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 */ 36 37 #include <sys/types.h> 38 #include <sys/stat.h> 39 #include <errno.h> 40 #include <unistd.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <err.h> 45 #include "extern.h" 46 47 int Fflag, fflag, qflag, rflag, rval, no_files; 48 const char *fname; 49 50 file_info_t *files; 51 52 static void obsolete(char **); 53 static void usage(void); 54 static void getarg(int, enum STYLE, enum STYLE, enum STYLE *, int *, off_t *); 55 56 int 57 main(int argc, char **argv) 58 { 59 struct stat sb; 60 FILE *fp; 61 off_t off = 0; 62 enum STYLE style; 63 int style_set; 64 int i, ch; 65 file_info_t *file; 66 67 obsolete(argv); 68 style_set = 0; 69 while ((ch = getopt(argc, argv, "Fb:c:fn:qr")) != -1) 70 switch(ch) { 71 case 'F': /* -F is superset of (and implies) -f */ 72 Fflag = fflag = 1; 73 break; 74 case 'b': 75 getarg(512, FBYTES, RBYTES, &style, &style_set, &off); 76 break; 77 case 'c': 78 getarg(1, FBYTES, RBYTES, &style, &style_set, &off); 79 break; 80 case 'f': 81 fflag = 1; 82 break; 83 case 'n': 84 getarg(1, FLINES, RLINES, &style, &style_set, &off); 85 break; 86 case 'q': 87 qflag = 1; 88 break; 89 case 'r': 90 rflag = 1; 91 break; 92 case '?': 93 default: 94 usage(); 95 } 96 argc -= optind; 97 argv += optind; 98 99 no_files = argc ? argc : 1; 100 101 /* 102 * If displaying in reverse, don't permit follow option, and convert 103 * style values. 104 */ 105 if (rflag) { 106 if (fflag) 107 usage(); 108 if (style == FBYTES) 109 style = RBYTES; 110 else if (style == FLINES) 111 style = RLINES; 112 } 113 114 /* 115 * If style not specified, the default is the whole file for -r, and 116 * the last 10 lines if not -r. 117 */ 118 if (!style_set) { 119 if (rflag) { 120 off = 0; 121 style = REVERSE; 122 } else { 123 off = 10; 124 style = RLINES; 125 } 126 } 127 128 if (*argv && fflag) { 129 files = malloc(no_files * sizeof(struct file_info)); 130 if (files == NULL) 131 err(1, "Couldn't malloc space for files descriptors."); 132 133 for (file = files; (fname = *argv++) != NULL; file++) { 134 file->file_name = strdup(fname); 135 if (! file->file_name) 136 errx(1, "Couldn't alloc space for file name."); 137 file->fp = fopen(file->file_name, "r"); 138 if (file->fp == NULL || 139 fstat(fileno(file->fp), &file->st) == -1) { 140 file->fp = NULL; 141 ierr(); 142 } 143 } 144 follow(files, style, off); 145 for (i = 0, file = files; i < no_files; i++, file++) 146 free(file->file_name); 147 free(files); 148 } else if (*argv) { 149 for (i = 0; (fname = *argv++) != NULL; ++i) { 150 if ((fp = fopen(fname, "r")) == NULL || 151 fstat(fileno(fp), &sb)) { 152 ierr(); 153 continue; 154 } 155 if (argc > 1) { 156 showfilename(i, fname); 157 (void)fflush(stdout); 158 } 159 160 if (rflag) 161 reverse(fp, style, off, &sb); 162 else 163 forward(fp, style, off, &sb); 164 (void)fclose(fp); 165 } 166 } else { 167 fname = "stdin"; 168 169 if (fstat(fileno(stdin), &sb)) { 170 ierr(); 171 exit(1); 172 } 173 174 /* 175 * Determine if input is a pipe. 4.4BSD will set the SOCKET 176 * bit in the st_mode field for pipes. Fix this then. 177 */ 178 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 && 179 errno == ESPIPE) { 180 errno = 0; 181 fflag = 0; /* POSIX.2 requires this. */ 182 } 183 184 if (rflag) 185 reverse(stdin, style, off, &sb); 186 else 187 forward(stdin, style, off, &sb); 188 } 189 exit(rval); 190 } 191 192 /* 193 * Tail's