xref: /freebsd/bin/cp/utils.c (revision 7899f917b1c0ea178f1d2be0cfb452086d079d23)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1991, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/param.h>
33 #include <sys/acl.h>
34 #include <sys/stat.h>
35 
36 #include <err.h>
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <fts.h>
40 #include <limits.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <sysexits.h>
44 #include <unistd.h>
45 
46 #include "extern.h"
47 
48 #define	cp_pct(x, y)	((y == 0) ? 0 : (int)(100.0 * (x) / (y)))
49 
50 /*
51  * Memory strategy threshold, in pages: if physmem is larger then this, use a
52  * large buffer.
53  */
54 #define PHYSPAGES_THRESHOLD (32*1024)
55 
56 /* Maximum buffer size in bytes - do not allow it to grow larger than this. */
57 #define BUFSIZE_MAX (2*1024*1024)
58 
59 /*
60  * Small (default) buffer size in bytes. It's inefficient for this to be
61  * smaller than MAXPHYS.
62  */
63 #define BUFSIZE_SMALL (MAXPHYS)
64 
65 /*
66  * Prompt used in -i case.
67  */
68 #define YESNO "(y/n [n]) "
69 
70 static ssize_t
71 copy_fallback(int from_fd, int to_fd)
72 {
73 	static char *buf = NULL;
74 	static size_t bufsize;
75 	ssize_t rcount, wresid, wcount = 0;
76 	char *bufp;
77 
78 	if (buf == NULL) {
79 		if (sysconf(_SC_PHYS_PAGES) > PHYSPAGES_THRESHOLD)
80 			bufsize = MIN(BUFSIZE_MAX, MAXPHYS * 8);
81 		else
82 			bufsize = BUFSIZE_SMALL;
83 		buf = malloc(bufsize);
84 		if (buf == NULL)
85 			err(1, "Not enough memory");
86 	}
87 	rcount = read(from_fd, buf, bufsize);
88 	if (rcount <= 0)
89 		return (rcount);
90 	for (bufp = buf, wresid = rcount; ; bufp += wcount, wresid -= wcount) {
91 		wcount = write(to_fd, bufp, wresid);
92 		if (wcount <= 0)
93 			break;
94 		if (wcount >= wresid)
95 			break;
96 	}
97 	return (wcount < 0 ? wcount : rcount);
98 }
99 
100 int
101 copy_file(const FTSENT *entp, int dne)
102 {
103 	struct stat sb, *fs;
104 	ssize_t wcount;
105 	off_t wtotal;
106 	int ch, checkch, from_fd, rval, to_fd;
107 	int use_copy_file_range = 1;
108 
109 	fs = entp->fts_statp;
110 	from_fd = to_fd = -1;
111 	if (!lflag && !sflag) {
112 		if ((from_fd = open(entp->fts_path, O_RDONLY, 0)) < 0 ||
113 		    fstat(from_fd, &sb) != 0) {
114 			warn("%s", entp->fts_path);
115 			if (from_fd >= 0)
116 				(void)close(from_fd);
117 			return (1);
118 		}
119 		/*
120 		 * Check that the file hasn't been replaced with one of a
121 		 * different type.  This can happen if we've been asked to
122 		 * copy something which is actively being modified and
123 		 * lost the race, or if we've been asked to copy something
124 		 * like /proc/X/fd/Y which stat(2) reports as S_IFREG but
125 		 * is actually something else once you open it.
126 		 */
127 		if ((sb.st_mode & S_IFMT) != (fs->st_mode & S_IFMT)) {
128 			warnx("%s: File changed", entp->fts_path);
129 			(void)close(from_fd);
130 			return (1);
131 		}
132 	}
133 
134 	/*
135 	 * If the file exists and we're interactive, verify with the user.
136 	 * If the file DNE, set the mode to be the from file, minus setuid
137 	 * bits, modified by the umask; arguably wrong, but it makes copying
138 	 * executables work right and it's been that way forever.  (The
139 	 * other choice is 666 or'ed with the execute bits on the from file
140 	 * modified by the umask.)
