Fix: kernel adds creds on recv with SO_PASSCRED unix socket option
[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
6c1c0768 20#define _LGPL_SOURCE
35f90c40 21#include <assert.h>
81b86775
DG
22#include <ctype.h>
23#include <fcntl.h>
24#include <limits.h>
25#include <stdlib.h>
2d851108 26#include <sys/stat.h>
0c7bcad5 27#include <sys/types.h>
2d851108 28#include <unistd.h>
fe4477ee 29#include <inttypes.h>
6c71277b 30#include <grp.h>
fb198a11 31#include <pwd.h>
c9cb3e7d 32#include <sys/file.h>
a98e236e 33#include <unistd.h>
81b86775
DG
34
35#include <common/common.h>
fe4477ee 36#include <common/runas.h>
e8fa9fb0 37#include <common/compat/getenv.h>
f5436bfc 38#include <common/compat/string.h>
5a2451c9 39#include <common/compat/dirent.h>
d7c23421 40#include <lttng/constant.h>
81b86775
DG
41
42#include "utils.h"
feb0f3e5 43#include "defaults.h"
81b86775 44
5154230f
RB
45/*
46 * Return a partial realpath(3) of the path even if the full path does not
47 * exist. For instance, with /tmp/test1/test2/test3, if test2/ does not exist
48 * but the /tmp/test1 does, the real path for /tmp/test1 is concatened with
49 * /test2/test3 then returned. In normal time, realpath(3) fails if the end
50 * point directory does not exist.
51 * In case resolved_path is NULL, the string returned was allocated in the
52 * function and thus need to be freed by the caller. The size argument allows
53 * to specify the size of the resolved_path argument if given, or the size to
54 * allocate.
55 */
56LTTNG_HIDDEN
57char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
58{
9482daac 59 char *cut_path = NULL, *try_path = NULL, *try_path_prev = NULL;
5154230f
RB
60 const char *next, *prev, *end;
61
62 /* Safety net */
63 if (path == NULL) {
64 goto error;
65 }
66
67 /*
68 * Identify the end of the path, we don't want to treat the
69 * last char if it is a '/', we will just keep it on the side
70 * to be added at the end, and return a value coherent with
71 * the path given as argument
72 */
73 end = path + strlen(path);
74 if (*(end-1) == '/') {
75 end--;
76 }
77
78 /* Initiate the values of the pointers before looping */
79 next = path;
80 prev = next;
81 /* Only to ensure try_path is not NULL to enter the while */
82 try_path = (char *)next;
83
84 /* Resolve the canonical path of the first part of the path */
85 while (try_path != NULL && next != end) {
d7c23421
JG
86 char *try_path_buf = NULL;
87
5154230f
RB
88 /*
89 * If there is not any '/' left, we want to try with
90 * the full path
91 */
92 next = strpbrk(next + 1, "/");
93 if (next == NULL) {
94 next = end;
95 }
96
97 /* Cut the part we will be trying to resolve */
f5436bfc 98 cut_path = lttng_strndup(path, next - path);
d9dbcf5e 99 if (cut_path == NULL) {
f5436bfc 100 PERROR("lttng_strndup");
d9dbcf5e
MD
101 goto error;
102 }
5154230f 103
d7c23421
JG
104 try_path_buf = zmalloc(LTTNG_PATH_MAX);
105 if (!try_path_buf) {
106 PERROR("zmalloc");
107 goto error;
108 }
109
5154230f 110 /* Try to resolve this part */
f3472d9a 111 try_path = realpath((char *) cut_path, try_path_buf);
5154230f 112 if (try_path == NULL) {
d7c23421 113 free(try_path_buf);
5154230f
RB
114 /*
115 * There was an error, we just want to be assured it
116 * is linked to an unexistent directory, if it's another
117 * reason, we spawn an error
118 */
119 switch (errno) {
120 case ENOENT:
121 /* Ignore the error */
122 break;
123 default:
124 PERROR("realpath (partial_realpath)");
125 goto error;
126 break;
127 }
128 } else {
129 /* Save the place we are before trying the next step */
d7c23421 130 try_path_buf = NULL;
5154230f
RB
131 free(try_path_prev);
132 try_path_prev = try_path;
133 prev = next;
134 }
135
136 /* Free the allocated memory */
137 free(cut_path);
c14cc491 138 cut_path = NULL;
494a8e99 139 }
5154230f
RB
140
141 /* Allocate memory for the resolved path if necessary */
142 if (resolved_path == NULL) {
143 resolved_path = zmalloc(size);
144 if (resolved_path == NULL) {
145 PERROR("zmalloc resolved path");
146 goto error;
147 }
148 }
149
150 /*
151 * If we were able to solve at least partially the path, we can concatenate
152 * what worked and what didn't work
153 */
154 if (try_path_prev != NULL) {
155 /* If we risk to concatenate two '/', we remove one of them */
156 if (try_path_prev[strlen(try_path_prev) - 1] == '/' && prev[0] == '/') {
157 try_path_prev[strlen(try_path_prev) - 1] = '\0';
158 }
159
160 /*
161 * Duplicate the memory used by prev in case resolved_path and
162 * path are pointers for the same memory space
163 */
164 cut_path = strdup(prev);
d9dbcf5e
MD
165 if (cut_path == NULL) {
166 PERROR("strdup");
167 goto error;
168 }
5154230f
RB
169
170 /* Concatenate the strings */
171 snprintf(resolved_path, size, "%s%s", try_path_prev, cut_path);
172
173 /* Free the allocated memory */
174 free(cut_path);
175 free(try_path_prev);
494a8e99
JG
176 cut_path = NULL;
177 try_path_prev = NULL;
5154230f
RB
178 /*
179 * Else, we just copy the path in our resolved_path to
180 * return it as is
181 */
182 } else {
183 strncpy(resolved_path, path, size);
184 }
185
186 /* Then we return the 'partially' resolved path */
187 return resolved_path;
188
189error:
190 free(resolved_path);
9482daac 191 free(cut_path);
b86d5f3f 192 free(try_path);
32bd4678
MJ
193 if (try_path_prev != try_path) {
194 free(try_path_prev);
195 }
5154230f
RB
196 return NULL;
197}
198
81b86775 199/*
3d229795
RB
200 * Make a full resolution of the given path even if it doesn't exist.
