directory-handle: print `errno` reason on `unlinkat()` error
[lttng-tools.git] / src / common / compat / directory-handle.c
1 /*
2 * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
3 *
4 * SPDX-License-Identifier: GPL-2.0-only
5 *
6 */
7
8 #include <common/compat/directory-handle.h>
9 #include <common/error.h>
10 #include <common/macros.h>
11 #include <common/runas.h>
12 #include <common/credentials.h>
13 #include <lttng/constant.h>
14 #include <common/dynamic-array.h>
15
16 #include <assert.h>
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <fcntl.h>
20 #include <unistd.h>
21 #include <dirent.h>
22
23 /*
24 * This compatibility layer shares a common "base" that is implemented
25 * in terms of an internal API. This file contains two implementations
26 * of the internal API below.
27 */
28 static
29 int lttng_directory_handle_mkdir(
30 const struct lttng_directory_handle *handle,
31 const char *path, mode_t mode);
32 static
33 int _run_as_mkdir(const struct lttng_directory_handle *handle, const char *path,
34 mode_t mode, uid_t uid, gid_t gid);
35 static
36 int _run_as_mkdir_recursive(const struct lttng_directory_handle *handle,
37 const char *path, mode_t mode, uid_t uid, gid_t gid);
38 static
39 int lttng_directory_handle_open(const struct lttng_directory_handle *handle,
40 const char *filename, int flags, mode_t mode);
41 static
42 int _run_as_open(const struct lttng_directory_handle *handle,
43 const char *filename,
44 int flags, mode_t mode, uid_t uid, gid_t gid);
45 static
46 int lttng_directory_handle_unlink(
47 const struct lttng_directory_handle *handle,
48 const char *filename);
49 static
50 int _run_as_unlink(const struct lttng_directory_handle *handle,
51 const char *filename, uid_t uid, gid_t gid);
52 static
53 int _lttng_directory_handle_rename(
54 const struct lttng_directory_handle *old_handle,
55 const char *old_name,
56 const struct lttng_directory_handle *new_handle,
57 const char *new_name);
58 static
59 int _run_as_rename(const struct lttng_directory_handle *old_handle,
60 const char *old_name,
61 const struct lttng_directory_handle *new_handle,
62 const char *new_name, uid_t uid, gid_t gid);
63 static
64 DIR *lttng_directory_handle_opendir(const struct lttng_directory_handle *handle,
65 const char *path);
66 static
67 int lttng_directory_handle_rmdir(
68 const struct lttng_directory_handle *handle, const char *name);
69 static
70 int _run_as_rmdir(const struct lttng_directory_handle *handle,
71 const char *name, uid_t uid, gid_t gid);
72 static
73 int _run_as_rmdir_recursive(
74 const struct lttng_directory_handle *handle, const char *name,
75 uid_t uid, gid_t gid, int flags);
76 static
77 void lttng_directory_handle_invalidate(struct lttng_directory_handle *handle);
78 static
79 void lttng_directory_handle_release(struct urcu_ref *ref);
80
81 #ifdef COMPAT_DIRFD
82
83 /*
84 * Special inode number reserved to represent the "current working directory".
85 * ino_t is spec'ed as being an unsigned integral type.
86 */
87 #define RESERVED_AT_FDCWD_INO \
88 ({ \
89 uint64_t reserved_val; \
90 switch (sizeof(ino_t)) { \
91 case 4: \
92 reserved_val = UINT32_MAX; \
93 break; \
94 case 8: \
95 reserved_val = UINT64_MAX; \
96 break; \
97 default: \
98 abort(); \
99 } \
100 (ino_t) reserved_val; \
101 })
102
103 LTTNG_HIDDEN
104 struct lttng_directory_handle *lttng_directory_handle_create(const char *path)
105 {
106 const struct lttng_directory_handle cwd_handle = {
107 .dirfd = AT_FDCWD,
108 };
109
110 /* Open a handle to the CWD if NULL is passed. */
111 return lttng_directory_handle_create_from_handle(path, &cwd_handle);
112 }
113
114 LTTNG_HIDDEN
115 struct lttng_directory_handle *lttng_directory_handle_create_from_handle(
116 const char *path,
117 const struct lttng_directory_handle *ref_handle)
118 {
119 int dirfd;
120 struct lttng_directory_handle *handle = NULL;
121
122 if (!path) {
123 handle = lttng_directory_handle_copy(ref_handle);
124 goto end;
125 }
126 if (!*path) {
127 ERR("Failed to initialize directory handle: provided path is an empty string");
128 goto end;
129 }
130
131 dirfd = openat(ref_handle->dirfd, path, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
132 if (dirfd == -1) {
133 PERROR("Failed to initialize directory handle to \"%s\"", path);
134 goto end;
135 }
136
137 handle = lttng_directory_handle_create_from_dirfd(dirfd);
138 if (!handle) {
139 goto error_close;
140 }
141 end:
142 return handle;
143 error_close:
144 if (close(dirfd)) {
145 PERROR("Failed to close directory file descriptor");
146 }
147 return NULL;
148 }
149
150 LTTNG_HIDDEN
151 struct lttng_directory_handle *lttng_directory_handle_create_from_dirfd(
152 int dirfd)
153 {
154 int ret;
155 struct lttng_directory_handle *handle = zmalloc(sizeof(*handle));
156 struct stat stat_buf;
157
158 if (!handle) {
159 goto end;
160 }
161
162 if (dirfd != AT_FDCWD) {
163 ret = fstat(dirfd, &stat_buf);
164 if (ret) {
165 PERROR("Failed to fstat directory file descriptor %i", dirfd);
166 lttng_directory_handle_release(&handle->ref);
167 handle = NULL;
168 goto end;
169 }
170 } else {
171 handle->directory_inode = RESERVED_AT_FDCWD_INO;
172 }
173 handle->dirfd = dirfd;
174 urcu_ref_init(&handle->ref);
175 end:
176 return handle;
177 }
178
179 static
180 void lttng_directory_handle_release(struct urcu_ref *ref)
181 {
182 int ret;
183 struct lttng_directory_handle *handle =
184 container_of(ref, struct lttng_directory_handle, ref);
185
186 if (handle->destroy_cb) {
187 handle->destroy_cb(handle, handle->destroy_cb_data);
