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 * @(#)tail.c 8.1 (Berkeley) 6/6/93
33 * $FreeBSD: src/usr.bin/tail/tail.c,v 1.6.2.2 2001/12/19 20:29:31 iedowse Exp $
34 */
35
36 #include <sys/types.h>
37 #include <sys/stat.h>
38 #include <errno.h>
39 #include <unistd.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <err.h>
44 #include "extern.h"
45
46 int Fflag, fflag, qflag, rflag, vflag, rval, no_files;
47 const char *fname;
48
49 #ifndef BOOTSTRAPPING
50 file_info_t *files;
51 #endif
52
53 static void obsolete(char **);
54 static void usage(void) __dead2;
55 static void getarg(int, enum STYLE, enum STYLE, enum STYLE *, int *, off_t *);
56
57 int
main(int argc,char ** argv)58 main(int argc, char **argv)
59 {
60 const char *optstring;
61 struct stat sb;
62 FILE *fp;
63 off_t off = 0;
64 enum STYLE style;
65 int style_set;
66 int i, ch;
67 #ifndef BOOTSTRAPPING
68 file_info_t *file;
69 #endif
70
71 if (strcmp(getprogname(), "tac") == 0) {
72 optstring = "";
73 qflag = 1;
74 rflag = 1;
75 vflag = 0;
76 } else {
77 /* tail */
78 optstring = "Fb:c:fn:qrv";
79 }
80
81 obsolete(argv);
82 style_set = 0;
83 while ((ch = getopt(argc, argv, optstring)) != -1) {
84 switch(ch) {
85 case 'F': /* -F is superset of (and implies) -f */
86 #ifndef BOOTSTRAPPING
87 Fflag = fflag = 1;
88 #endif
89 break;
90 case 'b':
91 getarg(512, FBYTES, RBYTES, &style, &style_set, &off);
92 break;
93 case 'c':
94 getarg(1, FBYTES, RBYTES, &style, &style_set, &off);
95 break;
96 case 'f':
97 #ifndef BOOTSTRAPPING
98 fflag = 1;
99 #endif
100 break;
101 case 'n':
102 getarg(1, FLINES, RLINES, &style, &style_set, &off);
103 break;
104 case 'q':
105 qflag = 1;
106 vflag = 0;
107 break;
108 case 'r':
109 rflag = 1;
110 break;
111 case 'v':
112 vflag = 1;
113 qflag = 0;
114 break;
115 default:
116 usage();
117 }
118 }
119 argc -= optind;
120 argv += optind;
121
122 no_files = argc ? argc : 1;
123
124 /*
125 * If displaying in reverse, don't permit follow option, and convert
126 * style values.
127 */
128 if (rflag) {
129 if (fflag)
130 usage();
131 if (style == FBYTES)
132 style = RBYTES;
133 else if (style == FLINES)
134 style = RLINES;
135 }
136
137 /*
138 * If style not specified, the default is the whole file for -r, and
139 * the last 10 lines if not -r.
140 */
141 if (!style_set) {
142 if (rflag) {
143 off = 0;
144 style = REVERSE;
145 } else {
146 off = 10;
147 style = RLINES;
148 }
149 }
150
151 #ifndef BOOTSTRAPPING
152 if (*argv && fflag) {
153 files = malloc(no_files * sizeof(struct file_info));
154 if (files == NULL)
155 err(1, "Couldn't malloc space for files descriptors.");
156
157 for (file = files; (fname = *argv++) != NULL; file++) {
158 file->file_name = strdup(fname);
159 if (! file->file_name)
160 errx(1, "Couldn't alloc space for file name.");
161 file->fp = fopen(file->file_name, "r");
162 if (file->fp == NULL ||
163 fstat(fileno(file->fp), &file->st) == -1) {
164 file->fp = NULL;
165 ierr();
166 }
167 }
168 follow(files, style, off);
169 for (i = 0, file = files; i < no_files; i++, file++)
170 free(file->file_name);
171 free(files);
172 } else
173 #endif
174 if (*argv) {
175 for (i = 0; (fname = *argv++) != NULL; ++i) {
176 if ((fp = fopen(fname, "r")) == NULL ||
177 fstat(fileno(fp), &sb)) {
178 ierr();
179 continue;
180 }
181 if (vflag || argc > 1) {
182 showfilename(i, fname);
183 (void)fflush(stdout);
184 }
185
186 if (rflag)
187 reverse(fp, style, off, &sb);
188 else
189 forward(fp, style, off, &sb);
190 (void)fclose(fp);
191 }
192 } else {
193 fname = "stdin";
194
195 if (fstat(fileno(stdin), &sb)) {
196 ierr();
197 exit(1);
198 }
199
200 /*
201 * Determine if input is a pipe. 4.4BSD will set the SOCKET
202 * bit in the st_mode field for pipes. Fix this then.
