text: /* Copyright (c) 2000, 2011 Oracle and/or its affiliates.
     Copyright 2008, 2021, MariaDB Corporation.
  
     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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
  
  /*
    Functions to handle initializating and allocationg of all mysys & debug
    thread variables.
  */
  
  #include "mysys_priv.h"
  #include <m_string.h>
  #include <signal.h>
  
  pthread_key(struct st_my_thread_var*, THR_KEY_mysys);
  mysql_mutex_t THR_LOCK_malloc, THR_LOCK_open,
                THR_LOCK_lock, THR_LOCK_myisam, THR_LOCK_heap,
                THR_LOCK_net, THR_LOCK_charset, THR_LOCK_threads,
                THR_LOCK_myisam_mmap;
  
  mysql_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)
  mysql_mutex_t LOCK_localtime_r;
  #endif
  #ifdef _MSC_VER
  static void install_sigabrt_handler();
  #endif
  
  /** True if @c my_thread_global_init() has been called. */
  static my_bool my_thread_global_init_done= 0;
  /* True if THR_KEY_mysys is created */
  my_bool my_thr_key_mysys_exists= 0;
  
  
  /*
    These are mutexes not used by safe_mutex or my_thr_init.c
  
    We want to free these earlier than other mutex so that safe_mutex
    can detect if all mutex and memory is freed properly.
  */
  
  static void my_thread_init_common_mutex(void)
  {
    mysql_mutex_init(key_THR_LOCK_open, &THR_LOCK_open, MY_MUTEX_INIT_FAST);
    mysql_mutex_init(key_THR_LOCK_lock, &THR_LOCK_lock, MY_MUTEX_INIT_FAST);
    mysql_mutex_init(key_THR_LOCK_myisam, &THR_LOCK_myisam, MY_MUTEX_INIT_SLOW);
    mysql_mutex_init(key_THR_LOCK_myisam_mmap, &THR_LOCK_myisam_mmap, MY_MUTEX_INIT_FAST);
    mysql_mutex_init(key_THR_LOCK_heap, &THR_LOCK_heap, MY_MUTEX_INIT_FAST);
    mysql_mutex_init(key_THR_LOCK_net, &THR_LOCK_net, MY_MUTEX_INIT_FAST);
    mysql_mutex_init(key_THR_LOCK_charset, &THR_LOCK_charset, MY_MUTEX_INIT_FAST);
  #if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
    mysql_mutex_init(key_LOCK_localtime_r, &LOCK_localtime_r, MY_MUTEX_INIT_SLOW);
  #endif
  }
  
  void my_thread_destroy_common_mutex(void)
  {
    mysql_mutex_destroy(&THR_LOCK_open);
    mysql_mutex_destroy(&THR_LOCK_lock);
    mysql_mutex_destroy(&THR_LOCK_myisam);
    mysql_mutex_destroy(&THR_LOCK_myisam_mmap);
    mysql_mutex_destroy(&THR_LOCK_heap);
    mysql_mutex_destroy(&THR_LOCK_net);
    mysql_mutex_destroy(&THR_LOCK_charset);
  #if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
    mysql_mutex_destroy(&LOCK_localtime_r);
  #endif
  }
  
  
  /*
    These mutexes are used by my_thread_init() and after
    my_thread_destroy_mutex()
  */
  
  static void my_thread_init_internal_mutex(void)
  {
    mysql_mutex_init(key_THR_LOCK_threads, &THR_LOCK_threads, MY_MUTEX_INIT_FAST);
    mysql_mutex_init(key_THR_LOCK_malloc, &THR_LOCK_malloc, MY_MUTEX_INIT_FAST);
    mysql_cond_init(key_THR_COND_threads, &THR_COND_threads, NULL);
  }
  
  void my_thread_destroy_internal_mutex(void)
  {
    mysql_mutex_destroy(&THR_LOCK_threads);
    mysql_mutex_destroy(&THR_LOCK_malloc);
    mysql_cond_destroy(&THR_COND_threads);
  }
  
  static void my_thread_init_thr_mutex(struct st_my_thread_var *var)
  {
    mysql_mutex_init(key_my_thread_var_mutex, &var->mutex, MY_MUTEX_INIT_FAST);
    mysql_cond_init(key_my_thread_var_suspend, &var->suspend, NULL);
  }
  
  static void my_thread_destory_thr_mutex(struct st_my_thread_var *var)
  {
    mysql_mutex_destroy(&var->mutex);
    mysql_cond_destroy(&var->suspend);
  }
  
