1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Edward Sze-Tyan Wang.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
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.
21 *
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
32 * SUCH DAMAGE.
33 */
34
35
36 #ifndef lint
37 static const char copyright[] =
38 "@(#) Copyright (c) 1991, 1993\n\
39 The Regents of the University of California. All rights reserved.\n";
40 #endif
41
42 #ifndef lint
43 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
44 #endif
45
46 #include <sys/capsicum.h>
47 #include <sys/types.h>
48 #include <sys/stat.h>
49
50 #include <capsicum_helpers.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <getopt.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58
59 #include <libutil.h>
60
61 #include <libcasper.h>
62 #include <casper/cap_fileargs.h>
63
64 #include "extern.h"
65
66 int Fflag, fflag, qflag, rflag, rval, no_files, vflag;
67 fileargs_t *fa;
68
69 static void obsolete(char **);
70 static void usage(void) __dead2;
71
72 static const struct option long_opts[] =
73 {
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}
81 };
82
83 int
main(int argc,char * argv[])84 main(int argc, char *argv[])
85 {
86 struct stat sb;
87 const char *fn;
88 FILE *fp;
89 off_t off;
90 enum STYLE style;
91 int ch, first;
92 file_info_t file, *filep, *files;
93 cap_rights_t rights;
94
95 /*
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.
106 */
107 #define ARG(units, forward, backward) { \
108 if (style) \
109 usage(); \
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]) { \
115 case '+': \
116 if (off) \
117 off -= (units); \
118 style = (forward); \
119 break; \
120 case '-': \
121 off = -off; \
122 /* FALLTHROUGH */ \
123 default: \
124 style = (backward); \
125 break; \
126 } \
127 }
128
129 obsolete(argv);
130 style = NOTSET;
131 off = 0;
132 while ((ch = getopt_long(argc, argv, "+Fb:c:fn:qrv", long_opts, NULL)) !=
133 -1)
134 switch(ch) {
135 case 'F': /* -F is superset of (and implies) -f */
136 Fflag = fflag = 1;
137 break;
138 case 'b':
139 ARG(512, FBYTES, RBYTES);
140 break;
141 case 'c':
142 ARG(1, FBYTES, RBYTES);
143 break;
144 case 'f':
145 fflag = 1;
146 break;
147 case 'n':
148 ARG(1, FLINES, RLINES);
149 break;
150 case 'q':
151 qflag = 1;
152 vflag = 0;
153 break;
154 case 'r':
155 rflag = 1;
156 break;
157 case 'v':
158 vflag = 1;
159 qflag = 0;
160 break;
161 case '?':
162 default:
163 usage();
164 }
165 argc -= optind;
166 argv += optind;
167
168 no_files = argc ? argc : 1;
169
170 cap_rights_init(&rights, CAP_FSTAT, CAP_FSTATFS, CAP_FCNTL,
171 CAP_MMAP_R);
172 if (fflag)
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, "unable to limit stdio rights");
177
178 fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN);
179 if (fa == NULL)
180 err(1, "unable to init casper");
181
182 caph_cache_catpages();
183 if (caph_enter_casper() < 0)
184 err(1, "unable to enter capability mode");
185
186 /*
187 * If displaying in reverse, don't permit follow option, and convert
188 * style values.
189 */
190 if (rflag) {
191 if (fflag)
192 usage();
193 if (style == FBYTES)
194 style = RBYTES;
195 else if (style == FLINES)
196 style = RLINES;
197 }
198
199 /*
200 * If style not specified, the default is the whole file for -r, and
201 * the last 10 lines if not -r.
