xref: /freebsd/bin/cat/cat.c (revision 66fd12cf4896eb08ad8e7a2627537f84ead84dd3)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 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  * Kevin Fall.
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 #if 0
36 #ifndef lint
37 static char const copyright[] =
38 "@(#) Copyright (c) 1989, 1993\n\
39 	The Regents of the University of California.  All rights reserved.\n";
40 #endif /* not lint */
41 #endif
42 
43 #ifndef lint
44 #if 0
45 static char sccsid[] = "@(#)cat.c	8.2 (Berkeley) 4/27/95";
46 #endif
47 #endif /* not lint */
48 #include <sys/cdefs.h>
49 __FBSDID("$FreeBSD$");
50 
51 #include <sys/capsicum.h>
52 #include <sys/param.h>
53 #include <sys/stat.h>
54 #ifndef NO_UDOM_SUPPORT
55 #include <sys/socket.h>
56 #include <sys/un.h>
57 #include <netdb.h>
58 #endif
59 
60 #include <capsicum_helpers.h>
61 #include <ctype.h>
62 #include <err.h>
63 #include <errno.h>
64 #include <fcntl.h>
65 #include <locale.h>
66 #include <stdio.h>
67 #include <stdlib.h>
68 #include <string.h>
69 #include <unistd.h>
70 #include <wchar.h>
71 #include <wctype.h>
72 
73 #include <libcasper.h>
74 #include <casper/cap_fileargs.h>
75 #include <casper/cap_net.h>
76 
77 static int bflag, eflag, lflag, nflag, sflag, tflag, vflag;
78 static int rval;
79 static const char *filename;
80 static fileargs_t *fa;
81 
82 static void usage(void) __dead2;
83 static void scanfiles(char *argv[], int cooked);
84 #ifndef BOOTSTRAP_CAT
85 static void cook_cat(FILE *);
86 static ssize_t in_kernel_copy(int);
87 #endif
88 static void raw_cat(int);
89 
90 #ifndef NO_UDOM_SUPPORT
91 static cap_channel_t *capnet;
92 
93 static int udom_open(const char *path, int flags);
94 #endif
95 
96 /*
97  * Memory strategy threshold, in pages: if physmem is larger than this,
98  * use a large buffer.
99  */
100 #define	PHYSPAGES_THRESHOLD (32 * 1024)
101 
102 /* Maximum buffer size in bytes - do not allow it to grow larger than this. */
103 #define	BUFSIZE_MAX (2 * 1024 * 1024)
104 
105 /*
106  * Small (default) buffer size in bytes. It's inefficient for this to be
107  * smaller than MAXPHYS.
108  */
109 #define	BUFSIZE_SMALL (MAXPHYS)
110 
111 
112 /*
113  * For the bootstrapped cat binary (needed for locked appending to METALOG), we
114  * disable all flags except -l and -u to avoid non-portable function calls.
115  * In the future we may instead want to write a small portable bootstrap tool
116  * that locks the output file before writing to it. However, for now
117  * bootstrapping cat without multibyte support is the simpler solution.
