Implement poll mask modification support in poll wrappers
[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);
531 ret = -1;
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 {
7591bab1
MD
758 strncpy(path, full_path, PATH_MAX - 1);
759 }
760 path[PATH_MAX - 1] = '\0';
761 ret = 0;
762
763 free(path_name_suffix);
764error_free_suffix:
765 free(extra);
766error:
767 return ret;
768}
769
770/*
771 * Create the stream file on disk.
772 *
773 * Return 0 on success or else a negative value.
774 */
775LTTNG_HIDDEN
776int utils_create_stream_file(const char *path_name, char *file_name, uint64_t size,
777 uint64_t count, int uid, int gid, char *suffix)
778{
779 int ret, flags, mode;
780 char path[PATH_MAX];
781
782 ret = utils_stream_file_name(path, path_name, file_name,
783 size, count, suffix);
784 if (ret < 0) {
785 goto error;
fe4477ee
JD
786 }
787
be96a7d1 788 flags = O_WRONLY | O_CREAT | O_TRUNC;
0f907de1 789 /* Open with 660 mode */
be96a7d1
DG
790 mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
791
792 if (uid < 0 || gid < 0) {
7591bab1 793 ret = open(path, flags, mode);
be96a7d1 794 } else {
7591bab1 795 ret = run_as_open(path, flags, mode, uid, gid);
be96a7d1 796 }
7591bab1 797 if (ret < 0) {
fe4477ee 798 PERROR("open stream path %s", path);
fe4477ee 799 }
7591bab1
MD
800error:
801 return ret;
802}
fe4477ee 803
7591bab1
MD
804/*
805 * Unlink the stream tracefile from disk.
806 *
807 * Return 0 on success or else a negative value.
808 */
809LTTNG_HIDDEN
810int utils_unlink_stream_file(const char *path_name, char *file_name, uint64_t size,
811 uint64_t count, int uid, int gid, char *suffix)
812{
813 int ret;
814 char path[PATH_MAX];
815
816 ret = utils_stream_file_name(path, path_name, file_name,
817 size, count, suffix);
818 if (ret < 0) {
819 goto error;
820 }
821 if (uid < 0 || gid < 0) {
822 ret = unlink(path);
823 } else {
824 ret = run_as_unlink(path, uid, gid);
7591bab1
MD
825 }
826 if (ret < 0) {
827 goto error;
828 }
fe4477ee 829error:
7591bab1 830 DBG("utils_unlink_stream_file %s returns %d", path, ret);
fe4477ee
JD
831 return ret;
832}
833
834/*
835 * Change the output tracefile according to the given size and count The
836 * new_count pointer is set during this operation.
837 *
838 * From the consumer, the stream lock MUST be held before calling this function
839 * because we are modifying the stream status.
840 *
841 * Return 0 on success or else a negative value.
842 */
bc182241 843LTTNG_HIDDEN
fe4477ee 844int utils_rotate_stream_file(char *path_name, char *file_name, uint64_t size,
309167d2
JD
845 uint64_t count, int uid, int gid, int out_fd, uint64_t *new_count,
846 int *stream_fd)
fe4477ee
JD
847{
848 int ret;
849
309167d2
JD
850 assert(stream_fd);
851
fe4477ee
JD
852 ret = close(out_fd);
853 if (ret < 0) {
854 PERROR("Closing tracefile");
855 goto error;
856 }
b5b0c181 857 *stream_fd = -1;
fe4477ee
JD
858
859 if (count > 0) {
7591bab1
MD
860 /*
861 * In tracefile rotation, for the relay daemon we need
862 * to unlink the old file if present, because it may
863 * still be open in reading by the live thread, and we
864 * need to ensure that we do not overwrite the content
865 * between get_index and get_packet. Since we have no
866 * way to verify integrity of the data content compared
867 * to the associated index, we need to ensure the reader
868 * has exclusive access to the file content, and that
869 * the open of the data file is performed in get_index.
870 * Unlinking the old file rather than overwriting it
871 * achieves this.
