Introduce utils_parse_time_suffix
[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 _LGPL_SOURCE
21 #include <assert.h>
22 #include <ctype.h>
23 #include <fcntl.h>
24 #include <limits.h>
25 #include <stdlib.h>
26 #include <sys/stat.h>
27 #include <sys/types.h>
28 #include <unistd.h>
29 #include <inttypes.h>
30 #include <grp.h>
31 #include <pwd.h>
32 #include <sys/file.h>
33 #include <unistd.h>
34
35 #include <common/common.h>
36 #include <common/runas.h>
37 #include <common/compat/getenv.h>
38 #include <common/compat/string.h>
39 #include <common/compat/dirent.h>
40 #include <lttng/constant.h>
41
42 #include "utils.h"
43 #include "defaults.h"
44
45 /*
46 * Return a partial realpath(3) of the path even if the full path does not
47 * exist. For instance, with /tmp/test1/test2/test3, if test2/ does not exist
48 * but the /tmp/test1 does, the real path for /tmp/test1 is concatened with
49 * /test2/test3 then returned. In normal time, realpath(3) fails if the end
50 * point directory does not exist.
51 * In case resolved_path is NULL, the string returned was allocated in the
52 * function and thus need to be freed by the caller. The size argument allows
53 * to specify the size of the resolved_path argument if given, or the size to
54 * allocate.
55 */
56 LTTNG_HIDDEN
57 char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
58 {
59 char *cut_path = NULL, *try_path = NULL, *try_path_prev = NULL;
60 const char *next, *prev, *end;
61
62 /* Safety net */
63 if (path == NULL) {
64 goto error;
65 }
66
67 /*
68 * Identify the end of the path, we don't want to treat the
69 * last char if it is a '/', we will just keep it on the side
70 * to be added at the end, and return a value coherent with
71 * the path given as argument
72 */
73 end = path + strlen(path);
74 if (*(end-1) == '/') {
75 end--;
76 }
77
78 /* Initiate the values of the pointers before looping */
79 next = path;
80 prev = next;
81 /* Only to ensure try_path is not NULL to enter the while */
82 try_path = (char *)next;
83
84 /* Resolve the canonical path of the first part of the path */
85 while (try_path != NULL && next != end) {
86 char *try_path_buf = NULL;
87
88 /*
89 * If there is not any '/' left, we want to try with
90 * the full path
91 */
92 next = strpbrk(next + 1, "/");
93 if (next == NULL) {
94 next = end;
95 }
96
97 /* Cut the part we will be trying to resolve */
98 cut_path = lttng_strndup(path, next - path);
99 if (cut_path == NULL) {
100 PERROR("lttng_strndup");
101 goto error;
102 }
103
104 try_path_buf = zmalloc(LTTNG_PATH_MAX);
105 if (!try_path_buf) {
106 PERROR("zmalloc");
107 goto error;
108 }
109
110 /* Try to resolve this part */
111 try_path = realpath((char *) cut_path, try_path_buf);
112 if (try_path == NULL) {
113 free(try_path_buf);
114 /*
115 * There was an error, we just want to be assured it
116 * is linked to an unexistent directory, if it's another
117 * reason, we spawn an error
118 */
119 switch (errno) {
120 case ENOENT:
121 /* Ignore the error */
122 break;
123 default:
124 PERROR("realpath (partial_realpath)");
125 goto error;
126 break;
127 }
128 } else {
129 /* Save the place we are before trying the next step */
130 try_path_buf = NULL;
131 free(try_path_prev);
132 try_path_prev = try_path;
133 prev = next;
134 }
135
136 /* Free the allocated memory */
137 free(cut_path);
138 cut_path = NULL;
139 }
140
141 /* Allocate memory for the resolved path if necessary */
142 if (resolved_path == NULL) {
143 resolved_path = zmalloc(size);
144 if (resolved_path == NULL) {
145 PERROR("zmalloc resolved path");
146 goto error;
147 }
148 }
149
150 /*
151 * If we were able to solve at least partially the path, we can concatenate
152 * what worked and what didn't work
153 */
154 if (try_path_prev != NULL) {
155 /* If we risk to concatenate two '/', we remove one of them */
156 if (try_path_prev[strlen(try_path_prev) - 1] == '/' && prev[0] == '/') {
157 try_path_prev[strlen(try_path_prev) - 1] = '\0';
158 }
159
160 /*
161 * Duplicate the memory used by prev in case resolved_path and
162 * path are pointers for the same memory space
163 */
164 cut_path = strdup(prev);
165 if (cut_path == NULL) {
166 PERROR("strdup");
167 goto error;
168 }
169
170 /* Concatenate the strings */
171 snprintf(resolved_path, size, "%s%s", try_path_prev, cut_path);
172
173 /* Free the allocated memory */
174 free(cut_path);
175 free(try_path_prev);
176 cut_path = NULL;
177 try_path_prev = NULL;
178 /*
179 * Else, we just copy the path in our resolved_path to
180 * return it as is
181 */
182 } else {
183 strncpy(resolved_path, path, size);
184 }
185
186 /* Then we return the 'partially' resolved path */
187 return resolved_path;
188
189 error:
190 free(resolved_path);
191 free(cut_path);
192 free(try_path);
193 if (try_path_prev != try_path) {
194 free(try_path_prev);
195 }
196 return NULL;
197 }
198
199 /*
200 * Make a full resolution of the given path even if it doesn't exist.
