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//==========================================================================

//

//      pthread.cxx

//

//      POSIX pthreads implementation

//

//==========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos 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; either version 2 or (at your option) any later version.

//

// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):           nickg

// Contributors:        nickg, jlarmour

// Date:                2000-03-27

// Purpose:             POSIX pthread implementation

// Description:         This file contains the implementation of the POSIX pthread

//                      functions.

//              

//              

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include <pkgconf/hal.h>

#include <pkgconf/kernel.h>

#include <pkgconf/posix.h>

#include <pkgconf/isoinfra.h>

#include <pkgconf/libc_startup.h>

#include <cyg/kernel/ktypes.h>         // base kernel types

#include <cyg/infra/cyg_trac.h>        // tracing macros

#include <cyg/infra/cyg_ass.h>         // assertion macros

#include "pprivate.h"                   // POSIX private header

#include <stdlib.h>                     // malloc(), free()

#include <cyg/kernel/sched.hxx>        // scheduler definitions

#include <cyg/kernel/thread.hxx>       // thread definitions

#include <cyg/kernel/clock.hxx>        // clock definitions

#include <cyg/kernel/sched.inl>        // scheduler inlines

//-----------------------------------------------------------------------------

// First check that the configuration contains the elements we need

#ifndef CYGPKG_KERNEL

#error POSIX pthread need eCos kernel

#endif

#ifndef CYGSEM_KERNEL_SCHED_MLQUEUE

#error POSIX pthreads need MLQ scheduler

#endif

#ifndef CYGSEM_KERNEL_SCHED_TIMESLICE

#error POSIX pthreads need timeslicing

#endif

#ifndef CYGVAR_KERNEL_THREADS_DATA

#error POSIX pthreads need per-thread data

#endif

//=============================================================================

// Internal data structures

// Mutex for controlling access to shared data structures

Cyg_Mutex pthread_mutex CYGBLD_POSIX_INIT;

// Array of pthread control structures. A pthread_t object is

// "just" an index into this array.

static pthread_info *thread_table[CYGNUM_POSIX_PTHREAD_THREADS_MAX];

// Count of number of threads in table.

static int pthread_count = 0;

// Count of number of threads that have exited and not been reaped.

static int pthreads_exited;

// Count of number of threads that are waiting to be joined

static int pthreads_tobejoined;

// Per-thread key allocation. This key map has a 1 bit set for each

// key that is free, zero if it is allocated.

#define KEY_MAP_TYPE cyg_uint32

#define KEY_MAP_TYPE_SIZE (sizeof(KEY_MAP_TYPE)*8) // in BITS!

static KEY_MAP_TYPE thread_key[PTHREAD_KEYS_MAX/KEY_MAP_TYPE_SIZE];

static void (*key_destructor[PTHREAD_KEYS_MAX]) (void *);

// Index of next pthread_info to allocate from thread_table array.

static int thread_info_next = 0;

// This is used to make pthread_t values unique even when reusing

// a table slot. This allows CYGNUM_POSIX_PTHREAD_THREADS_MAX to range

// up to 1024.

#define THREAD_ID_COOKIE_INC 0x00000400

#define THREAD_ID_COOKIE_MASK (THREAD_ID_COOKIE_INC-1)

static pthread_t thread_id_cookie = THREAD_ID_COOKIE_INC;

//-----------------------------------------------------------------------------

// Main thread.

#define MAIN_DEFAULT_STACK_SIZE \

  (CYGNUM_LIBC_MAIN_DEFAULT_STACK_SIZE < PTHREAD_STACK_MIN \

              ? PTHREAD_STACK_MIN : CYGNUM_LIBC_MAIN_DEFAULT_STACK_SIZE)

static char main_stack[MAIN_DEFAULT_STACK_SIZE];

// Thread ID of main thread.

static pthread_t main_thread;

//=============================================================================

// Exported variables

int pthread_canceled_dummy_var;           // pointed to by PTHREAD_CANCELED

//=============================================================================

// Internal functions

//-----------------------------------------------------------------------------

// Private version of pthread_self() that returns a pointer to our internal

// control structure.

pthread_info *pthread_self_info(void)

{

    Cyg_Thread *thread = Cyg_Thread::self();

