1.\" Copyright (c) 1996 The NetBSD Foundation, Inc. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to The NetBSD Foundation 5.\" by Paul Kranenburg. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 20.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26.\" POSSIBILITY OF SUCH DAMAGE. 27.\" 28.\" $NetBSD: psignal.9,v 1.1 1996/06/22 22:57:35 pk Exp $ 29.\" $FreeBSD$ 30.\" 31.Dd June 22, 1996 32.Dt PSIGNAL 9 33.Os 34.Sh NAME 35.Nm psignal , 36.Nm pgsignal , 37.Nm gsignal 38.Nd post signal to a process or process group 39.Sh SYNOPSIS 40.In sys/types.h 41.In sys/signalvar.h 42.Ft void 43.Fn psignal "struct proc *p" "int signum" 44.Ft void 45.Fn pgsignal "struct pgrp *pgrp" "int signum" "int checkctty" 46.Ft void 47.Fn gsignal "int pgid" "int signum" 48.Sh DESCRIPTION 49These functions post a signal to one or more processes. 50The argument 51.Fa signum 52common to all three functions should be in the range 53.Bq 1- Ns Dv NSIG . 54.Pp 55The 56.Fn psignal 57function posts signal number 58.Fa signum 59to the process represented by the process structure 60.Fa p . 61With a few exceptions noted below, the target process signal disposition is 62updated and is marked as runnable, so further handling of the signal is done 63in the context of the target process after a context switch. 64Note that 65.Fn psignal 66does not by itself cause a context switch to happen. 67.Pp 68The target process is not marked as runnable in the following cases: 69.Bl -bullet -offset indent 70.It 71The target process is sleeping uninterruptibly. 72The signal will be 73noticed when the process returns from the system call or trap. 74.It 75The target process is currently ignoring the signal. 76.It 77If a stop signal is sent to a sleeping process that takes the 78default action 79(see 80.Xr sigaction 2 ) , 81the process is stopped without awakening it. 82.It 83.Dv SIGCONT 84restarts a stopped process 85(or puts them back to sleep) 86regardless of the signal action 87(e.g., blocked or ignored). 88.El 89.Pp 90If the target process is being traced 91.Fn psignal 92behaves as if the target process were taking the default action for 93.Fa signum . 94This allows the tracing process to be notified of the signal. 95.Pp 96The 97.Fn pgsignal 98function posts signal number 99.Fa signum 100to each member of the process group described by 101.Fa pgrp . 102If 103.Fa checkctty 104is non-zero, the signal will be posted only to processes that have 105a controlling terminal. 106.Fn pgsignal 107is implemented by walking along the process list headed by the field 108.Li pg_members 109of the process group structure 110pointed at by 111.Fa pgrp 112and calling 113.Fn psignal 114as appropriate. 115If 116.Fa pgrp 117is 118.Dv NULL 119no action is taken. 120.Pp 121The 122.Fn gsignal 123function posts signal number 124.Fa signum 125to each member of the process group identified by the group id 126.Fa pgid . 127.Fn gsignal 128first finds the group structure associated with 129.Fa pgid , 130then invokes 131.Fn pgsignal 132with the argument 133.Fa checkctty 134set to zero. 135If 136.Fa pgid 137is zero no action is taken. 138.Sh SEE ALSO 139.Xr sigaction 2 , 140.Xr signal 9 , 141.Xr tsleep 9 142