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2b778ceb | 1 | /* Copyright (C) 1999-2021 Free Software Foundation, Inc. |
c41041bc UD |
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 | |
41bdb6e2 AJ |
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. | |
c41041bc UD |
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 | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
c41041bc | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
c41041bc | 17 | |
b6caa3a6 | 18 | #include <assert.h> |
a334319f | 19 | #include <stdlib.h> |
e054f494 | 20 | #include <stdint.h> |
b6caa3a6 | 21 | |
ec999b8e | 22 | #include <libc-lock.h> |
c41041bc | 23 | #include "exit.h" |
a3c88553 | 24 | #include <sysdep.h> |
c41041bc | 25 | |
6b87a564 UD |
26 | #undef __cxa_atexit |
27 | ||
26e70aec PP |
28 | /* See concurrency notes in stdlib/exit.h where this lock is declared. */ |
29 | __libc_lock_define_initialized (, __exit_funcs_lock) | |
30 | ||
610e67ed | 31 | |
c41041bc | 32 | int |
610e67ed UD |
33 | attribute_hidden |
34 | __internal_atexit (void (*func) (void *), void *arg, void *d, | |
35 | struct exit_function_list **listp) | |
c41041bc | 36 | { |
26e70aec PP |
37 | struct exit_function *new; |
38 | ||
8e67b39e PP |
39 | /* As a QoI issue we detect NULL early with an assertion instead |
40 | of a SIGSEGV at program exit when the handler is run (bug 20544). */ | |
41 | assert (func != NULL); | |
42 | ||
26e70aec PP |
43 | __libc_lock_lock (__exit_funcs_lock); |
44 | new = __new_exitfn (listp); | |
c41041bc UD |
45 | |
46 | if (new == NULL) | |
26e70aec PP |
47 | { |
48 | __libc_lock_unlock (__exit_funcs_lock); | |
49 | return -1; | |
50 | } | |
c41041bc | 51 | |
a3c88553 UD |
52 | #ifdef PTR_MANGLE |
53 | PTR_MANGLE (func); | |
54 | #endif | |
5ef50d00 | 55 | new->func.cxa.fn = (void (*) (void *, int)) func; |
c41041bc UD |
56 | new->func.cxa.arg = arg; |
57 | new->func.cxa.dso_handle = d; | |
a3c88553 | 58 | new->flavor = ef_cxa; |
26e70aec | 59 | __libc_lock_unlock (__exit_funcs_lock); |
c41041bc UD |
60 | return 0; |
61 | } | |
610e67ed UD |
62 | |
63 | ||
64 | /* Register a function to be called by exit or when a shared library | |
65 | is unloaded. This function is only called from code generated by | |
66 | the C++ compiler. */ | |
67 | int | |
68 | __cxa_atexit (void (*func) (void *), void *arg, void *d) | |
69 | { | |
70 | return __internal_atexit (func, arg, d, &__exit_funcs); | |
71 | } | |
cb831245 | 72 | libc_hidden_def (__cxa_atexit) |
c08bc50a UD |
73 | |
74 | ||
c08bc50a UD |
75 | static struct exit_function_list initial; |
76 | struct exit_function_list *__exit_funcs = &initial; | |
a92b1166 | 77 | uint64_t __new_exitfn_called; |
c08bc50a | 78 | |
26e70aec | 79 | /* Must be called with __exit_funcs_lock held. */ |
c08bc50a | 80 | struct exit_function * |
610e67ed | 81 | __new_exitfn (struct exit_function_list **listp) |
c08bc50a | 82 | { |
b6caa3a6 | 83 | struct exit_function_list *p = NULL; |
c08bc50a | 84 | struct exit_function_list *l; |
b6caa3a6 | 85 | struct exit_function *r = NULL; |
c08bc50a UD |
86 | size_t i = 0; |
87 | ||
26e70aec PP |
88 | if (__exit_funcs_done) |
89 | /* Exit code is finished processing all registered exit functions, | |
90 | therefore we fail this registration. */ | |
91 | return NULL; | |
c08bc50a | 92 | |
610e67ed | 93 | for (l = *listp; l != NULL; p = l, l = l->next) |
c08bc50a | 94 | { |
b6caa3a6 UD |
95 | for (i = l->idx; i > 0; --i) |
96 | if (l->fns[i - 1].flavor != ef_free) | |
c08bc50a | 97 | break; |
b6caa3a6 UD |
98 | |
99 | if (i > 0) | |
c08bc50a UD |
100 | break; |
101 | ||
b6caa3a6 UD |
102 | /* This block is completely unused. */ |
103 | l->idx = 0; | |
c08bc50a UD |
104 | } |
105 | ||
b6caa3a6 | 106 | if (l == NULL || i == sizeof (l->fns) / sizeof (l->fns[0])) |
c08bc50a | 107 | { |
b6caa3a6 UD |
108 | /* The last entry in a block is used. Use the first entry in |
109 | the previous block if it exists. Otherwise create a new one. */ | |
110 | if (p == NULL) | |
c08bc50a | 111 | { |
b6caa3a6 UD |
112 | assert (l != NULL); |
113 | p = (struct exit_function_list *) | |
114 | calloc (1, sizeof (struct exit_function_list)); | |
115 | if (p != NULL) | |
116 | { | |
610e67ed UD |
117 | p->next = *listp; |
118 | *listp = p; | |
b6caa3a6 UD |
119 | } |
120 | } | |
c08bc50a | 121 | |
b6caa3a6 UD |
122 | if (p != NULL) |
123 | { | |
124 | r = &p->fns[0]; | |
125 | p->idx = 1; | |
c08bc50a UD |
126 | } |
127 | } | |
b6caa3a6 UD |
128 | else |
129 | { | |
130 | /* There is more room in the block. */ | |
131 | r = &l->fns[i]; | |
132 | l->idx = i + 1; | |
133 | } | |
c08bc50a UD |
134 | |
135 | /* Mark entry as used, but we don't know the flavor now. */ | |
b6caa3a6 | 136 | if (r != NULL) |
a92b1166 UD |
137 | { |
138 | r->flavor = ef_us; | |
139 | ++__new_exitfn_called; | |
140 | } | |
c08bc50a | 141 | |
b6caa3a6 | 142 | return r; |
c08bc50a | 143 | } |