Import the new truncate(1) utility.
Approved by: jdp
This commit is contained in:
Sheldon Hearn
parent
f928d1a2f2
commit
edeb84a1b2
@ -158,6 +158,7 @@ SUBDIR= apply \
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tput \
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tr \
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true \
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truncate \
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truss \
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tset \
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tsort \
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5
usr.bin/truncate/Makefile
Normal file
5
usr.bin/truncate/Makefile
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@ -0,0 +1,5 @@
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# $FreeBSD$
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PROG= truncate
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.include <bsd.prog.mk>
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144
usr.bin/truncate/truncate.1
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144
usr.bin/truncate/truncate.1
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@ -0,0 +1,144 @@
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.\"
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.\" Copyright (c) 2000 Sheldon Hearn <sheldonh@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, 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 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 AUTHOR 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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.\" $FreeBSD$
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.\"
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.Dd Jul 4, 2000
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.Dt TRUNCATE 1
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.Os
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.Sh NAME
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.Nm truncate
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.Nd truncate or extend the length of files
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.Sh SYNOPSIS
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.Nm truncate
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.Op Fl c
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.Bk -words
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.Fl s Xo
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.Sm off
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.Op + | -
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.Ar size
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.Op K | M | G
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.Sm on
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.Xc
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.Ek
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.Ar
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.Nm truncate
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.Op Fl c
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.Bk -words
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.Fl r Ar rfile
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.Ek
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.Ar
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.Sh DESCRIPTION
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The
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.Nm
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utility adjusts the length of each regular file given on the command-line.
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.Pp
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The following options are available:
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.Bl -tag -width indent
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.It Fl c
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Do not create files if they do not exist.
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The
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.Nm
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utility does not treat this as an error.
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No error messages are displayed
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and the exit value is not affected.
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.It Fl r Ar rfile
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Truncate files to the length of the file
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.Ar rfile .
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.It Fl s Xo
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.Sm off
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.Op + | -
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.Ar size
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.Op K | M | G
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.Sm on
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.Xc
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If the
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.Ar size
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argument is preceded by a plus sign
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.Pq Sq + ,
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files will be extended by this number of bytes.
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If the
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.Ar size
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argument is preceded by a dash
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.Pq Sq - ,
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file lengths will be reduced by no more than this number of bytes,
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to a minimum length of zero bytes.
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Otherwise, the
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.Ar size
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argument specifies an absolute length to which all files
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should be extended or reduced as appropriate.
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.Pp
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The
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.Ar size
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argument may be suffixed with one of
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.Sq K ,
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.Sq M ,
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.Sq G
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to indicate a multiple of
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Kilobytes, Megabytes or Gigabytes
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respectively.
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.El
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.Pp
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Exactly one of the
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.Fl r
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and
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.Fl s
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options must be specified.
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.Pp
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If a file is made smaller, its extra data is lost.
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If a file is made larger,
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it will be extended as if by writing bytes with the value zero.
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If the file does not exist,
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it is created unless the
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.Fl c
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option is specified.
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.Pp
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Note that,
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while truncating a file causes space on disk to be freed,
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extending a file does not cause space to be allocated.
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To extend a file and actually allocate the space,
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it is necessary to explicitly write data to it,
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using (for example) the shell's
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.Ql >>
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redirection syntax, or
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.Xr dd 1 .
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.Sh DIAGNOSTICS
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The
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.Nm
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utility exits 0 on success,
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and >0 if an error occurs.
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If the operation fails for an argument,
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.Nm
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will issue a diagnostic
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and continue processing the remaining arguments.
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.Sh SEE ALSO
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.Xr dd 1 ,
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.Xr touch 1 ,
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.Xr truncate 2
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.Sh HISTORY
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The
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.Nm
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utility first appeared in
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.Fx 5.0 .
