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 36 #ifndef lint 37 static const char copyright[] = 38 "@(#) Copyright (c) 1991, 1993\n\ 39 The Regents of the University of California. All rights reserved.\n"; 40 #endif 41 42 #ifndef lint 43 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93"; 44 #endif 45 46 #include <sys/capsicum.h> 47 #include <sys/types.h> 48 #include <sys/stat.h> 49 50 #include <capsicum_helpers.h> 51 #include <err.h> 52 #include <errno.h> 53 #include <getopt.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 59 #include <libutil.h> 60 61 #include <libcasper.h> 62 #include <casper/cap_fileargs.h> 63 64 #include "extern.h" 65 66 int Fflag, fflag, qflag, rflag, rval, no_files, vflag; 67 fileargs_t *fa; 68 69 static void obsolete(char **); 70 static void usage(void) __dead2; 71 72 static const struct option long_opts[] = 73 { 74 {"blocks", required_argument, NULL, 'b'}, 75 {"bytes", required_argument, NULL, 'c'}, 76 {"lines", required_argument, NULL, 'n'}, 77 {"quiet", no_argument, NULL, 'q'}, 78 {"silent", no_argument, NULL, 'q'}, 79 {"verbose", no_argument, NULL, 'v'}, 80 {NULL, no_argument, NULL, 0} 81 }; 82 83 int 84 main(int argc, char *argv[]) 85 { 86 struct stat sb; 87 const char *fn; 88 FILE *fp; 89 off_t off; 90 enum STYLE style; 91 int ch, first; 92 file_info_t file, *filep, *files; 93 cap_rights_t rights; 94 95 /* 96 * Tail's options are weird. First, -n10 is the same as -n-10, not 97 * -n+10. Second, the number options are 1 based and not offsets, 98 * so -n+1 is the first line, and -c-1 is the last byte. Third, the 99 * number options for the -r option specify the number of things that 100 * get displayed, not the starting point in the file. The one major 101 * incompatibility in this version as compared to historical versions 102 * is that the 'r' option couldn't be modified by the -lbc options, 103 * i.e. it was always done in lines. This version treats -rc as a 104 * number of characters in reverse order. Finally, the default for 105 * -r is the entire file, not 10 lines. 106 */ 107 #define ARG(units, forward, backward) { \ 108 if (style) \ 109 usage(); \ 110 if (expand_number(optarg, &off)) \ 111 err(1, "illegal offset -- %s", optarg); \ 112 if (off > INT64_MAX / units || off < INT64_MIN / units ) \ 113 errx(1, "illegal offset -- %s", optarg); \ 114 switch(optarg[0]) { \ 115 case '+': \ 116 if (off) \ 117 off -= (units); \ 118 style = (forward); \ 119 break; \ 120 case '-': \ 121 off = -off; \ 122 /* FALLTHROUGH */ \ 123 default: \ 124 style = (backward); \ 125 break; \ 126 } \ 127 } 128 129 obsolete(argv); 130 style = NOTSET; 131 off = 0; 132 while ((ch = getopt_long(argc, argv, "+Fb:c:fn:qrv", long_opts, NULL)) != 133 -1) 134 switch(ch) { 135 case 'F': /* -F is superset of (and implies) -f */ 136 Fflag = fflag = 1; 137 break; 138 case 'b': 139 ARG(512, FBYTES, RBYTES); 140 break; 141 case 'c': 142 ARG(1, FBYTES, RBYTES); 143 break; 144 case 'f': 145 fflag = 1; 146 break; 147 case 'n': 148 ARG(1, FLINES, RLINES); 149 break; 150 case 'q': 151 qflag = 1; 152 vflag = 0; 153 break; 154 case 'r': 155 rflag = 1; 156 break; 157 case 'v': 158 vflag = 1; 159 qflag = 0; 160 break; 161 case '?': 162 default: 163 usage(); 164 } 165 argc -= optind; 166 argv += optind; 167 168 no_files = argc ? argc : 1; 169 170 cap_rights_init(&rights, CAP_FSTAT, CAP_FSTATFS, CAP_FCNTL, 171 CAP_MMAP_R); 172 if (fflag) 173 cap_rights_set(&rights, CAP_EVENT); 174 if (caph_rights_limit(STDIN_FILENO, &rights) < 0 || 175 caph_limit_stderr() < 0 || caph_limit_stdout() < 0) 176 err(1, "can't limit stdio rights"); 177 178 fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN); 179 if (fa == NULL) 180 err(1, "unable to init casper"); 181 182 caph_cache_catpages(); 183 if (caph_enter_casper() < 0) 184 err(1, "unable to enter capability mode"); 185 186 /* 187 * If displaying in reverse, don't permit follow option, and convert 188 * style values. 