/*
 * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
 * Copyright (c) 2006 David Xu <davidxu@freebsd.org>.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by John Birrell.
 * 4. 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 <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/queue.h>
#include <pthread.h>
#include "un-namespace.h"

#include "thr_private.h"

#ifdef _PTHREADS_DEBUGGING

#include <stdio.h>
#include <stdarg.h>
#include <sys/file.h>

#endif

#if defined(_PTHREADS_INVARIANTS)
#define MUTEX_INIT_LINK(m)              do {            \
        (m)->m_qe.tqe_prev = NULL;                      \
        (m)->m_qe.tqe_next = NULL;                      \
} while (0)
#define MUTEX_ASSERT_IS_OWNED(m)        do {            \
        if ((m)->m_qe.tqe_prev == NULL)                 \
                PANIC("mutex is not on list");          \
} while (0)
#define MUTEX_ASSERT_NOT_OWNED(m)       do {            \
        if (((m)->m_qe.tqe_prev != NULL) ||             \
            ((m)->m_qe.tqe_next != NULL))               \
                PANIC("mutex is on list");              \
} while (0)
#define THR_ASSERT_NOT_IN_SYNCQ(thr)    do {            \
        THR_ASSERT(((thr)->sflags & THR_FLAGS_IN_SYNCQ) == 0, \
            "thread in syncq when it shouldn't be.");   \
} while (0);
#else
#define MUTEX_INIT_LINK(m)
#define MUTEX_ASSERT_IS_OWNED(m)
#define MUTEX_ASSERT_NOT_OWNED(m)
#define THR_ASSERT_NOT_IN_SYNCQ(thr)
#endif

#define THR_IN_MUTEXQ(thr)      (((thr)->sflags & THR_FLAGS_IN_SYNCQ) != 0)
#define MUTEX_DESTROY(m) do {           \
        __free(m);                      \
} while (0)

umtx_t  _mutex_static_lock;

#ifdef _PTHREADS_DEBUGGING

static
void
mutex_log(const char *ctl, ...)
{
        char buf[256];
        va_list va;
        size_t len;

        va_start(va, ctl);
        len = vsnprintf(buf, sizeof(buf), ctl, va);
        va_end(va);
        _thr_log(buf, len);
}

#else

static __inline
void
mutex_log(const char *ctl __unused, ...)
{
}

#endif

#ifdef _PTHREADS_DEBUGGING2

static void
mutex_log2(pthread_t curthread, pthread_mutex_t m, int op)
{
        if (curthread) {
                if (curthread->tid < 32)
                        m->m_lastop[curthread->tid] =
                                (__sys_getpid() << 16) | op;
        } else {
                        m->m_lastop[0] =
                                (__sys_getpid() << 16) | op;
        }
}

#else

static __inline
void
mutex_log2(pthread_t curthread __unused,
           pthread_mutex_t m __unused, int op __unused)
{
}

#endif

/*
 * Prototypes
 */
static int      mutex_self_trylock(pthread_mutex_t);
static int      mutex_self_lock(pthread_mutex_t,
                        const struct timespec *abstime);
static int      mutex_unlock_common(pthread_mutex_t *);

int __pthread_mutex_init(pthread_mutex_t *mutex,
        const pthread_mutexattr_t *mutex_attr);
int __pthread_mutex_trylock(pthread_mutex_t *mutex);
int __pthread_mutex_lock(pthread_mutex_t *mutex);
int __pthread_mutex_timedlock(pthread_mutex_t *mutex,
        const struct timespec *abs_timeout);

static int
mutex_check_attr(const struct __pthread_mutexattr_s *attr)
{
        if (attr->m_type < PTHREAD_MUTEX_ERRORCHECK ||
            attr->m_type >= PTHREAD_MUTEX_TYPE_MAX)
                return (EINVAL);
        if (attr->m_protocol < PTHREAD_PRIO_NONE ||
            attr->m_protocol > PTHREAD_PRIO_PROTECT)
                return (EINVAL);
        return (0);
}