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202
usr.bin/truncate/truncate.c
Normal file
202
usr.bin/truncate/truncate.c
Normal file
@ -0,0 +1,202 @@
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/*
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* Copyright (c) 2000 FreeBSD, Inc. 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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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* $FreeBSD$
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*/
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <ctype.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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static off_t parselength __P((char *, off_t *));
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static void usage __P((void));
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static int no_create;
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static int do_relative;
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static int do_refer;
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static int got_size;
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int
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main(int argc, char **argv)
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{
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struct stat sb;
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mode_t omode;
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off_t oflow, rsize, sz, tsize;
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int ch, error, fd, oflags;
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char *fname, *rname;
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error = 0;
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while ((ch = getopt(argc, argv, "cr:s:")) != -1)
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switch (ch) {
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case 'c':
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no_create++;
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break;
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case 'r':
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do_refer++;
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rname = optarg;
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break;
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case 's':
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if (parselength(optarg, &sz) == -1)
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errx(EXIT_FAILURE,
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"invalid size argument `%s'", optarg);
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if (*optarg == '+' || *optarg == '-')
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do_relative++;
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got_size++;
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break;
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default:
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usage();
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/* NOTREACHED */
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}
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argv += optind;
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argc -= optind;
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/*
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* Exactly one of do_refer or got_size must be specified. Since
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* do_relative implies got_size, do_relative and do_refer are
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* also mutually exclusive. See usage() for allowed invocations.
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*/
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if (!(do_refer || got_size) || (do_refer && got_size) || argc < 1)
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usage();
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if (do_refer) {
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if (stat(rname, &sb) == -1)
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err(EXIT_FAILURE, "%s", rname);
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tsize = sb.st_size;
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} else if (got_size) {
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if (do_relative)
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rsize = sz;
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else
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tsize = sz;
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}
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if (no_create)
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oflags = O_WRONLY;
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else
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oflags = O_WRONLY | O_CREAT;
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omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
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while ((fname = *argv++) != NULL) {
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if ((fd = open(fname, oflags, omode)) == -1) {
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if (errno != ENOENT) {
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warn("%s", fname);
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error++;
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}
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continue;
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}
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if (do_relative) {
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if (fstat(fd, &sb) == -1) {
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warn("%s", fname);
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error++;
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continue;
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}
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oflow = sb.st_size + rsize;
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if (oflow < (sb.st_size + rsize)) {
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errno = EFBIG;
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warn("%s", fname);
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error++;
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continue;
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}
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tsize = oflow;
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}
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if (tsize < 0)
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tsize = 0;
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if (ftruncate(fd, tsize) == -1) {
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warn("%s", fname);
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error++;
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continue;
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}
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}
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return error ? EXIT_FAILURE : EXIT_SUCCESS;
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}
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/*
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* Return the numeric value of a string given in the form [+-][0-9]+[GMK]
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* or -1 on format error or overflow.
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*/
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static off_t
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parselength(char *ls, off_t *sz)
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{
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off_t length, oflow;
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int lsign;
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length = 0;
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lsign = 1;
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switch (*ls) {
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case '-':
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lsign = -1;
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case '+':
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ls++;
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}
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#define ASSIGN_CHK_OFLOW(x, y) if (x < y) return -1; y = x
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/*
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* Calculate the value of the decimal digit string, failing
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* on overflow.
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*/
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while (isdigit(*ls)) {
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oflow = length * 10 + *ls++ - '0';
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ASSIGN_CHK_OFLOW(oflow, length);
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}
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switch (*ls) {
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case 'G':
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oflow = length * 1024;
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ASSIGN_CHK_OFLOW(oflow, length);
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case 'M':
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oflow = length * 1024;
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ASSIGN_CHK_OFLOW(oflow, length);
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case 'K':
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if (ls[1] != '\0')
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return -1;
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oflow = length * 1024;
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ASSIGN_CHK_OFLOW(oflow, length);
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case '\0':
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break;
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default:
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return -1;
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}
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*sz = length * lsign;
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return 0;
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}
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static void
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usage(void)
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{
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fprintf(stderr, "%s\n%s\n",
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"usage: truncate [-c] -s [+|-]size[K|M|G] file ...",
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" truncate [-c] -r rfile file ...");
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exit(EXIT_FAILURE);
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}
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