1 #include <port_before.h> 2 #ifdef DO_PTHREADS 3 #include <pthread.h> 4 #ifdef _LIBC 5 #include <pthread_np.h> 6 #endif 7 #endif 8 #include <errno.h> 9 #include <netdb.h> 10 #include <stdlib.h> 11 #include <string.h> 12 #include <resolv_mt.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 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 #ifndef _LIBC 46 /* 47 * To support binaries that used the private MT-safe interface in 48 * Solaris 8, we still need to provide the __res_enable_mt() 49 * and __res_disable_mt() entry points. They're do-nothing routines. 50 */ 51 int 52 __res_enable_mt(void) { 53 return (-1); 54 } 55 56 int 57 __res_disable_mt(void) { 58 return (0); 59 } 60 #endif 61 62 #ifdef DO_PTHREADS 63 static int 64 __res_init_ctx(void) { 65 66 mtctxres_t *mt; 67 int ret; 68 69 70 if (pthread_getspecific(key) != 0) { 71 /* Already exists */ 72 return (0); 73 } 74 75 if ((mt = malloc(sizeof(mtctxres_t))) == NULL) { 76 errno = ENOMEM; 77 return (-1); 78 } 79 80 memset(mt, 0, sizeof (mtctxres_t)); 81 82 if ((ret = pthread_setspecific(key, mt)) != 0) { 83 free(mt); 84 errno = ret; 85 return (-1); 86 } 87 88 return (0); 89 } 90 91 static void 92 __res_destroy_ctx(void *value) { 93 94 free(value); 95 } 96 #endif 97 98 mtctxres_t * 99 ___mtctxres(void) { 100 #ifdef DO_PTHREADS 101 mtctxres_t *mt; 102 103 #ifdef _LIBC 104 if (pthread_main_np() != 0) 105 return (&sharedctx); 106 #endif 107 108 /* 109 * This if clause should only be executed if we are linking 110 * statically. When linked dynamically _mtctxres_init() should 111 * be called at binding time due the #pragma above. 112 */ 113 if (!mt_key_initialized) { 114 static pthread_mutex_t keylock = PTHREAD_MUTEX_INITIALIZER; 115 if (pthread_mutex_lock(&keylock) == 0) { 116 _mtctxres_init(); 117 (void) pthread_mutex_unlock(&keylock); 118 } 119 } 120 121 /* 122 * If we have already been called in this thread return the existing 123 * context. Otherwise recreat a new context and return it. If 124 * that fails return a global context. 125 */ 126 if (mt_key_initialized) { 127 if (((mt = pthread_getspecific(key)) != NULL) || 128 (__res_init_ctx() == 0 && 129 (mt = pthread_getspecific(key)) != NULL)) { 130 return (mt); 131 } 132 } 133 #endif 134 return (&sharedctx); 135 } 136