Port: Replace flock with fnctl
[lttng-tools.git] / src / common / utils.c
1 /*
2 * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
3 * Copyright (C) 2013 - Raphaël Beamonte <raphael.beamonte@gmail.com>
4 * Copyright (C) 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License, version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20 #define _GNU_SOURCE
21 #define _LGPL_SOURCE
22 #include <assert.h>
23 #include <ctype.h>
24 #include <fcntl.h>
25 #include <limits.h>
26 #include <stdlib.h>
27 #include <sys/stat.h>
28 #include <sys/types.h>
29 #include <unistd.h>
30 #include <inttypes.h>
31 #include <grp.h>
32 #include <pwd.h>
33 #include <sys/file.h>
34 #include <dirent.h>
35
36 #include <common/common.h>
37 #include <common/runas.h>
38 #include <common/compat/getenv.h>
39 #include <common/compat/string.h>
40
41 #include "utils.h"
42 #include "defaults.h"
43
44 /*
45 * Return a partial realpath(3) of the path even if the full path does not
46 * exist. For instance, with /tmp/test1/test2/test3, if test2/ does not exist
47 * but the /tmp/test1 does, the real path for /tmp/test1 is concatened with
48 * /test2/test3 then returned. In normal time, realpath(3) fails if the end
49 * point directory does not exist.
50 * In case resolved_path is NULL, the string returned was allocated in the
51 * function and thus need to be freed by the caller. The size argument allows
52 * to specify the size of the resolved_path argument if given, or the size to
53 * allocate.
54 */
55 LTTNG_HIDDEN
56 char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
57 {
58 char *cut_path = NULL, *try_path = NULL, *try_path_prev = NULL;
59 const char *next, *prev, *end;
60
61 /* Safety net */
62 if (path == NULL) {
63 goto error;
64 }
65
66 /*
67 * Identify the end of the path, we don't want to treat the
68 * last char if it is a '/', we will just keep it on the side
69 * to be added at the end, and return a value coherent with
70 * the path given as argument
71 */
72 end = path + strlen(path);
73 if (*(end-1) == '/') {
74 end--;
75 }
76
77 /* Initiate the values of the pointers before looping */
78 next = path;
79 prev = next;
80 /* Only to ensure try_path is not NULL to enter the while */
81 try_path = (char *)next;
82
83 /* Resolve the canonical path of the first part of the path */
84 while (try_path != NULL && next != end) {
85 /*
86 * If there is not any '/' left, we want to try with
87 * the full path
88 */
89 next = strpbrk(next + 1, "/");
90 if (next == NULL) {
91 next = end;
92 }
93
94 /* Cut the part we will be trying to resolve */
95 cut_path = lttng_strndup(path, next - path);
96 if (cut_path == NULL) {
97 PERROR("lttng_strndup");
98 goto error;
99 }
100
101 /* Try to resolve this part */
102 try_path = realpath((char *)cut_path, NULL);
103 if (try_path == NULL) {
104 /*
105 * There was an error, we just want to be assured it
106 * is linked to an unexistent directory, if it's another
107 * reason, we spawn an error
108 */
109 switch (errno) {
110 case ENOENT:
111 /* Ignore the error */
112 break;
113 default:
114 PERROR("realpath (partial_realpath)");
115 goto error;
116 break;
117 }
118 } else {
119 /* Save the place we are before trying the next step */
120 free(try_path_prev);
121 try_path_prev = try_path;
122 prev = next;
123 }
124
125 /* Free the allocated memory */
126 free(cut_path);
127 cut_path = NULL;
128 }
129
130 /* Allocate memory for the resolved path if necessary */
131 if (resolved_path == NULL) {
132 resolved_path = zmalloc(size);
133 if (resolved_path == NULL) {
134 PERROR("zmalloc resolved path");
135 goto error;
136 }
137 }
138
139 /*
140 * If we were able to solve at least partially the path, we can concatenate
141 * what worked and what didn't work
142 */
143 if (try_path_prev != NULL) {
144 /* If we risk to concatenate two '/', we remove one of them */
145 if (try_path_prev[strlen(try_path_prev) - 1] == '/' && prev[0] == '/') {
146 try_path_prev[strlen(try_path_prev) - 1] = '\0';
147 }
148
149 /*
150 * Duplicate the memory used by prev in case resolved_path and
151 * path are pointers for the same memory space
152 */
153 cut_path = strdup(prev);
154 if (cut_path == NULL) {
155 PERROR("strdup");
156 goto error;
157 }
158
159 /* Concatenate the strings */
160 snprintf(resolved_path, size, "%s%s", try_path_prev, cut_path);
161
162 /* Free the allocated memory */
163 free(cut_path);
164 free(try_path_prev);
165 cut_path = NULL;
166 try_path_prev = NULL;
167 /*
168 * Else, we just copy the path in our resolved_path to
169 * return it as is
170 */
171 } else {
172 strncpy(resolved_path, path, size);
173 }
174
175 /* Then we return the 'partially' resolved path */
176 return resolved_path;
177
178 error:
179 free(resolved_path);
180 free(cut_path);
181 return NULL;
182 }
183
184 /*
185 * Make a full resolution of the given path even if it doesn't exist.
