Implement --shm-path option for UST sessions (per-uid channels)
[lttng-tools.git] / src / common / utils.c
CommitLineData
81b86775
DG
1/*
2 * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
66495845 3 * Copyright (C) 2013 - Raphaël Beamonte <raphael.beamonte@gmail.com>
8db0dc00 4 * Copyright (C) 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
81b86775
DG
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License, version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20#define _GNU_SOURCE
6c1c0768 21#define _LGPL_SOURCE
35f90c40 22#include <assert.h>
81b86775
DG
23#include <ctype.h>
24#include <fcntl.h>
25#include <limits.h>
26#include <stdlib.h>
27#include <string.h>
2d851108 28#include <sys/stat.h>
0c7bcad5 29#include <sys/types.h>
2d851108 30#include <unistd.h>
fe4477ee 31#include <inttypes.h>
6c71277b 32#include <grp.h>
fb198a11 33#include <pwd.h>
c9cb3e7d 34#include <sys/file.h>
81b86775
DG
35
36#include <common/common.h>
fe4477ee 37#include <common/runas.h>
e8fa9fb0 38#include <common/compat/getenv.h>
81b86775
DG
39
40#include "utils.h"
feb0f3e5 41#include "defaults.h"
81b86775 42
5154230f
RB
43/*
44 * Return a partial realpath(3) of the path even if the full path does not
45 * exist. For instance, with /tmp/test1/test2/test3, if test2/ does not exist
46 * but the /tmp/test1 does, the real path for /tmp/test1 is concatened with
47 * /test2/test3 then returned. In normal time, realpath(3) fails if the end
48 * point directory does not exist.
49 * In case resolved_path is NULL, the string returned was allocated in the
50 * function and thus need to be freed by the caller. The size argument allows
51 * to specify the size of the resolved_path argument if given, or the size to
52 * allocate.
53 */
54LTTNG_HIDDEN
55char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
56{
57 char *cut_path, *try_path = NULL, *try_path_prev = NULL;
58 const char *next, *prev, *end;
59
60 /* Safety net */
61 if (path == NULL) {
62 goto error;
63 }
64
65 /*
66 * Identify the end of the path, we don't want to treat the
67 * last char if it is a '/', we will just keep it on the side
68 * to be added at the end, and return a value coherent with
69 * the path given as argument
70 */
71 end = path + strlen(path);
72 if (*(end-1) == '/') {
73 end--;
74 }
75
76 /* Initiate the values of the pointers before looping */
77 next = path;
78 prev = next;
79 /* Only to ensure try_path is not NULL to enter the while */
80 try_path = (char *)next;
81
82 /* Resolve the canonical path of the first part of the path */
83 while (try_path != NULL && next != end) {
84 /*
85 * If there is not any '/' left, we want to try with
86 * the full path
87 */
88 next = strpbrk(next + 1, "/");
89 if (next == NULL) {
90 next = end;
91 }
92
93 /* Cut the part we will be trying to resolve */
94 cut_path = strndup(path, next - path);
d9dbcf5e
MD
95 if (cut_path == NULL) {
96 PERROR("strndup");
97 goto error;
98 }
5154230f
RB
99
100 /* Try to resolve this part */
101 try_path = realpath((char *)cut_path, NULL);
102 if (try_path == NULL) {
103 /*
104 * There was an error, we just want to be assured it
105 * is linked to an unexistent directory, if it's another
106 * reason, we spawn an error
107 */
108 switch (errno) {
109 case ENOENT:
110 /* Ignore the error */
111 break;
112 default:
113 PERROR("realpath (partial_realpath)");
114 goto error;
115 break;
116 }
117 } else {
118 /* Save the place we are before trying the next step */
119 free(try_path_prev);
120 try_path_prev = try_path;
121 prev = next;
122 }
123
