mtctxres.c revision 156952
11556Srgrimes#include <port_before.h> 21556Srgrimes#ifdef DO_PTHREADS 31556Srgrimes#include <pthread.h> 41556Srgrimes#endif 51556Srgrimes#include <errno.h> 61556Srgrimes#include <netdb.h> 71556Srgrimes#include <stdlib.h> 81556Srgrimes#include <string.h> 91556Srgrimes#include <resolv_mt.h> 101556Srgrimes#include <irs.h> 111556Srgrimes#include <port_after.h> 121556Srgrimes 131556Srgrimes#ifdef DO_PTHREADS 141556Srgrimesstatic pthread_key_t key; 151556Srgrimesstatic int mt_key_initialized = 0; 161556Srgrimes 171556Srgrimesstatic int __res_init_ctx(void); 181556Srgrimesstatic void __res_destroy_ctx(void *); 191556Srgrimes 201556Srgrimes#if defined(sun) && !defined(__GNUC__) 211556Srgrimes#pragma init (_mtctxres_init) 221556Srgrimes#endif 231556Srgrimes#endif 241556Srgrimes 251556Srgrimesstatic mtctxres_t sharedctx; 261556Srgrimes 271556Srgrimes#ifdef DO_PTHREADS 281556Srgrimes/* 291556Srgrimes * Initialize the TSD key. By doing this at library load time, we're 301556Srgrimes * implicitly running without interference from other threads, so there's 311556Srgrimes * no need for locking. 321556Srgrimes */ 331556Srgrimesstatic void 3420425Ssteve_mtctxres_init(void) { 351556Srgrimes int pthread_keycreate_ret; 361556Srgrimes 371556Srgrimes pthread_keycreate_ret = pthread_key_create(&key, __res_destroy_ctx); 381556Srgrimes if (pthread_keycreate_ret == 0) 391556Srgrimes mt_key_initialized = 1; 4036150Scharnier} 4136150Scharnier#endif 4236150Scharnier 431556Srgrimes/* 4499110Sobrien * To support binaries that used the private MT-safe interface in 4599110Sobrien * Solaris 8, we still need to provide the __res_enable_mt() 461556Srgrimes * and __res_disable_mt() entry points. They're do-nothing routines. 4717987Speter */ 481556Srgrimesint 4917987Speter__res_enable_mt(void) { 5017987Speter return (-1); 511556Srgrimes} 5217525Sache 5359214Simpint 5417525Sache__res_disable_mt(void) { 551556Srgrimes return (0); 561556Srgrimes} 571556Srgrimes 581556Srgrimes#ifdef DO_PTHREADS 591556Srgrimesstatic int 601556Srgrimes__res_init_ctx(void) { 611556Srgrimes 6217987Speter mtctxres_t *mt; 631556Srgrimes int ret; 641556Srgrimes 651556Srgrimes 661556Srgrimes if (pthread_getspecific(key) != 0) { 671556Srgrimes /* Already exists */ 6817987Speter return (0); 691556Srgrimes } 701556Srgrimes 711556Srgrimes if ((mt = malloc(sizeof (mtctxres_t))) == 0) { 721556Srgrimes errno = ENOMEM; 7317987Speter return (-1); 7420425Ssteve } 75223060Sjilles 761556Srgrimes memset(mt, 0, sizeof (mtctxres_t)); 771556Srgrimes 781556Srgrimes if ((ret = pthread_setspecific(key, mt)) != 0) { 79200998Sjilles free(mt); 80221669Sjilles errno = ret; 811556Srgrimes return (-1); 82231790Sjilles } 83222957Sjilles 84213811Sobrien return (0); 851556Srgrimes} 861556Srgrimes 871556Srgrimesstatic void 881556Srgrimes__res_destroy_ctx(void *value) { 891556Srgrimes 901556Srgrimes mtctxres_t *mt = (mtctxres_t *)value; 911556Srgrimes 921556Srgrimes if (mt != 0) 931556Srgrimes free(mt); 9417987Speter} 9590111Simp#endif 9617987Speter 97222957Sjillesmtctxres_t * 981556Srgrimes___mtctxres(void) { 991556Srgrimes#ifdef DO_PTHREADS 1001556Srgrimes mtctxres_t *mt; 10117525Sache 102221669Sjilles /* 1031556Srgrimes * This if clause should only be executed if we are linking 104200998Sjilles * statically. When linked dynamically _mtctxres_init() should 10520425Ssteve * be called at binding time due the #pragma above. 10620425Ssteve */ 10720425Ssteve if (!mt_key_initialized) { 10820425Ssteve static pthread_mutex_t keylock = PTHREAD_MUTEX_INITIALIZER; 10920425Ssteve pthread_mutex_lock(&keylock); 11020425Ssteve _mtctxres_init(); 11120425Ssteve pthread_mutex_unlock(&keylock); 11220425Ssteve } 11320425Ssteve 11420425Ssteve /* 11520425Ssteve * If we have already been called in this thread return the existing 11620425Ssteve * context. Otherwise recreat a new context and return it. If 11720425Ssteve * that fails return a global context. 118220978Sjilles */ 119220978Sjilles if (mt_key_initialized) { 120218306Sjilles if (((mt = pthread_getspecific(key)) != 0) || 1211556Srgrimes (__res_init_ctx() == 0 && 122215567Sjilles (mt = pthread_getspecific(key)) != 0)) { 123215567Sjilles return (mt); 1241556Srgrimes } 1251556Srgrimes } 1261556Srgrimes#endif 1271556Srgrimes return (&sharedctx); 1281556Srgrimes} 1291556Srgrimes