188 }
189
190 if (handle->dirfd == AT_FDCWD || handle->dirfd == -1) {
191 goto end;
192 }
193 ret = close(handle->dirfd);
194 if (ret == -1) {
195 PERROR("Failed to close directory file descriptor of directory handle");
196 }
197 end:
198 lttng_directory_handle_invalidate(handle);
199 free(handle);
200 }
201
202 LTTNG_HIDDEN
203 struct lttng_directory_handle *lttng_directory_handle_copy(
204 const struct lttng_directory_handle *handle)
205 {
206 struct lttng_directory_handle *new_handle = NULL;
207
208 if (handle->dirfd == AT_FDCWD) {
209 new_handle = lttng_directory_handle_create_from_dirfd(AT_FDCWD);
210 } else {
211 const int new_dirfd = dup(handle->dirfd);
212
213 if (new_dirfd == -1) {
214 PERROR("Failed to duplicate directory file descriptor of directory handle");
215 goto end;
216 }
217 new_handle = lttng_directory_handle_create_from_dirfd(
218 new_dirfd);
219 if (!new_handle && close(new_dirfd)) {
220 PERROR("Failed to close directory file descriptor of directory handle");
221 }
222 }
223 end:
224 return new_handle;
225 }
226
227 LTTNG_HIDDEN
228 bool lttng_directory_handle_equals(const struct lttng_directory_handle *lhs,
229 const struct lttng_directory_handle *rhs)
230 {
231 return lhs->directory_inode == rhs->directory_inode;
232 }
233
234 static
235 void lttng_directory_handle_invalidate(struct lttng_directory_handle *handle)
236 {
237 handle->dirfd = -1;
238 }
239
240 LTTNG_HIDDEN
241 int lttng_directory_handle_stat(const struct lttng_directory_handle *handle,
242 const char *path, struct stat *st)
243 {
244 return fstatat(handle->dirfd, path, st, 0);
245 }
246
247 LTTNG_HIDDEN
248 bool lttng_directory_handle_uses_fd(
249 const struct lttng_directory_handle *handle)
250 {
251 return handle->dirfd != AT_FDCWD;
252 }
253
254 static
255 int lttng_directory_handle_mkdir(
256 const struct lttng_directory_handle *handle,
257 const char *path, mode_t mode)
258 {
259 return mkdirat(handle->dirfd, path, mode);
260 }
261
262 static
263 int lttng_directory_handle_open(const struct lttng_directory_handle *handle,
264 const char *filename, int flags, mode_t mode)
265 {
266 return openat(handle->dirfd, filename, flags, mode);
267 }
268
269 static
270 int _run_as_open(const struct lttng_directory_handle *handle,
271 const char *filename,
272 int flags, mode_t mode, uid_t uid, gid_t gid)
273 {
274 return run_as_openat(handle->dirfd, filename, flags, mode, uid, gid);
275 }
276
277 static
278 int _run_as_unlink(const struct lttng_directory_handle *handle,
279 const char *filename, uid_t uid, gid_t gid)
280 {
281 return run_as_unlinkat(handle->dirfd, filename, uid, gid);
282 }
283
284 static
285 int lttng_directory_handle_unlink(
286 const struct lttng_directory_handle *handle,
287 const char *filename)
288 {
289 return unlinkat(handle->dirfd, filename, 0);
290 }
291
292 static
293 int _run_as_mkdir(const struct lttng_directory_handle *handle,
294 const char *path, mode_t mode, uid_t uid, gid_t gid)
295 {
296 return run_as_mkdirat(handle->dirfd, path, mode, uid, gid);
297 }
298
299 static
300 int _run_as_mkdir_recursive(const struct lttng_directory_handle *handle,
301 const char *path, mode_t mode, uid_t uid, gid_t gid)
302 {
303 return run_as_mkdirat_recursive(handle->dirfd, path, mode, uid, gid);
304 }
305
306 static
307 int _lttng_directory_handle_rename(
308 const struct lttng_directory_handle *old_handle,
309 const char *old_name,
310 const struct lttng_directory_handle *new_handle,
311 const char *new_name)
312 {
313 return renameat(old_handle->dirfd, old_name,
314 new_handle->dirfd, new_name);
315 }
316
317 static
318 int _run_as_rename(const struct lttng_directory_handle *old_handle,
319 const char *old_name,
320 const struct lttng_directory_handle *new_handle,
321 const char *new_name, uid_t uid, gid_t gid)
322 {
323 return run_as_renameat(old_handle->dirfd, old_name, new_handle->dirfd,
324 new_name, uid, gid);
325 }
326
327 static
328 DIR *lttng_directory_handle_opendir(const struct lttng_directory_handle *handle,
329 const char *path)
330 {
331 DIR *dir_stream = NULL;
332 int fd = openat(handle->dirfd, path, O_RDONLY);
333
334 if (fd < 0) {
335 goto end;
336 }
337
338 dir_stream = fdopendir(fd);
339 if (!dir_stream) {
340 int ret;
341
342 PERROR("Failed to open directory stream");
343 ret = close(fd);
344 if (ret) {
345 PERROR("Failed to close file descriptor to %s", path);
346 }
347 goto end;
348 }
349
350 end:
351 return dir_stream;
352 }
353
354 static
355 int lttng_directory_handle_rmdir(
356 const struct lttng_directory_handle *handle, const char *name)
357 {
358 int ret = unlinkat(handle->dirfd, name, AT_REMOVEDIR);
359 if (ret) {
360 PERROR("Failed to remove directory `%s`", name);
361 }
362
363 return ret;
364 }
365
366 static
367 int _run_as_rmdir(const struct lttng_directory_handle *handle,
368 const char *name, uid_t uid, gid_t gid)
369 {
370 return run_as_rmdirat(handle->dirfd, name, uid, gid);
371 }
372
373 static
374 int _run_as_rmdir_recursive(
375 const struct lttng_directory_handle *handle, const char *name,
376 uid_t uid, gid_t gid, int flags)
377 {
378 return run_as_rmdirat_recursive(handle->dirfd, name, uid, gid, flags);
379 }
380
381 #else /* COMPAT_DIRFD */
382
383 static
384 int get_full_path(const struct lttng_directory_handle *handle,
385 const char *subdirectory, char *fullpath, size_t size)
386 {
387 int ret;
388 const bool subdirectory_is_absolute =
389 subdirectory && *subdirectory == '/';
390 const char * const base = subdirectory_is_absolute ?