124 /* Free the allocated memory */
125 free(cut_path);
126 };
127
128 /* Allocate memory for the resolved path if necessary */
129 if (resolved_path == NULL) {
130 resolved_path = zmalloc(size);
131 if (resolved_path == NULL) {
132 PERROR("zmalloc resolved path");
133 goto error;
134 }
135 }
136
137 /*
138 * If we were able to solve at least partially the path, we can concatenate
139 * what worked and what didn't work
140 */
141 if (try_path_prev != NULL) {
142 /* If we risk to concatenate two '/', we remove one of them */
143 if (try_path_prev[strlen(try_path_prev) - 1] == '/' && prev[0] == '/') {
144 try_path_prev[strlen(try_path_prev) - 1] = '\0';
145 }
146
147 /*
148 * Duplicate the memory used by prev in case resolved_path and
149 * path are pointers for the same memory space
150 */
151 cut_path = strdup(prev);
d9dbcf5e
MD
152 if (cut_path == NULL) {
153 PERROR("strdup");
154 goto error;
155 }
5154230f
RB
156
157 /* Concatenate the strings */
158 snprintf(resolved_path, size, "%s%s", try_path_prev, cut_path);
159
160 /* Free the allocated memory */
161 free(cut_path);
162 free(try_path_prev);
163 /*
164 * Else, we just copy the path in our resolved_path to
165 * return it as is
166 */
167 } else {
168 strncpy(resolved_path, path, size);
169 }
170
171 /* Then we return the 'partially' resolved path */
172 return resolved_path;
173
174error:
175 free(resolved_path);
176 return NULL;
177}
178
81b86775 179/*
3d229795
RB
180 * Make a full resolution of the given path even if it doesn't exist.
181 * This function uses the utils_partial_realpath function to resolve
182 * symlinks and relatives paths at the start of the string, and
183 * implements functionnalities to resolve the './' and '../' strings
184 * in the middle of a path. This function is only necessary because
185 * realpath(3) does not accept to resolve unexistent paths.
186 * The returned string was allocated in the function, it is thus of
187 * the responsibility of the caller to free this memory.
81b86775 188 */
90e535ef 189LTTNG_HIDDEN
81b86775
DG
190char *utils_expand_path(const char *path)
191{
3d229795 192 char *next, *previous, *slash, *start_path, *absolute_path = NULL;
5de083f4
RB
193 char *last_token;
194 int is_dot, is_dotdot;
81b86775
DG
195
196 /* Safety net */
197 if (path == NULL) {
198 goto error;
199 }
200
3d229795
RB
201 /* Allocate memory for the absolute_path */
202 absolute_path = zmalloc(PATH_MAX);
203 if (absolute_path == NULL) {
81b86775
DG
204 PERROR("zmalloc expand path");
205 goto error;
206 }
207
3d229795
RB
208 /*
209 * If the path is not already absolute nor explicitly relative,
210 * consider we're in the current directory
211 */
212 if (*path != '/' && strncmp(path, "./", 2) != 0 &&
213 strncmp(path, "../", 3) != 0) {
214 snprintf(absolute_path, PATH_MAX, "./%s", path);
2dcd84b7 215 /* Else, we just copy the path */
116f95d9 216 } else {
3d229795
RB
217 strncpy(absolute_path, path, PATH_MAX);
218 }
116f95d9 219
3d229795
RB
220 /* Resolve partially our path */
221 absolute_path = utils_partial_realpath(absolute_path,
222 absolute_path, PATH_MAX);
116f95d9 223
3d229795
RB
224 /* As long as we find '/./' in the working_path string */
225 while ((next = strstr(absolute_path, "/./"))) {
116f95d9 226
3d229795
RB
227 /* We prepare the start_path not containing it */
228 start_path = strndup(absolute_path, next - absolute_path);
d9dbcf5e
MD
229 if (!start_path) {
230 PERROR("strndup");
231 goto error;
232 }
3d229795
RB
233 /* And we concatenate it with the part after this string */
