1 | //------------------------------------------------------------------------------ |
2 | // Copyright (c) 2016 by Lukasz Janyst <lukasz@jany.st> |
3 | //------------------------------------------------------------------------------ |
4 | // This file is part of thread-bites. |
5 | // |
6 | // thread-bites is free software: you can redistribute it and/or modify |
7 | // it under the terms of the GNU General Public License as published by |
8 | // the Free Software Foundation, either version 3 of the License, or |
9 | // (at your option) any later version. |
10 | // |
11 | // thread-bites is distributed in the hope that it will be useful, |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | // GNU General Public License for more details. |
15 | // |
16 | // You should have received a copy of the GNU General Public License |
17 | // along with thread-bites. If not, see <http://www.gnu.org/licenses/>. |
18 | //------------------------------------------------------------------------------ |
19 | |
20 | #include "tb.h" |
21 | |
22 | //------------------------------------------------------------------------------ |
23 | // Get the pointer of the currently running thread |
24 | //------------------------------------------------------------------------------ |
25 | tbthread_t tbthread_self() |
26 | { |
27 | tbthread_t self; |
28 | asm("movq %%fs:0, %0\n\t" : "=r" (self)); |
29 | return self; |
30 | } |
31 | |
32 | //------------------------------------------------------------------------------ |
33 | // The keys and helpers |
34 | //------------------------------------------------------------------------------ |
35 | static struct |
36 | { |
37 | uint64_t seq; |
38 | void (*destructor)(void *); |
39 | } keys[TBTHREAD_MAX_KEYS]; |
40 | |
41 | #define KEY_UNUSED(k) ((keys[k].seq&1) == 0) |
42 | #define KEY_ACQUIRE(k) (__sync_bool_compare_and_swap(&(keys[k].seq), keys[k].seq, keys[k].seq+1)) |
43 | #define KEY_RELEASE(k) (__sync_bool_compare_and_swap(&(keys[k].seq), keys[k].seq, keys[k].seq+1)) |
44 | |
45 | //------------------------------------------------------------------------------ |
46 | // Create a key |
47 | //------------------------------------------------------------------------------ |
48 | int tbthread_key_create(tbthread_key_t *key, void (*destructor)(void *)) |
49 | { |
50 | for(tbthread_key_t i = 0; i < TBTHREAD_MAX_KEYS; ++i) { |
51 | if(KEY_UNUSED(i) && KEY_ACQUIRE(i)) { |
52 | *key = i; |
53 | keys[i].destructor = destructor; |
54 | return 0; |
55 | } |
56 | } |
57 | return -ENOMEM; |
58 | } |
59 | |
60 | //------------------------------------------------------------------------------ |
61 | // Delete the key |
62 | //------------------------------------------------------------------------------ |
63 | int tbthread_key_delete(tbthread_key_t key) |
64 | { |
65 | if(key >= TBTHREAD_MAX_KEYS) |
66 | return -EINVAL; |
67 | |
68 | if(!KEY_UNUSED(key) && KEY_RELEASE(key)) |
69 | return 0; |
70 | |
71 | return -EINVAL; |
72 | } |
73 | |
74 | //------------------------------------------------------------------------------ |
75 | // Get the thread specific data associated with the key |
76 | //------------------------------------------------------------------------------ |
77 | void *tbthread_getspecific(tbthread_key_t key) |
78 | { |
79 | if(key >= TBTHREAD_MAX_KEYS || KEY_UNUSED(key)) |
80 | return 0; |
81 | |
82 | tbthread_t self = tbthread_self(); |
83 | if(self->tls[key].seq == keys[key].seq) |
84 | return self->tls[key].data; |
85 | return 0; |
86 | } |
87 | |
88 | //------------------------------------------------------------------------------ |
89 | // Associate thread specific data with the key |
90 | //------------------------------------------------------------------------------ |
91 | int tbthread_setspecific(tbthread_key_t key, void *value) |
92 | { |
93 | if(key >= TBTHREAD_MAX_KEYS || KEY_UNUSED(key)) |
94 | return -EINVAL; |
95 | |
96 | tbthread_t self = tbthread_self(); |
97 | self->tls[key].seq = keys[key].seq; |
98 | self->tls[key].data = value; |
99 | return 0; |
100 | } |
101 | |
102 | //------------------------------------------------------------------------------ |
103 | // Call the destructors of all the non-null values |
104 | //------------------------------------------------------------------------------ |
105 | void tb_tls_call_destructors() |
106 | { |
107 | tbthread_t self = tbthread_self(); |
108 | for(tbthread_key_t i = 0; i < TBTHREAD_MAX_KEYS; ++i) { |
109 | if(!KEY_UNUSED(i) && self->tls[i].seq == keys[i].seq && |
110 | self->tls[i].data && keys[i].destructor) { |
111 | void *data = self->tls[i].data; |
112 | self->tls[i].data = 0; |
113 | keys[i].destructor(data); |
114 | } |
115 | } |
116 | } |
117 | |