141 	 */
142 	if (!dne) {
143 		if (nflag) {
144 			if (vflag)
145 				printf("%s not overwritten\n", to.p_path);
146 			rval = 1;
147 			goto done;
148 		} else if (iflag) {
149 			(void)fprintf(stderr, "overwrite %s? %s",
150 			    to.p_path, YESNO);
151 			checkch = ch = getchar();
152 			while (ch != '\n' && ch != EOF)
153 				ch = getchar();
154 			if (checkch != 'y' && checkch != 'Y') {
155 				(void)fprintf(stderr, "not overwritten\n");
156 				rval = 1;
157 				goto done;
158 			}
159 		}
160 
161 		if (fflag) {
162 			/* remove existing destination file */
163 			(void)unlink(to.p_path);
164 			dne = 1;
165 		}
166 	}
167 
168 	rval = 0;
169 
170 	if (lflag) {
171 		if (link(entp->fts_path, to.p_path) != 0) {
172 			warn("%s", to.p_path);
173 			rval = 1;
174 		}
175 		goto done;
176 	}
177 
178 	if (sflag) {
179 		if (symlink(entp->fts_path, to.p_path) != 0) {
180 			warn("%s", to.p_path);
181 			rval = 1;
182 		}
183 		goto done;
184 	}
185 
186 	if (!dne) {
187 		/* overwrite existing destination file */
188 		to_fd = open(to.p_path, O_WRONLY | O_TRUNC, 0);
189 	} else {
190 		/* create new destination file */
191 		to_fd = open(to.p_path, O_WRONLY | O_TRUNC | O_CREAT,
192 		    fs->st_mode & ~(S_ISUID | S_ISGID));
193 	}
194 	if (to_fd == -1) {
195 		warn("%s", to.p_path);
196 		rval = 1;
197 		goto done;
198 	}
199 
200 	wtotal = 0;
201 	do {
202 		if (use_copy_file_range) {
203 			wcount = copy_file_range(from_fd, NULL,
204 			    to_fd, NULL, SSIZE_MAX, 0);
205 			if (wcount < 0 && errno == EINVAL) {
206 				/* probably a non-seekable descriptor */
207 				use_copy_file_range = 0;
208 			}
209 		}
210 		if (!use_copy_file_range) {
211 			wcount = copy_fallback(from_fd, to_fd);
212 		}
213 		wtotal += wcount;
214 		if (info) {
215 			info = 0;
216 			(void)fprintf(stderr,
217 			    "%s -> %s %3d%%\n",
218 			    entp->fts_path, to.p_path,
219 			    cp_pct(wtotal, fs->st_size));
220 		}
221 	} while (wcount > 0);
222 	if (wcount < 0) {
223 		warn("%s", entp->fts_path);
224 		rval = 1;
225 	}
226 
227 	/*
228 	 * Don't remove the target even after an error.  The target might
229 	 * not be a regular file, or its attributes might be important,
230 	 * or its contents might be irreplaceable.  It would only be safe
231 	 * to remove it if we created it and its length is 0.
232 	 */
233 	if (pflag && setfile(fs, to_fd))
234 		rval = 1;
235 	if (pflag && preserve_fd_acls(from_fd, to_fd) != 0)
236 		rval = 1;
237 	if (close(to_fd)) {
238 		warn("%s", to.p_path);
239 		rval = 1;
240 	}
241 
242 done:
243 	if (from_fd != -1)
244 		(void)close(from_fd);
245 	return (rval);
246 }
247 
248 int
249 copy_link(const FTSENT *p, int exists)
250 {
251 	ssize_t len;
252 	char llink[PATH_MAX];
253 
254 	if (exists && nflag) {
255 		if (vflag)
256 			printf("%s not overwritten\n", to.p_path);
257 		return (1);
258 	}
259 	if ((len = readlink(p->fts_path, llink, sizeof(llink) - 1)) == -1) {
260 		warn("readlink: %s", p->fts_path);
261 		return (1);
262 	}
263 	llink[len] = '\0';
264 	if (exists && unlink(to.p_path)) {
265 		warn("unlink: %s", to.p_path);
266 		return (1);
267 	}
268 	if (symlink(llink, to.p_path)) {
269 		warn("symlink: %s", llink);
270 		return (1);
271 	}
272 	return (pflag ? setfile(p->fts_statp, -1) : 0);