234 snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 2);
116f95d9 235
3d229795
RB
236 free(start_path);
237 }
116f95d9 238
3d229795
RB
239 /* As long as we find '/../' in the working_path string */
240 while ((next = strstr(absolute_path, "/../"))) {
241 /* We find the last level of directory */
242 previous = absolute_path;
243 while ((slash = strpbrk(previous, "/")) && slash != next) {
244 previous = slash + 1;
81b86775 245 }
81b86775 246
3d229795
RB
247 /* Then we prepare the start_path not containing it */
248 start_path = strndup(absolute_path, previous - absolute_path);
d9dbcf5e
MD
249 if (!start_path) {
250 PERROR("strndup");
251 goto error;
252 }
3d229795
RB
253
254 /* And we concatenate it with the part after the '/../' */
255 snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 4);
256
257 /* We can free the memory used for the start path*/
258 free(start_path);
259
260 /* Then we verify for symlinks using partial_realpath */
261 absolute_path = utils_partial_realpath(absolute_path,
262 absolute_path, PATH_MAX);
116f95d9 263 }
81b86775 264
5de083f4
RB
265 /* Identify the last token */
266 last_token = strrchr(absolute_path, '/');
267
268 /* Verify that this token is not a relative path */
269 is_dotdot = (strcmp(last_token, "/..") == 0);
270 is_dot = (strcmp(last_token, "/.") == 0);
271
272 /* If it is, take action */
273 if (is_dot || is_dotdot) {
274 /* For both, remove this token */
275 *last_token = '\0';
276
277 /* If it was a reference to parent directory, go back one more time */
278 if (is_dotdot) {
279 last_token = strrchr(absolute_path, '/');
280
281 /* If there was only one level left, we keep the first '/' */
282 if (last_token == absolute_path) {
283 last_token++;
284 }
285
286 *last_token = '\0';
287 }
288 }
289
3d229795 290 return absolute_path;
81b86775
DG
291
292error:
3d229795 293 free(absolute_path);
81b86775
DG
294 return NULL;
295}
296
297/*
298 * Create a pipe in dst.
299 */
90e535ef 300LTTNG_HIDDEN
81b86775
DG
301int utils_create_pipe(int *dst)
302{
303 int ret;
304
305 if (dst == NULL) {
306 return -1;
307 }
308
309 ret = pipe(dst);
310 if (ret < 0) {
311 PERROR("create pipe");
312 }
313
314 return ret;
315}
316
317/*
318 * Create pipe and set CLOEXEC flag to both fd.
319 *
320 * Make sure the pipe opened by this function are closed at some point. Use
321 * utils_close_pipe().
322 */
90e535ef 323LTTNG_HIDDEN
81b86775
DG
324int utils_create_pipe_cloexec(int *dst)
325{
326 int ret, i;
327
328 if (dst == NULL) {
329 return -1;
330 }
331
332 ret = utils_create_pipe(dst);
333 if (ret < 0) {
334 goto error;
335 }
336
337 for (i = 0; i < 2; i++) {
338 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
339 if (ret < 0) {
340 PERROR("fcntl pipe cloexec");
341 goto error;
342 }
343 }
344
345error:
346 return ret;
347}
348
094f381c
MD
349/*
350 * Create pipe and set fd flags to FD_CLOEXEC and O_NONBLOCK.
351 *
352 * Make sure the pipe opened by this function are closed at some point. Use
353 * utils_close_pipe(). Using pipe() and fcntl rather than pipe2() to
354 * support OSes other than Linux 2.6.23+.
355 */
356LTTNG_HIDDEN
357int utils_create_pipe_cloexec_nonblock(int *dst)
358{
359 int ret, i;
360
361 if (dst == NULL) {
362 return -1;
363 }
364
365 ret = utils_create_pipe(dst);
366 if (ret < 0) {
367 goto error;
368 }
369
370 for (i = 0; i < 2; i++) {
371 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
372 if (ret < 0) {
373 PERROR("fcntl pipe cloexec");
374 goto error;
375 }
376 /*
377 * Note: we override any flag that could have been
378 * previously set on the fd.
