1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Edward Sze-Tyan Wang. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 35 __FBSDID("$FreeBSD$"); 36 37 #ifndef lint 38 static const char copyright[] = 39 "@(#) Copyright (c) 1991, 1993\n\ 40 The Regents of the University of California. All rights reserved.\n"; 41 #endif 42 43 #ifndef lint 44 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93"; 45 #endif 46 47 #include <sys/types.h> 48 #include <sys/stat.h> 49 50 #include <err.h> 51 #include <errno.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 #include "extern.h" 58 59 int Fflag, fflag, qflag, rflag, rval, no_files; 60 61 static file_info_t *files; 62 63 static void obsolete(char **); 64 static void usage(void); 65 66 int 67 main(int argc, char *argv[]) 68 { 69 struct stat sb; 70 const char *fn; 71 FILE *fp; 72 off_t off; 73 enum STYLE style; 74 int i, ch, first; 75 file_info_t *file; 76 char *p; 77 78 /* 79 * Tail's options are weird. First, -n10 is the same as -n-10, not 80 * -n+10. Second, the number options are 1 based and not offsets, 81 * so -n+1 is the first line, and -c-1 is the last byte. Third, the 82 * number options for the -r option specify the number of things that 83 * get displayed, not the starting point in the file. The one major 84 * incompatibility in this version as compared to historical versions 85 * is that the 'r' option couldn't be modified by the -lbc options, 86 * i.e. it was always done in lines. This version treats -rc as a 87 * number of characters in reverse order. Finally, the default for 88 * -r is the entire file, not 10 lines. 89 */ 90 #define ARG(units, forward, backward) { \ 91 if (style) \ 92 usage(); \ 93 off = strtoll(optarg, &p, 10) * (units); \ 94 if (*p) \ 95 errx(1, "illegal offset -- %s", optarg); \ 96 switch(optarg[0]) { \ 97 case '+': \ 98 if (off) \ 99 off -= (units); \ 100 style = (forward); \ 101 break; \ 102 case '-': \ 103 off = -off; \ 104 /* FALLTHROUGH */ \ 105 default: \ 106 style = (backward); \ 107 break; \ 108 } \ 109 } 110 111 obsolete(argv); 112 style = NOTSET; 113 off = 0; 114 while ((ch = getopt(argc, argv, "Fb:c:fn:qr")) != -1) 115 switch(ch) { 116 case 'F': /* -F is superset of (and implies) -f */ 117 Fflag = fflag = 1; 118 break; 119 case 'b': 120 ARG(512, FBYTES, RBYTES); 121 break; 122 case 'c': 123 ARG(1, FBYTES, RBYTES); 124 break; 125 case 'f': 126 fflag = 1; 127 break; 128 case 'n': 129 ARG(1, FLINES, RLINES); 130 break; 131 case 'q': 132 qflag = 1; 133 break; 134 case 'r': 135 rflag = 1; 136 break; 137 case '?': 138 default: 139 usage(); 140 } 141 argc -= optind; 142 argv += optind; 143 144 no_files = argc ? argc : 1; 145 146 /* 147 * If displaying in reverse, don't permit follow option, and convert 148 * style values. 149 */ 150 if (rflag) { 151 if (fflag) 152 usage(); 153 if (style == FBYTES) 154 style = RBYTES; 155 else if (style == FLINES) 156 style = RLINES; 157 } 158 159 /* 160 * If style not specified, the default is the whole file for -r, and 161 * the last 10 lines if not -r. 162 */ 163 if (style == NOTSET) { 164 if (rflag) { 165 off = 0; 166 style = REVERSE; 167 } else { 168 off = 10; 169 style = RLINES; 170 } 171 } 172 173 if (*argv && fflag) { 174 files = (struct file_info *) malloc(no_files * 175 sizeof(struct file_info)); 176 if (!files) 177 err(1, "Couldn't malloc space for file descriptors."); 178 179 for (file = files; (fn = *argv++); file++) { 180 file->file_name = strdup(fn); 181 if (! file->file_name) 182 errx(1, "Couldn't