[BUILTIN] Make trap signal name/number errors non-fatal.

On Wed, Feb 24, 2010 at 10:23:34AM +0000, Peter Kjellerstedt wrote:
>
> there seems to be a problem  with the trap implementation in dash
> (tested with 0.5.4 and 0.5.5.1). If I specify a signal which is not
> supported, the shell unconditionally aborts. E.g., I had expected
> the following to print foo (like bash and zsh do):
>
> # dash -c 'trap "echo trap executed" UNKNOWNSIGNAL || echo "foo"'
> trap: 1: UNKNOWNSIGNAL: bad trap
>
> This means I cannot write a construct like the following to take
> advantage of the ERR signal which is present in some shells:
>
> trap "echo ERR trap executed" ERR 2>/dev/null || :
>
> I also checked the POSIX documentation, and quoting from
> http://www.opengroup.org/onlinepubs/009695399/utilities/trap.html
> (exit status): "For both interactive and non-interactive shells,
> invalid signal names [XSI] [Option Start] or numbers [Option End]
> shall not be considered a syntax error and do not cause the shell
> to abort."

This patch replaces sh_error with a outfmt + return 1 in trapcmd
so that these errors are no longer fatal.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 4 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index d57ebc1..bc36ab1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2010-04-02  Herbert Xu <herbert@gondor.apana.org.au>
+
+	* Make trap signal name/number errors non-fatal.
+
 2010-04-02  maximilian attems <max@stro.at>
 
 	* Use TMPDIR in mkbuiltins.