872 */
93ec662e
JD
873 if (new_count) {
874 *new_count = (*new_count + 1) % count;
875 }
876 ret = utils_unlink_stream_file(path_name, file_name, size,
877 new_count ? *new_count : 0, uid, gid, 0);
7591bab1
MD
878 if (ret < 0 && errno != ENOENT) {
879 goto error;
880 }
fe4477ee 881 } else {
93ec662e
JD
882 if (new_count) {
883 (*new_count)++;
884 }
fe4477ee
JD
885 }
886
93ec662e
JD
887 ret = utils_create_stream_file(path_name, file_name, size,
888 new_count ? *new_count : 0, uid, gid, 0);
309167d2
JD
889 if (ret < 0) {
890 goto error;
891 }
892 *stream_fd = ret;
893
894 /* Success. */
895 ret = 0;
896
fe4477ee
JD
897error:
898 return ret;
899}
70d0b120 900
70d0b120
SM
901
902/**
903 * Parse a string that represents a size in human readable format. It
5983a922 904 * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
70d0b120
SM
905 *
906 * The suffix multiply the integer by:
907 * 'k': 1024
908 * 'M': 1024^2
909 * 'G': 1024^3
910 *
911 * @param str The string to parse.
5983a922 912 * @param size Pointer to a uint64_t that will be filled with the
cfa9a5a2 913 * resulting size.
70d0b120
SM
914 *
915 * @return 0 on success, -1 on failure.
916 */
00a52467 917LTTNG_HIDDEN
5983a922 918int utils_parse_size_suffix(const char * const str, uint64_t * const size)
70d0b120 919{
70d0b120 920 int ret;
5983a922 921 uint64_t base_size;
70d0b120 922 long shift = 0;
5983a922
SM
923 const char *str_end;
924 char *num_end;
70d0b120
SM
925
926 if (!str) {
5983a922 927 DBG("utils_parse_size_suffix: received a NULL string.");
70d0b120
SM
928 ret = -1;
929 goto end;
930 }
931
5983a922
SM
932 /* strtoull will accept a negative number, but we don't want to. */
933 if (strchr(str, '-') != NULL) {
934 DBG("utils_parse_size_suffix: invalid size string, should not contain '-'.");
70d0b120 935 ret = -1;
5983a922 936 goto end;
70d0b120
SM
937 }
938
5983a922
SM
939 /* str_end will point to the \0 */
940 str_end = str + strlen(str);
70d0b120 941 errno = 0;
5983a922 942 base_size = strtoull(str, &num_end, 0);
70d0b120 943 if (errno != 0) {
5983a922 944 PERROR("utils_parse_size_suffix strtoull");
70d0b120 945 ret = -1;
5983a922
SM
946 goto end;
947 }
948
949 if (num_end == str) {
950 /* strtoull parsed nothing, not good. */
951 DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
952 ret = -1;
953 goto end;
954 }
955
956 /* Check if a prefix is present. */
957 switch (*num_end) {
958 case 'G':
959 shift = GIBI_LOG2;
960 num_end++;
961 break;
962 case 'M': /* */
963 shift = MEBI_LOG2;
964 num_end++;
965 break;
966 case 'K':
967 case 'k':
968 shift = KIBI_LOG2;
969 num_end++;
970 break;
971 case '\0':
972 break;
973 default:
974 DBG("utils_parse_size_suffix: invalid suffix.");
975 ret = -1;
976 goto end;
977 }
978
979 /* Check for garbage after the valid input. */
980 if (num_end != str_end) {
981 DBG("utils_parse_size_suffix: Garbage after size string.");
982 ret = -1;
983 goto end;
70d0b120
SM
984 }
985
986 *size = base_size << shift;
987
988 /* Check for overflow */
989 if ((*size >> shift) != base_size) {
5983a922 990 DBG("utils_parse_size_suffix: oops, overflow detected.");
70d0b120 991 ret = -1;
5983a922 992 goto end;
70d0b120
SM
993 }
994
995 ret = 0;
70d0b120
SM
996end:
997 return ret;
998}
cfa9a5a2
DG
999
1000/*
1001 * fls: returns the position of the most significant bit.