379 */
380 ret = fcntl(dst[i], F_SETFL, O_NONBLOCK);
381 if (ret < 0) {
382 PERROR("fcntl pipe nonblock");
383 goto error;
384 }
385 }
386
387error:
388 return ret;
389}
390
81b86775
DG
391/*
392 * Close both read and write side of the pipe.
393 */
90e535ef 394LTTNG_HIDDEN
81b86775
DG
395void utils_close_pipe(int *src)
396{
397 int i, ret;
398
399 if (src == NULL) {
400 return;
401 }
402
403 for (i = 0; i < 2; i++) {
404 /* Safety check */
405 if (src[i] < 0) {
406 continue;
407 }
408
409 ret = close(src[i]);
410 if (ret) {
411 PERROR("close pipe");
412 }
413 }
414}
a4b92340
DG
415
416/*
417 * Create a new string using two strings range.
418 */
90e535ef 419LTTNG_HIDDEN
a4b92340
DG
420char *utils_strdupdelim(const char *begin, const char *end)
421{
422 char *str;
423
424 str = zmalloc(end - begin + 1);
425 if (str == NULL) {
426 PERROR("zmalloc strdupdelim");
427 goto error;
428 }
429
430 memcpy(str, begin, end - begin);
431 str[end - begin] = '\0';
432
433error:
434 return str;
435}
b662582b
DG
436
437/*
438 * Set CLOEXEC flag to the give file descriptor.
439 */
90e535ef 440LTTNG_HIDDEN
b662582b
DG
441int utils_set_fd_cloexec(int fd)
442{
443 int ret;
444
445 if (fd < 0) {
446 ret = -EINVAL;
447 goto end;
448 }
449
450 ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
451 if (ret < 0) {
452 PERROR("fcntl cloexec");
453 ret = -errno;
454 }
455
456end:
457 return ret;
458}
35f90c40
DG
459
460/*
461 * Create pid file to the given path and filename.
462 */
90e535ef 463LTTNG_HIDDEN
35f90c40
DG
464int utils_create_pid_file(pid_t pid, const char *filepath)
465{
466 int ret;
467 FILE *fp;
468
469 assert(filepath);
470
471 fp = fopen(filepath, "w");
472 if (fp == NULL) {
473 PERROR("open pid file %s", filepath);
474 ret = -1;
475 goto error;
476 }
477
478 ret = fprintf(fp, "%d\n", pid);
479 if (ret < 0) {
480 PERROR("fprintf pid file");
e205d79b 481 goto error;
35f90c40
DG
482 }
483
e205d79b
MD
484 if (fclose(fp)) {
485 PERROR("fclose");
486 }
35f90c40 487 DBG("Pid %d written in file %s", pid, filepath);
e205d79b 488 ret = 0;
35f90c40
DG
489error:
490 return ret;
491}
2d851108 492
c9cb3e7d
JG
493/*
494 * Create lock file to the given path and filename.
495 * Returns the associated file descriptor, -1 on error.
496 */
497LTTNG_HIDDEN
498int utils_create_lock_file(const char *filepath)
499{
500 int ret;
501 int fd;
502
503 assert(filepath);
504
505 fd = open(filepath, O_CREAT,
506 O_WRONLY | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
507 if (fd < 0) {
508 PERROR("open lock file %s", filepath);
509 ret = -1;
510 goto error;
511 }
512
513 /*
514 * Attempt to lock the file. If this fails, there is
515 * already a process using the same lock file running
516 * and we should exit.
517 */
518 ret = flock(fd, LOCK_EX | LOCK_NB);
519 if (ret) {
208ff148 520 ERR("Could not get lock file %s, another instance is running.",
c9cb3e7d 521 filepath);
ffb0b851
JG
522 if (close(fd)) {
523 PERROR("close lock file");
524 }
c9cb3e7d
JG
525 fd = ret;
526 goto error;
527 }
528
529error:
530 return fd;
531}
532
2d851108
DG
533/*
534 * Recursively create directory using the given path and mode.
535 *
536 * On success, return 0 else a negative error code.
