1/* Deallocation thread-specific data structures related to pthread_key_create.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <pthreadP.h>
19
20/* Deallocate POSIX thread-local-storage. */
21void
22__nptl_deallocate_tsd (void)
23{
24 struct pthread *self = THREAD_SELF;
25
26 /* Maybe no data was ever allocated. This happens often so we have
27 a flag for this. */
28 if (THREAD_GETMEM (self, specific_used))
29 {
30 size_t round;
31 size_t cnt;
32
33 round = 0;
34 do
35 {
36 size_t idx;
37
38 /* So far no new nonzero data entry. */
39 THREAD_SETMEM (self, specific_used, false);
40
41 for (cnt = idx = 0; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
42 {
43 struct pthread_key_data *level2;
44
45 level2 = THREAD_GETMEM_NC (self, specific, cnt);
46
47 if (level2 != NULL)
48 {
49 size_t inner;
50
51 for (inner = 0; inner < PTHREAD_KEY_2NDLEVEL_SIZE;
52 ++inner, ++idx)
53 {
54 void *data = level2[inner].data;
55
56 if (data != NULL)
57 {
58 /* Always clear the data. */
59 level2[inner].data = NULL;
60
61 /* Make sure the data corresponds to a valid
62 key. This test fails if the key was
63 deallocated and also if it was
64 re-allocated. It is the user's
65 responsibility to free the memory in this
66 case. */
67 if (level2[inner].seq
68 == __pthread_keys[idx].seq
69 /* It is not necessary to register a destructor
70 function. */
71 && __pthread_keys[idx].destr != NULL)
72 /* Call the user-provided destructor. */
73 __pthread_keys[idx].destr (data);
74 }
75 }
76 }
77 else
78 idx += PTHREAD_KEY_1STLEVEL_SIZE;
79 }
80
81 if (THREAD_GETMEM (self, specific_used) == 0)
82 /* No data has been modified. */
83 goto just_free;
84 }
85 /* We only repeat the process a fixed number of times. */
86 while (__builtin_expect (++round < PTHREAD_DESTRUCTOR_ITERATIONS, 0));
87
88 /* Just clear the memory of the first block for reuse. */
89 memset (&THREAD_SELF->specific_1stblock, '\0',
90 sizeof (self->specific_1stblock));
91
92 just_free:
93 /* Free the memory for the other blocks. */
94 for (cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
95 {
96 struct pthread_key_data *level2;
97
98 level2 = THREAD_GETMEM_NC (self, specific, cnt);
99 if (level2 != NULL)
100 {
101 /* The first block is allocated as part of the thread
102 descriptor. */
103 free (level2);
104 THREAD_SETMEM_NC (self, specific, cnt, NULL);
105 }
106 }
107
108 THREAD_SETMEM (self, specific_used, false);
109 }
110}
111libc_hidden_def (__nptl_deallocate_tsd)
112