implement.h

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/*
 * implement.h
 *
 * Definitions that don't need to be public.
 *
 * Keeps all the internals out of pthread.h
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
 *      Copyright(C) 2008 Jason Schmidlapp
 *
 *      Contact Email: [email protected]
 *
 *
 *      Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
 *      Copyright(C) 2008 Jason Schmidlapp
 *
 *      Contact Email: [email protected]
 *
 *
 *      Based upon Pthreads-win32 - POSIX Threads Library for Win32
 *      Copyright(C) 1998 John E. Bossom
 *      Copyright(C) 1999,2005 Pthreads-win32 contributors
 *
 *      Contact Email: [email protected]
 *
 *      The original list of contributors to the Pthreads-win32 project
 *      is contained in the file CONTRIBUTORS.ptw32 included with the
 *      source code distribution. The list can also be seen at the
 *      following World Wide Web location:
 *      http://sources.redhat.com/pthreads-win32/contributors.html
 *
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation; either
 *      version 2 of the License, or (at your option) any later version.
 *
 *      This library 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
 *      Lesser General Public License for more details.
 *
 *      You should have received a copy of the GNU Lesser General Public
 *      License along with this library in the file COPYING.LIB;
 *      if not, write to the Free Software Foundation, Inc.,
 *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */


#ifndef _IMPLEMENT_H
#define _IMPLEMENT_H

#include "pte_osal.h"

/* use local include files during development */
#include "semaphore.h"
#include "sched.h"


typedef enum
{
  /*
   * This enumeration represents the state of the thread;
   * The thread is still "alive" if the numeric value of the
   * state is greater or equal "PThreadStateRunning".
   */
  PThreadStateInitial = 0,  /* Thread not running                   */
  PThreadStateRunning,      /* Thread alive & kicking               */
  PThreadStateSuspended,    /* Thread alive but suspended           */
  PThreadStateCancelPending,    /* Thread alive but is                  */
  /* has cancelation pending.        */
  PThreadStateCanceling,    /* Thread alive but is                  */
  /* in the process of terminating        */
  /* due to a cancellation request        */
  PThreadStateException,    /* Thread alive but exiting             */
  /* due to an exception                  */
  PThreadStateLast
}
PThreadState;


typedef struct pte_thread_t_ pte_thread_t;

struct pte_thread_t_
  {
    pte_osThreadHandle threadId;      /* OS specific thread handle */
    // pthread_t ptHandle;      /* This thread's permanent pthread_t handle */
    pte_thread_t * prevReuse;   /* Links threads on reuse stack */
    volatile PThreadState state;
    void *exitStatus;
    void *parms;
    int ptErrno;
    int detachState;
    pthread_mutex_t threadLock; /* Used for serialised access to public thread state */
    int sched_priority;     /* As set, not as currently is */
    pthread_mutex_t cancelLock; /* Used for async-cancel safety */
    int cancelState;
    int cancelType;
    int cancelEvent;
    jmp_buf start_mark;
    int implicit:
    1;
    void *keys;
    void *nextAssoc;

    unsigned int x;             /* Extra information - reuse count etc */
  };


/*
 * Special value to mark attribute objects as valid.
 */
#define PTE_ATTR_VALID ((unsigned long) 0xC4C0FFEE)

struct pthread_attr_t_
  {
    unsigned long valid;
    void *stackaddr;
    size_t stacksize;
    int detachstate;
    struct sched_param param;
    int inheritsched;
    int contentionscope;
  };


/*
 * ====================
 * ====================
 * Semaphores, Mutexes and Condition Variables
 * ====================
 * ====================
 */

struct sem_t_
  {
    int value;
    pthread_mutex_t lock;
    pte_osSemaphoreHandle sem;
  };

