2e07d4ff0b6d366268755b7969dab0d58199385e
[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 ret = lttng_directory_handle_init(&handle, NULL);
692 if (ret) {
693 goto end;
694 }
695 ret = lttng_directory_handle_create_subdirectory_as_user(
696 &handle, path, mode,
697 (uid >= 0 || gid >= 0) ? &creds : NULL);
698 lttng_directory_handle_fini(&handle);
699 end:
700 return ret;
701 }
702
703 /*
704 * Recursively create directory using the given path and mode, under the
705 * provided uid and gid.
706 *
707 * On success, return 0 else a negative error code.
708 */
709 LTTNG_HIDDEN
710 int utils_mkdir_recursive(const char *path, mode_t mode, int uid, int gid)
711 {
712 int ret;
713 struct lttng_directory_handle handle;
714 const struct lttng_credentials creds = {
715 .uid = (uid_t) uid,
716 .gid = (gid_t) gid,
717 };
718
719 ret = lttng_directory_handle_init(&handle, NULL);
720 if (ret) {
721 goto end;
722 }
723 ret = lttng_directory_handle_create_subdirectory_recursive_as_user(
724 &handle, path, mode,
725 (uid >= 0 || gid >= 0) ? &creds : NULL);
726 lttng_directory_handle_fini(&handle);
727 end:
728 return ret;
729 }
730
731 /*
732 * out_stream_path is the output parameter.
733 *
734 * Return 0 on success or else a negative value.
735 */
736 LTTNG_HIDDEN
737 int utils_stream_file_path(const char *path_name, const char *file_name,
738 uint64_t size, uint64_t count, const char *suffix,
739 char *out_stream_path, size_t stream_path_len)
740 {
741 int ret;
742 char count_str[MAX_INT_DEC_LEN(count) + 1] = {};
743 const char *path_separator;
744
745 if (path_name && path_name[strlen(path_name) - 1] == '/') {
746 path_separator = "";
747 } else {
748 path_separator = "/";
749 }
750
751 path_name = path_name ? : "";
752 suffix = suffix ? : "";
753 if (size > 0) {
754 ret = snprintf(count_str, sizeof(count_str), "_%" PRIu64,
755 count);
756 assert(ret > 0 && ret < sizeof(count_str));
757 }
758
759 ret = snprintf(out_stream_path, stream_path_len, "%s%s%s%s%s",
760 path_name, path_separator, file_name, count_str,
761 suffix);
762 if (ret < 0 || ret >= stream_path_len) {
763 ERR("Truncation occurred while formatting stream path");
764 ret = -1;
765 } else {
766 ret = 0;
767 }
768 return ret;
769 }
770
771 /**
772 * Parse a string that represents a size in human readable format. It
773 * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
774 *
775 * The suffix multiply the integer by:
776 * 'k': 1024
777 * 'M': 1024^2
778 * 'G': 1024^3
779 *
780 * @param str The string to parse.
781 * @param size Pointer to a uint64_t that will be filled with the
782 * resulting size.
783 *
784 * @return 0 on success, -1 on failure.
