dynamic-array: fix documentation of lttng_dynamic_pointer_array_get_pointer
[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/readwrite.h>
37 #include <common/runas.h>
38 #include <common/compat/getenv.h>
39 #include <common/compat/string.h>
40 #include <common/compat/dirent.h>
41 #include <common/compat/directory-handle.h>
42 #include <common/dynamic-buffer.h>
43 #include <common/string-utils/format.h>
44 #include <lttng/constant.h>
45
46 #include "utils.h"
47 #include "defaults.h"
48 #include "time.h"
49
50 #define PROC_MEMINFO_PATH "/proc/meminfo"
51 #define PROC_MEMINFO_MEMAVAILABLE_LINE "MemAvailable:"
52 #define PROC_MEMINFO_MEMTOTAL_LINE "MemTotal:"
53
54 /* The length of the longest field of `/proc/meminfo`. */
55 #define PROC_MEMINFO_FIELD_MAX_NAME_LEN 20
56
57 #if (PROC_MEMINFO_FIELD_MAX_NAME_LEN == 20)
58 #define MAX_NAME_LEN_SCANF_IS_A_BROKEN_API "19"
59 #else
60 #error MAX_NAME_LEN_SCANF_IS_A_BROKEN_API must be updated to match (PROC_MEMINFO_FIELD_MAX_NAME_LEN - 1)
61 #endif
62
63 /*
64 * Return a partial realpath(3) of the path even if the full path does not
65 * exist. For instance, with /tmp/test1/test2/test3, if test2/ does not exist
66 * but the /tmp/test1 does, the real path for /tmp/test1 is concatened with
67 * /test2/test3 then returned. In normal time, realpath(3) fails if the end
68 * point directory does not exist.
69 * In case resolved_path is NULL, the string returned was allocated in the
70 * function and thus need to be freed by the caller. The size argument allows
71 * to specify the size of the resolved_path argument if given, or the size to
72 * allocate.
73 */
74 LTTNG_HIDDEN
75 char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
76 {
77 char *cut_path = NULL, *try_path = NULL, *try_path_prev = NULL;
78 const char *next, *prev, *end;
79
80 /* Safety net */
81 if (path == NULL) {
82 goto error;
83 }
84
85 /*
86 * Identify the end of the path, we don't want to treat the
87 * last char if it is a '/', we will just keep it on the side
88 * to be added at the end, and return a value coherent with
89 * the path given as argument
90 */
91 end = path + strlen(path);
92 if (*(end-1) == '/') {
93 end--;
94 }
95
96 /* Initiate the values of the pointers before looping */
97 next = path;
98 prev = next;
99 /* Only to ensure try_path is not NULL to enter the while */
100 try_path = (char *)next;
101
102 /* Resolve the canonical path of the first part of the path */
103 while (try_path != NULL && next != end) {
104 char *try_path_buf = NULL;
105
106 /*
107 * If there is not any '/' left, we want to try with
108 * the full path
109 */
110 next = strpbrk(next + 1, "/");
111 if (next == NULL) {
112 next = end;
113 }
114
115 /* Cut the part we will be trying to resolve */
116 cut_path = lttng_strndup(path, next - path);
117 if (cut_path == NULL) {
118 PERROR("lttng_strndup");
119 goto error;
120 }
121
122 try_path_buf = zmalloc(LTTNG_PATH_MAX);
123 if (!try_path_buf) {
124 PERROR("zmalloc");
125 goto error;
126 }
127
128 /* Try to resolve this part */
129 try_path = realpath((char *) cut_path, try_path_buf);
130 if (try_path == NULL) {
131 free(try_path_buf);
132 /*
133 * There was an error, we just want to be assured it
134 * is linked to an unexistent directory, if it's another
135 * reason, we spawn an error
136 */
137 switch (errno) {
138 case ENOENT:
139 /* Ignore the error */
140 break;
141 default:
142 PERROR("realpath (partial_realpath)");
143 goto error;
144 break;
145 }
146 } else {
147 /* Save the place we are before trying the next step */
148 try_path_buf = NULL;
149 free(try_path_prev);
150 try_path_prev = try_path;
151 prev = next;
152 }
153
154 /* Free the allocated memory */
155 free(cut_path);
156 cut_path = NULL;
157 }
158
159 /* Allocate memory for the resolved path if necessary */
160 if (resolved_path == NULL) {
161 resolved_path = zmalloc(size);
162 if (resolved_path == NULL) {
163 PERROR("zmalloc resolved path");
164 goto error;
165 }
166 }
167
168 /*
169 * If we were able to solve at least partially the path, we can concatenate
170 * what worked and what didn't work
171 */
172 if (try_path_prev != NULL) {
173 /* If we risk to concatenate two '/', we remove one of them */
174 if (try_path_prev[strlen(try_path_prev) - 1] == '/' && prev[0] == '/') {
175 try_path_prev[strlen(try_path_prev) - 1] = '\0';
176 }
177
178 /*
179 * Duplicate the memory used by prev in case resolved_path and
180 * path are pointers for the same memory space
181 */
182 cut_path = strdup(prev);
183 if (cut_path == NULL) {
184 PERROR("strdup");
185 goto error;
186 }
187
188 /* Concatenate the strings */
189 snprintf(resolved_path, size, "%s%s", try_path_prev, cut_path);
190
191 /* Free the allocated memory */
192 free(cut_path);
