root/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
// SPDX-License-Identifier: GPL-2.0

#define _GNU_SOURCE
#include <asm/unistd.h>
#include <linux/time_types.h>
#include <poll.h>
#include <unistd.h>
#include <assert.h>
#include <signal.h>
#include <pthread.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <sys/eventfd.h>
#include "kselftest_harness.h"

struct epoll_mtcontext
{
        int efd[3];
        int sfd[4];
        volatile int count;

        pthread_t main;
        pthread_t waiter;
};

#ifndef __NR_epoll_pwait2
#define __NR_epoll_pwait2 -1
#endif

static inline int sys_epoll_pwait2(int fd, struct epoll_event *events,
                                   int maxevents,
                                   const struct __kernel_timespec *timeout,
                                   const sigset_t *sigset, size_t sigsetsize)
{
        return syscall(__NR_epoll_pwait2, fd, events, maxevents, timeout,
                       sigset, sigsetsize);
}

static void signal_handler(int signum)
{
}

static void kill_timeout(struct epoll_mtcontext *ctx)
{
        usleep(1000000);
        pthread_kill(ctx->main, SIGUSR1);
        pthread_kill(ctx->waiter, SIGUSR1);
}

static void *waiter_entry1a(void *data)
{
        struct epoll_event e;
        struct epoll_mtcontext *ctx = data;

        if (epoll_wait(ctx->efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx->count, 1);

        return NULL;
}

static void *waiter_entry1ap(void *data)
{
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext *ctx = data;

        pfd.fd = ctx->efd[0];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx->efd[0], &e, 1, 0) > 0)
                        __sync_fetch_and_add(&ctx->count, 1);
        }

        return NULL;
}

static void *waiter_entry1o(void *data)
{
        struct epoll_event e;
        struct epoll_mtcontext *ctx = data;

        if (epoll_wait(ctx->efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_or(&ctx->count, 1);

        return NULL;
}

static void *waiter_entry1op(void *data)
{
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext *ctx = data;

        pfd.fd = ctx->efd[0];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx->efd[0], &e, 1, 0) > 0)
                        __sync_fetch_and_or(&ctx->count, 1);
        }

        return NULL;
}

static void *waiter_entry2a(void *data)
{
        struct epoll_event events[2];
        struct epoll_mtcontext *ctx = data;

        if (epoll_wait(ctx->efd[0], events, 2, -1) > 0)
                __sync_fetch_and_add(&ctx->count, 1);

        return NULL;
}

static void *waiter_entry2ap(void *data)
{
        struct pollfd pfd;
        struct epoll_event events[2];
        struct epoll_mtcontext *ctx = data;

        pfd.fd = ctx->efd[0];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx->efd[0], events, 2, 0) > 0)
                        __sync_fetch_and_add(&ctx->count, 1);
        }

        return NULL;
}

static void *emitter_entry1(void *data)
{
        struct epoll_mtcontext *ctx = data;

        usleep(100000);
        write(ctx->sfd[1], "w", 1);

        kill_timeout(ctx);

        return NULL;
}

static void *emitter_entry2(void *data)
{
        struct epoll_mtcontext *ctx = data;

        usleep(100000);
        write(ctx->sfd[1], "w", 1);
        write(ctx->sfd[3], "w", 1);

        kill_timeout(ctx);

        return NULL;
}

/*
 *          t0
 *           | (ew)
 *          e0
 *           | (lt)
 *          s0
 */
TEST(epoll1)
{
        int efd;
        int sfd[2];
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd, &e, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd, &e, 1, 0), 1);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *          t0
 *           | (ew)
 *          e0
 *           | (et)
 *          s0
 */
TEST(epoll2)
{
        int efd;
        int sfd[2];
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd, &e, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd, &e, 1, 0), 0);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *           t0
 *            | (ew)
 *           e0
 *     (lt) /  \ (lt)
 *        s0    s2
 */
TEST(epoll3)
{
        int efd;
        int sfd[4];
        struct epoll_event events[2];

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[2]), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[2], events), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);
        ASSERT_EQ(write(sfd[3], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd, events, 2, 0), 2);
        EXPECT_EQ(epoll_wait(efd, events, 2, 0), 2);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
        close(sfd[2]);
        close(sfd[3]);
}

