9d6cbafe72
With new version of signal handling, read builtin should be less buggy wrt signals. function old new delta install_sighandlers - 121 +121 switch_off_special_sigs - 84 +84 pick_sighandler - 58 +58 install_special_sighandlers - 47 +47 builtin_wait 284 319 +35 record_pending_signo - 21 +21 execvp_or_die 43 48 +5 file_get 290 288 -2 run_list 1004 998 -6 static.zero_timespec 8 - -8 sigprocmask_set 14 - -14 sigwaitinfo 23 - -23 record_signal 23 - -23 __GI_sigwaitinfo 23 - -23 sigtimedwait 25 - -25 builtin_trap 417 392 -25 __GI_sigtimedwait 25 - -25 hush_main 1003 965 -38 check_and_run_traps 263 217 -46 __rt_sigtimedwait 52 - -52 reset_traps_to_defaults 213 126 -87 init_sigmasks 198 - -198 builtin_read 536 197 -339 ------------------------------------------------------------------------------ (add/remove: 5/10 grow/shrink: 2/7 up/down: 371/-934) Total: -563 bytes text data bss dec hex filename 903075 936 17736 921747 e1093 busybox_old 902547 936 17736 921219 e0e83 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> |
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.. | ||
ash_test | ||
hush_test | ||
msh_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.