[sane-devel] Trouble with sanei_usb change (commit ef5820ce6238469b9946b37e21ec5355edfa520a)

[Stef]

On 27/02/2013 22:10, Stef wrote:
> On 27/02/2013 21:59, Stef wrote:
>> Hello,
>>
>>     the ef5820ce6238469b9946b37e21ec5355edfa520a commit is causing me 
>> troubles.
>> Should we free devname on close ? We can open/close several times the 
>> same device, so I think freeing in sanei_usb_close is problematic. 
>> Reverting this change restored functionality to my backend.
>>
>> Regards,
>>     Stef
>>
>     After further looking at this issue, I think we should add a 
> sanei_usb_exit() function to take care of allocated resources ins 
> sanei_usb_init(). Another case we can free memory is when the device 
> is marked missing (missing field reaching 0).
>
> Regards,
>     Stef
>
>

     Hello,

     regarding the memory leak, the following patch takes care of the 
case where memory is leaked on device that get unplugged or powered off.
      About the few bytes left when a backend exits, what is really 
needed is a sanei_usb_exit function. This function would free allocated 
resources when the last user of sanei_usb_init() calls it.

diff --git a/sanei/sanei_usb.c b/sanei/sanei_usb.c
index cdcca3f..a9696c4 100644
--- a/sanei/sanei_usb.c
+++ b/sanei/sanei_usb.c
@@ -364,8 +364,15 @@ store_device (device_list_type device)
          pos = i;
      }

+  /* reuse slot of a device now missing */
    if(pos > -1){
      DBG (3, "store_device: overwrite dn %d with %s\n", pos, 
device.devname);
+    /* we reuse the slot used by a now missing device
+     * so we free the allocated memory for the missing one */
+    if (devices[pos].devname) {
+      free(devices[pos].devname);
+      devices[pos].devname = NULL;
+    }
    }
    else{
      if(device_number >= MAX_DEVICES){
@@ -2039,10 +2046,6 @@ sanei_usb_close (SANE_Int dn)
      DBG (1, "sanei_usb_close: libusb support missing\n");
  #endif
    devices[dn].open = SANE_FALSE;
-  if (devices[dn].devname) {
-    free(devices[dn].devname);
-    devices[dn].devname = NULL;
-  }
    return;
  }