/*
 *           t0
 *            | (ew)
 *           e0
 *     (et) /  \ (et)
 *        s0    s2
 */
TEST(epoll4)
{
        int efd;
        int sfd[4];
        struct epoll_event events[2];

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[2]), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], events), 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[2], events), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);
        ASSERT_EQ(write(sfd[3], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd, events, 2, 0), 2);
        EXPECT_EQ(epoll_wait(efd, events, 2, 0), 0);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
        close(sfd[2]);
        close(sfd[3]);
}

/*
 *          t0
 *           | (p)
 *          e0
 *           | (lt)
 *          s0
 */
TEST(epoll5)
{
        int efd;
        int sfd[2];
        struct pollfd pfd;
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        pfd.fd = efd;
        pfd.events = POLLIN;
        ASSERT_EQ(poll(&pfd, 1, 0), 1);
        ASSERT_EQ(epoll_wait(efd, &e, 1, 0), 1);

        pfd.fd = efd;
        pfd.events = POLLIN;
        ASSERT_EQ(poll(&pfd, 1, 0), 1);
        ASSERT_EQ(epoll_wait(efd, &e, 1, 0), 1);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *          t0
 *           | (p)
 *          e0
 *           | (et)
 *          s0
 */
TEST(epoll6)
{
        int efd;
        int sfd[2];
        struct pollfd pfd;
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        pfd.fd = efd;
        pfd.events = POLLIN;
        ASSERT_EQ(poll(&pfd, 1, 0), 1);
        ASSERT_EQ(epoll_wait(efd, &e, 1, 0), 1);

        pfd.fd = efd;
        pfd.events = POLLIN;
        ASSERT_EQ(poll(&pfd, 1, 0), 0);
        ASSERT_EQ(epoll_wait(efd, &e, 1, 0), 0);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *           t0
 *            | (p)
 *           e0
 *     (lt) /  \ (lt)
 *        s0    s2
 */

TEST(epoll7)
{
        int efd;
        int sfd[4];
        struct pollfd pfd;
        struct epoll_event events[2];

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[2]), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[2], events), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);
        ASSERT_EQ(write(sfd[3], "w", 1), 1);

        pfd.fd = efd;
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd, events, 2, 0), 2);

        pfd.fd = efd;
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd, events, 2, 0), 2);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
        close(sfd[2]);
        close(sfd[3]);
}

/*
 *           t0
 *            | (p)
 *           e0
 *     (et) /  \ (et)
 *        s0    s2
 */
TEST(epoll8)
{
        int efd;
        int sfd[4];
        struct pollfd pfd;
        struct epoll_event events[2];

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[2]), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], events), 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[2], events), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);
        ASSERT_EQ(write(sfd[3], "w", 1), 1);

        pfd.fd = efd;
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd, events, 2, 0), 2);

        pfd.fd = efd;
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 0);
        EXPECT_EQ(epoll_wait(efd, events, 2, 0), 0);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
        close(sfd[2]);
        close(sfd[3]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *            | (lt)
 *           s0
 */
TEST(epoll9)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *            | (et)
 *           s0
 */
TEST(epoll10)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 1);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *     (lt) /  \ (lt)
 *        s0    s2
 */
TEST(epoll11)
{
        pthread_t emitter;
        struct epoll_event events[2];
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[2], events), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry2a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        if (epoll_wait(ctx.efd[0], events, 2, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *     (et) /  \ (et)
 *        s0    s2
 */
TEST(epoll12)
{
        pthread_t emitter;
        struct epoll_event events[2];
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], events), 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[2], events), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        if (epoll_wait(ctx.efd[0], events, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *            | (lt)
 *           s0
 */
TEST(epoll13)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *            | (et)
 *           s0
 */
TEST(epoll14)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 1);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *     (lt) /  \ (lt)
 *        s0    s2
 */
TEST(epoll15)
{
        pthread_t emitter;
        struct epoll_event events[2];
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[2], events), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry2ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        if (epoll_wait(ctx.efd[0], events, 2, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *     (et) /  \ (et)
 *        s0    s2
 */
TEST(epoll16)
{
        pthread_t emitter;
        struct epoll_event events[2];
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], events), 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[2], events), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        if (epoll_wait(ctx.efd[0], events, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *          t0
 *           | (ew)
 *          e0
 *           | (lt)
 *          e1
 *           | (lt)
 *          s0
 */
TEST(epoll17)
{
        int efd[2];
        int sfd[2];
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);

