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.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the NetBSD 18.\" Foundation, Inc. and its contributors. 19.\" 4. Neither the name of The NetBSD Foundation nor the names of its 20.\" contributors may be used to endorse or promote products derived 21.\" from this software without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 24.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 27.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33.\" POSSIBILITY OF SUCH DAMAGE. 34.\" 35.\" $NetBSD: psignal.9,v 1.1 1996/06/22 22:57:35 pk Exp $ 36.\" $FreeBSD$ 37.\" 38.Dd June 22, 1996 39.Dt PSIGNAL 9 40.Os 41.Sh NAME 42.Nm psignal , 43.Nm pgsignal , 44.Nm gsignal 45.Nd post signal to a process or process group 46.Sh SYNOPSIS 47.In sys/types.h 48.In sys/signalvar.h 49.Ft void 50.Fn psignal "struct proc *p" "int signum" 51.Ft void 52.Fn pgsignal "struct pgrp *pgrp" "int signum" "int checkctty" 53.Ft void 54.Fn gsignal "int pgid" "int signum" 55.Sh DESCRIPTION 56These functions post a signal to one or more processes. 57The argument 58.Fa signum 59common to all three functions should be in the range 60.Bq 1- Ns Dv NSIG . 61.Pp 62The 63.Fn psignal 64function posts signal number 65.Fa signum 66to the process represented by the process structure 67.Fa p . 68With a few exceptions noted below, the target process signal disposition is 69updated and is marked as runnable, so further handling of the signal is done 70in the context of the target process after a context switch. 71Note that 72.Fn psignal 73does not by itself cause a context switch to happen. 74.Pp 75The target process is not marked as runnable in the following cases: 76.Bl -bullet -offset indent 77.It 78The target process is sleeping uninterruptibly. 79The signal will be 80noticed when the process returns from the system call or trap. 81.It 82The target process is currently ignoring the signal. 83.It 84If a stop signal is sent to a sleeping process that takes the 85default action 86(see 87.Xr sigaction 2 ) , 88the process is stopped without awakening it. 89.It 90.Dv SIGCONT 91restarts a stopped process 92(or puts them back to sleep) 93regardless of the signal action 94(e.g., blocked or ignored). 95.El 96.Pp 97If the target process is being traced 98.Fn psignal 99behaves as if the target process were taking the default action for 100.Fa signum . 101This allows the tracing process to be notified of the signal. 102.Pp 103The 104.Fn pgsignal 105function posts signal number 106.Fa signum 107to each member of the process group described by 108.Fa pgrp . 109If 110.Fa checkctty 111is non-zero, the signal will be posted only to processes that have 112a controlling terminal. 113.Fn pgsignal 114is implemented by walking along the process list headed by the field 115.Li pg_members 116of the process group structure 117pointed at by 118.Fa pgrp 119and calling 120.Fn psignal 121as appropriate. 122If 123.Fa pgrp 124is 125.Dv NULL 126no action is taken. 127.Pp 128The 129.Fn gsignal 130function posts signal number 131.Fa signum 132to each member of the process group identified by the group id 133.Fa pgid . 134.Fn gsignal 135first finds the group structure associated with 136.Fa pgid , 137then invokes 138.Fn pgsignal 139with the argument 140.Fa checkctty 141set to zero. 142If 143.Fa pgid 144is zero no action is taken. 145.Sh SEE ALSO 146.Xr sigaction 2 , 147.Xr signal 9 , 148.Xr tsleep 9 149