    CYG_CHECK_DATA_PTR(thread, "Illegal current thread");

    pthread_info *info = (pthread_info *)thread->get_data(CYGNUM_KERNEL_THREADS_DATA_POSIX);

//    CYG_CHECK_DATA_PTR(info, "Not a POSIX thread!!!");

    return info;

}

externC pthread_info *pthread_info_id( pthread_t id )

{

    pthread_t index = id & THREAD_ID_COOKIE_MASK;

    pthread_info *info = thread_table[index];

    // Check for a valid entry

    if( info == NULL )

        return NULL;

    // Check that this is a valid entry

    if ( info->state == PTHREAD_STATE_FREE ||

         info->state == PTHREAD_STATE_EXITED )

        return NULL;

    // Check that the entry matches the id

    if( info->id != id ) return NULL;

    // Return the pointer

    return info;

}

//-----------------------------------------------------------------------------

// new operator to allow us to invoke the Cyg_Thread constructor on the

// pthread_info.thread_obj array.

inline void *operator new(size_t size,  cyg_uint8 *ptr) { return (void *)ptr; };

//-----------------------------------------------------------------------------

// Optional memory allocation functions for pthread stacks.

// If there is an implementation of malloc() available, define pthread_malloc()

// and pthread_free() to use it. Otherwise define them to do nothing.

// In the future we may want to add configuration here to permit thread stacks

// to be allocated in a nominated memory pool separate from the standard malloc()

// pool. Hence the (currently redundant) encapsulation of these functions.

#if CYGINT_ISO_MALLOC

static __inline__ CYG_ADDRWORD pthread_malloc( CYG_ADDRWORD size )

{

    return (CYG_ADDRWORD)malloc( size );

}

static __inline__ void pthread_free( CYG_ADDRWORD m )

{

    free( (void *)m );

}

#define PTHREAD_MALLOC

#else

#define pthread_malloc(_x_) (0)

#define pthread_free(_x_)

#endif

//-----------------------------------------------------------------------------

// pthread entry function.

// does some housekeeping and then calls the user's start routine.

static void pthread_entry(CYG_ADDRWORD data)

{

    pthread_info *self = (pthread_info *)data;

    void *retval = self->start_routine(self->start_arg);

    pthread_exit( retval );

}

//-----------------------------------------------------------------------------

// Main entry function.

// This is set as the start_routine of the main thread. It invokes main()

// and if it returns, shuts down the system.

externC void cyg_libc_invoke_main( void );

static void *call_main( void * )

{

    cyg_libc_invoke_main();

    return NULL; // placate compiler

}

//-----------------------------------------------------------------------------

// Check whether there is a cancel pending and if so, whether

// cancellations are enabled. We do it in this order to reduce the

// number of tests in the common case - when no cancellations are

// pending.

// We make this inline so it can be called directly below for speed

static __inline__ int

checkforcancel( void )

{

     pthread_info *self = pthread_self_info();

    if( self != NULL &&

        self->cancelpending &&

        self->cancelstate == PTHREAD_CANCEL_ENABLE )

        return 1;

    else

        return 0;

}

//-----------------------------------------------------------------------------

// POSIX ASR

// This is installed as the ASR for all POSIX threads.

static void posix_asr( CYG_ADDRWORD data )

{

    pthread_info *self = (pthread_info *)data;

#ifdef CYGPKG_POSIX_TIMERS

    // Call into timer subsystem to deliver any pending

    // timer expirations.

    cyg_posix_timer_asr(self);

#endif

#ifdef CYGPKG_POSIX_SIGNALS

    // Call signal subsystem to deliver any signals

    cyg_posix_signal_asr(self);

#endif

    // Check for cancellation

    if( self->cancelpending &&

        self->cancelstate == PTHREAD_CANCEL_ENABLE &&

        self->canceltype == PTHREAD_CANCEL_ASYNCHRONOUS )

    {

        // If we have a pending cancellation, cancellations are

        // enabled and we are in asynchronous mode, then we can do the

        // cancellation processing.  Since pthread_exit() does

        // everything we need to do, we just call that here.

        pthread_exit(PTHREAD_CANCELED);

    }

}

//-----------------------------------------------------------------------------

// The (Grim) Reaper.