193 free(try_path_prev);
194 cut_path = NULL;
195 try_path_prev = NULL;
196 /*
197 * Else, we just copy the path in our resolved_path to
198 * return it as is
199 */
200 } else {
201 strncpy(resolved_path, path, size);
202 }
203
204 /* Then we return the 'partially' resolved path */
205 return resolved_path;
206
207 error:
208 free(resolved_path);
209 free(cut_path);
210 free(try_path);
211 if (try_path_prev != try_path) {
212 free(try_path_prev);
213 }
214 return NULL;
215 }
216
217 static
218 int expand_double_slashes_dot_and_dotdot(char *path)
219 {
220 size_t expanded_path_len, path_len;
221 const char *curr_char, *path_last_char, *next_slash, *prev_slash;
222
223 path_len = strlen(path);
224 path_last_char = &path[path_len];
225
226 if (path_len == 0) {
227 goto error;
228 }
229
230 expanded_path_len = 0;
231
232 /* We iterate over the provided path to expand the "//", "../" and "./" */
233 for (curr_char = path; curr_char <= path_last_char; curr_char = next_slash + 1) {
234 /* Find the next forward slash. */
235 size_t curr_token_len;
236
237 if (curr_char == path_last_char) {
238 expanded_path_len++;
239 break;
240 }
241
242 next_slash = memchr(curr_char, '/', path_last_char - curr_char);
243 if (next_slash == NULL) {
244 /* Reached the end of the provided path. */
245 next_slash = path_last_char;
246 }
247
248 /* Compute how long is the previous token. */
249 curr_token_len = next_slash - curr_char;
250 switch(curr_token_len) {
251 case 0:
252 /*
253 * The pointer has not move meaning that curr_char is
254 * pointing to a slash. It that case there is no token
255 * to copy, so continue the iteration to find the next
256 * token
257 */
258 continue;
259 case 1:
260 /*
261 * The pointer moved 1 character. Check if that
262 * character is a dot ('.'), if it is: omit it, else
263 * copy the token to the normalized path.
264 */
265 if (curr_char[0] == '.') {
266 continue;
267 }
268 break;
269 case 2:
270 /*
271 * The pointer moved 2 characters. Check if these
272 * characters are double dots ('..'). If that is the
273 * case, we need to remove the last token of the
274 * normalized path.
275 */
276 if (curr_char[0] == '.' && curr_char[1] == '.') {
277 /*
278 * Find the previous path component by
279 * using the memrchr function to find the
280 * previous forward slash and substract that
281 * len to the resulting path.
282 */
283 prev_slash = lttng_memrchr(path, '/', expanded_path_len);
284 /*
285 * If prev_slash is NULL, we reached the
286 * beginning of the path. We can't go back any
287 * further.
288 */
289 if (prev_slash != NULL) {
290 expanded_path_len = prev_slash - path;
291 }
292 continue;
293 }
294 break;
295 default:
296 break;
297 }
298
299 /*
300 * Copy the current token which is neither a '.' nor a '..'.
301 */
302 path[expanded_path_len++] = '/';
303 memcpy(&path[expanded_path_len], curr_char, curr_token_len);
304 expanded_path_len += curr_token_len;
305 }
306
307 if (expanded_path_len == 0) {
308 path[expanded_path_len++] = '/';
309 }
310
311 path[expanded_path_len] = '\0';
312 return 0;
313 error:
314 return -1;
315 }
316
317 /*
318 * Make a full resolution of the given path even if it doesn't exist.
319 * This function uses the utils_partial_realpath function to resolve
320 * symlinks and relatives paths at the start of the string, and
321 * implements functionnalities to resolve the './' and '../' strings
322 * in the middle of a path. This function is only necessary because
323 * realpath(3) does not accept to resolve unexistent paths.
324 * The returned string was allocated in the function, it is thus of
325 * the responsibility of the caller to free this memory.
326 */
327 static
328 char *_utils_expand_path(const char *path, bool keep_symlink)
329 {
330 int ret;
331 char *absolute_path = NULL;
332 char *last_token;
333 bool is_dot, is_dotdot;
334
335 /* Safety net */
336 if (path == NULL) {
337 goto error;
338 }
339
340 /* Allocate memory for the absolute_path */
341 absolute_path = zmalloc(LTTNG_PATH_MAX);
342 if (absolute_path == NULL) {
343 PERROR("zmalloc expand path");
344 goto error;
345 }
346
347 if (path[0] == '/') {
348 ret = lttng_strncpy(absolute_path, path, LTTNG_PATH_MAX);
349 if (ret) {
350 ERR("Path exceeds maximal size of %i bytes", LTTNG_PATH_MAX);
351 goto error;
352 }
353 } else {
354 /*
355 * This is a relative path. We need to get the present working
356 * directory and start the path walk from there.
357 */
358 char current_working_dir[LTTNG_PATH_MAX];
359 char *cwd_ret;
360
361 cwd_ret = getcwd(current_working_dir, sizeof(current_working_dir));
362 if (!cwd_ret) {
363 goto error;
364 }
365 /*
366 * Get the number of character in the CWD and allocate an array
367 * to can hold it and the path provided by the caller.