189 */ 190 if (rflag) { 191 if (fflag) 192 usage(); 193 if (style == FBYTES) 194 style = RBYTES; 195 else if (style == FLINES) 196 style = RLINES; 197 } 198 199 /* 200 * If style not specified, the default is the whole file for -r, and 201 * the last 10 lines if not -r. 202 */ 203 if (style == NOTSET) { 204 if (rflag) { 205 off = 0; 206 style = REVERSE; 207 } else { 208 off = 10; 209 style = RLINES; 210 } 211 } 212 213 if (*argv && fflag) { 214 files = malloc(no_files * sizeof(struct file_info)); 215 if (files == NULL) 216 err(1, "Couldn't malloc space for file descriptors."); 217 218 for (filep = files; (fn = *argv++); filep++) { 219 filep->file_name = fn; 220 filep->fp = fileargs_fopen(fa, filep->file_name, "r"); 221 if (filep->fp == NULL || 222 fstat(fileno(filep->fp), &filep->st)) { 223 if (filep->fp != NULL) { 224 fclose(filep->fp); 225 filep->fp = NULL; 226 } 227 if (!Fflag || errno != ENOENT) 228 ierr(filep->file_name); 229 } 230 } 231 follow(files, style, off); 232 free(files); 233 } else if (*argv) { 234 for (first = 1; (fn = *argv++);) { 235 if ((fp = fileargs_fopen(fa, fn, "r")) == NULL || 236 fstat(fileno(fp), &sb)) { 237 ierr(fn); 238 continue; 239 } 240 if (vflag || (qflag == 0 && argc > 1)) { 241 printfn(fn, !first); 242 first = 0; 243 } 244 245 if (rflag) 246 reverse(fp, fn, style, off, &sb); 247 else 248 forward(fp, fn, style, off, &sb); 249 } 250 } else { 251 fn = "stdin"; 252 253 if (fstat(fileno(stdin), &sb)) { 254 ierr(fn); 255 exit(1); 256 } 257 258 /* 259 * Determine if input is a pipe. 4.4BSD will set the SOCKET 260 * bit in the st_mode field for pipes. Fix this then. 261 */ 262 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 && 263 errno == ESPIPE) { 264 errno = 0; 265 fflag = 0; /* POSIX.2 requires this. */ 266 } 267 268 if (rflag) { 269 reverse(stdin, fn, style, off, &sb); 270 } else if (fflag) { 271 file.file_name = fn; 272 file.fp = stdin; 273 file.st = sb; 274 follow(&file, style, off); 275 } else { 276 forward(stdin, fn, style, off, &sb); 277 } 278 } 279 fileargs_free(fa); 280 exit(rval); 281 } 282 283 /* 284 * Convert the obsolete argument form into something that getopt can handle. 285 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't 286 * the option argument for a -b, -c or -n option gets converted. 287 */ 288 static void 289 obsolete(char *argv[]) 290 { 291 char *ap, *p, *t; 292 size_t len; 293 char *start; 294 295 while ((ap = *++argv)) { 296 /* Return if "--" or not an option of any form. */ 297 if (ap[0] != '-') { 298 if (ap[0] != '+') 299 return; 300 } else if (ap[1] == '-') 301 return; 302 303 switch(*++ap) { 304 /* Old-style option. */ 305 case '0': case '1': case '2': case '3': case '4': 306 case '5': case '6': case '7': case '8': case '9': 307 308 /* Malloc space for dash, new option and argument. */ 309 len = strlen(*argv); 310 if ((start = p = malloc(len + 3)) == NULL) 311 err(1, "malloc"); 312 *p++ = '-'; 313 314 /* 315 * Go to the end of the option argument. Save off any 316 * trailing options (-3lf) and translate any trailing 317 * output style characters. 318 */ 319 t = *argv + len - 1; 320 if (*t == 'F' || *t == 'f' || *t == 'r') { 321 *p++ = *t; 322 *t-- = '\0'; 323 } 324 switch(*t) { 325 case 'b': 326 *p++ = 'b'; 327 *t = '\0'; 328 break; 329 case 'c': 330 *p++ = 'c'; 331 *t = '\0'; 332 break; 333 case 'l': 334 *t = '\0'; 335 /* FALLTHROUGH */ 336 case '0': case '1': case '2': case '3': case '4': 337 case '5': case '6': case '7': case '8': case '9': 338 *p++ = 'n'; 339 break; 340 default: 341 errx(1, "illegal option -- %s", *argv); 342 } 343 *p++ = *argv[0]; 344 (void)strcpy(p, ap); 345 *argv = start; 346 continue; 347 348 /* 349 * Options w/ arguments, skip the argument and continue 350 * with the next option. 351 */ 352 case 'b': 353 case 'c': 354 case 'n': 355 if (!ap[1]) 356 ++argv; 357 /* FALLTHROUGH */ 358 /* Options w/o arguments, continue with the next option. */ 359 case 'F': 360 case 'f': 361 case 'r': 362 continue; 363 364 /* Illegal option, return and let getopt handle it. */ 365 default: 366 return; 367 } 368 } 369 } 370 371 static void 372 usage(void) 373 { 374 (void)fprintf(stderr, 375 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]" 376 " [file ...]\n"); 377 exit(1); 378 } 379