1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
/* Atfork handling. Hurd pthread version.
Copyright (C) 2002-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdlib.h>
#include <libc-lock.h>
#include <fork.h>
struct atfork
{
void (*prepare) (void);
void (*parent) (void);
void (*child) (void);
void *dso_handle;
struct atfork *prev;
struct atfork *next;
};
/* TODO: better locking */
__libc_lock_define_initialized (static, atfork_lock);
static struct atfork *fork_handlers, *fork_last_handler;
static void
atfork_pthread_prepare (void)
{
struct atfork *handlers, *last_handler;
__libc_lock_lock (atfork_lock);
handlers = fork_handlers;
last_handler = fork_last_handler;
__libc_lock_unlock (atfork_lock);
if (last_handler == NULL)
return;
while (1)
{
if (last_handler->prepare != NULL)
last_handler->prepare ();
if (last_handler == handlers)
break;
last_handler = last_handler->prev;
}
}
text_set_element (_hurd_atfork_prepare_hook, atfork_pthread_prepare);
static void
atfork_pthread_parent (void)
{
struct atfork *handlers;
__libc_lock_lock (atfork_lock);
handlers = fork_handlers;
__libc_lock_unlock (atfork_lock);
while (handlers != NULL)
{
if (handlers->parent != NULL)
handlers->parent ();
handlers = handlers->next;
}
}
text_set_element (_hurd_atfork_parent_hook, atfork_pthread_parent);
static void
atfork_pthread_child (void)
{
struct atfork *handlers;
__libc_lock_lock (atfork_lock);
handlers = fork_handlers;
__libc_lock_unlock (atfork_lock);
while (handlers != NULL)
{
if (handlers->child != NULL)
handlers->child ();
handlers = handlers->next;
}
}
text_set_element (_hurd_atfork_child_hook, atfork_pthread_child);
int
__register_atfork (void (*prepare) (void),
void (*parent) (void),
void (*child) (void),
void *dso_handle)
{
struct atfork *new = malloc (sizeof (*new));
if (new == NULL)
return errno;
new->prepare = prepare;
new->parent = parent;
new->child = child;
new->dso_handle = dso_handle;
new->prev = NULL;
__libc_lock_lock (atfork_lock);
new->next = fork_handlers;
if (fork_handlers != NULL)
fork_handlers->prev = new;
fork_handlers = new;
if (fork_last_handler == NULL)
fork_last_handler = new;
__libc_lock_unlock (atfork_lock);
return 0;
}
libc_hidden_def (__register_atfork)
void
__unregister_atfork (void *dso_handle)
{
struct atfork **handlers, *prev = NULL, *next;
__libc_lock_lock (atfork_lock);
handlers = &fork_handlers;
while (*handlers != NULL)
{
if ((*handlers)->dso_handle == dso_handle)
{
/* Drop this handler from the list. */
if (*handlers == fork_last_handler)
{
/* Was last, new last is prev, if any. */
fork_last_handler = prev;
}
next = (*handlers)->next;
if (next != NULL)
next->prev = prev;
*handlers = next;
}
else
{
/* Just proceed to next handler. */
prev = *handlers;
handlers = &prev->next;
}
}
__libc_lock_unlock (atfork_lock);
}
|
