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.Fd #include <sys/types.h> 48.Fd #include <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. The argument 57.Fa signum 58common to all three functions should be in the range 59.Bq 1- Ns Dv NSIG . 60.Pp 61The 62.Fn psignal 63function posts signal number 64.Fa signum 65to the process represented by the process structure 66.Fa p . 67With a few exceptions noted below, the target process signal disposition is 68updated and is marked as runnable, so further handling of the signal is done 69in the context of the target process after a context switch. Note that 70.Fn psignal 71does not by itself cause a context switch to happen. 72.Pp 73The target process is not marked as runnable in the following cases: 74.Bl -bullet -offset indent 75.It 76The target process is sleeping uninterruptibly. The signal will be 77noticed when the process returns from the system call or trap. 78.It 79The target process is currently ignoring the signal. 80.It 81If a stop signal is sent to a sleeping process that takes the 82default action 83.Pq see Xr sigaction 2 , 84the process is stopped without awakening it. 85.It 86.Dv SIGCONT 87restarts a stopped process 88.Pq or puts them back to sleep 89regardless of the signal action 90.Pq e.g., blocked or ignored . 91.El 92.Pp 93If the target process is being traced 94.Fn psignal 95behaves as if the target process were taking the default action for 96.Fa signum . 97This allows the tracing process to be notified of the signal. 98.Pp 99The 100.Fn pgsignal 101function posts signal number 102.Fa signum 103to each member of the process group described by 104.Fa pgrp . 105If 106.Fa checkctty 107is non-zero, the signal will be posted only to processes that have 108a controlling terminal. 109.Fn pgsignal 110is implemented by walking along the process list headed by the field 111.Li pg_members 112of the process group structure 113pointed at by 114.Fa pgrp 115and calling 116.Fn psignal 117as appropriate. If 118.Fa pgrp 119is 120.Dv NULL 121no action is taken. 122.Pp 123The 124.Fn gsignal 125function posts signal number 126.Fa signum 127to each member of the process group identified by the group id 128.Fa pgid . 129.Fn gsignal 130first finds the group structure associated with 131.Fa pgid , 132then invokes 133.Fn pgsignal 134with the argument 135.Fa checkctty 136set to zero. If 137.Fa pgid 138is zero no action is taken. 139.Sh SEE ALSO 140.Xr sigaction 2 , 141.Xr tsleep 9 142