static void
mutex_init_body(pthread_mutex_t pmutex,
    const struct __pthread_mutexattr_s *attr, int private)
{
        _thr_umtx_init(&pmutex->m_lock);
        pmutex->m_type = attr->m_type;
        pmutex->m_protocol = attr->m_protocol;
        TAILQ_INIT(&pmutex->m_queue);
        mutex_log2(tls_get_curthread(), pmutex, 32);
        pmutex->m_owner = NULL;
        pmutex->m_flags = attr->m_flags | MUTEX_FLAGS_INITED;
        if (private)
                pmutex->m_flags |= MUTEX_FLAGS_PRIVATE;
        pmutex->m_count = 0;
        pmutex->m_refcount = 0;
        if (attr->m_protocol == PTHREAD_PRIO_PROTECT)
                pmutex->m_prio = attr->m_ceiling;
        else
                pmutex->m_prio = -1;
        pmutex->m_saved_prio = 0;
        MUTEX_INIT_LINK(pmutex);
}

static int
mutex_init(pthread_mutex_t *mutex,
    const pthread_mutexattr_t *mutex_attr, int private)
{
        const struct __pthread_mutexattr_s *attr;
        pthread_mutex_t pmutex;
        int error;

        if (mutex_attr == NULL) {
                attr = &_pthread_mutexattr_default;
        } else {
                attr = *mutex_attr;
                error = mutex_check_attr(attr);
                if (error != 0)
                        return (error);
        }

        pmutex = __malloc(sizeof(struct __pthread_mutex_s));
        if (pmutex == NULL)
                return (ENOMEM);
        mutex_init_body(pmutex, attr, private);
        *mutex = pmutex;
        return (0);
}

static int
init_static(pthread_t thread, pthread_mutex_t *mutex)
{
        int ret;

        THR_LOCK_ACQUIRE(thread, &_mutex_static_lock);

        if (*mutex == NULL)
                ret = mutex_init(mutex, NULL, 0);
        else
                ret = 0;
        THR_LOCK_RELEASE(thread, &_mutex_static_lock);

        return (ret);
}

static int
init_static_private(pthread_t thread, pthread_mutex_t *mutex)
{
        int ret;

        THR_LOCK_ACQUIRE(thread, &_mutex_static_lock);

        if (*mutex == NULL)
                ret = mutex_init(mutex, NULL, 1);
        else
                ret = 0;

        THR_LOCK_RELEASE(thread, &_mutex_static_lock);

        return (ret);
}

int
_pthread_mutex_init(pthread_mutex_t * __restrict mutex,
    const pthread_mutexattr_t * __restrict mutex_attr)
{
        return mutex_init(mutex, mutex_attr, 1);
}

int
__pthread_mutex_init(pthread_mutex_t *mutex,
    const pthread_mutexattr_t *mutex_attr)
{
        return mutex_init(mutex, mutex_attr, 0);
}

#if 0
int
_mutex_reinit(pthread_mutex_t *mutexp)
{
        pthread_mutex_t mutex = *mutexp;

        _thr_umtx_init(&mutex->m_lock);
        TAILQ_INIT(&mutex->m_queue);
        MUTEX_INIT_LINK(mutex);
        mutex_log2(tls_get_curthread(), mutex, 33);
        mutex->m_owner = NULL;
        mutex->m_count = 0;
        mutex->m_refcount = 0;
        mutex->m_prio = 0;
        mutex->m_saved_prio = 0;

        return (0);
}
#endif

void
_mutex_fork(pthread_t curthread, lwpid_t tid)
{
        pthread_mutex_t m;

