2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
157 lines
4.3 KiB
Groff
157 lines
4.3 KiB
Groff
.\" $NetBSD: sigqueue.2,v 1.2 2011/01/10 06:26:30 wiz Exp $
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.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
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.\" All rights reserved.
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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(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in
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.\" the documentation and/or other materials provided with the
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.\" distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) 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
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.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD: src/lib/libc/sys/sigqueue.2,v 1.8 2006/09/17 21:27:34 ru Exp $
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.\"
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.Dd January 9, 2011
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.Dt SIGQUEUE 2
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.Os
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.Sh NAME
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.Nm sigqueue
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.Nd queue a signal to a process (REALTIME)
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In signal.h
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.Ft int
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.Fn sigqueue "pid_t pid" "int signo" "const union sigval value"
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.Ft int
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.Fn sigqueueinfo "pid_t pid" "const siginfo_t *info"
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.Sh DESCRIPTION
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The
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.Fn sigqueue
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system call causes the signal specified by
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.Fa signo
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to be sent with the value specified by
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.Fa value
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to the process specified by
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.Fa pid .
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If
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.Fa signo
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is zero (the null signal), error checking is performed but
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no signal is actually sent.
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The null signal can be used to check the
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validity of PID.
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.Pp
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The conditions required for a process to have permission to queue a
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signal to another process are the same as for the
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.Xr kill 2
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system call.
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The
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.Fn sigqueue
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system call queues a signal to a single process specified by the
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.Fa pid
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argument.
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.Pp
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The
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.Fn sigqueue
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system call is implemented using
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.Fn sigqueueinfo
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and passing the appropriate information in the
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.Fa info
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argument.
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.Pp
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The
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.Fn sigqueue
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system call returns immediately.
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If the resources were
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available to queue the signal, the signal will be queued and sent to
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the receiving process.
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.Pp
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If the value of
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.Fa pid
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causes
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.Fa signo
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to be generated for the sending process, and if
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.Fa signo
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is not blocked for the calling thread and if no other thread has
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.Fa signo
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unblocked or is waiting in a
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.Fn sigwait
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system call for
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.Fa signo ,
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either
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.Fa signo
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or at least the pending, unblocked signal will be delivered to the
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calling thread before
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.Fn sigqueue
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returns.
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Should any multiple pending signals in the range
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.Dv SIGRTMIN
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to
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.Dv SIGRTMAX
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be selected for delivery, it is the lowest numbered
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one.
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The selection order between realtime and non-realtime signals, or
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between multiple pending non-realtime signals, is unspecified.
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.Sh RETURN VALUES
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.Rv -std
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.Sh ERRORS
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The
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.Fn sigqueue
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system call
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will fail if:
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.Bl -tag -width Er
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.It Bq Er EAGAIN
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No resources are available to queue the signal.
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The process has already queued
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.Brq Dv SIGQUEUE_MAX
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signals that are still pending at the receiver(s),
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or a system-wide resource limit has been exceeded.
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.It Bq Er EEPERM
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The process does not have the appropriate privilege to send the signal
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to the receiving process.
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.It Bq Er EINVAL
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The value of the
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.Fa signo
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argument is an invalid or unsupported signal number.
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.It Bq Er ESRCH
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The process
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.Fa pid
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does not exist.
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.El
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.Sh SEE ALSO
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.Xr sigaction 2 ,
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.Xr siginfo 2 ,
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.Xr sigpending 2 ,
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.Xr sigsuspend 2 ,
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.Xr sigtimedwait 2 ,
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.Xr sigwait 2 ,
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.Xr sigwaitinfo 2 ,
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.Xr pause 3 ,
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.Xr pthread_sigmask 3
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.Sh STANDARDS
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The
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.Fn sigqueue
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system call conforms to
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.St -p1003.1-2004 .
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.Sh HISTORY
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Support for
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.Tn POSIX
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realtime signal queue first appeared in
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.Nx 6.0 .
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