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Revision 365643 - (show annotations) (download)
Fri Sep 11 20:49:36 2020 UTC (3 years, 10 months ago) by asomers
File MIME type: text/plain
File size: 14775 byte(s)
cp: fall back to read/write if copy_file_range fails

Even though copy_file_range has a file-system agnostic version, it still
fails on devfs (perhaps because the file descriptor is non-seekable?) In
that case, fallback to old-fashioned read/write. Fixes
"cp /dev/null /tmp/null"

PR:		249248
Reported by:	Michael Butler
Reviewed by:	mjg
MFC-With:	365549
Differential Revision:	https://reviews.freebsd.org/D26395

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 #ifndef lint
33 #if 0
34 static char sccsid[] = "@(#)utils.c 8.3 (Berkeley) 4/1/94";
35 #endif
36 #endif /* not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39
40 #include <sys/types.h>
41 #include <sys/acl.h>
42 #include <sys/param.h>
43 #include <sys/stat.h>
44 #ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
45 #include <sys/mman.h>
46 #endif
47
48 #include <err.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <fts.h>
52 #include <limits.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <sysexits.h>
56 #include <unistd.h>
57
58 #include "extern.h"
59
60 #define cp_pct(x, y) ((y == 0) ? 0 : (int)(100.0 * (x) / (y)))
61
62 /*
63 * Memory strategy threshold, in pages: if physmem is larger then this, use a
64 * large buffer.
65 */
66 #define PHYSPAGES_THRESHOLD (32*1024)
67
68 /* Maximum buffer size in bytes - do not allow it to grow larger than this. */
69 #define BUFSIZE_MAX (2*1024*1024)
70
71 /*
72 * Small (default) buffer size in bytes. It's inefficient for this to be
73 * smaller than MAXPHYS.
74 */
75 #define BUFSIZE_SMALL (MAXPHYS)
76
77 static int
78 copy_fallback(int from_fd, int to_fd, char *buf, size_t bufsize)
79 {
80 int rcount;
81 ssize_t wresid, wcount = 0;
82 char *bufp;
83
84 rcount = read(from_fd, buf, bufsize);
85 if (rcount <= 0)
86 return (rcount);
87 for (bufp = buf, wresid = rcount; ; bufp += wcount, wresid -= wcount) {
88 wcount = write(to_fd, bufp, wresid);
89 if (wcount <= 0)
90 break;
91 if (wcount >= (ssize_t)wresid)
92 break;
93 }
94 return (wcount < 0 ? wcount : rcount);
95 }
96
97 int
98 copy_file(const FTSENT *entp, int dne)
99 {
100 static char *buf = NULL;
101 static size_t bufsize;
102 struct stat *fs;
103 ssize_t wcount;
104 size_t wresid;
105 off_t wtotal;
106 int ch, checkch, from_fd, rcount, rval, to_fd;
107 char *bufp;
108 #ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
109 char *p;
110 #endif
111 int use_copy_file_range = 1;
112
113 from_fd = to_fd = -1;
114 if (!lflag && !sflag &&
115 (from_fd = open(entp->fts_path, O_RDONLY, 0)) == -1) {
116 warn("%s", entp->fts_path);
117 return (1);
118 }
119
120 fs = entp->fts_statp;
121
122 /*
123 * If the file exists and we're interactive, verify with the user.
124 * If the file DNE, set the mode to be the from file, minus setuid
125 * bits, modified by the umask; arguably wrong, but it makes copying
126 * executables work right and it's been that way forever. (The
127 * other choice is 666 or'ed with the execute bits on the from file
128 * modified by the umask.)
