From owner-freebsd-hackers  Tue Dec 15 13:42:15 1998
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Date: Tue, 15 Dec 1998 15:41:46 -0600
From: Dan Nelson <dnelson@emsphone.com>
To: Matthew Dillon <dillon@apollo.backplane.com>,
        David Wolfskill <dhw@whistle.com>
Cc: ambrisko@whistle.com, hackers@FreeBSD.ORG
Subject: Re: bin/8183
Message-ID: <19981215154146.A46153@emsphone.com>
References: <199812151945.LAA09463@pau-amma.whistle.com> <199812151950.LAA59883@apollo.backplane.com>
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In the last episode (Dec 15), Matthew Dillon said:
>     I wonder... does exec() clear blocked signals?  I assumed it did.
>     Anyone know for sure?

It does not.  manpage for signal(3):

     When a process which has installed signal handlers forks, the
     child process inherits the signals.  All caught signals may be
     reset to their default action by a call to the execve(2) function;
     ignored signals remain ignored.

Note that this affects any background program run via "nohup" also.  If
you run "nohup program &", don't expect to be able to kill -HUP it
later.  This was discussed a little on the mysql mailinglist, when
FreeBSD people noticed that they couldn't kill the server (mysql uses
-QUIT to exit, and nohup blocks HUP and QUIT).

	-Dan Nelson
	dnelson@emsphone.com

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