537 */
90e535ef 538LTTNG_HIDDEN
2d851108
DG
539int utils_mkdir_recursive(const char *path, mode_t mode)
540{
541 char *p, tmp[PATH_MAX];
2d851108
DG
542 size_t len;
543 int ret;
544
545 assert(path);
546
547 ret = snprintf(tmp, sizeof(tmp), "%s", path);
548 if (ret < 0) {
549 PERROR("snprintf mkdir");
550 goto error;
551 }
552
553 len = ret;
554 if (tmp[len - 1] == '/') {
555 tmp[len - 1] = 0;
556 }
557
558 for (p = tmp + 1; *p; p++) {
559 if (*p == '/') {
560 *p = 0;
561 if (tmp[strlen(tmp) - 1] == '.' &&
562 tmp[strlen(tmp) - 2] == '.' &&
563 tmp[strlen(tmp) - 3] == '/') {
564 ERR("Using '/../' is not permitted in the trace path (%s)",
565 tmp);
566 ret = -1;
567 goto error;
568 }
0c7bcad5 569 ret = mkdir(tmp, mode);
2d851108 570 if (ret < 0) {
0c7bcad5
MD
571 if (errno != EEXIST) {
572 PERROR("mkdir recursive");
573 ret = -errno;
574 goto error;
2d851108
DG
575 }
576 }
577 *p = '/';
578 }
579 }
580
581 ret = mkdir(tmp, mode);
582 if (ret < 0) {
583 if (errno != EEXIST) {
584 PERROR("mkdir recursive last piece");
585 ret = -errno;
586 } else {
587 ret = 0;
588 }
589 }
590
591error:
592 return ret;
593}
fe4477ee
JD
594
595/*
596 * Create the stream tracefile on disk.
597 *
598 * Return 0 on success or else a negative value.
599 */
bc182241 600LTTNG_HIDDEN
07b86b52 601int utils_create_stream_file(const char *path_name, char *file_name, uint64_t size,
309167d2 602 uint64_t count, int uid, int gid, char *suffix)
fe4477ee 603{
be96a7d1 604 int ret, out_fd, flags, mode;
309167d2
JD
605 char full_path[PATH_MAX], *path_name_suffix = NULL, *path;
606 char *extra = NULL;
fe4477ee
JD
607
608 assert(path_name);
609 assert(file_name);
610
611 ret = snprintf(full_path, sizeof(full_path), "%s/%s",
612 path_name, file_name);
613 if (ret < 0) {
614 PERROR("snprintf create output file");
615 goto error;
616 }
617
309167d2
JD
618 /* Setup extra string if suffix or/and a count is needed. */
619 if (size > 0 && suffix) {
620 ret = asprintf(&extra, "_%" PRIu64 "%s", count, suffix);
621 } else if (size > 0) {
622 ret = asprintf(&extra, "_%" PRIu64, count);
623 } else if (suffix) {
624 ret = asprintf(&extra, "%s", suffix);
625 }
626 if (ret < 0) {
627 PERROR("Allocating extra string to name");
628 goto error;
629 }
630
fe4477ee
JD
631 /*
632 * If we split the trace in multiple files, we have to add the count at the
633 * end of the tracefile name
634 */
309167d2
JD
635 if (extra) {
636 ret = asprintf(&path_name_suffix, "%s%s", full_path, extra);
fe4477ee 637 if (ret < 0) {
309167d2
JD
638 PERROR("Allocating path name with extra string");
639 goto error_free_suffix;
fe4477ee 640 }
309167d2 641 path = path_name_suffix;
fe4477ee
JD
642 } else {
643 path = full_path;
644 }
645
be96a7d1 646 flags = O_WRONLY | O_CREAT | O_TRUNC;
0f907de1 647 /* Open with 660 mode */
be96a7d1
DG
648 mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
649
650 if (uid < 0 || gid < 0) {
651 out_fd = open(path, flags, mode);
652 } else {
653 out_fd = run_as_open(path, flags, mode, uid, gid);
654 }
fe4477ee
JD
655 if (out_fd < 0) {
656 PERROR("open stream path %s", path);
657 goto error_open;
658 }
659 ret = out_fd;
660
661error_open:
309167d2
JD
662 free(path_name_suffix);
663error_free_suffix:
664 free(extra);
fe4477ee
JD
665error:
666 return ret;
667}
668
669/*
670 * Change the output tracefile according to the given size and count The
671 * new_count pointer is set during this operation.
