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 * $DragonFly: src/usr.bin/truncate/truncate.c,v 1.3 2003/10/04 20:36:53 hmp Exp $ 28 */ 29 30 #include <sys/stat.h> 31 32 #include <ctype.h> 33 #include <err.h> 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <unistd.h> 39 40 static off_t parselength(char *, off_t *); 41 static void usage(void); 42 43 static int no_create; 44 static int do_relative; 45 static int do_refer; 46 static int got_size; 47 48 int 49 main(int argc, char **argv) 50 { 51 struct stat sb; 52 mode_t omode; 53 off_t oflow, rsize, sz, tsize; 54 int ch, error, fd, oflags; 55 char *fname, *rname; 56 57 rsize = tsize = sz = 0; 58 error = 0; 59 rname = NULL; 60 while ((ch = getopt(argc, argv, "cr:s:")) != -1) 61 switch (ch) { 62 case 'c': 63 no_create = 1; 64 break; 65 case 'r': 66 do_refer = 1; 67 rname = optarg; 68 break; 69 case 's': 70 if (parselength(optarg, &sz) == -1) 71 errx(EXIT_FAILURE, 72 "invalid size argument `%s'", optarg); 73 if (*optarg == '+' || *optarg == '-') 74 do_relative = 1; 75 got_size = 1; 76 break; 77 default: 78 usage(); 79 /* NOTREACHED */ 80 } 81 82 argv += optind; 83 argc -= optind; 84 85 /* 86 * Exactly one of do_refer or got_size must be specified. Since 87 * do_relative implies got_size, do_relative and do_refer are 88 * also mutually exclusive. See usage() for allowed invocations. 89 */ 90 if (do_refer + got_size != 1 || argc < 1) 91 usage(); 92 if (do_refer) { 93 if (stat(rname, &sb) == -1) 94 err(EXIT_FAILURE, "%s", rname); 95 tsize = sb.st_size; 96 } else if (do_relative) 97 rsize = sz; 98 else 99 tsize = sz; 100 101 if (no_create) 102 oflags = O_WRONLY; 103 else 104 oflags = O_WRONLY | O_CREAT; 105 omode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH; 106 107 while ((fname = *argv++) != NULL) { 108 if ((fd = open(fname, oflags, omode)) == -1) { 109 if (errno != ENOENT) { 110 warn("%s", fname); 111 error++; 112 } 113 continue; 114 } 115 if (do_relative) { 116 if (fstat(fd, &sb) == -1) { 117 warn("%s", fname); 118 error++; 119 continue; 120 } 121 oflow = sb.st_size + rsize; 122 if (oflow < (sb.st_size + rsize)) { 123 errno = EFBIG; 124 warn("%s", fname); 125 error++; 126 continue; 127 } 128 tsize = oflow; 129 } 130 if (tsize < 0) 131 tsize = 0; 132 133 if (ftruncate(fd, tsize) == -1) { 134 warn("%s", fname); 135 error++; 136 continue; 137 } 138 139 close(fd); 140 } 141 142 return error ? EXIT_FAILURE : EXIT_SUCCESS; 143 } 144 145 /* 146 * Return the numeric value of a string given in the form [+-][0-9]+[GMK] 147 * or -1 on format error or overflow. 148 */ 149 static off_t 150 parselength(char *ls, off_t *sz) 151 { 152 off_t length, oflow; 153 int lsign; 154 155 length = 0; 156 lsign = 1; 157 158 switch (*ls) { 159 case '-': 160 lsign = -1; 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 'G': 177 oflow = length * 1024; 178 ASSIGN_CHK_OFLOW(oflow, length); 179 case 'M': 180 oflow = length * 1024; 181 ASSIGN_CHK_OFLOW(oflow, length); 182 case 'K': 183 if (ls[1] != '\0') 184 return -1; 185 oflow = length * 1024; 186 ASSIGN_CHK_OFLOW(oflow, length); 187 case '\0': 188 break; 189 default: 190 return -1; 191 } 192 193 *sz = length * lsign; 194 return 0; 195 } 196 197 static void 198 usage(void) 199 { 200 fprintf(stderr, "%s\n%s\n", 201 "usage: truncate [-c] -s [+|-]size[K|M|G] file ...", 202 " truncate [-c] -r rfile file ..."); 203 exit(EXIT_FAILURE); 204 } 205