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