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 if (style) \
99 usage(); \
100 if (expand_number(optarg, &off)) \
101 err(1, "illegal offset -- %s", optarg); \
102 if (off > INT64_MAX / units || off < INT64_MIN / units ) \
103 errx(1, "illegal offset -- %s", optarg); \
104 switch(optarg[0]) { \
105 case '+': \
106 if (off) \
107 off -= (units); \
108 style = (forward); \
109 break; \
110 case '-': \
111 off = -off; \
112 /* FALLTHROUGH */ \
113 default: \
114 style = (backward); \
115 break; \
116 } \
117 }
118
119 obsolete(argv);
120 style = NOTSET;
121 off = 0;
122 while ((ch = getopt_long(argc, argv, "+Fb:c:fn:qrv", long_opts, NULL)) !=
123 -1)
124 switch(ch) {
125 case 'F': /* -F is superset of (and implies) -f */
126 Fflag = fflag = 1;
127 break;
128 case 'b':
129 ARG(512, FBYTES, RBYTES);
130 break;
131 case 'c':
132 ARG(1, FBYTES, RBYTES);
133 break;
134 case 'f':
135 fflag = 1;
136 break;
137 case 'n':
138 ARG(1, FLINES, RLINES);
139 break;
140 case 'q':
141 qflag = 1;
142 vflag = 0;
143 break;
144 case 'r':
145 rflag = 1;
146 break;
147 case 'v':
148 vflag = 1;
149 qflag = 0;
150 break;
151 case '?':
152 default:
153 usage();
154 }
155 argc -= optind;
156 argv += optind;
157
158 no_files = argc ? argc : 1;
159
160 cap_rights_init(&rights, CAP_FSTAT, CAP_FSTATFS, CAP_FCNTL,
161 CAP_MMAP_R);
162 if (fflag)
163 cap_rights_set(&rights, CAP_EVENT);
164 if (caph_rights_limit(STDIN_FILENO, &rights) < 0 ||
165 caph_limit_stderr() < 0 || caph_limit_stdout() < 0)
166 err(1, "unable to limit stdio rights");
167
168 fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN);
169 if (fa == NULL)
170 err(1, "unable to init casper");
171
172 caph_cache_catpages();
173 if (caph_enter_casper() < 0)
174 err(1, "unable to enter capability mode");
175
176 /*
177 * If displaying in reverse, don't permit follow option, and convert
178 * style values.
179 */
180 if (rflag) {
181 if (fflag)
182 usage();
183 if (style == FBYTES)
184 style = RBYTES;
185 else if (style == FLINES)
186 style = RLINES;
187 }
188
189 /*
190 * If style not specified, the default is the whole file for -r, and
191 * the last 10 lines if not -r.
192 */
193 if (style == NOTSET) {
194 if (rflag) {
195 off = 0;
196 style = REVERSE;
197 } else {
198 off = 10;
199 style = RLINES;
200 }
201 }
202
203 if (*argv && fflag) {
204 files = malloc(no_files * sizeof(struct file_info));
205 if (files == NULL)
206 err(1, "failed to allocate memory for file descriptors");
207
208 for (filep = files; (fn = *argv++); filep++) {
209 filep->file_name = fn;
210 filep->fp = fileargs_fopen(fa, filep->file_name, "r");
211 if (filep->fp == NULL ||
212 fstat(fileno(filep->fp), &filep->st)) {
213 if (filep->fp != NULL) {
214 fclose(filep->fp);
215 filep->fp = NULL;
216 }
217 if (!Fflag || errno != ENOENT)
218 ierr(filep->file_name);
219 }
220 }
221 follow(files, style, off);
222 free(files);
223 } else if (*argv) {
224 for (first = 1; (fn = *argv++);) {
225 if ((fp = fileargs_fopen(fa, fn, "r")) == NULL ||
226 fstat(fileno(fp), &sb)) {
227 ierr(fn);
228 continue;
229 }
230 if (vflag || (qflag == 0 && argc > 1)) {
231 printfn(fn, !first);
232 first = 0;
233 }
234
235 if (rflag)
236 reverse(fp, fn, style, off, &sb);
237 else
238 forward(fp, fn, style, off, &sb);
239 }
240 } else {
241 fn = "stdin";
242
243 if (fstat(fileno(stdin), &sb)) {
244 ierr(fn);
245 exit(1);
246 }
247
248 /*
249 * Determine if input is a pipe. 4.4BSD will set the SOCKET
250 * bit in the st_mode field for pipes. Fix this then.
251 */
252 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
253 errno == ESPIPE) {
254 errno = 0;
255 fflag = 0; /* POSIX.2 requires this. */
256 }
257
258 if (rflag) {
259 reverse(stdin, fn, style, off, &sb);
260 } else if (fflag) {
261 file.file_name = fn;
262 file.fp = stdin;
263 file.st = sb;
264 follow(&file, style, off);
265 } else {
266 forward(stdin, fn, style, off, &sb);
267 }
268 }
269 fileargs_free(fa);
270 exit(rval);
271 }
272
273 /*
274 * Convert the obsolete argument form into something that getopt can handle.
275 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
276 * the option argument for a -b, -c or -n option gets converted.
277 */
278 static void
obsolete(char * argv[])279 obsolete(char *argv[])
280 {
281 char *ap, *p, *t;
282 size_t len;
283 char *start;
284
285 while ((ap = *++argv)) {
286 /* Return if "--" or not an option of any form. */
287 if (ap[0] != '-') {
288 if (ap[0] != '+')
289 return;
290 } else if (ap[1] == '-')
291 return;
292
293 switch(*++ap) {
294 /* Old-style option. */
295 case '0': case '1': case '2': case '3': case '4':
296 case '5': case '6': case '7': case '8': case '9':
297
298 /* Malloc space for dash, new option and argument. */
299 len = strlen(*argv);
300 if ((start = p = malloc(len + 3)) == NULL)
301 err(1, "failed to allocate memory");
302 *p++ = '-';
303
304 /*
305 * Go to the end of the option argument. Save off any
306 * trailing options (-3lf) and translate any trailing
307 * output style characters.
308 */
309 t = *argv + len - 1;
310 if (*t == 'F' || *t == 'f' || *t == 'r') {
311 *p++ = *t;
312 *t-- = '\0';
313 }
314 switch(*t) {
315 case 'b':
316 *p++ = 'b';
317 *t = '\0';
318 break;
319 case 'c':
320 *p++ = 'c';
321 *t = '\0';
322 break;
323 case 'l':
324 *t = '\0';
325 /* FALLTHROUGH */
326 case '0': case '1': case '2': case '3': case '4':
327 case '5': case '6': case '7': case '8': case '9':
328 *p++ = 'n';
329 break;
330 default:
331 errx(1, "illegal option -- %s", *argv);
332 }
333 *p++ = *argv[0];
334 (void)strcpy(p, ap);
335 *argv = start;
336 continue;
337
338 /*
339 * Options w/ arguments, skip the argument and continue
340 * with the next option.
341 */
342 case 'b':
343 case 'c':
344 case 'n':
345 if (!ap[1])
346 ++argv;
347 /* FALLTHROUGH */
348 /* Options w/o arguments, continue with the next option. */
349 case 'F':
350 case 'f':
351 case 'r':
352 continue;
353
354 /* Illegal option, return and let getopt handle it. */
355 default:
356 return;
357 }
358 }
359 }
360
361 static void
usage(void)362 usage(void)
363 {
364 (void)fprintf(stderr,
365 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]"
366 " [file ...]\n");
367 exit(1);
368 }
369