Xen4.1 initializes some unspecified sexpr config items to an empty
string, unlike previous Xen versions that would leave the item unset.
E.g. the kernel item for an HVM guest (non-direct kernel boot):
Xen4.0 and earlier
...
(image
(hvm
(kernel )
...
Xen4.1
...
(image
(hvm
(kernel '')
...
The empty string for kernel causes some grief in subsequent parsing
where existence of specified kernel is checked, e.g.
if (!def->os.kernel)
...
This patch solves the problem in sexpr_node_copy() by not copying
a node containing an empty string.
---
src/util/sexpr.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/src/util/sexpr.c b/src/util/sexpr.c
index 0e30087..3523d76 100644
--- a/src/util/sexpr.c
+++ b/src/util/sexpr.c
@@ -519,7 +519,7 @@ int sexpr_node_copy(const struct sexpr *sexpr, const char *node, char
**dst)
{
const char *val = sexpr_node(sexpr, node);
- if (val) {
+ if (val && *val) {
*dst = strdup(val);
if (!(*dst))
return -1;
--
1.7.7