273 }
274 
275 int
276 copy_fifo(struct stat *from_stat, int exists)
277 {
278 
279 	if (exists && nflag) {
280 		if (vflag)
281 			printf("%s not overwritten\n", to.p_path);
282 		return (1);
283 	}
284 	if (exists && unlink(to.p_path)) {
285 		warn("unlink: %s", to.p_path);
286 		return (1);
287 	}
288 	if (mkfifo(to.p_path, from_stat->st_mode)) {
289 		warn("mkfifo: %s", to.p_path);
290 		return (1);
291 	}
292 	return (pflag ? setfile(from_stat, -1) : 0);
293 }
294 
295 int
296 copy_special(struct stat *from_stat, int exists)
297 {
298 
299 	if (exists && nflag) {
300 		if (vflag)
301 			printf("%s not overwritten\n", to.p_path);
302 		return (1);
303 	}
304 	if (exists && unlink(to.p_path)) {
305 		warn("unlink: %s", to.p_path);
306 		return (1);
307 	}
308 	if (mknod(to.p_path, from_stat->st_mode, from_stat->st_rdev)) {
309 		warn("mknod: %s", to.p_path);
310 		return (1);
311 	}
312 	return (pflag ? setfile(from_stat, -1) : 0);
313 }
314 
315 int
316 setfile(struct stat *fs, int fd)
317 {
318 	static struct timespec tspec[2];
319 	struct stat ts;
320 	int rval, gotstat, islink, fdval;
321 
322 	rval = 0;
323 	fdval = fd != -1;
324 	islink = !fdval && S_ISLNK(fs->st_mode);
325 	fs->st_mode &= S_ISUID | S_ISGID | S_ISVTX |
326 	    S_IRWXU | S_IRWXG | S_IRWXO;
327 
328 	tspec[0] = fs->st_atim;
329 	tspec[1] = fs->st_mtim;
330 	if (fdval ? futimens(fd, tspec) : utimensat(AT_FDCWD, to.p_path, tspec,
331 	    islink ? AT_SYMLINK_NOFOLLOW : 0)) {
332 		warn("utimensat: %s", to.p_path);
333 		rval = 1;
334 	}
335 	if (fdval ? fstat(fd, &ts) :
336 	    (islink ? lstat(to.p_path, &ts) : stat(to.p_path, &ts)))
337 		gotstat = 0;
338 	else {
339 		gotstat = 1;
340 		ts.st_mode &= S_ISUID | S_ISGID | S_ISVTX |
341 		    S_IRWXU | S_IRWXG | S_IRWXO;
342 	}
343 	/*
344 	 * Changing the ownership probably won't succeed, unless we're root
345 	 * or POSIX_CHOWN_RESTRICTED is not set.  Set uid/gid before setting
346 	 * the mode; current BSD behavior is to remove all setuid bits on
347 	 * chown.  If chown fails, lose setuid/setgid bits.
348 	 */
349 	if (!gotstat || fs->st_uid != ts.st_uid || fs->st_gid != ts.st_gid)
350 		if (fdval ? fchown(fd, fs->st_uid, fs->st_gid) :
351 		    (islink ? lchown(to.p_path, fs->st_uid, fs->st_gid) :
352 		    chown(to.p_path, fs->st_uid, fs->st_gid))) {
353 			if (errno != EPERM) {
354 				warn("chown: %s", to.p_path);
355 				rval = 1;
356 			}
357 			fs->st_mode &= ~(S_ISUID | S_ISGID);
358 		}
359 
360 	if (!gotstat || fs->st_mode != ts.st_mode)
361 		if (fdval ? fchmod(fd, fs->st_mode) :
362 		    (islink ? lchmod(to.p_path, fs->st_mode) :
363 		    chmod(to.p_path, fs->st_mode))) {
364 			warn("chmod: %s", to.p_path);
365 			rval = 1;
366 		}
367 
368 	if (!Nflag && (!gotstat || fs->st_flags != ts.st_flags))
369 		if (fdval ?
370 		    fchflags(fd, fs->st_flags) :
371 		    (islink ? lchflags(to.p_path, fs->st_flags) :
372 		    chflags(to.p_path, fs->st_flags))) {
373 			/*
374 			 * NFS doesn't support chflags; ignore errors unless
375 			 * there's reason to believe we're losing bits.  (Note,
376 			 * this still won't be right if the server supports
377 			 * flags and we were trying to *remove* flags on a file
378 			 * that we copied, i.e., that we didn't create.)