672 *
673 * From the consumer, the stream lock MUST be held before calling this function
674 * because we are modifying the stream status.
675 *
676 * Return 0 on success or else a negative value.
677 */
bc182241 678LTTNG_HIDDEN
fe4477ee 679int utils_rotate_stream_file(char *path_name, char *file_name, uint64_t size,
309167d2
JD
680 uint64_t count, int uid, int gid, int out_fd, uint64_t *new_count,
681 int *stream_fd)
fe4477ee
JD
682{
683 int ret;
684
309167d2
JD
685 assert(new_count);
686 assert(stream_fd);
687
fe4477ee
JD
688 ret = close(out_fd);
689 if (ret < 0) {
690 PERROR("Closing tracefile");
691 goto error;
692 }
693
694 if (count > 0) {
695 *new_count = (*new_count + 1) % count;
696 } else {
697 (*new_count)++;
698 }
699
309167d2
JD
700 ret = utils_create_stream_file(path_name, file_name, size, *new_count,
701 uid, gid, 0);
702 if (ret < 0) {
703 goto error;
704 }
705 *stream_fd = ret;
706
707 /* Success. */
708 ret = 0;
709
fe4477ee
JD
710error:
711 return ret;
712}
70d0b120 713
70d0b120
SM
714
715/**
716 * Parse a string that represents a size in human readable format. It
5983a922 717 * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
70d0b120
SM
718 *
719 * The suffix multiply the integer by:
720 * 'k': 1024
721 * 'M': 1024^2
722 * 'G': 1024^3
723 *
724 * @param str The string to parse.
5983a922 725 * @param size Pointer to a uint64_t that will be filled with the
cfa9a5a2 726 * resulting size.
70d0b120
SM
727 *
728 * @return 0 on success, -1 on failure.
729 */
00a52467 730LTTNG_HIDDEN
5983a922 731int utils_parse_size_suffix(const char * const str, uint64_t * const size)
70d0b120 732{
70d0b120 733 int ret;
5983a922 734 uint64_t base_size;
70d0b120 735 long shift = 0;
5983a922
SM
736 const char *str_end;
737 char *num_end;
70d0b120
SM
738
739 if (!str) {
5983a922 740 DBG("utils_parse_size_suffix: received a NULL string.");
70d0b120
SM
741 ret = -1;
742 goto end;
743 }
744
5983a922
SM
745 /* strtoull will accept a negative number, but we don't want to. */
746 if (strchr(str, '-') != NULL) {
747 DBG("utils_parse_size_suffix: invalid size string, should not contain '-'.");
70d0b120 748 ret = -1;
5983a922 749 goto end;
70d0b120
SM
750 }
751
5983a922
SM
752 /* str_end will point to the \0 */
753 str_end = str + strlen(str);
70d0b120 754 errno = 0;
5983a922 755 base_size = strtoull(str, &num_end, 0);
70d0b120 756 if (errno != 0) {
5983a922 757 PERROR("utils_parse_size_suffix strtoull");
70d0b120 758 ret = -1;
5983a922
SM
759 goto end;
760 }
761
762 if (num_end == str) {
763 /* strtoull parsed nothing, not good. */
764 DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
765 ret = -1;
766 goto end;
767 }
768
769 /* Check if a prefix is present. */
770 switch (*num_end) {
771 case 'G':
772 shift = GIBI_LOG2;
773 num_end++;
774 break;
775 case 'M': /* */
776 shift = MEBI_LOG2;
777 num_end++;
778 break;
779 case 'K':
780 case 'k':
781 shift = KIBI_LOG2;
782 num_end++;
783 break;
784 case '\0':
785 break;
786 default:
787 DBG("utils_parse_size_suffix: invalid suffix.");
788 ret = -1;
789 goto end;
790 }
791
792 /* Check for garbage after the valid input. */
793 if (num_end != str_end) {
794 DBG("utils_parse_size_suffix: Garbage after size string.");
795 ret = -1;
796 goto end;
70d0b120
SM
797 }
798
799 *size = base_size << shift;
800
801 /* Check for overflow */
802 if ((*size >> shift) != base_size) {
5983a922 803 DBG("utils_parse_size_suffix: oops, overflow detected.");
70d0b120 804 ret = -1;
5983a922 805 goto end;
70d0b120
SM
806 }
807
808 ret = 0;
70d0b120
SM
809end:
810 return ret;
811}
cfa9a5a2
DG
812
813/*
814 * fls: returns the position of the most significant bit.
