virsh: Strip XML declaration when extracting CPU XMLs

Since commit v4.3.0-336-gc84726fbdd all
{hypervisor-,}cpu-{baseline,compare} commands use a generic
vshExtractCPUDefXMLs helper for extracting individual CPU definitions
from the provided input file. The helper wraps the input file in a
<container> element so that several independent elements can be easily
parsed from the file. This works fine except when the file starts with
XML declaration (<?xml version="1.0" ... ?>) because the XML declaration
cannot be put inside any element. In fact it has to be at the very
beginning of the XML document without any preceding white space
characters. We can just simply skip the XML declaration.

https://bugzilla.redhat.com/show_bug.cgi?id=1592737

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

diff --git a/tools/virsh-host.c b/tools/virsh-host.c
index 16f504bafe96fae5259021f7233dc6ae3b00efcc..b7f86bdd91870a1fbad97cf13a88dda8a76f16fe 100644 (file)
--- a/tools/virsh-host.c
+++ b/tools/virsh-host.c
@@ -1130,13 +1130,20 @@ vshExtractCPUDefXMLs(vshControl *ctl,
     xmlDocPtr xml = NULL;
     xmlXPathContextPtr ctxt = NULL;
     xmlNodePtr *nodes = NULL;
+    char *doc;
     size_t i;
     int n;
 
     if (virFileReadAll(xmlFile, VSH_MAX_XML_FILE, &buffer) < 0)
         goto error;
 
-    if (virAsprintf(&xmlStr, "<container>%s</container>", buffer) < 0)
+    /* Strip possible XML declaration */
+    if (STRPREFIX(buffer, "<?xml") && (doc = strstr(buffer, "?>")))
+        doc += 2;
+    else
+        doc = buffer;
+
+    if (virAsprintf(&xmlStr, "<container>%s</container>", doc) < 0)
         goto error;
 
     if (!(xml = virXMLParseStringCtxt(xmlStr, xmlFile, &ctxt)))