1002 * Returns 0 if no bit is set, else returns the position of the most
1003 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
1004 */
1005#if defined(__i386) || defined(__x86_64)
1006static inline unsigned int fls_u32(uint32_t x)
1007{
1008 int r;
1009
1010 asm("bsrl %1,%0\n\t"
1011 "jnz 1f\n\t"
1012 "movl $-1,%0\n\t"
1013 "1:\n\t"
1014 : "=r" (r) : "rm" (x));
1015 return r + 1;
1016}
1017#define HAS_FLS_U32
1018#endif
1019
1020#ifndef HAS_FLS_U32
1021static __attribute__((unused)) unsigned int fls_u32(uint32_t x)
1022{
1023 unsigned int r = 32;
1024
1025 if (!x) {
1026 return 0;
1027 }
1028 if (!(x & 0xFFFF0000U)) {
1029 x <<= 16;
1030 r -= 16;
1031 }
1032 if (!(x & 0xFF000000U)) {
1033 x <<= 8;
1034 r -= 8;
1035 }
1036 if (!(x & 0xF0000000U)) {
1037 x <<= 4;
1038 r -= 4;
1039 }
1040 if (!(x & 0xC0000000U)) {
1041 x <<= 2;
1042 r -= 2;
1043 }
1044 if (!(x & 0x80000000U)) {
1045 x <<= 1;
1046 r -= 1;
1047 }
1048 return r;
1049}
1050#endif
1051
1052/*
1053 * Return the minimum order for which x <= (1UL << order).
1054 * Return -1 if x is 0.
1055 */
1056LTTNG_HIDDEN
1057int utils_get_count_order_u32(uint32_t x)
1058{
1059 if (!x) {
1060 return -1;
1061 }
1062
1063 return fls_u32(x - 1);
1064}
feb0f3e5
AM
1065
1066/**
1067 * Obtain the value of LTTNG_HOME environment variable, if exists.
1068 * Otherwise returns the value of HOME.
1069 */
00a52467 1070LTTNG_HIDDEN
feb0f3e5
AM
1071char *utils_get_home_dir(void)
1072{
1073 char *val = NULL;
04135dbd
DG
1074 struct passwd *pwd;
1075
e8fa9fb0 1076 val = lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
feb0f3e5 1077 if (val != NULL) {
04135dbd
DG
1078 goto end;
1079 }
e8fa9fb0 1080 val = lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
04135dbd
DG
1081 if (val != NULL) {
1082 goto end;
feb0f3e5 1083 }
04135dbd
DG
1084
1085 /* Fallback on the password file entry. */
1086 pwd = getpwuid(getuid());
1087 if (!pwd) {
1088 goto end;
1089 }
1090 val = pwd->pw_dir;
1091
1092 DBG3("Home directory is '%s'", val);
1093
1094end:
1095 return val;
feb0f3e5 1096}
26fe5938 1097
fb198a11
JG
1098/**
1099 * Get user's home directory. Dynamically allocated, must be freed
1100 * by the caller.
1101 */
1102LTTNG_HIDDEN
1103char *utils_get_user_home_dir(uid_t uid)
1104{
1105 struct passwd pwd;
1106 struct passwd *result;
1107 char *home_dir = NULL;
1108 char *buf = NULL;
1109 long buflen;
1110 int ret;
1111
1112 buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
1113 if (buflen == -1) {
1114 goto end;
1115 }
1116retry:
1117 buf = zmalloc(buflen);
1118 if (!buf) {
1119 goto end;
1120 }
1121
1122 ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
1123 if (ret || !result) {
1124 if (ret == ERANGE) {
1125 free(buf);
1126 buflen *= 2;
1127 goto retry;
1128 }
1129 goto end;
1130 }
1131
1132 home_dir = strdup(pwd.pw_dir);
1133end:
1134 free(buf);
1135 return home_dir;
1136}
1137
fbb9748b
JG
1138/*
1139 * Obtain the value of LTTNG_KMOD_PROBES environment variable, if exists.
c9d42407 1140 * Otherwise returns NULL.
fbb9748b
JG
1141 */
1142LTTNG_HIDDEN
1143char *utils_get_kmod_probes_list(void)
1144{
e8fa9fb0 1145 return lttng_secure_getenv(DEFAULT_LTTNG_KMOD_PROBES);
fbb9748b
JG
1146}
1147
c9d42407
PP
1148/*
1149 * Obtain the value of LTTNG_EXTRA_KMOD_PROBES environment variable, if
1150 * exists. Otherwise returns NULL.