options are weird. First, -n10 is the same as -n-10, not 194 * -n+10. Second, the number options are 1 based and not offsets, 195 * so -n+1 is the first line, and -c-1 is the last byte. Third, the 196 * number options for the -r option specify the number of things that 197 * get displayed, not the starting point in the file. The one major 198 * incompatibility in this version as compared to historical versions 199 * is that the 'r' option couldn't be modified by the -lbc options, 200 * i.e. it was always done in lines. This version treats -rc as a 201 * number of characters in reverse order. Finally, the default for 202 * -r is the entire file, not 10 lines. 203 */ 204 static void 205 getarg(int units, enum STYLE forward_style, enum STYLE backward_style, 206 enum STYLE *style, int *style_set, off_t *off) 207 { 208 char *p; 209 210 if (*style_set) 211 usage(); 212 213 *off = strtoll(optarg, &p, 10) * units; 214 if (*p != '\0') 215 errx(1, "illegal offset -- %s", optarg); 216 switch (optarg[0]) { 217 case '+': 218 if (*off != 0) 219 *off -= (units); 220 *style = forward_style; 221 break; 222 case '-': 223 *off = -*off; 224 /* FALLTHROUGH */ 225 default: 226 *style = backward_style; 227 break; 228 } 229 230 *style_set = 1; 231 } 232 233 /* 234 * Convert the obsolete argument form into something that getopt can handle. 235 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't 236 * the option argument for a -b, -c or -n option gets converted. 237 */ 238 static void 239 obsolete(char **argv) 240 { 241 char *ap, *p, *t; 242 size_t len; 243 char *start; 244 245 while ((ap = *++argv) != NULL) { 246 /* Return if "--" or not an option of any form. */ 247 if (ap[0] != '-') { 248 if (ap[0] != '+') 249 return; 250 } else if (ap[1] == '-') 251 return; 252 253 switch(*++ap) { 254 /* Old-style option. */ 255 case '0': case '1': case '2': case '3': case '4': 256 case '5': case '6': case '7': case '8': case '9': 257 258 /* Malloc space for dash, new option and argument. */ 259 len = strlen(*argv); 260 if ((start = p = malloc(len + 3)) == NULL) 261 err(1, "malloc"); 262 *p++ = '-'; 263 264 /* 265 * Go to the end of the option argument. Save off any 266 * trailing options (-3lf) and translate any trailing 267 * output style characters. 268 */ 269 t = *argv + len - 1; 270 if (*t == 'F' || *t == 'f' || *t == 'r') { 271 *p++ = *t; 272 *t-- = '\0'; 273 } 274 switch(*t) { 275 case 'b': 276 *p++ = 'b'; 277 *t = '\0'; 278 break; 279 case 'c': 280 *p++ = 'c'; 281 *t = '\0'; 282 break; 283 case 'l': 284 *t = '\0'; 285 /* FALLTHROUGH */ 286 case '0': case '1': case '2': case '3': case '4': 287 case '5': case '6': case '7': case '8': case '9': 288 *p++ = 'n'; 289 break; 290 default: 291 errx(1, "illegal option -- %s", *argv); 292 } 293 *p++ = *argv[0]; 294 (void)strcpy(p, ap); 295 *argv = start; 296 continue; 297 298 /* 299 * Options w/ arguments, skip the argument and continue 300 * with the next option. 301 */ 302 case 'b': 303 case 'c': 304 case 'n': 305 if (!ap[1]) 306 ++argv; 307 /* FALLTHROUGH */ 308 /* Options w/o arguments, continue with the next option. */ 309 case 'F': 310 case 'f': 311 case 'r': 312 continue; 313 314 /* Illegal option, return and let getopt handle it. */ 315 default: 316 return; 317 } 318 } 319 } 320 321 static void 322 usage(void) 323 { 324 (void)fprintf(stderr, 325 "usage: tail [-F | -f | -r] [-b # | -c # | -n #] [file ...]\n"); 326 exit(1); 327 } 328