201 * This function uses the utils_partial_realpath function to resolve
202 * symlinks and relatives paths at the start of the string, and
203 * implements functionnalities to resolve the './' and '../' strings
204 * in the middle of a path. This function is only necessary because
205 * realpath(3) does not accept to resolve unexistent paths.
206 * The returned string was allocated in the function, it is thus of
207 * the responsibility of the caller to free this memory.
208 */
209 LTTNG_HIDDEN
210 char *utils_expand_path(const char *path)
211 {
212 char *next, *previous, *slash, *start_path, *absolute_path = NULL;
213 char *last_token;
214 int is_dot, is_dotdot;
215
216 /* Safety net */
217 if (path == NULL) {
218 goto error;
219 }
220
221 /* Allocate memory for the absolute_path */
222 absolute_path = zmalloc(PATH_MAX);
223 if (absolute_path == NULL) {
224 PERROR("zmalloc expand path");
225 goto error;
226 }
227
228 /*
229 * If the path is not already absolute nor explicitly relative,
230 * consider we're in the current directory
231 */
232 if (*path != '/' && strncmp(path, "./", 2) != 0 &&
233 strncmp(path, "../", 3) != 0) {
234 snprintf(absolute_path, PATH_MAX, "./%s", path);
235 /* Else, we just copy the path */
236 } else {
237 strncpy(absolute_path, path, PATH_MAX);
238 }
239
240 /* Resolve partially our path */
241 absolute_path = utils_partial_realpath(absolute_path,
242 absolute_path, PATH_MAX);
243
244 /* As long as we find '/./' in the working_path string */
245 while ((next = strstr(absolute_path, "/./"))) {
246
247 /* We prepare the start_path not containing it */
248 start_path = lttng_strndup(absolute_path, next - absolute_path);
249 if (!start_path) {
250 PERROR("lttng_strndup");
251 goto error;
252 }
253 /* And we concatenate it with the part after this string */
254 snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 2);
255
256 free(start_path);
257 }
258
259 /* As long as we find '/../' in the working_path string */
260 while ((next = strstr(absolute_path, "/../"))) {
261 /* We find the last level of directory */
262 previous = absolute_path;
263 while ((slash = strpbrk(previous, "/")) && slash != next) {
264 previous = slash + 1;
265 }
266
267 /* Then we prepare the start_path not containing it */
268 start_path = lttng_strndup(absolute_path, previous - absolute_path);
269 if (!start_path) {
270 PERROR("lttng_strndup");
271 goto error;
272 }
273
274 /* And we concatenate it with the part after the '/../' */
275 snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 4);
276
277 /* We can free the memory used for the start path*/
278 free(start_path);
279
280 /* Then we verify for symlinks using partial_realpath */
281 absolute_path = utils_partial_realpath(absolute_path,
282 absolute_path, PATH_MAX);
283 }
284
285 /* Identify the last token */
286 last_token = strrchr(absolute_path, '/');
287
288 /* Verify that this token is not a relative path */
289 is_dotdot = (strcmp(last_token, "/..") == 0);
290 is_dot = (strcmp(last_token, "/.") == 0);
291
292 /* If it is, take action */
293 if (is_dot || is_dotdot) {
294 /* For both, remove this token */
295 *last_token = '\0';
296
297 /* If it was a reference to parent directory, go back one more time */
298 if (is_dotdot) {
299 last_token = strrchr(absolute_path, '/');
300
301 /* If there was only one level left, we keep the first '/' */
302 if (last_token == absolute_path) {
303 last_token++;
304 }
305
306 *last_token = '\0';
307 }
308 }
309
310 return absolute_path;
311
312 error:
313 free(absolute_path);
314 return NULL;
315 }
316
317 /*
318 * Create a pipe in dst.
319 */
320 LTTNG_HIDDEN
321 int utils_create_pipe(int *dst)
322 {
323 int ret;
324
325 if (dst == NULL) {
326 return -1;
327 }
328
329 ret = pipe(dst);
330 if (ret < 0) {
331 PERROR("create pipe");
332 }
333
334 return ret;
335 }
336
337 /*
338 * Create pipe and set CLOEXEC flag to both fd.
339 *
340 * Make sure the pipe opened by this function are closed at some point. Use
341 * utils_close_pipe().
342 */
343 LTTNG_HIDDEN
344 int utils_create_pipe_cloexec(int *dst)
345 {
346 int ret, i;
347
348 if (dst == NULL) {
349 return -1;
350 }
351
352 ret = utils_create_pipe(dst);
353 if (ret < 0) {
354 goto error;
355 }
356
357 for (i = 0; i < 2; i++) {
358 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
359 if (ret < 0) {
360 PERROR("fcntl pipe cloexec");
361 goto error;
362 }
363 }
364
365 error:
366 return ret;
367 }
368
369 /*
370 * Create pipe and set fd flags to FD_CLOEXEC and O_NONBLOCK.
371 *
372 * Make sure the pipe opened by this function are closed at some point. Use
373 * utils_close_pipe(). Using pipe() and fcntl rather than pipe2() to
374 * support OSes other than Linux 2.6.23+.
375 */
376 LTTNG_HIDDEN
377 int utils_create_pipe_cloexec_nonblock(int *dst)
378 {
379 int ret, i;
380
381 if (dst == NULL) {
382 return -1;
383 }
384
385 ret = utils_create_pipe(dst);
386 if (ret < 0) {
387 goto error;
388 }
389
390 for (i = 0; i < 2; i++) {
391 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
392 if (ret < 0) {
393 PERROR("fcntl pipe cloexec");
394 goto error;
395 }
396 /*
397 * Note: we override any flag that could have been
398 * previously set on the fd.