        close(efd[0]);
        close(efd[1]);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *          t0
 *           | (ew)
 *          e0
 *           | (lt)
 *          e1
 *           | (et)
 *          s0
 */
TEST(epoll18)
{
        int efd[2];
        int sfd[2];
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);

        close(efd[0]);
        close(efd[1]);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *           t0
 *            | (ew)
 *           e0
 *            | (et)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll19)
{
        int efd[2];
        int sfd[2];
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 0);

        close(efd[0]);
        close(efd[1]);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *           t0
 *            | (ew)
 *           e0
 *            | (et)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll20)
{
        int efd[2];
        int sfd[2];
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 0);

        close(efd[0]);
        close(efd[1]);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *          t0
 *           | (p)
 *          e0
 *           | (lt)
 *          e1
 *           | (lt)
 *          s0
 */
TEST(epoll21)
{
        int efd[2];
        int sfd[2];
        struct pollfd pfd;
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);

        close(efd[0]);
        close(efd[1]);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *          t0
 *           | (p)
 *          e0
 *           | (lt)
 *          e1
 *           | (et)
 *          s0
 */
TEST(epoll22)
{
        int efd[2];
        int sfd[2];
        struct pollfd pfd;
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);

        close(efd[0]);
        close(efd[1]);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *          t0
 *           | (p)
 *          e0
 *           | (et)
 *          e1
 *           | (lt)
 *          s0
 */
TEST(epoll23)
{
        int efd[2];
        int sfd[2];
        struct pollfd pfd;
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 0);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 0);

        close(efd[0]);
        close(efd[1]);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *          t0
 *           | (p)
 *          e0
 *           | (et)
 *          e1
 *           | (et)
 *          s0
 */
TEST(epoll24)
{
        int efd[2];
        int sfd[2];
        struct pollfd pfd;
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 0);
        EXPECT_EQ(epoll_wait(efd[0], &e, 1, 0), 0);

        close(efd[0]);
        close(efd[1]);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *            | (lt)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll25)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *            | (lt)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll26)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *            | (et)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll27)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 1);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *            | (et)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll28)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 1);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *            | (lt)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll29)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *            | (lt)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll30)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *            | (et)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll31)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 1);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *            | (et)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll32)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 1);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *    (ew) |    | (ew)
 *         |   e0
 *          \  / (lt)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll33)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *    (ew) |    | (ew)
 *         |   e0
 *          \  / (lt)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll34)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1o, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_or(&ctx.count, 2);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_TRUE((ctx.count == 2) || (ctx.count == 3));

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *    (ew) |    | (ew)
 *         |   e0
 *          \  / (et)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll35)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *    (ew) |    | (ew)
 *         |   e0
 *          \  / (et)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll36)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1o, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_or(&ctx.count, 2);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_TRUE((ctx.count == 2) || (ctx.count == 3));

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *     (p) |    | (ew)
 *         |   e0
 *          \  / (lt)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll37)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        pfd.fd = ctx.efd[1];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx.efd[1], &e, 1, 0) > 0)
                        __sync_fetch_and_add(&ctx.count, 1);
        }

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *     (p) |    | (ew)
 *         |   e0
 *          \  / (lt)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll38)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1o, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        pfd.fd = ctx.efd[1];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx.efd[1], &e, 1, 0) > 0)
                        __sync_fetch_and_or(&ctx.count, 2);
        }

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_TRUE((ctx.count == 2) || (ctx.count == 3));

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *     (p) |    | (ew)
 *         |   e0
 *          \  / (et)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll39)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        pfd.fd = ctx.efd[1];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx.efd[1], &e, 1, 0) > 0)
                        __sync_fetch_and_add(&ctx.count, 1);
        }

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *     (p) |    | (ew)
 *         |   e0
 *          \  / (et)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll40)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1o, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        pfd.fd = ctx.efd[1];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx.efd[1], &e, 1, 0) > 0)
                        __sync_fetch_and_or(&ctx.count, 2);
        }