368 */
369 ret = snprintf(absolute_path, LTTNG_PATH_MAX, "%s/%s",
370 current_working_dir, path);
371 if (ret >= LTTNG_PATH_MAX) {
372 ERR("Concatenating current working directory %s and path %s exceeds maximal size of %i bytes",
373 current_working_dir, path, LTTNG_PATH_MAX);
374 goto error;
375 }
376 }
377
378 if (keep_symlink) {
379 /* Resolve partially our path */
380 absolute_path = utils_partial_realpath(absolute_path,
381 absolute_path, LTTNG_PATH_MAX);
382 if (!absolute_path) {
383 goto error;
384 }
385 }
386
387 ret = expand_double_slashes_dot_and_dotdot(absolute_path);
388 if (ret) {
389 goto error;
390 }
391
392 /* Identify the last token */
393 last_token = strrchr(absolute_path, '/');
394
395 /* Verify that this token is not a relative path */
396 is_dotdot = (strcmp(last_token, "/..") == 0);
397 is_dot = (strcmp(last_token, "/.") == 0);
398
399 /* If it is, take action */
400 if (is_dot || is_dotdot) {
401 /* For both, remove this token */
402 *last_token = '\0';
403
404 /* If it was a reference to parent directory, go back one more time */
405 if (is_dotdot) {
406 last_token = strrchr(absolute_path, '/');
407
408 /* If there was only one level left, we keep the first '/' */
409 if (last_token == absolute_path) {
410 last_token++;
411 }
412
413 *last_token = '\0';
414 }
415 }
416
417 return absolute_path;
418
419 error:
420 free(absolute_path);
421 return NULL;
422 }
423 LTTNG_HIDDEN
424 char *utils_expand_path(const char *path)
425 {
426 return _utils_expand_path(path, true);
427 }
428
429 LTTNG_HIDDEN
430 char *utils_expand_path_keep_symlink(const char *path)
431 {
432 return _utils_expand_path(path, false);
433 }
434 /*
435 * Create a pipe in dst.
436 */
437 LTTNG_HIDDEN
438 int utils_create_pipe(int *dst)
439 {
440 int ret;
441
442 if (dst == NULL) {
443 return -1;
444 }
445
446 ret = pipe(dst);
447 if (ret < 0) {
448 PERROR("create pipe");
449 }
450
451 return ret;
452 }
453
454 /*
455 * Create pipe and set CLOEXEC flag to both fd.
456 *
457 * Make sure the pipe opened by this function are closed at some point. Use
458 * utils_close_pipe().
459 */
460 LTTNG_HIDDEN
461 int utils_create_pipe_cloexec(int *dst)
462 {
463 int ret, i;
464
465 if (dst == NULL) {
466 return -1;
467 }
468
469 ret = utils_create_pipe(dst);
470 if (ret < 0) {
471 goto error;
472 }
473
474 for (i = 0; i < 2; i++) {
475 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
476 if (ret < 0) {
477 PERROR("fcntl pipe cloexec");
478 goto error;
479 }
480 }
481
482 error:
483 return ret;
484 }
485
486 /*
487 * Create pipe and set fd flags to FD_CLOEXEC and O_NONBLOCK.
488 *
489 * Make sure the pipe opened by this function are closed at some point. Use
490 * utils_close_pipe(). Using pipe() and fcntl rather than pipe2() to
491 * support OSes other than Linux 2.6.23+.
492 */
493 LTTNG_HIDDEN
494 int utils_create_pipe_cloexec_nonblock(int *dst)
495 {
496 int ret, i;
497
498 if (dst == NULL) {
499 return -1;
500 }
501
502 ret = utils_create_pipe(dst);
503 if (ret < 0) {
504 goto error;
505 }
506
507 for (i = 0; i < 2; i++) {
508 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
509 if (ret < 0) {
510 PERROR("fcntl pipe cloexec");
511 goto error;
512 }
513 /*
514 * Note: we override any flag that could have been
515 * previously set on the fd.
516 */
517 ret = fcntl(dst[i], F_SETFL, O_NONBLOCK);
518 if (ret < 0) {
519 PERROR("fcntl pipe nonblock");
520 goto error;
521 }
522 }
523
524 error:
525 return ret;
526 }
527
528 /*
529 * Close both read and write side of the pipe.
530 */
531 LTTNG_HIDDEN
532 void utils_close_pipe(int *src)
533 {
534 int i, ret;
535
536 if (src == NULL) {
537 return;
538 }
539
540 for (i = 0; i < 2; i++) {
541 /* Safety check */
542 if (src[i] < 0) {
543 continue;
544 }
545
546 ret = close(src[i]);
547 if (ret) {
548 PERROR("close pipe");
549 }
550 }
551 }
552
553 /*
554 * Create a new string using two strings range.
555 */
556 LTTNG_HIDDEN
557 char *utils_strdupdelim(const char *begin, const char *end)
558 {
559 char *str;
560
561 str = zmalloc(end - begin + 1);
562 if (str == NULL) {
563 PERROR("zmalloc strdupdelim");
564 goto error;
565 }
566
567 memcpy(str, begin, end - begin);
568 str[end - begin] = '\0';
569
570 error:
571 return str;
572 }
573
574 /*
575 * Set CLOEXEC flag to the give file descriptor.
576 */
577 LTTNG_HIDDEN
578 int utils_set_fd_cloexec(int fd)
579 {
580 int ret;
581
582 if (fd < 0) {
583 ret = -EINVAL;
584 goto end;
585 }
586
587 ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
588 if (ret < 0) {
589 PERROR("fcntl cloexec");
590 ret = -errno;
591 }
592
593 end:
594 return ret;
595 }
596
597 /*
598 * Create pid file to the given path and filename.