399 */
400 ret = fcntl(dst[i], F_SETFL, O_NONBLOCK);
401 if (ret < 0) {
402 PERROR("fcntl pipe nonblock");
403 goto error;
404 }
405 }
406
407 error:
408 return ret;
409 }
410
411 /*
412 * Close both read and write side of the pipe.
413 */
414 LTTNG_HIDDEN
415 void utils_close_pipe(int *src)
416 {
417 int i, ret;
418
419 if (src == NULL) {
420 return;
421 }
422
423 for (i = 0; i < 2; i++) {
424 /* Safety check */
425 if (src[i] < 0) {
426 continue;
427 }
428
429 ret = close(src[i]);
430 if (ret) {
431 PERROR("close pipe");
432 }
433 }
434 }
435
436 /*
437 * Create a new string using two strings range.
438 */
439 LTTNG_HIDDEN
440 char *utils_strdupdelim(const char *begin, const char *end)
441 {
442 char *str;
443
444 str = zmalloc(end - begin + 1);
445 if (str == NULL) {
446 PERROR("zmalloc strdupdelim");
447 goto error;
448 }
449
450 memcpy(str, begin, end - begin);
451 str[end - begin] = '\0';
452
453 error:
454 return str;
455 }
456
457 /*
458 * Set CLOEXEC flag to the give file descriptor.
459 */
460 LTTNG_HIDDEN
461 int utils_set_fd_cloexec(int fd)
462 {
463 int ret;
464
465 if (fd < 0) {
466 ret = -EINVAL;
467 goto end;
468 }
469
470 ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
471 if (ret < 0) {
472 PERROR("fcntl cloexec");
473 ret = -errno;
474 }
475
476 end:
477 return ret;
478 }
479
480 /*
481 * Create pid file to the given path and filename.
482 */
483 LTTNG_HIDDEN
484 int utils_create_pid_file(pid_t pid, const char *filepath)
485 {
486 int ret;
487 FILE *fp;
488
489 assert(filepath);
490
491 fp = fopen(filepath, "w");
492 if (fp == NULL) {
493 PERROR("open pid file %s", filepath);
494 ret = -1;
495 goto error;
496 }
497
498 ret = fprintf(fp, "%d\n", (int) pid);
499 if (ret < 0) {
500 PERROR("fprintf pid file");
501 goto error;
502 }
503
504 if (fclose(fp)) {
505 PERROR("fclose");
506 }
507 DBG("Pid %d written in file %s", (int) pid, filepath);
508 ret = 0;
509 error:
510 return ret;
511 }
512
513 /*
514 * Create lock file to the given path and filename.
515 * Returns the associated file descriptor, -1 on error.
516 */
517 LTTNG_HIDDEN
518 int utils_create_lock_file(const char *filepath)
519 {
520 int ret;
521 int fd;
522 struct flock lock;
523
524 assert(filepath);
525
526 memset(&lock, 0, sizeof(lock));
527 fd = open(filepath, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR |
528 S_IRGRP | S_IWGRP);
529 if (fd < 0) {
530 PERROR("open lock file %s", filepath);
531 fd = -1;
532 goto error;
533 }
534
535 /*
536 * Attempt to lock the file. If this fails, there is
537 * already a process using the same lock file running
538 * and we should exit.
539 */
540 lock.l_whence = SEEK_SET;
541 lock.l_type = F_WRLCK;
542
543 ret = fcntl(fd, F_SETLK, &lock);
544 if (ret == -1) {
545 PERROR("fcntl lock file");
546 ERR("Could not get lock file %s, another instance is running.",
547 filepath);
548 if (close(fd)) {
549 PERROR("close lock file");
550 }
551 fd = ret;
552 goto error;
553 }
554
555 error:
556 return fd;
557 }
558
559 /*
560 * On some filesystems (e.g. nfs), mkdir will validate access rights before
561 * checking for the existence of the path element. This means that on a setup
562 * where "/home/" is a mounted NFS share, and running as an unpriviledged user,
563 * recursively creating a path of the form "/home/my_user/trace/" will fail with
564 * EACCES on mkdir("/home", ...).
565 *
566 * Performing a stat(...) on the path to check for existence allows us to
567 * work around this behaviour.
568 */
569 static
570 int mkdir_check_exists(const char *path, mode_t mode)
571 {
572 int ret = 0;
573 struct stat st;
574
575 ret = stat(path, &st);
576 if (ret == 0) {
577 if (S_ISDIR(st.st_mode)) {
578 /* Directory exists, skip. */
579 goto end;
580 } else {
581 /* Exists, but is not a directory. */
582 errno = ENOTDIR;
583 ret = -1;
584 goto end;
585 }
586 }
587
588 /*
589 * Let mkdir handle other errors as the caller expects mkdir
590 * semantics.
591 */
592 ret = mkdir(path, mode);
593 end:
594 return ret;
595 }
596
597 /*
598 * Create directory using the given path and mode.
599 *
600 * On success, return 0 else a negative error code.
