GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.bin/tail/tail.c Lines: 32 92 34.8 %
Date: 2016-12-06 Branches: 26 102 25.5 %

Line Branch Exec Source
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/*	$OpenBSD: tail.c,v 1.21 2016/02/03 12:23:57 halex Exp $	*/
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/*-
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 * Copyright (c) 1991, 1993
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 *	The Regents of the University of California.  All rights reserved.
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 *
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 * This code is derived from software contributed to Berkeley by
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 * Edward Sze-Tyan Wang.
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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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#include <sys/types.h>
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#include <sys/stat.h>
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#include <err.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "extern.h"
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int fflag, rflag, rval;
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int is_stdin;
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static void obsolete(char **);
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static void usage(void);
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int
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main(int argc, char *argv[])
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{
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	struct tailfile *tf;
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	off_t off = 0;
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	enum STYLE style;
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	int ch;
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	int i;
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	char *p;
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	if (pledge("stdio rpath wpath cpath", NULL) == -1)
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		err(1, "pledge");
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	/*
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	 * Tail's options are weird.  First, -n10 is the same as -n-10, not
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	 * -n+10.  Second, the number options are 1 based and not offsets,
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	 * so -n+1 is the first line, and -c-1 is the last byte.  Third, the
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	 * number options for the -r option specify the number of things that
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	 * get displayed, not the starting point in the file.  The one major
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	 * incompatibility in this version as compared to historical versions
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	 * is that the 'r' option couldn't be modified by the -lbc options,
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	 * i.e. it was always done in lines.  This version treats -rc as a
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	 * number of characters in reverse order.  Finally, the default for
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	 * -r is the entire file, not 10 lines.
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	 */
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#define	ARG(units, forward, backward) {					\
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	if (style)							\
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		usage();						\
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	off = strtoll(optarg, &p, 10) * (units);			\
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	if (*p)								\
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		errx(1, "illegal offset -- %s", optarg);		\
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	switch(optarg[0]) {						\
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	case '+':							\
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		if (off)						\
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			off -= (units);					\
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			style = (forward);				\
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		break;							\
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	case '-':							\
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		off = -off;						\
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		/* FALLTHROUGH */					\
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	default:							\
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		style = (backward);					\
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		break;							\
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	}								\
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}
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	obsolete(argv);
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	style = NOTSET;
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	while ((ch = getopt(argc, argv, "b:c:fn:r")) != -1)
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		switch(ch) {
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		case 'b':
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			ARG(512, FBYTES, RBYTES);
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			break;
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		case 'c':
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			ARG(1, FBYTES, RBYTES);
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			break;
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		case 'f':
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			fflag = 1;
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			break;
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		case 'n':
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			ARG(1, FLINES, RLINES);
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			break;
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		case 'r':
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			rflag = 1;
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			break;
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		case '?':
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		default:
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			usage();
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		}
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	argc -= optind;
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	argv += optind;
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	/*
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	 * If displaying in reverse, don't permit follow option, and convert
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	 * style values.
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	 */
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	if (rflag) {
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		if (fflag)
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			usage();
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		if (style == FBYTES)
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			style = RBYTES;
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		else if (style == FLINES)
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			style = RLINES;
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	}
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	/*
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	 * If style not specified, the default is the whole file for -r, and
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	 * the last 10 lines if not -r.
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	 */
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	if (style == NOTSET) {
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		if (rflag) {
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			off = 0;
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			style = REVERSE;
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		} else {
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			off = 10;
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			style = RLINES;
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		}
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	}
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	if ((tf = reallocarray(NULL, argc ? argc : 1, sizeof(*tf))) == NULL)
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		err(1, "reallocarray");
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	if (argc) {
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		for (i = 0; *argv; i++) {
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			tf[i].fname = *argv++;
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			if ((tf[i].fp = fopen(tf[i].fname, "r")) == NULL ||
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			    fstat(fileno(tf[i].fp), &(tf[i].sb))) {
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				ierr(tf[i].fname);
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				i--;
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				continue;
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			}
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		}
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		if (rflag)
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			reverse(tf, i, style, off);
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		else
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			forward(tf, i, style, off);
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	}
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	else {
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		if (pledge("stdio wpath cpath rpath", NULL) == -1)
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			err(1, "pledge");
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		tf[0].fname = "stdin";
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		tf[0].fp = stdin;
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		is_stdin = 1;
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		if (fstat(fileno(stdin), &(tf[0].sb))) {
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			ierr(tf[0].fname);
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			exit(1);
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		}
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		/*
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		 * Determine if input is a pipe.  4.4BSD will set the SOCKET
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		 * bit in the st_mode field for pipes.  Fix this then.
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		 */
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		if (lseek(fileno(tf[0].fp), (off_t)0, SEEK_CUR) == -1 &&
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		    errno == ESPIPE) {
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			errno = 0;
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			fflag = 0;		/* POSIX.2 requires this. */
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		}
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		if (rflag)
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			reverse(tf, 1, style, off);
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		else
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			forward(tf, 1, style, off);
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	}
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	exit(rval);
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}
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/*
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 * Convert the obsolete argument form into something that getopt can handle.
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 * This means that anything of the form [+-][0-9][0-9]*[lbc][fr] that isn't
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 * the option argument for a -b, -c or -n option gets converted.
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 */
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static void
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obsolete(char *argv[])
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{
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	char *ap, *p, *t;
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	size_t len;
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	char *start;
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	while ((ap = *++argv)) {
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		/* Return if "--" or not an option of any form. */
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		if (ap[0] != '-') {
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			if (ap[0] != '+')
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				return;
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		} else if (ap[1] == '-')
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			return;
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		switch(*++ap) {
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		/* Old-style option. */
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		case '0': case '1': case '2': case '3': case '4':
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		case '5': case '6': case '7': case '8': case '9':
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			/* Malloc space for dash, new option and argument. */
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			len = strlen(*argv);
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			if ((start = p = malloc(len + 4)) == NULL)
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				err(1, NULL);
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			*p++ = '-';
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			/*
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			 * Go to the end of the option argument.  Save off any
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			 * trailing options (-3lf) and translate any trailing
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			 * output style characters.
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			 */
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			t = *argv + len - 1;
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			if (*t == 'f' || *t == 'r') {
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				*p++ = *t;
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				*t-- = '\0';
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			}
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			switch(*t) {
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			case 'b':
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				*p++ = 'b';
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				*t = '\0';
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				break;
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			case 'c':
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				*p++ = 'c';
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				*t = '\0';
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				break;
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			case 'l':
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				*t = '\0';
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				/* FALLTHROUGH */
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			case '0': case '1': case '2': case '3': case '4':
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			case '5': case '6': case '7': case '8': case '9':
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				*p++ = 'n';
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				break;
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			default:
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				errx(1, "illegal option -- %s", *argv);
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			}
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			*p++ = *argv[0];
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			(void)strlcpy(p, ap, start + len + 4 - p);
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			*argv = start;
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			continue;
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		/*
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		 * Options w/ arguments, skip the argument and continue
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		 * with the next option.
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		 */
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		case 'b':
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		case 'c':
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		case 'n':
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			if (!ap[1])
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				++argv;
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			/* FALLTHROUGH */
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		/* Options w/o arguments, continue with the next option. */
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		case 'f':
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		case 'r':
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			continue;
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		/* Illegal option, return and let getopt handle it. */
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		default:
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			return;
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		}
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	}
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}
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static void
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usage(void)
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{
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	(void)fprintf(stderr,
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	    "usage: tail [-f | -r] "
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	    "[-b number | -c number | -n number | -number] [file ...]\n");
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	exit(1);
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}