1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2002 Tim J. Robbins.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29/*
30 * tabs -- set terminal tabs
31 *
32 * This utility displays a series of characters that clears the terminal
33 * hardware tab settings, then initialises them to specified values,
34 * and optionally sets a soft margin.
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD$");
39
40#include <sys/types.h>
41#include <sys/tty.h>
42
43#include <ctype.h>
44#include <err.h>
45#include <errno.h>
46#include <locale.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <string.h>
50#include <term.h>
51#include <unistd.h>
52
53/* Maximum number of tab stops allowed in table. */
54#define NSTOPS		20
55
56#define NELEMS(a) (sizeof(a) / sizeof(a[0]))
57
58/* Predefined formats, taken from IEEE Std 1003.1-2001. */
59static const struct {
60	const char	*name;		/* Format name used on cmd. line */
61	long		stops[NSTOPS];	/* Column positions */
62} formats[] = {
63	{ "a",	{ 1, 10, 16, 36, 72 } },
64	{ "a2",	{ 1, 10, 16, 40, 72 } },
65	{ "c",	{ 1, 8, 12, 16, 20, 55 } },
66	{ "c2",	{ 1, 6, 10, 14, 49 } },
67	{ "c3", { 1, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58,
68		62, 67 } },
69	{ "f",	{ 1, 7, 11, 15, 19, 23 } },
70	{ "p",	{ 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57,
71		61 } },
72	{ "s",	{ 1, 10, 55 } },
73	{ "u",	{ 1, 12, 20, 44 } }
74};
75
76static void	 gettabs(char *, long *, long *);
77static int	 ttywidth(void);
78static void	 usage(void);
79
80int
81main(int argc __unused, char *argv[])
82{
83	long cols, i, inc, j, margin, nstops, stops[NSTOPS];
84	const char *cr, *ct, *st, *ML;
85	char area[1024], *ap, *arg, *end;
86
87	setlocale(LC_ALL, "");
88
89	inc = 8;
90	margin = 0;
91	nstops = -1;
92	while ((arg = *++argv) != NULL && (*arg == '-' || *arg == '+')) {
93		if (*arg == '+') {
94			/* +m[n] or +[n] */
95			if (*++arg == 'm')
96				arg++;
97			if (*arg != '\0') {
98				errno = 0;
99				margin = strtol(arg, &end, 10);
100				if (errno != 0 || *end != '\0' || margin < 0)
101					errx(1, "%s: invalid margin width",
102					    arg);
103			} else
104				margin = 10;
105		} else if (isdigit(arg[1])) {
106			/* -n */
107			errno = 0;
108			inc = strtol(arg + 1, &end, 10);
109			if (errno != 0 || *end != '\0' || inc < 0)
110				errx(1, "%s: invalid increment", arg + 1);
111		} else if (arg[1] == 'T') {
112			/* -Ttype or -T type */
113			if (arg[2] != '\0')
114				setenv("TERM", arg + 2, 1);
115			else {
116				if ((arg = *++argv) == NULL)
117					usage();
118				setenv("TERM", arg, 1);
119			}
120		} else if (arg[1] == '-') {
121			arg = *++argv;
122			break;
123		} else {
124			/* Predefined format */
125			for (i = 0; i < (int)NELEMS(formats); i++)
126				if (strcmp(formats[i].name, arg + 1) == 0)
127					break;
128			if (i == NELEMS(formats))
129				usage();
130			for (j = nstops = 0; j < NSTOPS &&
131			    formats[i].stops[j] != 0; j++)
132				stops[nstops++] = formats[i].stops[j];
133		}
134	}
135
136	if (arg != NULL) {
137		if (nstops != -1)
138			usage();
139		gettabs(arg, stops, &nstops);
140	}
141
142	/* Initialise terminal, get the strings we need */
143	setupterm(NULL, 1, NULL);
144	ap = area;
145	if ((ct = tgetstr("ct", &ap)) == NULL)
146		errx(1, "terminal cannot clear tabs");
147	if ((st = tgetstr("st", &ap)) == NULL)
148		errx(1, "terminal cannot set tabs");
149	if ((cr = tgetstr("cr", &ap)) == NULL)
150		cr = "\r";
151	ML = tgetstr("ML", &ap);
152	cols = ttywidth();
153
154	/* Clear all tabs. */
155	putp(cr);
156	putp(ct);
157
158	/*
159	 * Set soft margin.
160	 * XXX Does this actually work?
161	 */
162	if (ML != NULL) {
163		printf("%*s", (int)margin, "");
164		putp(ML);
165	} else if (margin != 0)
166		warnx("terminal cannot set left margin");
167
168	/* Optionally output new tab stops. */
169	if (nstops >= 0) {
170		printf("%*s", (int)stops[0] - 1, "");
171		putp(st);
172		for (i = 1; i < nstops; i++) {
173			printf("%*s", (int)(stops[i] - stops[i - 1]), "");
174			putp(st);
175		}
176	} else if (inc > 0) {
177		for (i = 0; i < cols / inc; i++) {
178			putp(st);
179			printf("%*s", (int)inc, "");
180		}
181		putp(st);
182	}
183	putp(cr);
184
185	exit(0);
186}
187
188static void
189usage(void)
190{
191
192	fprintf(stderr,
193"usage: tabs [-n|-a|-a2|-c|-c2|-c3|-f|-p|-s|-u] [+m[n]] [-T type]\n");
194	fprintf(stderr,
195"       tabs [-T type] [+[n]] n1,[n2,...]\n");
196	exit(1);
197}
198
199static void
200gettabs(char *arg, long stops[], long *nstops)
201{
202	char *tok, *end;
203	long last, stop;
204
205	for (last = *nstops = 0, tok = strtok(arg, ","); tok != NULL;
206	    tok = strtok(NULL, ",")) {
207		if (*nstops >= NSTOPS)
208			errx(1, "too many tab stops (limit %d)", NSTOPS);
209		errno = 0;
210		stop = strtol(tok, &end, 10);
211		if (errno != 0 || *end != '\0' || stop <= 0)
212			errx(1, "%s: invalid tab stop", tok);
213		if (*tok == '+') {
214			if (tok == arg)
215				errx(1, "%s: first tab may not be relative",
216				    tok);
217			stop += last;
218		}
219		if (last > stop)
220			errx(1, "cannot go backwards");
221		last = stops[(*nstops)++] = stop;
222	}
223}
224
225static int
226ttywidth(void)
227{
228	struct winsize ws;
229	int width;
230
231	if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1)
232		width = ws.ws_col;
233	else if ((width = tgetnum("co")) == 0) {
234		width = 80;
235		warnx("cannot find terminal width; defaulted to %d", width);
236	}
237
238	return (width);
239}
240