source: trunk/minix/commands/simple/truncate.c@ 10

Last change on this file since 10 was 9, checked in by Mattia Monga, 13 years ago

Minix 3.1.2a

File size: 4.6 KB
Line 
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#include <sys/stat.h>
29
30#include <ctype.h>
31#include <errno.h>
32#include <fcntl.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <unistd.h>
36
37static off_t parselength(char *, off_t *);
38static void usage(void);
39
40static int no_create;
41static int do_relative;
42static int do_refer;
43static int got_size;
44
45int
46main(int argc, char **argv)
47{
48 struct stat sb;
49 mode_t omode;
50 off_t oflow, rsize, sz, tsize;
51 int ch, error, fd, oflags;
52 char *fname, *rname;
53
54 rsize = tsize = 0;
55 error = 0;
56 rname = NULL;
57 while ((ch = getopt(argc, argv, "cr:s:")) != -1)
58 switch (ch) {
59 case 'c':
60 no_create = 1;
61 break;
62 case 'r':
63 do_refer = 1;
64 rname = optarg;
65 break;
66 case 's':
67 if (parselength(optarg, &sz) == -1) {
68 fprintf(stderr,
69 "invalid size argument `%s'", optarg);
70 exit(EXIT_FAILURE);
71 }
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 fprintf(stderr, "%s", rname);
94 exit(EXIT_FAILURE);
95 }
96 tsize = sb.st_size;
97 } else if (do_relative)
98 rsize = sz;
99 else
100 tsize = sz;
101
102 if (no_create)
103 oflags = O_WRONLY;
104 else
105 oflags = O_WRONLY | O_CREAT;
106 omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
107
108 while ((fname = *argv++) != NULL) {
109 if ((fd = open(fname, oflags, omode)) == -1) {
110 if (errno != ENOENT) {
111 perror(fname);
112 error++;
113 }
114 continue;
115 }
116 if (do_relative) {
117 if (fstat(fd, &sb) == -1) {
118 perror(fname);
119 error++;
120 continue;
121 }
122 oflow = sb.st_size + rsize;
123 if (oflow < (sb.st_size + rsize)) {
124 errno = EFBIG;
125 perror(fname);
126 error++;
127 continue;
128 }
129 tsize = oflow;
130 }
131 if (tsize < 0)
132 tsize = 0;
133
134 if (ftruncate(fd, tsize) == -1) {
135 perror(fname);
136 error++;
137 continue;
138 }
139
140 close(fd);
141 }
142
143 return error ? EXIT_FAILURE : EXIT_SUCCESS;
144}
145
146/*
147 * Return the numeric value of a string given in the form [+-][0-9]+[GMK]
148 * or -1 on format error or overflow.
149 */
150static off_t
151parselength(char *ls, off_t *sz)
152{
153 off_t length, oflow;
154 int lsign;
155
156 length = 0;
157 lsign = 1;
158
159 switch (*ls) {
160 case '-':
161 lsign = -1;
162 case '+':
163 ls++;
164 }
165
166#define ASSIGN_CHK_OFLOW(x, y) if (x < y) return -1; y = x
167 /*
168 * Calculate the value of the decimal digit string, failing
169 * on overflow.
170 */
171 while (isdigit(*ls)) {
172 oflow = length * 10 + *ls++ - '0';
173 ASSIGN_CHK_OFLOW(oflow, length);
174 }
175
176 switch (*ls) {
177 case 'G':
178 case 'g':
179 oflow = length * 1024;
180 ASSIGN_CHK_OFLOW(oflow, length);
181 case 'M':
182 case 'm':
183 oflow = length * 1024;
184 ASSIGN_CHK_OFLOW(oflow, length);
185 case 'K':
186 case 'k':
187 if (ls[1] != '\0')
188 return -1;
189 oflow = length * 1024;
190 ASSIGN_CHK_OFLOW(oflow, length);
191 case '\0':
192 break;
193 default:
194 return -1;
195 }
196
197 *sz = length * lsign;
198 return 0;
199}
200
201static void
202usage(void)
203{
204 fprintf(stderr, "%s\n%s\n",
205 "usage: truncate [-c] -s [+|-]size[K|k|M|m|G|g] file ...",
206 " truncate [-c] -r rfile file ...");
207 exit(EXIT_FAILURE);
208}
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