1151 */
1152LTTNG_HIDDEN
1153char *utils_get_extra_kmod_probes_list(void)
1154{
e8fa9fb0 1155 return lttng_secure_getenv(DEFAULT_LTTNG_EXTRA_KMOD_PROBES);
c9d42407
PP
1156}
1157
26fe5938
DG
1158/*
1159 * With the given format, fill dst with the time of len maximum siz.
1160 *
1161 * Return amount of bytes set in the buffer or else 0 on error.
1162 */
1163LTTNG_HIDDEN
1164size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
1165{
1166 size_t ret;
1167 time_t rawtime;
1168 struct tm *timeinfo;
1169
1170 assert(format);
1171 assert(dst);
1172
1173 /* Get date and time for session path */
1174 time(&rawtime);
1175 timeinfo = localtime(&rawtime);
1176 ret = strftime(dst, len, format, timeinfo);
1177 if (ret == 0) {
68e6efdd 1178 ERR("Unable to strftime with format %s at dst %p of len %zu", format,
26fe5938
DG
1179 dst, len);
1180 }
1181
1182 return ret;
1183}
6c71277b
MD
1184
1185/*
1186 * Return the group ID matching name, else 0 if it cannot be found.
1187 */
1188LTTNG_HIDDEN
1189gid_t utils_get_group_id(const char *name)
1190{
1191 struct group *grp;
1192
1193 grp = getgrnam(name);
1194 if (!grp) {
1195 static volatile int warn_once;
1196
1197 if (!warn_once) {
1198 WARN("No tracing group detected");
1199 warn_once = 1;
1200 }
1201 return 0;
1202 }
1203 return grp->gr_gid;
1204}
8db0dc00
JG
1205
1206/*
1207 * Return a newly allocated option string. This string is to be used as the
1208 * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
1209 * of elements in the long_options array. Returns NULL if the string's
1210 * allocation fails.
1211 */
1212LTTNG_HIDDEN
1213char *utils_generate_optstring(const struct option *long_options,
1214 size_t opt_count)
1215{
1216 int i;
1217 size_t string_len = opt_count, str_pos = 0;
1218 char *optstring;
1219
1220 /*
1221 * Compute the necessary string length. One letter per option, two when an
1222 * argument is necessary, and a trailing NULL.
1223 */
1224 for (i = 0; i < opt_count; i++) {
1225 string_len += long_options[i].has_arg ? 1 : 0;
1226 }
1227
1228 optstring = zmalloc(string_len);
1229 if (!optstring) {
1230 goto end;
1231 }
1232
1233 for (i = 0; i < opt_count; i++) {
1234 if (!long_options[i].name) {
1235 /* Got to the trailing NULL element */
1236 break;
1237 }
1238
a596dcb9
JG
1239 if (long_options[i].val != '\0') {
1240 optstring[str_pos++] = (char) long_options[i].val;
1241 if (long_options[i].has_arg) {
1242 optstring[str_pos++] = ':';
1243 }
8db0dc00
JG
1244 }
1245 }
1246
1247end:
1248 return optstring;
1249}
3d071855
MD
1250
1251/*
1252 * Try to remove a hierarchy of empty directories, recursively. Don't unlink
9529ec1b 1253 * any file. Try to rmdir any empty directory within the hierarchy.
3d071855
MD
1254 */
1255LTTNG_HIDDEN
1256int utils_recursive_rmdir(const char *path)
1257{
1258 DIR *dir;
7a946beb 1259 size_t path_len;
9529ec1b 1260 int dir_fd, ret = 0, closeret, is_empty = 1;
3d071855
MD
1261 struct dirent *entry;
1262
1263 /* Open directory */
1264 dir = opendir(path);
1265 if (!dir) {
1266 PERROR("Cannot open '%s' path", path);
1267 return -1;
1268 }
5a2451c9 1269 dir_fd = lttng_dirfd(dir);
3d071855 1270 if (dir_fd < 0) {
5a2451c9 1271 PERROR("lttng_dirfd");
3d071855
MD
1272 return -1;
1273 }
1274
7a946beb 1275 path_len = strlen(path);
3d071855 1276 while ((entry = readdir(dir))) {
7a946beb
MJ
1277 struct stat st;
1278 size_t name_len;
1279 char filename[PATH_MAX];
1280
3763af87
JG
1281 if (!strcmp(entry->d_name, ".")
