www: fix PHP internal error (500) while flashing

userspace/rootfs_override/var/www/functions.php

@@ -778,6 +778,8 @@ function wrs_management(){
 		if (!strcmp($cmd, "reboot")){
 			wrs_reboot();
 		} else if (!empty($_FILES['firmware']['name'])){
+			shell_exec("rm /tmp/wrs-firmware.tar"); //Clean previously uploaded files
+			shell_exec("rm /tmp/wr-switch-sw-v*_binaries.tar"); //Clean previously uploaded files
 			$uploaddir = '/tmp/';
 			$uploadfname= basename($_FILES['firmware']['name']);
 			$uploadfile = $uploaddir . $uploadfname;
@@ -786,14 +788,14 @@ function wrs_management(){
 				echo '<p align=center ><font color="red"><br>Upgrade procedure will take place after reboot.<br>Please do not switch off the device during flashing procedure.</font></p>';
 				if ($uploadfname=="barebox.bin" || $uploadfname=="wrs-firmware.tar" || $uploadfname=="zImage")
 				{
-					rename($uploadfile, "/update/".($_FILES['firmware']['name']));
+					shell_exec("mv -f $uploadfile /update/".($_FILES['firmware']['name']));
 					//Reboot switch
 					sleep(1);
 					wrs_reboot(90); //Updating only one part of the firmware take ~90s.
 				}
 				else if(substr($uploadfname,0,14)=="wr-switch-sw-v" && substr($uploadfname,-13)=="_binaries.tar")
 				{
-					rename($uploadfile, "/update/wrs-firmware.tar");
+					shell_exec("mv -f $uploadfile /update/wrs-firmware.tar");
 					//Reboot switch
 					sleep(1);
 					wrs_reboot(150); //120s should be enough but we prefer to keep safe