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579ad107a6
Upstream commit:
Date: Sun, 11 Nov 2007 15:00:06 +0800
[EXPAND] Removed herefd hack
The herefd hack goes back more than a decade. it limits the amount of
memory we have to allocate when expanding here-documents by writing the
result out from time to time. However, it's no longer safe because the
stack is used to place intermediate results too and there we certainly
don't want to write them out should we be short on memory.
In any case, with today's computers we can afford to keep the entire
result in memory and write them out at the end.
function old new delta
redirect 1268 1264 -4
ash_main 1485 1478 -7
subevalvar 1157 1132 -25
growstackstr 54 24 -30
argstr 1192 1154 -38
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(add/remove: 0/0 grow/shrink: 0/5 up/down: 0/-104) Total: -104 bytes
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.