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 fd = -1; 61 rsize = tsize = sz = 0; 62 error = 0; 63 rname = NULL; 64 while ((ch = getopt(argc, argv, "cr:s:")) != -1) 65 switch (ch) { 66 case 'c': 67 no_create = 1; 68 break; 69 case 'r': 70 do_refer = 1; 71 rname = optarg; 72 break; 73 case 's': 74 if (parselength(optarg, &sz) == -1) 75 errx(EXIT_FAILURE, 76 "invalid size argument `%s'", optarg); 77 if (*optarg == '+' || *optarg == '-') 78 do_relative = 1; 79 got_size = 1; 80 break; 81 default: 82 usage(); 83 /* NOTREACHED */ 84 } 85 86 argv += optind; 87 argc -= optind; 88 89 /* 90 * Exactly one of do_refer or got_size must be specified. Since 91 * do_relative implies got_size, do_relative and do_refer are 92 * also mutually exclusive. See usage() for allowed invocations. 93 */ 94 if (do_refer + got_size != 1 || argc < 1) 95 usage(); 96 if (do_refer) { 97 if (stat(rname, &sb) == -1) 98 err(EXIT_FAILURE, "%s", rname); 99 tsize = sb.st_size; 100 } else if (do_relative) 101 rsize = sz; 102 else 103 tsize = sz; 104 105 if (no_create) 106 oflags = O_WRONLY; 107 else 108 oflags = O_WRONLY | O_CREAT; 109 omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH; 110 111 while ((fname = *argv++) != NULL) { 112 if (fd != -1) 113 close(fd); 114 if ((fd = open(fname, oflags, omode)) == -1) { 115 if (errno != ENOENT) { 116 warn("%s", fname); 117 error++; 118 } 119 continue; 120 } 121 if (do_relative) { 122 if (fstat(fd, &sb) == -1) { 123 warn("%s", fname); 124 error++; 125 continue; 126 } 127 oflow = sb.st_size + rsize; 128 if (oflow < (sb.st_size + rsize)) { 129 errno = EFBIG; 130 warn("%s", fname); 131 error++; 132 continue; 133 } 134 tsize = oflow; 135 } 136 if (tsize < 0) 137 tsize = 0; 138 139 if (ftruncate(fd, tsize) == -1) { 140 warn("%s", fname); 141 error++; 142 continue; 143 } 144 } 145 if (fd != -1) 146 close(fd); 147 148 return error ? EXIT_FAILURE : EXIT_SUCCESS; 149 } 150 151 /* 152 * Return the numeric value of a string given in the form [+-][0-9]+[GMKT] 153 * or -1 on format error or overflow. 154 */ 155 static int 156 parselength(char *ls, off_t *sz) 157 { 158 off_t length, oflow; 159 int lsign; 160 161 length = 0; 162 lsign = 1; 163 164 switch (*ls) { 165 case '-': 166 lsign = -1; 167 case '+': 168 ls++; 169 } 170 171 #define ASSIGN_CHK_OFLOW(x, y) if (x < y) return -1; y = x 172 /* 173 * Calculate the value of the decimal digit string, failing 174 * on overflow. 175 */ 176 while (isdigit(*ls)) { 177 oflow = length * 10 + *ls++ - '0'; 178 ASSIGN_CHK_OFLOW(oflow, length); 179 } 180 181 switch (*ls) { 182 case 'T': 183 case 't': 184 oflow = length * 1024; 185 ASSIGN_CHK_OFLOW(oflow, length); 186 case 'G': 187 case 'g': 188 oflow = length * 1024; 189 ASSIGN_CHK_OFLOW(oflow, length); 190 case 'M': 191 case 'm': 192 oflow = length * 1024; 193 ASSIGN_CHK_OFLOW(oflow, length); 194 case 'K': 195 case 'k': 196 if (ls[1] != '\0') 197 return -1; 198 oflow = length * 1024; 199 ASSIGN_CHK_OFLOW(oflow, length); 200 case '\0': 201 break; 202 default: 203 return -1; 204 } 205 206 *sz = length * lsign; 207 return 0; 208 } 209 210 static void 211 usage(void) 212 { 213 fprintf(stderr, "%s\n%s\n", 214 "usage: truncate [-c] -s [+|-]size[K|k|M|m|G|g|T|t] file ...", 215 " truncate [-c] -r rfile file ..."); 216 exit(EXIT_FAILURE); 217 } 218