malloc space for file name."); 183 if ((file->fp = fopen(file->file_name, "r")) == NULL || 184 fstat(fileno(file->fp), &file->st)) { 185 if (file->fp != NULL) { 186 fclose(file->fp); 187 file->fp = NULL; 188 } 189 if (!Fflag || errno != ENOENT) 190 ierr(file->file_name); 191 } 192 } 193 follow(files, style, off); 194 for (i = 0, file = files; i < no_files; i++, file++) { 195 free(file->file_name); 196 } 197 free(files); 198 } else if (*argv) { 199 for (first = 1; (fn = *argv++);) { 200 if ((fp = fopen(fn, "r")) == NULL || 201 fstat(fileno(fp), &sb)) { 202 ierr(fn); 203 continue; 204 } 205 if (argc > 1 && !qflag) { 206 printfn(fn, !first); 207 first = 0; 208 } 209 210 if (rflag) 211 reverse(fp, fn, style, off, &sb); 212 else 213 forward(fp, fn, style, off, &sb); 214 } 215 } else { 216 fn = "stdin"; 217 218 if (fstat(fileno(stdin), &sb)) { 219 ierr(fn); 220 exit(1); 221 } 222 223 /* 224 * Determine if input is a pipe. 4.4BSD will set the SOCKET 225 * bit in the st_mode field for pipes. Fix this then. 226 */ 227 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 && 228 errno == ESPIPE) { 229 errno = 0; 230 fflag = 0; /* POSIX.2 requires this. */ 231 } 232 233 if (rflag) 234 reverse(stdin, fn, style, off, &sb); 235 else 236 forward(stdin, fn, style, off, &sb); 237 } 238 exit(rval); 239 } 240 241 /* 242 * Convert the obsolete argument form into something that getopt can handle. 243 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't 244 * the option argument for a -b, -c or -n option gets converted. 245 */ 246 static void 247 obsolete(char *argv[]) 248 { 249 char *ap, *p, *t; 250 size_t len; 251 char *start; 252 253 while ((ap = *++argv)) { 254 /* Return if "--" or not an option of any form. */ 255 if (ap[0] != '-') { 256 if (ap[0] != '+') 257 return; 258 } else if (ap[1] == '-') 259 return; 260 261 switch(*++ap) { 262 /* Old-style option. */ 263 case '0': case '1': case '2': case '3': case '4': 264 case '5': case '6': case '7': case '8': case '9': 265 266 /* Malloc space for dash, new option and argument. */ 267 len = strlen(*argv); 268 if ((start = p = malloc(len + 3)) == NULL) 269 err(1, "malloc"); 270 *p++ = '-'; 271 272 /* 273 * Go to the end of the option argument. Save off any 274 * trailing options (-3lf) and translate any trailing 275 * output style characters. 276 */ 277 t = *argv + len - 1; 278 if (*t == 'F' || *t == 'f' || *t == 'r') { 279 *p++ = *t; 280 *t-- = '\0'; 281 } 282 switch(*t) { 283 case 'b': 284 *p++ = 'b'; 285 *t = '\0'; 286 break; 287 case 'c': 288 *p++ = 'c'; 289 *t = '\0'; 290 break; 291 case 'l': 292 *t = '\0'; 293 /* FALLTHROUGH */ 294 case '0': case '1': case '2': case '3': case '4': 295 case '5': case '6': case '7': case '8': case '9': 296 *p++ = 'n'; 297 break; 298 default: 299 errx(1, "illegal option -- %s", *argv); 300 } 301 *p++ = *argv[0]; 302 (void)strcpy(p, ap); 303 *argv = start; 304 continue; 305 306 /* 307 * Options w/ arguments, skip the argument and continue 308 * with the next option. 309 */ 310 case 'b': 311 case 'c': 312 case 'n': 313 if (!ap[1]) 314 ++argv; 315 /* FALLTHROUGH */ 316 /* Options w/o arguments, continue with the next option. */ 317 case 'F': 318 case 'f': 319 case 'r': 320 continue; 321 322 /* Illegal option, return and let getopt handle it. */ 323 default: 324 return; 325 } 326 } 327 } 328 329 static void 330 usage(void) 331 { 332 (void)fprintf(stderr, 333 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]" 334 " [file ...]\n"); 335 exit(1); 336 } 337