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 29 static 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 static int parselength(char *, off_t *); 44 static void usage(void); 45 46 static int no_create; 47 static int do_relative; 48 static int do_refer; 49 static int got_size; 50 51 int 52 main(int argc, char **argv) 53 { 54 struct stat sb; 55 mode_t omode; 56 off_t oflow, rsize, sz, tsize; 57 int ch, error, fd, oflags; 58 char *fname, *rname; 59 60 rsize = tsize = 0; 61 error = 0; 62 rname = NULL; 63 while ((ch = getopt(argc, argv, "cr:s:")) != -1) 64 switch (ch) { 65 case 'c': 66 no_create = 1; 67 break; 68 case 'r': 69 do_refer = 1; 70 rname = optarg; 71 break; 72 case 's': 73 if (parselength(optarg, &sz) == -1) 74 errx(EXIT_FAILURE, 75 "invalid size argument `%s'", optarg); 76 if (*optarg == '+' || *optarg == '-') 77 do_relative = 1; 78 got_size = 1; 79 break; 80 default: 81 usage(); 82 /* NOTREACHED */ 83 } 84 85 argv += optind; 86 argc -= optind; 87 88 /* 89 * Exactly one of do_refer or got_size must be specified. Since 90 * do_relative implies got_size, do_relative and do_refer are 91 * also mutually exclusive. See usage() for allowed invocations. 92 */ 93 if (do_refer + got_size != 1 || argc < 1) 94 usage(); 95 if (do_refer) { 96 if (stat(rname, &sb) == -1) 97 err(EXIT_FAILURE, "%s", rname); 98 tsize = sb.st_size; 99 } else if (do_relative) 100 rsize = sz; 101 else 102 tsize = sz; 103 104 if (no_create) 105 oflags = O_WRONLY; 106 else 107 oflags = O_WRONLY | O_CREAT; 108 omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH; 109 110 while ((fname = *argv++) != NULL) { 111 if (fd != -1) 112 close(fd); 113 if ((fd = open(fname, oflags, omode)) == -1) { 114 if (errno != ENOENT) { 115 warn("%s", fname); 116 error++; 117 } 118 continue; 119 } 120 if (do_relative) { 121 if (fstat(fd, &sb) == -1) { 122 warn("%s", fname); 123 error++; 124 continue; 125 } 126 oflow = sb.st_size + rsize; 127 if (oflow < (sb.st_size + rsize)) { 128 errno = EFBIG; 129 warn("%s", fname); 130 error++; 131 continue; 132 } 133 tsize = oflow; 134 } 135 if (tsize < 0) 136 tsize = 0; 137 138 if (ftruncate(fd, tsize) == -1) { 139 warn("%s", fname); 140 error++; 141 continue; 142 } 143 } 144 if (fd != -1) 145 close(fd); 146 147 return error ? EXIT_FAILURE : EXIT_SUCCESS; 148 } 149 150 /* 151 * Return the numeric value of a string given in the form [+-][0-9]+[GMKT] 152 * or -1 on format error or overflow. 153 */ 154 static int 155 parselength(char *ls, off_t *sz) 156 { 157 off_t length, oflow; 158 int lsign; 159 160 length = 0; 161 lsign = 1; 162 163 switch (*ls) { 164 case '-': 165 lsign = -1; 166 case '+': 167 ls++; 168 } 169 170 #define ASSIGN_CHK_OFLOW(x, y) if (x < y) return -1; y = x 171 /* 172 * Calculate the value of the decimal digit string, failing 173 * on overflow. 174 */ 175 while (isdigit(*ls)) { 176 oflow = length * 10 + *ls++ - '0'; 177 ASSIGN_CHK_OFLOW(oflow, length); 178 } 179 180 switch (*ls) { 181 case 'T': 182 case 't': 183 oflow = length * 1024; 184 ASSIGN_CHK_OFLOW(oflow, length); 185 case 'G': 186 case 'g': 187 oflow = length * 1024; 188 ASSIGN_CHK_OFLOW(oflow, length); 189 case 'M': 190 case 'm': 191 oflow = length * 1024; 192 ASSIGN_CHK_OFLOW(oflow, length); 193 case 'K': 194 case 'k': 195 if (ls[1] != '\0') 196 return -1; 197 oflow = length * 1024; 198 ASSIGN_CHK_OFLOW(oflow, length); 199 case '\0': 200 break; 201 default: 202 return -1; 203 } 204 205 *sz = length * lsign; 206 return 0; 207 } 208 209 static void 210 usage(void) 211 { 212 fprintf(stderr, "%s\n%s\n", 213 "usage: truncate [-c] -s [+|-]size[K|k|M|m|G|g|T|t] file ...", 214 " truncate [-c] -r rfile file ..."); 215 exit(EXIT_FAILURE); 216 } 217