201 * This function uses the utils_partial_realpath function to resolve
202 * symlinks and relatives paths at the start of the string, and
203 * implements functionnalities to resolve the './' and '../' strings
204 * in the middle of a path. This function is only necessary because
205 * realpath(3) does not accept to resolve unexistent paths.
206 * The returned string was allocated in the function, it is thus of
207 * the responsibility of the caller to free this memory.
81b86775 208 */
90e535ef 209LTTNG_HIDDEN
81b86775
DG
210char *utils_expand_path(const char *path)
211{
3d229795 212 char *next, *previous, *slash, *start_path, *absolute_path = NULL;
5de083f4
RB
213 char *last_token;
214 int is_dot, is_dotdot;
81b86775
DG
215
216 /* Safety net */
217 if (path == NULL) {
218 goto error;
219 }
220
3d229795
RB
221 /* Allocate memory for the absolute_path */
222 absolute_path = zmalloc(PATH_MAX);
223 if (absolute_path == NULL) {
81b86775
DG
224 PERROR("zmalloc expand path");
225 goto error;
226 }
227
3d229795
RB
228 /*
229 * If the path is not already absolute nor explicitly relative,
230 * consider we're in the current directory
231 */
232 if (*path != '/' && strncmp(path, "./", 2) != 0 &&
233 strncmp(path, "../", 3) != 0) {
234 snprintf(absolute_path, PATH_MAX, "./%s", path);
2dcd84b7 235 /* Else, we just copy the path */
116f95d9 236 } else {
3d229795
RB
237 strncpy(absolute_path, path, PATH_MAX);
238 }
116f95d9 239
3d229795
RB
240 /* Resolve partially our path */
241 absolute_path = utils_partial_realpath(absolute_path,
242 absolute_path, PATH_MAX);
116f95d9 243
3d229795
RB
244 /* As long as we find '/./' in the working_path string */
245 while ((next = strstr(absolute_path, "/./"))) {
116f95d9 246
3d229795 247 /* We prepare the start_path not containing it */
f5436bfc 248 start_path = lttng_strndup(absolute_path, next - absolute_path);
d9dbcf5e 249 if (!start_path) {
f5436bfc 250 PERROR("lttng_strndup");
d9dbcf5e
MD
251 goto error;
252 }
3d229795
RB
253 /* And we concatenate it with the part after this string */
254 snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 2);
116f95d9 255
3d229795
RB
256 free(start_path);
257 }
116f95d9 258
3d229795
RB
259 /* As long as we find '/../' in the working_path string */
260 while ((next = strstr(absolute_path, "/../"))) {
261 /* We find the last level of directory */
262 previous = absolute_path;
263 while ((slash = strpbrk(previous, "/")) && slash != next) {
264 previous = slash + 1;
81b86775 265 }
81b86775 266
3d229795 267 /* Then we prepare the start_path not containing it */
f5436bfc 268 start_path = lttng_strndup(absolute_path, previous - absolute_path);
d9dbcf5e 269 if (!start_path) {
f5436bfc 270 PERROR("lttng_strndup");
d9dbcf5e
MD
271 goto error;
272 }
3d229795
RB
273
274 /* And we concatenate it with the part after the '/../' */
275 snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 4);
276
277 /* We can free the memory used for the start path*/
278 free(start_path);
279
280 /* Then we verify for symlinks using partial_realpath */
281 absolute_path = utils_partial_realpath(absolute_path,
282 absolute_path, PATH_MAX);
116f95d9 283 }
81b86775 284
5de083f4
RB
285 /* Identify the last token */
286 last_token = strrchr(absolute_path, '/');
287
288 /* Verify that this token is not a relative path */
289 is_dotdot = (strcmp(last_token, "/..") == 0);
290 is_dot = (strcmp(last_token, "/.") == 0);
291
292 /* If it is, take action */
293 if (is_dot || is_dotdot) {
294 /* For both, remove this token */
295 *last_token = '\0';
296
297 /* If it was a reference to parent directory, go back one more time */
298 if (is_dotdot) {
299 last_token = strrchr(absolute_path, '/');
300
301 /* If there was only one level left, we keep the first '/' */
302 if (last_token == absolute_path) {
303 last_token++;
304 }
305
306 *last_token = '\0';
307 }
308 }
309
3d229795 310 return absolute_path;
81b86775
DG
311
312error:
3d229795 313 free(absolute_path);
81b86775
DG
314 return NULL;
315}
316
317/*
318 * Create a pipe in dst.
319 */
90e535ef 320LTTNG_HIDDEN
81b86775
DG
321int utils_create_pipe(int *dst)
322{
323 int ret;
324
325 if (dst == NULL) {
326 return -1;
327 }
328
329 ret = pipe(dst);
330 if (ret < 0) {
331 PERROR("create pipe");
332 }
333
334 return ret;
335}
336
337/*
338 * Create pipe and set CLOEXEC flag to both fd.
339 *
340 * Make sure the pipe opened by this function are closed at some point. Use
341 * utils_close_pipe().
342 */
90e535ef 343LTTNG_HIDDEN
81b86775
DG
344int utils_create_pipe_cloexec(int *dst)
345{
346 int ret, i;
347
348 if (dst == NULL) {
349 return -1;
350 }
351
352 ret = utils_create_pipe(dst);
353 if (ret < 0) {
354 goto error;
355 }
356
357 for (i = 0; i < 2; i++) {
358 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
359 if (ret < 0) {
360 PERROR("fcntl pipe cloexec");
361 goto error;
362 }
363 }
364
365error:
366 return ret;
367}
368
094f381c
MD
369/*
370 * Create pipe and set fd flags to FD_CLOEXEC and O_NONBLOCK.
371 *
372 * Make sure the pipe opened by this function are closed at some point. Use
373 * utils_close_pipe(). Using pipe() and fcntl rather than pipe2() to
374 * support OSes other than Linux 2.6.23+.
