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 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 39 __FBSDID("$FreeBSD$"); 40 41 #ifndef lint 42 static const char copyright[] = 43 "@(#) Copyright (c) 1991, 1993\n\ 44 The Regents of the University of California. All rights reserved.\n"; 45 #endif 46 47 #ifndef lint 48 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93"; 49 #endif 50 51 #include <sys/types.h> 52 #include <sys/stat.h> 53 54 #include <err.h> 55 #include <errno.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 61 #include "extern.h" 62 63 int Fflag, fflag, qflag, rflag, rval, no_files; 64 const char *fname; 65 66 file_info_t *files; 67 68 static void obsolete(char **); 69 static void usage(void); 70 71 int 72 main(int argc, char *argv[]) 73 { 74 struct stat sb; 75 FILE *fp; 76 off_t off; 77 enum STYLE style; 78 int i, ch, first; 79 file_info_t *file; 80 char *p; 81 82 /* 83 * Tail's options are weird. First, -n10 is the same as -n-10, not 84 * -n+10. Second, the number options are 1 based and not offsets, 85 * so -n+1 is the first line, and -c-1 is the last byte. Third, the 86 * number options for the -r option specify the number of things that 87 * get displayed, not the starting point in the file. The one major 88 * incompatibility in this version as compared to historical versions 89 * is that the 'r' option couldn't be modified by the -lbc options, 90 * i.e. it was always done in lines. This version treats -rc as a 91 * number of characters in reverse order. Finally, the default for 92 * -r is the entire file, not 10 lines. 93 */ 94 #define ARG(units, forward, backward) { \ 95 if (style) \ 96 usage(); \ 97 off = strtoll(optarg, &p, 10) * (units); \ 98 if (*p) \ 99 errx(1, "illegal offset -- %s", optarg); \ 100 switch(optarg[0]) { \ 101 case '+': \ 102 if (off) \ 103 off -= (units); \ 104 style = (forward); \ 105 break; \ 106 case '-': \ 107 off = -off; \ 108 /* FALLTHROUGH */ \ 109 default: \ 110 style = (backward); \ 111 break; \ 112 } \ 113 } 114 115 obsolete(argv); 116 style = NOTSET; 117 while ((ch = getopt(argc, argv, "Fb:c:fn:qr")) != -1) 118 switch(ch) { 119 case 'F': /* -F is superset of (and implies) -f */ 120 Fflag = fflag = 1; 121 break; 122 case 'b': 123 ARG(512, FBYTES, RBYTES); 124 break; 125 case 'c': 126 ARG(1, FBYTES, RBYTES); 127 break; 128 case 'f': 129 fflag = 1; 130 break; 131 case 'n': 132 ARG(1, FLINES, RLINES); 133 break; 134 case 'q': 135 qflag = 1; 136 break; 137 case 'r': 138 rflag = 1; 139 break; 140 case '?': 141 default: 142 usage(); 143 } 144 argc -= optind; 145 argv += optind; 146 147 no_files = argc ? argc : 1; 148 149 /* 150 * If displaying in reverse, don't permit follow option, and convert 151 * style values. 152 */ 153 if (rflag) { 154 if (fflag) 155 usage(); 156 if (style == FBYTES) 157 style = RBYTES; 158 else if (style == FLINES) 159 style = RLINES; 160 } 161 162 /* 163 * If style not specified, the default is the whole file for -r, and 164 * the last 10 lines if not -r. 165 */ 166 if (style == NOTSET) { 167 if (rflag) { 168 off = 0; 169 style = REVERSE; 170 } else { 171 off = 10; 172 style = RLINES; 173 } 174 } 175 176 if (*argv && fflag) { 177 files = (struct file_info *) malloc(no_files * sizeof(struct file_info)); 178 if (! files) 179 err(1, "Couldn't malloc space for file descriptors."); 180 181 for (file = files; (fname = *argv++); file++) { 182 file->file_name = malloc(strlen(fname)+1); 