129 */
130 if (!dne) {
131 #define YESNO "(y/n [n]) "
132 if (nflag) {
133 if (vflag)
134 printf("%s not overwritten\n", to.p_path);
135 rval = 1;
136 goto done;
137 } else if (iflag) {
138 (void)fprintf(stderr, "overwrite %s? %s",
139 to.p_path, YESNO);
140 checkch = ch = getchar();
141 while (ch != '\n' && ch != EOF)
142 ch = getchar();
143 if (checkch != 'y' && checkch != 'Y') {
144 (void)fprintf(stderr, "not overwritten\n");
145 rval = 1;
146 goto done;
147 }
148 }
149
150 if (fflag) {
151 /*
152 * Remove existing destination file name create a new
153 * file.
154 */
155 (void)unlink(to.p_path);
156 if (!lflag && !sflag) {
157 to_fd = open(to.p_path,
158 O_WRONLY | O_TRUNC | O_CREAT,
159 fs->st_mode & ~(S_ISUID | S_ISGID));
160 }
161 } else if (!lflag && !sflag) {
162 /* Overwrite existing destination file name. */
163 to_fd = open(to.p_path, O_WRONLY | O_TRUNC, 0);
164 }
165 } else if (!lflag && !sflag) {
166 to_fd = open(to.p_path, O_WRONLY | O_TRUNC | O_CREAT,
167 fs->st_mode & ~(S_ISUID | S_ISGID));
168 }
169
170 if (!lflag && !sflag && to_fd == -1) {
171 warn("%s", to.p_path);
172 rval = 1;
173 goto done;
174 }
175
176 rval = 0;
177
178 if (!lflag && !sflag) {
179 /*
180 * Mmap and write if less than 8M (the limit is so we don't
181 * totally trash memory on big files. This is really a minor
182 * hack, but it wins some CPU back.
183 * Some filesystems, such as smbnetfs, don't support mmap,
184 * so this is a best-effort attempt.
185 */
186 #ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
187 if (S_ISREG(fs->st_mode) && fs->st_size > 0 &&
188 fs->st_size <= 8 * 1024 * 1024 &&
189 (p = mmap(NULL, (size_t)fs->st_size, PROT_READ,
190 MAP_SHARED, from_fd, (off_t)0)) != MAP_FAILED) {
191 wtotal = 0;
192 for (bufp = p, wresid = fs->st_size; ;
193 bufp += wcount, wresid -= (size_t)wcount) {
194 wcount = write(to_fd, bufp, wresid);
195 if (wcount <= 0)
196 break;
197 wtotal += wcount;
198 if (info) {
199 info = 0;
200 (void)fprintf(stderr,
201 "%s -> %s %3d%%\n",
202 entp->fts_path, to.p_path,
203 cp_pct(wtotal, fs->st_size));
204 }
205 if (wcount >= (ssize_t)wresid)
206 break;
207 }
208 if (wcount != (ssize_t)wresid) {
209 warn("%s", to.p_path);
210 rval = 1;
211 }
212 /* Some systems don't unmap on close(2). */
213 if (munmap(p, fs->st_size) < 0) {
214 warn("%s", entp->fts_path);
215 rval = 1;
216 }
217 } else
218 #endif
219 {
220 if (buf == NULL) {
221 /*
222 * Note that buf and bufsize are static. If
223 * malloc() fails, it will fail at the start
224 * and not copy only some files.