202 */
203 if (style == NOTSET) {
204 if (rflag) {
205 off = 0;
206 style = REVERSE;
207 } else {
208 off = 10;
209 style = RLINES;
210 }
211 }
212
213 if (*argv && fflag) {
214 files = malloc(no_files * sizeof(struct file_info));
215 if (files == NULL)
216 err(1, "failed to allocate memory for file descriptors");
217
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) {
224 fclose(filep->fp);
225 filep->fp = NULL;
226 }
227 if (!Fflag || errno != ENOENT)
228 ierr(filep->file_name);
229 }
230 }
231 follow(files, style, off);
232 free(files);
233 } else if (*argv) {
234 for (first = 1; (fn = *argv++);) {
235 if ((fp = fileargs_fopen(fa, fn, "r")) == NULL ||
236 fstat(fileno(fp), &sb)) {
237 ierr(fn);
238 continue;
239 }
240 if (vflag || (qflag == 0 && argc > 1)) {
241 printfn(fn, !first);
242 first = 0;
243 }
244
245 if (rflag)
246 reverse(fp, fn, style, off, &sb);
247 else
248 forward(fp, fn, style, off, &sb);
249 }
250 } else {
251 fn = "stdin";
252
253 if (fstat(fileno(stdin), &sb)) {
254 ierr(fn);
255 exit(1);
256 }
257
258 /*
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.
261 */
262 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
263 errno == ESPIPE) {
264 errno = 0;
265 fflag = 0; /* POSIX.2 requires this. */
266 }
267
268 if (rflag) {
269 reverse(stdin, fn, style, off, &sb);
270 } else if (fflag) {
271 file.file_name = fn;
272 file.fp = stdin;
273 file.st = sb;
274 follow(&file, style, off);
275 } else {
276 forward(stdin, fn, style, off, &sb);
277 }
278 }
279 fileargs_free(fa);
280 exit(rval);
281 }
282
283 /*
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.
287 */
288 static void
obsolete(char * argv[])289 obsolete(char *argv[])
290 {
291 char *ap, *p, *t;
292 size_t len;
293 char *start;
294
295 while ((ap = *++argv)) {
296 /* Return if "--" or not an option of any form. */
297 if (ap[0] != '-') {
298 if (ap[0] != '+')
299 return;
300 } else if (ap[1] == '-')
301 return;
302
303 switch(*++ap) {
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':
307
308 /* Malloc space for dash, new option and argument. */
309 len = strlen(*argv);
310 if ((start = p = malloc(len + 3)) == NULL)
311 err(1, "failed to allocate memory");
312 *p++ = '-';
313
314 /*
315 * Go to the end of the option argument. Save off any
316 * trailing options (-3lf) and translate any trailing
317 * output style characters.
318 */
319 t = *argv + len - 1;
320 if (*t == 'F' || *t == 'f' || *t == 'r') {
321 *p++ = *t;
322 *t-- = '\0';
323 }
324 switch(*t) {
325 case 'b':
326 *p++ = 'b';
327 *t = '\0';
328 break;
329 case 'c':
330 *p++ = 'c';
331 *t = '\0';
332 break;
333 case 'l':
334 *t = '\0';
335 /* FALLTHROUGH */
336 case '0': case '1': case '2': case '3': case '4':
337 case '5': case '6': case '7': case '8': case '9':
338 *p++ = 'n';
339 break;
340 default:
341 errx(1, "illegal option -- %s", *argv);
342 }
343 *p++ = *argv[0];
344 (void)strcpy(p, ap);
345 *argv = start;
346 continue;
347
348 /*
349 * Options w/ arguments, skip the argument and continue
350 * with the next option.
351 */
352 case 'b':
353 case 'c':
354 case 'n':
355 if (!ap[1])
356 ++argv;
357 /* FALLTHROUGH */
358 /* Options w/o arguments, continue with the next option. */
359 case 'F':
360 case 'f':
361 case 'r':
362 continue;
363
364 /* Illegal option, return and let getopt handle it. */
365 default:
366 return;
367 }
368 }
369 }
370
371 static void
usage(void)372 usage(void)
373 {
374 (void)fprintf(stderr,
375 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]"
376 " [file ...]\n");
377 exit(1);
378 }
379