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2b778ceb | 1 | /* Copyright (C) 2002-2021 Free Software Foundation, Inc. |
76a50749 UD |
2 | This file is part of the GNU C Library. |
3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
76a50749 | 18 | |
68a396e8 UD |
19 | #include <errno.h> |
20 | #include <search.h> | |
76a50749 | 21 | #include <sys/mman.h> |
68a396e8 UD |
22 | #include "semaphoreP.h" |
23 | ||
4aee85f9 FW |
24 | struct walk_closure |
25 | { | |
26 | sem_t *the_sem; | |
27 | struct inuse_sem *rec; | |
28 | }; | |
68a396e8 UD |
29 | |
30 | static void | |
4aee85f9 | 31 | walker (const void *inodep, VISIT which, void *closure0) |
68a396e8 | 32 | { |
4aee85f9 | 33 | struct walk_closure *closure = closure0; |
68a396e8 UD |
34 | struct inuse_sem *nodep = *(struct inuse_sem **) inodep; |
35 | ||
4aee85f9 FW |
36 | if (nodep->sem == closure->the_sem) |
37 | closure->rec = nodep; | |
68a396e8 | 38 | } |
76a50749 UD |
39 | |
40 | ||
41 | int | |
9d46370c | 42 | sem_close (sem_t *sem) |
76a50749 | 43 | { |
68a396e8 UD |
44 | int result = 0; |
45 | ||
46 | /* Get the lock. */ | |
e51deae7 | 47 | lll_lock (__sem_mappings_lock, LLL_PRIVATE); |
68a396e8 UD |
48 | |
49 | /* Locate the entry for the mapping the caller provided. */ | |
4aee85f9 FW |
50 | struct inuse_sem *rec; |
51 | { | |
52 | struct walk_closure closure = { .the_sem = sem, .rec = NULL }; | |
53 | __twalk_r (__sem_mappings, walker, &closure); | |
54 | rec = closure.rec; | |
55 | } | |
68a396e8 UD |
56 | if (rec != NULL) |
57 | { | |
58 | /* Check the reference counter. If it is going to be zero, free | |
59 | all the resources. */ | |
60 | if (--rec->refcnt == 0) | |
61 | { | |
62 | /* Remove the record from the tree. */ | |
d051b143 | 63 | (void) __tdelete (rec, &__sem_mappings, __sem_search); |
68a396e8 UD |
64 | |
65 | result = munmap (rec->sem, sizeof (sem_t)); | |
66 | ||
67 | free (rec); | |
68 | } | |
69 | } | |
70 | else | |
71 | { | |
72 | /* This is no valid semaphore. */ | |
73 | result = -1; | |
74 | __set_errno (EINVAL); | |
75 | } | |
76 | ||
77 | /* Release the lock. */ | |
e51deae7 | 78 | lll_unlock (__sem_mappings_lock, LLL_PRIVATE); |
68a396e8 UD |
79 | |
80 | return result; | |
76a50749 | 81 | } |