391 subdirectory : handle->base_path;
392 const char * const end = subdirectory && !subdirectory_is_absolute ?
393 subdirectory : NULL;
394 const size_t base_len = strlen(base);
395 const size_t end_len = end ? strlen(end) : 0;
396 const bool add_separator_slash = end && base[base_len - 1] != '/';
397 const bool add_trailing_slash = end && end[end_len - 1] != '/';
398
399 ret = snprintf(fullpath, size, "%s%s%s%s",
400 base,
401 add_separator_slash ? "/" : "",
402 end ? end : "",
403 add_trailing_slash ? "/" : "");
404 if (ret == -1 || ret >= size) {
405 ERR("Failed to format subdirectory from directory handle");
406 ret = -1;
407 goto end;
408 }
409 ret = 0;
410 end:
411 return ret;
412 }
413
414 static
415 struct lttng_directory_handle *_lttng_directory_handle_create(char *path)
416 {
417 struct lttng_directory_handle *handle = zmalloc(sizeof(*handle));
418
419 if (!handle) {
420 goto end;
421 }
422 urcu_ref_init(&handle->ref);
423 handle->base_path = path;
424 end:
425 return handle;
426 }
427
428 LTTNG_HIDDEN
429 struct lttng_directory_handle *lttng_directory_handle_create(
430 const char *path)
431 {
432 int ret;
433 const char *cwd = "";
434 size_t cwd_len, path_len;
435 char cwd_buf[LTTNG_PATH_MAX] = {};
436 char handle_buf[LTTNG_PATH_MAX] = {};
437 struct lttng_directory_handle *new_handle = NULL;
438 bool add_cwd_slash = false, add_trailing_slash = false;
439 const struct lttng_directory_handle cwd_handle = {
440 .base_path = handle_buf,
441 };
442
443 path_len = path ? strlen(path) : 0;
444 add_trailing_slash = path && path[path_len - 1] != '/';
445 if (!path || (path && *path != '/')) {
446 cwd = getcwd(cwd_buf, sizeof(cwd_buf));
447 if (!cwd) {
448 PERROR("Failed to initialize directory handle, can't get current working directory");
449 ret = -1;
450 goto end;
451 }
452 cwd_len = strlen(cwd);
453 if (cwd_len == 0) {
454 ERR("Failed to initialize directory handle, current working directory path has a length of 0");
455 ret = -1;
456 goto end;
457 }
458 add_cwd_slash = cwd[cwd_len - 1] != '/';
459 }
460
461 ret = snprintf(handle_buf, sizeof(handle_buf), "%s%s%s%s",
462 cwd,
463 add_cwd_slash ? "/" : "",
464 path ? : "",
465 add_trailing_slash ? "/" : "");
466 if (ret == -1 || ret >= LTTNG_PATH_MAX) {
467 ERR("Failed to initialize directory handle, failed to format directory path");
468 goto end;
469 }
470
471 new_handle = lttng_directory_handle_create_from_handle(path, &cwd_handle);
472 end:
473 return new_handle;
474 }
475
476 LTTNG_HIDDEN
477 struct lttng_directory_handle *lttng_directory_handle_create_from_handle(
478 const char *path,
479 const struct lttng_directory_handle *ref_handle)
480 {
481 int ret;
482 size_t path_len, handle_path_len;
483 bool add_trailing_slash;
484 struct stat stat_buf;
485 struct lttng_directory_handle *new_handle = NULL;
486 char *new_path = NULL;
487
488 assert(ref_handle && ref_handle->base_path);
489
490 ret = lttng_directory_handle_stat(ref_handle, path, &stat_buf);
491 if (ret == -1) {
492 PERROR("Failed to create directory handle");
493 goto end;
494 } else if (!S_ISDIR(stat_buf.st_mode)) {
495 char full_path[LTTNG_PATH_MAX];
496
497 /* Best effort for logging purposes. */
498 ret = get_full_path(ref_handle, path, full_path,
499 sizeof(full_path));
500 if (ret) {
501 full_path[0] = '\0';
502 }
503
504 ERR("Failed to initialize directory handle to \"%s\": not a directory",
505 full_path);
506 goto end;
507 }
508 if (!path) {
509 new_handle = lttng_directory_handle_copy(ref_handle);
510 goto end;
511 }
512
513 path_len = strlen(path);
514 if (path_len == 0) {
515 ERR("Failed to initialize directory handle: provided path is an empty string");
516 ret = -1;
517 goto end;
518 }
519 if (*path == '/') {
520 new_path = strdup(path);
521 if (!new_path) {
522 goto end;
523 }
524 /* Takes ownership of new_path. */
525 new_handle = _lttng_directory_handle_create(new_path);
526 new_path = NULL;
527 goto end;
528 }
529
530 add_trailing_slash = path[path_len - 1] != '/';
531
532 handle_path_len = strlen(ref_handle->base_path) + path_len +
533 !!add_trailing_slash;
534 if (handle_path_len >= LTTNG_PATH_MAX) {
535 ERR("Failed to initialize directory handle as the resulting path's length (%zu bytes) exceeds the maximal allowed length (%d bytes)",
536 handle_path_len, LTTNG_PATH_MAX);
537 goto end;
