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. 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 * @(#) Copyright (c) 1991, 1993 The Regents of the University of California. All rights reserved. 33 * @(#)tail.c 8.1 (Berkeley) 6/6/93 34 * $FreeBSD: src/usr.bin/tail/tail.c,v 1.6.2.2 2001/12/19 20:29:31 iedowse Exp $ 35 * $DragonFly: src/usr.bin/tail/tail.c,v 1.6 2005/03/01 21:37:33 cpressey Exp $ 36 */ 37 38 #include <sys/types.h> 39 #include <sys/stat.h> 40 #include <errno.h> 41 #include <unistd.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <err.h> 46 #include "extern.h" 47 48 int Fflag, fflag, rflag, rval, no_files; 49 const char *fname; 50 51 file_info_t *files; 52 53 static void obsolete(char **); 54 static void usage(void); 55 static void getarg(int, enum STYLE, enum STYLE, enum STYLE *, int *, off_t *); 56 57 int 58 main(int argc, char **argv) 59 { 60 struct stat sb; 61 FILE *fp; 62 off_t off = 0; 63 enum STYLE style; 64 int style_set; 65 int i, ch; 66 file_info_t *file; 67 68 obsolete(argv); 69 style_set = 0; 70 while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1) 71 switch(ch) { 72 case 'F': /* -F is superset of (and implies) -f */ 73 Fflag = fflag = 1; 74 break; 75 case 'b': 76 getarg(512, FBYTES, RBYTES, &style, &style_set, &off); 77 break; 78 case 'c': 79 getarg(1, FBYTES, RBYTES, &style, &style_set, &off); 80 break; 81 case 'f': 82 fflag = 1; 83 break; 84 case 'n': 85 getarg(1, FLINES, RLINES, &style, &style_set, &off); 86 break; 87 case 'r': 88 rflag = 1; 89 break; 90 case '?': 91 default: 92 usage(); 93 } 94 argc -= optind; 95 argv += optind; 96 97 no_files = argc ? argc : 1; 98 99 /* 100 * If displaying in reverse, don't permit follow option, and convert 101 * style values. 102 */ 103 if (rflag) { 104 if (fflag) 105 usage(); 106 if (style == FBYTES) 107 style = RBYTES; 108 else if (style == FLINES) 109 style = RLINES; 110 } 111 112 /* 113 * If style not specified, the default is the whole file for -r, and 114 * the last 10 lines if not -r. 115 */ 116 if (!style_set) { 117 if (rflag) { 118 off = 0; 119 style = REVERSE; 120 } else { 121 off = 10; 122 style = RLINES; 123 } 124 } 125 126 if (*argv && fflag) { 127 files = malloc(no_files * sizeof(struct file_info)); 128 if (files == NULL) 129 err(1, "Couldn't malloc space for files descriptors."); 130 131 for (file = files; (fname = *argv++) != NULL; file++) { 132 file->file_name = strdup(fname); 133 if (! file->file_name) 134 errx(1, "Couldn't alloc space for file name."); 135 file->fp = fopen(file->file_name, "r"); 136 if (file->fp == NULL || 137 fstat(fileno(file->fp), &file->st) == -1) { 138 file->fp = NULL; 139 ierr(); 140 continue; 141 } 142 } 143 follow(files, style, off); 144 for (i = 0, file = files; i < no_files; i++, file++) 145 free(file->file_name); 146 free(files); 147 } else if (*argv) { 148 for (i = 0; (fname = *argv++) != NULL; ++i) { 149 if ((fp = fopen(fname, "r")) == NULL || 150 fstat(fileno(fp), &sb)) { 151 ierr(); 152 continue; 153 } 154 if (argc > 1) { 155 showfilename(i, fname); 156 (void)fflush(stdout); 157 } 158 159 if (rflag) 160 reverse(fp, style, off, &sb); 161 else 162 forward(fp, style, off, &sb); 163 (void)fclose(fp); 164 } 165 } else { 166 fname = "stdin"; 167 168 if (fstat(fileno(stdin), &sb)) { 169 ierr(); 170 exit(1); 171 } 172 173 /* 174 * Determine if input is a pipe. 4.4BSD will set the SOCKET 175 * bit in the st_mode field for pipes. Fix this then. 176 */ 177 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 && 178 errno == ESPIPE) { 179 errno = 0; 180 fflag = 0; /* POSIX.2 requires