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
122 lines
4 KiB
Groff
122 lines
4 KiB
Groff
.\" $NetBSD: adjtime.2,v 1.20 2004/05/13 10:20:57 wiz Exp $
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.\"
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.\" Copyright (c) 1980, 1991, 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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.\" @(#)adjtime.2 8.1 (Berkeley) 6/4/93
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.\"
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.Dd June 4, 1993
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.Dt ADJTIME 2
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.Os
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.Sh NAME
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.Nm adjtime
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.Nd "correct the time to allow synchronization of the system clock"
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/time.h
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.Ft int
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.Fn adjtime "const struct timeval *delta" "struct timeval *olddelta"
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.Sh DESCRIPTION
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.Fn adjtime
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makes small adjustments to the system time, as returned by
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.Xr gettimeofday 2 ,
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advancing or retarding it
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by the time specified by the timeval
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.Fa delta .
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If
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.Fa delta
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is negative, the clock is
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slowed down by incrementing it more slowly than normal until
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the correction is complete.
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If
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.Fa delta
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is positive, a larger increment than normal
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is used.
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The skew used to perform the correction is generally a fraction of one percent.
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Thus, the time is always
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a monotonically increasing function.
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A time correction from an earlier call to
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.Fn adjtime
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may not be finished when
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.Fn adjtime
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is called again.
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If
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.Fa olddelta
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is non-nil,
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the structure pointed to will contain, upon return, the
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number of microseconds still to be corrected
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from the earlier call.
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.Pp
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This call may be used by time servers that synchronize the clocks
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of computers in a local area network.
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Such time servers would slow down the clocks of some machines
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and speed up the clocks of others to bring them to the average network time.
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.Pp
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If the calling user is not the super user, then the
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.Fn adjtime
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function in the standard C library will try to use the
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.Xr clockctl 4
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device if present, thus making possible for non privileged users to
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adjust the system time.
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If
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.Xr clockctl 4
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is not present or not accessible, then
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.Fn adjtime
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reverts to the
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.Fn adjtime
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system call, which is restricted to the super user.
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.Sh RETURN VALUES
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A return value of 0 indicates that the call succeeded.
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A return value of \-1 indicates that an error occurred, and in this
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case an error code is stored in the global variable
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.Va errno .
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.Sh ERRORS
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.Fn adjtime
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will fail if:
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.Bl -tag -width Er
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.It Bq Er EFAULT
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An argument points outside the process's allocated address space.
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.It Bq Er EPERM
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The process's effective user ID is not that of the super user.
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.El
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.Sh SEE ALSO
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.Xr date 1 ,
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.Xr gettimeofday 2 ,
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.Xr clockctl 4 ,
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.Xr timed 8 ,
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.Xr timedc 8
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.Rs
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.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD"
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.%A R. Gusella
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.%A S. Zatti
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.Re
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.Sh HISTORY
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The
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.Fn adjtime
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function call appeared in
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.Bx 4.3 .
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