538 }
539 new_path = zmalloc(handle_path_len);
540 if (!new_path) {
541 PERROR("Failed to initialize directory handle");
542 goto end;
543 }
544
545 ret = sprintf(new_handle->base_path, "%s%s%s",
546 ref_handle->base_path,
547 path,
548 add_trailing_slash ? "/" : "");
549 if (ret == -1 || ret >= handle_path_len) {
550 ERR("Failed to initialize directory handle: path formatting failed");
551 goto end;
552 }
553 new_handle = _lttng_directory_handle_create(new_path);
554 new_path = NULL;
555 end:
556 free(new_path);
557 return new_handle;
558 }
559
560 LTTNG_HIDDEN
561 struct lttng_directory_handle *lttng_directory_handle_create_from_dirfd(
562 int dirfd)
563 {
564 assert(dirfd == AT_FDCWD);
565 return lttng_directory_handle_create(NULL);
566 }
567
568 static
569 void lttng_directory_handle_release(struct urcu_ref *ref)
570 {
571 struct lttng_directory_handle *handle =
572 container_of(ref, struct lttng_directory_handle, ref);
573
574 free(handle->base_path);
575 lttng_directory_handle_invalidate(handle);
576 free(handle);
577 }
578
579 LTTNG_HIDDEN
580 struct lttng_directory_handle *lttng_directory_handle_copy(
581 const struct lttng_directory_handle *handle)
582 {
583 struct lttng_directory_handle *new_handle = NULL;
584 char *new_path = NULL;
585
586 if (handle->base_path) {
587 new_path = strdup(handle->base_path);
588 if (!new_path) {
589 goto end;
590 }
591 }
592 new_handle = _lttng_directory_handle_create(new_path);
593 end:
594 return new_handle;
595 }
596
597 LTTNG_HIDDEN
598 bool lttng_directory_handle_equals(const struct lttng_directory_handle *lhs,
599 const struct lttng_directory_handle *rhs)
600 {
601 return strcmp(lhs->base_path, rhs->base_path) == 0;
602 }
603
604 static
605 void lttng_directory_handle_invalidate(struct lttng_directory_handle *handle)
606 {
607 handle->base_path = NULL;
608 }
609
610 LTTNG_HIDDEN
611 int lttng_directory_handle_stat(const struct lttng_directory_handle *handle,
612 const char *subdirectory, struct stat *st)
613 {
614 int ret;
615 char fullpath[LTTNG_PATH_MAX];
616
617 ret = get_full_path(handle, subdirectory, fullpath, sizeof(fullpath));
618 if (ret) {
619 errno = ENOMEM;
620 goto end;
621 }
622
623 ret = stat(fullpath, st);
624 end:
625 return ret;
626 }
627
628 LTTNG_HIDDEN
629 bool lttng_directory_handle_uses_fd(
630 const struct lttng_directory_handle *handle)
631 {
632 return false;
633 }
634
635 static
636 int lttng_directory_handle_mkdir(const struct lttng_directory_handle *handle,
637 const char *subdirectory, mode_t mode)
638 {
639 int ret;
640 char fullpath[LTTNG_PATH_MAX];
641
642 ret = get_full_path(handle, subdirectory, fullpath, sizeof(fullpath));
643 if (ret) {
644 errno = ENOMEM;
645 goto end;
646 }
647
648 ret = mkdir(fullpath, mode);
649 end:
650 return ret;
651 }
652
653 static
654 int lttng_directory_handle_open(const struct lttng_directory_handle *handle,
655 const char *filename, int flags, mode_t mode)
656 {
657 int ret;
658 char fullpath[LTTNG_PATH_MAX];
659
660 ret = get_full_path(handle, filename, fullpath, sizeof(fullpath));
661 if (ret) {
662 errno = ENOMEM;
663 goto end;
664 }
665
666 ret = open(fullpath, flags, mode);
667 end:
668 return ret;
669 }
670
671 static
672 int lttng_directory_handle_unlink(
673 const struct lttng_directory_handle *handle,
674 const char *filename)
675 {
676 int ret;
677 char fullpath[LTTNG_PATH_MAX];
678
679 ret = get_full_path(handle, filename, fullpath, sizeof(fullpath));
680 if (ret) {
681 errno = ENOMEM;
682 goto end;
683 }
684
685 ret = unlink(fullpath);
686 end:
687 return ret;
688 }
689
690 static
691 int _run_as_mkdir(const struct lttng_directory_handle *handle, const char *path,
692 mode_t mode, uid_t uid, gid_t gid)
693 {
694 int ret;
695 char fullpath[LTTNG_PATH_MAX];
696
697 ret = get_full_path(handle, path, fullpath, sizeof(fullpath));
698 if (ret) {
699 errno = ENOMEM;
700 goto end;
701 }
702
703 ret = run_as_mkdir(fullpath, mode, uid, gid);
704 end:
705 return ret;
706 }
707
708 static
709 int _run_as_open(const struct lttng_directory_handle *handle,
710 const char *filename,
711 int flags, mode_t mode, uid_t uid, gid_t gid)
712 {
713 int ret;
714 char fullpath[LTTNG_PATH_MAX];
715
716 ret = get_full_path(handle, filename, fullpath, sizeof(fullpath));
717 if (ret) {
718 errno = ENOMEM;
719 goto end;
720 }
721