785 */
786 LTTNG_HIDDEN
787 int utils_parse_size_suffix(const char * const str, uint64_t * const size)
788 {
789 int ret;
790 uint64_t base_size;
791 long shift = 0;
792 const char *str_end;
793 char *num_end;
794
795 if (!str) {
796 DBG("utils_parse_size_suffix: received a NULL string.");
797 ret = -1;
798 goto end;
799 }
800
801 /* strtoull will accept a negative number, but we don't want to. */
802 if (strchr(str, '-') != NULL) {
803 DBG("utils_parse_size_suffix: invalid size string, should not contain '-'.");
804 ret = -1;
805 goto end;
806 }
807
808 /* str_end will point to the \0 */
809 str_end = str + strlen(str);
810 errno = 0;
811 base_size = strtoull(str, &num_end, 0);
812 if (errno != 0) {
813 PERROR("utils_parse_size_suffix strtoull");
814 ret = -1;
815 goto end;
816 }
817
818 if (num_end == str) {
819 /* strtoull parsed nothing, not good. */
820 DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
821 ret = -1;
822 goto end;
823 }
824
825 /* Check if a prefix is present. */
826 switch (*num_end) {
827 case 'G':
828 shift = GIBI_LOG2;
829 num_end++;
830 break;
831 case 'M': /* */
832 shift = MEBI_LOG2;
833 num_end++;
834 break;
835 case 'K':
836 case 'k':
837 shift = KIBI_LOG2;
838 num_end++;
839 break;
840 case '\0':
841 break;
842 default:
843 DBG("utils_parse_size_suffix: invalid suffix.");
844 ret = -1;
845 goto end;
846 }
847
848 /* Check for garbage after the valid input. */
849 if (num_end != str_end) {
850 DBG("utils_parse_size_suffix: Garbage after size string.");
851 ret = -1;
852 goto end;
853 }
854
855 *size = base_size << shift;
856
857 /* Check for overflow */
858 if ((*size >> shift) != base_size) {
859 DBG("utils_parse_size_suffix: oops, overflow detected.");
860 ret = -1;
861 goto end;
862 }
863
864 ret = 0;
865 end:
866 return ret;
867 }
868
869 /**
870 * Parse a string that represents a time in human readable format. It
871 * supports decimal integers suffixed by:
872 * "us" for microsecond,
873 * "ms" for millisecond,
874 * "s" for second,
875 * "m" for minute,
876 * "h" for hour
877 *
878 * The suffix multiply the integer by:
879 * "us" : 1
880 * "ms" : 1000
881 * "s" : 1000000
882 * "m" : 60000000
883 * "h" : 3600000000
884 *
885 * Note that unit-less numbers are assumed to be microseconds.
886 *
887 * @param str The string to parse, assumed to be NULL-terminated.
888 * @param time_us Pointer to a uint64_t that will be filled with the
889 * resulting time in microseconds.
890 *
891 * @return 0 on success, -1 on failure.
892 */
893 LTTNG_HIDDEN
894 int utils_parse_time_suffix(char const * const str, uint64_t * const time_us)
895 {
896 int ret;
897 uint64_t base_time;
898 uint64_t multiplier = 1;
899 const char *str_end;
900 char *num_end;
901
902 if (!str) {
903 DBG("utils_parse_time_suffix: received a NULL string.");
904 ret = -1;
905 goto end;
906 }
907
908 /* strtoull will accept a negative number, but we don't want to. */
909 if (strchr(str, '-') != NULL) {
910 DBG("utils_parse_time_suffix: invalid time string, should not contain '-'.");
911 ret = -1;
912 goto end;
913 }
914
915 /* str_end will point to the \0 */
916 str_end = str + strlen(str);
917 errno = 0;
918 base_time = strtoull(str, &num_end, 10);
919 if (errno != 0) {
920 PERROR("utils_parse_time_suffix strtoull on string \"%s\"", str);
921 ret = -1;
922 goto end;
923 }
924
925 if (num_end == str) {
926 /* strtoull parsed nothing, not good. */
927 DBG("utils_parse_time_suffix: strtoull had nothing good to parse.");
928 ret = -1;
929 goto end;
930 }
931
932 /* Check if a prefix is present. */
933 switch (*num_end) {
934 case 'u':
935 /*
936 * Microsecond (us)
937 *
938 * Skip the "us" if the string matches the "us" suffix,
939 * otherwise let the check for the end of the string handle
940 * the error reporting.