601 */
602 LTTNG_HIDDEN
603 int utils_mkdir(const char *path, mode_t mode, int uid, int gid)
604 {
605 int ret;
606
607 if (uid < 0 || gid < 0) {
608 ret = mkdir_check_exists(path, mode);
609 } else {
610 ret = run_as_mkdir(path, mode, uid, gid);
611 }
612 if (ret < 0) {
613 if (errno != EEXIST) {
614 PERROR("mkdir %s, uid %d, gid %d", path ? path : "NULL",
615 uid, gid);
616 } else {
617 ret = 0;
618 }
619 }
620
621 return ret;
622 }
623
624 /*
625 * Internal version of mkdir_recursive. Runs as the current user.
626 * Don't call directly; use utils_mkdir_recursive().
627 *
628 * This function is ominously marked as "unsafe" since it should only
629 * be called by a caller that has transitioned to the uid and gid under which
630 * the directory creation should occur.
631 */
632 LTTNG_HIDDEN
633 int _utils_mkdir_recursive_unsafe(const char *path, mode_t mode)
634 {
635 char *p, tmp[PATH_MAX];
636 size_t len;
637 int ret;
638
639 assert(path);
640
641 ret = snprintf(tmp, sizeof(tmp), "%s", path);
642 if (ret < 0) {
643 PERROR("snprintf mkdir");
644 goto error;
645 }
646
647 len = ret;
648 if (tmp[len - 1] == '/') {
649 tmp[len - 1] = 0;
650 }
651
652 for (p = tmp + 1; *p; p++) {
653 if (*p == '/') {
654 *p = 0;
655 if (tmp[strlen(tmp) - 1] == '.' &&
656 tmp[strlen(tmp) - 2] == '.' &&
657 tmp[strlen(tmp) - 3] == '/') {
658 ERR("Using '/../' is not permitted in the trace path (%s)",
659 tmp);
660 ret = -1;
661 goto error;
662 }
663 ret = mkdir_check_exists(tmp, mode);
664 if (ret < 0) {
665 if (errno != EACCES) {
666 PERROR("mkdir recursive");
667 ret = -errno;
668 goto error;
669 }
670 }
671 *p = '/';
672 }
673 }
674
675 ret = mkdir_check_exists(tmp, mode);
676 if (ret < 0) {
677 PERROR("mkdir recursive last element");
678 ret = -errno;
679 }
680
681 error:
682 return ret;
683 }
684
685 /*
686 * Recursively create directory using the given path and mode, under the
687 * provided uid and gid.
688 *
689 * On success, return 0 else a negative error code.
690 */
691 LTTNG_HIDDEN
692 int utils_mkdir_recursive(const char *path, mode_t mode, int uid, int gid)
693 {
694 int ret;
695
696 if (uid < 0 || gid < 0) {
697 /* Run as current user. */
698 ret = _utils_mkdir_recursive_unsafe(path, mode);
699 } else {
700 ret = run_as_mkdir_recursive(path, mode, uid, gid);
701 }
702 if (ret < 0) {
703 PERROR("mkdir %s, uid %d, gid %d", path ? path : "NULL",
704 uid, gid);
705 }
706
707 return ret;
708 }
709
710 /*
711 * path is the output parameter. It needs to be PATH_MAX len.
712 *
713 * Return 0 on success or else a negative value.
714 */
715 static int utils_stream_file_name(char *path,
716 const char *path_name, const char *file_name,
717 uint64_t size, uint64_t count,
718 const char *suffix)
719 {
720 int ret;
721 char full_path[PATH_MAX];
722 char *path_name_suffix = NULL;
723 char *extra = NULL;
724
725 ret = snprintf(full_path, sizeof(full_path), "%s/%s",
726 path_name, file_name);
727 if (ret < 0) {
728 PERROR("snprintf create output file");
729 goto error;
730 }
731
732 /* Setup extra string if suffix or/and a count is needed. */
733 if (size > 0 && suffix) {
734 ret = asprintf(&extra, "_%" PRIu64 "%s", count, suffix);
735 } else if (size > 0) {
736 ret = asprintf(&extra, "_%" PRIu64, count);
737 } else if (suffix) {
738 ret = asprintf(&extra, "%s", suffix);
739 }
740 if (ret < 0) {
741 PERROR("Allocating extra string to name");
742 goto error;
743 }
744
745 /*
746 * If we split the trace in multiple files, we have to add the count at
747 * the end of the tracefile name.
748 */
749 if (extra) {
750 ret = asprintf(&path_name_suffix, "%s%s", full_path, extra);
751 if (ret < 0) {
752 PERROR("Allocating path name with extra string");
753 goto error_free_suffix;
754 }
755 strncpy(path, path_name_suffix, PATH_MAX - 1);
756 path[PATH_MAX - 1] = '\0';
757 } else {
758 strncpy(path, full_path, PATH_MAX - 1);
759 }
760 path[PATH_MAX - 1] = '\0';
761 ret = 0;
762
763 free(path_name_suffix);
764 error_free_suffix:
765 free(extra);
766 error:
767 return ret;
768 }
769
770 /*
771 * Create the stream file on disk.
772 *
773 * Return 0 on success or else a negative value.
774 */
775 LTTNG_HIDDEN
776 int utils_create_stream_file(const char *path_name, char *file_name, uint64_t size,
777 uint64_t count, int uid, int gid, char *suffix)
778 {
779 int ret, flags, mode;
780 char path[PATH_MAX];
781
782 ret = utils_stream_file_name(path, path_name, file_name,
783 size, count, suffix);
784 if (ret < 0) {
785 goto error;
786 }
787
788 /*
789 * With the session rotation feature on the relay, we might need to seek
790 * and truncate a tracefile, so we need read and write access.
