CVS commit: src/bin/sh

["Robert Elz" <kre%netbsd.org@localhost>]

Module Name:    src
Committed By:   kre
Date:           Thu Aug 20 23:09:56 UTC 2020

Modified Files:
        src/bin/sh: eval.c trap.c

Log Message:
Be less conservative about when we do clear_traps() when we have
traps_invalid (that is, when we actually nuke the parent shell's
caught traps in a subshell).  This allows more reasonable use of
"trap -p" (and similar) in subshells than existed before (and in
particular, that command can be in a function now - there can also
be several related commands like
        traps=$(trap -p INT; trap -p QUIT; trap -p HUP)
A side effect of all of this is that
        (eval "$(trap -p)"; ...)
now allows copying caught traps into a subshell environment, if desired.

Also att the ksh93 variant (the one not picked by POSIX as it isn't
generally as useful) of "trap -p" (but call it "trap -P" which extracts
just the trap action for named signals (giving more than one is usually
undesirable).   This allows
        eval "$(trap -P INT)"
to run the action for SIGINT traps, without needing to attempt to parse
the "trap -p" output.


To generate a diff of this commit:
cvs rdiff -u -r1.180 -r1.181 src/bin/sh/eval.c
cvs rdiff -u -r1.54 -r1.55 src/bin/sh/trap.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.