183 if (! file->file_name) 184 errx(1, "Couldn't malloc space for file name."); 185 strncpy(file->file_name, fname, strlen(fname)+1); 186 if ((file->fp = fopen(file->file_name, "r")) == NULL || 187 fstat(fileno(file->fp), &file->st)) { 188 file->fp = NULL; 189 ierr(); 190 continue; 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; (fname = *argv++);) { 200 if ((fp = fopen(fname, "r")) == NULL || 201 fstat(fileno(fp), &sb)) { 202 ierr(); 203 continue; 204 } 205 if (argc > 1 && !qflag) { 206 (void)printf("%s==> %s <==\n", 207 first ? "" : "\n", fname); 208 first = 0; 209 (void)fflush(stdout); 210 } 211 212 if (rflag) 213 reverse(fp, style, off, &sb); 214 else 215 forward(fp, style, off, &sb); 216 } 217 } else { 218 fname = "stdin"; 219 220 if (fstat(fileno(stdin), &sb)) { 221 ierr(); 222 exit(1); 223 } 224 225 /* 226 * Determine if input is a pipe. 4.4BSD will set the SOCKET 227 * bit in the st_mode field for pipes. Fix this then. 228 */ 229 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 && 230 errno == ESPIPE) { 231 errno = 0; 232 fflag = 0; /* POSIX.2 requires this. */ 233 } 234 235 if (rflag) 236 reverse(stdin, style, off, &sb); 237 else 238 forward(stdin, style, off, &sb); 239 } 240 exit(rval); 241 } 242 243 /* 244 * Convert the obsolete argument form into something that getopt can handle. 245 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't 246 * the option argument for a -b, -c or -n option gets converted. 247 */ 248 static void 249 obsolete(char *argv[]) 250 { 251 char *ap, *p, *t; 252 size_t len; 253 char *start; 254 255 while ((ap = *++argv)) { 256 /* Return if "--" or not an option of any form. */ 257 if (ap[0] != '-') { 258 if (ap[0] != '+') 259 return; 260 } else if (ap[1] == '-') 261 return; 262 263 switch(*++ap) { 264 /* Old-style option. */ 265 case '0': case '1': case '2': case '3': case '4': 266 case '5': case '6': case '7': case '8': case '9': 267 268 /* Malloc space for dash, new option and argument. */ 269 len = strlen(*argv); 270 if ((start = p = malloc(len + 3)) == NULL) 271 err(1, "malloc"); 272 *p++ = '-'; 273 274 /* 275 * Go to the end of the option argument. Save off any 276 * trailing options (-3lf) and translate any trailing 277 * output style characters. 278 */ 279 t = *argv + len - 1; 280 if (*t == 'F' || *t == 'f' || *t == 'r') { 281 *p++ = *t; 282 *t-- = '\0'; 283 } 284 switch(*t) { 285 case 'b': 286 *p++ = 'b'; 287 *t = '\0'; 288 break; 289 case 'c': 290 *p++ = 'c'; 291 *t = '\0'; 292 break; 293 case 'l': 294 *t = '\0'; 295 /* FALLTHROUGH */ 296 case '0': case '1': case '2': case '3': case '4': 297 case '5': case '6': case '7': case '8': case '9': 298 *p++ = 'n'; 299 break; 300 default: 301 errx(1, "illegal option -- %s", *argv); 302 } 303 *p++ = *argv[0]; 304 (void)strcpy(p, ap); 305 *argv = start; 306 continue; 307 308 /* 309 * Options w/ arguments, skip the argument and continue 310 * with the next option. 311 */ 312 case 'b': 313 case 'c': 314 case 'n': 315 if (!ap[1]) 316 ++argv; 317 /* FALLTHROUGH */ 318 /* Options w/o arguments, continue with the next option. */ 319 case 'F': 320 case 'f': 321 case 'r': 322 continue; 323 324 /* Illegal option, return and let getopt handle it. */ 325 default: 326 return; 327 } 328 } 329 } 330 331 static void 332 usage(void) 333 { 334 (void)fprintf(stderr, 335 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]" 336 " [file ...]\n"); 337 exit(1); 338 } 339