118  */
119 #ifdef BOOTSTRAP_CAT
120 #define SUPPORTED_FLAGS "lu"
121 #else
122 #define SUPPORTED_FLAGS "belnstuv"
123 #endif
124 
125 #ifndef NO_UDOM_SUPPORT
126 static void
127 init_casper_net(cap_channel_t *casper)
128 {
129 	cap_net_limit_t *limit;
130 	int familylimit;
131 
132 	capnet = cap_service_open(casper, "system.net");
133 	if (capnet == NULL)
134 		err(EXIT_FAILURE, "unable to create network service");
135 
136 	limit = cap_net_limit_init(capnet, CAPNET_NAME2ADDR |
137 	    CAPNET_CONNECTDNS);
138 	if (limit == NULL)
139 		err(EXIT_FAILURE, "unable to create limits");
140 
141 	familylimit = AF_LOCAL;
142 	cap_net_limit_name2addr_family(limit, &familylimit, 1);
143 
144 	if (cap_net_limit(limit) < 0)
145 		err(EXIT_FAILURE, "unable to apply limits");
146 }
147 #endif
148 
149 static void
150 init_casper(int argc, char *argv[])
151 {
152 	cap_channel_t *casper;
153 	cap_rights_t rights;
154 
155 	casper = cap_init();
156 	if (casper == NULL)
157 		err(EXIT_FAILURE, "unable to create Casper");
158 
159 	fa = fileargs_cinit(casper, argc, argv, O_RDONLY, 0,
160 	    cap_rights_init(&rights, CAP_READ | CAP_FSTAT | CAP_FCNTL),
161 	    FA_OPEN | FA_REALPATH);
162 	if (fa == NULL)
163 		err(EXIT_FAILURE, "unable to create fileargs");
164 
165 #ifndef NO_UDOM_SUPPORT
166 	init_casper_net(casper);
167 #endif
168 
169 	cap_close(casper);
170 }
171 
172 int
173 main(int argc, char *argv[])
174 {
175 	int ch;
176 	struct flock stdout_lock;
177 
178 	setlocale(LC_CTYPE, "");
179 
180 	while ((ch = getopt(argc, argv, SUPPORTED_FLAGS)) != -1)
181 		switch (ch) {
182 		case 'b':
183 			bflag = nflag = 1;	/* -b implies -n */
184 			break;
185 		case 'e':
186 			eflag = vflag = 1;	/* -e implies -v */
187 			break;
188 		case 'l':
189 			lflag = 1;
190 			break;
191 		case 'n':
192 			nflag = 1;
193 			break;
194 		case 's':
195 			sflag = 1;
196 			break;
197 		case 't':
198 			tflag = vflag = 1;	/* -t implies -v */
199 			break;
200 		case 'u':
201 			setbuf(stdout, NULL);
202 			break;
203 		case 'v':
204 			vflag = 1;
205 			break;
206 		default:
207 			usage();
208 		}
209 	argv += optind;
210 	argc -= optind;
211 
212 	if (lflag) {
213 		stdout_lock.l_len = 0;
214 		stdout_lock.l_start = 0;
215 		stdout_lock.l_type = F_WRLCK;
216 		stdout_lock.l_whence = SEEK_SET;
217 		if (fcntl(STDOUT_FILENO, F_SETLKW, &stdout_lock) == -1)
218 			err(EXIT_FAILURE, "stdout");
219 	}
220 
221 	init_casper(argc, argv);
222 
223 	caph_cache_catpages();
224 
225 	if (caph_enter_casper() < 0)
226 		err(EXIT_FAILURE, "capsicum");
227 
228 	if (bflag || eflag || nflag || sflag || tflag || vflag)
229 		scanfiles(argv, 1);
230 	else
231 		scanfiles(argv, 0);
232 	if (fclose(stdout))
233 		err(1, "stdout");
234 	exit(rval);
235 	/* NOTREACHED */
236 }
237 
238 static void
239 usage(void)
240 {
241 
242 	fprintf(stderr, "usage: cat [-" SUPPORTED_FLAGS "] [file ...]\n");
243 	exit(1);
244 	/* NOTREACHED */
245 }
246 
247 static void
248 scanfiles(char *argv[], int cooked __unused)
249 {
250 	int fd, i;
251 	char *path;
252 #ifndef BOOTSTRAP_CAT
253 	FILE *fp;
254 #endif
255 
256 	i = 0;
257 	fd = -1;
258 	while ((path = argv[i]) != NULL || i == 0) {
259 		if (path == NULL || strcmp(path, "-") == 0) {
260 			filename = "stdin";
261 			fd = STDIN_FILENO;