791 */
792 flags = O_RDWR | O_CREAT | O_TRUNC;
793 /* Open with 660 mode */
794 mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
795
796 if (uid < 0 || gid < 0) {
797 ret = open(path, flags, mode);
798 } else {
799 ret = run_as_open(path, flags, mode, uid, gid);
800 }
801 if (ret < 0) {
802 PERROR("open stream path %s", path);
803 }
804 error:
805 return ret;
806 }
807
808 /*
809 * Unlink the stream tracefile from disk.
810 *
811 * Return 0 on success or else a negative value.
812 */
813 LTTNG_HIDDEN
814 int utils_unlink_stream_file(const char *path_name, char *file_name, uint64_t size,
815 uint64_t count, int uid, int gid, char *suffix)
816 {
817 int ret;
818 char path[PATH_MAX];
819
820 ret = utils_stream_file_name(path, path_name, file_name,
821 size, count, suffix);
822 if (ret < 0) {
823 goto error;
824 }
825 if (uid < 0 || gid < 0) {
826 ret = unlink(path);
827 } else {
828 ret = run_as_unlink(path, uid, gid);
829 }
830 if (ret < 0) {
831 goto error;
832 }
833 error:
834 DBG("utils_unlink_stream_file %s returns %d", path, ret);
835 return ret;
836 }
837
838 /*
839 * Change the output tracefile according to the given size and count The
840 * new_count pointer is set during this operation.
841 *
842 * From the consumer, the stream lock MUST be held before calling this function
843 * because we are modifying the stream status.
844 *
845 * Return 0 on success or else a negative value.
846 */
847 LTTNG_HIDDEN
848 int utils_rotate_stream_file(char *path_name, char *file_name, uint64_t size,
849 uint64_t count, int uid, int gid, int out_fd, uint64_t *new_count,
850 int *stream_fd)
851 {
852 int ret;
853
854 assert(stream_fd);
855
856 ret = close(out_fd);
857 if (ret < 0) {
858 PERROR("Closing tracefile");
859 goto error;
860 }
861 *stream_fd = -1;
862
863 if (count > 0) {
864 /*
865 * In tracefile rotation, for the relay daemon we need
866 * to unlink the old file if present, because it may
867 * still be open in reading by the live thread, and we
868 * need to ensure that we do not overwrite the content
869 * between get_index and get_packet. Since we have no
870 * way to verify integrity of the data content compared
871 * to the associated index, we need to ensure the reader
872 * has exclusive access to the file content, and that
873 * the open of the data file is performed in get_index.
874 * Unlinking the old file rather than overwriting it
875 * achieves this.
876 */
877 if (new_count) {
878 *new_count = (*new_count + 1) % count;
879 }
880 ret = utils_unlink_stream_file(path_name, file_name, size,
881 new_count ? *new_count : 0, uid, gid, 0);
882 if (ret < 0 && errno != ENOENT) {
883 goto error;
884 }
885 } else {
886 if (new_count) {
887 (*new_count)++;
888 }
889 }
890
891 ret = utils_create_stream_file(path_name, file_name, size,
892 new_count ? *new_count : 0, uid, gid, 0);
893 if (ret < 0) {
894 goto error;
895 }
896 *stream_fd = ret;
897
898 /* Success. */
899 ret = 0;
900
901 error:
902 return ret;
903 }
904
905
906 /**
907 * Parse a string that represents a size in human readable format. It
908 * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
909 *
910 * The suffix multiply the integer by:
911 * 'k': 1024
912 * 'M': 1024^2
913 * 'G': 1024^3
914 *
915 * @param str The string to parse.
916 * @param size Pointer to a uint64_t that will be filled with the
917 * resulting size.
918 *
919 * @return 0 on success, -1 on failure.
920 */
921 LTTNG_HIDDEN
922 int utils_parse_size_suffix(const char * const str, uint64_t * const size)
923 {
924 int ret;
925 uint64_t base_size;
926 long shift = 0;
927 const char *str_end;
928 char *num_end;
929
930 if (!str) {
931 DBG("utils_parse_size_suffix: received a NULL string.");
932 ret = -1;
933 goto end;
934 }
935
936 /* strtoull will accept a negative number, but we don't want to. */
937 if (strchr(str, '-') != NULL) {
938 DBG("utils_parse_size_suffix: invalid size string, should not contain '-'.");
939 ret = -1;
940 goto end;
941 }
942
943 /* str_end will point to the \0 */
944 str_end = str + strlen(str);
945 errno = 0;
946 base_size = strtoull(str, &num_end, 0);
947 if (errno != 0) {
948 PERROR("utils_parse_size_suffix strtoull");
949 ret = -1;
950 goto end;
951 }
952
953 if (num_end == str) {
954 /* strtoull parsed nothing, not good. */
955 DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
956 ret = -1;
957 goto end;
958 }
959
960 /* Check if a prefix is present. */
961 switch (*num_end) {
962 case 'G':
963 shift = GIBI_LOG2;
964 num_end++;
965 break;
966 case 'M': /* */
967 shift = MEBI_LOG2;
968 num_end++;
969 break;
970 case 'K':
971 case 'k':
972 shift = KIBI_LOG2;
973 num_end++;
974 break;
975 case '\0':
976 break;
977 default:
978 DBG("utils_parse_size_suffix: invalid suffix.");
979 ret = -1;
980 goto end;
981 }
982
983 /* Check for garbage after the valid input. */
984 if (num_end != str_end) {
985 DBG("utils_parse_size_suffix: Garbage after size string.");
986 ret = -1;
987 goto end;
988 }
989
990 *size = base_size << shift;
991
992 /* Check for overflow */
993 if ((*size >> shift) != base_size) {
994 DBG("utils_parse_size_suffix: oops, overflow detected.");
995 ret = -1;
996 goto end;
997 }
998
999 ret = 0;
1000 end:
1001 return ret;
1002 }
1003
1004 /**
1005 * Parse a string that represents a time in human readable format. It
1006 * supports decimal integers suffixed by 's', 'u', 'm', 'us', and 'ms'.
