2 files changed, 11 insertions, 9 deletions

diff --git a/src/sp_upload_validation.c b/src/sp_upload_validation.c
index 794c61f..a8a1340 100644
--- a/src/sp_upload_validation.c
+++ b/src/sp_upload_validation.c
@@ -3,16 +3,15 @@
 
 ZEND_DECLARE_MODULE_GLOBALS(snuffleupagus)
 
+int (*sp_rfc1867_orig_callback)(unsigned int event, void *event_data,
+                                void **extra);
+int sp_rfc1867_callback(unsigned int event, void *event_data, void **extra);
+
 #define EFREE_3(env)               \
   for (size_t i = 0; i < 4; i++) { \
     efree(env[i]);                 \
   }
 
-void hook_upload() {
-  sp_rfc1867_orig_callback = php_rfc1867_callback;
-  php_rfc1867_callback = sp_rfc1867_callback;
-}
-
 int sp_rfc1867_callback(unsigned int event, void *event_data, void **extra) {
   int retval = SUCCESS;
 
@@ -99,3 +98,10 @@ int sp_rfc1867_callback(unsigned int event, void *event_data, void **extra) {
   }
   return retval;
 }
+
+void hook_upload() {
+  if (NULL == sp_rfc1867_orig_callback) {
+    sp_rfc1867_orig_callback = php_rfc1867_callback;
+    php_rfc1867_callback = sp_rfc1867_callback;
+  }
+}
diff --git a/src/sp_upload_validation.h b/src/sp_upload_validation.h
index ae3871b..53790fd 100644
--- a/src/sp_upload_validation.h
+++ b/src/sp_upload_validation.h
@@ -3,8 +3,4 @@
 
 void hook_upload();
 
-int (*sp_rfc1867_orig_callback)(unsigned int event, void *event_data,
-                                void **extra);
-int sp_rfc1867_callback(unsigned int event, void *event_data, void **extra);
-
 #endif