4cba3170f9
r283105 misspelled kern_psignal as kernel_psignal in one occurrence, and added trailing whitespace. While here, change 'call' to the more standard 'function', and say why the name was changed (taken from the commit message for r225617).
166 lines
4.5 KiB
Groff
166 lines
4.5 KiB
Groff
.\" Copyright (c) 1996 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Paul Kranenburg.
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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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
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.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $NetBSD: psignal.9,v 1.1 1996/06/22 22:57:35 pk Exp $
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.\" $FreeBSD$
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.\"
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.Dd October 8, 2011
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.Dt PSIGNAL 9
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.Os
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.Sh NAME
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.Nm psignal ,
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.Nm kern_psignal ,
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.Nm pgsignal ,
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.Nm gsignal ,
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.Nm tdsignal
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.Nd post signal to a thread, process, or process group
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.Sh SYNOPSIS
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.In sys/types.h
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.In sys/signalvar.h
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.Ft void
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.Fn kern_psignal "struct proc *p" "int signum"
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.Ft void
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.Fn pgsignal "struct pgrp *pgrp" "int signum" "int checkctty"
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.Ft void
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.Fn gsignal "int pgid" "int signum"
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.Ft void
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.Fn tdsignal "struct thread *td" "int signum"
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.Sh DESCRIPTION
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These functions post a signal to a thread or one or more processes.
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The argument
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.Fa signum
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common to all three functions should be in the range
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.Bq 1- Ns Dv NSIG .
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.Pp
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The
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.Fn kern_psignal
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function posts signal number
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.Fa signum
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to the process represented by the process structure
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.Fa p .
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The
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.Fn kern_psignal
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function used to be called
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.Fn psignal
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but was renamed in order to eliminate a name collision with the libc
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function of that name and facilitate code reuse.
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With a few exceptions noted below, the target process signal disposition is
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updated and is marked as runnable, so further handling of the signal is done
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in the context of the target process after a context switch.
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Note that
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.Fn kern_psignal
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does not by itself cause a context switch to happen.
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.Pp
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The target process is not marked as runnable in the following cases:
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.Bl -bullet -offset indent
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.It
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The target process is sleeping uninterruptibly.
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The signal will be
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noticed when the process returns from the system call or trap.
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.It
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The target process is currently ignoring the signal.
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.It
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If a stop signal is sent to a sleeping process that takes the
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default action
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(see
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.Xr sigaction 2 ) ,
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the process is stopped without awakening it.
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.It
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.Dv SIGCONT
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restarts a stopped process
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(or puts them back to sleep)
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regardless of the signal action
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(e.g., blocked or ignored).
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.El
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.Pp
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If the target process is being traced
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.Fn kern_psignal
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behaves as if the target process were taking the default action for
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.Fa signum .
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This allows the tracing process to be notified of the signal.
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.Pp
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The
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.Fn pgsignal
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function posts signal number
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.Fa signum
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to each member of the process group described by
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.Fa pgrp .
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If
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.Fa checkctty
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is non-zero, the signal will be posted only to processes that have
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a controlling terminal.
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.Fn pgsignal
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is implemented by walking along the process list headed by the field
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.Li pg_members
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of the process group structure
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pointed at by
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.Fa pgrp
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and calling
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.Fn kern_psignal
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as appropriate.
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If
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.Fa pgrp
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is
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.Dv NULL
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no action is taken.
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.Pp
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The
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.Fn gsignal
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function posts signal number
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.Fa signum
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to each member of the process group identified by the group id
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.Fa pgid .
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.Fn gsignal
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first finds the group structure associated with
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.Fa pgid ,
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then invokes
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.Fn pgsignal
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with the argument
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.Fa checkctty
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set to zero.
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If
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.Fa pgid
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is zero no action is taken.
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.Pp
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The
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.Fn tdsignal
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function posts signal number
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.Fa signum
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to the thread represented by the thread structure
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.Fa td .
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.Sh SEE ALSO
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.Xr sigaction 2 ,
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.Xr signal 9 ,
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.Xr tsleep 9
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.Sh HISTORY
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The
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.Fn psignal
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function was renamed to
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.Fn kern_psignal
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in
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.Fx 9.0 .
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