CVS commit: src/bin/sh

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

Module Name:    src
Committed By:   kre
Date:           Mon Jan 21 14:18:59 UTC 2019

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

Log Message:
When we are about to execute something, and the traps are invalid
(which means this is the very first execution in a new subshell)
clear the traps completely, unless the command is "trap".   We were
allowing any special builtin, which was probably harmless, but not
intended.

Also (though not required) permit "command trap" and "eval trap"
and combinations thereof, because they might be useful, and there is
no particular reason why not.   This is all a part of making t=$(trap)
work as POSIX requires, but almost nothing beyond that.  The "trap"
command must be alone (modulo eval and command) in the subshell for
the exception to apply, no t=$(trap; echo) or anything like that.

Martijn Dekker asked for "command trap" to work (no idea why though,
it converts "trap" from being a special builtin, to a normal one,
which means an error won't cause the shell to exit ... if there's
an error, the "trap" command won't do anything useful, and as we
permit no more commands (for this special treatment) the shell is
going to exit anyway, this difference is not really significant.


To generate a diff of this commit:
cvs rdiff -u -r1.169 -r1.170 src/bin/sh/eval.c

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