mirror of
https://github.com/MariaDB/server.git
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502 lines
13 KiB
C
502 lines
13 KiB
C
/*
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Copyright (c) 2000-2008 MySQL AB, 2008, 2009 Sun Microsystems, Inc.
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Use is subject to license terms.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/*
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Functions to handle initializating and allocationg of all mysys & debug
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thread variables.
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*/
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#include "mysys_priv.h"
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#include <m_string.h>
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#include <signal.h>
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#ifdef THREAD
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#ifdef USE_TLS
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pthread_key(struct st_my_thread_var*, THR_KEY_mysys);
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#else
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pthread_key(struct st_my_thread_var, THR_KEY_mysys);
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#endif /* USE_TLS */
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pthread_mutex_t THR_LOCK_malloc,THR_LOCK_open,
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THR_LOCK_lock,THR_LOCK_isam,THR_LOCK_myisam,THR_LOCK_heap,
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THR_LOCK_net, THR_LOCK_charset, THR_LOCK_threads, THR_LOCK_time,
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THR_LOCK_myisam_mmap;
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pthread_cond_t THR_COND_threads;
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uint THR_thread_count= 0;
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uint my_thread_end_wait_time= 5;
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#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
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pthread_mutex_t LOCK_localtime_r;
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#endif
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#ifndef HAVE_GETHOSTBYNAME_R
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pthread_mutex_t LOCK_gethostbyname_r;
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#endif
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#ifdef TARGET_OS_LINUX
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/*
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Dummy thread spawned in my_thread_global_init() below to avoid
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race conditions in NPTL pthread_exit code.
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*/
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static pthread_handler_t
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nptl_pthread_exit_hack_handler(void *arg __attribute((unused)))
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{
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/* Do nothing! */
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pthread_exit(0);
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return 0;
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}
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#endif /* TARGET_OS_LINUX */
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/**
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Initialize thread attributes.
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*/
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void my_threadattr_global_init(void)
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{
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#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
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/*
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Set mutex type to "fast" a.k.a "adaptive"
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In this case the thread may steal the mutex from some other thread
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that is waiting for the same mutex. This will save us some
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context switches but may cause a thread to 'starve forever' while
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waiting for the mutex (not likely if the code within the mutex is
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short).
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*/
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pthread_mutexattr_init(&my_fast_mutexattr); /* ?= MY_MUTEX_INIT_FAST */
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pthread_mutexattr_settype(&my_fast_mutexattr,
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PTHREAD_MUTEX_ADAPTIVE_NP);
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#endif
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#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
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/*
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Set mutex type to "errorcheck"
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*/
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pthread_mutexattr_init(&my_errorcheck_mutexattr);
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pthread_mutexattr_settype(&my_errorcheck_mutexattr,
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PTHREAD_MUTEX_ERRORCHECK);
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#endif
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}
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static uint get_thread_lib(void);
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/*
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initialize thread environment
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SYNOPSIS
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my_thread_global_init()
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RETURN
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0 ok
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1 error (Couldn't create THR_KEY_mysys)
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*/
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my_bool my_thread_global_init(void)
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{
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int pth_ret;
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thd_lib_detected= get_thread_lib();
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if ((pth_ret= pthread_key_create(&THR_KEY_mysys, NULL)) != 0)
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{
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fprintf(stderr,"Can't initialize threads: error %d\n", pth_ret);
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return 1;
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}
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#ifdef TARGET_OS_LINUX
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/*
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BUG#24507: Race conditions inside current NPTL pthread_exit()
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implementation.
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To avoid a possible segmentation fault during concurrent
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executions of pthread_exit(), a dummy thread is spawned which
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initializes internal variables of pthread lib. See bug description
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for a full explanation.
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TODO: Remove this code when fixed versions of glibc6 are in common
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use.