  
  /**
    Re-initialize components initialized early with @c my_thread_global_init.
    Some mutexes were initialized before the instrumentation.
    Destroy + create them again, now that the instrumentation
    is in place.
    This is safe, since this function() is called before creating new threads,
    so the mutexes are not in use.
  */
  void my_thread_global_reinit(void)
  {
    struct st_my_thread_var *tmp;
  
    DBUG_ASSERT(my_thread_global_init_done);
  
  #ifdef HAVE_PSI_INTERFACE
    my_init_mysys_psi_keys();
  #endif
  
    my_thread_destroy_common_mutex();
    my_thread_init_common_mutex();
  
    my_thread_destroy_internal_mutex();
    my_thread_init_internal_mutex();
  
    tmp= my_thread_var;
    DBUG_ASSERT(tmp);
  
    my_thread_destory_thr_mutex(tmp);
    my_thread_init_thr_mutex(tmp);
  }
  
  /*
    initialize thread environment
  
    SYNOPSIS
      my_thread_global_init()
  
    RETURN
      0  ok
      1  error (Couldn't create THR_KEY_mysys)
  */
  
  my_bool my_thread_global_init(void)
  {
    int pth_ret;
  
    /* Normally this should never be called twice */
    DBUG_ASSERT(my_thread_global_init_done == 0);
    if (my_thread_global_init_done)
      return 0;
    my_thread_global_init_done= 1;
  
    /*
      THR_KEY_mysys is deleted in my_end() as DBUG libraries are using it even
      after my_thread_global_end() is called.
      my_thr_key_mysys_exist is used to protect against application like QT
      that calls my_thread_global_init() + my_thread_global_end() multiple times
      without calling my_init() + my_end().
    */
    if (!my_thr_key_mysys_exists &&
        (pth_ret= pthread_key_create(&THR_KEY_mysys, NULL)) != 0)
    {
      fprintf(stderr, "Can't initialize threads: error %d\n", pth_ret);
      return 1;
    }
    my_thr_key_mysys_exists= 1;
  
    /* Mutex used by my_thread_init() and after my_thread_destroy_mutex() */
    my_thread_init_internal_mutex();
  
    if (my_thread_init())
      return 1;
  
  
    my_thread_init_common_mutex();
  
    return 0;
  }
  
  
  /**
     End the mysys thread system. Called when ending the last thread
  */
  
  void my_thread_global_end(void)
  {
    struct timespec abstime;
    my_bool all_threads_killed= 1;
  
    set_timespec(abstime, my_thread_end_wait_time);
    mysql_mutex_lock(&THR_LOCK_threads);
    while (THR_thread_count > 0)
    {
      int error= mysql_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;
      }
    }
    mysql_mutex_unlock(&THR_LOCK_threads);
  
    my_thread_destroy_common_mutex();
  
    /*
      Only destroy the mutex & conditions if we don't have other threads around
      that could use them.
    */
    if (all_threads_killed)
    {
      my_thread_destroy_internal_mutex();
    }
    my_thread_global_init_done= 0;
  }
  
  static my_thread_id thread_id= 0;
  
  /*
    Allocate thread specific memory for the thread, used by mysys and dbug
  
    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
  */
  
  my_bool my_thread_init(void)
  {
    struct st_my_thread_var *tmp;
    my_bool error=0;
  
    if (!my_thread_global_init_done)
      return 1; /* cannot proceed with uninitialized library */
  