186 * This function uses the utils_partial_realpath function to resolve
187 * symlinks and relatives paths at the start of the string, and
188 * implements functionnalities to resolve the './' and '../' strings
189 * in the middle of a path. This function is only necessary because
190 * realpath(3) does not accept to resolve unexistent paths.
191 * The returned string was allocated in the function, it is thus of
192 * the responsibility of the caller to free this memory.
193 */
194 LTTNG_HIDDEN
195 char *utils_expand_path(const char *path)
196 {
197 char *next, *previous, *slash, *start_path, *absolute_path = NULL;
198 char *last_token;
199 int is_dot, is_dotdot;
200
201 /* Safety net */
202 if (path == NULL) {
203 goto error;
204 }
205
206 /* Allocate memory for the absolute_path */
207 absolute_path = zmalloc(PATH_MAX);
208 if (absolute_path == NULL) {
209 PERROR("zmalloc expand path");
210 goto error;
211 }
212
213 /*
214 * If the path is not already absolute nor explicitly relative,
215 * consider we're in the current directory
216 */
217 if (*path != '/' && strncmp(path, "./", 2) != 0 &&
218 strncmp(path, "../", 3) != 0) {
219 snprintf(absolute_path, PATH_MAX, "./%s", path);
220 /* Else, we just copy the path */
221 } else {
222 strncpy(absolute_path, path, PATH_MAX);
223 }
224
225 /* Resolve partially our path */
226 absolute_path = utils_partial_realpath(absolute_path,
227 absolute_path, PATH_MAX);
228
229 /* As long as we find '/./' in the working_path string */
230 while ((next = strstr(absolute_path, "/./"))) {
231
232 /* We prepare the start_path not containing it */
233 start_path = lttng_strndup(absolute_path, next - absolute_path);
234 if (!start_path) {
235 PERROR("lttng_strndup");
236 goto error;
237 }
238 /* And we concatenate it with the part after this string */
239 snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 2);
240
241 free(start_path);
242 }
243
244 /* As long as we find '/../' in the working_path string */
245 while ((next = strstr(absolute_path, "/../"))) {
246 /* We find the last level of directory */
247 previous = absolute_path;
248 while ((slash = strpbrk(previous, "/")) && slash != next) {
249 previous = slash + 1;
250 }
251
252 /* Then we prepare the start_path not containing it */
253 start_path = lttng_strndup(absolute_path, previous - absolute_path);
254 if (!start_path) {
255 PERROR("lttng_strndup");
256 goto error;
257 }
258
259 /* And we concatenate it with the part after the '/../' */
260 snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 4);
261
262 /* We can free the memory used for the start path*/
263 free(start_path);
264
265 /* Then we verify for symlinks using partial_realpath */
266 absolute_path = utils_partial_realpath(absolute_path,
267 absolute_path, PATH_MAX);
268 }
269
270 /* Identify the last token */
271 last_token = strrchr(absolute_path, '/');
272
273 /* Verify that this token is not a relative path */
274 is_dotdot = (strcmp(last_token, "/..") == 0);
275 is_dot = (strcmp(last_token, "/.") == 0);
276
277 /* If it is, take action */
278 if (is_dot || is_dotdot) {
279 /* For both, remove this token */
280 *last_token = '\0';
281
282 /* If it was a reference to parent directory, go back one more time */
283 if (is_dotdot) {
284 last_token = strrchr(absolute_path, '/');
285
286 /* If there was only one level left, we keep the first '/' */
287 if (last_token == absolute_path) {
288 last_token++;
289 }
290
291 *last_token = '\0';
292 }
293 }
294
295 return absolute_path;
296
297 error:
298 free(absolute_path);
299 return NULL;
300 }
301
302 /*
303 * Create a pipe in dst.