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_TRUE((ctx.count == 2) || (ctx.count == 3));

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *    (ew) |    | (p)
 *         |   e0
 *          \  / (lt)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll41)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *    (ew) |    | (p)
 *         |   e0
 *          \  / (lt)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll42)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1op, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_or(&ctx.count, 2);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_TRUE((ctx.count == 2) || (ctx.count == 3));

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *    (ew) |    | (p)
 *         |   e0
 *          \  / (et)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll43)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *    (ew) |    | (p)
 *         |   e0
 *          \  / (et)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll44)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1op, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_or(&ctx.count, 2);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_TRUE((ctx.count == 2) || (ctx.count == 3));

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *     (p) |    | (p)
 *         |   e0
 *          \  / (lt)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll45)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        pfd.fd = ctx.efd[1];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx.efd[1], &e, 1, 0) > 0)
                        __sync_fetch_and_add(&ctx.count, 1);
        }

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *     (p) |    | (p)
 *         |   e0
 *          \  / (lt)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll46)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1op, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_or(&ctx.count, 2);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_TRUE((ctx.count == 2) || (ctx.count == 3));

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *     (p) |    | (p)
 *         |   e0
 *          \  / (et)
 *           e1
 *            | (lt)
 *           s0
 */
TEST(epoll47)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        pfd.fd = ctx.efd[1];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx.efd[1], &e, 1, 0) > 0)
                        __sync_fetch_and_add(&ctx.count, 1);
        }

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *        t0   t1
 *     (p) |    | (p)
 *         |   e0
 *          \  / (et)
 *           e1
 *            | (et)
 *           s0
 */
TEST(epoll48)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1op, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry1, &ctx), 0);

        if (epoll_wait(ctx.efd[1], &e, 1, -1) > 0)
                __sync_fetch_and_or(&ctx.count, 2);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_TRUE((ctx.count == 2) || (ctx.count == 3));

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

/*
 *           t0
 *            | (ew)
 *           e0
 *     (lt) /  \ (lt)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll49)
{
        int efd[3];
        int sfd[4];
        struct epoll_event events[2];

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[2]), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        efd[2] = epoll_create(1);
        ASSERT_GE(efd[2], 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[2], EPOLL_CTL_ADD, sfd[2], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[2], events), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);
        ASSERT_EQ(write(sfd[3], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd[0], events, 2, 0), 2);
        EXPECT_EQ(epoll_wait(efd[0], events, 2, 0), 2);

        close(efd[0]);
        close(efd[1]);
        close(efd[2]);
        close(sfd[0]);
        close(sfd[1]);
        close(sfd[2]);
        close(sfd[3]);
}

/*
 *           t0
 *            | (ew)
 *           e0
 *     (et) /  \ (et)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll50)
{
        int efd[3];
        int sfd[4];
        struct epoll_event events[2];

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[2]), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        efd[2] = epoll_create(1);
        ASSERT_GE(efd[2], 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[2], EPOLL_CTL_ADD, sfd[2], events), 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], events), 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[2], events), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);
        ASSERT_EQ(write(sfd[3], "w", 1), 1);

        EXPECT_EQ(epoll_wait(efd[0], events, 2, 0), 2);
        EXPECT_EQ(epoll_wait(efd[0], events, 2, 0), 0);

        close(efd[0]);
        close(efd[1]);
        close(efd[2]);
        close(sfd[0]);
        close(sfd[1]);
        close(sfd[2]);
        close(sfd[3]);
}

/*
 *           t0
 *            | (p)
 *           e0
 *     (lt) /  \ (lt)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll51)
{
        int efd[3];
        int sfd[4];
        struct pollfd pfd;
        struct epoll_event events[2];

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[2]), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        efd[2] = epoll_create(1);
        ASSERT_GE(efd[2], 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[2], EPOLL_CTL_ADD, sfd[2], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[2], events), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);
        ASSERT_EQ(write(sfd[3], "w", 1), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], events, 2, 0), 2);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], events, 2, 0), 2);

        close(efd[0]);
        close(efd[1]);
        close(efd[2]);
        close(sfd[0]);
        close(sfd[1]);
        close(sfd[2]);
        close(sfd[3]);
}

