1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Edward Sze-Tyan Wang. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 37 __FBSDID("$FreeBSD$"); 38 39 #ifndef lint 40 static const char copyright[] = 41 "@(#) Copyright (c) 1991, 1993\n\ 42 The Regents of the University of California. All rights reserved.\n"; 43 #endif 44 45 #ifndef lint 46 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93"; 47 #endif 48 49 #include <sys/capsicum.h> 50 #include <sys/types.h> 51 #include <sys/stat.h> 52 53 #include <capsicum_helpers.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <getopt.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <unistd.h> 61 62 #include <libutil.h> 63 64 #include <libcasper.h> 65 #include <casper/cap_fileargs.h> 66 67 #include "extern.h" 68 69 int Fflag, fflag, qflag, rflag, rval, no_files, vflag; 70 fileargs_t *fa; 71 72 static void obsolete(char **); 73 static void usage(void); 74 75 static const struct option long_opts[] = 76 { 77 {"blocks", required_argument, NULL, 'b'}, 78 {"bytes", required_argument, NULL, 'c'}, 79 {"lines", required_argument, NULL, 'n'}, 80 {"quiet", no_argument, NULL, 'q'}, 81 {"silent", no_argument, NULL, 'q'}, 82 {"verbose", no_argument, NULL, 'v'}, 83 {NULL, no_argument, NULL, 0} 84 }; 85 86 int 87 main(int argc, char *argv[]) 88 { 89 struct stat sb; 90 const char *fn; 91 FILE *fp; 92 off_t off; 93 enum STYLE style; 94 int ch, first; 95 file_info_t file, *filep, *files; 96 cap_rights_t rights; 97 98 /* 99 * Tail's options are weird. First, -n10 is the same as -n-10, not 100 * -n+10. Second, the number options are 1 based and not offsets, 101 * so -n+1 is the first line, and -c-1 is the last byte. Third, the 102 * number options for the -r option specify the number of things that 103 * get displayed, not the starting point in the file. The one major 104 * incompatibility in this version as compared to historical versions 105 * is that the 'r' option couldn't be modified by the -lbc options, 106 * i.e. it was always done in lines. This version treats -rc as a 107 * number of characters in reverse order. Finally, the default for 108 * -r is the entire file, not 10 lines. 109 */ 110 #define ARG(units, forward, backward) { \ 111 if (style) \ 112 usage(); \ 113 if (expand_number(optarg, &off)) \ 114 err(1, "illegal offset -- %s", optarg); \ 115 if (off > INT64_MAX / units || off < INT64_MIN / units ) \ 116 errx(1, "illegal offset -- %s", optarg); \ 117 switch(optarg[0]) { \ 118 case '+': \ 119 if (off) \ 120 off -= (units); \ 121 style = (forward); \ 122 break; \ 123 case '-': \ 124 off = -off; \ 125 /* FALLTHROUGH */ \ 126 default: \ 127 style = (backward); \ 128 break; \ 129 } \ 130 } 131 132 obsolete(argv); 133 style = NOTSET; 134 off = 0; 135 while ((ch = getopt_long(argc, argv, "+Fb:c:fn:qrv", long_opts, NULL)) != 136 -1) 137 switch(ch) { 138 case 'F': /* -F is superset of (and implies) -f */ 139 Fflag = fflag = 1; 140 break; 141 case 'b': 142 ARG(512, FBYTES, RBYTES); 143 break; 144 case 'c': 145 ARG(1, FBYTES, RBYTES); 146 break; 147 case 'f': 148 fflag = 1; 149 break; 150 case 'n': 151 ARG(1, FLINES, RLINES); 152 break; 153 case 'q': 154 qflag = 1; 155 vflag = 0; 156 break; 157 case 'r': 158 rflag = 1; 159 break; 160 case 'v': 161 vflag = 1; 162 qflag = 0; 163 break; 164 case '?': 165 default: 166 usage(); 167 } 168 argc -= optind; 169 argv += optind; 170 171 no_files = argc ? argc : 1; 172 173 cap_rights_init(&rights, CAP_FSTAT, CAP_FSTATFS, CAP_FCNTL, 174 CAP_MMAP_R); 175 if (fflag) 176 cap_rights_set(&rights, CAP_EVENT); 177 if (caph_rights_limit(STDIN_FILENO, &rights) < 0 || 178 caph_limit_stderr() < 0 || caph_limit_stdout() < 0) 179 err(1, "can't limit stdio rights"); 180 181 fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN); 182 if (fa == NULL) 183 err(1, "unable to init casper"); 184 185 caph_cache_catpages(); 186 if (caph_enter_casper() < 0) 187 err(1, "unable to enter capability mode"); 188 189 /* 190 * If displaying in reverse, don't permit follow option, and convert 191 * style values. 