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