// This function is called to tidy up and dispose of any threads that have

// exited. This work must be done from a thread other than the one exiting.

// Note: this function _must_ be called with pthread_mutex locked.

static void pthread_reap()

{

    int i;

    // Loop over the thread table looking for exited threads. The

    // pthreads_exited counter springs us out of this once we have

    // found them all (and keeps us out if there are none to do).

    for( i = 0; pthreads_exited && i < CYGNUM_POSIX_PTHREAD_THREADS_MAX ; i++ )

    {

        pthread_info *thread = thread_table[i];

        if( thread != NULL && thread->state == PTHREAD_STATE_EXITED )

        {

            // The thread has exited, so it is a candidate for being

            // reaped. We have to make sure that the eCos thread has

            // also reached EXITED state before we can tidy it up.

            while( thread->thread->get_state() != Cyg_Thread::EXITED )

            {

                // The eCos thread has not yet exited. This is

                // probably because its priority is too low to allow

                // it to complete.  We fix this here by raising its

                // priority to equal ours and then yielding. This

                // should eventually get it into exited state.

                Cyg_Thread *self = Cyg_Thread::self();

                // Set thread's priority to our current dispatching priority.

                thread->thread->set_priority( self->get_current_priority() );

                // Yield, yield

                self->yield();

                // and keep looping until he exits.

            }

            // At this point we have a thread that we can reap.

            // destroy the eCos thread

            thread->thread->~Cyg_Thread();

            // destroy the joiner condvar

            thread->joiner->~Cyg_Condition_Variable();

#ifdef CYGPKG_POSIX_SIGNALS

            // Destroy signal handling fields

            cyg_posix_thread_sigdestroy( thread );

#endif

            // Free the stack if we allocated it

            if( thread->freestack )

                pthread_free( thread->stackmem );

            // Finally, set the thread table entry to NULL so that it

            // may be reused.

            thread_table[i] = NULL;

            pthread_count--;

            pthreads_exited--;

        }

    }

}

//=============================================================================

// Functions exported to rest of POSIX subsystem.

//-----------------------------------------------------------------------------

// Create the main() thread.

externC void cyg_posix_pthread_start( void )

{

    // Initialize the per-thread data key map.

    for( cyg_ucount32 i = 0; i < (PTHREAD_KEYS_MAX/KEY_MAP_TYPE_SIZE); i++ )

    {

        thread_key[i] = ~0;

    }

    // Create the main thread

    pthread_attr_t attr;

    struct sched_param schedparam;

    schedparam.sched_priority = CYGNUM_POSIX_MAIN_DEFAULT_PRIORITY;

    pthread_attr_init( &attr );

    pthread_attr_setinheritsched( &attr, PTHREAD_EXPLICIT_SCHED );

    pthread_attr_setstackaddr( &attr, &main_stack[sizeof(main_stack)] );

    pthread_attr_setstacksize( &attr, sizeof(main_stack) );

    pthread_attr_setschedpolicy( &attr, SCHED_RR );

    pthread_attr_setschedparam( &attr, &schedparam );

    pthread_create( &main_thread, &attr, call_main, NULL );

}

#ifdef CYGPKG_POSIX_SIGNALS

//-----------------------------------------------------------------------------

// Look for a thread that can accept delivery of any of the signals in

// the mask and release it from any wait it is in.  Since this may be

// called from a DSR, it cannot use any locks internally - any locking

// should be done before the call.

externC void cyg_posix_pthread_release_thread( sigset_t *mask )

{

    int i;

    int count = pthread_count;

    // Loop over the thread table looking for a thread that has a

    // signal mask that does not mask all the signals in mask.

    // FIXME: find a more efficient way of doing this.

    for( i = 0; count > 0 && i < CYGNUM_POSIX_PTHREAD_THREADS_MAX ; i++ )

    {

        pthread_info *thread = thread_table[i];

        if( (thread != NULL) &&

            (thread->state <= PTHREAD_STATE_RUNNING) &&

            ((*mask & ~thread->sigmask) != 0) )

        {

            // This thread can service at least one of the signals in

            // *mask. Knock it out of its wait and make its ASR pending.

            thread->thread->set_asr_pending();

            thread->thread->release();

            break;

        }

        // Decrement count for each valid thread we find.

        if( thread != NULL && thread->state != PTHREAD_STATE_FREE )

            count--;

    }

}

#endif

//=============================================================================

// General thread operations

//-----------------------------------------------------------------------------

// Thread creation and management.