304 */
305 LTTNG_HIDDEN
306 int utils_create_pipe(int *dst)
307 {
308 int ret;
309
310 if (dst == NULL) {
311 return -1;
312 }
313
314 ret = pipe(dst);
315 if (ret < 0) {
316 PERROR("create pipe");
317 }
318
319 return ret;
320 }
321
322 /*
323 * Create pipe and set CLOEXEC flag to both fd.
324 *
325 * Make sure the pipe opened by this function are closed at some point. Use
326 * utils_close_pipe().
327 */
328 LTTNG_HIDDEN
329 int utils_create_pipe_cloexec(int *dst)
330 {
331 int ret, i;
332
333 if (dst == NULL) {
334 return -1;
335 }
336
337 ret = utils_create_pipe(dst);
338 if (ret < 0) {
339 goto error;
340 }
341
342 for (i = 0; i < 2; i++) {
343 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
344 if (ret < 0) {
345 PERROR("fcntl pipe cloexec");
346 goto error;
347 }
348 }
349
350 error:
351 return ret;
352 }
353
354 /*
355 * Create pipe and set fd flags to FD_CLOEXEC and O_NONBLOCK.
356 *
357 * Make sure the pipe opened by this function are closed at some point. Use
358 * utils_close_pipe(). Using pipe() and fcntl rather than pipe2() to
359 * support OSes other than Linux 2.6.23+.
360 */
361 LTTNG_HIDDEN
362 int utils_create_pipe_cloexec_nonblock(int *dst)
363 {
364 int ret, i;
365
366 if (dst == NULL) {
367 return -1;
368 }
369
370 ret = utils_create_pipe(dst);
371 if (ret < 0) {
372 goto error;
373 }
374
375 for (i = 0; i < 2; i++) {
376 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
377 if (ret < 0) {
378 PERROR("fcntl pipe cloexec");
379 goto error;
380 }
381 /*
382 * Note: we override any flag that could have been
383 * previously set on the fd.
384 */
385 ret = fcntl(dst[i], F_SETFL, O_NONBLOCK);
386 if (ret < 0) {
387 PERROR("fcntl pipe nonblock");
388 goto error;
389 }
390 }
391
392 error:
393 return ret;
394 }
395
396 /*
397 * Close both read and write side of the pipe.
398 */
399 LTTNG_HIDDEN
400 void utils_close_pipe(int *src)
401 {
402 int i, ret;
403
404 if (src == NULL) {
405 return;
406 }
407
408 for (i = 0; i < 2; i++) {
409 /* Safety check */
410 if (src[i] < 0) {
411 continue;
412 }
413
414 ret = close(src[i]);
415 if (ret) {
416 PERROR("close pipe");
417 }
418 }
419 }
420
421 /*
422 * Create a new string using two strings range.
423 */
424 LTTNG_HIDDEN
425 char *utils_strdupdelim(const char *begin, const char *end)
426 {
427 char *str;
428
429 str = zmalloc(end - begin + 1);
430 if (str == NULL) {
431 PERROR("zmalloc strdupdelim");
432 goto error;
433 }
434
435 memcpy(str, begin, end - begin);
436 str[end - begin] = '\0';
437
438 error:
439 return str;
440 }
441
442 /*
443 * Set CLOEXEC flag to the give file descriptor.
444 */
445 LTTNG_HIDDEN
446 int utils_set_fd_cloexec(int fd)
447 {
448 int ret;
449
450 if (fd < 0) {
451 ret = -EINVAL;
452 goto end;
453 }
454
455 ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
456 if (ret < 0) {
457 PERROR("fcntl cloexec");
458 ret = -errno;
459 }
460
461 end:
462 return ret;
463 }
464
465 /*
466 * Create pid file to the given path and filename.
467 */
468 LTTNG_HIDDEN
469 int utils_create_pid_file(pid_t pid, const char *filepath)
470 {
471 int ret;
472 FILE *fp;
473
474 assert(filepath);
475
476 fp = fopen(filepath, "w");
477 if (fp == NULL) {
478 PERROR("open pid file %s", filepath);
479 ret = -1;
480 goto error;
481 }
482
483 ret = fprintf(fp, "%d\n", pid);
484 if (ret < 0) {
485 PERROR("fprintf pid file");
486 goto error;
487 }
488
489 if (fclose(fp)) {
490 PERROR("fclose");
491 }
492 DBG("Pid %d written in file %s", pid, filepath);
493 ret = 0;
494 error:
495 return ret;
496 }
497
498 /*
499 * Create lock file to the given path and filename.
