1555895b4a
Upstream commit: Date: Wed, 12 Sep 2018 14:27:16 +0800 expand: Fix multiple issues with EXP_DISCARD in evalvar The commit 3cd538634f71538370f5af239f342aec48b7470b broke parameter expansion in multiple ways because the EXP_DISCARD flag wasn't set or tested for various cases: $ src/dash -c 'var=; echo ${var:+nonempty}' nonempty $ src/dash -u -c 'unset foo bar; echo ${foo+${bar}}' dash: 1: bar: parameter not set $ src/dash -c 'foo=bar; echo ${foo=BUG}; echo $foo' barBUG bar $ This patch fixes them by introducing a new discard variable that tracks whether the extra word should be discarded or not when it is parsed. Reported-by: Martijn Dekker <martijn@inlv.org> Fixes: 3cd538634f71 ("expand: Do not reprocess data when...") Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Reported-by: Martijn Dekker <martijn@inlv.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> |
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ash_test | ||
hush_test | ||
ash_doc.txt | ||
ash_ptr_hack.c | ||
ash.c | ||
brace.txt | ||
Config.src | ||
cttyhack.c | ||
hush_doc.txt | ||
hush_leaktool.sh | ||
hush.c | ||
Kbuild.src | ||
match.c | ||
match.h | ||
math.c | ||
math.h | ||
random.c | ||
random.h | ||
README | ||
README.job | ||
shell_common.c | ||
shell_common.h |
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.