192 */ 193 if (rflag) { 194 if (fflag) 195 usage(); 196 if (style == FBYTES) 197 style = RBYTES; 198 else if (style == FLINES) 199 style = RLINES; 200 } 201 202 /* 203 * If style not specified, the default is the whole file for -r, and 204 * the last 10 lines if not -r. 205 */ 206 if (style == NOTSET) { 207 if (rflag) { 208 off = 0; 209 style = REVERSE; 210 } else { 211 off = 10; 212 style = RLINES; 213 } 214 } 215 216 if (*argv && fflag) { 217 files = malloc(no_files * sizeof(struct file_info)); 218 if (files == NULL) 219 err(1, "Couldn't malloc space for file descriptors."); 220 221 for (filep = files; (fn = *argv++); filep++) { 222 filep->file_name = fn; 223 filep->fp = fileargs_fopen(fa, filep->file_name, "r"); 224 if (filep->fp == NULL || 225 fstat(fileno(filep->fp), &filep->st)) { 226 if (filep->fp != NULL) { 227 fclose(filep->fp); 228 filep->fp = NULL; 229 } 230 if (!Fflag || errno != ENOENT) 231 ierr(filep->file_name); 232 } 233 } 234 follow(files, style, off); 235 free(files); 236 } else if (*argv) { 237 for (first = 1; (fn = *argv++);) { 238 if ((fp = fileargs_fopen(fa, fn, "r")) == NULL || 239 fstat(fileno(fp), &sb)) { 240 ierr(fn); 241 continue; 242 } 243 if (vflag || (qflag == 0 && argc > 1)) { 244 printfn(fn, !first); 245 first = 0; 246 } 247 248 if (rflag) 249 reverse(fp, fn, style, off, &sb); 250 else 251 forward(fp, fn, style, off, &sb); 252 } 253 } else { 254 fn = "stdin"; 255 256 if (fstat(fileno(stdin), &sb)) { 257 ierr(fn); 258 exit(1); 259 } 260 261 /* 262 * Determine if input is a pipe. 4.4BSD will set the SOCKET 263 * bit in the st_mode field for pipes. Fix this then. 264 */ 265 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 && 266 errno == ESPIPE) { 267 errno = 0; 268 fflag = 0; /* POSIX.2 requires this. */ 269 } 270 271 if (rflag) { 272 reverse(stdin, fn, style, off, &sb); 273 } else if (fflag) { 274 file.file_name = fn; 275 file.fp = stdin; 276 file.st = sb; 277 follow(&file, style, off); 278 } else { 279 forward(stdin, fn, style, off, &sb); 280 } 281 } 282 fileargs_free(fa); 283 exit(rval); 284 } 285 286 /* 287 * Convert the obsolete argument form into something that getopt can handle. 288 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't 289 * the option argument for a -b, -c or -n option gets converted. 290 */ 291 static void 292 obsolete(char *argv[]) 293 { 294 char *ap, *p, *t; 295 size_t len; 296 char *start; 297 298 while ((ap = *++argv)) { 299 /* Return if "--" or not an option of any form. */ 300 if (ap[0] != '-') { 301 if (ap[0] != '+') 302 return; 303 } else if (ap[1] == '-') 304 return; 305 306 switch(*++ap) { 307 /* Old-style option. */ 308 case '0': case '1': case '2': case '3': case '4': 309 case '5': case '6': case '7': case '8': case '9': 310 311 /* Malloc space for dash, new option and argument. */ 312 len = strlen(*argv); 313 if ((start = p = malloc(len + 3)) == NULL) 314 err(1, "malloc"); 315 *p++ = '-'; 316 317 /* 318 * Go to the end of the option argument. Save off any 319 * trailing options (-3lf) and translate any trailing 320 * output style characters. 321 */ 322 t = *argv + len - 1; 323 if (*t == 'F' || *t == 'f' || *t == 'r') { 324 *p++ = *t; 325 *t-- = '\0'; 326 } 327 switch(*t) { 328 case 'b': 329 *p++ = 'b'; 330 *t = '\0'; 331 break; 332 case 'c': 333 *p++ = 'c'; 334 *t = '\0'; 335 break; 336 case 'l': 337 *t = '\0'; 338 /* FALLTHROUGH */ 339 case '0': case '1': case '2': case '3': case '4': 340 case '5': case '6': case '7': case '8': case '9': 341 *p++ = 'n'; 342 break; 343 default: 344 errx(1, "illegal option -- %s", *argv); 345 } 346 *p++ = *argv[0]; 347 (void)strcpy(p, ap); 348 *argv = start; 349 continue; 350 351 /* 352 * Options w/ arguments, skip the argument and continue 353 * with the next option. 354 */ 355 case 'b': 356 case 'c': 357 case 'n': 358 if (!ap[1]) 359 ++argv; 360 /* FALLTHROUGH */ 361 /* Options w/o arguments, continue with the next option. */ 362 case 'F': 363 case 'f': 364 case 'r': 365 continue; 366 367 /* Illegal option, return and let getopt handle it. */ 368 default: 369 return; 370 } 371 } 372 } 373 374 static void 375 usage(void) 376 { 377 (void)fprintf(stderr, 378 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]" 379 " [file ...]\n"); 380 exit(1); 381 } 382