599 */
600 LTTNG_HIDDEN
601 int utils_create_pid_file(pid_t pid, const char *filepath)
602 {
603 int ret;
604 FILE *fp;
605
606 assert(filepath);
607
608 fp = fopen(filepath, "w");
609 if (fp == NULL) {
610 PERROR("open pid file %s", filepath);
611 ret = -1;
612 goto error;
613 }
614
615 ret = fprintf(fp, "%d\n", (int) pid);
616 if (ret < 0) {
617 PERROR("fprintf pid file");
618 goto error;
619 }
620
621 if (fclose(fp)) {
622 PERROR("fclose");
623 }
624 DBG("Pid %d written in file %s", (int) pid, filepath);
625 ret = 0;
626 error:
627 return ret;
628 }
629
630 /*
631 * Create lock file to the given path and filename.
632 * Returns the associated file descriptor, -1 on error.
633 */
634 LTTNG_HIDDEN
635 int utils_create_lock_file(const char *filepath)
636 {
637 int ret;
638 int fd;
639 struct flock lock;
640
641 assert(filepath);
642
643 memset(&lock, 0, sizeof(lock));
644 fd = open(filepath, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR |
645 S_IRGRP | S_IWGRP);
646 if (fd < 0) {
647 PERROR("open lock file %s", filepath);
648 fd = -1;
649 goto error;
650 }
651
652 /*
653 * Attempt to lock the file. If this fails, there is
654 * already a process using the same lock file running
655 * and we should exit.
656 */
657 lock.l_whence = SEEK_SET;
658 lock.l_type = F_WRLCK;
659
660 ret = fcntl(fd, F_SETLK, &lock);
661 if (ret == -1) {
662 PERROR("fcntl lock file");
663 ERR("Could not get lock file %s, another instance is running.",
664 filepath);
665 if (close(fd)) {
666 PERROR("close lock file");
667 }
668 fd = ret;
669 goto error;
670 }
671
672 error:
673 return fd;
674 }
675
676 /*
677 * Create directory using the given path and mode.
678 *
679 * On success, return 0 else a negative error code.
680 */
681 LTTNG_HIDDEN
682 int utils_mkdir(const char *path, mode_t mode, int uid, int gid)
683 {
684 int ret;
685 struct lttng_directory_handle *handle;
686 const struct lttng_credentials creds = {
687 .uid = (uid_t) uid,
688 .gid = (gid_t) gid,
689 };
690
691 handle = lttng_directory_handle_create(NULL);
692 if (!handle) {
693 ret = -1;
694 goto end;
695 }
696 ret = lttng_directory_handle_create_subdirectory_as_user(
697 handle, path, mode,
698 (uid >= 0 || gid >= 0) ? &creds : NULL);
699 end:
700 lttng_directory_handle_put(handle);
701 return ret;
702 }
703
704 /*
705 * Recursively create directory using the given path and mode, under the
706 * provided uid and gid.
707 *
708 * On success, return 0 else a negative error code.
709 */
710 LTTNG_HIDDEN
711 int utils_mkdir_recursive(const char *path, mode_t mode, int uid, int gid)
712 {
713 int ret;
714 struct lttng_directory_handle *handle;
715 const struct lttng_credentials creds = {
716 .uid = (uid_t) uid,
717 .gid = (gid_t) gid,
718 };
719
720 handle = lttng_directory_handle_create(NULL);
721 if (!handle) {
722 ret = -1;
723 goto end;
724 }
725 ret = lttng_directory_handle_create_subdirectory_recursive_as_user(
726 handle, path, mode,
727 (uid >= 0 || gid >= 0) ? &creds : NULL);
728 end:
729 lttng_directory_handle_put(handle);
730 return ret;
731 }
732
733 /*
734 * out_stream_path is the output parameter.
735 *
736 * Return 0 on success or else a negative value.
737 */
738 LTTNG_HIDDEN
739 int utils_stream_file_path(const char *path_name, const char *file_name,
740 uint64_t size, uint64_t count, const char *suffix,
741 char *out_stream_path, size_t stream_path_len)
742 {
743 int ret;
744 char count_str[MAX_INT_DEC_LEN(count) + 1] = {};
745 const char *path_separator;
746
747 if (path_name && path_name[strlen(path_name) - 1] == '/') {
748 path_separator = "";
749 } else {
750 path_separator = "/";
751 }
752
753 path_name = path_name ? : "";
754 suffix = suffix ? : "";
755 if (size > 0) {
756 ret = snprintf(count_str, sizeof(count_str), "_%" PRIu64,
757 count);
758 assert(ret > 0 && ret < sizeof(count_str));
759 }
760
761 ret = snprintf(out_stream_path, stream_path_len, "%s%s%s%s%s",
762 path_name, path_separator, file_name, count_str,
763 suffix);
764 if (ret < 0 || ret >= stream_path_len) {
765 ERR("Truncation occurred while formatting stream path");
766 ret = -1;
767 } else {
768 ret = 0;
769 }
770 return ret;
771 }
772
773 /**
774 * Parse a string that represents a size in human readable format. It
775 * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
776 *
777 * The suffix multiply the integer by:
778 * 'k': 1024
779 * 'M': 1024^2
780 * 'G': 1024^3
781 *
782 * @param str The string to parse.
783 * @param size Pointer to a uint64_t that will be filled with the
784 * resulting size.
785 *
786 * @return 0 on success, -1 on failure.