  #ifdef EXTRA_DEBUG_THREADS
    fprintf(stderr,"my_thread_init(): pthread_self: %p\n", pthread_self());
  #endif  
  
    if (my_thread_var)
    {
  #ifdef EXTRA_DEBUG_THREADS
      fprintf(stderr,"my_thread_init() called more than once in thread 0x%lx\n",
              (long) pthread_self());
  #endif    
      goto end;
    }
  
  #ifdef _MSC_VER
    install_sigabrt_handler();
  #endif
  
    if (!(tmp= (struct st_my_thread_var *) calloc(1, sizeof(*tmp))))
    {
      error= 1;
      goto end;
    }
    set_mysys_var(tmp);
    tmp->pthread_self= pthread_self();
    my_thread_init_thr_mutex(tmp);
  
    tmp->stack_ends_here= (char*)&tmp +
                           STACK_DIRECTION * (long)my_thread_stack_size;
  
    mysql_mutex_lock(&THR_LOCK_threads);
    tmp->id= tmp->dbug_id= ++thread_id;
    ++THR_thread_count;
    mysql_mutex_unlock(&THR_LOCK_threads);
    tmp->init= 1;
  #ifndef DBUG_OFF
    /* Generate unique name for thread */
    (void) my_thread_name();
  #endif
  
  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= my_thread_var;
  
  #ifdef EXTRA_DEBUG_THREADS
    fprintf(stderr,"my_thread_end(): tmp: %p  pthread_self: %p  thread_id: %ld\n",
  	  tmp, pthread_self(), tmp ? (long) tmp->id : 0L);
  #endif  
  
    /*
      Remove the instrumentation for this thread.
      This must be done before trashing st_my_thread_var,
      because the LF_HASH depends on it.
    */
    PSI_CALL_delete_current_thread();
  
    /*
      We need to disable DBUG early for this thread to ensure that the
      the mutex calls doesn't enable it again
      To this we have to both do DBUG_POP() and also reset THR_KEY_mysys
      as the key is used by DBUG.
    */
    DBUG_POP();
    set_mysys_var(NULL);
  
    if (tmp && tmp->init)
    {
  #if !defined(DBUG_OFF)
      /* tmp->dbug is allocated inside DBUG library */
      if (tmp->dbug)
      {
        free(tmp->dbug);
        tmp->dbug=0;
      }
  #endif
      my_thread_destory_thr_mutex(tmp);
  
      /*
        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() and DBUG_xxxx
      */
      mysql_mutex_lock(&THR_LOCK_threads);
      DBUG_ASSERT(THR_thread_count != 0);
      if (--THR_thread_count == 0)
        mysql_cond_signal(&THR_COND_threads);
      mysql_mutex_unlock(&THR_LOCK_threads);
  
      /* Trash variable so that we can detect false accesses to my_thread_var */
      tmp->init= 2;
      free(tmp);
    }
  }
  
  struct st_my_thread_var *_my_thread_var(void)
  {
    return  my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
  }
  
  int set_mysys_var(struct st_my_thread_var *mysys_var)
  {
    return my_pthread_setspecific_ptr(THR_KEY_mysys, mysys_var);
  }
  
  /****************************************************************************
    Get name of current thread.
  ****************************************************************************/
  
  my_thread_id my_thread_dbug_id()
  {
    /*
      We need to do this test as some system thread may not yet have called
      my_thread_init().
    */
    struct st_my_thread_var *tmp= my_thread_var;
    return tmp ? tmp->dbug_id : 0;
  }
  
  #ifdef DBUG_OFF
  const char *my_thread_name(void)
  {
    return "no_name";
  }
  
  #else
  
  const char *my_thread_name(void)
  {
    char name_buff[100];
    struct st_my_thread_var *tmp=my_thread_var;
    if (!tmp->name[0])
    {
      my_thread_id id= my_thread_dbug_id();
      sprintf(name_buff,"T@%lu", (ulong) id);
      strmake_buf(tmp->name, name_buff);
    }
    return tmp->name;
  }
  