#define PTE_OBJECT_AUTO_INIT ((void *) -1)
#define PTE_OBJECT_INVALID   0

struct pthread_mutex_t_
  {
    pte_osSemaphoreHandle handle;
    int lock_idx;
    /* Provides exclusive access to mutex state
                       via the Interlocked* mechanism.
                        0: unlocked/free.
                        1: locked - no other waiters.
                       -1: locked - with possible other waiters.
                    */
    int recursive_count;        /* Number of unlocks a thread needs to perform
                   before the lock is released (recursive
                   mutexes only). */
    int kind;           /* Mutex type. */
    pthread_t ownerThread;
  };

struct pthread_mutexattr_t_
  {
    int pshared;
    int kind;
  };

/*
 * Possible values, other than PTE_OBJECT_INVALID,
 * for the "interlock" element in a spinlock.
 *
 * In this implementation, when a spinlock is initialised,
 * the number of cpus available to the process is checked.
 * If there is only one cpu then "interlock" is set equal to
 * PTE_SPIN_USE_MUTEX and u.mutex is a initialised mutex.
 * If the number of cpus is greater than 1 then "interlock"
 * is set equal to PTE_SPIN_UNLOCKED and the number is
 * stored in u.cpus. This arrangement allows the spinlock
 * routines to attempt an InterlockedCompareExchange on "interlock"
 * immediately and, if that fails, to try the inferior mutex.
 *
 * "u.cpus" isn't used for anything yet, but could be used at
 * some point to optimise spinlock behaviour.
 */
#define PTE_SPIN_UNLOCKED    (1)
#define PTE_SPIN_LOCKED      (2)
#define PTE_SPIN_USE_MUTEX   (3)

struct pthread_spinlock_t_
  {
    int interlock;      /* Locking element for multi-cpus. */
    union
      {
        int cpus;           /* No. of cpus if multi cpus, or   */
        pthread_mutex_t mutex;  /* mutex if single cpu.            */
      } u;
  };

struct pthread_barrier_t_
  {
    unsigned int nCurrentBarrierHeight;
    unsigned int nInitialBarrierHeight;
    int iStep;
    int pshared;
    sem_t semBarrierBreeched[2];
  };

struct pthread_barrierattr_t_
  {
    int pshared;
  };

struct pthread_key_t_
  {
    unsigned key;
    void (*destructor) (void *);
    pthread_mutex_t keyLock;
    void *threads;
  };


typedef struct ThreadParms ThreadParms;
typedef struct ThreadKeyAssoc ThreadKeyAssoc;

struct ThreadParms
  {
    pthread_t tid;
    void *(*start) (void *);
    void *arg;
  };

struct pthread_cond_t_
  {
    long nWaitersBlocked;       /* Number of threads blocked            */
    long nWaitersGone;      /* Number of threads timed out          */
    long nWaitersToUnblock; /* Number of threads to unblock         */
    sem_t semBlockQueue;        /* Queue up threads waiting for the     */
    /*   condition to become signalled      */
    sem_t semBlockLock;     /* Semaphore that guards access to      */
    /* | waiters blocked count/block queue  */
    /* +-> Mandatory Sync.LEVEL-1           */
    pthread_mutex_t mtxUnblockLock; /* Mutex that guards access to          */
    /* | waiters (to)unblock(ed) counts     */
    /* +-> Optional* Sync.LEVEL-2           */
    pthread_cond_t next;        /* Doubly linked list                   */
    pthread_cond_t prev;
  };


struct pthread_condattr_t_
  {
    int pshared;
  };

#define PTE_RWLOCK_MAGIC 0xfacade2

struct pthread_rwlock_t_
  {
    pthread_mutex_t mtxExclusiveAccess;
    pthread_mutex_t mtxSharedAccessCompleted;
    pthread_cond_t cndSharedAccessCompleted;
    int nSharedAccessCount;
    int nExclusiveAccessCount;
    int nCompletedSharedAccessCount;
    int nMagic;
  };

struct pthread_rwlockattr_t_
  {
    int pshared;
  };