262 		} else {
263 			filename = path;
264 			fd = fileargs_open(fa, path);
265 #ifndef NO_UDOM_SUPPORT
266 			if (fd < 0 && errno == EOPNOTSUPP)
267 				fd = udom_open(path, O_RDONLY);
268 #endif
269 		}
270 		if (fd < 0) {
271 			warn("%s", path);
272 			rval = 1;
273 #ifndef BOOTSTRAP_CAT
274 		} else if (cooked) {
275 			if (fd == STDIN_FILENO)
276 				cook_cat(stdin);
277 			else {
278 				fp = fdopen(fd, "r");
279 				cook_cat(fp);
280 				fclose(fp);
281 			}
282 #endif
283 		} else {
284 #ifndef BOOTSTRAP_CAT
285 			if (in_kernel_copy(fd) == -1) {
286 				if (errno == EINVAL || errno == EBADF)
287 					raw_cat(fd);
288 				else
289 					err(1, "stdout");
290 			}
291 #else
292 			raw_cat(fd);
293 #endif
294 			if (fd != STDIN_FILENO)
295 				close(fd);
296 		}
297 		if (path == NULL)
298 			break;
299 		++i;
300 	}
301 }
302 
303 #ifndef BOOTSTRAP_CAT
304 static void
305 cook_cat(FILE *fp)
306 {
307 	int ch, gobble, line, prev;
308 	wint_t wch;
309 
310 	/* Reset EOF condition on stdin. */
311 	if (fp == stdin && feof(stdin))
312 		clearerr(stdin);
313 
314 	line = gobble = 0;
315 	for (prev = '\n'; (ch = getc(fp)) != EOF; prev = ch) {
316 		if (prev == '\n') {
317 			if (sflag) {
318 				if (ch == '\n') {
319 					if (gobble)
320 						continue;
321 					gobble = 1;
322 				} else
323 					gobble = 0;
324 			}
325 			if (nflag) {
326 				if (!bflag || ch != '\n') {
327 					(void)fprintf(stdout, "%6d\t", ++line);
328 					if (ferror(stdout))
329 						break;
330 				} else if (eflag) {
331 					(void)fprintf(stdout, "%6s\t", "");
332 					if (ferror(stdout))
333 						break;
334 				}
335 			}
336 		}
337 		if (ch == '\n') {
338 			if (eflag && putchar('$') == EOF)
339 				break;
340 		} else if (ch == '\t') {
341 			if (tflag) {
342 				if (putchar('^') == EOF || putchar('I') == EOF)
343 					break;
344 				continue;
345 			}
346 		} else if (vflag) {
347 			(void)ungetc(ch, fp);
348 			/*
349 			 * Our getwc(3) doesn't change file position
350 			 * on error.
351 			 */
352 			if ((wch = getwc(fp)) == WEOF) {
353 				if (ferror(fp) && errno == EILSEQ) {
354 					clearerr(fp);
355 					/* Resync attempt. */
356 					memset(&fp->_mbstate, 0, sizeof(mbstate_t));
357 					if ((ch = getc(fp)) == EOF)
358 						break;
359 					wch = ch;
360 					goto ilseq;
361 				} else
362 					break;
363 			}
364 			if (!iswascii(wch) && !iswprint(wch)) {
365 ilseq:
366 				if (putchar('M') == EOF || putchar('-') == EOF)
367 					break;
368 				wch = toascii(wch);
369 			}
370 			if (iswcntrl(wch)) {
371 				ch = toascii(wch);
372 				ch = (ch == '\177') ? '?' : (ch | 0100);
373 				if (putchar('^') == EOF || putchar(ch) == EOF)
374 					break;
375 				continue;
376 			}
377 			if (putwchar(wch) == WEOF)
378 				break;
379 			ch = -1;
380 			continue;
381 		}
382 		if (putchar(ch) == EOF)
383 			break;
384 	}
385 	if (ferror(fp)) {
386 		warn("%s", filename);
387 		rval = 1;
388 		clearerr(fp);
389 	}
390 	if (ferror(stdout))
391 		err(1, "stdout");
392 }
393 
394 static ssize_t
395 in_kernel_copy(int rfd)
396 {
397 	int wfd;
398 	ssize_t ret;
399 
400 	wfd = fileno(stdout);
401 	ret = 1;
402 
403 	while (ret > 0)
404 		ret = copy_file_range(rfd, NULL, wfd, NULL, SSIZE_MAX, 0);
405 
406 	return (ret);
407 }
408 #endif /* BOOTSTRAP_CAT */