722 ret = run_as_open(fullpath, flags, mode, uid, gid);
723 end:
724 return ret;
725 }
726
727 static
728 int _run_as_unlink(const struct lttng_directory_handle *handle,
729 const char *filename, uid_t uid, gid_t gid)
730 {
731 int ret;
732 char fullpath[LTTNG_PATH_MAX];
733
734 ret = get_full_path(handle, filename, fullpath, sizeof(fullpath));
735 if (ret) {
736 errno = ENOMEM;
737 goto end;
738 }
739
740 ret = run_as_unlink(fullpath, uid, gid);
741 end:
742 return ret;
743 }
744
745 static
746 int _run_as_mkdir_recursive(const struct lttng_directory_handle *handle,
747 const char *path, mode_t mode, uid_t uid, gid_t gid)
748 {
749 int ret;
750 char fullpath[LTTNG_PATH_MAX];
751
752 ret = get_full_path(handle, path, fullpath, sizeof(fullpath));
753 if (ret) {
754 errno = ENOMEM;
755 goto end;
756 }
757
758 ret = run_as_mkdir_recursive(fullpath, mode, uid, gid);
759 end:
760 return ret;
761 }
762
763 static
764 int _lttng_directory_handle_rename(
765 const struct lttng_directory_handle *old_handle,
766 const char *old_name,
767 const struct lttng_directory_handle *new_handle,
768 const char *new_name)
769 {
770 int ret;
771 char old_fullpath[LTTNG_PATH_MAX];
772 char new_fullpath[LTTNG_PATH_MAX];
773
774 ret = get_full_path(old_handle, old_name, old_fullpath,
775 sizeof(old_fullpath));
776 if (ret) {
777 errno = ENOMEM;
778 goto end;
779 }
780 ret = get_full_path(new_handle, new_name, new_fullpath,
781 sizeof(new_fullpath));
782 if (ret) {
783 errno = ENOMEM;
784 goto end;
785 }
786
787 ret = rename(old_fullpath, new_fullpath);
788 end:
789 return ret;
790 }
791
792 static
793 int _run_as_rename(const struct lttng_directory_handle *old_handle,
794 const char *old_name,
795 const struct lttng_directory_handle *new_handle,
796 const char *new_name, uid_t uid, gid_t gid)
797 {
798 int ret;
799 char old_fullpath[LTTNG_PATH_MAX];
800 char new_fullpath[LTTNG_PATH_MAX];
801
802 ret = get_full_path(old_handle, old_name, old_fullpath,
803 sizeof(old_fullpath));
804 if (ret) {
805 errno = ENOMEM;
806 goto end;
807 }
808 ret = get_full_path(new_handle, new_name, new_fullpath,
809 sizeof(new_fullpath));
810 if (ret) {
811 errno = ENOMEM;
812 goto end;
813 }
814
815 ret = run_as_rename(old_fullpath, new_fullpath, uid, gid);
816 end:
817 return ret;
818 }
819
820 static
821 DIR *lttng_directory_handle_opendir(const struct lttng_directory_handle *handle,
822 const char *path)
823 {
824 int ret;
825 DIR *dir_stream = NULL;
826 char fullpath[LTTNG_PATH_MAX];
827
828 ret = get_full_path(handle, path, fullpath, sizeof(fullpath));
829 if (ret) {
830 errno = ENOMEM;
831 goto end;
832 }
833
834 dir_stream = opendir(fullpath);
835 end:
836 return dir_stream;
837 }
838
839 static
840 int lttng_directory_handle_rmdir(
841 const struct lttng_directory_handle *handle, const char *name)
842 {
843 int ret;
844 char fullpath[LTTNG_PATH_MAX];
845
846 ret = get_full_path(handle, name, fullpath, sizeof(fullpath));
847 if (ret) {
848 errno = ENOMEM;
849 goto end;
850 }
851
852 ret = rmdir(fullpath);
853 end:
854 return ret;
855 }
856
857 static
858 int _run_as_rmdir(const struct lttng_directory_handle *handle,
859 const char *name, uid_t uid, gid_t gid)
860 {
861 int ret;
862 char fullpath[LTTNG_PATH_MAX];
863
864 ret = get_full_path(handle, name, fullpath, sizeof(fullpath));
865 if (ret) {
866 errno = ENOMEM;
867 goto end;
868 }
869
870 ret = run_as_rmdir(fullpath, uid, gid);
871 end:
872 return ret;
873 }
874
875 static
876 int _run_as_rmdir_recursive(
877 const struct lttng_directory_handle *handle, const char *name,
878 uid_t uid, gid_t gid, int flags)
879 {
880 int ret;
881 char fullpath[LTTNG_PATH_MAX];
882
883 ret = get_full_path(handle, name, fullpath, sizeof(fullpath));
884 if (ret) {
885 errno = ENOMEM;
886 goto end;
887 }
888
889 ret = run_as_rmdir_recursive(fullpath, uid, gid, flags);
890 end:
891 return ret;
892 }
893
894 #endif /* COMPAT_DIRFD */
895
896 /* Common implementation. */
897
898 /*
899 * On some filesystems (e.g. nfs), mkdir will validate access rights before
900 * checking for the existence of the path element. This means that on a setup
901 * where "/home/" is a mounted NFS share, and running as an unpriviledged user,
902 * recursively creating a path of the form "/home/my_user/trace/" will fail with
903 * EACCES on mkdir("/home", ...).