375 */
376LTTNG_HIDDEN
377int utils_create_pipe_cloexec_nonblock(int *dst)
378{
379 int ret, i;
380
381 if (dst == NULL) {
382 return -1;
383 }
384
385 ret = utils_create_pipe(dst);
386 if (ret < 0) {
387 goto error;
388 }
389
390 for (i = 0; i < 2; i++) {
391 ret = fcntl(dst[i], F_SETFD, FD_CLOEXEC);
392 if (ret < 0) {
393 PERROR("fcntl pipe cloexec");
394 goto error;
395 }
396 /*
397 * Note: we override any flag that could have been
398 * previously set on the fd.
399 */
400 ret = fcntl(dst[i], F_SETFL, O_NONBLOCK);
401 if (ret < 0) {
402 PERROR("fcntl pipe nonblock");
403 goto error;
404 }
405 }
406
407error:
408 return ret;
409}
410
81b86775
DG
411/*
412 * Close both read and write side of the pipe.
413 */
90e535ef 414LTTNG_HIDDEN
81b86775
DG
415void utils_close_pipe(int *src)
416{
417 int i, ret;
418
419 if (src == NULL) {
420 return;
421 }
422
423 for (i = 0; i < 2; i++) {
424 /* Safety check */
425 if (src[i] < 0) {
426 continue;
427 }
428
429 ret = close(src[i]);
430 if (ret) {
431 PERROR("close pipe");
432 }
433 }
434}
a4b92340
DG
435
436/*
437 * Create a new string using two strings range.
438 */
90e535ef 439LTTNG_HIDDEN
a4b92340
DG
440char *utils_strdupdelim(const char *begin, const char *end)
441{
442 char *str;
443
444 str = zmalloc(end - begin + 1);
445 if (str == NULL) {
446 PERROR("zmalloc strdupdelim");
447 goto error;
448 }
449
450 memcpy(str, begin, end - begin);
451 str[end - begin] = '\0';
452
453error:
454 return str;
455}
b662582b
DG
456
457/*
458 * Set CLOEXEC flag to the give file descriptor.
459 */
90e535ef 460LTTNG_HIDDEN
b662582b
DG
461int utils_set_fd_cloexec(int fd)
462{
463 int ret;
464
465 if (fd < 0) {
466 ret = -EINVAL;
467 goto end;
468 }
469
470 ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
471 if (ret < 0) {
472 PERROR("fcntl cloexec");
473 ret = -errno;
474 }
475
476end:
477 return ret;
478}
35f90c40
DG
479
480/*
481 * Create pid file to the given path and filename.
482 */
90e535ef 483LTTNG_HIDDEN
35f90c40
DG
484int utils_create_pid_file(pid_t pid, const char *filepath)
485{
486 int ret;
487 FILE *fp;
488
489 assert(filepath);
490
491 fp = fopen(filepath, "w");
492 if (fp == NULL) {
493 PERROR("open pid file %s", filepath);
494 ret = -1;
495 goto error;
496 }
497
d1f721c5 498 ret = fprintf(fp, "%d\n", (int) pid);
35f90c40
DG
499 if (ret < 0) {
500 PERROR("fprintf pid file");
e205d79b 501 goto error;
35f90c40
DG
502 }
503
e205d79b
MD
504 if (fclose(fp)) {
505 PERROR("fclose");
506 }
d1f721c5 507 DBG("Pid %d written in file %s", (int) pid, filepath);
e205d79b 508 ret = 0;
35f90c40
DG
509error:
510 return ret;
511}
2d851108 512
c9cb3e7d
JG
513/*
514 * Create lock file to the given path and filename.
515 * Returns the associated file descriptor, -1 on error.
516 */
517LTTNG_HIDDEN
518int utils_create_lock_file(const char *filepath)
519{
520 int ret;
521 int fd;
77e7fddf 522 struct flock lock;
c9cb3e7d
JG
523
524 assert(filepath);
525
77e7fddf
MJ
526 memset(&lock, 0, sizeof(lock));
527 fd = open(filepath, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR |
528 S_IRGRP | S_IWGRP);
c9cb3e7d
JG
529 if (fd < 0) {
530 PERROR("open lock file %s", filepath);
e6576ba2 531 fd = -1;
c9cb3e7d
JG
532 goto error;
533 }
534
535 /*
536 * Attempt to lock the file. If this fails, there is
537 * already a process using the same lock file running
538 * and we should exit.
539 */
77e7fddf
MJ
540 lock.l_whence = SEEK_SET;
541 lock.l_type = F_WRLCK;
542
543 ret = fcntl(fd, F_SETLK, &lock);
544 if (ret == -1) {
545 PERROR("fcntl lock file");
208ff148 546 ERR("Could not get lock file %s, another instance is running.",
c9cb3e7d 547 filepath);
ffb0b851
JG
548 if (close(fd)) {
549 PERROR("close lock file");
550 }
c9cb3e7d
JG
551 fd = ret;
552 goto error;
553 }
554
555error:
556 return fd;
557}
558
a98e236e
JG
559/*
560 * On some filesystems (e.g. nfs), mkdir will validate access rights before
561 * checking for the existence of the path element. This means that on a setup
562 * where "/home/" is a mounted NFS share, and running as an unpriviledged user,
563 * recursively creating a path of the form "/home/my_user/trace/" will fail with
564 * EACCES on mkdir("/home", ...).
565 *
566 * Performing a stat(...) on the path to check for existence allows us to
567 * work around this behaviour.
568 */
569static
570int mkdir_check_exists(const char *path, mode_t mode)
571{
572 int ret = 0;
573 struct stat st;
574
575 ret = stat(path, &st);
576 if (ret == 0) {
577 if (S_ISDIR(st.st_mode)) {
578 /* Directory exists, skip. */
579 goto end;
580 } else {
581 /* Exists, but is not a directory. */
582 errno = ENOTDIR;
583 ret = -1;
584 goto end;
585 }
586 }
587
588 /*
589 * Let mkdir handle other errors as the caller expects mkdir
590 * semantics.
591 */
592 ret = mkdir(path, mode);
593end:
594 return ret;
595}
596
2d851108 597/*
d77dded2 598 * Create directory using the given path and mode.
2d851108
DG
599 *
600 * On success, return 0 else a negative error code.