        TAILQ_FOREACH(m, &curthread->mutexq, m_qe)
                m->m_lock = tid;
}

int
_pthread_mutex_destroy(pthread_mutex_t *mutex)
{
        pthread_t curthread = tls_get_curthread();
        pthread_mutex_t m;
        int ret = 0;

        if (mutex == NULL) {
                ret = EINVAL;
        } else if (*mutex == NULL) {
                ret = 0;
        } else {
                /*
                 * Try to lock the mutex structure, we only need to
                 * try once, if failed, the mutex is in use.
                 */
                ret = THR_UMTX_TRYLOCK_PERSIST(curthread, &(*mutex)->m_lock);
                if (ret)
                        return (ret);

                /*
                 * Check mutex other fields to see if this mutex is
                 * in use. Mostly for prority mutex types, or there
                 * are condition variables referencing it.
                 */
                if (((*mutex)->m_owner != NULL) ||
                    (TAILQ_FIRST(&(*mutex)->m_queue) != NULL) ||
                    ((*mutex)->m_refcount != 0)) {
                        THR_UMTX_UNLOCK_PERSIST(curthread, &(*mutex)->m_lock);
                        ret = EBUSY;
                } else {
                        /*
                         * Save a pointer to the mutex so it can be free'd
                         * and set the caller's pointer to NULL:
                         */
                        m = *mutex;
                        *mutex = NULL;

                        /* Unlock the mutex structure: */
                        THR_UMTX_UNLOCK_PERSIST(curthread, &m->m_lock);

                        /*
                         * Free the memory allocated for the mutex
                         * structure:
                         */
                        MUTEX_ASSERT_NOT_OWNED(m);
                        MUTEX_DESTROY(m);
                }
        }

        /* Return the completion status: */
        return (ret);
}

static int
mutex_trylock_common(pthread_t curthread, pthread_mutex_t *mutex)
{
        pthread_mutex_t m;
        int ret;

        m = *mutex;
        mutex_log("mutex_lock_trylock_common %p\n", m);
        ret = THR_UMTX_TRYLOCK_PERSIST(curthread, &m->m_lock);
        if (ret == 0) {
                mutex_log2(curthread, m, 1);
                m->m_owner = curthread;
                /* Add to the list of owned mutexes: */
                MUTEX_ASSERT_NOT_OWNED(m);
                TAILQ_INSERT_TAIL(&curthread->mutexq, m, m_qe);
        } else if (m->m_owner == curthread) {
                mutex_log2(curthread, m, 2);
                ret = mutex_self_trylock(m);
        } /* else {} */
        mutex_log("mutex_lock_trylock_common %p (returns %d)\n", m, ret);

        return (ret);
}

int
__pthread_mutex_trylock(pthread_mutex_t *m)
{
        pthread_t curthread = tls_get_curthread();
        int ret;

        if (__predict_false(m == NULL))
                return(EINVAL);
        /*
         * If the mutex is statically initialized, perform the dynamic
         * initialization:
         */
        if (__predict_false(*m == NULL)) {
                ret = init_static(curthread, m);
                if (__predict_false(ret != 0))
                        return (ret);
        }
        return (mutex_trylock_common(curthread, m));
}

int
_pthread_mutex_trylock(pthread_mutex_t *m)
{
        pthread_t curthread = tls_get_curthread();
        int     ret = 0;

        /*
         * If the mutex is statically initialized, perform the dynamic
         * initialization marking the mutex private (delete safe):
         */
        if (__predict_false(*m == NULL)) {
                ret = init_static_private(curthread, m);
                if (__predict_false(ret != 0))
                        return (ret);
        }
        return (mutex_trylock_common(curthread, m));
}

static int
mutex_lock_common(pthread_t curthread, pthread_mutex_t *mutex,
        const struct timespec * abstime)
{
        struct  timespec ts, ts2;
        pthread_mutex_t m;
        int     ret = 0;