500 * Returns the associated file descriptor, -1 on error.
501 */
502 LTTNG_HIDDEN
503 int utils_create_lock_file(const char *filepath)
504 {
505 int ret;
506 int fd;
507 struct flock lock;
508
509 assert(filepath);
510
511 memset(&lock, 0, sizeof(lock));
512 fd = open(filepath, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR |
513 S_IRGRP | S_IWGRP);
514 if (fd < 0) {
515 PERROR("open lock file %s", filepath);
516 ret = -1;
517 goto error;
518 }
519
520 /*
521 * Attempt to lock the file. If this fails, there is
522 * already a process using the same lock file running
523 * and we should exit.
524 */
525 lock.l_whence = SEEK_SET;
526 lock.l_type = F_WRLCK;
527
528 ret = fcntl(fd, F_SETLK, &lock);
529 if (ret == -1) {
530 PERROR("fcntl lock file");
531 ERR("Could not get lock file %s, another instance is running.",
532 filepath);
533 if (close(fd)) {
534 PERROR("close lock file");
535 }
536 fd = ret;
537 goto error;
538 }
539
540 error:
541 return fd;
542 }
543
544 /*
545 * Create directory using the given path and mode.
546 *
547 * On success, return 0 else a negative error code.
548 */
549 LTTNG_HIDDEN
550 int utils_mkdir(const char *path, mode_t mode, int uid, int gid)
551 {
552 int ret;
553
554 if (uid < 0 || gid < 0) {
555 ret = mkdir(path, mode);
556 } else {
557 ret = run_as_mkdir(path, mode, uid, gid);
558 }
559 if (ret < 0) {
560 if (errno != EEXIST) {
561 PERROR("mkdir %s, uid %d, gid %d", path ? path : "NULL",
562 uid, gid);
563 } else {
564 ret = 0;
565 }
566 }
567
568 return ret;
569 }
570
571 /*
572 * Internal version of mkdir_recursive. Runs as the current user.
573 * Don't call directly; use utils_mkdir_recursive().
574 *
575 * This function is ominously marked as "unsafe" since it should only
576 * be called by a caller that has transitioned to the uid and gid under which
577 * the directory creation should occur.
578 */
579 LTTNG_HIDDEN
580 int _utils_mkdir_recursive_unsafe(const char *path, mode_t mode)
581 {
582 char *p, tmp[PATH_MAX];
583 size_t len;
584 int ret;
585
586 assert(path);
587
588 ret = snprintf(tmp, sizeof(tmp), "%s", path);
589 if (ret < 0) {
590 PERROR("snprintf mkdir");
591 goto error;
592 }
593
594 len = ret;
595 if (tmp[len - 1] == '/') {
596 tmp[len - 1] = 0;
597 }
598
599 for (p = tmp + 1; *p; p++) {
600 if (*p == '/') {
601 *p = 0;
602 if (tmp[strlen(tmp) - 1] == '.' &&
603 tmp[strlen(tmp) - 2] == '.' &&
604 tmp[strlen(tmp) - 3] == '/') {
605 ERR("Using '/../' is not permitted in the trace path (%s)",
606 tmp);
607 ret = -1;
608 goto error;
609 }
610 ret = mkdir(tmp, mode);
611 if (ret < 0) {
612 if (errno != EEXIST) {
613 PERROR("mkdir recursive");
614 ret = -errno;
615 goto error;
616 }
617 }
618 *p = '/';
619 }
620 }
621
622 ret = mkdir(tmp, mode);
623 if (ret < 0) {
624 if (errno != EEXIST) {
625 PERROR("mkdir recursive last element");
626 ret = -errno;
627 } else {
628 ret = 0;
629 }
630 }
631
632 error:
633 return ret;
634 }
635
636 /*
637 * Recursively create directory using the given path and mode, under the
638 * provided uid and gid.
639 *
640 * On success, return 0 else a negative error code.
641 */
642 LTTNG_HIDDEN
643 int utils_mkdir_recursive(const char *path, mode_t mode, int uid, int gid)
644 {
645 int ret;
646
647 if (uid < 0 || gid < 0) {
648 /* Run as current user. */
649 ret = _utils_mkdir_recursive_unsafe(path, mode);
650 } else {
651 ret = run_as_mkdir_recursive(path, mode, uid, gid);
652 }
653 if (ret < 0) {
654 PERROR("mkdir %s, uid %d, gid %d", path ? path : "NULL",
655 uid, gid);
656 }
657
658 return ret;
659 }
660
661 /*
662 * path is the output parameter. It needs to be PATH_MAX len.