601 */
90e535ef 602LTTNG_HIDDEN
d77dded2
JG
603int utils_mkdir(const char *path, mode_t mode, int uid, int gid)
604{
605 int ret;
606
607 if (uid < 0 || gid < 0) {
a98e236e 608 ret = mkdir_check_exists(path, mode);
d77dded2
JG
609 } else {
610 ret = run_as_mkdir(path, mode, uid, gid);
611 }
612 if (ret < 0) {
613 if (errno != EEXIST) {
614 PERROR("mkdir %s, uid %d, gid %d", path ? path : "NULL",
615 uid, gid);
616 } else {
617 ret = 0;
618 }
619 }
620
621 return ret;
622}
623
624/*
625 * Internal version of mkdir_recursive. Runs as the current user.
626 * Don't call directly; use utils_mkdir_recursive().
627 *
628 * This function is ominously marked as "unsafe" since it should only
629 * be called by a caller that has transitioned to the uid and gid under which
630 * the directory creation should occur.
631 */
632LTTNG_HIDDEN
633int _utils_mkdir_recursive_unsafe(const char *path, mode_t mode)
2d851108
DG
634{
635 char *p, tmp[PATH_MAX];
2d851108
DG
636 size_t len;
637 int ret;
638
639 assert(path);
640
641 ret = snprintf(tmp, sizeof(tmp), "%s", path);
642 if (ret < 0) {
643 PERROR("snprintf mkdir");
644 goto error;
645 }
646
647 len = ret;
648 if (tmp[len - 1] == '/') {
649 tmp[len - 1] = 0;
650 }
651
652 for (p = tmp + 1; *p; p++) {
653 if (*p == '/') {
654 *p = 0;
655 if (tmp[strlen(tmp) - 1] == '.' &&
656 tmp[strlen(tmp) - 2] == '.' &&
657 tmp[strlen(tmp) - 3] == '/') {
658 ERR("Using '/../' is not permitted in the trace path (%s)",
659 tmp);
660 ret = -1;
661 goto error;
662 }
a98e236e 663 ret = mkdir_check_exists(tmp, mode);
2d851108 664 if (ret < 0) {
a98e236e 665 if (errno != EACCES) {
0c7bcad5
MD
666 PERROR("mkdir recursive");
667 ret = -errno;
668 goto error;
2d851108
DG
669 }
670 }
671 *p = '/';
672 }
673 }
674
a98e236e 675 ret = mkdir_check_exists(tmp, mode);
2d851108 676 if (ret < 0) {
a98e236e
JG
677 PERROR("mkdir recursive last element");
678 ret = -errno;
2d851108
DG
679 }
680
681error:
682 return ret;
683}
fe4477ee 684
d77dded2
JG
685/*
686 * Recursively create directory using the given path and mode, under the
687 * provided uid and gid.
688 *
689 * On success, return 0 else a negative error code.
690 */
691LTTNG_HIDDEN
692int utils_mkdir_recursive(const char *path, mode_t mode, int uid, int gid)
693{
694 int ret;
695
696 if (uid < 0 || gid < 0) {
697 /* Run as current user. */
698 ret = _utils_mkdir_recursive_unsafe(path, mode);
699 } else {
700 ret = run_as_mkdir_recursive(path, mode, uid, gid);
701 }
702 if (ret < 0) {
703 PERROR("mkdir %s, uid %d, gid %d", path ? path : "NULL",
704 uid, gid);
705 }
706
707 return ret;
708}
709
fe4477ee 710/*
d77dded2 711 * path is the output parameter. It needs to be PATH_MAX len.
fe4477ee
JD
712 *
713 * Return 0 on success or else a negative value.
714 */
7591bab1
MD
715static int utils_stream_file_name(char *path,
716 const char *path_name, const char *file_name,
717 uint64_t size, uint64_t count,
718 const char *suffix)
fe4477ee 719{
7591bab1
MD
720 int ret;
721 char full_path[PATH_MAX];
722 char *path_name_suffix = NULL;
309167d2 723 char *extra = NULL;
fe4477ee 724
fe4477ee
JD
725 ret = snprintf(full_path, sizeof(full_path), "%s/%s",
726 path_name, file_name);
727 if (ret < 0) {
728 PERROR("snprintf create output file");
729 goto error;
730 }
731
309167d2
JD
732 /* Setup extra string if suffix or/and a count is needed. */
733 if (size > 0 && suffix) {
734 ret = asprintf(&extra, "_%" PRIu64 "%s", count, suffix);
735 } else if (size > 0) {
736 ret = asprintf(&extra, "_%" PRIu64, count);
737 } else if (suffix) {
738 ret = asprintf(&extra, "%s", suffix);
739 }
740 if (ret < 0) {
741 PERROR("Allocating extra string to name");
742 goto error;
743 }
744
fe4477ee 745 /*
7591bab1
MD
746 * If we split the trace in multiple files, we have to add the count at
747 * the end of the tracefile name.
fe4477ee 748 */
309167d2
JD
749 if (extra) {
750 ret = asprintf(&path_name_suffix, "%s%s", full_path, extra);
fe4477ee 751 if (ret < 0) {
309167d2
JD
752 PERROR("Allocating path name with extra string");
753 goto error_free_suffix;
fe4477ee 754 }
7591bab1
MD
755 strncpy(path, path_name_suffix, PATH_MAX - 1);
756 path[PATH_MAX - 1] = '\0';
fe4477ee 757 } else {
072ede59
JG
758 ret = lttng_strncpy(path, full_path, PATH_MAX);
759 if (ret) {
760 ERR("Failed to copy stream file name");
761 goto error_free_suffix;
762 }
7591bab1
MD
763 }
764 path[PATH_MAX - 1] = '\0';
765 ret = 0;
766
767 free(path_name_suffix);
768error_free_suffix:
769 free(extra);
770error:
771 return ret;
772}
773
774/*
775 * Create the stream file on disk.
776 *
777 * Return 0 on success or else a negative value.
778 */
779LTTNG_HIDDEN
780int utils_create_stream_file(const char *path_name, char *file_name, uint64_t size,
781 uint64_t count, int uid, int gid, char *suffix)
782{
783 int ret, flags, mode;
784 char path[PATH_MAX];
785
786 ret = utils_stream_file_name(path, path_name, file_name,
787 size, count, suffix);
788 if (ret < 0) {
789 goto error;
fe4477ee
JD
790 }
791
d3ecc550
JD
792 /*
793 * With the session rotation feature on the relay, we might need to seek
794 * and truncate a tracefile, so we need read and write access.
