Re: bin/57883: Tar opens /dev/(r)fd0* devices on backup hanging when floppy is empty

[Jörg Sonnenberger <joerg%bec.de@localhost>]

The following reply was made to PR bin/57883; it has been noted by GNATS.

From: =?ISO-8859-1?Q?J=F6rg?= Sonnenberger <joerg%bec.de@localhost>
To: gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, gnats-bugs%netbsd.org@localhost
Cc: 
Subject:  Re: bin/57883: Tar opens /dev/(r)fd0* devices on backup hanging when floppy
 is empty
Date: Mon, 29 Jan 2024 01:14:07 +0100

 > >Fix:
 > When formatted floppy is inserted in drive, backup of /dev with tar will finish in acceptable time (however it still tries to access floppy several times).
 > 
 > Expected behaviour: TAR should never open backed block or char devices (should just backup node type, major, minor and permissions), because it may have significant and unexpected side effects - including loss of data.
 
 There is no race free way to get those. There are hundreds of ways to trick
 a program into open a device. It's the fault of the device driver for having
 unusual side effects on open.
 
 Joerg