663 *
664 * Return 0 on success or else a negative value.
665 */
666 static int utils_stream_file_name(char *path,
667 const char *path_name, const char *file_name,
668 uint64_t size, uint64_t count,
669 const char *suffix)
670 {
671 int ret;
672 char full_path[PATH_MAX];
673 char *path_name_suffix = NULL;
674 char *extra = NULL;
675
676 ret = snprintf(full_path, sizeof(full_path), "%s/%s",
677 path_name, file_name);
678 if (ret < 0) {
679 PERROR("snprintf create output file");
680 goto error;
681 }
682
683 /* Setup extra string if suffix or/and a count is needed. */
684 if (size > 0 && suffix) {
685 ret = asprintf(&extra, "_%" PRIu64 "%s", count, suffix);
686 } else if (size > 0) {
687 ret = asprintf(&extra, "_%" PRIu64, count);
688 } else if (suffix) {
689 ret = asprintf(&extra, "%s", suffix);
690 }
691 if (ret < 0) {
692 PERROR("Allocating extra string to name");
693 goto error;
694 }
695
696 /*
697 * If we split the trace in multiple files, we have to add the count at
698 * the end of the tracefile name.
699 */
700 if (extra) {
701 ret = asprintf(&path_name_suffix, "%s%s", full_path, extra);
702 if (ret < 0) {
703 PERROR("Allocating path name with extra string");
704 goto error_free_suffix;
705 }
706 strncpy(path, path_name_suffix, PATH_MAX - 1);
707 path[PATH_MAX - 1] = '\0';
708 } else {
709 strncpy(path, full_path, PATH_MAX - 1);
710 }
711 path[PATH_MAX - 1] = '\0';
712 ret = 0;
713
714 free(path_name_suffix);
715 error_free_suffix:
716 free(extra);
717 error:
718 return ret;
719 }
720
721 /*
722 * Create the stream file on disk.
723 *
724 * Return 0 on success or else a negative value.
725 */
726 LTTNG_HIDDEN
727 int utils_create_stream_file(const char *path_name, char *file_name, uint64_t size,
728 uint64_t count, int uid, int gid, char *suffix)
729 {
730 int ret, flags, mode;
731 char path[PATH_MAX];
732
733 ret = utils_stream_file_name(path, path_name, file_name,
734 size, count, suffix);
735 if (ret < 0) {
736 goto error;
737 }
738
739 flags = O_WRONLY | O_CREAT | O_TRUNC;
740 /* Open with 660 mode */
741 mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
742
743 if (uid < 0 || gid < 0) {
744 ret = open(path, flags, mode);
745 } else {
746 ret = run_as_open(path, flags, mode, uid, gid);
747 }
748 if (ret < 0) {
749 PERROR("open stream path %s", path);
750 }
751 error:
752 return ret;
753 }
754
755 /*
756 * Unlink the stream tracefile from disk.
757 *
758 * Return 0 on success or else a negative value.
759 */
760 LTTNG_HIDDEN
761 int utils_unlink_stream_file(const char *path_name, char *file_name, uint64_t size,
762 uint64_t count, int uid, int gid, char *suffix)
763 {
764 int ret;
765 char path[PATH_MAX];
766
767 ret = utils_stream_file_name(path, path_name, file_name,
768 size, count, suffix);
769 if (ret < 0) {
770 goto error;
771 }
772 if (uid < 0 || gid < 0) {
773 ret = unlink(path);
774 } else {
775 ret = run_as_unlink(path, uid, gid);
776 }
777 if (ret < 0) {
778 goto error;
779 }
780 error:
781 DBG("utils_unlink_stream_file %s returns %d", path, ret);
782 return ret;
783 }
784
785 /*
786 * Change the output tracefile according to the given size and count The
787 * new_count pointer is set during this operation.
788 *
789 * From the consumer, the stream lock MUST be held before calling this function
790 * because we are modifying the stream status.
791 *
792 * Return 0 on success or else a negative value.