// Create a thread.

externC int pthread_create ( pthread_t *thread,

                             const pthread_attr_t *attr,

                             void *(*start_routine) (void *),

                             void *arg)

{

    PTHREAD_ENTRY();

    PTHREAD_CHECK(thread);

    PTHREAD_CHECK(start_routine);

    pthread_info *self = pthread_self_info();

    pthread_attr_t use_attr;

    // Set use_attr to the set of attributes we are going to

    // actually use. Either those passed in, or the default set.

    if( attr == NULL )

        pthread_attr_init( &use_attr );

    else use_attr = *attr;

    // Adjust the attributes to cope with the setting of inheritsched.

    if( use_attr.inheritsched == PTHREAD_INHERIT_SCHED )

    {

        use_attr.schedpolicy = self->attr.schedpolicy;

        use_attr.schedparam  = self->attr.schedparam;

    }

    CYG_ADDRWORD stackbase, stacksize;

    cyg_bool freestack = false;

    CYG_ADDRWORD stackmem = 0;

    // If the stack size is not valid, we can assume that it is at

    // least PTHREAD_STACK_MIN bytes.

    if( use_attr.stacksize_valid )

        stacksize = use_attr.stacksize;

    else stacksize = PTHREAD_STACK_MIN;

    if( use_attr.stackaddr_valid )

    {

        // Set up stack base and size from supplied arguments.

        // Calculate stack base from address and size.

        // FIXME: Falling stack assumed in pthread_create().

        stackmem = stackbase = (CYG_ADDRWORD)use_attr.stackaddr-stacksize;

    }

    else

    {

#ifdef PTHREAD_MALLOC

        stackmem = stackbase = pthread_malloc( stacksize );

        if( stackmem == 0 )

            PTHREAD_RETURN( EAGAIN );

        freestack = true;

#else        

        PTHREAD_RETURN(EINVAL);

#endif        

    }

    // Get sole access to data structures

    pthread_mutex.lock();

    // Dispose of any dead threads

    pthread_reap();

    // Find a free slot in the thread table

    pthread_info *nthread;

    int thread_next = thread_info_next;

    while( thread_table[thread_next] != NULL )

    {

        thread_next++;

        if( thread_next >= CYGNUM_POSIX_PTHREAD_THREADS_MAX )

            thread_next = 0;

        // check for wrap, and return error if no slots left

        if( thread_next == thread_info_next )

        {

            pthread_mutex.unlock();

            if( freestack )

                pthread_free( stackmem );

            PTHREAD_RETURN(ENOMEM);

        }

    }

    nthread = (pthread_info *)stackbase;

    stackbase += sizeof(pthread_info);

    stacksize -= sizeof(pthread_info);

    thread_table[thread_next] = nthread;

    // Set new next index

    thread_info_next = thread_next;

    // step the cookie

    thread_id_cookie += THREAD_ID_COOKIE_INC;

    // Initialize the table entry

    nthread->state              = use_attr.detachstate == PTHREAD_CREATE_JOINABLE ?

                                  PTHREAD_STATE_RUNNING : PTHREAD_STATE_DETACHED;

    nthread->id                 = thread_next+thread_id_cookie;

    nthread->attr               = use_attr;

    nthread->retval             = 0;

    nthread->start_routine      = start_routine;

    nthread->start_arg          = arg;

    nthread->freestack          = freestack;

    nthread->stackmem           = stackmem;

    nthread->cancelstate        = PTHREAD_CANCEL_ENABLE;

    nthread->canceltype         = PTHREAD_CANCEL_DEFERRED;

    nthread->cancelbuffer       = NULL;

    nthread->cancelpending      = false;

    nthread->thread_data        = NULL;

#ifdef CYGVAR_KERNEL_THREADS_NAME    

    // generate a name for this thread

    char *name = nthread->name;

    static char *name_template = "pthread.00000000";

    pthread_t id = nthread->id;

    for( int i = 0; name_template[i]; i++ ) name[i] = name_template[i];

