Low: libcib: Avoid memory leak in processing CIB file commit transaction

process_transaction_requests() wasn't freeing output. Do that now.

Also simplify the freeing of output.

* process_request(): Make a copy of *output if it's not in the same doc
  as private->cib_xml. This lets us simplify file_perform_op_delegate().
* process_request(): No operation leaves result_cib set to the same
  value as *output unless it's also equal to private->cib_xml. (A query
  op can do this.) So drop a check in the done section.
* file_perform_op_delegate(): Return only at the end of the function,
  within the done section.
* file_perform_op_delegate(): Don't assign *output_data = NULL at the
  beginning. We'll do this in the done section if output is NULL.
* file_perform_op_delegate(): Assume that output is not in the same
  document as private->cib_xml. We ensured this in process_request().
* file_perform_op_delegate(): Free output if and only if it has not been
  assigned to *output_data.

And do the standard-to-legacy conversion at the end of
file_perform_op_delegate(), in the done section.

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>

Author: nrwahl2

lib/cib/cib_file.c

@@ -191,8 +191,16 @@ process_request(cib_t *cib, xmlNode *request, xmlNode **output)
         set_file_flags(private, file_flag_dirty);
     }
 
+    if (*output == NULL) {
+        goto done;
+    }
+
+    if ((*output)->doc == private->cib_xml->doc) {
+        *output = pcmk__xml_copy(NULL, *output);
+    }
+
 done:
-    if ((result_cib != private->cib_xml) && (result_cib != *output)) {
+    if (result_cib != private->cib_xml) {
         pcmk__xml_free(result_cib);
     }
     pcmk__xml_free(cib_diff);
@@ -226,6 +234,8 @@ process_transaction_requests(cib_t *cib, xmlNode *transaction)
 
         int rc = process_request(cib, request, &output);
 
+        pcmk__xml_free(output);
+
         if (rc != pcmk_rc_ok) {
             pcmk__err("Aborting transaction for CIB file client (%s) on file "
                       "'%s' due to failed %s request: %s",
@@ -403,69 +413,58 @@ file_perform_op_delegate(cib_t *cib, const char *op, const char *host,
 
     const cib__operation_t *operation = NULL;
 
-    pcmk__info("Handling %s operation for %s as %s",
-               pcmk__s(op, "invalid"), pcmk__s(section, "entire CIB"),
+    pcmk__info("Handling %s operation for %s as %s", pcmk__s(op, "invalid"),
+               pcmk__s(section, "entire CIB"),
                pcmk__s(user_name, "default user"));
 
-    if (output_data != NULL) {
-        *output_data = NULL;
-    }
-
     if (cib->state == cib_disconnected) {
-        return -ENOTCONN;
+        rc = ENOTCONN;
+        goto done;
     }
 
     rc = cib__get_operation(op, &operation);
-    rc = pcmk_rc2legacy(rc);
-    if (rc != pcmk_ok) {
+    if (rc != pcmk_rc_ok) {
         // @COMPAT: At compatibility break, use rc directly
-        return -EPROTONOSUPPORT;
+        rc = EPROTONOSUPPORT;
+        goto done;
     }
 
     if (get_op_function(operation) == NULL) {
         // @COMPAT: At compatibility break, use EOPNOTSUPP
         pcmk__err("Operation %s is not supported by CIB file clients", op);
-        return -EPROTONOSUPPORT;
+        rc = EPROTONOSUPPORT;
+        goto done;
     }
 
     cib__set_call_options(call_options, "file operation", cib_no_mtime);
 
     rc = cib__create_op(cib, op, host, section, data, call_options, user_name,
                         NULL, &request);
-    rc = pcmk_rc2legacy(rc);
-    if (rc != pcmk_ok) {
-        return rc;
+    if (rc != pcmk_rc_ok) {
+        goto done;
     }
 
     pcmk__xe_set(request, PCMK__XA_ACL_TARGET, user_name);
     pcmk__xe_set(request, PCMK__XA_CIB_CLIENTID, private->id);
 
     if (pcmk__is_set(call_options, cib_transaction)) {
         rc = cib__extend_transaction(cib, request);
-        rc = pcmk_rc2legacy(rc);
         goto done;
     }
 
     rc = process_request(cib, request, &output);
-    rc = pcmk_rc2legacy(rc);
-
-    if ((output_data != NULL) && (output != NULL)) {
-        if (output->doc == private->cib_xml->doc) {
-            *output_data = pcmk__xml_copy(NULL, output);
-        } else {
-            *output_data = output;
-        }
-    }
 
 done:
-    if ((output != NULL)
-        && (output->doc != private->cib_xml->doc)
-        && ((output_data == NULL) || (output != *output_data))) {
+    pcmk__xml_free(request);
 
+    if (output_data != NULL) {
+        *output_data = output;
+
+    } else {
         pcmk__xml_free(output);
     }
-    pcmk__xml_free(request);
-    return rc;
+
+    return pcmk_rc2legacy(rc);
 }
 
 /*!