941 */
942 if (*(num_end + 1) == 's') {
943 num_end += 2;
944 }
945 break;
946 case 'm':
947 if (*(num_end + 1) == 's') {
948 /* Millisecond (ms) */
949 multiplier = USEC_PER_MSEC;
950 /* Skip the 's' */
951 num_end++;
952 } else {
953 /* Minute (m) */
954 multiplier = USEC_PER_MINUTE;
955 }
956 num_end++;
957 break;
958 case 's':
959 /* Second */
960 multiplier = USEC_PER_SEC;
961 num_end++;
962 break;
963 case 'h':
964 /* Hour */
965 multiplier = USEC_PER_HOURS;
966 num_end++;
967 break;
968 case '\0':
969 break;
970 default:
971 DBG("utils_parse_time_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_time_suffix: Garbage after time string.");
979 ret = -1;
980 goto end;
981 }
982
983 *time_us = base_time * multiplier;
984
985 /* Check for overflow */
986 if ((*time_us / multiplier) != base_time) {
987 DBG("utils_parse_time_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 #if defined(__x86_64) && defined(__LP64__)
1018 static inline
1019 unsigned int fls_u64(uint64_t x)
1020 {
1021 long r;
1022
1023 asm("bsrq %1,%0\n\t"
1024 "jnz 1f\n\t"
1025 "movq $-1,%0\n\t"
1026 "1:\n\t"
1027 : "=r" (r) : "rm" (x));
1028 return r + 1;
1029 }
1030 #define HAS_FLS_U64
1031 #endif
1032
1033 #ifndef HAS_FLS_U64
1034 static __attribute__((unused))
1035 unsigned int fls_u64(uint64_t x)
1036 {
1037 unsigned int r = 64;
1038
1039 if (!x)
1040 return 0;
1041
1042 if (!(x & 0xFFFFFFFF00000000ULL)) {
1043 x <<= 32;
1044 r -= 32;
1045 }
1046 if (!(x & 0xFFFF000000000000ULL)) {
1047 x <<= 16;
1048 r -= 16;
1049 }
1050 if (!(x & 0xFF00000000000000ULL)) {
1051 x <<= 8;
1052 r -= 8;
1053 }
1054 if (!(x & 0xF000000000000000ULL)) {
1055 x <<= 4;
1056 r -= 4;
1057 }
1058 if (!(x & 0xC000000000000000ULL)) {
1059 x <<= 2;
1060 r -= 2;
1061 }
1062 if (!(x & 0x8000000000000000ULL)) {
1063 x <<= 1;
1064 r -= 1;
1065 }
1066 return r;
1067 }
1068 #endif
1069
1070 #ifndef HAS_FLS_U32
1071 static __attribute__((unused)) unsigned int fls_u32(uint32_t x)
1072 {
1073 unsigned int r = 32;
1074
1075 if (!x) {
1076 return 0;
1077 }
1078 if (!(x & 0xFFFF0000U)) {
1079 x <<= 16;
1080 r -= 16;
1081 }
1082 if (!(x & 0xFF000000U)) {
1083 x <<= 8;
1084 r -= 8;
1085 }
1086 if (!(x & 0xF0000000U)) {
1087 x <<= 4;
1088 r -= 4;
1089 }
1090 if (!(x & 0xC0000000U)) {
1091 x <<= 2;
1092 r -= 2;
1093 }
1094 if (!(x & 0x80000000U)) {
1095 x <<= 1;
1096 r -= 1;
1097 }
1098 return r;
1099 }
1100 #endif
1101
1102 /*
1103 * Return the minimum order for which x <= (1UL << order).
1104 * Return -1 if x is 0.
1105 */
1106 LTTNG_HIDDEN
1107 int utils_get_count_order_u32(uint32_t x)
1108 {
1109 if (!x) {
1110 return -1;
1111 }
1112
1113 return fls_u32(x - 1);
1114 }
1115
1116 /*
1117 * Return the minimum order for which x <= (1UL << order).
1118 * Return -1 if x is 0.
1119 */
1120 LTTNG_HIDDEN
1121 int utils_get_count_order_u64(uint64_t x)
1122 {
1123 if (!x) {
1124 return -1;
1125 }
1126
1127 return fls_u64(x - 1);
1128 }
1129
1130 /**
1131 * Obtain the value of LTTNG_HOME environment variable, if exists.
1132 * Otherwise returns the value of HOME.