787 */
788 LTTNG_HIDDEN
789 int utils_parse_size_suffix(const char * const str, uint64_t * const size)
790 {
791 int ret;
792 uint64_t base_size;
793 long shift = 0;
794 const char *str_end;
795 char *num_end;
796
797 if (!str) {
798 DBG("utils_parse_size_suffix: received a NULL string.");
799 ret = -1;
800 goto end;
801 }
802
803 /* strtoull will accept a negative number, but we don't want to. */
804 if (strchr(str, '-') != NULL) {
805 DBG("utils_parse_size_suffix: invalid size string, should not contain '-'.");
806 ret = -1;
807 goto end;
808 }
809
810 /* str_end will point to the \0 */
811 str_end = str + strlen(str);
812 errno = 0;
813 base_size = strtoull(str, &num_end, 0);
814 if (errno != 0) {
815 PERROR("utils_parse_size_suffix strtoull");
816 ret = -1;
817 goto end;
818 }
819
820 if (num_end == str) {
821 /* strtoull parsed nothing, not good. */
822 DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
823 ret = -1;
824 goto end;
825 }
826
827 /* Check if a prefix is present. */
828 switch (*num_end) {
829 case 'G':
830 shift = GIBI_LOG2;
831 num_end++;
832 break;
833 case 'M': /* */
834 shift = MEBI_LOG2;
835 num_end++;
836 break;
837 case 'K':
838 case 'k':
839 shift = KIBI_LOG2;
840 num_end++;
841 break;
842 case '\0':
843 break;
844 default:
845 DBG("utils_parse_size_suffix: invalid suffix.");
846 ret = -1;
847 goto end;
848 }
849
850 /* Check for garbage after the valid input. */
851 if (num_end != str_end) {
852 DBG("utils_parse_size_suffix: Garbage after size string.");
853 ret = -1;
854 goto end;
855 }
856
857 *size = base_size << shift;
858
859 /* Check for overflow */
860 if ((*size >> shift) != base_size) {
861 DBG("utils_parse_size_suffix: oops, overflow detected.");
862 ret = -1;
863 goto end;
864 }
865
866 ret = 0;
867 end:
868 return ret;
869 }
870
871 /**
872 * Parse a string that represents a time in human readable format. It
873 * supports decimal integers suffixed by:
874 * "us" for microsecond,
875 * "ms" for millisecond,
876 * "s" for second,
877 * "m" for minute,
878 * "h" for hour
879 *
880 * The suffix multiply the integer by:
881 * "us" : 1
882 * "ms" : 1000
883 * "s" : 1000000
884 * "m" : 60000000
885 * "h" : 3600000000
886 *
887 * Note that unit-less numbers are assumed to be microseconds.
888 *
889 * @param str The string to parse, assumed to be NULL-terminated.
890 * @param time_us Pointer to a uint64_t that will be filled with the
891 * resulting time in microseconds.
892 *
893 * @return 0 on success, -1 on failure.
894 */
895 LTTNG_HIDDEN
896 int utils_parse_time_suffix(char const * const str, uint64_t * const time_us)
897 {
898 int ret;
899 uint64_t base_time;
900 uint64_t multiplier = 1;
901 const char *str_end;
902 char *num_end;
903
904 if (!str) {
905 DBG("utils_parse_time_suffix: received a NULL string.");
906 ret = -1;
907 goto end;
908 }
909
910 /* strtoull will accept a negative number, but we don't want to. */
911 if (strchr(str, '-') != NULL) {
912 DBG("utils_parse_time_suffix: invalid time string, should not contain '-'.");
913 ret = -1;
914 goto end;
915 }
916
917 /* str_end will point to the \0 */
918 str_end = str + strlen(str);
919 errno = 0;
920 base_time = strtoull(str, &num_end, 10);
921 if (errno != 0) {
922 PERROR("utils_parse_time_suffix strtoull on string \"%s\"", str);
923 ret = -1;
924 goto end;
925 }
926
927 if (num_end == str) {
928 /* strtoull parsed nothing, not good. */
929 DBG("utils_parse_time_suffix: strtoull had nothing good to parse.");
930 ret = -1;
931 goto end;
932 }
933
934 /* Check if a prefix is present. */
935 switch (*num_end) {
936 case 'u':
937 /*
938 * Microsecond (us)
939 *
940 * Skip the "us" if the string matches the "us" suffix,
941 * otherwise let the check for the end of the string handle
942 * the error reporting.
943 */
944 if (*(num_end + 1) == 's') {
945 num_end += 2;
946 }
947 break;
948 case 'm':
949 if (*(num_end + 1) == 's') {
950 /* Millisecond (ms) */
951 multiplier = USEC_PER_MSEC;
952 /* Skip the 's' */
953 num_end++;
954 } else {
955 /* Minute (m) */
956 multiplier = USEC_PER_MINUTE;
957 }
958 num_end++;
959 break;
960 case 's':
961 /* Second */
962 multiplier = USEC_PER_SEC;
963 num_end++;
964 break;
965 case 'h':
966 /* Hour */
967 multiplier = USEC_PER_HOURS;
968 num_end++;
969 break;
970 case '\0':
971 break;
972 default:
973 DBG("utils_parse_time_suffix: invalid suffix.");
974 ret = -1;
975 goto end;
976 }
977
978 /* Check for garbage after the valid input. */
979 if (num_end != str_end) {
980 DBG("utils_parse_time_suffix: Garbage after time string.");
981 ret = -1;
982 goto end;
983 }
984
985 *time_us = base_time * multiplier;
986
987 /* Check for overflow */
988 if ((*time_us / multiplier) != base_time) {
989 DBG("utils_parse_time_suffix: oops, overflow detected.");
990 ret = -1;
991 goto end;
992 }
993
994 ret = 0;
995 end:
996 return ret;
997 }
998
999 /*
1000 * fls: returns the position of the most significant bit.
