1/* Copyright (C) 2001-2021 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2001.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <netdb.h>
21#include <pthread.h>
22#include <stdlib.h>
23#include <unistd.h>
24
25#include <gai_misc.h>
26
27
28/* We need this special structure to handle asynchronous I/O. */
29struct async_waitlist
30 {
31 unsigned int counter;
32 struct sigevent sigev;
33 struct waitlist list[0];
34 };
35
36
37int
38getaddrinfo_a (int mode, struct gaicb *list[], int ent, struct sigevent *sig)
39{
40 struct sigevent defsigev;
41 struct requestlist *requests[ent];
42 int cnt;
43 volatile unsigned int total = 0;
44 int result = 0;
45
46 /* Check arguments. */
47 if (mode != GAI_WAIT && mode != GAI_NOWAIT)
48 {
49 __set_errno (EINVAL);
50 return EAI_SYSTEM;
51 }
52
53 if (sig == NULL)
54 {
55 defsigev.sigev_notify = SIGEV_NONE;
56 sig = &defsigev;
57 }
58
59 /* Request the mutex. */
60 pthread_mutex_lock (&__gai_requests_mutex);
61
62 /* Now we can enqueue all requests. Since we already acquired the
63 mutex the enqueue function need not do this. */
64 for (cnt = 0; cnt < ent; ++cnt)
65 if (list[cnt] != NULL)
66 {
67 requests[cnt] = __gai_enqueue_request (list[cnt]);
68
69 if (requests[cnt] != NULL)
70 /* Successfully enqueued. */
71 ++total;
72 else
73 /* Signal that we've seen an error. `errno' and the error code
74 of the gaicb will tell more. */
75 result = EAI_SYSTEM;
76 }
77 else
78 requests[cnt] = NULL;
79
80 if (total == 0)
81 {
82 /* We don't have anything to do except signalling if we work
83 asynchronously. */
84
85 /* Release the mutex. We do this before raising a signal since the
86 signal handler might do a `siglongjmp' and then the mutex is
87 locked forever. */
88 pthread_mutex_unlock (&__gai_requests_mutex);
89
90 if (mode == GAI_NOWAIT)
91 __gai_notify_only (sig,
92 sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0);
93
94 return result;
95 }
96 else if (mode == GAI_WAIT)
97 {
98#ifndef DONT_NEED_GAI_MISC_COND
99 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
100#endif
101 struct waitlist waitlist[ent];
102 int oldstate;
103
104 total = 0;
105 for (cnt = 0; cnt < ent; ++cnt)
106 if (requests[cnt] != NULL)
107 {
108#ifndef DONT_NEED_GAI_MISC_COND
109 waitlist[cnt].cond = &cond;
110#endif
111 waitlist[cnt].next = requests[cnt]->waiting;
112 waitlist[cnt].counterp = &total;
113 waitlist[cnt].sigevp = NULL;
114 waitlist[cnt].caller_pid = 0; /* Not needed. */
115 requests[cnt]->waiting = &waitlist[cnt];
116 ++total;
117 }
118
119 /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
120 points we must be careful. We added entries to the waiting lists
121 which we must remove. So defer cancelation for now. */
122 pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
123
124 while (total > 0)
125 {
126#ifdef DONT_NEED_GAI_MISC_COND
127 int not_used __attribute__ ((unused));
128 GAI_MISC_WAIT (not_used, total, NULL, 1);
129#else
130 pthread_cond_wait (&cond, &__gai_requests_mutex);
131#endif
132 }
133
134 /* Now it's time to restore the cancelation state. */
135 pthread_setcancelstate (oldstate, NULL);
136
137#ifndef DONT_NEED_GAI_MISC_COND
138 /* Release the conditional variable. */
139 if (pthread_cond_destroy (&cond) != 0)
140 /* This must never happen. */
141 abort ();
142#endif
143 }
144 else
145 {
146 struct async_waitlist *waitlist;
147
148 waitlist = (struct async_waitlist *)
149 malloc (sizeof (struct async_waitlist)
150 + (ent * sizeof (struct waitlist)));
151
152 if (waitlist == NULL)
153 result = EAI_AGAIN;
154 else
155 {
156 pid_t caller_pid = sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0;
157 total = 0;
158
159 for (cnt = 0; cnt < ent; ++cnt)
160 if (requests[cnt] != NULL)
161 {
162#ifndef DONT_NEED_GAI_MISC_COND
163 waitlist->list[cnt].cond = NULL;
164#endif
165 waitlist->list[cnt].next = requests[cnt]->waiting;
166 waitlist->list[cnt].counterp = &waitlist->counter;
167 waitlist->list[cnt].sigevp = &waitlist->sigev;
168 waitlist->list[cnt].caller_pid = caller_pid;
169 requests[cnt]->waiting = &waitlist->list[cnt];
170 ++total;
171 }
172
173 waitlist->counter = total;
174 waitlist->sigev = *sig;
175 }
176 }
177
178 /* Release the mutex. */
179 pthread_mutex_unlock (&__gai_requests_mutex);
180
181 return result;
182}
183