793 */
794 LTTNG_HIDDEN
795 int utils_rotate_stream_file(char *path_name, char *file_name, uint64_t size,
796 uint64_t count, int uid, int gid, int out_fd, uint64_t *new_count,
797 int *stream_fd)
798 {
799 int ret;
800
801 assert(new_count);
802 assert(stream_fd);
803
804 ret = close(out_fd);
805 if (ret < 0) {
806 PERROR("Closing tracefile");
807 goto error;
808 }
809
810 if (count > 0) {
811 /*
812 * In tracefile rotation, for the relay daemon we need
813 * to unlink the old file if present, because it may
814 * still be open in reading by the live thread, and we
815 * need to ensure that we do not overwrite the content
816 * between get_index and get_packet. Since we have no
817 * way to verify integrity of the data content compared
818 * to the associated index, we need to ensure the reader
819 * has exclusive access to the file content, and that
820 * the open of the data file is performed in get_index.
821 * Unlinking the old file rather than overwriting it
822 * achieves this.
823 */
824 *new_count = (*new_count + 1) % count;
825 ret = utils_unlink_stream_file(path_name, file_name,
826 size, *new_count, uid, gid, 0);
827 if (ret < 0 && errno != ENOENT) {
828 goto error;
829 }
830 } else {
831 (*new_count)++;
832 }
833
834 ret = utils_create_stream_file(path_name, file_name, size, *new_count,
835 uid, gid, 0);
836 if (ret < 0) {
837 goto error;
838 }
839 *stream_fd = ret;
840
841 /* Success. */
842 ret = 0;
843
844 error:
845 return ret;
846 }
847
848
849 /**
850 * Parse a string that represents a size in human readable format. It
851 * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
852 *
853 * The suffix multiply the integer by:
854 * 'k': 1024
855 * 'M': 1024^2
856 * 'G': 1024^3
857 *
858 * @param str The string to parse.
859 * @param size Pointer to a uint64_t that will be filled with the
860 * resulting size.
861 *
862 * @return 0 on success, -1 on failure.
863 */
864 LTTNG_HIDDEN
865 int utils_parse_size_suffix(const char * const str, uint64_t * const size)
866 {
867 int ret;
868 uint64_t base_size;
869 long shift = 0;
870 const char *str_end;
871 char *num_end;
872
873 if (!str) {
874 DBG("utils_parse_size_suffix: received a NULL string.");
875 ret = -1;
876 goto end;
877 }
878
879 /* strtoull will accept a negative number, but we don't want to. */
880 if (strchr(str, '-') != NULL) {
881 DBG("utils_parse_size_suffix: invalid size string, should not contain '-'.");
882 ret = -1;
883 goto end;
884 }
885
886 /* str_end will point to the \0 */
887 str_end = str + strlen(str);
888 errno = 0;
889 base_size = strtoull(str, &num_end, 0);
890 if (errno != 0) {
891 PERROR("utils_parse_size_suffix strtoull");
892 ret = -1;
893 goto end;
894 }
895
896 if (num_end == str) {
897 /* strtoull parsed nothing, not good. */
898 DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
899 ret = -1;
900 goto end;
901 }
902
903 /* Check if a prefix is present. */
904 switch (*num_end) {
905 case 'G':
906 shift = GIBI_LOG2;
907 num_end++;
908 break;
909 case 'M': /* */
910 shift = MEBI_LOG2;
911 num_end++;
912 break;
913 case 'K':
914 case 'k':
915 shift = KIBI_LOG2;
916 num_end++;
917 break;
918 case '\0':
919 break;
920 default:
921 DBG("utils_parse_size_suffix: invalid suffix.");
922 ret = -1;
923 goto end;
924 }
925
926 /* Check for garbage after the valid input. */
927 if (num_end != str_end) {
928 DBG("utils_parse_size_suffix: Garbage after size string.");
929 ret = -1;
930 goto end;
931 }
932
933 *size = base_size << shift;
934
935 /* Check for overflow */
936 if ((*size >> shift) != base_size) {
937 DBG("utils_parse_size_suffix: oops, overflow detected.");
938 ret = -1;
939 goto end;
940 }
941
942 ret = 0;
943 end:
944 return ret;
945 }
946
947 /*
948 * fls: returns the position of the most significant bit.
