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
|
/* Copyright (C) 2001-2023 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 <netdb.h>
#include <pthread.h>
#include <stdlib.h>
#include <gai_misc.h>
#if !PTHREAD_IN_LIBC
/* The available function names differ outside of libc. (In libc, we
need to use hidden aliases to avoid the PLT.) */
#define __pthread_attr_init pthread_attr_init
#define __pthread_attr_setdetachstate pthread_attr_setdetachstate
#define __pthread_cond_signal pthread_cond_signal
#define __pthread_cond_timedwait pthread_cond_timedwait
#define __pthread_create pthread_create
#endif
struct notify_func
{
void (*func) (sigval_t);
sigval_t value;
};
static void *
notify_func_wrapper (void *arg)
{
gai_start_notify_thread ();
struct notify_func *const n = arg;
void (*func) (sigval_t) = n->func;
sigval_t value = n->value;
free (n);
(*func) (value);
return NULL;
}
int
__gai_notify_only (struct sigevent *sigev, pid_t caller_pid)
{
int result = 0;
/* Send the signal to notify about finished processing of the request. */
if (sigev->sigev_notify == SIGEV_THREAD)
{
/* We have to start a thread. */
pthread_t tid;
pthread_attr_t attr, *pattr;
pattr = (pthread_attr_t *) sigev->sigev_notify_attributes;
if (pattr == NULL)
{
__pthread_attr_init (&attr);
__pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
pattr = &attr;
}
/* SIGEV may be freed as soon as we return, so we cannot let the
notification thread use that pointer. Even though a sigval_t is
only one word and the same size as a void *, we cannot just pass
the value through pthread_create as the argument and have the new
thread run the user's function directly, because on some machines
the calling convention for a union like sigval_t is different from
that for a pointer type like void *. */
struct notify_func *nf = malloc (sizeof *nf);
if (nf == NULL)
result = -1;
else
{
nf->func = sigev->sigev_notify_function;
nf->value = sigev->sigev_value;
if (__pthread_create (&tid, pattr, notify_func_wrapper, nf) < 0)
{
free (nf);
result = -1;
}
}
}
else if (sigev->sigev_notify == SIGEV_SIGNAL)
/* We have to send a signal. */
if (__gai_sigqueue (sigev->sigev_signo, sigev->sigev_value, caller_pid)
< 0)
result = -1;
return result;
}
void
__gai_notify (struct requestlist *req)
{
struct waitlist *waitlist;
/* Now also notify possibly waiting threads. */
waitlist = req->waiting;
while (waitlist != NULL)
{
struct waitlist *next = waitlist->next;
if (waitlist->sigevp == NULL)
{
#ifdef DONT_NEED_GAI_MISC_COND
GAI_MISC_NOTIFY (waitlist);
#else
/* Decrement the counter. */
--*waitlist->counterp;
pthread_cond_signal (waitlist->cond);
#endif
}
else
/* This is part of an asynchronous `getaddrinfo_a' operation. If
this request is the last one, send the signal. */
if (--*waitlist->counterp == 0)
{
__gai_notify_only (waitlist->sigevp, waitlist->caller_pid);
/* This is tricky. See getaddrinfo_a.c for the reason why
this works. */
free ((void *) waitlist->counterp);
}
waitlist = next;
}
}
|
GitWeb