1282 || !strcmp(entry->d_name, "..")) {
1283 continue;
1284 }
1285
7a946beb
MJ
1286 name_len = strlen(entry->d_name);
1287 if (path_len + name_len + 2 > sizeof(filename)) {
1288 ERR("Failed to remove file: path name too long (%s/%s)",
1289 path, entry->d_name);
1290 continue;
1291 }
1292 if (snprintf(filename, sizeof(filename), "%s/%s",
1293 path, entry->d_name) < 0) {
1294 ERR("Failed to format path.");
1295 continue;
1296 }
1297
1298 if (stat(filename, &st)) {
1299 PERROR("stat");
1300 continue;
1301 }
1302
1303 if (S_ISDIR(st.st_mode)) {
3d071855
MD
1304 char subpath[PATH_MAX];
1305
1306 strncpy(subpath, path, PATH_MAX);
1307 subpath[PATH_MAX - 1] = '\0';
1308 strncat(subpath, "/",
1309 PATH_MAX - strlen(subpath) - 1);
1310 strncat(subpath, entry->d_name,
1311 PATH_MAX - strlen(subpath) - 1);
9529ec1b
MD
1312 if (utils_recursive_rmdir(subpath)) {
1313 is_empty = 0;
3d071855 1314 }
7a946beb 1315 } else if (S_ISREG(st.st_mode)) {
9529ec1b 1316 is_empty = 0;
7a946beb 1317 } else {
3d071855
MD
1318 ret = -EINVAL;
1319 goto end;
1320 }
1321 }
1322end:
1323 closeret = closedir(dir);
1324 if (closeret) {
1325 PERROR("closedir");
1326 }
9529ec1b 1327 if (is_empty) {
3d071855
MD
1328 DBG3("Attempting rmdir %s", path);
1329 ret = rmdir(path);
1330 }
1331 return ret;
1332}
93ec662e
JD
1333
1334LTTNG_HIDDEN
1335int utils_truncate_stream_file(int fd, off_t length)
1336{
1337 int ret;
1338
1339 ret = ftruncate(fd, length);
1340 if (ret < 0) {
1341 PERROR("ftruncate");
1342 goto end;
1343 }
1344 ret = lseek(fd, length, SEEK_SET);
1345 if (ret < 0) {
1346 PERROR("lseek");
1347 goto end;
1348 }
93ec662e
JD
1349end:
1350 return ret;
1351}
4ba92f18
PP
1352
1353static const char *get_man_bin_path(void)
1354{
b7dce40d 1355 char *env_man_path = lttng_secure_getenv(DEFAULT_MAN_BIN_PATH_ENV);
4ba92f18
PP
1356
1357 if (env_man_path) {
1358 return env_man_path;
1359 }
1360
1361 return DEFAULT_MAN_BIN_PATH;
1362}
1363
1364LTTNG_HIDDEN
1365int utils_show_man_page(int section, const char *page_name)
1366{
1367 char section_string[8];
1368 const char *man_bin_path = get_man_bin_path();
1369 int ret;
1370
1371 /* Section integer -> section string */
1372 ret = sprintf(section_string, "%d", section);
1373 assert(ret > 0 && ret < 8);
1374
1375 /*
1376 * Execute man pager.
1377 *
b07e7ef0 1378 * We provide -M to man here because LTTng-tools can
4ba92f18
PP
1379 * be installed outside /usr, in which case its man pages are
1380 * not located in the default /usr/share/man directory.
1381 */
b07e7ef0 1382 ret = execlp(man_bin_path, "man", "-M", MANPATH,
4ba92f18
PP
1383 section_string, page_name, NULL);
1384 return ret;
1385}
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