        m = *mutex;
        mutex_log("mutex_lock_common %p\n", m);
        ret = THR_UMTX_TRYLOCK_PERSIST(curthread, &m->m_lock);
        if (ret == 0) {
                mutex_log2(curthread, m, 3);
                m->m_owner = curthread;
                /* Add to the list of owned mutexes: */
                MUTEX_ASSERT_NOT_OWNED(m);
                TAILQ_INSERT_TAIL(&curthread->mutexq, m, m_qe);
        } else if (m->m_owner == curthread) {
                ret = mutex_self_lock(m, abstime);
        } else {
                if (abstime == NULL) {
                        THR_UMTX_LOCK_PERSIST(curthread, &m->m_lock);
                        ret = 0;
                } else if (__predict_false(
                        abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
                        abstime->tv_nsec >= 1000000000)) {
                                ret = EINVAL;
                } else {
                        clock_gettime(CLOCK_REALTIME, &ts);
                        timespecsub(abstime, &ts, &ts2);
                        ret = THR_UMTX_TIMEDLOCK_PERSIST(curthread,
                                                         &m->m_lock, &ts2);
                }
                if (ret == 0) {
                        mutex_log2(curthread, m, 4);
                        m->m_owner = curthread;
                        /* Add to the list of owned mutexes: */
                        MUTEX_ASSERT_NOT_OWNED(m);
                        TAILQ_INSERT_TAIL(&curthread->mutexq, m, m_qe);
                }
        }
        mutex_log("mutex_lock_common %p (returns %d) lock %d,%d\n",
                  m, ret, m->m_lock, m->m_count);
        return (ret);
}

int
__pthread_mutex_lock(pthread_mutex_t *m)
{
        pthread_t curthread;
        int     ret;

        if (__predict_false(m == NULL))
                return(EINVAL);

        /*
         * If the mutex is statically initialized, perform the dynamic
         * initialization:
         */
        curthread = tls_get_curthread();
        if (__predict_false(*m == NULL)) {
                ret = init_static(curthread, m);
                if (__predict_false(ret))
                        return (ret);
        }
        return (mutex_lock_common(curthread, m, NULL));
}

int
_pthread_mutex_lock(pthread_mutex_t *m)
{
        pthread_t curthread;
        int     ret;

        _thr_check_init();

        if (__predict_false(m == NULL))
                return(EINVAL);

        /*
         * If the mutex is statically initialized, perform the dynamic
         * initialization marking it private (delete safe):
         */
        curthread = tls_get_curthread();
        if (__predict_false(*m == NULL)) {
                ret = init_static_private(curthread, m);
                if (__predict_false(ret))
                        return (ret);
        }
        return (mutex_lock_common(curthread, m, NULL));
}

int
__pthread_mutex_timedlock(pthread_mutex_t * __restrict m,
    const struct timespec * __restrict abs_timeout)
{
        pthread_t curthread;
        int     ret;

        _thr_check_init();

        if (__predict_false(m == NULL))
                return(EINVAL);

        /*
         * If the mutex is statically initialized, perform the dynamic
         * initialization:
         */
        curthread = tls_get_curthread();
        if (__predict_false(*m == NULL)) {
                ret = init_static(curthread, m);
                if (__predict_false(ret))
                        return (ret);
        }
        return (mutex_lock_common(curthread, m, abs_timeout));
}

int
_pthread_mutex_timedlock(pthread_mutex_t *m,
        const struct timespec *abs_timeout)
{
        pthread_t curthread;
        int     ret;

        if (__predict_false(m == NULL))
                return(EINVAL);

        curthread = tls_get_curthread();

