1/* pthread_key_create. Hurd version.
2 Copyright (C) 2002-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <pthread.h>
20#include <stdlib.h>
21#include <assert.h>
22
23#include <pt-internal.h>
24#include <pthreadP.h>
25
26pthread_mutex_t __pthread_key_lock;
27
28void (**__pthread_key_destructors) (void *arg);
29int __pthread_key_size;
30int __pthread_key_count;
31int __pthread_key_invalid_count;
32
33int
34__pthread_key_create (pthread_key_t *key, void (*destructor) (void *))
35{
36 /* Where to look for the next key slot. */
37 static int index;
38
39 __pthread_key_lock_ready ();
40
41 __pthread_mutex_lock (&__pthread_key_lock);
42
43do_search:
44 /* Use the search hint and try to find a free slot. */
45 for (; index < __pthread_key_count
46 && __pthread_key_destructors[index] != PTHREAD_KEY_INVALID; index++)
47 ;
48
49 /* See if we actually found a free element. */
50 if (index < __pthread_key_count)
51 {
52 assert (__pthread_key_destructors[index] == PTHREAD_KEY_INVALID);
53 assert (__pthread_key_invalid_count > 0);
54
55 __pthread_key_invalid_count--;
56 __pthread_key_destructors[index] = destructor;
57 *key = index++;
58
59 __pthread_mutex_unlock (&__pthread_key_lock);
60 return 0;
61 }
62
63 assert (index == __pthread_key_count);
64
65 /* No space at the end. */
66 if (__pthread_key_size == __pthread_key_count)
67 {
68 /* See if it is worth looking for a free element. */
69 if (__pthread_key_invalid_count > 4
70 && __pthread_key_invalid_count > __pthread_key_size / 8)
71 {
72 index = 0;
73 goto do_search;
74 }
75
76
77 /* Resize the array. */
78 {
79 void *t;
80 int newsize;
81
82 if (__pthread_key_size == 0)
83 newsize = 8;
84 else
85 newsize = __pthread_key_size * 2;
86
87 t = realloc (ptr: __pthread_key_destructors,
88 size: newsize * sizeof (*__pthread_key_destructors));
89 if (t == NULL)
90 {
91 __pthread_mutex_unlock (&__pthread_key_lock);
92 return ENOMEM;
93 }
94
95 __pthread_key_size = newsize;
96 __pthread_key_destructors = t;
97 }
98 }
99
100 __pthread_key_destructors[index] = destructor;
101 *key = index;
102
103 index++;
104 __pthread_key_count++;
105
106 __pthread_mutex_unlock (&__pthread_key_lock);
107 return 0;
108}
109weak_alias (__pthread_key_create, pthread_key_create)
110hidden_def (__pthread_key_create)
111

source code of glibc/sysdeps/htl/pt-key-create.c