[EVAL] Force fork if any trap is set, not just on EXIT

In some cases the shell executes a subshell or an external command in
the current process. This is not done if a trap on EXIT has been set, so
that that trap can execute after the subshell or external command has
finished. Extend that check to all traps. (A trap is "set" if a
non-empty command string has been attached to it.)

Improve encapsulation by exporting an accessor function for this and
making the trap array static again.

This is much like FreeBSD SVN r194127, enhanced to apply to subshells
also (see FreeBSD SVN r194774).

Example:
  dash -c '{ trap "echo moo" TERM; sleep 3; }& sleep 1; kill $!;wait'
This should print "moo" after 3 seconds.

Example:
  dash -c '{ trap "echo moo" TERM; (sleep 3) }& sleep 1; kill $!;wait'
The same.

Example:
  dash -c '{ trap "echo moo" TERM; sleep 3; :; }& sleep 1; kill $!;wait'
This works correctly even without this patch.

Signed-off-by: Jilles Tjoelker <jilles@stack.nl>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 4 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 650899a..969d6be 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2010-05-27  Jilles Tjoelker <jilles@stack.nl>
+
+	* Force fork if any trap is set, not just on EXIT.
+
 2010-05-27  Herbert Xu <herbert@gondor.apana.org.au>
 
 	* Fix poplocalvar on abnormal exit from function.