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 #include <sys/capsicum.h>
37 #include <sys/types.h>
38 #include <sys/stat.h>
39
40 #include <capsicum_helpers.h>
41 #include <err.h>
42 #include <errno.h>
43 #include <getopt.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <unistd.h>
48
49 #include <libutil.h>
50
51 #include <libcasper.h>
52 #include <casper/cap_fileargs.h>
53
54 #include "extern.h"
55
56 int Fflag, fflag, qflag, rflag, rval, no_files, vflag;
57 fileargs_t *fa;
58
59 static void obsolete(char **);
60 static void usage(void) __dead2;
61
62 static const struct option long_opts[] =
63 {
64 {"blocks", required_argument, NULL, 'b'},
65 {"bytes", required_argument, NULL, 'c'},
66 {"lines", required_argument, NULL, 'n'},
67 {"quiet", no_argument, NULL, 'q'},
68 {"silent", no_argument, NULL, 'q'},
69 {"verbose", no_argument, NULL, 'v'},
70 {NULL, no_argument, NULL, 0}
71 };
72
73 int
main(int argc,char * argv[])74 main(int argc, char *argv[])
75 {
76 struct stat sb;
77 const char *fn;
78 FILE *fp;
79 off_t off;
80 enum STYLE style;
81 int ch, first;
82 file_info_t file, *filep, *files;
83 cap_rights_t rights;
84
85 /*
86 * Tail's options are weird. First, -n10 is the same as -n-10, not
87 * -n+10. Second, the number options are 1 based and not offsets,
88 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
89 * number options for the -r option specify the number of things that
90 * get displayed, not the starting point in the file. The one major
91 * incompatibility in this version as compared to historical versions
92 * is that the 'r' option couldn't be modified by the -lbc options,
93 * i.e. it was always done in lines. This version treats -rc as a
94 * number of characters in reverse order. Finally, the default for
95 * -r is the entire file, not 10 lines.
96 */
97 #define ARG(units, forward, backward) { \
98 int64_t num; \
99 if (style) \
100 usage(); \
101 if (expand_number(optarg, &num)) \
102 err(1, "illegal offset -- %s", optarg); \
103 if (num > INT64_MAX / units || num < INT64_MIN / units) \
104 errx(1, "illegal offset -- %s", optarg); \
105 off = num * units; \
106 switch (optarg[0]) { \
107 case '+': \
108 if (off != 0) \
109 off -= (units); \
110 style = (forward); \
111 break; \
112 case '-': \
113 off = -off; \
114 /* FALLTHROUGH */ \
115 default: \
116 style = (backward); \
117 break; \
118 } \
119 }
120
121 obsolete(argv);
122 style = NOTSET;
123 off = 0;
124 while ((ch = getopt_long(argc, argv, "+Fb:c:fn:qrv", long_opts, NULL)) !=
125 -1)
126 switch (ch) {
127 case 'F': /* -F is superset of (and implies) -f */
128 Fflag = fflag = 1;
129 break;
130 case 'b':
131 ARG(512, FBYTES, RBYTES);
132 break;
133 case 'c':
134 ARG(1, FBYTES, RBYTES);
135 break;
136 case 'f':
137 fflag = 1;
138 break;
139 case 'n':
140 ARG(1, FLINES, RLINES);
141 break;
142 case 'q':
143 qflag = 1;
144 vflag = 0;
145 break;
146 case 'r':
147 rflag = 1;
148 break;
149 case 'v':
150 vflag = 1;
151 qflag = 0;
152 break;
153 case '?':
154 default:
155 usage();
156 }
157 argc -= optind;
158 argv += optind;
159
160 no_files = argc ? argc : 1;
161
162 cap_rights_init(&rights, CAP_FSTAT, CAP_FSTATFS, CAP_FCNTL,
163 CAP_MMAP_R);
164 if (fflag)
165 cap_rights_set(&rights, CAP_EVENT);
166 if (caph_rights_limit(STDIN_FILENO, &rights) < 0 ||
167 caph_limit_stderr() < 0 || caph_limit_stdout() < 0)
168 err(1, "unable to limit stdio rights");
169
170 fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN);
171 if (fa == NULL)
172 err(1, "unable to init casper");
173
174 caph_cache_catpages();
175 if (caph_enter_casper() < 0)
176 err(1, "unable to enter capability mode");
177
178 /*
179 * If displaying in reverse, don't permit follow option, and convert
180 * style values.
181 */
182 if (rflag) {
183 if (fflag)
184 usage();
185 if (style == FBYTES)
186 style = RBYTES;
187 else if (style == FLINES)
188 style = RLINES;
189 }
190
191 /*
192 * If style not specified, the default is the whole file for -r, and
193 * the last 10 lines if not -r.
