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 * $FreeBSD: src/usr.bin/truncate/truncate.c,v 1.6.2.1 2000/08/04 08:05:52 sheldonh Exp $
27 */
28
29 #include <sys/stat.h>
30
31 #include <ctype.h>
32 #include <err.h>
33 #include <errno.h>
34 #include <fcntl.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <unistd.h>
38
39 static off_t parselength(char *, off_t *);
40 static void usage(void);
41
42 static int no_create;
43 static int do_relative;
44 static int do_refer;
45 static int got_size;
46
47 int
main(int argc,char ** argv)48 main(int argc, char **argv)
49 {
50 struct stat sb;
51 mode_t omode;
52 off_t oflow, rsize, sz, tsize;
53 int ch, error, fd, oflags;
54 char *fname, *rname;
55
56 rsize = tsize = sz = 0;
57 error = 0;
58 rname = NULL;
59 while ((ch = getopt(argc, argv, "cr:s:")) != -1)
60 switch (ch) {
61 case 'c':
62 no_create = 1;
63 break;
64 case 'r':
65 do_refer = 1;
66 rname = optarg;
67 break;
68 case 's':
69 if (parselength(optarg, &sz) == -1)
70 errx(EXIT_FAILURE,
71 "invalid size argument `%s'", optarg);
72 if (*optarg == '+' || *optarg == '-')
73 do_relative = 1;
74 got_size = 1;
75 break;
76 default:
77 usage();
78 /* NOTREACHED */
79 }
80
81 argv += optind;
82 argc -= optind;
83
84 /*
85 * Exactly one of do_refer or got_size must be specified. Since
86 * do_relative implies got_size, do_relative and do_refer are
87 * also mutually exclusive. See usage() for allowed invocations.
88 */
89 if (do_refer + got_size != 1 || argc < 1)
90 usage();
91 if (do_refer) {
92 if (stat(rname, &sb) == -1)
93 err(EXIT_FAILURE, "%s", rname);
94 tsize = sb.st_size;
95 } else if (do_relative)
96 rsize = sz;
97 else
98 tsize = sz;
99
100 if (no_create)
101 oflags = O_WRONLY;
102 else
103 oflags = O_WRONLY | O_CREAT;
104 omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
105
106 while ((fname = *argv++) != NULL) {
107 if ((fd = open(fname, oflags, omode)) == -1) {
108 if (errno != ENOENT) {
109 warn("%s", fname);
110 error++;
111 }
112 continue;
113 }
114 if (do_relative) {
115 if (fstat(fd, &sb) == -1) {
116 warn("%s", fname);
117 error++;
118 continue;
119 }
120 oflow = sb.st_size + rsize;
121 if (oflow < (sb.st_size + rsize)) {
122 errno = EFBIG;
123 warn("%s", fname);
124 error++;
125 continue;
126 }
127 tsize = oflow;
128 }
129 if (tsize < 0)
130 tsize = 0;
131
132 if (ftruncate(fd, tsize) == -1) {
133 warn("%s", fname);
134 error++;
135 continue;
136 }
137
138 close(fd);
139 }
140
141 return error ? EXIT_FAILURE : EXIT_SUCCESS;
142 }
143
144 /*
145 * Return the numeric value of a string given in the form [+-][0-9]+[GMK]
146 * or -1 on format error or overflow.
147 */
148 static off_t
parselength(char * ls,off_t * sz)149 parselength(char *ls, off_t *sz)
150 {
151 off_t length, oflow;
152 int lsign;
153
154 length = 0;
155 lsign = 1;
156
157 switch (*ls) {
158 case '-':
159 lsign = -1;
160 /* FALLTHROUGH */
161 case '+':
162 ls++;
163 }
164
165 #define ASSIGN_CHK_OFLOW(x, y) if (x < y) return -1; y = x
166 /*
167 * Calculate the value of the decimal digit string, failing
168 * on overflow.
169 */
170 while (isdigit(*ls)) {
171 oflow = length * 10 + *ls++ - '0';
172 ASSIGN_CHK_OFLOW(oflow, length);
173 }
174
175 switch (*ls) {
176 case 'T':
177 oflow = length * 1024;
178 ASSIGN_CHK_OFLOW(oflow, length);
179 /* FALLTHROUGH */
180 case 'G':
181 oflow = length * 1024;
182 ASSIGN_CHK_OFLOW(oflow, length);
183 /* FALLTHROUGH */
184 case 'M':
185 oflow = length * 1024;
186 ASSIGN_CHK_OFLOW(oflow, length);
187 /* FALLTHROUGH */
188 case 'K':
189 if (ls[1] != '\0')
190 return -1;
191 oflow = length * 1024;
192 ASSIGN_CHK_OFLOW(oflow, length);
193 case '\0':
194 break;
195 default:
196 return -1;
197 }
198
199 *sz = length * lsign;
200 return 0;
201 }
202
203 static void
usage(void)204 usage(void)
205 {
206 fprintf(stderr, "%s\n%s\n",
207 "usage: truncate [-c] -s [+|-]size[K|M|G|T] file ...",
208 " truncate [-c] -r rfile file ...");
209 exit(EXIT_FAILURE);
210 }
211