/*
 * MCS lock queue node - see pte_MCS_lock.c
 */
struct pte_mcs_node_t_
  {
    struct pte_mcs_node_t_ **lock;        /* ptr to tail of queue */
    struct pte_mcs_node_t_  *next;        /* ptr to successor in queue */
    unsigned int                       readyFlag;   /* set after lock is released by
                                             predecessor */
    unsigned int                       nextFlag;    /* set after 'next' ptr is set by
                                             successor */
  };

typedef struct pte_mcs_node_t_   pte_mcs_local_node_t;
typedef struct pte_mcs_node_t_  *pte_mcs_lock_t;


struct ThreadKeyAssoc
  {
    /*
     * Purpose:
     *      This structure creates an association between a thread and a key.
     *      It is used to implement the implicit invocation of a user defined
     *      destroy routine for thread specific data registered by a user upon
     *      exiting a thread.
     *
     *      Graphically, the arrangement is as follows, where:
     *
     *         K - Key with destructor
     *            (head of chain is key->threads)
     *         T - Thread that has called pthread_setspecific(Kn)
     *            (head of chain is thread->keys)
     *         A - Association. Each association is a node at the
     *             intersection of two doubly-linked lists.
     *
     *                 T1    T2    T3
     *                 |     |     |
     *                 |     |     |
     *         K1 -----+-----A-----A----->
     *                 |     |     |
     *                 |     |     |
     *         K2 -----A-----A-----+----->
     *                 |     |     |
     *                 |     |     |
     *         K3 -----A-----+-----A----->
     *                 |     |     |
     *                 |     |     |
     *                 V     V     V
     *
     *      Access to the association is guarded by two locks: the key's
     *      general lock (guarding the row) and the thread's general
     *      lock (guarding the column). This avoids the need for a
     *      dedicated lock for each association, which not only consumes
     *      more handles but requires that: before the lock handle can
     *      be released - both the key must be deleted and the thread
     *      must have called the destructor. The two-lock arrangement
     *      allows the resources to be freed as soon as either thread or
     *      key is concluded.
     *
     *      To avoid deadlock: whenever both locks are required, the key
     *      and thread locks are always acquired in the order: key lock
     *      then thread lock. An exception to this exists when a thread
     *      calls the destructors, however this is done carefully to
     *      avoid deadlock.
     *
     *      An association is created when a thread first calls
     *      pthread_setspecific() on a key that has a specified
     *      destructor.
     *
     *      An association is destroyed either immediately after the
     *      thread calls the key destructor function on thread exit, or
     *      when the key is deleted.
     *
     * Attributes:
     *      thread
     *              reference to the thread that owns the
     *              association. This is actually the pointer to the
     *              thread struct itself. Since the association is
     *              destroyed before the thread exits, this can never
     *              point to a different logical thread to the one that
     *              created the assoc, i.e. after thread struct reuse.
     *
     *      key
     *              reference to the key that owns the association.
     *
     *      nextKey
     *              The pthread_t->keys attribute is the head of a
     *              chain of associations that runs through the nextKey
     *              link. This chain provides the 1 to many relationship
     *              between a pthread_t and all pthread_key_t on which
     *              it called pthread_setspecific.
     *
     *      prevKey
     *              Similarly.
     *
     *      nextThread
     *              The pthread_key_t->threads attribute is the head of
     *              a chain of assoctiations that runs through the
     *              nextThreads link. This chain provides the 1 to many
     *              relationship between a pthread_key_t and all the
     *              PThreads that have called pthread_setspecific for
     *              this pthread_key_t.
     *
     *      prevThread
     *              Similarly.
     *
     * Notes:
     *      1)      As soon as either the key or the thread is no longer
     *              referencing the association, it can be destroyed. The
     *              association will be removed from both chains.
     *
     *      2)      An association is only created by
     *              pthread_setspecific if the user provided a
     *              destroyRoutine when they created the key.
     *
     *
     */
    pte_thread_t * thread;
    pthread_key_t key;
    ThreadKeyAssoc *nextKey;
    ThreadKeyAssoc *nextThread;
    ThreadKeyAssoc *prevKey;
    ThreadKeyAssoc *prevThread;
  };