225 */
226 if (sysconf(_SC_PHYS_PAGES) >
227 PHYSPAGES_THRESHOLD)
228 bufsize = MIN(BUFSIZE_MAX, MAXPHYS * 8);
229 else
230 bufsize = BUFSIZE_SMALL;
231 buf = malloc(bufsize);
232 if (buf == NULL)
233 err(1, "Not enough memory");
234 }
235 wtotal = 0;
236 do {
237 if (use_copy_file_range) {
238 rcount = copy_file_range(from_fd, NULL,
239 to_fd, NULL, bufsize, 0);
240 if (rcount < 0 && errno == EINVAL) {
241 /* Prob a non-seekable FD */
242 use_copy_file_range = 0;
243 }
244 }
245 if (!use_copy_file_range) {
246 rcount = copy_fallback(from_fd, to_fd,
247 buf, bufsize);
248 }
249 wtotal += rcount;
250 if (info) {
251 info = 0;
252 (void)fprintf(stderr,
253 "%s -> %s %3d%%\n",
254 entp->fts_path, to.p_path,
255 cp_pct(wtotal, fs->st_size));
256 }
257 } while (rcount > 0);
258 if (rcount < 0) {
259 warn("%s", entp->fts_path);
260 rval = 1;
261 }
262 }
263 } else if (lflag) {
264 if (link(entp->fts_path, to.p_path)) {
265 warn("%s", to.p_path);
266 rval = 1;
267 }
268 } else if (sflag) {
269 if (symlink(entp->fts_path, to.p_path)) {
270 warn("%s", to.p_path);
271 rval = 1;
272 }
273 }
274
275 /*
276 * Don't remove the target even after an error. The target might
277 * not be a regular file, or its attributes might be important,
278 * or its contents might be irreplaceable. It would only be safe
279 * to remove it if we created it and its length is 0.
280 */
281
282 if (!lflag && !sflag) {
283 if (pflag && setfile(fs, to_fd))
284 rval = 1;
285 if (pflag && preserve_fd_acls(from_fd, to_fd) != 0)
286 rval = 1;
287 if (close(to_fd)) {
288 warn("%s", to.p_path);
289 rval = 1;
290 }
291 }
292
293 done:
294 if (from_fd != -1)
295 (void)close(from_fd);
296 return (rval);
297 }
298
299 int
300 copy_link(const FTSENT *p, int exists)
301 {
302 int len;
303 char llink[PATH_MAX];
304
305 if (exists && nflag) {
306 if (vflag)
307 printf("%s not overwritten\n", to.p_path);
308 return (1);
309 }
310 if ((len = readlink(p->fts_path, llink, sizeof(llink) - 1)) == -1) {
311 warn("readlink: %s", p->fts_path);
312 return (1);
313 }
314 llink[len] = '\0';
315 if (exists && unlink(to.p_path)) {
316 warn("unlink: %s", to.p_path);
317 return (1);
318 }
319 if (symlink(llink, to.p_path)) {
320 warn("symlink: %s", llink);
321 return (1);
322 }
323 return (pflag ? setfile(p->fts_statp, -1) : 0);
324 }
325
326 int
327 copy_fifo(struct stat *from_stat, int exists)
328 {
329
330 if (exists && nflag) {
331 if (vflag)
332 printf("%s not overwritten\n", to.p_path);
333 return (1);
334 }
335 if (exists && unlink(to.p_path)) {
336 warn("unlink: %s", to.p_path);
337 return (1);
338 }
339 if (mkfifo(to.p_path, from_stat->st_mode)) {
340 warn("mkfifo: %s", to.p_path);
341 return (1);
342 }
343 return (pflag ? setfile(from_stat, -1) : 0);
344 }
345
346 int
347 copy_special(struct stat *from_stat, int exists)
348 {
349
350 if (exists && nflag) {
351 if (vflag)
352 printf("%s not overwritten\n", to.p_path);
353 return (1);
354 }
355 if (exists && unlink(to.p_path)) {
356 warn("unlink: %s", to.p_path);
357 return (1);
358 }
359 if (mknod(to.p_path, from_stat->st_mode, from_stat->st_rdev)) {
360 warn("mknod: %s", to.p_path);
361 return (1);
362 }
363 return (pflag ? setfile(from_stat, -1) : 0);
364 }
365
366 int
367 setfile(struct stat *fs, int fd)
368 {
369 static struct timespec tspec[2];
370 struct stat ts;
371 int rval, gotstat, islink, fdval;
372
373 rval = 0;
374 fdval = fd != -1;
375 islink = !fdval && S_ISLNK(fs->st_mode);
376 fs->st_mode &= S_ISUID | S_ISGID | S_ISVTX |
377 S_IRWXU | S_IRWXG | S_IRWXO;
378
379 tspec[0] = fs->st_atim;
380 tspec[1] = fs->st_mtim;
381 if (fdval ? futimens(fd, tspec) : utimensat(AT_FDCWD, to.p_path, tspec,
382 islink ? AT_SYMLINK_NOFOLLOW : 0)) {
383 warn("utimensat: %s", to.p_path);
384 rval = 1;
385 }
386 if (fdval ? fstat(fd, &ts) :
387 (islink ? lstat(to.p_path, &ts) : stat(to.p_path, &ts)))
388 gotstat = 0;
389 else {
390 gotstat = 1;
391 ts.st_mode &= S_ISUID | S_ISGID | S_ISVTX |
392 S_IRWXU | S_IRWXG | S_IRWXO;
393 }
394 /*
395 * Changing the ownership probably won't succeed, unless we're root
396 * or POSIX_CHOWN_RESTRICTED is not set. Set uid/gid before setting
397 * the mode; current BSD behavior is to remove all setuid bits on
398 * chown. If chown fails, lose setuid/setgid bits.
