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68a396e8 | 1 | /* Copyright (C) 2002, 2003 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 | |
16 | License along with the GNU C Library; if not, write to the Free | |
17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
18 | 02111-1307 USA. */ | |
19 | ||
68a396e8 UD |
20 | #include <errno.h> |
21 | #include <search.h> | |
76a50749 | 22 | #include <sys/mman.h> |
68a396e8 UD |
23 | #include "semaphoreP.h" |
24 | ||
25 | ||
26 | /* Global variables to parametrize the walk function. This works | |
27 | since we always have to use locks. And we have to use the twalk | |
28 | function since the entries are not sorted wrt the mapping | |
29 | address. */ | |
30 | static sem_t *the_sem; | |
31 | static struct inuse_sem *rec; | |
32 | ||
33 | static void | |
34 | walker (const void *inodep, const VISIT which, const int depth) | |
35 | { | |
36 | struct inuse_sem *nodep = *(struct inuse_sem **) inodep; | |
37 | ||
38 | if (nodep->sem == the_sem) | |
39 | rec = nodep; | |
40 | } | |
76a50749 UD |
41 | |
42 | ||
43 | int | |
44 | sem_close (sem) | |
45 | sem_t *sem; | |
46 | { | |
68a396e8 UD |
47 | int result = 0; |
48 | ||
49 | /* Get the lock. */ | |
50 | lll_lock (__sem_mappings_lock); | |
51 | ||
52 | /* Locate the entry for the mapping the caller provided. */ | |
53 | rec = NULL; | |
54 | the_sem = sem; | |
55 | twalk (__sem_mappings, walker); | |
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. */ | |
63 | (void) tdelete (rec, &__sem_mappings, __sem_search); | |
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. */ | |
78 | lll_unlock (__sem_mappings_lock); | |
79 | ||
80 | return result; | |
76a50749 | 81 | } |