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 * @(#) Copyright (c) 1991, 1993 The Regents of the University of California. All rights reserved. 37 * @(#)tail.c 8.1 (Berkeley) 6/6/93 38 * $FreeBSD: src/usr.bin/tail/tail.c,v 1.6.2.2 2001/12/19 20:29:31 iedowse Exp $ 39 * $DragonFly: src/usr.bin/tail/tail.c,v 1.6 2005/03/01 21:37:33 cpressey Exp $ 40 */ 41 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 #include <errno.h> 45 #include <unistd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <err.h> 50 #include "extern.h" 51 52 int Fflag, fflag, rflag, rval, no_files; 53 const char *fname; 54 55 file_info_t *files; 56 57 static void obsolete(char **); 58 static void usage(void); 59 static void getarg(int, enum STYLE, enum STYLE, enum STYLE *, int *, off_t *); 60 61 int 62 main(int argc, char **argv) 63 { 64 struct stat sb; 65 FILE *fp; 66 off_t off = 0; 67 enum STYLE style; 68 int style_set; 69 int i, ch; 70 file_info_t *file; 71 72 obsolete(argv); 73 style_set = 0; 74 while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1) 75 switch(ch) { 76 case 'F': /* -F is superset of (and implies) -f */ 77 Fflag = fflag = 1; 78 break; 79 case 'b': 80 getarg(512, FBYTES, RBYTES, &style, &style_set, &off); 81 break; 82 case 'c': 83 getarg(1, FBYTES, RBYTES, &style, &style_set, &off); 84 break; 85 case 'f': 86 fflag = 1; 87 break; 88 case 'n': 89 getarg(1, FLINES, RLINES, &style, &style_set, &off); 90 break; 91 case 'r': 92 rflag = 1; 93 break; 94 case '?': 95 default: 96 usage(); 97 } 98 argc -= optind; 99 argv += optind; 100 101 no_files = argc ? argc : 1; 102 103 /* 104 * If displaying in reverse, don't permit follow option, and convert 105 * style values. 106 */ 107 if (rflag) { 108 if (fflag) 109 usage(); 110 if (style == FBYTES) 111 style = RBYTES; 112 else if (style == FLINES) 113 style = RLINES; 114 } 115 116 /* 117 * If style not specified, the default is the whole file for -r, and 118 * the last 10 lines if not -r. 119 */ 120 if (!style_set) { 121 if (rflag) { 122 off = 0; 123 style = REVERSE; 124 } else { 125 off = 10; 126 style = RLINES; 127 } 128 } 129 130 if (*argv && fflag) { 131 files = malloc(no_files * sizeof(struct file_info)); 132 if (files == NULL) 133 err(1, "Couldn't malloc space for files descriptors."); 134 135 for (file = files; (fname = *argv++) != NULL; file++) { 136 file->file_name = strdup(fname); 137 if (! file->file_name) 138 errx(1, "Couldn't alloc space for file name."); 139 file->fp = fopen(file->file_name, "r"); 140 if (file->fp == NULL || 141 fstat(fileno(file->fp), &file->st) == -1) { 142 file->fp = NULL; 143 ierr(); 144 continue; 145 } 146 } 147 follow(files, style, off); 148 for (i = 0, file = files; i < no_files; i++, file++) 149 free(file->file_name); 150 free(files); 151 } else if (*argv) { 152 for (i = 0; (fname = *argv++) != NULL; ++i) { 153 if ((fp = fopen(fname, "r")) == NULL || 154 fstat(fileno(fp), &sb)) { 155 ierr(); 156 continue; 157 } 158 if (argc > 1) { 159 showfilename(i, fname); 160 (void)fflush(stdout); 161 } 162 163 if (rflag) 164 reverse(fp, style, off, &sb); 165 else 166 forward(fp, style, off, &sb); 167 (void)fclose(fp); 168 } 169 } else { 170 fname = "stdin"; 171 172 if (fstat(fileno(stdin), &sb)) { 173 ierr(); 174 exit(1); 175 } 176 177 /* 178 * Determine if input is a pipe. 4.4BSD will set the SOCKET 179 * bit in the st_mode field for pipes. Fix this then. 180 */ 181 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 && 182 errno == ESPIPE) { 183 errno = 0; 184 fflag = 0; /* POSIX.2 requires this. */ 185 } 186 187 if (rflag) 188 reverse(stdin, style, off, &sb); 189 else 190 forward(stdin, style, off, &sb); 191 } 192 exit(rval); 193 } 194 195 /* 196 * Tail's options are weird. First, -n10 is the same as -n-10, not 197 * -n+10. Second, the number options are 1 based and not offsets, 198 * so -n+1 is the first line, and -c-1 is the last byte. Third, the 199 * number options for the -r option specify the number of things that 200 * get displayed, not the starting point in the file. The one major 201 * incompatibility in this version as compared to historical versions 202 * is that the 'r' option couldn't be modified by the -lbc options, 203 * i.e. it was always done in lines. This version treats -rc as a 204 * number of characters in reverse order. Finally, the default for 205 * -r is the entire file, not 10 lines. 206 */ 207 static void 208 getarg(int units, enum STYLE forward_style, enum STYLE backward_style, 209 enum STYLE *style, int *style_set, off_t *off) 210 { 211 char *p; 212 213 if (*style_set) 214 usage(); 215 216 *off = strtoll(optarg, &p, 10) * units; 217 if (*p != '\0') 218 errx(1, "illegal offset -- %s", optarg); 219 switch (optarg[0]) { 220 case '+': 221 if (*off != 0) 222 *off -= (units); 223 *style = forward_style; 224 break; 225 case '-': 226 *off = -*off; 227 /* FALLTHROUGH */ 228 default: 229 *style = backward_style; 230 break; 231 } 232 233 *style_set = 1; 234 } 235 236 /* 237 * Convert the obsolete argument form into something that getopt can handle. 238 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't 239 * the option argument for a -b, -c or -n option gets converted. 240 */ 241 static void 242 obsolete(char **argv) 243 { 244 char *ap, *p, *t; 245 size_t len; 246 char *start; 247 248 while ((ap = *++argv) != NULL) { 249 /* Return if "--" or not an option of any form. */ 250 if (ap[0] != '-') { 251 if (ap[0] != '+') 252 return; 253 } else if (ap[1] == '-') 254 return; 255 256 switch(*++ap) { 257 /* Old-style option. */ 258 case '0': case '1': case '2': case '3': case '4': 259 case '5': case '6': case '7': case '8': case '9': 260 261 /* Malloc space for dash, new option and argument. */ 262 len = strlen(*argv); 263 if ((start = p = malloc(len + 3)) == NULL) 264 err(1, "malloc"); 265 *p++ = '-'; 266 267 /* 268 * Go to the end of the option argument. Save off any 269 * trailing options (-3lf) and translate any trailing 270 * output style characters. 271 */ 272 t = *argv + len - 1; 273 if (*t == 'F' || *t == 'f' || *t == 'r') { 274 *p++ = *t; 275 *t-- = '\0'; 276 } 277 switch(*t) { 278 case 'b': 279 *p++ = 'b'; 280 *t = '\0'; 281 break; 282 case 'c': 283 *p++ = 'c'; 284 *t = '\0'; 285 break; 286 case 'l': 287 *t = '\0'; 288 /* FALLTHROUGH */ 289 case '0': case '1': case '2': case '3': case '4': 290 case '5': case '6': case '7': case '8': case '9': 291 *p++ = 'n'; 292 break; 293 default: 294 errx(1, "illegal option -- %s", *argv); 295 } 296 *p++ = *argv[0]; 297 (void)strcpy(p, ap); 298 *argv = start; 299 continue; 300 301 /* 302 * Options w/ arguments, skip the argument and continue 303 * with the next option. 304 */ 305 case 'b': 306 case 'c': 307 case 'n': 308 if (!ap[1]) 309 ++argv; 310 /* FALLTHROUGH */ 311 /* Options w/o arguments, continue with the next option. */ 312 case 'F': 313 case 'f': 314 case 'r': 315 continue; 316 317 /* Illegal option, return and let getopt handle it. */ 318 default: 319 return; 320 } 321 } 322 } 323 324 static void 325 usage(void) 326 { 327 (void)fprintf(stderr, 328 "usage: tail [-F | -f | -r] [-b # | -c # | -n #] [file ...]\n"); 329 exit(1); 330 } 331