/* Copyright (C) 2000 MySQL AB This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* Functions to handle initializating and allocationg of all mysys & debug thread variables. */ #include "mysys_priv.h" #include #include uint thd_lib_detected= 0; #ifdef USE_TLS pthread_key(struct st_my_thread_var*, THR_KEY_mysys); #else pthread_key(struct st_my_thread_var, THR_KEY_mysys); #endif /* USE_TLS */ pthread_mutex_t THR_LOCK_malloc,THR_LOCK_open, THR_LOCK_lock,THR_LOCK_isam,THR_LOCK_myisam,THR_LOCK_heap, THR_LOCK_net, THR_LOCK_charset, THR_LOCK_threads, THR_LOCK_time; pthread_cond_t THR_COND_threads; uint THR_thread_count= 0; uint my_thread_end_wait_time= 5; #if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R) pthread_mutex_t LOCK_localtime_r; #endif #ifndef HAVE_GETHOSTBYNAME_R pthread_mutex_t LOCK_gethostbyname_r; #endif #ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP pthread_mutexattr_t my_fast_mutexattr; #endif #ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP pthread_mutexattr_t my_errorcheck_mutexattr; #endif #ifdef TARGET_OS_LINUX /* Dummy thread spawned in my_thread_global_init() below to avoid race conditions in NPTL pthread_exit code. */ static pthread_handler_t nptl_pthread_exit_hack_handler(void *arg __attribute((unused))) { /* Do nothing! */ pthread_exit(0); return 0; } #endif /* TARGET_OS_LINUX */ static uint get_thread_lib(void); /* initialize thread environment SYNOPSIS my_thread_global_init() RETURN 0 ok 1 error (Couldn't create THR_KEY_mysys) */ bool my_thread_global_init(void) { int pth_ret; thd_lib_detected= get_thread_lib(); if ((pth_ret= pthread_key_create(&THR_KEY_mysys, NULL)) != 0) { fprintf(stderr,"Can't initialize threads: error %d\n", pth_ret); return 1; } #ifdef TARGET_OS_LINUX /* BUG#24507: Race conditions inside current NPTL pthread_exit() implementation. To avoid a possible segmentation fault during concurrent executions of pthread_exit(), a dummy thread is spawned which initializes internal variables of pthread lib. See bug description for a full explanation. TODO: Remove this code when fixed versions of glibc6 are in common use. */ if (thd_lib_detected == THD_LIB_NPTL) { pthread_t dummy_thread; pthread_attr_t dummy_thread_attr; pthread_attr_init(&dummy_thread_attr); pthread_attr_setdetachstate(&dummy_thread_attr, PTHREAD_CREATE_DETACHED); pthread_create(&dummy_thread,&dummy_thread_attr, nptl_pthread_exit_hack_handler, NULL); } #endif /* TARGET_OS_LINUX */ #ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP /* Set mutex type to "fast" a.k.a "adaptive" In this case the thread may steal the mutex from some other thread that is waiting for the same mutex. This will save us some context switches but may cause a thread to 'starve forever' while waiting for the mutex (not likely if the code within the mutex is short). */ pthread_mutexattr_init(&my_fast_mutexattr); pthread_mutexattr_settype(&my_fast_mutexattr, PTHREAD_MUTEX_ADAPTIVE_NP); #endif #ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP /* Set mutex type to "errorcheck" */ pthread_mutexattr_init(&my_errorcheck_mutexattr); pthread_mutexattr_settype(&my_errorcheck_mutexattr, PTHREAD_MUTEX_ERRORCHECK); #endif pthread_mutex_init(&THR_LOCK_malloc,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_open,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_lock,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_isam,MY_MUTEX_INIT_SLOW); pthread_mutex_init(&THR_LOCK_myisam,MY_MUTEX_INIT_SLOW); pthread_mutex_init(&THR_LOCK_heap,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_net,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_charset,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_threads,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_time,MY_MUTEX_INIT_FAST); pthread_cond_init(&THR_COND_threads, NULL); #if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R) pthread_mutex_init(&LOCK_localtime_r,MY_MUTEX_INIT_SLOW); #endif #ifndef HAVE_GETHOSTBYNAME_R pthread_mutex_init(&LOCK_gethostbyname_r,MY_MUTEX_INIT_SLOW); #endif if (my_thread_init()) { my_thread_global_end(); /* Clean up */ return 1; } return 0; } void my_thread_global_end(void) { struct timespec abstime; bool all_threads_killed= 1; set_timespec(abstime, my_thread_end_wait_time); pthread_mutex_lock(&THR_LOCK_threads); while (THR_thread_count > 0) { int error= pthread_cond_timedwait(&THR_COND_threads, &THR_LOCK_threads, &abstime); if (error == ETIMEDOUT || error == ETIME) { #ifdef HAVE_PTHREAD_KILL /* We shouldn't give an error here, because if we don't have pthread_kill(), programs like mysqld can't ensure that all threads are killed when we enter here. */ if (THR_thread_count) fprintf(stderr, "Error in my_thread_global_end(): %d threads didn't exit\n", THR_thread_count); #endif all_threads_killed= 0; break; } } pthread_mutex_unlock(&THR_LOCK_threads); pthread_key_delete(THR_KEY_mysys); #ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP pthread_mutexattr_destroy(&my_fast_mutexattr); #endif #ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP pthread_mutexattr_destroy(&my_errorcheck_mutexattr); #endif pthread_mutex_destroy(&THR_LOCK_malloc); pthread_mutex_destroy(&THR_LOCK_open); pthread_mutex_destroy(&THR_LOCK_lock); pthread_mutex_destroy(&THR_LOCK_isam); pthread_mutex_destroy(&THR_LOCK_myisam); pthread_mutex_destroy(&THR_LOCK_heap); pthread_mutex_destroy(&THR_LOCK_net); pthread_mutex_destroy(&THR_LOCK_time); pthread_mutex_destroy(&THR_LOCK_charset); if (all_threads_killed) { pthread_mutex_destroy(&THR_LOCK_threads); pthread_cond_destroy(&THR_COND_threads); } #if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R) pthread_mutex_destroy(&LOCK_localtime_r); #endif #ifndef HAVE_GETHOSTBYNAME_R pthread_mutex_destroy(&LOCK_gethostbyname_r); #endif } static my_thread_id thread_id= 0; /* Allocate thread specific memory for the thread, used by mysys SYNOPSIS my_thread_init() NOTES We can't use mutex_locks here if we are using windows as we may have compiled the program with SAFE_MUTEX, in which case the checking of mutex_locks will not work until the pthread_self thread specific variable is initialized. This function may called multiple times for a thread, for example if one uses my_init() followed by mysql_server_init(). RETURN 0 ok 1 Fatal error; mysys/dbug functions can't be used */ bool my_thread_init(void) { struct st_my_thread_var *tmp; bool error=0; #ifdef EXTRA_DEBUG_THREADS fprintf(stderr,"my_thread_init(): thread_id: 0x%lx\n", (ulong) pthread_self()); #endif if (pthread_getspecific(THR_KEY_mysys)) { #ifdef EXTRA_DEBUG_THREADS fprintf(stderr,"my_thread_init() called more than once in thread 0x%lx\n", (long) pthread_self()); #endif goto end; } if (!(tmp= (struct st_my_thread_var *) calloc(1, sizeof(*tmp)))) { error= 1; goto end; } pthread_setspecific(THR_KEY_mysys,tmp); tmp->pthread_self= pthread_self(); pthread_mutex_init(&tmp->mutex,MY_MUTEX_INIT_FAST); pthread_cond_init(&tmp->suspend, NULL); tmp->init= 1; pthread_mutex_lock(&THR_LOCK_threads); tmp->id= ++thread_id; ++THR_thread_count; pthread_mutex_unlock(&THR_LOCK_threads); end: return error; } /* Deallocate memory used by the thread for book-keeping SYNOPSIS my_thread_end() NOTE This may be called multiple times for a thread. This happens for example when one calls 'mysql_server_init()' mysql_server_end() and then ends with a mysql_end(). */ void my_thread_end(void) { struct st_my_thread_var *tmp; tmp= (struct st_my_thread_var *)pthread_getspecific(THR_KEY_mysys); #ifdef EXTRA_DEBUG_THREADS fprintf(stderr,"my_thread_end(): tmp: 0x%lx pthread_self: 0x%lx thread_id: %ld\n", (long) tmp, (long) pthread_self(), tmp ? (long) tmp->id : 0L); #endif if (tmp && tmp->init) { #if !defined(__bsdi__) && !defined(__OpenBSD__) /* bsdi and openbsd 3.5 dumps core here */ pthread_cond_destroy(&tmp->suspend); #endif pthread_mutex_destroy(&tmp->mutex); #if defined(USE_TLS) free(tmp); #else tmp->init= 0; #endif /* Decrement counter for number of running threads. We are using this in my_thread_global_end() to wait until all threads have called my_thread_end and thus freed all memory they have allocated in my_thread_init() */ pthread_mutex_lock(&THR_LOCK_threads); assert(THR_thread_count != 0); if (--THR_thread_count == 0) pthread_cond_signal(&THR_COND_threads); pthread_mutex_unlock(&THR_LOCK_threads); } /* The following free has to be done, even if my_thread_var() is 0 */ #if defined(USE_TLS) pthread_setspecific(THR_KEY_mysys,0); #endif } struct st_my_thread_var *_my_thread_var(void) { struct st_my_thread_var *tmp= (struct st_my_thread_var*)pthread_getspecific(THR_KEY_mysys); #if defined(USE_TLS) /* This can only happen in a .DLL */ if (!tmp) { my_thread_init(); tmp=my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys); } #endif return tmp; } /**************************************************************************** Get name of current thread. ****************************************************************************/ my_thread_id my_thread_dbug_id() { return my_thread_var->id; } static uint get_thread_lib(void) { #ifdef _CS_GNU_LIBPTHREAD_VERSION char buff[64]; confstr(_CS_GNU_LIBPTHREAD_VERSION, buff, sizeof(buff)); if (!strncasecmp(buff, "NPTL", 4)) return THD_LIB_NPTL; if (!strncasecmp(buff, "linuxthreads", 12)) return THD_LIB_LT; #endif return THD_LIB_OTHER; }