194 */
195 if (style == NOTSET) {
196 if (rflag) {
197 off = 0;
198 style = REVERSE;
199 } else {
200 off = 10;
201 style = RLINES;
202 }
203 }
204
205 if (*argv && fflag) {
206 files = malloc(no_files * sizeof(struct file_info));
207 if (files == NULL)
208 err(1, "failed to allocate memory for file descriptors");
209
210 for (filep = files; (fn = *argv++); filep++) {
211 filep->file_name = fn;
212 filep->fp = fileargs_fopen(fa, filep->file_name, "r");
213 if (filep->fp == NULL ||
214 fstat(fileno(filep->fp), &filep->st)) {
215 if (filep->fp != NULL) {
216 fclose(filep->fp);
217 filep->fp = NULL;
218 }
219 if (!Fflag || errno != ENOENT)
220 ierr(filep->file_name);
221 }
222 }
223 follow(files, style, off);
224 free(files);
225 } else if (*argv) {
226 for (first = 1; (fn = *argv++);) {
227 if ((fp = fileargs_fopen(fa, fn, "r")) == NULL ||
228 fstat(fileno(fp), &sb)) {
229 ierr(fn);
230 continue;
231 }
232 if (vflag || (qflag == 0 && argc > 1)) {
233 printfn(fn, !first);
234 first = 0;
235 }
236
237 if (rflag)
238 reverse(fp, fn, style, off, &sb);
239 else
240 forward(fp, fn, style, off, &sb);
241 }
242 } else {
243 fn = "stdin";
244
245 if (fstat(fileno(stdin), &sb)) {
246 ierr(fn);
247 exit(1);
248 }
249
250 /*
251 * Determine if input is a pipe. 4.4BSD will set the SOCKET
252 * bit in the st_mode field for pipes. Fix this then.
253 */
254 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
255 errno == ESPIPE) {
256 errno = 0;
257 fflag = 0; /* POSIX.2 requires this. */
258 }
259
260 if (rflag) {
261 reverse(stdin, fn, style, off, &sb);
262 } else if (fflag) {
263 file.file_name = fn;
264 file.fp = stdin;
265 file.st = sb;
266 follow(&file, style, off);
267 } else {
268 forward(stdin, fn, style, off, &sb);
269 }
270 }
271 fileargs_free(fa);
272 exit(rval);
273 }
274
275 /*
276 * Convert the obsolete argument form into something that getopt can handle.
277 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
278 * the option argument for a -b, -c or -n option gets converted.
279 */
280 static void
obsolete(char * argv[])281 obsolete(char *argv[])
282 {
283 char *ap, *p, *t;
284 size_t len;
285 char *start;
286
287 while ((ap = *++argv)) {
288 /* Return if "--" or not an option of any form. */
289 if (ap[0] != '-') {
290 if (ap[0] != '+')
291 return;
292 } else if (ap[1] == '-')
293 return;
294
295 switch(*++ap) {
296 /* Old-style option. */
297 case '0': case '1': case '2': case '3': case '4':
298 case '5': case '6': case '7': case '8': case '9':
299
300 /* Malloc space for dash, new option and argument. */
301 len = strlen(*argv);
302 if ((start = p = malloc(len + 3)) == NULL)
303 err(1, "failed to allocate memory");
304 *p++ = '-';
305
306 /*
307 * Go to the end of the option argument. Save off any
308 * trailing options (-3lf) and translate any trailing
309 * output style characters.
310 */
311 t = *argv + len - 1;
312 if (*t == 'F' || *t == 'f' || *t == 'r') {
313 *p++ = *t;
314 *t-- = '\0';
315 }
316 switch(*t) {
317 case 'b':
318 *p++ = 'b';
319 *t = '\0';
320 break;
321 case 'c':
322 *p++ = 'c';
323 *t = '\0';
324 break;
325 case 'l':
326 *t = '\0';
327 /* FALLTHROUGH */
328 case '0': case '1': case '2': case '3': case '4':
329 case '5': case '6': case '7': case '8': case '9':
330 *p++ = 'n';
331 break;
332 default:
333 errx(1, "illegal option -- %s", *argv);
334 }
335 *p++ = *argv[0];
336 (void)strcpy(p, ap);
337 *argv = start;
338 continue;
339
340 /*
341 * Options w/ arguments, skip the argument and continue
342 * with the next option.
343 */
344 case 'b':
345 case 'c':
346 case 'n':
347 if (!ap[1])
348 ++argv;
349 /* FALLTHROUGH */
350 /* Options w/o arguments, continue with the next option. */
351 case 'F':
352 case 'f':
353 case 'r':
354 continue;
355
356 /* Illegal option, return and let getopt handle it. */
357 default:
358 return;
359 }
360 }
361 }
362
363 static void
usage(void)364 usage(void)
365 {
366 (void)fprintf(stderr,
367 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]"
368 " [file ...]\n");
369 exit(1);
370 }
371