1007 *
1008 * The suffix multiply the integer by:
1009 * 'u'/'us': 1
1010 * 'm'/'ms': 1000
1011 * 's': 1000000
1012 *
1013 * Note that unit-less numbers are assumed to be microseconds.
1014 *
1015 * @param str The string to parse, assumed to be NULL-terminated.
1016 * @param time_us Pointer to a uint64_t that will be filled with the
1017 * resulting time in microseconds.
1018 *
1019 * @return 0 on success, -1 on failure.
1020 */
1021 LTTNG_HIDDEN
1022 int utils_parse_time_suffix(char const * const str, uint64_t * const time_us)
1023 {
1024 int ret;
1025 uint64_t base_time;
1026 long multiplier = 1;
1027 const char *str_end;
1028 char *num_end;
1029
1030 if (!str) {
1031 DBG("utils_parse_time_suffix: received a NULL string.");
1032 ret = -1;
1033 goto end;
1034 }
1035
1036 /* strtoull will accept a negative number, but we don't want to. */
1037 if (strchr(str, '-') != NULL) {
1038 DBG("utils_parse_time_suffix: invalid time string, should not contain '-'.");
1039 ret = -1;
1040 goto end;
1041 }
1042
1043 /* str_end will point to the \0 */
1044 str_end = str + strlen(str);
1045 errno = 0;
1046 base_time = strtoull(str, &num_end, 10);
1047 if (errno != 0) {
1048 PERROR("utils_parse_time_suffix strtoull on string \"%s\"", str);
1049 ret = -1;
1050 goto end;
1051 }
1052
1053 if (num_end == str) {
1054 /* strtoull parsed nothing, not good. */
1055 DBG("utils_parse_time_suffix: strtoull had nothing good to parse.");
1056 ret = -1;
1057 goto end;
1058 }
1059
1060 /* Check if a prefix is present. */
1061 switch (*num_end) {
1062 case 'u':
1063 multiplier = 1;
1064 /* Skip another letter in the 'us' case. */
1065 num_end += (*(num_end + 1) == 's') ? 2 : 1;
1066 break;
1067 case 'm':
1068 multiplier = 1000;
1069 /* Skip another letter in the 'ms' case. */
1070 num_end += (*(num_end + 1) == 's') ? 2 : 1;
1071 break;
1072 case 's':
1073 multiplier = 1000000;
1074 num_end++;
1075 break;
1076 case '\0':
1077 break;
1078 default:
1079 DBG("utils_parse_time_suffix: invalid suffix.");
1080 ret = -1;
1081 goto end;
1082 }
1083
1084 /* Check for garbage after the valid input. */
1085 if (num_end != str_end) {
1086 DBG("utils_parse_time_suffix: Garbage after time string.");
1087 ret = -1;
1088 goto end;
1089 }
1090
1091 *time_us = base_time * multiplier;
1092
1093 /* Check for overflow */
1094 if ((*time_us / multiplier) != base_time) {
1095 DBG("utils_parse_time_suffix: oops, overflow detected.");
1096 ret = -1;
1097 goto end;
1098 }
1099
1100 ret = 0;
1101 end:
1102 return ret;
1103 }
1104
1105 /*
1106 * fls: returns the position of the most significant bit.
1107 * Returns 0 if no bit is set, else returns the position of the most
1108 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
1109 */
1110 #if defined(__i386) || defined(__x86_64)
1111 static inline unsigned int fls_u32(uint32_t x)
1112 {
1113 int r;
1114
1115 asm("bsrl %1,%0\n\t"
1116 "jnz 1f\n\t"
1117 "movl $-1,%0\n\t"
1118 "1:\n\t"
1119 : "=r" (r) : "rm" (x));
1120 return r + 1;
1121 }
1122 #define HAS_FLS_U32
1123 #endif
1124
1125 #if defined(__x86_64)
1126 static inline
1127 unsigned int fls_u64(uint64_t x)
1128 {
1129 long r;
1130
1131 asm("bsrq %1,%0\n\t"
1132 "jnz 1f\n\t"
1133 "movq $-1,%0\n\t"
1134 "1:\n\t"
1135 : "=r" (r) : "rm" (x));
1136 return r + 1;
1137 }
1138 #define HAS_FLS_U64
1139 #endif
1140
1141 #ifndef HAS_FLS_U64
1142 static __attribute__((unused))
1143 unsigned int fls_u64(uint64_t x)
1144 {
1145 unsigned int r = 64;
1146
1147 if (!x)
1148 return 0;
1149
1150 if (!(x & 0xFFFFFFFF00000000ULL)) {
1151 x <<= 32;
1152 r -= 32;
1153 }
1154 if (!(x & 0xFFFF000000000000ULL)) {
1155 x <<= 16;
1156 r -= 16;
1157 }
1158 if (!(x & 0xFF00000000000000ULL)) {
1159 x <<= 8;
1160 r -= 8;
1161 }
1162 if (!(x & 0xF000000000000000ULL)) {
1163 x <<= 4;
1164 r -= 4;
1165 }
1166 if (!(x & 0xC000000000000000ULL)) {
1167 x <<= 2;
1168 r -= 2;
1169 }
1170 if (!(x & 0x8000000000000000ULL)) {
1171 x <<= 1;
1172 r -= 1;
1173 }
1174 return r;
1175 }
1176 #endif
1177
1178 #ifndef HAS_FLS_U32
1179 static __attribute__((unused)) unsigned int fls_u32(uint32_t x)
1180 {
1181 unsigned int r = 32;
1182
1183 if (!x) {
1184 return 0;
1185 }
1186 if (!(x & 0xFFFF0000U)) {
1187 x <<= 16;
1188 r -= 16;
1189 }
1190 if (!(x & 0xFF000000U)) {
1191 x <<= 8;
1192 r -= 8;
1193 }
1194 if (!(x & 0xF0000000U)) {
1195 x <<= 4;
1196 r -= 4;
1197 }
1198 if (!(x & 0xC0000000U)) {
1199 x <<= 2;
1200 r -= 2;
1201 }
1202 if (!(x & 0x80000000U)) {
1203 x <<= 1;
1204 r -= 1;
1205 }
1206 return r;
1207 }
1208 #endif
1209
1210 /*
1211 * Return the minimum order for which x <= (1UL << order).
