/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/* Check that a thread ID returned by H5TS_thread_id() possesses the
 * following properties: 
 *
 * 1 ID >= 1.
 * 2 The ID is constant over the thread's lifetime.
 * 3 No two threads share an ID during their lifetimes.
 * 4 A thread's ID is available for reuse as soon as it is joined.
 */
#include <err.h>

/*
 * Include required headers.  This file tests internal library functions,
 * so we include the private headers here.
 */
#include "testhdf5.h"

#if defined(H5_HAVE_THREADSAFE) && !defined(H5_HAVE_WIN_THREADS)

#define threads_failure(_call, _result) do {                \
    errx(EXIT_FAILURE, "%s.%d: " #_call ": %s", __func__,   \
        __LINE__, strerror(_result));                       \
} while (false)

#define NTHREADS 5

static volatile bool failed = false;
static pthread_barrier_t barrier;
static bool used[NTHREADS];
static pthread_mutex_t used_lock;

static void
atomic_printf(const char *fmt, ...)
{
    char buf[80];
    va_list ap;
    ssize_t nprinted, nwritten;

    va_start(ap, fmt);
    nprinted = vsnprintf(buf, sizeof(buf), fmt, ap);
    va_end(ap);

    if (nprinted == -1)
        err(EXIT_FAILURE, "%s.%d: vsnprintf", __func__, __LINE__);
    else if (nprinted >= (ssize_t)sizeof(buf))
        errx(EXIT_FAILURE, "%s.%d: vsnprintf overflowed", __func__, __LINE__);

    nwritten = write(STDOUT_FILENO, buf, (size_t)nprinted);
    if (nwritten < nprinted) {
        errx(EXIT_FAILURE, "%s.%d: write error or short write",
            __func__, __LINE__);
    }
}

/* Each thread runs this routine.  The routine fetches the current
 * thread's ID, makes sure that it is in the expected range, makes
 * sure that in this round of testing, no two threads shared the
 * same ID, 
 */
static void *
thread_main(void H5_ATTR_UNUSED *arg)
{
    uint64_t ntid, tid;

    tid = H5TS_thread_id();

    if (tid < 1 || NTHREADS < tid) {
        atomic_printf("unexpected tid %" PRIu64 " FAIL\n", tid);
        goto pre_barrier_error;
    }
    pthread_mutex_lock(&used_lock);
    if (used[tid - 1]) {
        atomic_printf("reused tid %" PRIu64 " FAIL\n", tid);
        pthread_mutex_unlock(&used_lock);
        goto pre_barrier_error;
    }
    used[tid - 1] = true;
    pthread_mutex_unlock(&used_lock);

    atomic_printf("tid %" PRIu64 " in [1, %d] PASS\n", tid, NTHREADS);
    pthread_barrier_wait(&barrier);

    ntid = H5TS_thread_id();
    if (ntid != tid) {
        atomic_printf("tid changed from %" PRIu64 " to %" PRIu64 " FAIL\n",
            tid, ntid);
        failed = true;
    }
    return NULL;
pre_barrier_error:
    pthread_barrier_wait(&barrier);
    failed = true;
    return NULL;
}

int
main(void)
{
    int i, rc, times;
    pthread_t threads[NTHREADS];

    /* Run H5open() to initialize the library's thread-ID freelist,
     * mutex, etc.
     */
    if (H5open() != SUCCEED)
        errx(EXIT_FAILURE, "%s.%d: H5open failed", __func__, __LINE__);

    if ((rc = pthread_mutex_init(&used_lock, NULL)) == -1)
        threads_failure(pthread_mutex_init, rc);

    if ((rc = pthread_barrier_init(&barrier, NULL, NTHREADS)) != 0)
        threads_failure(pthread_barrier_init, rc);

    /* Start the test threads and join them twice to make sure that
     * the thread IDs are recycled in the second round.
     */
    for (times = 0; times < 2; times++) {

        for (i = 0; i < NTHREADS; i++)
            used[i] = false;    // access synchronized by thread create/join

        for (i = 0; i < NTHREADS; i++) {
            rc = pthread_create(&threads[i], NULL, thread_main, NULL);
            if (rc != 0)
                threads_failure(pthread_create, rc);
        }

        for (i = 0; i < NTHREADS; i++) {
            rc = pthread_join(threads[i], NULL);
            if (rc != 0)
                threads_failure(pthread_join, rc);
        }

        for (i = 0; i < NTHREADS; i++) {
            if (!used[i]) // access synchronized by thread create/join
                errx(EXIT_FAILURE, "thread ID %d did not run.", i + 1);
        }
    }
    if ((rc = pthread_barrier_destroy(&barrier)) != 0)
        threads_failure(pthread_barrier_destroy, rc);
    return failed ? EXIT_FAILURE : EXIT_SUCCESS;
}

#else /*H5_HAVE_THREADSAFE && !H5_HAVE_WIN_THREADS*/
int
main(void)
{
    errx(EXIT_FAILURE, "not implemented in this configuration.");
}

#endif /*H5_HAVE_THREADSAFE && !H5_HAVE_WIN_THREADS*/