379 			 */
380 			if (errno != EOPNOTSUPP || fs->st_flags != 0) {
381 				warn("chflags: %s", to.p_path);
382 				rval = 1;
383 			}
384 		}
385 
386 	return (rval);
387 }
388 
389 int
390 preserve_fd_acls(int source_fd, int dest_fd)
391 {
392 	acl_t acl;
393 	acl_type_t acl_type;
394 	int acl_supported = 0, ret, trivial;
395 
396 	ret = fpathconf(source_fd, _PC_ACL_NFS4);
397 	if (ret > 0 ) {
398 		acl_supported = 1;
399 		acl_type = ACL_TYPE_NFS4;
400 	} else if (ret < 0 && errno != EINVAL) {
401 		warn("fpathconf(..., _PC_ACL_NFS4) failed for %s", to.p_path);
402 		return (1);
403 	}
404 	if (acl_supported == 0) {
405 		ret = fpathconf(source_fd, _PC_ACL_EXTENDED);
406 		if (ret > 0 ) {
407 			acl_supported = 1;
408 			acl_type = ACL_TYPE_ACCESS;
409 		} else if (ret < 0 && errno != EINVAL) {
410 			warn("fpathconf(..., _PC_ACL_EXTENDED) failed for %s",
411 			    to.p_path);
412 			return (1);
413 		}
414 	}
415 	if (acl_supported == 0)
416 		return (0);
417 
418 	acl = acl_get_fd_np(source_fd, acl_type);
419 	if (acl == NULL) {
420 		warn("failed to get acl entries while setting %s", to.p_path);
421 		return (1);
422 	}
423 	if (acl_is_trivial_np(acl, &trivial)) {
424 		warn("acl_is_trivial() failed for %s", to.p_path);
425 		acl_free(acl);
426 		return (1);
427 	}
428 	if (trivial) {
429 		acl_free(acl);
430 		return (0);
431 	}
432 	if (acl_set_fd_np(dest_fd, acl, acl_type) < 0) {
433 		warn("failed to set acl entries for %s", to.p_path);
434 		acl_free(acl);
435 		return (1);
436 	}
437 	acl_free(acl);
438 	return (0);
439 }
440 
441 int
442 preserve_dir_acls(struct stat *fs, char *source_dir, char *dest_dir)
443 {
444 	acl_t (*aclgetf)(const char *, acl_type_t);
445 	int (*aclsetf)(const char *, acl_type_t, acl_t);
446 	struct acl *aclp;
447 	acl_t acl;
448 	acl_type_t acl_type;
449 	int acl_supported = 0, ret, trivial;
450 
451 	ret = pathconf(source_dir, _PC_ACL_NFS4);
452 	if (ret > 0) {
453 		acl_supported = 1;
454 		acl_type = ACL_TYPE_NFS4;
455 	} else if (ret < 0 && errno != EINVAL) {
456 		warn("fpathconf(..., _PC_ACL_NFS4) failed for %s", source_dir);
457 		return (1);
458 	}
459 	if (acl_supported == 0) {
460 		ret = pathconf(source_dir, _PC_ACL_EXTENDED);
461 		if (ret > 0) {
462 			acl_supported = 1;
463 			acl_type = ACL_TYPE_ACCESS;
464 		} else if (ret < 0 && errno != EINVAL) {
465 			warn("fpathconf(..., _PC_ACL_EXTENDED) failed for %s",
466 			    source_dir);
467 			return (1);
468 		}
469 	}
470 	if (acl_supported == 0)
471 		return (0);
472 
473 	/*
474 	 * If the file is a link we will not follow it.
475 	 */
476 	if (S_ISLNK(fs->st_mode)) {
477 		aclgetf = acl_get_link_np;
478 		aclsetf = acl_set_link_np;
479 	} else {
480 		aclgetf = acl_get_file;
481 		aclsetf = acl_set_file;
482 	}
483 	if (acl_type == ACL_TYPE_ACCESS) {
484 		/*
485 		 * Even if there is no ACL_TYPE_DEFAULT entry here, a zero
486 		 * size ACL will be returned. So it is not safe to simply
487 		 * check the pointer to see if the default ACL is present.
488 		 */
489 		acl = aclgetf(source_dir, ACL_TYPE_DEFAULT);
490 		if (acl == NULL) {
491 			warn("failed to get default acl entries on %s",
492 			    source_dir);
493 			return (1);
494 		}
495 		aclp = &acl->ats_acl;
496 		if (aclp->acl_cnt != 0 && aclsetf(dest_dir,
497 		    ACL_TYPE_DEFAULT, acl) < 0) {
498 			warn("failed to set default acl entries on %s",
499 			    dest_dir);
500 			acl_free(acl);
501 			return (1);
502 		}
503 		acl_free(acl);
504 	}
505 	acl = aclgetf(source_dir, acl_type);
506 	if (acl == NULL) {
507 		warn("failed to get acl entries on %s", source_dir);
508 		return (1);
509 	}
510 	if (acl_is_trivial_np(acl, &trivial)) {
511 		warn("acl_is_trivial() failed on %s", source_dir);
512 		acl_free(acl);
513 		return (1);
514 	}
515 	if (trivial) {
516 		acl_free(acl);
517 		return (0);
518 	}
519 	if (aclsetf(dest_dir, acl_type, acl) < 0) {
520 		warn("failed to set acl entries on %s", dest_dir);
521 		acl_free(acl);
522 		return (1);
523 	}
524 	acl_free(acl);
525 	return (0);
526 }
527 
528 void
529 usage(void)
530 {
531 
532 	(void)fprintf(stderr, "%s\n%s\n",
533 	    "usage: cp [-R [-H | -L | -P]] [-f | -i | -n] [-alpsvx] "
534 	    "source_file target_file",
535 	    "       cp [-R [-H | -L | -P]] [-f | -i | -n] [-alpsvx] "
536 	    "source_file ... "
537 	    "target_directory");
538 	exit(EX_USAGE);
539 }
540