source: rtems-libbsd/freebsd/lib/libc/resolv/mtctxres.c @ bceabc9

4.1155-freebsd-126-freebsd-12freebsd-9.3
Last change on this file since bceabc9 was bceabc9, checked in by Sebastian Huber <sebastian.huber@…>, on 10/09/13 at 20:42:09

Move files to match FreeBSD layout

  • Property mode set to 100644
File size: 2.7 KB
Line 
1#include <sys/cdefs.h>
2__FBSDID("$FreeBSD$");
3
4#include <port_before.h>
5#ifdef DO_PTHREADS
6#include <pthread.h>
7#ifdef _LIBC
8#include <pthread_np.h>
9#endif
10#endif
11#include <errno.h>
12#include <netdb.h>
13#include <stdlib.h>
14#include <string.h>
15#include <resolv_mt.h>
16#include <port_after.h>
17
18#ifdef DO_PTHREADS
19static pthread_key_t    key;
20static int              mt_key_initialized = 0;
21
22static int              __res_init_ctx(void);
23static void             __res_destroy_ctx(void *);
24
25#if defined(sun) && !defined(__GNUC__)
26#pragma init    (_mtctxres_init)
27#endif
28#endif
29
30static mtctxres_t       sharedctx;
31
32#ifdef DO_PTHREADS
33/*
34 * Initialize the TSD key. By doing this at library load time, we're
35 * implicitly running without interference from other threads, so there's
36 * no need for locking.
37 */
38static void
39_mtctxres_init(void) {
40        int pthread_keycreate_ret;
41
42        pthread_keycreate_ret = pthread_key_create(&key, __res_destroy_ctx);
43        if (pthread_keycreate_ret == 0)
44                mt_key_initialized = 1;
45}
46#endif
47
48#ifndef _LIBC
49/*
50 * To support binaries that used the private MT-safe interface in
51 * Solaris 8, we still need to provide the __res_enable_mt()
52 * and __res_disable_mt() entry points. They're do-nothing routines.
53 */
54int
55__res_enable_mt(void) {
56        return (-1);
57}
58
59int
60__res_disable_mt(void) {
61        return (0);
62}
63#endif
64
65#ifdef DO_PTHREADS
66static int
67__res_init_ctx(void) {
68
69        mtctxres_t      *mt;
70        int             ret;
71
72
73        if (pthread_getspecific(key) != 0) {
74                /* Already exists */
75                return (0);
76        }
77
78        if ((mt = malloc(sizeof (mtctxres_t))) == 0) {
79                errno = ENOMEM;
80                return (-1);
81        }
82
83        memset(mt, 0, sizeof (mtctxres_t));
84
85        if ((ret = pthread_setspecific(key, mt)) != 0) {
86                free(mt);
87                errno = ret;
88                return (-1);
89        }
90
91        return (0);
92}
93
94static void
95__res_destroy_ctx(void *value) {
96
97        mtctxres_t      *mt = (mtctxres_t *)value;
98
99        if (mt != 0)
100                free(mt);
101}
102#endif
103
104mtctxres_t *
105___mtctxres(void) {
106#ifdef DO_PTHREADS
107        mtctxres_t      *mt;
108
109#ifdef _LIBC
110        if (pthread_main_np() != 0)
111                return (&sharedctx);
112#endif
113
114        /*
115         * This if clause should only be executed if we are linking
116         * statically.  When linked dynamically _mtctxres_init() should
117         * be called at binding time due the #pragma above.
118         */
119        if (!mt_key_initialized) {
120                static pthread_mutex_t keylock = PTHREAD_MUTEX_INITIALIZER;
121                if (pthread_mutex_lock(&keylock) == 0) {
122                        _mtctxres_init();
123                        (void) pthread_mutex_unlock(&keylock);
124                }
125        }
126
127        /*
128         * If we have already been called in this thread return the existing
129         * context.  Otherwise recreat a new context and return it.  If
130         * that fails return a global context.
131         */
132        if (mt_key_initialized) {
133                if (((mt = pthread_getspecific(key)) != 0) ||
134                    (__res_init_ctx() == 0 &&
135                     (mt = pthread_getspecific(key)) != 0)) {
136                        return (mt);
137                }
138        }
139#endif
140        return (&sharedctx);
141}
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