/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2022 OmniOS Community Edition (OmniOSce) Association.
 */

#include <atomic.h>
#include <err.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <ucontext.h>
#include <unistd.h>
#include <sys/debug.h>
#include <sys/types.h>

static __thread uint64_t tlsvar;
static ucontext_t ctx;
static uint32_t failures;
static pthread_t tid;

#define THREAD1_VALUE   0x1010
#define THREAD2_VALUE   0x0202

void
report(char *tag)
{
        pthread_t ltid = pthread_self();

        printf("  %-14s: thread=%x, TLS variable=%x\n",
            tag, (uint_t)ltid, tlsvar);
}

void
run(void)
{
        pthread_t ltid = pthread_self();

        printf("Coroutine started from second thread\n");
        report("coroutine");

        if (ltid != tid) {
                fprintf(stderr,
                    "FAIL: coroutine thread ID is %x, expected %x\n",
                    ltid, tid);
                atomic_inc_32(&failures);
        }

        if (tlsvar != THREAD2_VALUE) {
                fprintf(stderr,
                    "FAIL: coroutine TLS variable is %x, expected %x\n",
                    tlsvar, THREAD2_VALUE);
                atomic_inc_32(&failures);
        }
}

void *
thread(void *arg __unused)
{
        tlsvar = THREAD2_VALUE;

        report("second thread");
        /*
         * setcontext() does not return if successful, checking the return
         * value upsets smatch.
         */
        (void) setcontext(&ctx);
        errx(EXIT_FAILURE, "setcontext() returned and should not have.");

        return (NULL);
}

int
main(void)
{
        char stk[SIGSTKSZ];
        void *status;

        tlsvar = THREAD1_VALUE;

        report("main thread");

        VERIFY0(getcontext(&ctx));
        ctx.uc_link = NULL;
        ctx.uc_stack.ss_sp = stk;
        ctx.uc_stack.ss_size = sizeof (stk);
        makecontext(&ctx, run, 0);

        VERIFY0(pthread_create(&tid, NULL, thread, NULL));
        VERIFY0(pthread_join(tid, &status));

        return (failures == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}