1133 */
1134 LTTNG_HIDDEN
1135 const char *utils_get_home_dir(void)
1136 {
1137 char *val = NULL;
1138 struct passwd *pwd;
1139
1140 val = lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
1141 if (val != NULL) {
1142 goto end;
1143 }
1144 val = lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
1145 if (val != NULL) {
1146 goto end;
1147 }
1148
1149 /* Fallback on the password file entry. */
1150 pwd = getpwuid(getuid());
1151 if (!pwd) {
1152 goto end;
1153 }
1154 val = pwd->pw_dir;
1155
1156 DBG3("Home directory is '%s'", val);
1157
1158 end:
1159 return val;
1160 }
1161
1162 /**
1163 * Get user's home directory. Dynamically allocated, must be freed
1164 * by the caller.
1165 */
1166 LTTNG_HIDDEN
1167 char *utils_get_user_home_dir(uid_t uid)
1168 {
1169 struct passwd pwd;
1170 struct passwd *result;
1171 char *home_dir = NULL;
1172 char *buf = NULL;
1173 long buflen;
1174 int ret;
1175
1176 buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
1177 if (buflen == -1) {
1178 goto end;
1179 }
1180 retry:
1181 buf = zmalloc(buflen);
1182 if (!buf) {
1183 goto end;
1184 }
1185
1186 ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
1187 if (ret || !result) {
1188 if (ret == ERANGE) {
1189 free(buf);
1190 buflen *= 2;
1191 goto retry;
1192 }
1193 goto end;
1194 }
1195
1196 home_dir = strdup(pwd.pw_dir);
1197 end:
1198 free(buf);
1199 return home_dir;
1200 }
1201
1202 /*
1203 * With the given format, fill dst with the time of len maximum siz.
1204 *
1205 * Return amount of bytes set in the buffer or else 0 on error.
1206 */
1207 LTTNG_HIDDEN
1208 size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
1209 {
1210 size_t ret;
1211 time_t rawtime;
1212 struct tm *timeinfo;
1213
1214 assert(format);
1215 assert(dst);
1216
1217 /* Get date and time for session path */
1218 time(&rawtime);
1219 timeinfo = localtime(&rawtime);
1220 ret = strftime(dst, len, format, timeinfo);
1221 if (ret == 0) {
1222 ERR("Unable to strftime with format %s at dst %p of len %zu", format,
1223 dst, len);
1224 }
1225
1226 return ret;
1227 }
1228
1229 /*
1230 * Return 0 on success and set *gid to the group_ID matching the passed name.
1231 * Else -1 if it cannot be found or an error occurred.
1232 */
1233 LTTNG_HIDDEN
1234 int utils_get_group_id(const char *name, bool warn, gid_t *gid)
1235 {
1236 static volatile int warn_once;
1237 int ret;
1238 long sys_len;
1239 size_t len;
1240 struct group grp;
1241 struct group *result;
1242 struct lttng_dynamic_buffer buffer;
1243
1244 /* Get the system limit, if it exists. */
1245 sys_len = sysconf(_SC_GETGR_R_SIZE_MAX);
1246 if (sys_len == -1) {
1247 len = 1024;
1248 } else {
1249 len = (size_t) sys_len;
1250 }
1251
1252 lttng_dynamic_buffer_init(&buffer);
1253 ret = lttng_dynamic_buffer_set_size(&buffer, len);
1254 if (ret) {
1255 ERR("Failed to allocate group info buffer");
1256 ret = -1;
1257 goto error;
1258 }
1259
1260 while ((ret = getgrnam_r(name, &grp, buffer.data, buffer.size, &result)) == ERANGE) {
1261 const size_t new_len = 2 * buffer.size;
1262
1263 /* Buffer is not big enough, increase its size. */
1264 if (new_len < buffer.size) {
1265 ERR("Group info buffer size overflow");
1266 ret = -1;
1267 goto error;
1268 }
1269
1270 ret = lttng_dynamic_buffer_set_size(&buffer, new_len);
1271 if (ret) {
1272 ERR("Failed to grow group info buffer to %zu bytes",
1273 new_len);
1274 ret = -1;
1275 goto error;
1276 }
1277 }
1278 if (ret) {
1279 PERROR("Failed to get group file entry for group name \"%s\"",
1280 name);
1281 ret = -1;
1282 goto error;
1283 }
1284
1285 /* Group not found. */
1286 if (!result) {
1287 ret = -1;
1288 goto error;
1289 }
1290
1291 *gid = result->gr_gid;
1292 ret = 0;
1293
1294 error:
1295 if (ret && warn && !warn_once) {
1296 WARN("No tracing group detected");
1297 warn_once = 1;
1298 }
1299 lttng_dynamic_buffer_reset(&buffer);
1300 return ret;
1301 }
1302
1303 /*
1304 * Return a newly allocated option string. This string is to be used as the
1305 * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
1306 * of elements in the long_options array. Returns NULL if the string's
1307 * allocation fails.