795 */
796 flags = O_RDWR | O_CREAT | O_TRUNC;
0f907de1 797 /* Open with 660 mode */
be96a7d1
DG
798 mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
799
800 if (uid < 0 || gid < 0) {
7591bab1 801 ret = open(path, flags, mode);
be96a7d1 802 } else {
7591bab1 803 ret = run_as_open(path, flags, mode, uid, gid);
be96a7d1 804 }
7591bab1 805 if (ret < 0) {
fe4477ee 806 PERROR("open stream path %s", path);
fe4477ee 807 }
7591bab1
MD
808error:
809 return ret;
810}
fe4477ee 811
7591bab1
MD
812/*
813 * Unlink the stream tracefile from disk.
814 *
815 * Return 0 on success or else a negative value.
816 */
817LTTNG_HIDDEN
818int utils_unlink_stream_file(const char *path_name, char *file_name, uint64_t size,
819 uint64_t count, int uid, int gid, char *suffix)
820{
821 int ret;
822 char path[PATH_MAX];
823
824 ret = utils_stream_file_name(path, path_name, file_name,
825 size, count, suffix);
826 if (ret < 0) {
827 goto error;
828 }
829 if (uid < 0 || gid < 0) {
830 ret = unlink(path);
831 } else {
832 ret = run_as_unlink(path, uid, gid);
7591bab1
MD
833 }
834 if (ret < 0) {
835 goto error;
836 }
fe4477ee 837error:
7591bab1 838 DBG("utils_unlink_stream_file %s returns %d", path, ret);
fe4477ee
JD
839 return ret;
840}
841
842/*
843 * Change the output tracefile according to the given size and count The
844 * new_count pointer is set during this operation.
845 *
846 * From the consumer, the stream lock MUST be held before calling this function
847 * because we are modifying the stream status.
848 *
849 * Return 0 on success or else a negative value.
850 */
bc182241 851LTTNG_HIDDEN
fe4477ee 852int utils_rotate_stream_file(char *path_name, char *file_name, uint64_t size,
309167d2
JD
853 uint64_t count, int uid, int gid, int out_fd, uint64_t *new_count,
854 int *stream_fd)
fe4477ee
JD
855{
856 int ret;
857
309167d2
JD
858 assert(stream_fd);
859
fe4477ee
JD
860 ret = close(out_fd);
861 if (ret < 0) {
862 PERROR("Closing tracefile");
863 goto error;
864 }
b5b0c181 865 *stream_fd = -1;
fe4477ee
JD
866
867 if (count > 0) {
7591bab1
MD
868 /*
869 * In tracefile rotation, for the relay daemon we need
870 * to unlink the old file if present, because it may
871 * still be open in reading by the live thread, and we
872 * need to ensure that we do not overwrite the content
873 * between get_index and get_packet. Since we have no
874 * way to verify integrity of the data content compared
875 * to the associated index, we need to ensure the reader
876 * has exclusive access to the file content, and that
877 * the open of the data file is performed in get_index.
878 * Unlinking the old file rather than overwriting it
879 * achieves this.
880 */
93ec662e
JD
881 if (new_count) {
882 *new_count = (*new_count + 1) % count;
883 }
884 ret = utils_unlink_stream_file(path_name, file_name, size,
885 new_count ? *new_count : 0, uid, gid, 0);
7591bab1
MD
886 if (ret < 0 && errno != ENOENT) {
887 goto error;
888 }
fe4477ee 889 } else {
93ec662e
JD
890 if (new_count) {
891 (*new_count)++;
892 }
fe4477ee
JD
893 }
894
93ec662e
JD
895 ret = utils_create_stream_file(path_name, file_name, size,
896 new_count ? *new_count : 0, uid, gid, 0);
309167d2
JD
897 if (ret < 0) {
898 goto error;
899 }
900 *stream_fd = ret;
901
902 /* Success. */
903 ret = 0;
904
fe4477ee
JD
905error:
906 return ret;
907}
70d0b120 908
70d0b120
SM
909
910/**
911 * Parse a string that represents a size in human readable format. It
5983a922 912 * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
70d0b120
SM
913 *
914 * The suffix multiply the integer by:
915 * 'k': 1024
916 * 'M': 1024^2
917 * 'G': 1024^3
918 *
919 * @param str The string to parse.
5983a922 920 * @param size Pointer to a uint64_t that will be filled with the
cfa9a5a2 921 * resulting size.
70d0b120
SM
922 *
923 * @return 0 on success, -1 on failure.
924 */
00a52467 925LTTNG_HIDDEN
5983a922 926int utils_parse_size_suffix(const char * const str, uint64_t * const size)
70d0b120 927{
70d0b120 928 int ret;
5983a922 929 uint64_t base_size;
70d0b120 930 long shift = 0;
5983a922
SM
931 const char *str_end;
932 char *num_end;
70d0b120
SM
933
934 if (!str) {
5983a922 935 DBG("utils_parse_size_suffix: received a NULL string.");
70d0b120
SM
936 ret = -1;
937 goto end;
938 }
939
5983a922
SM
940 /* strtoull will accept a negative number, but we don't want to. */
941 if (strchr(str, '-') != NULL) {
942 DBG("utils_parse_size_suffix: invalid size string, should not contain '-'.");
70d0b120 943 ret = -1;
5983a922 944 goto end;
70d0b120
SM
945 }
946
5983a922
SM
947 /* str_end will point to the \0 */
948 str_end = str + strlen(str);
70d0b120 949 errno = 0;
5983a922 950 base_size = strtoull(str, &num_end, 0);
70d0b120 951 if (errno != 0) {
5983a922 952 PERROR("utils_parse_size_suffix strtoull");
70d0b120 953 ret = -1;
5983a922
SM
954 goto end;
955 }
956
957 if (num_end == str) {
958 /* strtoull parsed nothing, not good. */
959 DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
960 ret = -1;
961 goto end;
962 }
963
964 /* Check if a prefix is present. */
965 switch (*num_end) {
966 case 'G':
967 shift = GIBI_LOG2;
968 num_end++;
969 break;
970 case 'M': /* */
971 shift = MEBI_LOG2;
972 num_end++;
973 break;
974 case 'K':
975 case 'k':
976 shift = KIBI_LOG2;
977 num_end++;
978 break;
979 case '\0':
980 break;
981 default:
982 DBG("utils_parse_size_suffix: invalid suffix.");
983 ret = -1;
984 goto end;
985 }
986
987 /* Check for garbage after the valid input. */
988 if (num_end != str_end) {
989 DBG("utils_parse_size_suffix: Garbage after size string.");
990 ret = -1;
991 goto end;
70d0b120
SM
992 }
993
994 *size = base_size << shift;
995
996 /* Check for overflow */
997 if ((*size >> shift) != base_size) {
5983a922 998 DBG("utils_parse_size_suffix: oops, overflow detected.");
70d0b120 999 ret = -1;
5983a922 1000 goto end;
70d0b120
SM
1001 }
1002
1003 ret = 0;
70d0b120
SM
1004end:
1005 return ret;
1006}
cfa9a5a2 1007
7010c033
SM
1008/**
1009 * Parse a string that represents a time in human readable format. It
1010 * supports decimal integers suffixed by 's', 'u', 'm', 'us', and 'ms'.
