1 | /* Copyright (C) 2001-2016 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 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <netdb.h> |
20 | #include <pthread.h> |
21 | #include <stdlib.h> |
22 | #include <gai_misc.h> |
23 | |
24 | |
25 | struct notify_func |
26 | { |
27 | void (*func) (sigval_t); |
28 | sigval_t value; |
29 | }; |
30 | |
31 | static void * |
32 | notify_func_wrapper (void *arg) |
33 | { |
34 | gai_start_notify_thread (); |
35 | struct notify_func *const n = arg; |
36 | void (*func) (sigval_t) = n->func; |
37 | sigval_t value = n->value; |
38 | free (n); |
39 | (*func) (value); |
40 | return NULL; |
41 | } |
42 | |
43 | |
44 | int |
45 | internal_function |
46 | __gai_notify_only (struct sigevent *sigev, pid_t caller_pid) |
47 | { |
48 | int result = 0; |
49 | |
50 | /* Send the signal to notify about finished processing of the request. */ |
51 | if (sigev->sigev_notify == SIGEV_THREAD) |
52 | { |
53 | /* We have to start a thread. */ |
54 | pthread_t tid; |
55 | pthread_attr_t attr, *pattr; |
56 | |
57 | pattr = (pthread_attr_t *) sigev->sigev_notify_attributes; |
58 | if (pattr == NULL) |
59 | { |
60 | pthread_attr_init (&attr); |
61 | pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); |
62 | pattr = &attr; |
63 | } |
64 | |
65 | /* SIGEV may be freed as soon as we return, so we cannot let the |
66 | notification thread use that pointer. Even though a sigval_t is |
67 | only one word and the same size as a void *, we cannot just pass |
68 | the value through pthread_create as the argument and have the new |
69 | thread run the user's function directly, because on some machines |
70 | the calling convention for a union like sigval_t is different from |
71 | that for a pointer type like void *. */ |
72 | struct notify_func *nf = malloc (sizeof *nf); |
73 | if (nf == NULL) |
74 | result = -1; |
75 | else |
76 | { |
77 | nf->func = sigev->sigev_notify_function; |
78 | nf->value = sigev->sigev_value; |
79 | if (pthread_create (&tid, pattr, notify_func_wrapper, nf) < 0) |
80 | { |
81 | free (nf); |
82 | result = -1; |
83 | } |
84 | } |
85 | } |
86 | else if (sigev->sigev_notify == SIGEV_SIGNAL) |
87 | /* We have to send a signal. */ |
88 | if (__gai_sigqueue (sigev->sigev_signo, sigev->sigev_value, caller_pid) |
89 | < 0) |
90 | result = -1; |
91 | |
92 | return result; |
93 | } |
94 | |
95 | |
96 | void |
97 | internal_function |
98 | __gai_notify (struct requestlist *req) |
99 | { |
100 | struct waitlist *waitlist; |
101 | |
102 | /* Now also notify possibly waiting threads. */ |
103 | waitlist = req->waiting; |
104 | while (waitlist != NULL) |
105 | { |
106 | struct waitlist *next = waitlist->next; |
107 | |
108 | if (waitlist->sigevp == NULL) |
109 | { |
110 | #ifdef DONT_NEED_GAI_MISC_COND |
111 | GAI_MISC_NOTIFY (waitlist); |
112 | #else |
113 | /* Decrement the counter. */ |
114 | --*waitlist->counterp; |
115 | |
116 | pthread_cond_signal (waitlist->cond); |
117 | #endif |
118 | } |
119 | else |
120 | /* This is part of an asynchronous `getaddrinfo_a' operation. If |
121 | this request is the last one, send the signal. */ |
122 | if (--*waitlist->counterp == 0) |
123 | { |
124 | __gai_notify_only (waitlist->sigevp, waitlist->caller_pid); |
125 | /* This is tricky. See getaddrinfo_a.c for the reason why |
126 | this works. */ |
127 | free ((void *) waitlist->counterp); |
128 | } |
129 | |
130 | waitlist = next; |
131 | } |
132 | } |
133 | |