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