        /*
         * If the mutex is statically initialized, perform the dynamic
         * initialization marking it private (delete safe):
         */
        if (__predict_false(*m == NULL)) {
                ret = init_static_private(curthread, m);
                if (__predict_false(ret))
                        return (ret);
        }
        return (mutex_lock_common(curthread, m, abs_timeout));
}

int
_pthread_mutex_unlock(pthread_mutex_t *m)
{
        if (__predict_false(m == NULL))
                return(EINVAL);
        return (mutex_unlock_common(m));
}

static int
mutex_self_trylock(pthread_mutex_t m)
{
        int     ret;

        switch (m->m_type) {
        /* case PTHREAD_MUTEX_DEFAULT: */
        case PTHREAD_MUTEX_ERRORCHECK:
        case PTHREAD_MUTEX_NORMAL:
                ret = EBUSY;
                break;

        case PTHREAD_MUTEX_RECURSIVE:
                /* Increment the lock count: */
                if (m->m_count + 1 > 0) {
                        m->m_count++;
                        ret = 0;
                } else
                        ret = EAGAIN;
                break;

        default:
                /* Trap invalid mutex types; */
                ret = EINVAL;
        }

        return (ret);
}

static int
mutex_self_lock(pthread_mutex_t m, const struct timespec *abstime)
{
        struct timespec ts1, ts2;
        int ret;

        switch (m->m_type) {
        /* case PTHREAD_MUTEX_DEFAULT: */
        case PTHREAD_MUTEX_ERRORCHECK:
                if (abstime) {
                        clock_gettime(CLOCK_REALTIME, &ts1);
                        timespecsub(abstime, &ts1, &ts2);
                        __sys_nanosleep(&ts2, NULL);
                        ret = ETIMEDOUT;
                } else {
                        /*
                         * POSIX specifies that mutexes should return
                         * EDEADLK if a recursive lock is detected.
                         */
                        ret = EDEADLK;
                }
                break;

        case PTHREAD_MUTEX_NORMAL:
                /*
                 * What SS2 define as a 'normal' mutex.  Intentionally
                 * deadlock on attempts to get a lock you already own.
                 */
                ret = 0;
                if (abstime) {
                        clock_gettime(CLOCK_REALTIME, &ts1);
                        timespecsub(abstime, &ts1, &ts2);
                        __sys_nanosleep(&ts2, NULL);
                        ret = ETIMEDOUT;
                } else {
                        ts1.tv_sec = 30;
                        ts1.tv_nsec = 0;
                        for (;;)
                                __sys_nanosleep(&ts1, NULL);
                }
                break;

        case PTHREAD_MUTEX_RECURSIVE:
                /* Increment the lock count: */
                if (m->m_count + 1 > 0) {
                        m->m_count++;
                        ret = 0;
                } else
                        ret = EAGAIN;
                break;

        default:
                /* Trap invalid mutex types; */
                ret = EINVAL;
        }

        return (ret);
}

static int
mutex_unlock_common(pthread_mutex_t *mutex)
{
        pthread_t curthread = tls_get_curthread();
        pthread_mutex_t m;

        if (__predict_false((m = *mutex) == NULL)) {
                mutex_log2(curthread, m, 252);
                return (EINVAL);
        }
        mutex_log("mutex_unlock_common %p\n", m);
        if (__predict_false(m->m_owner != curthread)) {
                mutex_log("mutex_unlock_common %p (failedA)\n", m);
                mutex_log2(curthread, m, 253);
                return (EPERM);
        }

        if (__predict_false(m->m_type == PTHREAD_MUTEX_RECURSIVE &&
                            m->m_count > 0)) {
                m->m_count--;
                mutex_log("mutex_unlock_common %p (returns 0, partial)\n", m);
                mutex_log2(curthread, m, 254);
        } else {
                /*
                 * Clear the count in case this is a recursive mutex.
                 */
                m->m_count = 0;
                m->m_owner = NULL;
                /* Remove the mutex from the threads queue. */
                MUTEX_ASSERT_IS_OWNED(m);
                TAILQ_REMOVE(&curthread->mutexq, m, m_qe);
                mutex_log2(tls_get_curthread(), m, 35);
                MUTEX_INIT_LINK(m);
                mutex_log2(tls_get_curthread(), m, 36);
                /*
                 * Hand off the mutex to the next waiting thread.
                 */
                mutex_log("mutex_unlock_common %p (returns 0) lock %d\n",
                          m, m->m_lock);
                THR_UMTX_UNLOCK_PERSIST(curthread, &m->m_lock);
                mutex_log2(tls_get_curthread(), m, 37);
                mutex_log2(curthread, m, 255);
        }
        return (0);
}

