1.\" $NetBSD: psignal.9,v 1.1 1996/06/22 22:57:35 pk Exp $ 2.\" 3.\" Copyright (c) 1996 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Paul Kranenburg. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 29.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd June 22, 1996 38.Dt PSIGNAL 9 39.Os 40.Sh NAME 41.Nm psignal , 42.Nm pgsignal , 43.Nm gsignal 44.Nd post signal to a process or process group 45.Sh SYNOPSIS 46.Ft void 47.Fn "psignal" "struct proc *p" "int signum" 48.Ft void 49.Fn "pgsignal" "struct pgrp *pgrp" "int signum" "int checkctty" 50.Ft void 51.Fn "gsignal" "int pgid" "int signum" 52.Sh DESCRIPTION 53These functions post a signal to one or more processes. The argument 54.Fa signum 55common to all three functions should be in the range 56.Bq 1- Ns Dv NSIG . 57.Pp 58The 59.Fn psignal 60function posts signal number 61.Fa signum 62to the process represented by the process structure 63.Fa p . 64With a few exceptions noted below, the target process signal disposition is 65updated and is marked as runnable, so further handling of the signal is done 66in the context of the target process after a context switch. Note that 67.Fn psignal 68does not by itself cause a context switch to happen. 69.Pp 70The target process is not marked as runnable in the following cases: 71.Bl -bullet -offset indent 72.It 73The target process is sleeping uninterruptibly. The signal will be 74noticed when the process returns from the system call or trap. 75.It 76The target process is currently ignoring the signal. 77.It 78If a stop signal is sent to a sleeping process that takes the 79default action 80.Pq see Xr sigaction 2 , 81the process is stopped without awakening it. 82.It 83.Dv SIGCONT 84restarts a stopped process 85.Pq or puts them back to sleep 86regardless of the signal action 87.Pq 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. If 115.Fa pgrp 116is 117.Dv NULL 118no action is taken. 119.Pp 120The 121.Fn gsignal 122function posts signal number 123.Fa signum 124to each member of the process group identified by the group id 125.Fa pgid . 126.Fn gsignal 127first finds the group structure associated with 128.Fa pgid , 129then invokes 130.Fn pgsignal 131with the argument 132.Fa checkctty 133set to zero. If 134.Fa pgid 135is zero no action is taken. 136.Sh SEE ALSO 137.Xr sigaction 2 , 138.Xr tsleep 9 139