1308 */
1309 LTTNG_HIDDEN
1310 char *utils_generate_optstring(const struct option *long_options,
1311 size_t opt_count)
1312 {
1313 int i;
1314 size_t string_len = opt_count, str_pos = 0;
1315 char *optstring;
1316
1317 /*
1318 * Compute the necessary string length. One letter per option, two when an
1319 * argument is necessary, and a trailing NULL.
1320 */
1321 for (i = 0; i < opt_count; i++) {
1322 string_len += long_options[i].has_arg ? 1 : 0;
1323 }
1324
1325 optstring = zmalloc(string_len);
1326 if (!optstring) {
1327 goto end;
1328 }
1329
1330 for (i = 0; i < opt_count; i++) {
1331 if (!long_options[i].name) {
1332 /* Got to the trailing NULL element */
1333 break;
1334 }
1335
1336 if (long_options[i].val != '\0') {
1337 optstring[str_pos++] = (char) long_options[i].val;
1338 if (long_options[i].has_arg) {
1339 optstring[str_pos++] = ':';
1340 }
1341 }
1342 }
1343
1344 end:
1345 return optstring;
1346 }
1347
1348 /*
1349 * Try to remove a hierarchy of empty directories, recursively. Don't unlink
1350 * any file. Try to rmdir any empty directory within the hierarchy.
1351 */
1352 LTTNG_HIDDEN
1353 int utils_recursive_rmdir(const char *path)
1354 {
1355 int ret;
1356 struct lttng_directory_handle handle;
1357
1358 ret = lttng_directory_handle_init(&handle, NULL);
1359 if (ret) {
1360 goto end;
1361 }
1362 ret = lttng_directory_handle_remove_subdirectory(&handle, path);
1363 lttng_directory_handle_fini(&handle);
1364 end:
1365 return ret;
1366 }
1367
1368 LTTNG_HIDDEN
1369 int utils_truncate_stream_file(int fd, off_t length)
1370 {
1371 int ret;
1372 off_t lseek_ret;
1373
1374 ret = ftruncate(fd, length);
1375 if (ret < 0) {
1376 PERROR("ftruncate");
1377 goto end;
1378 }
1379 lseek_ret = lseek(fd, length, SEEK_SET);
1380 if (lseek_ret < 0) {
1381 PERROR("lseek");
1382 ret = -1;
1383 goto end;
1384 }
1385 end:
1386 return ret;
1387 }
1388
1389 static const char *get_man_bin_path(void)
1390 {
1391 char *env_man_path = lttng_secure_getenv(DEFAULT_MAN_BIN_PATH_ENV);
1392
1393 if (env_man_path) {
1394 return env_man_path;
1395 }
1396
1397 return DEFAULT_MAN_BIN_PATH;
1398 }
1399
1400 LTTNG_HIDDEN
1401 int utils_show_help(int section, const char *page_name,
1402 const char *help_msg)
1403 {
1404 char section_string[8];
1405 const char *man_bin_path = get_man_bin_path();
1406 int ret = 0;
1407
1408 if (help_msg) {
1409 printf("%s", help_msg);
1410 goto end;
1411 }
1412
1413 /* Section integer -> section string */
1414 ret = sprintf(section_string, "%d", section);
1415 assert(ret > 0 && ret < 8);
1416
1417 /*
1418 * Execute man pager.
