675d24aeaf
This patch is a backport from dash of the combination of:
[SHELL] Add preliminary LINENO support
[VAR] Fix varinit ordering that broke fc
[SHELL] Improve LINENO support
function old new delta
parse_command 1604 1677 +73
calcsize 156 223 +67
copynode 196 258 +62
evalcommand 1546 1606 +60
ash_main 1046 1103 +57
lookupvar 51 106 +55
evalcase 269 317 +48
evaltree 501 547 +46
evalfor 156 200 +44
evalsubshell 156 195 +39
raise_error_syntax 11 29 +18
varinit_data 120 132 +12
evalfun 270 280 +10
funcline - 4 +4
cmdtxt 569 572 +3
trapcmd 306 304 -2
ash_vmsg 153 150 -3
startlinno 4 - -4
funcnest 4 - -4
xxreadtoken 263 250 -13
readtoken1 2645 2602 -43
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(add/remove: 1/2 grow/shrink: 14/4 up/down: 598/-69) Total: 529 bytes
text data bss dec hex filename
932834 481 6864 940179 e5893 busybox_old
933375 481 6856 940712 e5aa8 busybox_unstripped
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.