815 * Returns 0 if no bit is set, else returns the position of the most
816 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
817 */
818#if defined(__i386) || defined(__x86_64)
819static inline unsigned int fls_u32(uint32_t x)
820{
821 int r;
822
823 asm("bsrl %1,%0\n\t"
824 "jnz 1f\n\t"
825 "movl $-1,%0\n\t"
826 "1:\n\t"
827 : "=r" (r) : "rm" (x));
828 return r + 1;
829}
830#define HAS_FLS_U32
831#endif
832
833#ifndef HAS_FLS_U32
834static __attribute__((unused)) unsigned int fls_u32(uint32_t x)
835{
836 unsigned int r = 32;
837
838 if (!x) {
839 return 0;
840 }
841 if (!(x & 0xFFFF0000U)) {
842 x <<= 16;
843 r -= 16;
844 }
845 if (!(x & 0xFF000000U)) {
846 x <<= 8;
847 r -= 8;
848 }
849 if (!(x & 0xF0000000U)) {
850 x <<= 4;
851 r -= 4;
852 }
853 if (!(x & 0xC0000000U)) {
854 x <<= 2;
855 r -= 2;
856 }
857 if (!(x & 0x80000000U)) {
858 x <<= 1;
859 r -= 1;
860 }
861 return r;
862}
863#endif
864
865/*
866 * Return the minimum order for which x <= (1UL << order).
867 * Return -1 if x is 0.
868 */
869LTTNG_HIDDEN
870int utils_get_count_order_u32(uint32_t x)
871{
872 if (!x) {
873 return -1;
874 }
875
876 return fls_u32(x - 1);
877}
feb0f3e5
AM
878
879/**
880 * Obtain the value of LTTNG_HOME environment variable, if exists.
881 * Otherwise returns the value of HOME.
882 */
00a52467 883LTTNG_HIDDEN
feb0f3e5
AM
884char *utils_get_home_dir(void)
885{
886 char *val = NULL;
04135dbd
DG
887 struct passwd *pwd;
888
e8fa9fb0 889 val = lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
feb0f3e5 890 if (val != NULL) {
04135dbd
DG
891 goto end;
892 }
e8fa9fb0 893 val = lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
04135dbd
DG
894 if (val != NULL) {
895 goto end;
feb0f3e5 896 }
04135dbd
DG
897
898 /* Fallback on the password file entry. */
899 pwd = getpwuid(getuid());
900 if (!pwd) {
901 goto end;
902 }
903 val = pwd->pw_dir;
904
905 DBG3("Home directory is '%s'", val);
906
907end:
908 return val;
feb0f3e5 909}
26fe5938 910
fb198a11
JG
911/**
912 * Get user's home directory. Dynamically allocated, must be freed
913 * by the caller.