904 *
905 * Checking the path for existence allows us to work around this behaviour.
906 */
907 static
908 int create_directory_check_exists(const struct lttng_directory_handle *handle,
909 const char *path, mode_t mode)
910 {
911 int ret = 0;
912 struct stat st;
913
914 ret = lttng_directory_handle_stat(handle, path, &st);
915 if (ret == 0) {
916 if (S_ISDIR(st.st_mode)) {
917 /* Directory exists, skip. */
918 goto end;
919 } else {
920 /* Exists, but is not a directory. */
921 errno = ENOTDIR;
922 ret = -1;
923 goto end;
924 }
925 } else if (errno != ENOENT) {
926 goto end;
927 }
928
929 /*
930 * Let mkdir handle other errors as the caller expects mkdir
931 * semantics.
932 */
933 ret = lttng_directory_handle_mkdir(handle, path, mode);
934 end:
935 return ret;
936 }
937
938 static
939 int create_directory_recursive(const struct lttng_directory_handle *handle,
940 const char *path, mode_t mode)
941 {
942 char *p, tmp[LTTNG_PATH_MAX];
943 size_t len;
944 int ret;
945
946 assert(path);
947
948 ret = lttng_strncpy(tmp, path, sizeof(tmp));
949 if (ret) {
950 ERR("Failed to create directory: provided path's length (%zu bytes) exceeds the maximal allowed length (%zu bytes)",
951 strlen(path) + 1, sizeof(tmp));
952 goto error;
953 }
954
955 len = strlen(path);
956 if (tmp[len - 1] == '/') {
957 tmp[len - 1] = 0;
958 }
959
960 for (p = tmp + 1; *p; p++) {
961 if (*p == '/') {
962 *p = 0;
963 if (tmp[strlen(tmp) - 1] == '.' &&
964 tmp[strlen(tmp) - 2] == '.' &&
965 tmp[strlen(tmp) - 3] == '/') {
966 ERR("Using '/../' is not permitted in the trace path (%s)",
967 tmp);
968 ret = -1;
969 goto error;
970 }
971 ret = create_directory_check_exists(handle, tmp, mode);
972 if (ret < 0) {
973 if (errno != EACCES) {
974 PERROR("Failed to create directory \"%s\"",
975 path);
976 ret = -errno;
977 goto error;
978 }
979 }
980 *p = '/';
981 }
982 }
983
984 ret = create_directory_check_exists(handle, tmp, mode);
985 if (ret < 0) {
986 PERROR("mkdirat recursive last element");
987 ret = -errno;
988 }
989 error:
990 return ret;
991 }
992
993 LTTNG_HIDDEN
994 bool lttng_directory_handle_get(struct lttng_directory_handle *handle)
995 {
996 return urcu_ref_get_unless_zero(&handle->ref);
997 }
998
999 LTTNG_HIDDEN
1000 void lttng_directory_handle_put(struct lttng_directory_handle *handle)
1001 {
1002 if (!handle) {
1003 return;
1004 }
1005 assert(handle->ref.refcount);
1006 urcu_ref_put(&handle->ref, lttng_directory_handle_release);
1007 }
1008
1009 LTTNG_HIDDEN
1010 int lttng_directory_handle_create_subdirectory_as_user(
1011 const struct lttng_directory_handle *handle,
1012 const char *subdirectory,
1013 mode_t mode, const struct lttng_credentials *creds)
1014 {
1015 int ret;
1016
1017 if (!creds) {
1018 /* Run as current user. */
1019 ret = create_directory_check_exists(handle,
1020 subdirectory, mode);
1021 } else {
1022 ret = _run_as_mkdir(handle, subdirectory,
1023 mode, creds->uid, creds->gid);
1024 }
1025
1026 return ret;
1027 }
1028
1029 LTTNG_HIDDEN
1030 int lttng_directory_handle_create_subdirectory_recursive_as_user(
1031 const struct lttng_directory_handle *handle,
1032 const char *subdirectory_path,
1033 mode_t mode, const struct lttng_credentials *creds)
1034 {
1035 int ret;
1036
1037 if (!creds) {
1038 /* Run as current user. */
1039 ret = create_directory_recursive(handle,
1040 subdirectory_path, mode);
1041 } else {
1042 ret = _run_as_mkdir_recursive(handle, subdirectory_path,
1043 mode, creds->uid, creds->gid);
1044 }
1045
1046 return ret;
1047 }
1048
1049 LTTNG_HIDDEN
1050 int lttng_directory_handle_create_subdirectory(
1051 const struct lttng_directory_handle *handle,
1052 const char *subdirectory,
1053 mode_t mode)
1054 {
1055 return lttng_directory_handle_create_subdirectory_as_user(
1056 handle, subdirectory, mode, NULL);
1057 }
1058
1059 LTTNG_HIDDEN
1060 int lttng_directory_handle_create_subdirectory_recursive(
1061 const struct lttng_directory_handle *handle,
1062 const char *subdirectory_path,
1063 mode_t mode)
1064 {
1065 return lttng_directory_handle_create_subdirectory_recursive_as_user(
1066 handle, subdirectory_path, mode, NULL);
1067 }
1068
1069 LTTNG_HIDDEN
1070 int lttng_directory_handle_open_file_as_user(
1071 const struct lttng_directory_handle *handle,
1072 const char *filename,
1073 int flags, mode_t mode,
1074 const struct lttng_credentials *creds)
1075 {
1076 int ret;
1077
1078 if (!creds) {
1079 /* Run as current user. */
1080 ret = lttng_directory_handle_open(handle, filename, flags,
1081 mode);
1082 } else {
1083 ret = _run_as_open(handle, filename, flags, mode,
1084 creds->uid, creds->gid);
1085 }