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*/
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if (thd_lib_detected == THD_LIB_NPTL)
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{
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pthread_t dummy_thread;
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pthread_attr_t dummy_thread_attr;
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pthread_attr_init(&dummy_thread_attr);
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pthread_attr_setdetachstate(&dummy_thread_attr, PTHREAD_CREATE_JOINABLE);
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if (pthread_create(&dummy_thread,&dummy_thread_attr,
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nptl_pthread_exit_hack_handler, NULL) == 0)
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(void)pthread_join(dummy_thread, NULL);
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}
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#endif /* TARGET_OS_LINUX */
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/* Mutex used by my_thread_init() and after my_thread_destroy_mutex() */
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my_pthread_mutex_init(&THR_LOCK_threads, MY_MUTEX_INIT_FAST,
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"THR_LOCK_threads", MYF_NO_DEADLOCK_DETECTION);
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my_pthread_mutex_init(&THR_LOCK_malloc, MY_MUTEX_INIT_FAST,
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"THR_LOCK_malloc", MYF_NO_DEADLOCK_DETECTION);
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if (my_thread_init())
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return 1;
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/* Mutex uses by mysys */
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pthread_mutex_init(&THR_LOCK_open,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_lock,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_isam,MY_MUTEX_INIT_SLOW);
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pthread_mutex_init(&THR_LOCK_myisam,MY_MUTEX_INIT_SLOW);
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pthread_mutex_init(&THR_LOCK_myisam_mmap,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_heap,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_net,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_charset,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_time,MY_MUTEX_INIT_FAST);
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pthread_cond_init(&THR_COND_threads, NULL);
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#if defined( __WIN__) || defined(OS2)
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win_pthread_init();
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#endif
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#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
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pthread_mutex_init(&LOCK_localtime_r,MY_MUTEX_INIT_SLOW);
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#endif
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#ifndef HAVE_GETHOSTBYNAME_R
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pthread_mutex_init(&LOCK_gethostbyname_r,MY_MUTEX_INIT_SLOW);
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#endif
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return 0;
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}
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/**
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Wait for all threads in system to die
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@fn my_wait_for_other_threads_to_die()
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@param number_of_threads Wait until this number of threads
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@retval 0 Less or equal to number_of_threads left
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@retval 1 Wait failed
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*/
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my_bool my_wait_for_other_threads_to_die(uint number_of_threads)
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{
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struct timespec abstime;
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my_bool all_threads_killed= 1;
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set_timespec(abstime, my_thread_end_wait_time);
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pthread_mutex_lock(&THR_LOCK_threads);
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while (THR_thread_count > number_of_threads)
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{
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int error= pthread_cond_timedwait(&THR_COND_threads, &THR_LOCK_threads,
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&abstime);
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if (error == ETIMEDOUT || error == ETIME)
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{
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all_threads_killed= 0;
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break;
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}
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}
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pthread_mutex_unlock(&THR_LOCK_threads);
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return all_threads_killed;
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}
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/**
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End the mysys thread system. Called when ending the last thread
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*/
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void my_thread_global_end(void)
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{
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my_bool all_threads_killed;
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if (!(all_threads_killed= my_wait_for_other_threads_to_die(0)))
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{
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#ifdef HAVE_PTHREAD_KILL
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/*
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We shouldn't give an error here, because if we don't have
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pthread_kill(), programs like mysqld can't ensure that all threads
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are killed when we enter here.
