1 /* $NetBSD: mtctxres.c,v 1.1.1.1 2009/04/12 15:33:56 christos Exp $ */ 2 3 #include <port_before.h> 4 #ifdef DO_PTHREADS 5 #include <pthread.h> 6 #endif 7 #include <errno.h> 8 #include <netdb.h> 9 #include <stdlib.h> 10 #include <string.h> 11 #include <resolv_mt.h> 12 #include <irs.h> 13 #include <port_after.h> 14 15 #ifdef DO_PTHREADS 16 static pthread_key_t key; 17 static int mt_key_initialized = 0; 18 19 static int __res_init_ctx(void); 20 static void __res_destroy_ctx(void *); 21 22 #if defined(sun) && !defined(__GNUC__) 23 #pragma init (_mtctxres_init) 24 #endif 25 #endif 26 27 static mtctxres_t sharedctx; 28 29 #ifdef DO_PTHREADS 30 /* 31 * Initialize the TSD key. By doing this at library load time, we're 32 * implicitly running without interference from other threads, so there's 33 * no need for locking. 34 */ 35 static void _mtctxres_init(void)36_mtctxres_init(void) { 37 int pthread_keycreate_ret; 38 39 pthread_keycreate_ret = pthread_key_create(&key, __res_destroy_ctx); 40 if (pthread_keycreate_ret == 0) 41 mt_key_initialized = 1; 42 } 43 #endif 44 45 /* 46 * To support binaries that used the private MT-safe interface in 47 * Solaris 8, we still need to provide the __res_enable_mt() 48 * and __res_disable_mt() entry points. They're do-nothing routines. 49 */ 50 int __res_enable_mt(void)51__res_enable_mt(void) { 52 return (-1); 53 } 54 55 int __res_disable_mt(void)56__res_disable_mt(void) { 57 return (0); 58 } 59 60 #ifdef DO_PTHREADS 61 static int __res_init_ctx(void)62__res_init_ctx(void) { 63 64 mtctxres_t *mt; 65 int ret; 66 67 68 if (pthread_getspecific(key) != 0) { 69 /* Already exists */ 70 return (0); 71 } 72 73 if ((mt = malloc(sizeof (mtctxres_t))) == 0) { 74 errno = ENOMEM; 75 return (-1); 76 } 77 78 memset(mt, 0, sizeof (mtctxres_t)); 79 80 if ((ret = pthread_setspecific(key, mt)) != 0) { 81 free(mt); 82 errno = ret; 83 return (-1); 84 } 85 86 return (0); 87 } 88 89 static void __res_destroy_ctx(void * value)90__res_destroy_ctx(void *value) { 91 92 mtctxres_t *mt = (mtctxres_t *)value; 93 94 if (mt != 0) 95 free(mt); 96 } 97 #endif 98 99 mtctxres_t * ___mtctxres(void)100___mtctxres(void) { 101 #ifdef DO_PTHREADS 102 mtctxres_t *mt; 103 104 /* 105 * This if clause should only be executed if we are linking 106 * statically. When linked dynamically _mtctxres_init() should 107 * be called at binding time due the #pragma above. 108 */ 109 if (!mt_key_initialized) { 110 static pthread_mutex_t keylock = PTHREAD_MUTEX_INITIALIZER; 111 if (pthread_mutex_lock(&keylock) == 0) { 112 _mtctxres_init(); 113 (void) pthread_mutex_unlock(&keylock); 114 } 115 } 116 117 /* 118 * If we have already been called in this thread return the existing 119 * context. Otherwise recreat a new context and return it. If 120 * that fails return a global context. 121 */ 122 if (mt_key_initialized) { 123 if (((mt = pthread_getspecific(key)) != 0) || 124 (__res_init_ctx() == 0 && 125 (mt = pthread_getspecific(key)) != 0)) { 126 return (mt); 127 } 128 } 129 #endif 130 return (&sharedctx); 131 } 132