From 75985d556881bb9e70345418c32d646233d47575 Mon Sep 17 00:00:00 2001
From: "Earle F. Philhower III" <earle@ziplabel.com>
Date: Sun, 11 Mar 2007 01:33:29 +0000
Subject: [PATCH] Check USB handle returned is OK when scanner is opened to
 guard against permission issues or multiple instances accessing the scanner
 at once.

---
 backend/sm3840.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/backend/sm3840.c b/backend/sm3840.c
index 41bdc75ea..6f8abecc3 100755
--- a/backend/sm3840.c
+++ b/backend/sm3840.c
@@ -805,7 +805,10 @@ sane_open (SANE_String_Const devicename, SANE_Handle * handle)
   if (!s)
     return SANE_STATUS_NO_MEM;
 
+  s->udev = 0;
   status = sanei_usb_open (dev->sane.name, &(s->udev));
+  if (!s->udev)
+    return SANE_STATUS_ACCESS_DENIED;
 
   initialize_options_list (s);
   s->scanning = 0;