1001 * Returns 0 if no bit is set, else returns the position of the most
1002 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
1003 */
1004 #if defined(__i386) || defined(__x86_64)
1005 static inline unsigned int fls_u32(uint32_t x)
1006 {
1007 int r;
1008
1009 asm("bsrl %1,%0\n\t"
1010 "jnz 1f\n\t"
1011 "movl $-1,%0\n\t"
1012 "1:\n\t"
1013 : "=r" (r) : "rm" (x));
1014 return r + 1;
1015 }
1016 #define HAS_FLS_U32
1017 #endif
1018
1019 #if defined(__x86_64) && defined(__LP64__)
1020 static inline
1021 unsigned int fls_u64(uint64_t x)
1022 {
1023 long r;
1024
1025 asm("bsrq %1,%0\n\t"
1026 "jnz 1f\n\t"
1027 "movq $-1,%0\n\t"
1028 "1:\n\t"
1029 : "=r" (r) : "rm" (x));
1030 return r + 1;
1031 }
1032 #define HAS_FLS_U64
1033 #endif
1034
1035 #ifndef HAS_FLS_U64
1036 static __attribute__((unused))
1037 unsigned int fls_u64(uint64_t x)
1038 {
1039 unsigned int r = 64;
1040
1041 if (!x)
1042 return 0;
1043
1044 if (!(x & 0xFFFFFFFF00000000ULL)) {
1045 x <<= 32;
1046 r -= 32;
1047 }
1048 if (!(x & 0xFFFF000000000000ULL)) {
1049 x <<= 16;
1050 r -= 16;
1051 }
1052 if (!(x & 0xFF00000000000000ULL)) {
1053 x <<= 8;
1054 r -= 8;
1055 }
1056 if (!(x & 0xF000000000000000ULL)) {
1057 x <<= 4;
1058 r -= 4;
1059 }
1060 if (!(x & 0xC000000000000000ULL)) {
1061 x <<= 2;
1062 r -= 2;
1063 }
1064 if (!(x & 0x8000000000000000ULL)) {
1065 x <<= 1;
1066 r -= 1;
1067 }
1068 return r;
1069 }
1070 #endif
1071
1072 #ifndef HAS_FLS_U32
1073 static __attribute__((unused)) unsigned int fls_u32(uint32_t x)
1074 {
1075 unsigned int r = 32;
1076
1077 if (!x) {
1078 return 0;
1079 }
1080 if (!(x & 0xFFFF0000U)) {
1081 x <<= 16;
1082 r -= 16;
1083 }
1084 if (!(x & 0xFF000000U)) {
1085 x <<= 8;
1086 r -= 8;
1087 }
1088 if (!(x & 0xF0000000U)) {
1089 x <<= 4;
1090 r -= 4;
1091 }
1092 if (!(x & 0xC0000000U)) {
1093 x <<= 2;
1094 r -= 2;
1095 }
1096 if (!(x & 0x80000000U)) {
1097 x <<= 1;
1098 r -= 1;
1099 }
1100 return r;
1101 }
1102 #endif
1103
1104 /*
1105 * Return the minimum order for which x <= (1UL << order).
1106 * Return -1 if x is 0.
1107 */
1108 LTTNG_HIDDEN
1109 int utils_get_count_order_u32(uint32_t x)
1110 {
1111 if (!x) {
1112 return -1;
1113 }
1114
1115 return fls_u32(x - 1);
1116 }
1117
1118 /*
1119 * Return the minimum order for which x <= (1UL << order).
1120 * Return -1 if x is 0.
1121 */
1122 LTTNG_HIDDEN
1123 int utils_get_count_order_u64(uint64_t x)
1124 {
1125 if (!x) {
1126 return -1;
1127 }
1128
1129 return fls_u64(x - 1);
1130 }
1131
1132 /**
1133 * Obtain the value of LTTNG_HOME environment variable, if exists.
1134 * Otherwise returns the value of HOME.
1135 */
1136 LTTNG_HIDDEN
1137 const char *utils_get_home_dir(void)
1138 {
1139 char *val = NULL;
1140 struct passwd *pwd;
1141
1142 val = lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
1143 if (val != NULL) {
1144 goto end;
1145 }
1146 val = lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
1147 if (val != NULL) {
1148 goto end;
1149 }
1150
1151 /* Fallback on the password file entry. */
1152 pwd = getpwuid(getuid());
1153 if (!pwd) {
1154 goto end;
1155 }
1156 val = pwd->pw_dir;
1157
1158 DBG3("Home directory is '%s'", val);
1159
1160 end:
1161 return val;
1162 }
1163
1164 /**
1165 * Get user's home directory. Dynamically allocated, must be freed
1166 * by the caller.