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*/
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if (THR_thread_count)
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fprintf(stderr,
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"Error in my_thread_global_end(): %d threads didn't exit\n",
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THR_thread_count);
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#endif
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}
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pthread_key_delete(THR_KEY_mysys);
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if (all_threads_killed)
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{
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pthread_mutex_destroy(&THR_LOCK_threads);
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pthread_cond_destroy(&THR_COND_threads);
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pthread_mutex_destroy(&THR_LOCK_malloc);
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}
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}
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/* Free all mutex used by mysys */
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void my_thread_destroy_mutex(void)
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{
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struct st_my_thread_var *tmp;
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tmp= my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
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if (tmp)
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{
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safe_mutex_free_deadlock_data(&tmp->mutex);
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}
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pthread_mutex_destroy(&THR_LOCK_open);
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pthread_mutex_destroy(&THR_LOCK_lock);
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pthread_mutex_destroy(&THR_LOCK_isam);
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pthread_mutex_destroy(&THR_LOCK_myisam);
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pthread_mutex_destroy(&THR_LOCK_myisam_mmap);
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pthread_mutex_destroy(&THR_LOCK_heap);
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pthread_mutex_destroy(&THR_LOCK_net);
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pthread_mutex_destroy(&THR_LOCK_time);
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pthread_mutex_destroy(&THR_LOCK_charset);
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#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
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pthread_mutex_destroy(&LOCK_localtime_r);
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#endif
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#ifndef HAVE_GETHOSTBYNAME_R
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pthread_mutex_destroy(&LOCK_gethostbyname_r);
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#endif
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}
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static my_thread_id thread_id= 0;
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/*
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Allocate thread specific memory for the thread, used by mysys and dbug
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SYNOPSIS
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my_thread_init()
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NOTES
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We can't use mutex_locks here if we are using windows as
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we may have compiled the program with SAFE_MUTEX, in which
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case the checking of mutex_locks will not work until
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the pthread_self thread specific variable is initialized.
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This function may called multiple times for a thread, for example
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if one uses my_init() followed by mysql_server_init().
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RETURN
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0 ok
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1 Fatal error; mysys/dbug functions can't be used
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*/
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my_bool my_thread_init(void)
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{
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struct st_my_thread_var *tmp;
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my_bool error=0;
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#ifdef EXTRA_DEBUG_THREADS
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fprintf(stderr,"my_thread_init(): thread_id: 0x%lx\n",
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(ulong) pthread_self());
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#endif
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#if !defined(__WIN__) || defined(USE_TLS)
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if (my_pthread_getspecific(struct st_my_thread_var *,THR_KEY_mysys))
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{
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#ifdef EXTRA_DEBUG_THREADS
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fprintf(stderr,"my_thread_init() called more than once in thread 0x%lx\n",
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(long) pthread_self());
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#endif
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goto end;
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}
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if (!(tmp= (struct st_my_thread_var *) calloc(1, sizeof(*tmp))))
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{
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error= 1;
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goto end;
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}
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pthread_setspecific(THR_KEY_mysys,tmp);
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#else /* defined(__WIN__) && !(defined(USE_TLS) */
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/*
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Skip initialization if the thread specific variable is already initialized
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*/
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if (THR_KEY_mysys.init)
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goto end;
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tmp= &THR_KEY_mysys;
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#endif
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#if defined(__WIN__) && defined(EMBEDDED_LIBRARY)
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tmp->pthread_self= (pthread_t) getpid();
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#else
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tmp->pthread_self= pthread_self();
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#endif
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my_pthread_mutex_init(&tmp->mutex, MY_MUTEX_INIT_FAST, "mysys_var->mutex",
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0);
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pthread_cond_init(&tmp->suspend, NULL);
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tmp->stack_ends_here= (char*)&tmp +
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STACK_DIRECTION * (long)my_thread_stack_size;
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pthread_mutex_lock(&THR_LOCK_threads);
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tmp->id= ++thread_id;
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++THR_thread_count;
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pthread_mutex_unlock(&THR_LOCK_threads);
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tmp->init= 1;
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#ifndef DBUG_OFF
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/* Generate unique name for thread */
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(void) my_thread_name();
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#endif
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end:
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return error;
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}
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/*
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Deallocate memory used by the thread for book-keeping
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SYNOPSIS
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my_thread_end()
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NOTE
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This may be called multiple times for a thread.
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This happens for example when one calls 'mysql_server_init()'
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mysql_server_end() and then ends with a mysql_end().
