From owner-freebsd-standards@FreeBSD.ORG  Tue Mar 22 18:34:54 2011
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Date: Tue, 22 Mar 2011 14:16:04 -0400
From: David Schultz <das@FreeBSD.ORG>
To: Chris Rees <utisoft@gmail.com>
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	Oliver Fromme <olli@lurza.secnetix.de>
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Cc: Oliver Fromme <olli@lurza.secnetix.de>,
	Maxim Konovalov <maxim.konovalov@gmail.com>, freebsd-standards@FreeBSD.ORG
Subject: Re: dd dies on SIGUSR1
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On Tue, Mar 22, 2011, Chris Rees wrote:
> Since POSIX has SIGUSR[12] as undefined, I think it's a POLA violation
> to have processes die when provided.

Quite the contrary: The default behavior of SIGUSR1 on FreeBSD
follows both POSIX and historical precedent, so changing it would
be a violation of POLA.  Terminating the process is also the
default on Linux.

Linux dd's interpretation of SIGUSR1 seems rather poorly
considered, since as you note, utilities that don't handle it will
simply die unexpectedly.  However, it certainly wouldn't hurt to
patch FreeBSD's dd to handle SIGUSR1 the same way as SIGINFO.