1212 * Return -1 if x is 0.
1213 */
1214 LTTNG_HIDDEN
1215 int utils_get_count_order_u32(uint32_t x)
1216 {
1217 if (!x) {
1218 return -1;
1219 }
1220
1221 return fls_u32(x - 1);
1222 }
1223
1224 /*
1225 * Return the minimum order for which x <= (1UL << order).
1226 * Return -1 if x is 0.
1227 */
1228 LTTNG_HIDDEN
1229 int utils_get_count_order_u64(uint64_t x)
1230 {
1231 if (!x) {
1232 return -1;
1233 }
1234
1235 return fls_u64(x - 1);
1236 }
1237
1238 /**
1239 * Obtain the value of LTTNG_HOME environment variable, if exists.
1240 * Otherwise returns the value of HOME.
1241 */
1242 LTTNG_HIDDEN
1243 char *utils_get_home_dir(void)
1244 {
1245 char *val = NULL;
1246 struct passwd *pwd;
1247
1248 val = lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
1249 if (val != NULL) {
1250 goto end;
1251 }
1252 val = lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
1253 if (val != NULL) {
1254 goto end;
1255 }
1256
1257 /* Fallback on the password file entry. */
1258 pwd = getpwuid(getuid());
1259 if (!pwd) {
1260 goto end;
1261 }
1262 val = pwd->pw_dir;
1263
1264 DBG3("Home directory is '%s'", val);
1265
1266 end:
1267 return val;
1268 }
1269
1270 /**
1271 * Get user's home directory. Dynamically allocated, must be freed
1272 * by the caller.
1273 */
1274 LTTNG_HIDDEN
1275 char *utils_get_user_home_dir(uid_t uid)
1276 {
1277 struct passwd pwd;
1278 struct passwd *result;
1279 char *home_dir = NULL;
1280 char *buf = NULL;
1281 long buflen;
1282 int ret;
1283
1284 buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
1285 if (buflen == -1) {
1286 goto end;
1287 }
1288 retry:
1289 buf = zmalloc(buflen);
1290 if (!buf) {
1291 goto end;
1292 }
1293
1294 ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
1295 if (ret || !result) {
1296 if (ret == ERANGE) {
1297 free(buf);
1298 buflen *= 2;
1299 goto retry;
1300 }
1301 goto end;
1302 }
1303
1304 home_dir = strdup(pwd.pw_dir);
1305 end:
1306 free(buf);
1307 return home_dir;
1308 }
1309
1310 /*
1311 * With the given format, fill dst with the time of len maximum siz.
1312 *
1313 * Return amount of bytes set in the buffer or else 0 on error.
1314 */
1315 LTTNG_HIDDEN
1316 size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
1317 {
1318 size_t ret;
1319 time_t rawtime;
1320 struct tm *timeinfo;
1321
1322 assert(format);
1323 assert(dst);
1324
1325 /* Get date and time for session path */
1326 time(&rawtime);
1327 timeinfo = localtime(&rawtime);
1328 ret = strftime(dst, len, format, timeinfo);
1329 if (ret == 0) {
1330 ERR("Unable to strftime with format %s at dst %p of len %zu", format,
1331 dst, len);
1332 }
1333
1334 return ret;
1335 }
1336
1337 /*
1338 * Return the group ID matching name, else 0 if it cannot be found.
1339 */
1340 LTTNG_HIDDEN
1341 gid_t utils_get_group_id(const char *name)
1342 {
1343 struct group *grp;
1344
1345 grp = getgrnam(name);
1346 if (!grp) {
1347 static volatile int warn_once;
1348
1349 if (!warn_once) {
1350 WARN("No tracing group detected");
1351 warn_once = 1;
1352 }
1353 return 0;
1354 }
1355 return grp->gr_gid;
1356 }
1357
1358 /*
1359 * Return a newly allocated option string. This string is to be used as the
1360 * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
1361 * of elements in the long_options array. Returns NULL if the string's
1362 * allocation fails.
