From 6e92fe1e675fa996ed67d9abee17e822e5ed2bbf Mon Sep 17 00:00:00 2001
From: Peter Stamfest <peter@stamfest.at>
Date: Wed, 19 Feb 2014 22:34:20 +0100
Subject: [PATCH] suppress error message from libxml when reading XML from
 stdin. This avoids breakage of the pipe protocol in case of errors.

---
 src/rrd_restore.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/rrd_restore.c b/src/rrd_restore.c
index 1f1924f3..53380dbd 100644
--- a/src/rrd_restore.c
+++ b/src/rrd_restore.c
@@ -1148,6 +1148,17 @@ static int stdioXmlInputCloseCallback(void *context)
     return 0; /* everything is OK */
 }
 
+/* an XML error reporting function that just suppresses all error messages.
+   This is used when parsing an XML file from stdin. This should help to 
+   not break the pipe interface protocol by suppressing the sending out of
+   XML error messages. */
+static void ignoringErrorFunc(
+    void *ctx, 
+    const char * msg, 
+    ...)
+{
+}
+
 static rrd_t *parse_file(
     const char *filename)
 {
@@ -1157,6 +1168,8 @@ static rrd_t *parse_file(
     rrd_t    *rrd;
     stdioXmlReaderContext *sctx = NULL;
 
+    /* special handling for XML on stdin (like it is the case when using
+       the pipe interface) */
     if (strcmp(filename, "-") == 0) {
 	sctx = malloc(sizeof(*sctx));
 	if (sctx == NULL) {
@@ -1168,6 +1181,8 @@ static rrd_t *parse_file(
 	sctx->closed = 0;
 	sctx->eofchar = 0x1A; /* ctrl-Z */
 
+	xmlSetGenericErrorFunc(NULL, ignoringErrorFunc);
+
         reader = xmlReaderForIO(stdioXmlInputReadCallback,
                                 stdioXmlInputCloseCallback,
                                 sctx, 
-- 
2.47.2