1419 *
1420 * We provide -M to man here because LTTng-tools can
1421 * be installed outside /usr, in which case its man pages are
1422 * not located in the default /usr/share/man directory.
1423 */
1424 ret = execlp(man_bin_path, "man", "-M", MANPATH,
1425 section_string, page_name, NULL);
1426
1427 end:
1428 return ret;
1429 }
1430
1431 static
1432 int read_proc_meminfo_field(const char *field, size_t *value)
1433 {
1434 int ret;
1435 FILE *proc_meminfo;
1436 char name[PROC_MEMINFO_FIELD_MAX_NAME_LEN] = {};
1437
1438 proc_meminfo = fopen(PROC_MEMINFO_PATH, "r");
1439 if (!proc_meminfo) {
1440 PERROR("Failed to fopen() " PROC_MEMINFO_PATH);
1441 ret = -1;
1442 goto fopen_error;
1443 }
1444
1445 /*
1446 * Read the contents of /proc/meminfo line by line to find the right
1447 * field.
1448 */
1449 while (!feof(proc_meminfo)) {
1450 unsigned long value_kb;
1451
1452 ret = fscanf(proc_meminfo,
1453 "%" MAX_NAME_LEN_SCANF_IS_A_BROKEN_API "s %lu kB\n",
1454 name, &value_kb);
1455 if (ret == EOF) {
1456 /*
1457 * fscanf() returning EOF can indicate EOF or an error.
1458 */
1459 if (ferror(proc_meminfo)) {
1460 PERROR("Failed to parse " PROC_MEMINFO_PATH);
1461 }
1462 break;
1463 }
1464
1465 if (ret == 2 && strcmp(name, field) == 0) {
1466 /*
1467 * This number is displayed in kilo-bytes. Return the
1468 * number of bytes.
1469 */
1470 *value = ((size_t) value_kb) * 1024;
1471 ret = 0;
1472 goto found;
1473 }
1474 }
1475 /* Reached the end of the file without finding the right field. */
1476 ret = -1;
1477
1478 found:
1479 fclose(proc_meminfo);
1480 fopen_error:
1481 return ret;
1482 }
1483
1484 /*
1485 * Returns an estimate of the number of bytes of memory available based on the
1486 * the information in `/proc/meminfo`. The number returned by this function is
1487 * a best guess.
1488 */
1489 LTTNG_HIDDEN
1490 int utils_get_memory_available(size_t *value)
1491 {
1492 return read_proc_meminfo_field(PROC_MEMINFO_MEMAVAILABLE_LINE, value);
1493 }
1494
1495 /*
1496 * Returns the total size of the memory on the system in bytes based on the
1497 * the information in `/proc/meminfo`.
1498 */
1499 LTTNG_HIDDEN
1500 int utils_get_memory_total(size_t *value)
1501 {
1502 return read_proc_meminfo_field(PROC_MEMINFO_MEMTOTAL_LINE, value);
1503 }
1504
1505 LTTNG_HIDDEN
1506 int utils_change_working_directory(const char *path)
1507 {
1508 int ret;
1509
1510 assert(path);
1511
1512 DBG("Changing working directory to \"%s\"", path);
1513 ret = chdir(path);
1514 if (ret) {
1515 PERROR("Failed to change working directory to \"%s\"", path);
1516 goto end;
1517 }
1518
1519 /* Check for write access */
1520 if (access(path, W_OK)) {
1521 if (errno == EACCES) {
1522 /*
1523 * Do not treat this as an error since the permission
1524 * might change in the lifetime of the process
1525 */
1526 DBG("Working directory \"%s\" is not writable", path);
1527 } else {
1528 PERROR("Failed to check if working directory \"%s\" is writable",
1529 path);
1530 }
1531 }
1532
1533 end:
1534 return ret;
1535 }
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