1167 */
1168 LTTNG_HIDDEN
1169 char *utils_get_user_home_dir(uid_t uid)
1170 {
1171 struct passwd pwd;
1172 struct passwd *result;
1173 char *home_dir = NULL;
1174 char *buf = NULL;
1175 long buflen;
1176 int ret;
1177
1178 buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
1179 if (buflen == -1) {
1180 goto end;
1181 }
1182 retry:
1183 buf = zmalloc(buflen);
1184 if (!buf) {
1185 goto end;
1186 }
1187
1188 ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
1189 if (ret || !result) {
1190 if (ret == ERANGE) {
1191 free(buf);
1192 buflen *= 2;
1193 goto retry;
1194 }
1195 goto end;
1196 }
1197
1198 home_dir = strdup(pwd.pw_dir);
1199 end:
1200 free(buf);
1201 return home_dir;
1202 }
1203
1204 /*
1205 * With the given format, fill dst with the time of len maximum siz.
1206 *
1207 * Return amount of bytes set in the buffer or else 0 on error.
1208 */
1209 LTTNG_HIDDEN
1210 size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
1211 {
1212 size_t ret;
1213 time_t rawtime;
1214 struct tm *timeinfo;
1215
1216 assert(format);
1217 assert(dst);
1218
1219 /* Get date and time for session path */
1220 time(&rawtime);
1221 timeinfo = localtime(&rawtime);
1222 ret = strftime(dst, len, format, timeinfo);
1223 if (ret == 0) {
1224 ERR("Unable to strftime with format %s at dst %p of len %zu", format,
1225 dst, len);
1226 }
1227
1228 return ret;
1229 }
1230
1231 /*
1232 * Return 0 on success and set *gid to the group_ID matching the passed name.
1233 * Else -1 if it cannot be found or an error occurred.
1234 */
1235 LTTNG_HIDDEN
1236 int utils_get_group_id(const char *name, bool warn, gid_t *gid)
1237 {
1238 static volatile int warn_once;
1239 int ret;
1240 long sys_len;
1241 size_t len;
1242 struct group grp;
1243 struct group *result;
1244 struct lttng_dynamic_buffer buffer;
1245
1246 /* Get the system limit, if it exists. */
1247 sys_len = sysconf(_SC_GETGR_R_SIZE_MAX);
1248 if (sys_len == -1) {
1249 len = 1024;
1250 } else {
1251 len = (size_t) sys_len;
1252 }
1253
1254 lttng_dynamic_buffer_init(&buffer);
1255 ret = lttng_dynamic_buffer_set_size(&buffer, len);
1256 if (ret) {
1257 ERR("Failed to allocate group info buffer");
1258 ret = -1;
1259 goto error;
1260 }
1261
1262 while ((ret = getgrnam_r(name, &grp, buffer.data, buffer.size, &result)) == ERANGE) {
1263 const size_t new_len = 2 * buffer.size;
1264
1265 /* Buffer is not big enough, increase its size. */
1266 if (new_len < buffer.size) {
1267 ERR("Group info buffer size overflow");
1268 ret = -1;
1269 goto error;
1270 }
1271
1272 ret = lttng_dynamic_buffer_set_size(&buffer, new_len);
1273 if (ret) {
1274 ERR("Failed to grow group info buffer to %zu bytes",
1275 new_len);
1276 ret = -1;
1277 goto error;
1278 }
1279 }
1280 if (ret) {
1281 PERROR("Failed to get group file entry for group name \"%s\"",
1282 name);
1283 ret = -1;
1284 goto error;
1285 }
1286
1287 /* Group not found. */
1288 if (!result) {
1289 ret = -1;
1290 goto error;
1291 }
1292
1293 *gid = result->gr_gid;
1294 ret = 0;
1295
1296 error:
1297 if (ret && warn && !warn_once) {
1298 WARN("No tracing group detected");
1299 warn_once = 1;
1300 }
1301 lttng_dynamic_buffer_reset(&buffer);
1302 return ret;
1303 }
1304
1305 /*
1306 * Return a newly allocated option string. This string is to be used as the
1307 * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
1308 * of elements in the long_options array. Returns NULL if the string's
1309 * allocation fails.
1310 */
1311 LTTNG_HIDDEN
1312 char *utils_generate_optstring(const struct option *long_options,
1313 size_t opt_count)
1314 {
1315 int i;
1316 size_t string_len = opt_count, str_pos = 0;
1317 char *optstring;
1318
1319 /*
1320 * Compute the necessary string length. One letter per option, two when an
1321 * argument is necessary, and a trailing NULL.
1322 */
1323 for (i = 0; i < opt_count; i++) {
1324 string_len += long_options[i].has_arg ? 1 : 0;
1325 }
1326
1327 optstring = zmalloc(string_len);
1328 if (!optstring) {
1329 goto end;
1330 }
1331
1332 for (i = 0; i < opt_count; i++) {
1333 if (!long_options[i].name) {
1334 /* Got to the trailing NULL element */
1335 break;
1336 }
1337
1338 if (long_options[i].val != '\0') {
1339 optstring[str_pos++] = (char) long_options[i].val;
1340 if (long_options[i].has_arg) {
1341 optstring[str_pos++] = ':';
1342 }
1343 }
1344 }
1345
1346 end:
1347 return optstring;
1348 }
1349
1350 /*
1351 * Try to remove a hierarchy of empty directories, recursively. Don't unlink
1352 * any file. Try to rmdir any empty directory within the hierarchy.