399 */
400 if (!gotstat || fs->st_uid != ts.st_uid || fs->st_gid != ts.st_gid)
401 if (fdval ? fchown(fd, fs->st_uid, fs->st_gid) :
402 (islink ? lchown(to.p_path, fs->st_uid, fs->st_gid) :
403 chown(to.p_path, fs->st_uid, fs->st_gid))) {
404 if (errno != EPERM) {
405 warn("chown: %s", to.p_path);
406 rval = 1;
407 }
408 fs->st_mode &= ~(S_ISUID | S_ISGID);
409 }
410
411 if (!gotstat || fs->st_mode != ts.st_mode)
412 if (fdval ? fchmod(fd, fs->st_mode) :
413 (islink ? lchmod(to.p_path, fs->st_mode) :
414 chmod(to.p_path, fs->st_mode))) {
415 warn("chmod: %s", to.p_path);
416 rval = 1;
417 }
418
419 if (!gotstat || fs->st_flags != ts.st_flags)
420 if (fdval ?
421 fchflags(fd, fs->st_flags) :
422 (islink ? lchflags(to.p_path, fs->st_flags) :
423 chflags(to.p_path, fs->st_flags))) {
424 warn("chflags: %s", to.p_path);
425 rval = 1;
426 }
427
428 return (rval);
429 }
430
431 int
432 preserve_fd_acls(int source_fd, int dest_fd)
433 {
434 acl_t acl;
435 acl_type_t acl_type;
436 int acl_supported = 0, ret, trivial;
437
438 ret = fpathconf(source_fd, _PC_ACL_NFS4);
439 if (ret > 0 ) {
440 acl_supported = 1;
441 acl_type = ACL_TYPE_NFS4;
442 } else if (ret < 0 && errno != EINVAL) {
443 warn("fpathconf(..., _PC_ACL_NFS4) failed for %s", to.p_path);
444 return (1);
445 }
446 if (acl_supported == 0) {
447 ret = fpathconf(source_fd, _PC_ACL_EXTENDED);
448 if (ret > 0 ) {
449 acl_supported = 1;
450 acl_type = ACL_TYPE_ACCESS;
451 } else if (ret < 0 && errno != EINVAL) {
452 warn("fpathconf(..., _PC_ACL_EXTENDED) failed for %s",
453 to.p_path);
454 return (1);
455 }
456 }
457 if (acl_supported == 0)
458 return (0);
459
460 acl = acl_get_fd_np(source_fd, acl_type);
461 if (acl == NULL) {
462 warn("failed to get acl entries while setting %s", to.p_path);
463 return (1);
464 }
465 if (acl_is_trivial_np(acl, &trivial)) {
466 warn("acl_is_trivial() failed for %s", to.p_path);
467 acl_free(acl);
468 return (1);
469 }
470 if (trivial) {
471 acl_free(acl);
472 return (0);
473 }
474 if (acl_set_fd_np(dest_fd, acl, acl_type) < 0) {
475 warn("failed to set acl entries for %s", to.p_path);
476 acl_free(acl);
477 return (1);
478 }
479 acl_free(acl);
480 return (0);
481 }
482
483 int
484 preserve_dir_acls(struct stat *fs, char *source_dir, char *dest_dir)
485 {
486 acl_t (*aclgetf)(const char *, acl_type_t);
487 int (*aclsetf)(const char *, acl_type_t, acl_t);
488 struct acl *aclp;
489 acl_t acl;
