1996-08-19 02:22:15 +00:00
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.\"
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.\" Copyright (c) 1996 Julian Elischer
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.\"
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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1997-04-13 14:49:13 +00:00
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.\" $Id: at_fork.9,v 1.5 1997/02/22 13:26:22 peter Exp $
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1996-08-19 02:22:15 +00:00
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.\" "
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.Dd August 15, 1996
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.Os
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.Dt AT_FORK 9
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.Sh NAME
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.Nm at_fork ,
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.Nm rm_at_fork
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.Nd ask that a function be run at fork.
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.Sh SYNOPSIS
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1997-04-13 14:49:13 +00:00
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.Fd #include <sys/types.h>
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1996-08-19 02:22:15 +00:00
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.Fd #include <sys/systm.h>
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.Ft typedef void \*(lp*forklist_fn\*(rp \*(lpstruct proc*, struct proc*, int\*(rp;
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1997-04-13 14:49:13 +00:00
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.Ft int
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1996-08-19 02:22:15 +00:00
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.Fn at_fork "forklist_fn func"
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1997-04-13 14:49:13 +00:00
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.Ft int
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1996-08-19 02:22:15 +00:00
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.Fn rm_at_fork "forklist_fn func"
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.Sh DESCRIPTION
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The
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.Nm at_fork
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facility allows a kernel module to ensure that it is notified
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at any process fork.
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The function
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1997-02-14 07:47:37 +00:00
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.Fa func
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1996-08-19 02:22:15 +00:00
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is called with the a pointer to the forking process's proc structure,
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a pointer to the child's process structure and a flag word,
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as used in
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.Xr rfork 2
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to indicate the type of fork.
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.Pp
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If the requirement for notification is removed, then the function
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1997-02-14 07:47:37 +00:00
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.Fn rm_at_fork
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1996-08-19 02:22:15 +00:00
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must be called with the exact
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1997-02-14 07:47:37 +00:00
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.Fa func
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1996-08-19 02:22:15 +00:00
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argument as the corresponding call to
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.Fn at_fork .
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.Pp
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.Sh RETURN VALUES
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1997-02-14 07:47:37 +00:00
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.Fn at_fork
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1996-08-19 02:22:15 +00:00
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returns an errno, 0 meaning success.
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1997-02-14 07:47:37 +00:00
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.Fn rm_at_fork
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1996-08-19 02:22:15 +00:00
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returns the number of items removed (should be 0 or 1).
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.Sh SEE ALSO
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.Xr fork 2
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.Sh HISTORY
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The
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1997-02-14 07:47:37 +00:00
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.Fn at_fork
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function appeared in
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1996-08-21 21:43:28 +00:00
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.Fx 2.2 .
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1996-08-19 02:22:15 +00:00
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.Sh BUGS
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Since the fork queue is not sorted
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and items are added to the head, order of execution
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is reversed to that of insertion.
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.Sh AUTHORS
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The function was written by
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.ie Julian Elischer (julian@freebsd.org)
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.el Julian Elischer (julian@freebsd.org)
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