1011 *
1012 * The suffix multiply the integer by:
1013 * 'u'/'us': 1
1014 * 'm'/'ms': 1000
1015 * 's': 1000000
1016 *
1017 * Note that unit-less numbers are assumed to be microseconds.
1018 *
1019 * @param str The string to parse, assumed to be NULL-terminated.
1020 * @param time_us Pointer to a uint64_t that will be filled with the
1021 * resulting time in microseconds.
1022 *
1023 * @return 0 on success, -1 on failure.
1024 */
1025LTTNG_HIDDEN
1026int utils_parse_time_suffix(char const * const str, uint64_t * const time_us)
1027{
1028 int ret;
1029 uint64_t base_time;
1030 long multiplier = 1;
1031 const char *str_end;
1032 char *num_end;
1033
1034 if (!str) {
1035 DBG("utils_parse_time_suffix: received a NULL string.");
1036 ret = -1;
1037 goto end;
1038 }
1039
1040 /* strtoull will accept a negative number, but we don't want to. */
1041 if (strchr(str, '-') != NULL) {
1042 DBG("utils_parse_time_suffix: invalid time string, should not contain '-'.");
1043 ret = -1;
1044 goto end;
1045 }
1046
1047 /* str_end will point to the \0 */
1048 str_end = str + strlen(str);
1049 errno = 0;
1050 base_time = strtoull(str, &num_end, 10);
1051 if (errno != 0) {
1052 PERROR("utils_parse_time_suffix strtoull on string \"%s\"", str);
1053 ret = -1;
1054 goto end;
1055 }
1056
1057 if (num_end == str) {
1058 /* strtoull parsed nothing, not good. */
1059 DBG("utils_parse_time_suffix: strtoull had nothing good to parse.");
1060 ret = -1;
1061 goto end;
1062 }
1063
1064 /* Check if a prefix is present. */
1065 switch (*num_end) {
1066 case 'u':
1067 multiplier = 1;
1068 /* Skip another letter in the 'us' case. */
1069 num_end += (*(num_end + 1) == 's') ? 2 : 1;
1070 break;
1071 case 'm':
1072 multiplier = 1000;
1073 /* Skip another letter in the 'ms' case. */
1074 num_end += (*(num_end + 1) == 's') ? 2 : 1;
1075 break;
1076 case 's':
1077 multiplier = 1000000;
1078 num_end++;
1079 break;
1080 case '\0':
1081 break;
1082 default:
1083 DBG("utils_parse_time_suffix: invalid suffix.");
1084 ret = -1;
1085 goto end;
1086 }
1087
1088 /* Check for garbage after the valid input. */
1089 if (num_end != str_end) {
1090 DBG("utils_parse_time_suffix: Garbage after time string.");
1091 ret = -1;
1092 goto end;
1093 }
1094
1095 *time_us = base_time * multiplier;
1096
1097 /* Check for overflow */
1098 if ((*time_us / multiplier) != base_time) {
1099 DBG("utils_parse_time_suffix: oops, overflow detected.");
1100 ret = -1;
1101 goto end;
1102 }
1103
1104 ret = 0;
1105end:
1106 return ret;
1107}
1108
cfa9a5a2
DG
1109/*
1110 * fls: returns the position of the most significant bit.
1111 * Returns 0 if no bit is set, else returns the position of the most
1112 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
1113 */
1114#if defined(__i386) || defined(__x86_64)
1115static inline unsigned int fls_u32(uint32_t x)
1116{
1117 int r;
1118
1119 asm("bsrl %1,%0\n\t"
1120 "jnz 1f\n\t"
1121 "movl $-1,%0\n\t"
1122 "1:\n\t"
1123 : "=r" (r) : "rm" (x));
1124 return r + 1;
1125}
1126#define HAS_FLS_U32
1127#endif
1128
db5be0a3
JG
1129#if defined(__x86_64)
1130static inline
1131unsigned int fls_u64(uint64_t x)
1132{
1133 long r;
1134
1135 asm("bsrq %1,%0\n\t"
1136 "jnz 1f\n\t"
1137 "movq $-1,%0\n\t"
1138 "1:\n\t"
1139 : "=r" (r) : "rm" (x));
1140 return r + 1;
1141}
1142#define HAS_FLS_U64
1143#endif
1144
1145#ifndef HAS_FLS_U64
1146static __attribute__((unused))
1147unsigned int fls_u64(uint64_t x)
1148{
1149 unsigned int r = 64;
1150
1151 if (!x)
1152 return 0;
1153
1154 if (!(x & 0xFFFFFFFF00000000ULL)) {
1155 x <<= 32;
1156 r -= 32;
1157 }
1158 if (!(x & 0xFFFF000000000000ULL)) {
1159 x <<= 16;
1160 r -= 16;
1161 }
1162 if (!(x & 0xFF00000000000000ULL)) {
1163 x <<= 8;
1164 r -= 8;
1165 }
1166 if (!(x & 0xF000000000000000ULL)) {
1167 x <<= 4;
1168 r -= 4;
1169 }
1170 if (!(x & 0xC000000000000000ULL)) {
1171 x <<= 2;
1172 r -= 2;
1173 }
1174 if (!(x & 0x8000000000000000ULL)) {
1175 x <<= 1;
1176 r -= 1;
1177 }
1178 return r;
1179}
1180#endif
1181
cfa9a5a2
DG
1182#ifndef HAS_FLS_U32
1183static __attribute__((unused)) unsigned int fls_u32(uint32_t x)
1184{
1185 unsigned int r = 32;
1186
1187 if (!x) {
1188 return 0;
1189 }
1190 if (!(x & 0xFFFF0000U)) {
1191 x <<= 16;
1192 r -= 16;
1193 }
1194 if (!(x & 0xFF000000U)) {
1195 x <<= 8;
1196 r -= 8;
1197 }
1198 if (!(x & 0xF0000000U)) {
1199 x <<= 4;
1200 r -= 4;
1201 }
1202 if (!(x & 0xC0000000U)) {
1203 x <<= 2;
1204 r -= 2;
1205 }
1206 if (!(x & 0x80000000U)) {
1207 x <<= 1;
1208 r -= 1;
1209 }
1210 return r;
1211}
1212#endif
1213
1214/*
1215 * Return the minimum order for which x <= (1UL << order).