/*
 * Services available through EXCEPTION_PTE_SERVICES
 * and also used [as parameters to pte_throw()] as
 * generic exception selectors.
 */

#define PTE_EPS_EXIT                  (1)
#define PTE_EPS_CANCEL                (2)


/* Useful macros */
#define PTE_MAX(a,b)  ((a)<(b)?(b):(a))
#define PTE_MIN(a,b)  ((a)>(b)?(b):(a))


/* Thread Reuse stack bottom marker. Must not be NULL or any valid pointer to memory. */
#define PTE_THREAD_REUSE_EMPTY ((pte_thread_t *) 1)

extern int pte_processInitialized;
extern pte_thread_t * pte_threadReuseTop;
extern pte_thread_t * pte_threadReuseBottom;
extern pthread_key_t pte_selfThreadKey;
extern pthread_key_t pte_cleanupKey;
extern pthread_cond_t pte_cond_list_head;
extern pthread_cond_t pte_cond_list_tail;

extern int pte_mutex_default_kind;

extern int pte_concurrency;

extern int pte_features;

extern pte_osMutexHandle pte_thread_reuse_lock;
extern pte_osMutexHandle pte_mutex_test_init_lock;
extern pte_osMutexHandle pte_cond_list_lock;
extern pte_osMutexHandle pte_cond_test_init_lock;
extern pte_osMutexHandle pte_rwlock_test_init_lock;
extern pte_osMutexHandle pte_spinlock_test_init_lock;


#ifdef __cplusplus
extern "C"
  {
#endif              /* __cplusplus */

    /*
     * =====================
     * =====================
     * Forward Declarations
     * =====================
     * =====================
     */

    int pte_is_attr (const pthread_attr_t * attr);

    int pte_cond_check_need_init (pthread_cond_t * cond);
    int pte_mutex_check_need_init (pthread_mutex_t * mutex);
    int pte_rwlock_check_need_init (pthread_rwlock_t * rwlock);
    int pte_spinlock_check_need_init (pthread_spinlock_t * lock);

    int pte_processInitialize (void);

    void pte_processTerminate (void);

    void pte_threadDestroy (pthread_t tid);
    void pte_threadExitAndDestroy (pthread_t tid);

    void pte_pop_cleanup_all (int execute);

    pthread_t pte_new (void);

    pthread_t pte_threadReusePop (void);

    void pte_threadReusePush (pthread_t thread);

    int pte_getprocessors (int *count);

    int pte_setthreadpriority (pthread_t thread, int policy, int priority);

    void pte_rwlock_cancelwrwait (void *arg);

    int pte_threadStart (void *vthreadParms);

    void pte_callUserDestroyRoutines (pthread_t thread);

    int pte_tkAssocCreate (pte_thread_t * thread, pthread_key_t key);

    void pte_tkAssocDestroy (ThreadKeyAssoc * assoc);

    int sem_wait_nocancel (sem_t * sem);

    unsigned int pte_relmillisecs (const struct timespec * abstime);

    void pte_mcs_lock_acquire (pte_mcs_lock_t * lock, pte_mcs_local_node_t * node);

    void pte_mcs_lock_release (pte_mcs_local_node_t * node);

    /* Declared in private.c */
    void pte_throw (unsigned int exception);

    int pte_cancellable_wait (pte_osSemaphoreHandle semHandle, unsigned int* timeout);

#define PTE_ATOMIC_EXCHANGE pte_osAtomicExchange
#define PTE_ATOMIC_EXCHANGE_ADD pte_osAtomicExchangeAdd
#define PTE_ATOMIC_COMPARE_EXCHANGE pte_osAtomicCompareExchange
#define PTE_ATOMIC_DECREMENT pte_osAtomicDecrement
#define PTE_ATOMIC_INCREMENT pte_osAtomicIncrement

    int  pte_thread_detach_np();
    int  pte_thread_detach_and_exit_np();


#ifdef __cplusplus
}
#endif              /* __cplusplus */


#endif              /* _IMPLEMENT_H */