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 file_info_t *files; 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 {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 i, ch, first; 92 file_info_t *file; 93 char *p; 94 cap_rights_t rights; 95 96 /* 97 * Tail's options are weird. First, -n10 is the same as -n-10, not 98 * -n+10. Second, the number options are 1 based and not offsets, 99 * so -n+1 is the first line, and -c-1 is the last byte. Third, the 100 * number options for the -r option specify the number of things that 101 * get displayed, not the starting point in the file. The one major 102 * incompatibility in this version as compared to historical versions 103 * is that the 'r' option couldn't be modified by the -lbc options, 104 * i.e. it was always done in lines. This version treats -rc as a 105 * number of characters in reverse order. Finally, the default for 106 * -r is the entire file, not 10 lines. 107 */ 108 #define ARG(units, forward, backward) { \ 109 if (style) \ 110 usage(); \ 111 off = strtoll(optarg, &p, 10) * (units); \ 112 if (*p) \ 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:qr", 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 break; 153 case 'r': 154 rflag = 1; 155 break; 156 case '?': 157 default: 158 usage(); 159 } 160 argc -= optind; 161 argv += optind; 162 163 no_files = argc ? argc : 1; 164 165 cap_rights_init(&rights, CAP_FSTAT, CAP_FSTATFS, CAP_FCNTL, 166 CAP_MMAP_R); 167 if (fflag) 168 cap_rights_set(&rights, CAP_EVENT); 169 if (caph_rights_limit(STDIN_FILENO, &rights) < 0 || 170 caph_limit_stderr() < 0 || caph_limit_stdout() < 0) 171 err(1, "can't limit stdio rights"); 172 173 fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN); 174 if (fa == NULL) 175 err(1, "unable to init casper"); 176 177 caph_cache_catpages(); 178 if (caph_enter_casper() < 0) 179 err(1, "unable to enter capability mode"); 180 181 /* 182 * If displaying in reverse, don't permit follow option, and convert 183 * style values. 184 */ 185 if (rflag) { 186 if (fflag) 187 usage(); 188 if (style == FBYTES) 189 style = RBYTES; 190 else if (style == FLINES) 191 style = RLINES; 192 } 193 194 /* 195 * If style not specified, the default is the whole file for -r, and 196 * the last 10 lines if not -r. 197 */ 198 if (style == NOTSET) { 199 if (rflag) { 200 off = 0; 201 style = REVERSE; 202 } else { 203 off = 10; 204 style = RLINES; 205 } 206 } 207 208 if (*argv && fflag) { 209 files = (struct file_info *) malloc(no_files * 210 sizeof(struct file_info)); 211 if (!files) 212 err(1, "Couldn't malloc space for file descriptors."); 213 214 for (file = files; (fn = *argv++); file++) { 215 file->file_name = strdup(fn); 216 if (! file->file_name) 217 errx(1, "Couldn't malloc space for file name."); 218 file->fp = fileargs_fopen(fa, file->file_name, "r"); 219 if (file->fp == NULL || 220 fstat(fileno(file->fp), &file->st)) { 221 if (file->fp != NULL) { 222 fclose(file->fp); 223 file->fp = NULL; 224 } 225 if (!Fflag || errno != ENOENT) 226 ierr(file->file_name); 227 } 228 } 229 follow(files, style, off); 230 for (i = 0, file = files; i < no_files; i++, file++) { 231 free(file->file_name); 232 } 233 free(files); 234 } else if (*argv) { 235 for (first = 1; (fn = *argv++);) { 236 if ((fp = fileargs_fopen(fa, fn, "r")) == NULL || 237 fstat(fileno(fp), &sb)) { 238 ierr(fn); 239 continue; 240 } 241 if (argc > 1 && !qflag) { 242 printfn(fn, !first); 243 first = 0; 244 } 245 246 if (rflag) 247 reverse(fp, fn, style, off, &sb); 248 else 249 forward(fp, fn, style, off, &sb); 250 } 251 } else { 252 fn = "stdin"; 253 254 if (fstat(fileno(stdin), &sb)) { 255 ierr(fn); 256 exit(1); 257 } 258 259 /* 260 * Determine if input is a pipe. 4.4BSD will set the SOCKET 261 * bit in the st_mode field for pipes. Fix this then. 262 */ 263 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 && 264 errno == ESPIPE) { 265 errno = 0; 266 fflag = 0; /* POSIX.2 requires this. */ 267 } 268 269 if (rflag) 270 reverse(stdin, fn, style, off, &sb); 271 else 272 forward(stdin, fn, style, off, &sb); 273 } 274 fileargs_free(fa); 275 exit(rval); 276 } 277 278 /* 279 * Convert the obsolete argument form into something that getopt can handle. 280 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't 281 * the option argument for a -b, -c or -n option gets converted. 282 */ 283 static void 284 obsolete(char *argv[]) 285 { 286 char *ap, *p, *t; 287 size_t len; 288 char *start; 289 290 while ((ap = *++argv)) { 291 /* Return if "--" or not an option of any form. */ 292 if (ap[0] != '-') { 293 if (ap[0] != '+') 294 return; 295 } else if (ap[1] == '-') 296 return; 297 298 switch(*++ap) { 299 /* Old-style option. */ 300 case '0': case '1': case '2': case '3': case '4': 301 case '5': case '6': case '7': case '8': case '9': 302 303 /* Malloc space for dash, new option and argument. */ 304 len = strlen(*argv); 305 if ((start = p = malloc(len + 3)) == NULL) 306 err(1, "malloc"); 307 *p++ = '-'; 308 309 /* 310 * Go to the end of the option argument. Save off any 311 * trailing options (-3lf) and translate any trailing 312 * output style characters. 313 */ 314 t = *argv + len - 1; 315 if (*t == 'F' || *t == 'f' || *t == 'r') { 316 *p++ = *t; 317 *t-- = '\0'; 318 } 319 switch(*t) { 320 case 'b': 321 *p++ = 'b'; 322 *t = '\0'; 323 break; 324 case 'c': 325 *p++ = 'c'; 326 *t = '\0'; 327 break; 328 case 'l': 329 *t = '\0'; 330 /* FALLTHROUGH */ 331 case '0': case '1': case '2': case '3': case '4': 332 case '5': case '6': case '7': case '8': case '9': 333 *p++ = 'n'; 334 break; 335 default: 336 errx(1, "illegal option -- %s", *argv); 337 } 338 *p++ = *argv[0]; 339 (void)strcpy(p, ap); 340 *argv = start; 341 continue; 342 343 /* 344 * Options w/ arguments, skip the argument and continue 345 * with the next option. 346 */ 347 case 'b': 348 case 'c': 349 case 'n': 350 if (!ap[1]) 351 ++argv; 352 /* FALLTHROUGH */ 353 /* Options w/o arguments, continue with the next option. */ 354 case 'F': 355 case 'f': 356 case 'r': 357 continue; 358 359 /* Illegal option, return and let getopt handle it. */ 360 default: 361 return; 362 } 363 } 364 } 365 366 static void 367 usage(void) 368 { 369 (void)fprintf(stderr, 370 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]" 371 " [file ...]\n"); 372 exit(1); 373 } 374