1216 * Return -1 if x is 0.
1217 */
1218LTTNG_HIDDEN
1219int utils_get_count_order_u32(uint32_t x)
1220{
1221 if (!x) {
1222 return -1;
1223 }
1224
1225 return fls_u32(x - 1);
1226}
feb0f3e5 1227
db5be0a3
JG
1228/*
1229 * Return the minimum order for which x <= (1UL << order).
1230 * Return -1 if x is 0.
1231 */
1232LTTNG_HIDDEN
1233int utils_get_count_order_u64(uint64_t x)
1234{
1235 if (!x) {
1236 return -1;
1237 }
1238
1239 return fls_u64(x - 1);
1240}
1241
feb0f3e5
AM
1242/**
1243 * Obtain the value of LTTNG_HOME environment variable, if exists.
1244 * Otherwise returns the value of HOME.
1245 */
00a52467 1246LTTNG_HIDDEN
feb0f3e5
AM
1247char *utils_get_home_dir(void)
1248{
1249 char *val = NULL;
04135dbd
DG
1250 struct passwd *pwd;
1251
e8fa9fb0 1252 val = lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
feb0f3e5 1253 if (val != NULL) {
04135dbd
DG
1254 goto end;
1255 }
e8fa9fb0 1256 val = lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
04135dbd
DG
1257 if (val != NULL) {
1258 goto end;
feb0f3e5 1259 }
04135dbd
DG
1260
1261 /* Fallback on the password file entry. */
1262 pwd = getpwuid(getuid());
1263 if (!pwd) {
1264 goto end;
1265 }
1266 val = pwd->pw_dir;
1267
1268 DBG3("Home directory is '%s'", val);
1269
1270end:
1271 return val;
feb0f3e5 1272}
26fe5938 1273
fb198a11
JG
1274/**
1275 * Get user's home directory. Dynamically allocated, must be freed
1276 * by the caller.
1277 */
1278LTTNG_HIDDEN
1279char *utils_get_user_home_dir(uid_t uid)
1280{
1281 struct passwd pwd;
1282 struct passwd *result;
1283 char *home_dir = NULL;
1284 char *buf = NULL;
1285 long buflen;
1286 int ret;
1287
1288 buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
1289 if (buflen == -1) {
1290 goto end;
1291 }
1292retry:
1293 buf = zmalloc(buflen);
1294 if (!buf) {
1295 goto end;
1296 }
1297
1298 ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
1299 if (ret || !result) {
1300 if (ret == ERANGE) {
1301 free(buf);
1302 buflen *= 2;
1303 goto retry;
1304 }
1305 goto end;
1306 }
1307
1308 home_dir = strdup(pwd.pw_dir);
1309end:
1310 free(buf);
1311 return home_dir;
1312}
1313
26fe5938
DG
1314/*
1315 * With the given format, fill dst with the time of len maximum siz.
1316 *
1317 * Return amount of bytes set in the buffer or else 0 on error.
1318 */
1319LTTNG_HIDDEN
1320size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
1321{
1322 size_t ret;
1323 time_t rawtime;
1324 struct tm *timeinfo;
1325
1326 assert(format);
1327 assert(dst);
1328
1329 /* Get date and time for session path */
1330 time(&rawtime);
1331 timeinfo = localtime(&rawtime);
1332 ret = strftime(dst, len, format, timeinfo);
1333 if (ret == 0) {
68e6efdd 1334 ERR("Unable to strftime with format %s at dst %p of len %zu", format,
26fe5938
DG
1335 dst, len);
1336 }
1337
1338 return ret;
1339}
6c71277b
MD
1340
1341/*
1342 * Return the group ID matching name, else 0 if it cannot be found.
1343 */
1344LTTNG_HIDDEN
1345gid_t utils_get_group_id(const char *name)
1346{
1347 struct group *grp;
1348
1349 grp = getgrnam(name);
1350 if (!grp) {
1351 static volatile int warn_once;
1352
1353 if (!warn_once) {
1354 WARN("No tracing group detected");
1355 warn_once = 1;
1356 }
1357 return 0;
1358 }
1359 return grp->gr_gid;
1360}
8db0dc00
JG
1361
1362/*
1363 * Return a newly allocated option string. This string is to be used as the
1364 * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
1365 * of elements in the long_options array. Returns NULL if the string's
1366 * allocation fails.
1367 */
1368LTTNG_HIDDEN
1369char *utils_generate_optstring(const struct option *long_options,
1370 size_t opt_count)
1371{
1372 int i;
1373 size_t string_len = opt_count, str_pos = 0;
1374 char *optstring;
1375
1376 /*
1377 * Compute the necessary string length. One letter per option, two when an
1378 * argument is necessary, and a trailing NULL.