1086 return ret;
1087 }
1088
1089 LTTNG_HIDDEN
1090 int lttng_directory_handle_open_file(
1091 const struct lttng_directory_handle *handle,
1092 const char *filename,
1093 int flags, mode_t mode)
1094 {
1095 return lttng_directory_handle_open_file_as_user(handle, filename, flags,
1096 mode, NULL);
1097 }
1098
1099 LTTNG_HIDDEN
1100 int lttng_directory_handle_unlink_file_as_user(
1101 const struct lttng_directory_handle *handle,
1102 const char *filename,
1103 const struct lttng_credentials *creds)
1104 {
1105 int ret;
1106
1107 if (!creds) {
1108 /* Run as current user. */
1109 ret = lttng_directory_handle_unlink(handle, filename);
1110 } else {
1111 ret = _run_as_unlink(handle, filename, creds->uid, creds->gid);
1112 }
1113 return ret;
1114 }
1115
1116 LTTNG_HIDDEN
1117 int lttng_directory_handle_unlink_file(
1118 const struct lttng_directory_handle *handle,
1119 const char *filename)
1120 {
1121 return lttng_directory_handle_unlink_file_as_user(handle,
1122 filename, NULL);
1123 }
1124
1125 LTTNG_HIDDEN
1126 int lttng_directory_handle_rename(
1127 const struct lttng_directory_handle *old_handle,
1128 const char *old_name,
1129 const struct lttng_directory_handle *new_handle,
1130 const char *new_name)
1131 {
1132 return lttng_directory_handle_rename_as_user(old_handle, old_name,
1133 new_handle, new_name, NULL);
1134 }
1135
1136 LTTNG_HIDDEN
1137 int lttng_directory_handle_rename_as_user(
1138 const struct lttng_directory_handle *old_handle,
1139 const char *old_name,
1140 const struct lttng_directory_handle *new_handle,
1141 const char *new_name,
1142 const struct lttng_credentials *creds)
1143 {
1144 int ret;
1145
1146 if (!creds) {
1147 /* Run as current user. */
1148 ret = _lttng_directory_handle_rename(old_handle,
1149 old_name, new_handle, new_name);
1150 } else {
1151 ret = _run_as_rename(old_handle, old_name, new_handle,
1152 new_name, creds->uid, creds->gid);
1153 }
1154 return ret;
1155 }
1156
1157 LTTNG_HIDDEN
1158 int lttng_directory_handle_remove_subdirectory(
1159 const struct lttng_directory_handle *handle,
1160 const char *name)
1161 {
1162 return lttng_directory_handle_remove_subdirectory_as_user(handle, name,
1163 NULL);
1164 }
1165
1166 LTTNG_HIDDEN
1167 int lttng_directory_handle_remove_subdirectory_as_user(
1168 const struct lttng_directory_handle *handle,
1169 const char *name,
1170 const struct lttng_credentials *creds)
1171 {
1172 int ret;
1173
1174 if (!creds) {
1175 /* Run as current user. */
1176 ret = lttng_directory_handle_rmdir(handle, name);
1177 } else {
1178 ret = _run_as_rmdir(handle, name, creds->uid, creds->gid);
1179 }
1180 return ret;
1181 }
1182
1183 struct rmdir_frame {
1184 ssize_t parent_frame_idx;
1185 DIR *dir;
1186 bool empty;
1187 /* Size including '\0'. */
1188 size_t path_size;
1189 };
1190
1191 static
1192 void rmdir_frame_fini(void *data)
1193 {
1194 int ret;
1195 struct rmdir_frame *frame = data;
1196
1197 ret = closedir(frame->dir);
1198 if (ret == -1) {
1199 PERROR("Failed to close directory stream");
1200 }
1201 }
1202
1203 static
1204 int remove_directory_recursive(const struct lttng_directory_handle *handle,
1205 const char *path, int flags)
1206 {
1207 int ret;
1208 struct lttng_dynamic_array frames;
1209 size_t current_frame_idx = 0;
1210 struct rmdir_frame initial_frame = {
1211 .parent_frame_idx = -1,
1212 .dir = lttng_directory_handle_opendir(handle, path),
1213 .empty = true,
1214 .path_size = strlen(path) + 1,
1215 };
1216 struct lttng_dynamic_buffer current_path;
1217 const char separator = '/';
1218
1219 lttng_dynamic_buffer_init(&current_path);
1220 lttng_dynamic_array_init(&frames, sizeof(struct rmdir_frame),
1221 rmdir_frame_fini);
1222
1223 if (flags & ~(LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG |
1224 LTTNG_DIRECTORY_HANDLE_FAIL_NON_EMPTY_FLAG)) {
1225 ERR("Unknown flags %d", flags);
1226 ret = -1;
1227 goto end;
1228 }
1229
1230 if (!initial_frame.dir) {
1231 if (flags & LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG &&
1232 errno == ENOENT) {
1233 DBG("Cannot rmdir \"%s\": root does not exist", path);
1234 ret = 0;
1235 goto end;
1236 } else {
1237 PERROR("Failed to rmdir \"%s\"", path);
1238 ret = -1;
1239 goto end;
1240 }
1241 }
1242
1243 ret = lttng_dynamic_array_add_element(&frames, &initial_frame);
1244 if (ret) {
1245 ERR("Failed to push context frame during recursive directory removal");
1246 rmdir_frame_fini(&initial_frame);
1247 goto end;
1248 }
1249
1250 ret = lttng_dynamic_buffer_append(
1251 &current_path, path, initial_frame.path_size);
1252 if (ret) {
1253 ERR("Failed to set initial path during recursive directory removal");
