Tcl exception codes cleanup, shutdown command amendments

This patch might influence openocd Tcl commands behaviour in subtle
ways, please give it a nice testing.

The idea is that if an OpenOCD Tcl command returns an error, an
exception is raised, and then the return code is propogated all the
way up (or to the "catch" if present). This allows to detect
"shutdown" which is not actually an error but has to raise an
exception to stop execution of the commands that follow it in the
script.

openocd_thread special-cases shutdown because it should then terminate
OpenOCD with a success error code, unless shutdown was called with an
optional "error" argument which means terminate with a non-zero exit
code.

Change-Id: I7b6fa8a2e24c947dc45d8def0008b4b007c478b3
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/2600
Tested-by: jenkins
Reviewed-by: Juha Niskanen <juha.niskanen@haltian.com>
Reviewed-by: Jens Bauer <jens@gpio.dk>
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/helper/startup.tcl b/src/helper/startup.tcl
index 926d26b6..4ca2cabc 100644
--- a/src/helper/startup.tcl
+++ b/src/helper/startup.tcl
@@ -16,10 +16,12 @@ proc exit {} {
 proc ocd_bouncer {name args} {
 	set cmd [format "ocd_%s" $name]
 	set type [eval ocd_command type $cmd $args]
+	set errcode error
 	if {$type == "native"} {
 		return [eval $cmd $args]
 	} else {if {$type == "simple"} {
-		if {[catch {eval $cmd $args}] == 0} {
+		set errcode [catch {eval $cmd $args}]
+		if {$errcode == 0} {
 			return ""
 		} else {
 			# 'classic' commands output error message as part of progress output
@@ -32,7 +34,7 @@ proc ocd_bouncer {name args} {
 	} else {
 		set errmsg [format "invalid subcommand \"%s\"" $args]
 	}}}
-	return -code error $errmsg
+	return -code $errcode $errmsg
 }
 
 # Try flipping / and \ to find file if the filename does not