// SPDX-License-Identifier: GPL-2.0-or-later
/******************************************************************************
 *
 *   Copyright © International Business Machines  Corp., 2006-2008
 *
 * DESCRIPTION
 *      This test exercises the futex_wait_requeue_pi() signal handling both
 *      before and after the requeue. The first should be restarted by the
 *      kernel. The latter should return EWOULDBLOCK to the waiter.
 *
 * AUTHORS
 *      Darren Hart <dvhart@linux.intel.com>
 *
 * HISTORY
 *      2008-May-5: Initial version by Darren Hart <dvhart@linux.intel.com>
 *
 *****************************************************************************/

#include <errno.h>
#include <getopt.h>
#include <limits.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "atomic.h"
#include "futextest.h"
#include "logging.h"

#define TEST_NAME "futex-requeue-pi-signal-restart"
#define DELAY_US 100

futex_t f1 = FUTEX_INITIALIZER;
futex_t f2 = FUTEX_INITIALIZER;
atomic_t requeued = ATOMIC_INITIALIZER;

int waiter_ret = 0;

void usage(char *prog)
{
        printf("Usage: %s\n", prog);
        printf("  -c    Use color\n");
        printf("  -h    Display this help message\n");
        printf("  -v L  Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
               VQUIET, VCRITICAL, VINFO);
}

int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,
                     int policy, int prio)
{
        struct sched_param schedp;
        pthread_attr_t attr;
        int ret;

        pthread_attr_init(&attr);
        memset(&schedp, 0, sizeof(schedp));

        ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
        if (ret) {
                error("pthread_attr_setinheritsched\n", ret);
                return -1;
        }

        ret = pthread_attr_setschedpolicy(&attr, policy);
        if (ret) {
                error("pthread_attr_setschedpolicy\n", ret);
                return -1;
        }

        schedp.sched_priority = prio;
        ret = pthread_attr_setschedparam(&attr, &schedp);
        if (ret) {
                error("pthread_attr_setschedparam\n", ret);
                return -1;
        }

        ret = pthread_create(pth, &attr, func, arg);
        if (ret) {
                error("pthread_create\n", ret);
                return -1;
        }
        return 0;
}

void handle_signal(int signo)
{
        info("signal received %s requeue\n",
             requeued.val ? "after" : "prior to");
}

void *waiterfn(void *arg)
{
        unsigned int old_val;
        int res;

        waiter_ret = RET_PASS;

        info("Waiter running\n");
        info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
        old_val = f1;
        res = futex_wait_requeue_pi(&f1, old_val, &(f2), NULL,
                                    FUTEX_PRIVATE_FLAG);
        if (!requeued.val || errno != EWOULDBLOCK) {
                fail("unexpected return from futex_wait_requeue_pi: %d (%s)\n",
                     res, strerror(errno));
                info("w2:futex: %x\n", f2);
                if (!res)
                        futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
                waiter_ret = RET_FAIL;
        }

        info("Waiter exiting with %d\n", waiter_ret);
        pthread_exit(NULL);
}


int main(int argc, char *argv[])
{
        unsigned int old_val;
        struct sigaction sa;
        pthread_t waiter;
        int c, res, ret = RET_PASS;

        while ((c = getopt(argc, argv, "chv:")) != -1) {
                switch (c) {
                case 'c':
                        log_color(1);
                        break;
                case 'h':
                        usage(basename(argv[0]));
                        exit(0);
                case 'v':
                        log_verbosity(atoi(optarg));
                        break;
                default:
                        usage(basename(argv[0]));
                        exit(1);
                }
        }

        ksft_print_header();
        ksft_set_plan(1);
        ksft_print_msg("%s: Test signal handling during requeue_pi\n",
               basename(argv[0]));
        ksft_print_msg("\tArguments: <none>\n");

        sa.sa_handler = handle_signal;
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = 0;
        if (sigaction(SIGUSR1, &sa, NULL)) {
                error("sigaction\n", errno);
                exit(1);
        }

        info("m1:f2: %x\n", f2);
        info("Creating waiter\n");
        res = create_rt_thread(&waiter, waiterfn, NULL, SCHED_FIFO, 1);
        if (res) {
                error("Creating waiting thread failed", res);
                ret = RET_ERROR;
                goto out;
        }

        info("Calling FUTEX_LOCK_PI on f2=%x @ %p\n", f2, &f2);
        info("m2:f2: %x\n", f2);
        futex_lock_pi(&f2, 0, 0, FUTEX_PRIVATE_FLAG);
        info("m3:f2: %x\n", f2);

        while (1) {
                /*
                 * signal the waiter before requeue, waiter should automatically
                 * restart futex_wait_requeue_pi() in the kernel. Wait for the
                 * waiter to block on f1 again.
                 */
                info("Issuing SIGUSR1 to waiter\n");
                pthread_kill(waiter, SIGUSR1);
                usleep(DELAY_US);

                info("Requeueing waiter via FUTEX_CMP_REQUEUE_PI\n");
                old_val = f1;
                res = futex_cmp_requeue_pi(&f1, old_val, &(f2), 1, 0,
                                           FUTEX_PRIVATE_FLAG);
                /*
                 * If res is non-zero, we either requeued the waiter or hit an
                 * error, break out and handle it. If it is zero, then the
                 * signal may have hit before the the waiter was blocked on f1.
                 * Try again.
                 */
                if (res > 0) {
                        atomic_set(&requeued, 1);
                        break;
                } else if (res < 0) {
                        error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
                        ret = RET_ERROR;
                        break;
                }
        }
        info("m4:f2: %x\n", f2);

        /*
         * Signal the waiter after requeue, waiter should return from
         * futex_wait_requeue_pi() with EWOULDBLOCK. Join the thread here so the
         * futex_unlock_pi() can't happen before the signal wakeup is detected
         * in the kernel.
         */
        info("Issuing SIGUSR1 to waiter\n");
        pthread_kill(waiter, SIGUSR1);
        info("Waiting for waiter to return\n");
        pthread_join(waiter, NULL);

        info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n", f2, &f2);
        futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
        info("m5:f2: %x\n", f2);

 out:
        if (ret == RET_PASS && waiter_ret)
                ret = waiter_ret;

        print_result(TEST_NAME, ret);
        return ret;
}