int
_pthread_mutex_getprioceiling(const pthread_mutex_t * __restrict mutex,
    int * __restrict prioceiling)
{
        if ((mutex == NULL) || (*mutex == NULL))
                return (EINVAL);
        if ((*mutex)->m_protocol != PTHREAD_PRIO_PROTECT)
                return (EINVAL);
        *prioceiling = (*mutex)->m_prio;
        return (0);
}

int
_pthread_mutex_setprioceiling(pthread_mutex_t * __restrict mutex,
    int prioceiling, int * __restrict old_ceiling)
{
        int ret = 0;
        int tmp;

        if ((mutex == NULL) || (*mutex == NULL))
                ret = EINVAL;
        else if ((*mutex)->m_protocol != PTHREAD_PRIO_PROTECT)
                ret = EINVAL;
        else if ((ret = _pthread_mutex_lock(mutex)) == 0) {
                tmp = (*mutex)->m_prio;
                (*mutex)->m_prio = prioceiling;
                ret = _pthread_mutex_unlock(mutex);
                *old_ceiling = tmp;
        }
        return(ret);
}

int
_mutex_cv_lock(pthread_mutex_t *m, int count)
{
        int     ret;

        if ((ret = _pthread_mutex_lock(m)) == 0) {
                (*m)->m_refcount--;
                (*m)->m_count += count;
        }
        return (ret);
}

int
_mutex_cv_unlock(pthread_mutex_t *mutex, int *count)
{
        pthread_t curthread = tls_get_curthread();
        pthread_mutex_t m;

        if (__predict_false(mutex == NULL))
                return (EINVAL);
        if (__predict_false((m = *mutex) == NULL))
                return (EINVAL);
        if (__predict_false(m->m_owner != curthread))
                return (EPERM);

        *count = m->m_count;
        m->m_count = 0;
        m->m_refcount++;
        mutex_log2(tls_get_curthread(), m, 45);
        m->m_owner = NULL;
        /* Remove the mutex from the threads queue. */
        MUTEX_ASSERT_IS_OWNED(m);
        TAILQ_REMOVE(&curthread->mutexq, m, m_qe);
        MUTEX_INIT_LINK(m);
        THR_UMTX_UNLOCK_PERSIST(curthread, &m->m_lock);
        mutex_log2(curthread, m, 250);
        return (0);
}

void
_mutex_unlock_private(pthread_t pthread)
{
        pthread_mutex_t m, m_next;

        for (m = TAILQ_FIRST(&pthread->mutexq); m != NULL; m = m_next) {
                m_next = TAILQ_NEXT(m, m_qe);
                if ((m->m_flags & MUTEX_FLAGS_PRIVATE) != 0)
                        _pthread_mutex_unlock(&m);
        }
}

__strong_reference(__pthread_mutex_init, pthread_mutex_init);
__strong_reference(__pthread_mutex_lock, pthread_mutex_lock);
__strong_reference(__pthread_mutex_timedlock, pthread_mutex_timedlock);
__strong_reference(__pthread_mutex_trylock, pthread_mutex_trylock);

/* Single underscore versions provided for libc internal usage: */
/* No difference between libc and application usage of these: */
__strong_reference(_pthread_mutex_destroy, pthread_mutex_destroy);
__strong_reference(_pthread_mutex_unlock, pthread_mutex_unlock);
__strong_reference(_pthread_mutex_getprioceiling, pthread_mutex_getprioceiling);
__strong_reference(_pthread_mutex_setprioceiling, pthread_mutex_setprioceiling);