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*/
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void my_thread_end(void)
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{
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struct st_my_thread_var *tmp;
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tmp= my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
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#ifdef EXTRA_DEBUG_THREADS
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fprintf(stderr,"my_thread_end(): tmp: 0x%lx pthread_self: 0x%lx thread_id: %ld\n",
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(long) tmp, (long) pthread_self(), tmp ? (long) tmp->id : 0L);
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#endif
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if (tmp && tmp->init)
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{
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#if !defined(__bsdi__) && !defined(__OpenBSD__)
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/* bsdi and openbsd 3.5 dumps core here */
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pthread_cond_destroy(&tmp->suspend);
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#endif
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pthread_mutex_destroy(&tmp->mutex);
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#if !defined(DBUG_OFF)
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/* tmp->dbug is allocated inside DBUG library */
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if (tmp->dbug)
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{
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DBUG_POP();
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free(tmp->dbug);
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tmp->dbug=0;
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}
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#endif
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#if !defined(__WIN__) || defined(USE_TLS)
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#ifndef DBUG_OFF
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/* To find bugs when accessing unallocated data */
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bfill(tmp, sizeof(tmp), 0x8F);
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#endif
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free(tmp);
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#else
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tmp->init= 0;
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#endif
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#if !defined(__WIN__) || defined(USE_TLS)
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pthread_setspecific(THR_KEY_mysys,0);
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#endif
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/*
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Decrement counter for number of running threads. We are using this
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in my_thread_global_end() to wait until all threads have called
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my_thread_end and thus freed all memory they have allocated in
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my_thread_init() and DBUG_xxxx
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*/
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pthread_mutex_lock(&THR_LOCK_threads);
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DBUG_ASSERT(THR_thread_count != 0);
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if (--THR_thread_count == 0)
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pthread_cond_signal(&THR_COND_threads);
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pthread_mutex_unlock(&THR_LOCK_threads);
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}
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else
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{
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#if !defined(__WIN__) || defined(USE_TLS)
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pthread_setspecific(THR_KEY_mysys,0);
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#endif
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}
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}
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struct st_my_thread_var *_my_thread_var(void)
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{
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return my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
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}
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#ifndef DBUG_OFF
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/* Return pointer to DBUG for holding current state */
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extern void **my_thread_var_dbug()
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{
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struct st_my_thread_var *tmp=
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my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
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return tmp && tmp->init ? &tmp->dbug : 0;
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}
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#endif
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/* Return pointer to mutex_in_use */
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safe_mutex_t **my_thread_var_mutex_in_use()
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{
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struct st_my_thread_var *tmp=
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my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
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return tmp ? &tmp->mutex_in_use : 0;
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}
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/****************************************************************************
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Get name of current thread.
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****************************************************************************/
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my_thread_id my_thread_dbug_id()
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{
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return my_thread_var->id;
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}
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#ifdef DBUG_OFF
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const char *my_thread_name(void)
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{
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return "no_name";
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}
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#else
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const char *my_thread_name(void)
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{
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char name_buff[100];
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struct st_my_thread_var *tmp=my_thread_var;
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if (!tmp->name[0])
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{
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my_thread_id id= my_thread_dbug_id();
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sprintf(name_buff,"T@%lu", (ulong) id);
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strmake(tmp->name,name_buff,THREAD_NAME_SIZE);
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}
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return tmp->name;
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}
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#endif /* DBUG_OFF */
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static uint get_thread_lib(void)
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{
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#ifdef _CS_GNU_LIBPTHREAD_VERSION
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char buff[64];
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confstr(_CS_GNU_LIBPTHREAD_VERSION, buff, sizeof(buff));
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if (!strncasecmp(buff, "NPTL", 4))
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return THD_LIB_NPTL;
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if (!strncasecmp(buff, "linuxthreads", 12))
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return THD_LIB_LT;
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#endif
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return THD_LIB_OTHER;
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}
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#endif /* THREAD */
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