949 * Returns 0 if no bit is set, else returns the position of the most
950 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
951 */
952 #if defined(__i386) || defined(__x86_64)
953 static inline unsigned int fls_u32(uint32_t x)
954 {
955 int r;
956
957 asm("bsrl %1,%0\n\t"
958 "jnz 1f\n\t"
959 "movl $-1,%0\n\t"
960 "1:\n\t"
961 : "=r" (r) : "rm" (x));
962 return r + 1;
963 }
964 #define HAS_FLS_U32
965 #endif
966
967 #ifndef HAS_FLS_U32
968 static __attribute__((unused)) unsigned int fls_u32(uint32_t x)
969 {
970 unsigned int r = 32;
971
972 if (!x) {
973 return 0;
974 }
975 if (!(x & 0xFFFF0000U)) {
976 x <<= 16;
977 r -= 16;
978 }
979 if (!(x & 0xFF000000U)) {
980 x <<= 8;
981 r -= 8;
982 }
983 if (!(x & 0xF0000000U)) {
984 x <<= 4;
985 r -= 4;
986 }
987 if (!(x & 0xC0000000U)) {
988 x <<= 2;
989 r -= 2;
990 }
991 if (!(x & 0x80000000U)) {
992 x <<= 1;
993 r -= 1;
994 }
995 return r;
996 }
997 #endif
998
999 /*
1000 * Return the minimum order for which x <= (1UL << order).
1001 * Return -1 if x is 0.
1002 */
1003 LTTNG_HIDDEN
1004 int utils_get_count_order_u32(uint32_t x)
1005 {
1006 if (!x) {
1007 return -1;
1008 }
1009
1010 return fls_u32(x - 1);
1011 }
1012
1013 /**
1014 * Obtain the value of LTTNG_HOME environment variable, if exists.
1015 * Otherwise returns the value of HOME.
1016 */
1017 LTTNG_HIDDEN
1018 char *utils_get_home_dir(void)
1019 {
1020 char *val = NULL;
1021 struct passwd *pwd;
1022
1023 val = lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
1024 if (val != NULL) {
1025 goto end;
1026 }
1027 val = lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
1028 if (val != NULL) {
1029 goto end;
1030 }
1031
1032 /* Fallback on the password file entry. */
1033 pwd = getpwuid(getuid());
1034 if (!pwd) {
1035 goto end;
1036 }
1037 val = pwd->pw_dir;
1038
1039 DBG3("Home directory is '%s'", val);
1040
1041 end:
1042 return val;
1043 }
1044
1045 /**
1046 * Get user's home directory. Dynamically allocated, must be freed
1047 * by the caller.
1048 */
1049 LTTNG_HIDDEN
1050 char *utils_get_user_home_dir(uid_t uid)
1051 {
1052 struct passwd pwd;
1053 struct passwd *result;
1054 char *home_dir = NULL;
1055 char *buf = NULL;
1056 long buflen;
1057 int ret;
1058
1059 buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
1060 if (buflen == -1) {
1061 goto end;
1062 }
1063 retry:
1064 buf = zmalloc(buflen);
1065 if (!buf) {
1066 goto end;
1067 }
1068
1069 ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
1070 if (ret || !result) {
1071 if (ret == ERANGE) {
1072 free(buf);
1073 buflen *= 2;
1074 goto retry;
1075 }
1076 goto end;
1077 }
1078
1079 home_dir = strdup(pwd.pw_dir);
1080 end:
1081 free(buf);
1082 return home_dir;
1083 }
1084
1085 /*
1086 * Obtain the value of LTTNG_KMOD_PROBES environment variable, if exists.
1087 * Otherwise returns NULL.
1088 */
1089 LTTNG_HIDDEN
1090 char *utils_get_kmod_probes_list(void)
1091 {
1092 return lttng_secure_getenv(DEFAULT_LTTNG_KMOD_PROBES);
1093 }
1094
1095 /*
1096 * Obtain the value of LTTNG_EXTRA_KMOD_PROBES environment variable, if
1097 * exists. Otherwise returns NULL.
1098 */
1099 LTTNG_HIDDEN
1100 char *utils_get_extra_kmod_probes_list(void)
1101 {
1102 return lttng_secure_getenv(DEFAULT_LTTNG_EXTRA_KMOD_PROBES);
1103 }
1104
1105 /*
1106 * With the given format, fill dst with the time of len maximum siz.
1107 *
1108 * Return amount of bytes set in the buffer or else 0 on error.
1109 */
1110 LTTNG_HIDDEN
1111 size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
1112 {
1113 size_t ret;
1114 time_t rawtime;
1115 struct tm *timeinfo;
1116
1117 assert(format);
1118 assert(dst);
1119
1120 /* Get date and time for session path */
1121 time(&rawtime);
1122 timeinfo = localtime(&rawtime);
1123 ret = strftime(dst, len, format, timeinfo);
1124 if (ret == 0) {
1125 ERR("Unable to strftime with format %s at dst %p of len %zu", format,
1126 dst, len);
1127 }
1128
1129 return ret;
1130 }
1131
1132 /*
1133 * Return the group ID matching name, else 0 if it cannot be found.
