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