/*
 *           t0
 *            | (p)
 *           e0
 *     (et) /  \ (et)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll52)
{
        int efd[3];
        int sfd[4];
        struct pollfd pfd;
        struct epoll_event events[2];

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &sfd[2]), 0);

        efd[0] = epoll_create(1);
        ASSERT_GE(efd[0], 0);

        efd[1] = epoll_create(1);
        ASSERT_GE(efd[1], 0);

        efd[2] = epoll_create(1);
        ASSERT_GE(efd[2], 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[1], EPOLL_CTL_ADD, sfd[0], events), 0);

        events[0].events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd[2], EPOLL_CTL_ADD, sfd[2], events), 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[1], events), 0);

        events[0].events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(efd[0], EPOLL_CTL_ADD, efd[2], events), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);
        ASSERT_EQ(write(sfd[3], "w", 1), 1);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 1);
        EXPECT_EQ(epoll_wait(efd[0], events, 2, 0), 2);

        pfd.fd = efd[0];
        pfd.events = POLLIN;
        EXPECT_EQ(poll(&pfd, 1, 0), 0);
        EXPECT_EQ(epoll_wait(efd[0], events, 2, 0), 0);

        close(efd[0]);
        close(efd[1]);
        close(efd[2]);
        close(sfd[0]);
        close(sfd[1]);
        close(sfd[2]);
        close(sfd[3]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *     (lt) /  \ (lt)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll53)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        ctx.efd[2] = epoll_create(1);
        ASSERT_GE(ctx.efd[2], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[2], EPOLL_CTL_ADD, ctx.sfd[2], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[2], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.efd[2]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *     (et) /  \ (et)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll54)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        ctx.efd[2] = epoll_create(1);
        ASSERT_GE(ctx.efd[2], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[2], EPOLL_CTL_ADD, ctx.sfd[2], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[2], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.efd[2]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *     (lt) /  \ (lt)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll55)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        ctx.efd[2] = epoll_create(1);
        ASSERT_GE(ctx.efd[2], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[2], EPOLL_CTL_ADD, ctx.sfd[2], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[2], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.efd[2]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *        t0    t1
 *     (ew) \  / (p)
 *           e0
 *     (et) /  \ (et)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll56)
{
        pthread_t emitter;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        ctx.efd[2] = epoll_create(1);
        ASSERT_GE(ctx.efd[2], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[2], EPOLL_CTL_ADD, ctx.sfd[2], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[2], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        if (epoll_wait(ctx.efd[0], &e, 1, -1) > 0)
                __sync_fetch_and_add(&ctx.count, 1);

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.efd[2]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *        t0    t1
 *      (p) \  / (p)
 *           e0
 *     (lt) /  \ (lt)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll57)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        ctx.efd[2] = epoll_create(1);
        ASSERT_GE(ctx.efd[2], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[2], EPOLL_CTL_ADD, ctx.sfd[2], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[2], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        pfd.fd = ctx.efd[0];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx.efd[0], &e, 1, 0) > 0)
                        __sync_fetch_and_add(&ctx.count, 1);
        }

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.efd[2]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

/*
 *        t0    t1
 *      (p) \  / (p)
 *           e0
 *     (et) /  \ (et)
 *        e1    e2
 *    (lt) |     | (lt)
 *        s0    s2
 */
TEST(epoll58)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[0]), 0);
        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx.sfd[2]), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.efd[1] = epoll_create(1);
        ASSERT_GE(ctx.efd[1], 0);

        ctx.efd[2] = epoll_create(1);
        ASSERT_GE(ctx.efd[2], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[1], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[2], EPOLL_CTL_ADD, ctx.sfd[2], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[1], &e), 0);

        e.events = EPOLLIN | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.efd[2], &e), 0);

        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&ctx.waiter, NULL, waiter_entry1ap, &ctx), 0);
        ASSERT_EQ(pthread_create(&emitter, NULL, emitter_entry2, &ctx), 0);

        pfd.fd = ctx.efd[0];
        pfd.events = POLLIN;
        if (poll(&pfd, 1, -1) > 0) {
                if (epoll_wait(ctx.efd[0], &e, 1, 0) > 0)
                        __sync_fetch_and_add(&ctx.count, 1);
        }

