52183d0145
The uuidgen command, by means of the uuidgen syscall, generates one
or more Universally Unique Identifiers compatible with OSF/DCE 1.1
version 1 UUIDs.
From the Perforce logs (change 11995):
Round of cleanups:
o Give uuidgen() the correct prototype in syscalls.master
o Define struct uuid according to DCE 1.1 in sys/uuid.h
o Use struct uuid instead of uuid_t. The latter is defined
in sys/uuid.h but should not be used in kernel land.
o Add snprintf_uuid(), printf_uuid() and sbuf_printf_uuid()
to kern_uuid.c for use in the kernel (currently geom_gpt.c).
o Rename the non-standard struct uuid in kern/kern_uuid.c
to struct uuid_private and give it a slightly better definition
for better byte-order handling. See below.
o In sys/gpt.h, fix the broken uuid definitions to match the now
compliant struct uuid definition. See below.
o In usr.bin/uuidgen/uuidgen.c catch up with struct uuid change.
A note about byte-order:
The standard failed to provide a non-conflicting and
unambiguous definition for the binary representation. My initial
implementation always wrote the timestamp as a 64-bit little-endian
(2s-complement) integral. The clock sequence was always written
as a 16-bit big-endian (2s-complement) integral. After a good
nights sleep and couple of Pan Galactic Gargle Blasters (not
necessarily in that order :-) I reread the spec and came to the
conclusion that the time fields are always written in the native
by order, provided the the low, mid and hi chopping still occurs.
The spec mentions that you "might need to swap bytes if you talk
to a machine that has a different byte-order". The clock sequence
is always written in big-endian order (as is the IEEE 802 address)
because its division is resulting in bytes, making the ordering
unambiguous.
84 lines
2.6 KiB
Groff
84 lines
2.6 KiB
Groff
.\" Copyright (c) 2002 Marcel Moolenaar
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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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.\"
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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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd May 26, 2002
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.Dt UUIDGEN 2
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.Os
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.Sh NAME
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.Nm uuidgen
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.Nd generate universally unique identifiers
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/uuid.h
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.Ft int
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.Fn uuidgen "uuid_t *store" "int count"
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.Sh DESCRIPTION
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The
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.Nm
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system call generates
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.Fa count
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universally unique identifiers (UUIDs) and writes them to the buffer
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pointed to by
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.Fa store .
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The identifiers are generated according to the syntax and semantics of the
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DCE version 1 variant of universally unique identifiers. When no IEEE 802
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address is available for the node field a random multicast address is
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generated for each call.
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.Pp
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When multiple identifiers are requested, the
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.Nm
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system call will generate identifiers that are adjacent in time.
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.Pp
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Universally unique identifiers, also known as globally unique identifiers,
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are normally represented as:
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.Bd -literal -offset indent
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63d81915-7140-11d6-903d-00022d09712b
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.Ed
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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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.Nm
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system call can fail with:
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.Bl -tag -width Er
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.It Bq Er EFAULT
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The buffer pointed to by
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.Fa store
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could not be written to for any or all identifiers.
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.It Bq Er EINVAL
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The
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.Fa count
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parameter is less than 1 or larger than the hard upper limit of 2048.
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.El
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.Sh SEE ALSO
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.Xr uuidgen 1
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.Sh HISTORY
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The
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.Nm
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system call first appeared in
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.Fx 5.0 .
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