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