        ASSERT_EQ(pthread_join(ctx.waiter, NULL), 0);
        EXPECT_EQ(ctx.count, 2);

        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }

        close(ctx.efd[0]);
        close(ctx.efd[1]);
        close(ctx.efd[2]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
        close(ctx.sfd[2]);
        close(ctx.sfd[3]);
}

static void *epoll59_thread(void *ctx_)
{
        struct epoll_mtcontext *ctx = ctx_;
        struct epoll_event e;
        int i;

        for (i = 0; i < 100000; i++) {
                while (ctx->count == 0)
                        ;

                e.events = EPOLLIN | EPOLLERR | EPOLLET;
                epoll_ctl(ctx->efd[0], EPOLL_CTL_MOD, ctx->sfd[0], &e);
                ctx->count = 0;
        }

        return NULL;
}

/*
 *        t0
 *      (p) \
 *           e0
 *     (et) /
 *        e0
 *
 * Based on https://bugzilla.kernel.org/show_bug.cgi?id=205933
 */
TEST(epoll59)
{
        pthread_t emitter;
        struct pollfd pfd;
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };
        int i, ret;

        signal(SIGUSR1, signal_handler);

        ctx.efd[0] = epoll_create1(0);
        ASSERT_GE(ctx.efd[0], 0);

        ctx.sfd[0] = eventfd(1, 0);
        ASSERT_GE(ctx.sfd[0], 0);

        e.events = EPOLLIN | EPOLLERR | EPOLLET;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        ASSERT_EQ(pthread_create(&emitter, NULL, epoll59_thread, &ctx), 0);

        for (i = 0; i < 100000; i++) {
                ret = epoll_wait(ctx.efd[0], &e, 1, 1000);
                ASSERT_GT(ret, 0);

                while (ctx.count != 0)
                        ;
                ctx.count = 1;
        }
        if (pthread_tryjoin_np(emitter, NULL) < 0) {
                pthread_kill(emitter, SIGUSR1);
                pthread_join(emitter, NULL);
        }
        close(ctx.efd[0]);
        close(ctx.sfd[0]);
}

enum {
        EPOLL60_EVENTS_NR = 10,
};

struct epoll60_ctx {
        volatile int stopped;
        int ready;
        int waiters;
        int epfd;
        int evfd[EPOLL60_EVENTS_NR];
};

static void *epoll60_wait_thread(void *ctx_)
{
        struct epoll60_ctx *ctx = ctx_;
        struct epoll_event e;
        sigset_t sigmask;
        uint64_t v;
        int ret;

        /* Block SIGUSR1 */
        sigemptyset(&sigmask);
        sigaddset(&sigmask, SIGUSR1);
        sigprocmask(SIG_SETMASK, &sigmask, NULL);

        /* Prepare empty mask for epoll_pwait() */
        sigemptyset(&sigmask);

        while (!ctx->stopped) {
                /* Mark we are ready */
                __atomic_fetch_add(&ctx->ready, 1, __ATOMIC_ACQUIRE);

                /* Start when all are ready */
                while (__atomic_load_n(&ctx->ready, __ATOMIC_ACQUIRE) &&
                       !ctx->stopped);

                /* Account this waiter */
                __atomic_fetch_add(&ctx->waiters, 1, __ATOMIC_ACQUIRE);

                ret = epoll_pwait(ctx->epfd, &e, 1, 2000, &sigmask);
                if (ret != 1) {
                        /* We expect only signal delivery on stop */
                        assert(ret < 0 && errno == EINTR && "Lost wakeup!\n");
                        assert(ctx->stopped);
                        break;
                }

                ret = read(e.data.fd, &v, sizeof(v));
                /* Since we are on ET mode, thus each thread gets its own fd. */
                assert(ret == sizeof(v));

                __atomic_fetch_sub(&ctx->waiters, 1, __ATOMIC_RELEASE);
        }

        return NULL;
}

static inline unsigned long long msecs(void)
{
        struct timespec ts;
        unsigned long long msecs;

        clock_gettime(CLOCK_REALTIME, &ts);
        msecs = ts.tv_sec * 1000ull;
        msecs += ts.tv_nsec / 1000000ull;

        return msecs;
}

static inline int count_waiters(struct epoll60_ctx *ctx)
{
        return __atomic_load_n(&ctx->waiters, __ATOMIC_ACQUIRE);
}

