/*
 * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include "namespace.h"
#include <machine/tls.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <pthread.h>
#include "un-namespace.h"

#include "thr_private.h"

struct pthread_key _thread_keytable[PTHREAD_KEYS_MAX];
umtx_t  _keytable_lock;
static size_t _pthread_specific_bytes;

int
_pthread_key_create(pthread_key_t *key, void (*destructor) (void *))
{
        pthread_t curthread;
        int i;

        /* User program might be preparing to call pthread_create() */
        _thr_check_init();

        curthread = tls_get_curthread();

        /* Lock the key table: */
        THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
        for (i = 1; i < PTHREAD_KEYS_MAX; i++) {
                if (_thread_keytable[i].allocated == 0) {
                        _thread_keytable[i].allocated = 1;
                        _thread_keytable[i].destructor = destructor;
                        _thread_keytable[i].seqno++;

                        /* Unlock the key table: */
                        THR_LOCK_RELEASE(curthread, &_keytable_lock);
                        *key = i;
                        return (0);
                }

        }
        /* Unlock the key table: */
        THR_LOCK_RELEASE(curthread, &_keytable_lock);
        return (EAGAIN);
}

int
_pthread_key_delete(pthread_key_t key)
{
        pthread_t curthread = tls_get_curthread();
        int ret = 0;

        if ((unsigned int)key < PTHREAD_KEYS_MAX) {
                /* Lock the key table: */
                THR_LOCK_ACQUIRE(curthread, &_keytable_lock);

                if (_thread_keytable[key].allocated)
                        _thread_keytable[key].allocated = 0;
                else
                        ret = EINVAL;

                /* Unlock the key table: */
                THR_LOCK_RELEASE(curthread, &_keytable_lock);
        } else
                ret = EINVAL;
        return (ret);
}

void
_thread_cleanupspecific(void)
{
        pthread_t       curthread = tls_get_curthread();
        void            (*destructor)( void *);
        const void      *data = NULL;
        int             key;
        int             i;

        if (curthread->specific == NULL)
                return;

        /* Lock the key table: */
        THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
        for (i = 0; (i < PTHREAD_DESTRUCTOR_ITERATIONS) &&
            (curthread->specific_data_count > 0); i++) {
                for (key = 0; (key < PTHREAD_KEYS_MAX) &&
                    (curthread->specific_data_count > 0); key++) {
                        destructor = NULL;

                        if (_thread_keytable[key].allocated &&
                            (curthread->specific[key].data != NULL)) {
                                if (curthread->specific[key].seqno ==
                                    _thread_keytable[key].seqno) {
                                        data = curthread->specific[key].data;
                                        destructor = _thread_keytable[key].destructor;
                                }
                                curthread->specific[key].data = NULL;
                                curthread->specific_data_count--;
                        } else if (curthread->specific[key].data != NULL) {
                                /*
                                 * This can happen if the key is deleted via
                                 * pthread_key_delete without first setting the value
                                 * to NULL in all threads. POSIX says that the
                                 * destructor is not invoked in this case.
                                 */
                                curthread->specific[key].data = NULL;
                                curthread->specific_data_count--;
                        }

                        /*
                         * If there is a destructor, call it
                         * with the key table entry unlocked:
                         */
                        if (destructor != NULL) {
                                /*
                                 * Don't hold the lock while calling the
                                 * destructor:
                                 */
                                THR_LOCK_RELEASE(curthread, &_keytable_lock);
                                destructor(__DECONST(void *, data));
                                THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
                        }
                }
        }
        THR_LOCK_RELEASE(curthread, &_keytable_lock);

        munmap(curthread->specific, _pthread_specific_bytes);
        curthread->specific = NULL;

        if (curthread->specific_data_count > 0) {
                stderr_debug("Thread %p has exited with leftover "
                             "thread-specific data after %d destructor "
                             "iterations\n",
                             curthread, PTHREAD_DESTRUCTOR_ITERATIONS);
        }
}

static inline struct pthread_specific_elem *
pthread_key_allocate_data(void)
{
        struct pthread_specific_elem *new_data;
        size_t bytes;
        size_t pgmask;

        bytes = _pthread_specific_bytes;
        if (bytes == 0) {
                pgmask = getpagesize() - 1;
                bytes = sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX;
                bytes = (bytes + pgmask) & ~pgmask;
                _pthread_specific_bytes = bytes;
        }
        new_data = mmap(NULL, bytes, PROT_READ | PROT_WRITE,
                        MAP_ANON | MAP_PRIVATE, -1, 0);
        if (new_data == MAP_FAILED)
                new_data = NULL;

        return (new_data);
}

int
_pthread_setspecific(pthread_key_t key, const void *value)
{
        pthread_t       pthread;
        int             ret = 0;

        /* Point to the running thread: */
        pthread = tls_get_curthread();

        if (pthread->specific ||
            (pthread->specific = pthread_key_allocate_data()) != NULL) {
                if ((unsigned int)key < PTHREAD_KEYS_MAX) {
                        if (_thread_keytable[key].allocated) {
                                if (pthread->specific[key].data == NULL) {
                                        if (value != NULL)
                                                pthread->specific_data_count++;
                                } else if (value == NULL)
                                        pthread->specific_data_count--;
                                pthread->specific[key].data = value;
                                pthread->specific[key].seqno =
                                    _thread_keytable[key].seqno;
                                ret = 0;
                        } else {
                                ret = EINVAL;
                        }
                } else {
                        ret = EINVAL;
                }
        } else {
                ret = ENOMEM;
        }
        return (ret);
}

void *
_pthread_getspecific(pthread_key_t key)
{
        pthread_t       pthread;
        const void      *data;

        /* Point to the running thread: */
        pthread = tls_get_curthread();

        /* Check if there is specific data: */
        if (pthread->specific != NULL && (unsigned int)key < PTHREAD_KEYS_MAX) {
                /* Check if this key has been used before: */
                if (_thread_keytable[key].allocated &&
                    (pthread->specific[key].seqno == _thread_keytable[key].seqno)) {
                        /* Return the value: */
                        data = pthread->specific[key].data;
                } else {
                        /*
                         * This key has not been used before, so return NULL
                         * instead.
                         */
                        data = NULL;
                }
        } else
                /* No specific data has been created, so just return NULL: */
                data = NULL;
        return __DECONST(void *, data);
}

__strong_reference(_pthread_key_create, pthread_key_create);
__strong_reference(_pthread_key_delete, pthread_key_delete);
__strong_reference(_pthread_getspecific, pthread_getspecific);
__strong_reference(_pthread_setspecific, pthread_setspecific);