409 
410 static void
411 raw_cat(int rfd)
412 {
413 	long pagesize;
414 	int off, wfd;
415 	ssize_t nr, nw;
416 	static size_t bsize;
417 	static char *buf = NULL;
418 	struct stat sbuf;
419 
420 	wfd = fileno(stdout);
421 	if (buf == NULL) {
422 		if (fstat(wfd, &sbuf))
423 			err(1, "stdout");
424 		if (S_ISREG(sbuf.st_mode)) {
425 			/* If there's plenty of RAM, use a large copy buffer */
426 			if (sysconf(_SC_PHYS_PAGES) > PHYSPAGES_THRESHOLD)
427 				bsize = MIN(BUFSIZE_MAX, MAXPHYS * 8);
428 			else
429 				bsize = BUFSIZE_SMALL;
430 		} else {
431 			bsize = sbuf.st_blksize;
432 			pagesize = sysconf(_SC_PAGESIZE);
433 			if (pagesize > 0)
434 				bsize = MAX(bsize, (size_t)pagesize);
435 		}
436 		if ((buf = malloc(bsize)) == NULL)
437 			err(1, "malloc() failure of IO buffer");
438 	}
439 	while ((nr = read(rfd, buf, bsize)) > 0)
440 		for (off = 0; nr; nr -= nw, off += nw)
441 			if ((nw = write(wfd, buf + off, (size_t)nr)) < 0)
442 				err(1, "stdout");
443 	if (nr < 0) {
444 		warn("%s", filename);
445 		rval = 1;
446 	}
447 }
448 
449 #ifndef NO_UDOM_SUPPORT
450 
451 static int
452 udom_open(const char *path, int flags)
453 {
454 	struct addrinfo hints, *res, *res0;
455 	char rpath[PATH_MAX];
456 	int error, fd, serrno;
457 	cap_rights_t rights;
458 
459 	/*
460 	 * Construct the unix domain socket address and attempt to connect.
461 	 */
462 	bzero(&hints, sizeof(hints));
463 	hints.ai_family = AF_LOCAL;
464 
465 	if (fileargs_realpath(fa, path, rpath) == NULL)
466 		return (-1);
467 
468 	error = cap_getaddrinfo(capnet, rpath, NULL, &hints, &res0);
469 	if (error) {
470 		warn("%s", gai_strerror(error));
471 		errno = EINVAL;
472 		return (-1);
473 	}
474 	cap_rights_init(&rights, CAP_CONNECT, CAP_READ, CAP_WRITE,
475 	    CAP_SHUTDOWN, CAP_FSTAT, CAP_FCNTL);
476 
477 	/* Default error if something goes wrong. */
478 	serrno = EINVAL;
479 
480 	for (res = res0; res != NULL; res = res->ai_next) {
481 		fd = socket(res->ai_family, res->ai_socktype,
482 		    res->ai_protocol);
483 		if (fd < 0) {
484 			serrno = errno;
485 			freeaddrinfo(res0);
486 			errno = serrno;
487 			return (-1);
488 		}
489 		if (caph_rights_limit(fd, &rights) < 0) {
490 			serrno = errno;
491 			close(fd);
492 			freeaddrinfo(res0);
493 			errno = serrno;
494 			return (-1);
495 		}
496 		error = cap_connect(capnet, fd, res->ai_addr, res->ai_addrlen);
497 		if (error == 0)
498 			break;
499 		else {
500 			serrno = errno;
501 			close(fd);
502 		}
503 	}
504 	freeaddrinfo(res0);
505 
506 	if (res == NULL) {
507 		errno = serrno;
508 		return (-1);
509 	}
510 
511 	/*
512 	 * handle the open flags by shutting down appropriate directions
513 	 */
514 
515 	switch (flags & O_ACCMODE) {
516 	case O_RDONLY:
517 		cap_rights_clear(&rights, CAP_WRITE);
518 		if (shutdown(fd, SHUT_WR) == -1)
519 			warn(NULL);
520 		break;
521 	case O_WRONLY:
522 		cap_rights_clear(&rights, CAP_READ);
523 		if (shutdown(fd, SHUT_RD) == -1)
524 			warn(NULL);
525 		break;
526 	default:
527 		break;
528 	}
529 
530 	cap_rights_clear(&rights, CAP_CONNECT, CAP_SHUTDOWN);
531 	if (caph_rights_limit(fd, &rights) < 0) {
532 		serrno = errno;
533 		close(fd);
534 		errno = serrno;
535 		return (-1);
536 	}
537 	return (fd);
538 }
539 
540 #endif
541