1/*-
2 * Copyright (c) 2000 Sheldon Hearn <sheldonh@FreeBSD.org>.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 */
27
28#ifndef lint
29static const char rcsid[] =
30    "$FreeBSD$";
31#endif
32
33#include <sys/stat.h>
34
35#include <ctype.h>
36#include <err.h>
37#include <errno.h>
38#include <fcntl.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <unistd.h>
42
43#include <libutil.h>
44
45static void	usage(void);
46
47static int	no_create;
48static int	do_relative;
49static int	do_refer;
50static int	got_size;
51
52int
53main(int argc, char **argv)
54{
55	struct stat	sb;
56	mode_t	omode;
57	off_t	oflow, rsize, tsize;
58	int64_t sz;
59	int	ch, error, fd, oflags;
60	char   *fname, *rname;
61
62	fd = -1;
63	rsize = tsize = sz = 0;
64	error = 0;
65	rname = NULL;
66	while ((ch = getopt(argc, argv, "cr:s:")) != -1)
67		switch (ch) {
68		case 'c':
69			no_create = 1;
70			break;
71		case 'r':
72			do_refer = 1;
73			rname = optarg;
74			break;
75		case 's':
76			if (expand_number(optarg, &sz) == -1)
77				errx(EXIT_FAILURE,
78				    "invalid size argument `%s'", optarg);
79			if (*optarg == '+' || *optarg == '-')
80				do_relative = 1;
81			got_size = 1;
82			break;
83		default:
84			usage();
85			/* NOTREACHED */
86		}
87
88	argv += optind;
89	argc -= optind;
90
91	/*
92	 * Exactly one of do_refer or got_size must be specified.  Since
93	 * do_relative implies got_size, do_relative and do_refer are
94	 * also mutually exclusive.  See usage() for allowed invocations.
95	 */
96	if (do_refer + got_size != 1 || argc < 1)
97		usage();
98	if (do_refer) {
99		if (stat(rname, &sb) == -1)
100			err(EXIT_FAILURE, "%s", rname);
101		tsize = sb.st_size;
102	} else if (do_relative)
103		rsize = sz;
104	else
105		tsize = sz;
106
107	if (no_create)
108		oflags = O_WRONLY;
109	else
110		oflags = O_WRONLY | O_CREAT;
111	omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
112
113	while ((fname = *argv++) != NULL) {
114		if (fd != -1)
115			close(fd);
116		if ((fd = open(fname, oflags, omode)) == -1) {
117			if (errno != ENOENT) {
118				warn("%s", fname);
119				error++;
120			}
121			continue;
122		}
123		if (do_relative) {
124			if (fstat(fd, &sb) == -1) {
125				warn("%s", fname);
126				error++;
127				continue;
128			}
129			oflow = sb.st_size + rsize;
130			if (oflow < (sb.st_size + rsize)) {
131				errno = EFBIG;
132				warn("%s", fname);
133				error++;
134				continue;
135			}
136			tsize = oflow;
137		}
138		if (tsize < 0)
139			tsize = 0;
140
141		if (ftruncate(fd, tsize) == -1) {
142			warn("%s", fname);
143			error++;
144			continue;
145		}
146	}
147	if (fd != -1)
148		close(fd);
149
150	return error ? EXIT_FAILURE : EXIT_SUCCESS;
151}
152
153static void
154usage(void)
155{
156	fprintf(stderr, "%s\n%s\n",
157	    "usage: truncate [-c] -s [+|-]size[K|k|M|m|G|g|T|t] file ...",
158	    "       truncate [-c] -r rfile file ...");
159	exit(EXIT_FAILURE);
160}
161