216913c290
This closes 10821.
Upstream patch:
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 9 Mar 2018 00:14:02 +0800
parser: Add syntax stack for recursive parsing
Without a stack of syntaxes we cannot correctly these two cases
together:
"${a#'$$'}"
"${a#"${b-'$$'}"}"
A recursive parser also helps in some other corner cases such
as nested arithmetic expansion with paratheses.
This patch adds a syntax stack allocated from the stack using
alloca. As a side-effect this allows us to remove the naked
backslashes for patterns within double-quotes, which means that
EXP_QPAT also has to go.
This patch also fixes removes any backslashes that precede right
braces when they are present within a parameter expansion context,
and backslashes that precede double quotes within inner double
quotes inside a parameter expansion in a here-document context.
The idea of a recursive parser is based on a patch by Harald van
Dijk.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
var_bash3, var_bash4 and var_bash6 tests are updated
with the output given by bash-4.3.43
With this patch, the following tests now pass for ash:
dollar_repl_slash_bash2.tests
squote_in_varexp2.tests
squote_in_varexp.tests
var_bash4.tests
function old new delta
readtoken1 2615 2874 +259
synstack_push - 54 +54
evalvar 574 571 -3
rmescapes 330 310 -20
subevalvar 1279 1258 -21
argstr 1146 1107 -39
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/4 up/down: 313/-83) Total: 230 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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.