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 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 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 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