  /* Return pointer to DBUG for holding current state */
  
  extern void **my_thread_var_dbug()
  {
    struct st_my_thread_var *tmp;
    if (!my_thread_global_init_done)
      return NULL;
    tmp= my_thread_var;
    return tmp && tmp->init ? &tmp->dbug : 0;
  }
  #endif /* DBUG_OFF */
  
  /* Return pointer to mutex_in_use */
  
  safe_mutex_t **my_thread_var_mutex_in_use()
  {
    struct st_my_thread_var *tmp;
    if (!my_thread_global_init_done)
      return NULL;
    tmp= my_thread_var;
    return tmp ? &tmp->mutex_in_use : 0;
  }
  
  #ifdef _WIN32
  /*
    In Visual Studio 2005 and later, default SIGABRT handler will overwrite
    any unhandled exception filter set by the application  and will try to
    call JIT debugger. This is not what we want, this we calling __debugbreak
    to stop in debugger, if process is being debugged or to generate 
    EXCEPTION_BREAKPOINT and then handle_segfault will do its magic.
  */
  
  #if (_MSC_VER >= 1400)
  static void my_sigabrt_handler(int sig)
  {
    __debugbreak();
  }
  #endif /*_MSC_VER >=1400 */
  
  static void install_sigabrt_handler(void)
  {
  #if (_MSC_VER >=1400)
    /*abort() should not override our exception filter*/
    _set_abort_behavior(0,_CALL_REPORTFAULT);
    signal(SIGABRT,my_sigabrt_handler);
  #endif /* _MSC_VER >=1400 */
  }
  #endif
  
  #ifdef HAVE_PSI_MUTEX_INTERFACE
  ATTRIBUTE_COLD int psi_mutex_lock(mysql_mutex_t *that,
                                    const char *file, uint line)
  {
    PSI_mutex_locker_state state;
    PSI_mutex_locker *locker= PSI_MUTEX_CALL(start_mutex_wait)
      (&state, that->m_psi, PSI_MUTEX_LOCK, file, line);
  # ifdef SAFE_MUTEX
    int result= safe_mutex_lock(&that->m_mutex, FALSE, file, line);
  # else
    int result= pthread_mutex_lock(&that->m_mutex);
  # endif
    if (locker)
      PSI_MUTEX_CALL(end_mutex_wait)(locker, result);
    return result;
  }
  
  ATTRIBUTE_COLD int psi_mutex_trylock(mysql_mutex_t *that,
                                       const char *file, uint line)
  {
    PSI_mutex_locker_state state;
    PSI_mutex_locker *locker= PSI_MUTEX_CALL(start_mutex_wait)
      (&state, that->m_psi, PSI_MUTEX_TRYLOCK, file, line);
  # ifdef SAFE_MUTEX
    int result= safe_mutex_lock(&that->m_mutex, TRUE, file, line);
  # else
    int result= pthread_mutex_trylock(&that->m_mutex);
  # endif
    if (locker)
      PSI_MUTEX_CALL(end_mutex_wait)(locker, result);
    return result;
  }
  #endif /* HAVE_PSI_MUTEX_INTERFACE */
  
  #ifdef HAVE_PSI_RWLOCK_INTERFACE
  ATTRIBUTE_COLD
  int psi_rwlock_rdlock(mysql_rwlock_t *that, const char *file, uint line)
  {
    PSI_rwlock_locker_state state;
    PSI_rwlock_locker *locker= PSI_RWLOCK_CALL(start_rwlock_rdwait)
      (&state, that->m_psi, PSI_RWLOCK_READLOCK, file, line);
    int result= rw_rdlock(&that->m_rwlock);
    if (locker)
      PSI_RWLOCK_CALL(end_rwlock_rdwait)(locker, result);
    return result;
  }
  
  ATTRIBUTE_COLD
  int psi_rwlock_tryrdlock(mysql_rwlock_t *that, const char *file, uint line)
  {
    PSI_rwlock_locker_state state;
    PSI_rwlock_locker *locker= PSI_RWLOCK_CALL(start_rwlock_rdwait)
      (&state, that->m_psi, PSI_RWLOCK_TRYREADLOCK, file, line);
    int result= rw_tryrdlock(&that->m_rwlock);
    if (locker)
      PSI_RWLOCK_CALL(end_rwlock_rdwait)(locker, result);
    return result;
  }
  