203 */
204 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
205 errno == ESPIPE) {
206 errno = 0;
207 fflag = 0; /* POSIX.2 requires this. */
208 }
209
210 if (rflag)
211 reverse(stdin, style, off, &sb);
212 else
213 forward(stdin, style, off, &sb);
214 }
215 exit(rval);
216 }
217
218 /*
219 * Tail's options are weird. First, -n10 is the same as -n-10, not
220 * -n+10. Second, the number options are 1 based and not offsets,
221 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
222 * number options for the -r option specify the number of things that
223 * get displayed, not the starting point in the file. The one major
224 * incompatibility in this version as compared to historical versions
225 * is that the 'r' option couldn't be modified by the -lbc options,
226 * i.e. it was always done in lines. This version treats -rc as a
227 * number of characters in reverse order. Finally, the default for
228 * -r is the entire file, not 10 lines.
229 */
230 static void
getarg(int units,enum STYLE forward_style,enum STYLE backward_style,enum STYLE * style,int * style_set,off_t * off)231 getarg(int units, enum STYLE forward_style, enum STYLE backward_style,
232 enum STYLE *style, int *style_set, off_t *off)
233 {
234 char *p;
235
236 if (*style_set)
237 usage();
238
239 *off = strtoll(optarg, &p, 10) * units;
240 if (*p != '\0')
241 errx(1, "illegal offset -- %s", optarg);
242 switch (optarg[0]) {
243 case '+':
244 if (*off != 0)
245 *off -= (units);
246 *style = forward_style;
247 break;
248 case '-':
249 *off = -*off;
250 /* FALLTHROUGH */
251 default:
252 *style = backward_style;
253 break;
254 }
255
256 *style_set = 1;
257 }
258
259 /*
260 * Convert the obsolete argument form into something that getopt can handle.
261 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
262 * the option argument for a -b, -c or -n option gets converted.
263 */
264 static void
obsolete(char ** argv)265 obsolete(char **argv)
266 {
267 char *ap, *p, *t;
268 size_t len;
269 char *start;
270
271 while ((ap = *++argv) != NULL) {
272 /* Return if "--" or not an option of any form. */
273 if (ap[0] != '-') {
274 if (ap[0] != '+')
275 return;
276 } else if (ap[1] == '-')
277 return;
278
279 switch(*++ap) {
280 /* Old-style option. */
281 case '0': case '1': case '2': case '3': case '4':
282 case '5': case '6': case '7': case '8': case '9':
283
284 /* Malloc space for dash, new option and argument. */
285 len = strlen(*argv);
286 if ((start = p = malloc(len + 3)) == NULL)
287 err(1, "malloc");
288 *p++ = '-';
289
290 /*
291 * Go to the end of the option argument. Save off any
292 * trailing options (-3lf) and translate any trailing
293 * output style characters.
294 */
295 t = *argv + len - 1;
296 if (*t == 'F' || *t == 'f' || *t == 'r') {
297 *p++ = *t;
298 *t-- = '\0';
299 }
300 switch(*t) {
301 case 'b':
302 *p++ = 'b';
303 *t = '\0';
304 break;
305 case 'c':
306 *p++ = 'c';
307 *t = '\0';
308 break;
309 case 'l':
310 *t = '\0';
311 /* FALLTHROUGH */
312 case '0': case '1': case '2': case '3': case '4':
313 case '5': case '6': case '7': case '8': case '9':
314 *p++ = 'n';
315 break;
316 default:
317 errx(1, "illegal option -- %s", *argv);
318 }
319 *p++ = *argv[0];
320 (void)strcpy(p, ap);
321 *argv = start;
322 continue;
323
324 /*
325 * Options w/ arguments, skip the argument and continue
326 * with the next option.
327 */
328 case 'b':
329 case 'c':
330 case 'n':
331 if (!ap[1])
332 ++argv;
333 /* FALLTHROUGH */
334 /* Options w/o arguments, continue with the next option. */
335 case 'F':
336 case 'f':
337 case 'r':
338 continue;
339
340 /* Illegal option, return and let getopt handle it. */
341 default:
342 return;
343 }
344 }
345 }
346
347 static void __dead2
usage(void)348 usage(void)
349 {
350 if (strcmp(getprogname(), "tac") == 0) {
351 fprintf(stderr, "usage: tac [file ...]\n");
352 } else {
353 fprintf(stderr,
354 "usage: tail [-F | -f | -r] [-q | -v] "
355 "[-b # | -c # | -n #] [file ...]\n");
356 }
357 exit(1);
358 }
359