1353 */
1354 LTTNG_HIDDEN
1355 int utils_recursive_rmdir(const char *path)
1356 {
1357 int ret;
1358 struct lttng_directory_handle *handle;
1359
1360 handle = lttng_directory_handle_create(NULL);
1361 if (!handle) {
1362 ret = -1;
1363 goto end;
1364 }
1365 ret = lttng_directory_handle_remove_subdirectory(handle, path);
1366 end:
1367 lttng_directory_handle_put(handle);
1368 return ret;
1369 }
1370
1371 LTTNG_HIDDEN
1372 int utils_truncate_stream_file(int fd, off_t length)
1373 {
1374 int ret;
1375 off_t lseek_ret;
1376
1377 ret = ftruncate(fd, length);
1378 if (ret < 0) {
1379 PERROR("ftruncate");
1380 goto end;
1381 }
1382 lseek_ret = lseek(fd, length, SEEK_SET);
1383 if (lseek_ret < 0) {
1384 PERROR("lseek");
1385 ret = -1;
1386 goto end;
1387 }
1388 end:
1389 return ret;
1390 }
1391
1392 static const char *get_man_bin_path(void)
1393 {
1394 char *env_man_path = lttng_secure_getenv(DEFAULT_MAN_BIN_PATH_ENV);
1395
1396 if (env_man_path) {
1397 return env_man_path;
1398 }
1399
1400 return DEFAULT_MAN_BIN_PATH;
1401 }
1402
1403 LTTNG_HIDDEN
1404 int utils_show_help(int section, const char *page_name,
1405 const char *help_msg)
1406 {
1407 char section_string[8];
1408 const char *man_bin_path = get_man_bin_path();
1409 int ret = 0;
1410
1411 if (help_msg) {
1412 printf("%s", help_msg);
1413 goto end;
1414 }
1415
1416 /* Section integer -> section string */
1417 ret = sprintf(section_string, "%d", section);
1418 assert(ret > 0 && ret < 8);
1419
1420 /*
1421 * Execute man pager.
1422 *
1423 * We provide -M to man here because LTTng-tools can
1424 * be installed outside /usr, in which case its man pages are
1425 * not located in the default /usr/share/man directory.
1426 */
1427 ret = execlp(man_bin_path, "man", "-M", MANPATH,
1428 section_string, page_name, NULL);
1429
1430 end:
1431 return ret;
1432 }
1433
1434 static
1435 int read_proc_meminfo_field(const char *field, size_t *value)
1436 {
1437 int ret;
1438 FILE *proc_meminfo;
1439 char name[PROC_MEMINFO_FIELD_MAX_NAME_LEN] = {};
1440
1441 proc_meminfo = fopen(PROC_MEMINFO_PATH, "r");
1442 if (!proc_meminfo) {
1443 PERROR("Failed to fopen() " PROC_MEMINFO_PATH);
1444 ret = -1;
1445 goto fopen_error;
1446 }
1447
1448 /*
1449 * Read the contents of /proc/meminfo line by line to find the right
1450 * field.
1451 */
1452 while (!feof(proc_meminfo)) {
1453 unsigned long value_kb;
1454
1455 ret = fscanf(proc_meminfo,
1456 "%" MAX_NAME_LEN_SCANF_IS_A_BROKEN_API "s %lu kB\n",
1457 name, &value_kb);
1458 if (ret == EOF) {
1459 /*
1460 * fscanf() returning EOF can indicate EOF or an error.
1461 */
1462 if (ferror(proc_meminfo)) {
1463 PERROR("Failed to parse " PROC_MEMINFO_PATH);
1464 }
1465 break;
1466 }
1467
1468 if (ret == 2 && strcmp(name, field) == 0) {
1469 /*
1470 * This number is displayed in kilo-bytes. Return the
1471 * number of bytes.
1472 */
1473 *value = ((size_t) value_kb) * 1024;
1474 ret = 0;
1475 goto found;
1476 }
1477 }
1478 /* Reached the end of the file without finding the right field. */
1479 ret = -1;
1480
1481 found:
1482 fclose(proc_meminfo);
1483 fopen_error:
1484 return ret;
1485 }
1486
1487 /*
1488 * Returns an estimate of the number of bytes of memory available based on the
1489 * the information in `/proc/meminfo`. The number returned by this function is
1490 * a best guess.
1491 */
1492 LTTNG_HIDDEN
1493 int utils_get_memory_available(size_t *value)
1494 {
1495 return read_proc_meminfo_field(PROC_MEMINFO_MEMAVAILABLE_LINE, value);
1496 }
1497
1498 /*
1499 * Returns the total size of the memory on the system in bytes based on the
1500 * the information in `/proc/meminfo`.
1501 */
1502 LTTNG_HIDDEN
1503 int utils_get_memory_total(size_t *value)
1504 {
1505 return read_proc_meminfo_field(PROC_MEMINFO_MEMTOTAL_LINE, value);
1506 }
1507
1508 LTTNG_HIDDEN
1509 int utils_change_working_directory(const char *path)
1510 {
1511 int ret;
1512
1513 assert(path);
1514
1515 DBG("Changing working directory to \"%s\"", path);
1516 ret = chdir(path);
1517 if (ret) {
1518 PERROR("Failed to change working directory to \"%s\"", path);
1519 goto end;
1520 }
1521
1522 /* Check for write access */
1523 if (access(path, W_OK)) {
1524 if (errno == EACCES) {
1525 /*
1526 * Do not treat this as an error since the permission
1527 * might change in the lifetime of the process
1528 */
1529 DBG("Working directory \"%s\" is not writable", path);
1530 } else {
1531 PERROR("Failed to check if working directory \"%s\" is writable",
1532 path);
1533 }
1534 }
1535
1536 end:
1537 return ret;
1538 }
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