  ATTRIBUTE_COLD
  int psi_rwlock_trywrlock(mysql_rwlock_t *that, const char *file, uint line)
  {
    PSI_rwlock_locker_state state;
    PSI_rwlock_locker *locker= PSI_RWLOCK_CALL(start_rwlock_wrwait)
      (&state, that->m_psi, PSI_RWLOCK_TRYWRITELOCK, file, line);
    int result= rw_trywrlock(&that->m_rwlock);
    if (locker)
      PSI_RWLOCK_CALL(end_rwlock_wrwait)(locker, result);
    return result;
  }
  
  ATTRIBUTE_COLD
  int psi_rwlock_wrlock(mysql_rwlock_t *that, const char *file, uint line)
  {
    PSI_rwlock_locker_state state;
    PSI_rwlock_locker *locker= PSI_RWLOCK_CALL(start_rwlock_wrwait)
      (&state, that->m_psi, PSI_RWLOCK_WRITELOCK, file, line);
    int result= rw_wrlock(&that->m_rwlock);
    if (locker)
      PSI_RWLOCK_CALL(end_rwlock_wrwait)(locker, result);
    return result;
  }
  
  # ifndef DISABLE_MYSQL_PRLOCK_H
  ATTRIBUTE_COLD
  int psi_prlock_rdlock(mysql_prlock_t *that, const char *file, uint line)
  {
    PSI_rwlock_locker_state state;
    PSI_rwlock_locker *locker= PSI_RWLOCK_CALL(start_rwlock_rdwait)
      (&state, that->m_psi, PSI_RWLOCK_READLOCK, file, line);
    int result= rw_pr_rdlock(&that->m_prlock);
    if (locker)
      PSI_RWLOCK_CALL(end_rwlock_rdwait)(locker, result);
    return result;
  }
  
  ATTRIBUTE_COLD
  int psi_prlock_wrlock(mysql_prlock_t *that, const char *file, uint line)
  {
    PSI_rwlock_locker_state state;
    PSI_rwlock_locker *locker= PSI_RWLOCK_CALL(start_rwlock_wrwait)
      (&state, that->m_psi, PSI_RWLOCK_WRITELOCK, file, line);
    int result= rw_pr_wrlock(&that->m_prlock);
    if (locker)
      PSI_RWLOCK_CALL(end_rwlock_wrwait)(locker, result);
    return result;
  }
  # endif /* !DISABLE_MYSQL_PRLOCK_H */
  #endif /* HAVE_PSI_RWLOCK_INTERFACE */
  
  #ifdef HAVE_PSI_COND_INTERFACE
  ATTRIBUTE_COLD int psi_cond_wait(mysql_cond_t *that, mysql_mutex_t *mutex,
                                   const char *file, uint line)
  {
    PSI_cond_locker_state state;
    PSI_cond_locker *locker= PSI_COND_CALL(start_cond_wait)
      (&state, that->m_psi, mutex->m_psi, PSI_COND_WAIT, file, line);
    int result= my_cond_wait(&that->m_cond, &mutex->m_mutex);
    if (locker)
      PSI_COND_CALL(end_cond_wait)(locker, result);
    return result;
  }
  
  ATTRIBUTE_COLD int psi_cond_timedwait(mysql_cond_t *that, mysql_mutex_t *mutex,
                                        const struct timespec *abstime,
                                        const char *file, uint line)
  {
    PSI_cond_locker_state state;
    PSI_cond_locker *locker= PSI_COND_CALL(start_cond_wait)
      (&state, that->m_psi, mutex->m_psi, PSI_COND_TIMEDWAIT, file, line);
    int result= my_cond_timedwait(&that->m_cond, &mutex->m_mutex, abstime);
    if (psi_likely(locker))
      PSI_COND_CALL(end_cond_wait)(locker, result);
    return result;
  }
  #endif /* HAVE_PSI_COND_INTERFACE */
  