[PATCH] guard against zero length root

[Markus Linnala]

# HG changeset patch
# User Markus Linnala <Markus.Linnala at cybercom.com>
# Date 1439724126 -10800
#      Sun Aug 16 14:22:06 2015 +0300
# Node ID ca63e42fe06db68c9c85ed5d4140cb682c60d300
# Parent  3b6d69857de22eb03b479223727c365e9035882b
guard against zero length root

diff -r 3b6d69857de2 -r ca63e42fe06d src/http/ngx_http_core_module.c
--- a/src/http/ngx_http_core_module.c	Thu Aug 13 16:27:17 2015 +0300
+++ b/src/http/ngx_http_core_module.c	Sun Aug 16 14:22:06 2015 +0300
@@ -4476,6 +4476,14 @@
     clcf->alias = alias ? clcf->name.len : 0;
     clcf->root = value[1];
 
+    if (clcf->root.len == 0) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "the \"%V\" value can not be empty",
+                           &cmd->name);
+
+        return NGX_CONF_ERROR;
+    }
+
     if (!alias && clcf->root.data[clcf->root.len - 1] == '/') {
         clcf->root.len--;
     }