newlines 
Upstream commit:

    Date: Wed, 29 Apr 2020 00:19:59 +1000
    parser: Fix alias expansion after heredoc or newlines

    This script should print OK:

        alias a="case x in " b=x
        a
        b) echo BAD;; esac

        alias BEGIN={ END=}
        BEGIN
    	cat <<- EOF > /dev/null
    		$(:)
    	EOF
        END
        : <<- EOF &&
    		$(:)
        EOF
        BEGIN
    	echo OK
        END

    However, because the value of checkkwd is either zeroed when it
    shouldn't, or isn't zeroed when it should, dash currently gets
    it wrong in every case.

    This patch fixes it by saving checkkwd and zeroing it where needed.

function                                             old     new   delta
readtoken                                            157     176     +19

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-09-08 01:43:12 +02:00
..
ash_test ash: parser: Fix alias expansion after heredoc or newlines 2021-09-08 01:43:12 +02:00
hush_test ash: LINENO starts from 0 in -c SCRIPT mode 2021-09-07 18:16:45 +02:00
ash_doc.txt ash: fix TRACE commands 2009-03-19 23:09:58 +00:00
ash_ptr_hack.c *: make GNU licensing statement forms more regular 2010-08-16 20:14:46 +02:00
ash_remove_unnecessary_code_in_backquote_expansion.patch ash: save Ron's patch from oblivion 2021-06-06 13:01:25 +02:00
ash.c ash: parser: Fix alias expansion after heredoc or newlines 2021-09-08 01:43:12 +02:00
brace.txt hush: wait for cmd to complete, and immediately store its exitcode in $? 2009-11-15 19:58:19 +01:00
Config.src nologin: make it possible to build it as single applet 2020-06-24 15:05:22 +02:00
cttyhack.c config: update size information 2018-12-28 03:20:17 +01:00
hush_doc.txt hush: implement break and continue 2008-07-28 23:04:34 +00:00
hush_leaktool.sh hush: fix "export not_yet_defined_var", fix parsing of "cmd | }" 2009-04-19 23:07:51 +00:00
hush.c hush: fix var_LINENO3.tests failure 2021-09-07 21:44:44 +02:00
Kbuild.src Make it possible to select "sh" and "bash" aliases without selecting ash or hush 2016-12-23 16:56:43 +01:00
match.c hush: optimize ${var/pattern/repl} for trivial patterns 2021-07-27 17:53:55 +02:00
match.h hush: optimize #[#] and %[%] for speed. size -2 bytes. 2010-09-04 21:21:07 +02:00
math.c shell: remove FAST_FUNC from a static function 2020-10-01 00:57:05 +02:00
math.h shell: move all definitions of strto_arith_t() together 2019-05-26 14:02:10 +02:00
random.c whitespace fixes 2018-07-17 15:04:17 +02:00
random.h ash,hush: improve randomness of $RANDOM, add easy-ish way to test it 2014-03-13 12:52:43 +01:00
README update shell/README 2010-05-20 12:56:14 +02:00
README.job
shell_common.c shells: do not allow bare "read" in non-bash compat configs 2021-06-06 12:08:43 +02:00
shell_common.h hush: fix "export PS1=xyz" and "local PS1=xyz" messing up prompt 2019-05-14 18:56:04 +02:00

README 

http://www.opengroup.org/onlinepubs/9699919799/
Open Group Base Specifications Issue 7


http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap01.html
Shell & Utilities

It says that any of the standard utilities may be implemented
as a regular shell built-in. It gives a list of utilities which
are usually implemented that way (and some of them can only
be implemented as built-ins, like "alias"):

alias
bg
cd
command
false
fc
fg
getopts
jobs
kill
newgrp
pwd
read
true
umask
unalias
wait


http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
Shell Command Language

It says that shell must implement special built-ins. Special built-ins
differ from regular ones by the fact that variable assignments
done on special builtin are *PRESERVED*. That is,

VAR=VAL special_builtin; echo $VAR

should print VAL.

(Another distinction is that an error in special built-in should
abort the shell, but this is not such a critical difference,
and moreover, at least bash's "set" does not follow this rule,
which is even codified in autoconf configure logic now...)

List of special builtins:

. file
: [argument...]
break [n]
continue [n]
eval [argument...]
exec [command [argument...]]
exit [n]
export name[=word]...
export -p
readonly name[=word]...
readonly -p
return [n]
set [-abCefhmnuvx] [-o option] [argument...]
set [+abCefhmnuvx] [+o option] [argument...]
set -- [argument...]
set -o
set +o
shift [n]
times
trap n [condition...]
trap [action condition...]
unset [-fv] name...

In practice, no one uses this obscure feature - none of these builtins
gives any special reasons to play such dirty tricks.

However. This section also says that *function invocation* should act
similar to special built-in. That is, variable assignments
done on function invocation should be preserved after function invocation.

This is significant: it is not unthinkable to want to run a function
with some variables set to special values. But because of the above,
it does not work: variable will "leak" out of the function.