    // dump the id, in hex into the name.

    for( int i = 15; i >= 8; i-- )

    {

        name[i] = "0123456789ABCDEF"[id&0xF];

        id >>= 4;

    }

#endif

    // Initialize the joiner condition variable

    nthread->joiner = new(nthread->joiner_obj) Cyg_Condition_Variable( pthread_mutex );

#ifdef CYGPKG_POSIX_SIGNALS

    // Initialize signal specific fields.

    cyg_posix_thread_siginit( nthread, self );

#endif

    // create the underlying eCos thread

    nthread->thread = new(&nthread->thread_obj[0])

        Cyg_Thread ( PTHREAD_ECOS_PRIORITY(use_attr.schedparam.sched_priority),

                     pthread_entry,

                     (CYG_ADDRWORD)nthread,

                     name,

                     stackbase,

                     stacksize);

    // Put pointer to pthread_info into eCos thread's per-thread data.

    nthread->thread->set_data( CYGNUM_KERNEL_THREADS_DATA_POSIX, (CYG_ADDRWORD)nthread );

    // Set timeslice enable according to scheduling policy.

    if( use_attr.schedpolicy == SCHED_FIFO )

         nthread->thread->timeslice_disable();

    else nthread->thread->timeslice_enable();

    // set up ASR and data

    nthread->thread->set_asr( posix_asr, (CYG_ADDRWORD)nthread, NULL, NULL );

    // return thread ID

    *thread = nthread->id;

    pthread_count++;

    pthread_mutex.unlock();

    // finally, set the thread going

    nthread->thread->resume();

    PTHREAD_RETURN(0);

}

//-----------------------------------------------------------------------------

// Get current thread id.

externC pthread_t pthread_self ( void )

{

    PTHREAD_ENTRY();

    pthread_info *info = pthread_self_info();

    CYG_CHECK_DATA_PTR(info, "Not a POSIX thread!!!");

    return info->id;

}

//-----------------------------------------------------------------------------

// Compare two thread identifiers.

externC int pthread_equal (pthread_t thread1, pthread_t thread2)

{

    PTHREAD_ENTRY();

    return thread1 == thread2;

}

//-----------------------------------------------------------------------------

// Terminate current thread.

externC void exit(int) CYGBLD_ATTRIB_NORET;

externC void pthread_exit (void *retval)

{

    PTHREAD_ENTRY();

    pthread_info *self = pthread_self_info();

    // Call cancellation handlers. We eat up the buffers as we go in

    // case any of the routines calls pthread_exit() itself.

    while( self->cancelbuffer != NULL )

    {

        struct pthread_cleanup_buffer *buffer = self->cancelbuffer;

        self->cancelbuffer = buffer->prev;

        buffer->routine(buffer->arg);

    }

    if( self->thread_data != NULL )

    {

        // Call per-thread key destructors.

        // The specification of this is that we must continue to call the

        // destructor functions until all the per-thread data values are NULL or

        // we have done it PTHREAD_DESTRUCTOR_ITERATIONS times.

        cyg_bool destructors_called;

        int destructor_iterations = 0;

        do

        {

            destructors_called = false;

            for( cyg_ucount32 key = 0; key < PTHREAD_KEYS_MAX; key++ )

            {

                // Skip unallocated keys

                if( thread_key[key/KEY_MAP_TYPE_SIZE] & 1<<(key%KEY_MAP_TYPE_SIZE) )

                    continue;

                // Skip NULL destructors

                if( key_destructor[key] == NULL ) continue;

                // Skip NULL data values

                if( self->thread_data[key] == NULL ) continue;

                // If it passes all that, call the destructor.

                // Note that NULLing the data value here is new

                // behaviour in the 2001 POSIX standard.

                {

                    void* value = self->thread_data[key];

                    self->thread_data[key] = NULL;

                    key_destructor[key](value);

                }

                // Record that we called a destructor

                destructors_called = true;

            }

            // Count the iteration

            destructor_iterations++;

        } while( destructors_called &&

                 (destructor_iterations <= PTHREAD_DESTRUCTOR_ITERATIONS));

    }

    pthread_mutex.lock();

    // Set the retval for any joiner

    self->retval = retval;