[netcf-devel] [PATCH] Fix conversion of XML DOM's into strings

[David Lutterkort]

We should not use xmlDocDumpFormatMemory to convert a DOM we got from
applying a stylesheet to a string; the proper API to use is
xsltSaveResultToString.

  * src/dutil.h (apply_stylesheet_to_string): new function
  * src/dutil.c (apply_stylesheet_to_string): new function
  * src/dutil.c (dutil_get_aug, dutil_put_aug): use
    apply_stylesheet_to_string
  * src/drv_initscripts.c (drv_xml_desc): use apply_stylesheet_to_string
---
 src/drv_initscripts.c |    6 +++---
 src/dutil.c           |   30 ++++++++++++++++++++++++------
 src/dutil.h           |    5 +++++
 3 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/src/drv_initscripts.c b/src/drv_initscripts.c
index b9ef03c..3da9209 100644
--- a/src/drv_initscripts.c
+++ b/src/drv_initscripts.c
@@ -43,6 +43,7 @@
 #include <libxslt/xslt.h>
 #include <libxslt/xsltInternals.h>
 #include <libxslt/transform.h>
+#include <libxslt/xsltutils.h>
 
 static const char *const ifcfg_path =
     "/files/etc/sysconfig/network-scripts/*";
@@ -498,10 +499,9 @@ char *drv_xml_desc(struct netcf_if *nif) {
     ERR_BAIL(ncf);
 
     aug_xml = aug_get_xml(ncf, nint, intf);
-    ncf_xml = apply_stylesheet(ncf, ncf->driver->put, aug_xml);
-    ERR_BAIL(ncf);
 
-    xmlDocDumpFormatMemory(ncf_xml, (xmlChar **) &result, NULL, 1);
+    result = apply_stylesheet_to_string(ncf, ncf->driver->put, aug_xml);
+    ERR_BAIL(ncf);
 
  done:
     free_matches(nint, &intf);
diff --git a/src/dutil.c b/src/dutil.c
index 993f715..9c1481e 100644
--- a/src/dutil.c
+++ b/src/dutil.c
@@ -238,6 +238,28 @@ error:
     xsltFreeTransformContext(ctxt);
     return res;
 }
+
+char *apply_stylesheet_to_string(struct netcf *ncf, xsltStylesheetPtr style,
+                                 xmlDocPtr doc) {
+    xmlDocPtr doc_xfm = NULL;
+    char *result = NULL;
+    int r, result_len;
+
+    doc_xfm = apply_stylesheet(ncf, style, doc);
+    ERR_BAIL(ncf);
+
+    r = xsltSaveResultToString((xmlChar **) &result, &result_len,
+                               doc_xfm, style);
+    ERR_COND_BAIL(r < 0, ncf, ENOMEM);
+    xmlFree(doc_xfm);
+    return result;
+
+ error:
+    FREE(result);
+    xmlFreeDoc(doc_xfm);
+    return NULL;
+}
+
 /* Callback for reporting RelaxNG errors */
 void rng_error(void *ctx, const char *format, ...) {
     struct netcf *ncf = ctx;
@@ -392,11 +414,9 @@ int dutil_get_aug(struct netcf *ncf, const char *ncf_xml, char
**aug_xml) {
     rng_validate(ncf, ncf_doc);
     ERR_BAIL(ncf);
 
-    aug_doc = apply_stylesheet(ncf, ncf->driver->get, ncf_doc);
+    *aug_xml = apply_stylesheet_to_string(ncf, ncf->driver->get, ncf_doc);
     ERR_BAIL(ncf);
 
-    xmlDocDumpFormatMemory(aug_doc, (xmlChar **) aug_xml, NULL, 1);
-    ERR_COND_BAIL(*aug_xml == NULL, ncf, EXMLINVALID);
     /* fallthrough intentional */
     result = 0;
  error:
@@ -413,11 +433,9 @@ int dutil_put_aug(struct netcf *ncf, const char *aug_xml, char
**ncf_xml) {
     aug_doc = parse_xml(ncf, aug_xml);
     ERR_BAIL(ncf);
 
-    ncf_doc = apply_stylesheet(ncf, ncf->driver->put, aug_doc);
+    *ncf_xml = apply_stylesheet_to_string(ncf, ncf->driver->put, aug_doc);
     ERR_BAIL(ncf);
 
-    xmlDocDumpFormatMemory(ncf_doc, (xmlChar **) ncf_xml, NULL, 1);
-    ERR_COND_BAIL(*ncf_xml == NULL, ncf, EXMLINVALID);
     /* fallthrough intentional */
     result = 0;
  error:
diff --git a/src/dutil.h b/src/dutil.h
index fbf11fb..38aec5f 100644
--- a/src/dutil.h
+++ b/src/dutil.h
@@ -68,6 +68,11 @@ xsltStylesheetPtr parse_stylesheet(struct netcf *ncf, const char
*fname);
 xmlDocPtr apply_stylesheet(struct netcf *ncf, xsltStylesheetPtr style,
                            xmlDocPtr doc);
 
+/* Same as APPLY_STYLESHEET, but convert the resulting XML document into a
+ * string */
+char *apply_stylesheet_to_string(struct netcf *ncf, xsltStylesheetPtr style,
+                                 xmlDocPtr doc);
+
 /* Callback for reporting RelaxNG errors */
 void rng_error(void *ctx, const char *format, ...);
 
-- 
1.6.2.5