490 acl_type_t acl_type;
491 int acl_supported = 0, ret, trivial;
492
493 ret = pathconf(source_dir, _PC_ACL_NFS4);
494 if (ret > 0) {
495 acl_supported = 1;
496 acl_type = ACL_TYPE_NFS4;
497 } else if (ret < 0 && errno != EINVAL) {
498 warn("fpathconf(..., _PC_ACL_NFS4) failed for %s", source_dir);
499 return (1);
500 }
501 if (acl_supported == 0) {
502 ret = pathconf(source_dir, _PC_ACL_EXTENDED);
503 if (ret > 0) {
504 acl_supported = 1;
505 acl_type = ACL_TYPE_ACCESS;
506 } else if (ret < 0 && errno != EINVAL) {
507 warn("fpathconf(..., _PC_ACL_EXTENDED) failed for %s",
508 source_dir);
509 return (1);
510 }
511 }
512 if (acl_supported == 0)
513 return (0);
514
515 /*
516 * If the file is a link we will not follow it.
517 */
518 if (S_ISLNK(fs->st_mode)) {
519 aclgetf = acl_get_link_np;
520 aclsetf = acl_set_link_np;
521 } else {
522 aclgetf = acl_get_file;
523 aclsetf = acl_set_file;
524 }
525 if (acl_type == ACL_TYPE_ACCESS) {
526 /*
527 * Even if there is no ACL_TYPE_DEFAULT entry here, a zero
528 * size ACL will be returned. So it is not safe to simply
529 * check the pointer to see if the default ACL is present.
530 */
531 acl = aclgetf(source_dir, ACL_TYPE_DEFAULT);
532 if (acl == NULL) {
533 warn("failed to get default acl entries on %s",
534 source_dir);
535 return (1);
536 }
537 aclp = &acl->ats_acl;
538 if (aclp->acl_cnt != 0 && aclsetf(dest_dir,
539 ACL_TYPE_DEFAULT, acl) < 0) {
540 warn("failed to set default acl entries on %s",
541 dest_dir);
542 acl_free(acl);
543 return (1);
544 }
545 acl_free(acl);
546 }
547 acl = aclgetf(source_dir, acl_type);
548 if (acl == NULL) {
549 warn("failed to get acl entries on %s", source_dir);
550 return (1);
551 }
552 if (acl_is_trivial_np(acl, &trivial)) {
553 warn("acl_is_trivial() failed on %s", source_dir);
554 acl_free(acl);
555 return (1);
556 }
557 if (trivial) {
558 acl_free(acl);
559 return (0);
560 }
561 if (aclsetf(dest_dir, acl_type, acl) < 0) {
562 warn("failed to set acl entries on %s", dest_dir);
563 acl_free(acl);
564 return (1);
565 }
566 acl_free(acl);
567 return (0);
568 }
569
570 void
571 usage(void)
572 {
573
574 (void)fprintf(stderr, "%s\n%s\n",
575 "usage: cp [-R [-H | -L | -P]] [-f | -i | -n] [-alpsvx] "
576 "source_file target_file",
577 " cp [-R [-H | -L | -P]] [-f | -i | -n] [-alpsvx] "
578 "source_file ... "
579 "target_directory");
580 exit(EX_USAGE);
581 }

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