1134 */
1135 LTTNG_HIDDEN
1136 gid_t utils_get_group_id(const char *name)
1137 {
1138 struct group *grp;
1139
1140 grp = getgrnam(name);
1141 if (!grp) {
1142 static volatile int warn_once;
1143
1144 if (!warn_once) {
1145 WARN("No tracing group detected");
1146 warn_once = 1;
1147 }
1148 return 0;
1149 }
1150 return grp->gr_gid;
1151 }
1152
1153 /*
1154 * Return a newly allocated option string. This string is to be used as the
1155 * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
1156 * of elements in the long_options array. Returns NULL if the string's
1157 * allocation fails.
1158 */
1159 LTTNG_HIDDEN
1160 char *utils_generate_optstring(const struct option *long_options,
1161 size_t opt_count)
1162 {
1163 int i;
1164 size_t string_len = opt_count, str_pos = 0;
1165 char *optstring;
1166
1167 /*
1168 * Compute the necessary string length. One letter per option, two when an
1169 * argument is necessary, and a trailing NULL.
1170 */
1171 for (i = 0; i < opt_count; i++) {
1172 string_len += long_options[i].has_arg ? 1 : 0;
1173 }
1174
1175 optstring = zmalloc(string_len);
1176 if (!optstring) {
1177 goto end;
1178 }
1179
1180 for (i = 0; i < opt_count; i++) {
1181 if (!long_options[i].name) {
1182 /* Got to the trailing NULL element */
1183 break;
1184 }
1185
1186 if (long_options[i].val != '\0') {
1187 optstring[str_pos++] = (char) long_options[i].val;
1188 if (long_options[i].has_arg) {
1189 optstring[str_pos++] = ':';
1190 }
1191 }
1192 }
1193
1194 end:
1195 return optstring;
1196 }
1197
1198 /*
1199 * Try to remove a hierarchy of empty directories, recursively. Don't unlink
1200 * any file. Try to rmdir any empty directory within the hierarchy.
1201 */
1202 LTTNG_HIDDEN
1203 int utils_recursive_rmdir(const char *path)
1204 {
1205 DIR *dir;
1206 size_t path_len;
1207 int dir_fd, ret = 0, closeret, is_empty = 1;
1208 struct dirent *entry;
1209
1210 /* Open directory */
1211 dir = opendir(path);
1212 if (!dir) {
1213 PERROR("Cannot open '%s' path", path);
1214 return -1;
1215 }
1216 dir_fd = dirfd(dir);
1217 if (dir_fd < 0) {
1218 PERROR("dirfd");
1219 return -1;
1220 }
1221
1222 path_len = strlen(path);
1223 while ((entry = readdir(dir))) {
1224 if (!strcmp(entry->d_name, ".")
1225 || !strcmp(entry->d_name, ".."))
1226 continue;
1227
1228 struct stat st;
1229 size_t name_len;
1230 char filename[PATH_MAX];
1231
1232 name_len = strlen(entry->d_name);
1233 if (path_len + name_len + 2 > sizeof(filename)) {
1234 ERR("Failed to remove file: path name too long (%s/%s)",
1235 path, entry->d_name);
1236 continue;
1237 }
1238 if (snprintf(filename, sizeof(filename), "%s/%s",
1239 path, entry->d_name) < 0) {
1240 ERR("Failed to format path.");
1241 continue;
1242 }
1243
1244 if (stat(filename, &st)) {
1245 PERROR("stat");
1246 continue;
1247 }
1248
1249 if (S_ISDIR(st.st_mode)) {
1250 char subpath[PATH_MAX];
1251
1252 strncpy(subpath, path, PATH_MAX);
1253 subpath[PATH_MAX - 1] = '\0';
1254 strncat(subpath, "/",
1255 PATH_MAX - strlen(subpath) - 1);
1256 strncat(subpath, entry->d_name,
1257 PATH_MAX - strlen(subpath) - 1);
1258 if (utils_recursive_rmdir(subpath)) {
1259 is_empty = 0;
1260 }
1261 } else if (S_ISREG(st.st_mode)) {
1262 is_empty = 0;
1263 } else {
1264 ret = -EINVAL;
1265 goto end;
1266 }
1267 }
1268 end:
1269 closeret = closedir(dir);
1270 if (closeret) {
1271 PERROR("closedir");
1272 }
1273 if (is_empty) {
1274 DBG3("Attempting rmdir %s", path);
1275 ret = rmdir(path);
1276 }
1277 return ret;
1278 }
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