this. */ 181 } 182 183 if (rflag) 184 reverse(stdin, style, off, &sb); 185 else 186 forward(stdin, style, off, &sb); 187 } 188 exit(rval); 189 } 190 191 /* 192 * Tail's options are weird. First, -n10 is the same as -n-10, not 193 * -n+10. Second, the number options are 1 based and not offsets, 194 * so -n+1 is the first line, and -c-1 is the last byte. Third, the 195 * number options for the -r option specify the number of things that 196 * get displayed, not the starting point in the file. The one major 197 * incompatibility in this version as compared to historical versions 198 * is that the 'r' option couldn't be modified by the -lbc options, 199 * i.e. it was always done in lines. This version treats -rc as a 200 * number of characters in reverse order. Finally, the default for 201 * -r is the entire file, not 10 lines. 202 */ 203 static void 204 getarg(int units, enum STYLE forward_style, enum STYLE backward_style, 205 enum STYLE *style, int *style_set, off_t *off) 206 { 207 char *p; 208 209 if (*style_set) 210 usage(); 211 212 *off = strtoll(optarg, &p, 10) * units; 213 if (*p != '\0') 214 errx(1, "illegal offset -- %s", optarg); 215 switch (optarg[0]) { 216 case '+': 217 if (*off != 0) 218 *off -= (units); 219 *style = forward_style; 220 break; 221 case '-': 222 *off = -*off; 223 /* FALLTHROUGH */ 224 default: 225 *style = backward_style; 226 break; 227 } 228 229 *style_set = 1; 230 } 231 232 /* 233 * Convert the obsolete argument form into something that getopt can handle. 234 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't 235 * the option argument for a -b, -c or -n option gets converted. 236 */ 237 static void 238 obsolete(char **argv) 239 { 240 char *ap, *p, *t; 241 size_t len; 242 char *start; 243 244 while ((ap = *++argv) != NULL) { 245 /* Return if "--" or not an option of any form. */ 246 if (ap[0] != '-') { 247 if (ap[0] != '+') 248 return; 249 } else if (ap[1] == '-') 250 return; 251 252 switch(*++ap) { 253 /* Old-style option. */ 254 case '0': case '1': case '2': case '3': case '4': 255 case '5': case '6': case '7': case '8': case '9': 256 257 /* Malloc space for dash, new option and argument. */ 258 len = strlen(*argv); 259 if ((start = p = malloc(len + 3)) == NULL) 260 err(1, "malloc"); 261 *p++ = '-'; 262 263 /* 264 * Go to the end of the option argument. Save off any 265 * trailing options (-3lf) and translate any trailing 266 * output style characters. 267 */ 268 t = *argv + len - 1; 269 if (*t == 'F' || *t == 'f' || *t == 'r') { 270 *p++ = *t; 271 *t-- = '\0'; 272 } 273 switch(*t) { 274 case 'b': 275 *p++ = 'b'; 276 *t = '\0'; 277 break; 278 case 'c': 279 *p++ = 'c'; 280 *t = '\0'; 281 break; 282 case 'l': 283 *t = '\0'; 284 /* FALLTHROUGH */ 285 case '0': case '1': case '2': case '3': case '4': 286 case '5': case '6': case '7': case '8': case '9': 287 *p++ = 'n'; 288 break; 289 default: 290 errx(1, "illegal option -- %s", *argv); 291 } 292 *p++ = *argv[0]; 293 (void)strcpy(p, ap); 294 *argv = start; 295 continue; 296 297 /* 298 * Options w/ arguments, skip the argument and continue 299 * with the next option. 300 */ 301 case 'b': 302 case 'c': 303 case 'n': 304 if (!ap[1]) 305 ++argv; 306 /* FALLTHROUGH */ 307 /* Options w/o arguments, continue with the next option. */ 308 case 'F': 309 case 'f': 310 case 'r': 311 continue; 312 313 /* Illegal option, return and let getopt handle it. */ 314 default: 315 return; 316 } 317 } 318 } 319 320 static void 321 usage(void) 322 { 323 (void)fprintf(stderr, 324 "usage: tail [-F | -f | -r] [-b # | -c # | -n #] [file ...]\n"); 325 exit(1); 326 } 327