914 */
915LTTNG_HIDDEN
916char *utils_get_user_home_dir(uid_t uid)
917{
918 struct passwd pwd;
919 struct passwd *result;
920 char *home_dir = NULL;
921 char *buf = NULL;
922 long buflen;
923 int ret;
924
925 buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
926 if (buflen == -1) {
927 goto end;
928 }
929retry:
930 buf = zmalloc(buflen);
931 if (!buf) {
932 goto end;
933 }
934
935 ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
936 if (ret || !result) {
937 if (ret == ERANGE) {
938 free(buf);
939 buflen *= 2;
940 goto retry;
941 }
942 goto end;
943 }
944
945 home_dir = strdup(pwd.pw_dir);
946end:
947 free(buf);
948 return home_dir;
949}
950
fbb9748b
JG
951/*
952 * Obtain the value of LTTNG_KMOD_PROBES environment variable, if exists.
c9d42407 953 * Otherwise returns NULL.
fbb9748b
JG
954 */
955LTTNG_HIDDEN
956char *utils_get_kmod_probes_list(void)
957{
e8fa9fb0 958 return lttng_secure_getenv(DEFAULT_LTTNG_KMOD_PROBES);
fbb9748b
JG
959}
960
c9d42407
PP
961/*
962 * Obtain the value of LTTNG_EXTRA_KMOD_PROBES environment variable, if
963 * exists. Otherwise returns NULL.
964 */
965LTTNG_HIDDEN
966char *utils_get_extra_kmod_probes_list(void)
967{
e8fa9fb0 968 return lttng_secure_getenv(DEFAULT_LTTNG_EXTRA_KMOD_PROBES);
c9d42407
PP
969}
970
26fe5938
DG
971/*
972 * With the given format, fill dst with the time of len maximum siz.
973 *
974 * Return amount of bytes set in the buffer or else 0 on error.
975 */
976LTTNG_HIDDEN
977size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
978{
979 size_t ret;
980 time_t rawtime;
981 struct tm *timeinfo;
982
983 assert(format);
984 assert(dst);
985
986 /* Get date and time for session path */
987 time(&rawtime);
988 timeinfo = localtime(&rawtime);
989 ret = strftime(dst, len, format, timeinfo);
990 if (ret == 0) {
68e6efdd 991 ERR("Unable to strftime with format %s at dst %p of len %zu", format,
26fe5938
DG
992 dst, len);
993 }
994
995 return ret;
996}
6c71277b
MD
997
998/*
999 * Return the group ID matching name, else 0 if it cannot be found.
1000 */
1001LTTNG_HIDDEN
1002gid_t utils_get_group_id(const char *name)
1003{
1004 struct group *grp;
1005
1006 grp = getgrnam(name);
1007 if (!grp) {
1008 static volatile int warn_once;
1009
1010 if (!warn_once) {
1011 WARN("No tracing group detected");
1012 warn_once = 1;
1013 }
1014 return 0;
1015 }
1016 return grp->gr_gid;
1017}
8db0dc00
JG
1018
1019/*
1020 * Return a newly allocated option string. This string is to be used as the
1021 * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
1022 * of elements in the long_options array. Returns NULL if the string's
1023 * allocation fails.
1024 */
1025LTTNG_HIDDEN
1026char *utils_generate_optstring(const struct option *long_options,
1027 size_t opt_count)
1028{
1029 int i;
1030 size_t string_len = opt_count, str_pos = 0;
1031 char *optstring;
1032
1033 /*
1034 * Compute the necessary string length. One letter per option, two when an
1035 * argument is necessary, and a trailing NULL.
1036 */
1037 for (i = 0; i < opt_count; i++) {
1038 string_len += long_options[i].has_arg ? 1 : 0;
1039 }
1040
1041 optstring = zmalloc(string_len);
1042 if (!optstring) {
1043 goto end;
1044 }
1045
1046 for (i = 0; i < opt_count; i++) {
1047 if (!long_options[i].name) {
1048 /* Got to the trailing NULL element */
1049 break;
1050 }
1051
1052 optstring[str_pos++] = (char)long_options[i].val;
1053 if (long_options[i].has_arg) {
1054 optstring[str_pos++] = ':';
1055 }
1056 }
1057
1058end:
1059 return optstring;
1060}
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