[PATCH] src/rrd_client.c: Fix a potential segmentation fault in "get_path".

The "get_path" function is called at least from "rrdc_update" without
checking for a connection first. In that case the "sd_path" pointer may be
NULL, so dereferencing it without checking for NULL is not good behavior.

This patch checks all arguments of the "get_path" function and returns an
error if any pointer is NULL.
---
 src/rrd_client.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/src/rrd_client.c b/src/rrd_client.c
index d292281..0d21283 100644
--- a/src/rrd_client.c
+++ b/src/rrd_client.c
@@ -73,6 +73,9 @@ static const char *get_path (const char *path, char *resolved_path) /* {{{ */
   const char *ret = path;
   int is_unix = 0;
 
+  if ((path == NULL) || (resolved_path == NULL) || (sd_path == NULL))
+    return (NULL);
+
   if ((*sd_path == '/')
       || (strncmp ("unix:", sd_path, strlen ("unix:")) == 0))
     is_unix = 1;
-- 
1.5.6.5