1254 ret = -1;
1255 goto end;
1256 }
1257
1258 while (lttng_dynamic_array_get_count(&frames) > 0) {
1259 struct dirent *entry;
1260 struct rmdir_frame *current_frame =
1261 lttng_dynamic_array_get_element(
1262 &frames, current_frame_idx);
1263
1264 assert(current_frame->dir);
1265 ret = lttng_dynamic_buffer_set_size(
1266 &current_path, current_frame->path_size);
1267 assert(!ret);
1268 current_path.data[current_path.size - 1] = '\0';
1269
1270 while ((entry = readdir(current_frame->dir))) {
1271 struct stat st;
1272
1273 if (!strcmp(entry->d_name, ".") ||
1274 !strcmp(entry->d_name, "..")) {
1275 continue;
1276 }
1277
1278 /* Set current_path to the entry's path. */
1279 ret = lttng_dynamic_buffer_set_size(
1280 &current_path, current_path.size - 1);
1281 assert(!ret);
1282 ret = lttng_dynamic_buffer_append(&current_path,
1283 &separator, sizeof(separator));
1284 if (ret) {
1285 goto end;
1286 }
1287 ret = lttng_dynamic_buffer_append(&current_path,
1288 entry->d_name,
1289 strlen(entry->d_name) + 1);
1290 if (ret) {
1291 goto end;
1292 }
1293
1294 if (lttng_directory_handle_stat(
1295 handle, current_path.data, &st)) {
1296 if ((flags & LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG) &&
1297 errno == ENOENT) {
1298 break;
1299 }
1300 PERROR("Failed to stat \"%s\"",
1301 current_path.data);
1302 ret = -1;
1303 goto end;
1304 }
1305
1306 if (!S_ISDIR(st.st_mode)) {
1307 if (flags & LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG) {
1308 current_frame->empty = false;
1309 break;
1310 } else {
1311 /* Not empty, abort. */
1312 DBG("Directory \"%s\" is not empty; refusing to remove directory",
1313 current_path.data);
1314 ret = -1;
1315 goto end;
1316 }
1317 } else {
1318 struct rmdir_frame new_frame = {
1319 .path_size = current_path.size,
1320 .dir = lttng_directory_handle_opendir(
1321 handle,
1322 current_path.data),
1323 .empty = true,
1324 .parent_frame_idx = current_frame_idx,
1325 };
1326
1327 if (!new_frame.dir) {
1328 if (flags & LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG &&
1329 errno == ENOENT) {
1330 DBG("Non-existing directory stream during recursive directory removal");
1331 break;
1332 } else {
1333 PERROR("Failed to open directory stream during recursive directory removal");
1334 ret = -1;
1335 goto end;
1336 }
1337 }
1338 ret = lttng_dynamic_array_add_element(
1339 &frames, &new_frame);
1340 if (ret) {
1341 ERR("Failed to push context frame during recursive directory removal");
1342 rmdir_frame_fini(&new_frame);
1343 goto end;
1344 }
1345 current_frame_idx++;
1346 /* We break iteration on readdir. */
1347 break;
1348 }
1349 }
1350 if (entry) {
1351 continue;
1352 }
1353
1354 /* Pop rmdir frame. */
1355 if (current_frame->empty) {
1356 ret = lttng_directory_handle_rmdir(
1357 handle, current_path.data);
1358 if (ret) {
1359 if ((flags & LTTNG_DIRECTORY_HANDLE_FAIL_NON_EMPTY_FLAG) ||
1360 errno != ENOENT) {
1361 PERROR("Failed to remove \"%s\" during recursive directory removal",
1362 current_path.data);
1363 goto end;
1364 }
1365 DBG("Non-existing directory stream during recursive directory removal");
1366 }
1367 } else if (current_frame->parent_frame_idx >= 0) {
1368 struct rmdir_frame *parent_frame;
1369
1370 parent_frame = lttng_dynamic_array_get_element(&frames,
1371 current_frame->parent_frame_idx);
1372 assert(parent_frame);
1373 parent_frame->empty = false;
1374 }
1375 ret = lttng_dynamic_array_remove_element(
1376 &frames, current_frame_idx);
1377 if (ret) {
1378 ERR("Failed to pop context frame during recursive directory removal");
1379 goto end;
1380 }
1381 current_frame_idx--;
1382 }
1383 end:
1384 lttng_dynamic_array_reset(&frames);
1385 lttng_dynamic_buffer_reset(&current_path);
1386 return ret;
1387 }
1388
1389 LTTNG_HIDDEN
1390 int lttng_directory_handle_remove_subdirectory_recursive(
1391 const struct lttng_directory_handle *handle,
1392 const char *name,
1393 int flags)
1394 {
1395 return lttng_directory_handle_remove_subdirectory_recursive_as_user(
1396 handle, name, NULL, flags);
1397 }
1398
1399 LTTNG_HIDDEN
1400 int lttng_directory_handle_remove_subdirectory_recursive_as_user(
1401 const struct lttng_directory_handle *handle,
1402 const char *name,
1403 const struct lttng_credentials *creds,
1404 int flags)
1405 {
1406 int ret;
1407
1408 if (!creds) {
1409 /* Run as current user. */
1410 ret = remove_directory_recursive(handle, name, flags);
1411 } else {
1412 ret = _run_as_rmdir_recursive(handle, name, creds->uid,
1413 creds->gid, flags);
1414 }
1415 return ret;
1416 }
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