1363 */
1364 LTTNG_HIDDEN
1365 char *utils_generate_optstring(const struct option *long_options,
1366 size_t opt_count)
1367 {
1368 int i;
1369 size_t string_len = opt_count, str_pos = 0;
1370 char *optstring;
1371
1372 /*
1373 * Compute the necessary string length. One letter per option, two when an
1374 * argument is necessary, and a trailing NULL.
1375 */
1376 for (i = 0; i < opt_count; i++) {
1377 string_len += long_options[i].has_arg ? 1 : 0;
1378 }
1379
1380 optstring = zmalloc(string_len);
1381 if (!optstring) {
1382 goto end;
1383 }
1384
1385 for (i = 0; i < opt_count; i++) {
1386 if (!long_options[i].name) {
1387 /* Got to the trailing NULL element */
1388 break;
1389 }
1390
1391 if (long_options[i].val != '\0') {
1392 optstring[str_pos++] = (char) long_options[i].val;
1393 if (long_options[i].has_arg) {
1394 optstring[str_pos++] = ':';
1395 }
1396 }
1397 }
1398
1399 end:
1400 return optstring;
1401 }
1402
1403 /*
1404 * Try to remove a hierarchy of empty directories, recursively. Don't unlink
1405 * any file. Try to rmdir any empty directory within the hierarchy.
1406 */
1407 LTTNG_HIDDEN
1408 int utils_recursive_rmdir(const char *path)
1409 {
1410 DIR *dir;
1411 size_t path_len;
1412 int dir_fd, ret = 0, closeret, is_empty = 1;
1413 struct dirent *entry;
1414
1415 /* Open directory */
1416 dir = opendir(path);
1417 if (!dir) {
1418 PERROR("Cannot open '%s' path", path);
1419 return -1;
1420 }
1421 dir_fd = lttng_dirfd(dir);
1422 if (dir_fd < 0) {
1423 PERROR("lttng_dirfd");
1424 return -1;
1425 }
1426
1427 path_len = strlen(path);
1428 while ((entry = readdir(dir))) {
1429 struct stat st;
1430 size_t name_len;
1431 char filename[PATH_MAX];
1432
1433 if (!strcmp(entry->d_name, ".")
1434 || !strcmp(entry->d_name, "..")) {
1435 continue;
1436 }
1437
1438 name_len = strlen(entry->d_name);
1439 if (path_len + name_len + 2 > sizeof(filename)) {
1440 ERR("Failed to remove file: path name too long (%s/%s)",
1441 path, entry->d_name);
1442 continue;
1443 }
1444 if (snprintf(filename, sizeof(filename), "%s/%s",
1445 path, entry->d_name) < 0) {
1446 ERR("Failed to format path.");
1447 continue;
1448 }
1449
1450 if (stat(filename, &st)) {
1451 PERROR("stat");
1452 continue;
1453 }
1454
1455 if (S_ISDIR(st.st_mode)) {
1456 char subpath[PATH_MAX];
1457
1458 strncpy(subpath, path, PATH_MAX);
1459 subpath[PATH_MAX - 1] = '\0';
1460 strncat(subpath, "/",
1461 PATH_MAX - strlen(subpath) - 1);
1462 strncat(subpath, entry->d_name,
1463 PATH_MAX - strlen(subpath) - 1);
1464 if (utils_recursive_rmdir(subpath)) {
1465 is_empty = 0;
1466 }
1467 } else if (S_ISREG(st.st_mode)) {
1468 is_empty = 0;
1469 } else {
1470 ret = -EINVAL;
1471 goto end;
1472 }
1473 }
1474 end:
1475 closeret = closedir(dir);
1476 if (closeret) {
1477 PERROR("closedir");
1478 }
1479 if (is_empty) {
1480 DBG3("Attempting rmdir %s", path);
1481 ret = rmdir(path);
1482 }
1483 return ret;
1484 }
1485
1486 LTTNG_HIDDEN
1487 int utils_truncate_stream_file(int fd, off_t length)
1488 {
1489 int ret;
1490
1491 ret = ftruncate(fd, length);
1492 if (ret < 0) {
1493 PERROR("ftruncate");
1494 goto end;
1495 }
1496 ret = lseek(fd, length, SEEK_SET);
1497 if (ret < 0) {
1498 PERROR("lseek");
1499 goto end;
1500 }
1501 end:
1502 return ret;
1503 }
1504
1505 static const char *get_man_bin_path(void)
1506 {
1507 char *env_man_path = lttng_secure_getenv(DEFAULT_MAN_BIN_PATH_ENV);
1508
1509 if (env_man_path) {
1510 return env_man_path;
1511 }
1512
1513 return DEFAULT_MAN_BIN_PATH;
1514 }
1515
1516 LTTNG_HIDDEN
1517 int utils_show_help(int section, const char *page_name,
1518 const char *help_msg)
1519 {
1520 char section_string[8];
1521 const char *man_bin_path = get_man_bin_path();
1522 int ret = 0;
1523
1524 if (help_msg) {
1525 printf("%s", help_msg);
1526 goto end;
1527 }
1528
1529 /* Section integer -> section string */
1530 ret = sprintf(section_string, "%d", section);
1531 assert(ret > 0 && ret < 8);
1532
1533 /*
1534 * Execute man pager.
1535 *
1536 * We provide -M to man here because LTTng-tools can
1537 * be installed outside /usr, in which case its man pages are
1538 * not located in the default /usr/share/man directory.
1539 */
1540 ret = execlp(man_bin_path, "man", "-M", MANPATH,
1541 section_string, page_name, NULL);
1542
1543 end:
1544 return ret;
1545 }
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