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
37 static const char copyright[] =
38 "@(#) Copyright (c) 1991, 1993\n\
39 The Regents of the University of California. All rights reserved.\n";
43 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
46 #include <sys/capsicum.h>
47 #include <sys/types.h>
50 #include <capsicum_helpers.h>
61 #include <libcasper.h>
62 #include <casper/cap_fileargs.h>
66 int Fflag, fflag, qflag, rflag, rval, no_files, vflag;
69 static void obsolete(char **);
70 static void usage(void) __dead2;
72 static const struct option long_opts[] =
74 {"blocks", required_argument, NULL, 'b'},
75 {"bytes", required_argument, NULL, 'c'},
76 {"lines", required_argument, NULL, 'n'},
77 {"quiet", no_argument, NULL, 'q'},
78 {"silent", no_argument, NULL, 'q'},
79 {"verbose", no_argument, NULL, 'v'},
80 {NULL, no_argument, NULL, 0}
84 main(int argc, char *argv[])
92 file_info_t file, *filep, *files;
96 * Tail's options are weird. First, -n10 is the same as -n-10, not
97 * -n+10. Second, the number options are 1 based and not offsets,
98 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
99 * number options for the -r option specify the number of things that
100 * get displayed, not the starting point in the file. The one major
101 * incompatibility in this version as compared to historical versions
102 * is that the 'r' option couldn't be modified by the -lbc options,
103 * i.e. it was always done in lines. This version treats -rc as a
104 * number of characters in reverse order. Finally, the default for
105 * -r is the entire file, not 10 lines.
107 #define ARG(units, forward, backward) { \
110 if (expand_number(optarg, &off)) \
111 err(1, "illegal offset -- %s", optarg); \
112 if (off > INT64_MAX / units || off < INT64_MIN / 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:qrv", 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);
168 no_files = argc ? argc : 1;
170 cap_rights_init(&rights, CAP_FSTAT, CAP_FSTATFS, CAP_FCNTL,
173 cap_rights_set(&rights, CAP_EVENT);
174 if (caph_rights_limit(STDIN_FILENO, &rights) < 0 ||
175 caph_limit_stderr() < 0 || caph_limit_stdout() < 0)
176 err(1, "can't limit stdio rights");
178 fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN);
180 err(1, "unable to init casper");
182 caph_cache_catpages();
183 if (caph_enter_casper() < 0)
184 err(1, "unable to enter capability mode");
187 * If displaying in reverse, don't permit follow option, and convert
195 else if (style == FLINES)
200 * If style not specified, the default is the whole file for -r, and
201 * the last 10 lines if not -r.
203 if (style == NOTSET) {
213 if (*argv && fflag) {
214 files = malloc(no_files * sizeof(struct file_info));
216 err(1, "Couldn't malloc space for file descriptors.");
218 for (filep = files; (fn = *argv++); filep++) {
219 filep->file_name = fn;
220 filep->fp = fileargs_fopen(fa, filep->file_name, "r");
221 if (filep->fp == NULL ||
222 fstat(fileno(filep->fp), &filep->st)) {
223 if (filep->fp != NULL) {
227 if (!Fflag || errno != ENOENT)
228 ierr(filep->file_name);
231 follow(files, style, off);
234 for (first = 1; (fn = *argv++);) {
235 if ((fp = fileargs_fopen(fa, fn, "r")) == NULL ||
236 fstat(fileno(fp), &sb)) {
240 if (vflag || (qflag == 0 && argc > 1)) {
246 reverse(fp, fn, style, off, &sb);
248 forward(fp, fn, style, off, &sb);
253 if (fstat(fileno(stdin), &sb)) {
259 * Determine if input is a pipe. 4.4BSD will set the SOCKET
260 * bit in the st_mode field for pipes. Fix this then.
262 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
265 fflag = 0; /* POSIX.2 requires this. */
269 reverse(stdin, fn, style, off, &sb);
274 follow(&file, style, off);
276 forward(stdin, fn, style, off, &sb);
284 * Convert the obsolete argument form into something that getopt can handle.
285 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
286 * the option argument for a -b, -c or -n option gets converted.
289 obsolete(char *argv[])
295 while ((ap = *++argv)) {
296 /* Return if "--" or not an option of any form. */
300 } else if (ap[1] == '-')
304 /* Old-style option. */
305 case '0': case '1': case '2': case '3': case '4':
306 case '5': case '6': case '7': case '8': case '9':
308 /* Malloc space for dash, new option and argument. */
310 if ((start = p = malloc(len + 3)) == NULL)
315 * Go to the end of the option argument. Save off any
316 * trailing options (-3lf) and translate any trailing
317 * output style characters.
320 if (*t == 'F' || *t == 'f' || *t == 'r') {
336 case '0': case '1': case '2': case '3': case '4':
337 case '5': case '6': case '7': case '8': case '9':
341 errx(1, "illegal option -- %s", *argv);
349 * Options w/ arguments, skip the argument and continue
350 * with the next option.
358 /* Options w/o arguments, continue with the next option. */
364 /* Illegal option, return and let getopt handle it. */
374 (void)fprintf(stderr,
375 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]"