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
115 lines
3.5 KiB
Groff
115 lines
3.5 KiB
Groff
.\" $NetBSD: daemon.3,v 1.15 2003/08/07 16:42:46 agc Exp $
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.\"
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.\" Copyright (c) 1993
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.\" The Regents of the University of California. 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, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)daemon.3 8.1 (Berkeley) 6/9/93
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.\"
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.Dd September 3, 1999
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.Dt DAEMON 3
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.Os
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.Sh NAME
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.Nm daemon
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.Nd run in the background
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdlib.h
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.Ft int
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.Fn daemon "int nochdir" "int noclose"
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.Sh DESCRIPTION
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The
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.Fn daemon
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function is for programs wishing to detach themselves from the
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controlling terminal and run in the background as system daemons.
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.Pp
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Unless the argument
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.Fa nochdir
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is non-zero,
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.Fn daemon
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changes the current working directory to the root
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.Pq Pa / .
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.Pp
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Unless the argument
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.Fa noclose
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is non-zero,
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.Fn daemon
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will redirect standard input, standard output and standard error
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to
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.Pa /dev/null .
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.Sh RETURN VALUES
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On return 0 indicates success with \-1 indicating error.
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.Sh ERRORS
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The function
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.Fn daemon
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may fail and set
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.Va errno
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for any of the errors specified for the library functions
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.Xr fork 2
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and
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.Xr setsid 2 .
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.Sh SEE ALSO
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.Xr fork 2 ,
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.Xr setsid 2
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.Sh HISTORY
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The
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.Fn daemon
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function first appeared in
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.Bx 4.4 .
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.Sh CAVEATS
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Unless the
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.Ar noclose
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argument is non-zero,
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.Fn daemon
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will close the first three file descriptors and redirect them to
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.Pa /dev/null .
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Normally, these correspond to standard input, standard output and
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standard error.
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However, if any of those file descriptors refer to something else they
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will still be closed, resulting in incorrect behavior of the calling program.
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This can happen if any of standard input, standard output or standard error
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have been closed before the program was run.
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Programs using
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.Fn daemon
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should therefore make sure to either call
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.Fn daemon
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before opening any files or sockets or, alternately, verifying that
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any file descriptors obtained have a value greater than 2.
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.Sh BUGS
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.Fn daemon
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uses
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.Fn fork
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as part of its tty detachment mechanism.
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Consequently the process id changes when
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.Fn daemon
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is invoked.
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Processes employing
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.Fn daemon
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can not be reliably waited upon until
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.Fn daemon
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has been invoked.
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