[OpenBIOS] [PATCH] mac-parts.c: Fix /packages/mac-parts boot when the package arguments are empty.

[Mark Cave-Ayland]

Commit r1072 removed a couple of NULL pointer checks for package arguments,
however if the arguments are empty in Forth then they are converted back to a
NULL pointer which causes an exception when dereferenced.

Add the checks back in which fixes boot of the debian_lenny_powerpc_small.qcow2
test image with quik once again. Based upon an earlier patch by Alexander Graf
<agraf at suse.de>.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland at ilande.co.uk>
CC: Alexander Garf <agraf at suse.de>
---
 openbios-devel/packages/mac-parts.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/openbios-devel/packages/mac-parts.c b/openbios-devel/packages/mac-parts.c
index d0cba05..12c94e5 100644
--- a/openbios-devel/packages/mac-parts.c
+++ b/openbios-devel/packages/mac-parts.c
@@ -68,7 +68,7 @@ macparts_open( macparts_info_t *di )
 		[(id)][,][filespec]
 	*/
 	
-	if ( strlen(str) ) {
+	if ( str && strlen(str) ) {
 		/* Detect the arguments */
 		if ((*str >= '0' && *str <= '9') || (*str == ',')) {
 		    push_str(str);
@@ -126,7 +126,7 @@ macparts_open( macparts_info_t *di )
 	 * Implement partition selection as per the PowerPC Microprocessor CHRP bindings
 	 */
 
-	if (parnum == 0) {
+	if (str == NULL || parnum == 0) {
 		/* According to the spec, partition 0 as well as no arguments means the whole disk */
 		offs = (long long)0;
 		size = (long long)__be32_to_cpu(dmap.sbBlkCount) * bs;
-- 
1.7.10.4