2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
8 * Edward Sze-Tyan Wang.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
40 static const char copyright[] =
41 "@(#) Copyright (c) 1991, 1993\n\
42 The Regents of the University of California. All rights reserved.\n";
46 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
49 #include <sys/capsicum.h>
50 #include <sys/types.h>
53 #include <capsicum_helpers.h>
62 #include <libcasper.h>
63 #include <casper/cap_fileargs.h>
67 int Fflag, fflag, qflag, rflag, rval, no_files;
70 static file_info_t *files;
72 static void obsolete(char **);
73 static void usage(void);
75 static const struct option long_opts[] =
77 {"blocks", required_argument, NULL, 'b'},
78 {"bytes", required_argument, NULL, 'c'},
79 {"lines", required_argument, NULL, 'n'},
80 {NULL, no_argument, NULL, 0}
84 main(int argc, char *argv[])
97 * Tail's options are weird. First, -n10 is the same as -n-10, not
98 * -n+10. Second, the number options are 1 based and not offsets,
99 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
100 * number options for the -r option specify the number of things that
101 * get displayed, not the starting point in the file. The one major
102 * incompatibility in this version as compared to historical versions
103 * is that the 'r' option couldn't be modified by the -lbc options,
104 * i.e. it was always done in lines. This version treats -rc as a
105 * number of characters in reverse order. Finally, the default for
106 * -r is the entire file, not 10 lines.
108 #define ARG(units, forward, backward) { \
111 off = strtoll(optarg, &p, 10) * (units); \
113 errx(1, "illegal offset -- %s", optarg); \
114 switch(optarg[0]) { \
124 style = (backward); \
132 while ((ch = getopt_long(argc, argv, "+Fb:c:fn:qr", long_opts, NULL)) !=
135 case 'F': /* -F is superset of (and implies) -f */
139 ARG(512, FBYTES, RBYTES);
142 ARG(1, FBYTES, RBYTES);
148 ARG(1, FLINES, RLINES);
163 no_files = argc ? argc : 1;
165 cap_rights_init(&rights, CAP_FSTAT, CAP_FSTATFS, CAP_FCNTL,
168 cap_rights_set(&rights, CAP_EVENT);
169 if (caph_rights_limit(STDIN_FILENO, &rights) < 0 ||
170 caph_limit_stderr() < 0 || caph_limit_stdout() < 0)
171 err(1, "can't limit stdio rights");
173 fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN);
175 err(1, "unable to init casper");
177 caph_cache_catpages();
178 if (caph_enter_casper() < 0)
179 err(1, "unable to enter capability mode");
182 * If displaying in reverse, don't permit follow option, and convert
190 else if (style == FLINES)
195 * If style not specified, the default is the whole file for -r, and
196 * the last 10 lines if not -r.
198 if (style == NOTSET) {
208 if (*argv && fflag) {
209 files = (struct file_info *) malloc(no_files *
210 sizeof(struct file_info));
212 err(1, "Couldn't malloc space for file descriptors.");
214 for (file = files; (fn = *argv++); file++) {
215 file->file_name = strdup(fn);
216 if (! file->file_name)
217 errx(1, "Couldn't malloc space for file name.");
218 file->fp = fileargs_fopen(fa, file->file_name, "r");
219 if (file->fp == NULL ||
220 fstat(fileno(file->fp), &file->st)) {
221 if (file->fp != NULL) {
225 if (!Fflag || errno != ENOENT)
226 ierr(file->file_name);
229 follow(files, style, off);
230 for (i = 0, file = files; i < no_files; i++, file++) {
231 free(file->file_name);
235 for (first = 1; (fn = *argv++);) {
236 if ((fp = fileargs_fopen(fa, fn, "r")) == NULL ||
237 fstat(fileno(fp), &sb)) {
241 if (argc > 1 && !qflag) {
247 reverse(fp, fn, style, off, &sb);
249 forward(fp, fn, style, off, &sb);
254 if (fstat(fileno(stdin), &sb)) {
260 * Determine if input is a pipe. 4.4BSD will set the SOCKET
261 * bit in the st_mode field for pipes. Fix this then.
263 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
266 fflag = 0; /* POSIX.2 requires this. */
270 reverse(stdin, fn, style, off, &sb);
272 forward(stdin, fn, style, off, &sb);
279 * Convert the obsolete argument form into something that getopt can handle.
280 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
281 * the option argument for a -b, -c or -n option gets converted.
284 obsolete(char *argv[])
290 while ((ap = *++argv)) {
291 /* Return if "--" or not an option of any form. */
295 } else if (ap[1] == '-')
299 /* Old-style option. */
300 case '0': case '1': case '2': case '3': case '4':
301 case '5': case '6': case '7': case '8': case '9':
303 /* Malloc space for dash, new option and argument. */
305 if ((start = p = malloc(len + 3)) == NULL)
310 * Go to the end of the option argument. Save off any
311 * trailing options (-3lf) and translate any trailing
312 * output style characters.
315 if (*t == 'F' || *t == 'f' || *t == 'r') {
331 case '0': case '1': case '2': case '3': case '4':
332 case '5': case '6': case '7': case '8': case '9':
336 errx(1, "illegal option -- %s", *argv);
344 * Options w/ arguments, skip the argument and continue
345 * with the next option.
353 /* Options w/o arguments, continue with the next option. */
359 /* Illegal option, return and let getopt handle it. */
369 (void)fprintf(stderr,
370 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]"