1379 */
1380 for (i = 0; i < opt_count; i++) {
1381 string_len += long_options[i].has_arg ? 1 : 0;
1382 }
1383
1384 optstring = zmalloc(string_len);
1385 if (!optstring) {
1386 goto end;
1387 }
1388
1389 for (i = 0; i < opt_count; i++) {
1390 if (!long_options[i].name) {
1391 /* Got to the trailing NULL element */
1392 break;
1393 }
1394
a596dcb9
JG
1395 if (long_options[i].val != '\0') {
1396 optstring[str_pos++] = (char) long_options[i].val;
1397 if (long_options[i].has_arg) {
1398 optstring[str_pos++] = ':';
1399 }
8db0dc00
JG
1400 }
1401 }
1402
1403end:
1404 return optstring;
1405}
3d071855
MD
1406
1407/*
1408 * Try to remove a hierarchy of empty directories, recursively. Don't unlink
9529ec1b 1409 * any file. Try to rmdir any empty directory within the hierarchy.
3d071855
MD
1410 */
1411LTTNG_HIDDEN
1412int utils_recursive_rmdir(const char *path)
1413{
1414 DIR *dir;
7a946beb 1415 size_t path_len;
9529ec1b 1416 int dir_fd, ret = 0, closeret, is_empty = 1;
3d071855
MD
1417 struct dirent *entry;
1418
1419 /* Open directory */
1420 dir = opendir(path);
1421 if (!dir) {
1422 PERROR("Cannot open '%s' path", path);
1423 return -1;
1424 }
5a2451c9 1425 dir_fd = lttng_dirfd(dir);
3d071855 1426 if (dir_fd < 0) {
5a2451c9 1427 PERROR("lttng_dirfd");
3d071855
MD
1428 return -1;
1429 }
1430
7a946beb 1431 path_len = strlen(path);
3d071855 1432 while ((entry = readdir(dir))) {
7a946beb
MJ
1433 struct stat st;
1434 size_t name_len;
1435 char filename[PATH_MAX];
1436
3763af87
JG
1437 if (!strcmp(entry->d_name, ".")
1438 || !strcmp(entry->d_name, "..")) {
1439 continue;
1440 }
1441
7a946beb
MJ
1442 name_len = strlen(entry->d_name);
1443 if (path_len + name_len + 2 > sizeof(filename)) {
1444 ERR("Failed to remove file: path name too long (%s/%s)",
1445 path, entry->d_name);
1446 continue;
1447 }
1448 if (snprintf(filename, sizeof(filename), "%s/%s",
1449 path, entry->d_name) < 0) {
1450 ERR("Failed to format path.");
1451 continue;
1452 }
1453
1454 if (stat(filename, &st)) {
1455 PERROR("stat");
1456 continue;
1457 }
1458
1459 if (S_ISDIR(st.st_mode)) {
3d071855
MD
1460 char subpath[PATH_MAX];
1461
1462 strncpy(subpath, path, PATH_MAX);
1463 subpath[PATH_MAX - 1] = '\0';
1464 strncat(subpath, "/",
1465 PATH_MAX - strlen(subpath) - 1);
1466 strncat(subpath, entry->d_name,
1467 PATH_MAX - strlen(subpath) - 1);
9529ec1b
MD
1468 if (utils_recursive_rmdir(subpath)) {
1469 is_empty = 0;
3d071855 1470 }
7a946beb 1471 } else if (S_ISREG(st.st_mode)) {
9529ec1b 1472 is_empty = 0;
7a946beb 1473 } else {
3d071855
MD
1474 ret = -EINVAL;
1475 goto end;
1476 }
1477 }
1478end:
1479 closeret = closedir(dir);
1480 if (closeret) {
1481 PERROR("closedir");
1482 }
9529ec1b 1483 if (is_empty) {
3d071855
MD
1484 DBG3("Attempting rmdir %s", path);
1485 ret = rmdir(path);
1486 }
1487 return ret;
1488}
93ec662e
JD
1489
1490LTTNG_HIDDEN
1491int utils_truncate_stream_file(int fd, off_t length)
1492{
1493 int ret;
a5df8828 1494 off_t lseek_ret;
93ec662e
JD
1495
1496 ret = ftruncate(fd, length);
1497 if (ret < 0) {
1498 PERROR("ftruncate");
1499 goto end;
1500 }
a5df8828
GL
1501 lseek_ret = lseek(fd, length, SEEK_SET);
1502 if (lseek_ret < 0) {
93ec662e 1503 PERROR("lseek");
a5df8828 1504 ret = -1;
93ec662e
JD
1505 goto end;
1506 }
93ec662e
JD
1507end:
1508 return ret;
1509}
4ba92f18
PP
1510
1511static const char *get_man_bin_path(void)
1512{
b7dce40d 1513 char *env_man_path = lttng_secure_getenv(DEFAULT_MAN_BIN_PATH_ENV);
4ba92f18
PP
1514
1515 if (env_man_path) {
1516 return env_man_path;
1517 }
1518
1519 return DEFAULT_MAN_BIN_PATH;
1520}
1521
1522LTTNG_HIDDEN
4fc83d94
PP
1523int utils_show_help(int section, const char *page_name,
1524 const char *help_msg)
4ba92f18
PP
1525{
1526 char section_string[8];
1527 const char *man_bin_path = get_man_bin_path();
4fc83d94
PP
1528 int ret = 0;
1529
1530 if (help_msg) {
1531 printf("%s", help_msg);
1532 goto end;
1533 }
4ba92f18
PP
1534
1535 /* Section integer -> section string */
1536 ret = sprintf(section_string, "%d", section);
1537 assert(ret > 0 && ret < 8);
1538
1539 /*
1540 * Execute man pager.
1541 *
b07e7ef0 1542 * We provide -M to man here because LTTng-tools can
4ba92f18
PP
1543 * be installed outside /usr, in which case its man pages are
1544 * not located in the default /usr/share/man directory.
1545 */
b07e7ef0 1546 ret = execlp(man_bin_path, "man", "-M", MANPATH,
4ba92f18 1547 section_string, page_name, NULL);
4fc83d94
PP
1548
1549end:
4ba92f18
PP
1550 return ret;
1551}
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