TEST(epoll60)
{
        struct epoll60_ctx ctx = { 0 };
        pthread_t waiters[ARRAY_SIZE(ctx.evfd)];
        struct epoll_event e;
        int i, n, ret;

        signal(SIGUSR1, signal_handler);

        ctx.epfd = epoll_create1(0);
        ASSERT_GE(ctx.epfd, 0);

        /* Create event fds */
        for (i = 0; i < ARRAY_SIZE(ctx.evfd); i++) {
                ctx.evfd[i] = eventfd(0, EFD_NONBLOCK);
                ASSERT_GE(ctx.evfd[i], 0);

                e.events = EPOLLIN | EPOLLET;
                e.data.fd = ctx.evfd[i];
                ASSERT_EQ(epoll_ctl(ctx.epfd, EPOLL_CTL_ADD, ctx.evfd[i], &e), 0);
        }

        /* Create waiter threads */
        for (i = 0; i < ARRAY_SIZE(waiters); i++)
                ASSERT_EQ(pthread_create(&waiters[i], NULL,
                                         epoll60_wait_thread, &ctx), 0);

        for (i = 0; i < 300; i++) {
                uint64_t v = 1, ms;

                /* Wait for all to be ready */
                while (__atomic_load_n(&ctx.ready, __ATOMIC_ACQUIRE) !=
                       ARRAY_SIZE(ctx.evfd))
                        ;

                /* Steady, go */
                __atomic_fetch_sub(&ctx.ready, ARRAY_SIZE(ctx.evfd),
                                   __ATOMIC_ACQUIRE);

                /* Wait all have gone to kernel */
                while (count_waiters(&ctx) != ARRAY_SIZE(ctx.evfd))
                        ;

                /* 1ms should be enough to schedule away */
                usleep(1000);

                /* Quickly signal all handles at once */
                for (n = 0; n < ARRAY_SIZE(ctx.evfd); n++) {
                        ret = write(ctx.evfd[n], &v, sizeof(v));
                        ASSERT_EQ(ret, sizeof(v));
                }

                /* Busy loop for 1s and wait for all waiters to wake up */
                ms = msecs();
                while (count_waiters(&ctx) && msecs() < ms + 1000)
                        ;

                ASSERT_EQ(count_waiters(&ctx), 0);
        }
        ctx.stopped = 1;
        /* Stop waiters */
        for (i = 0; i < ARRAY_SIZE(waiters); i++)
                ret = pthread_kill(waiters[i], SIGUSR1);
        for (i = 0; i < ARRAY_SIZE(waiters); i++)
                pthread_join(waiters[i], NULL);

        for (i = 0; i < ARRAY_SIZE(waiters); i++)
                close(ctx.evfd[i]);
        close(ctx.epfd);
}

struct epoll61_ctx {
        int epfd;
        int evfd;
};

static void *epoll61_write_eventfd(void *ctx_)
{
        struct epoll61_ctx *ctx = ctx_;
        int64_t l = 1;

        usleep(10950);
        write(ctx->evfd, &l, sizeof(l));
        return NULL;
}

static void *epoll61_epoll_with_timeout(void *ctx_)
{
        struct epoll61_ctx *ctx = ctx_;
        struct epoll_event events[1];
        int n;

        n = epoll_wait(ctx->epfd, events, 1, 11);
        /*
         * If epoll returned the eventfd, write on the eventfd to wake up the
         * blocking poller.
         */
        if (n == 1) {
                int64_t l = 1;

                write(ctx->evfd, &l, sizeof(l));
        }
        return NULL;
}

static void *epoll61_blocking_epoll(void *ctx_)
{
        struct epoll61_ctx *ctx = ctx_;
        struct epoll_event events[1];

        epoll_wait(ctx->epfd, events, 1, -1);
        return NULL;
}

TEST(epoll61)
{
        struct epoll61_ctx ctx;
        struct epoll_event ev;
        int i, r;

        ctx.epfd = epoll_create1(0);
        ASSERT_GE(ctx.epfd, 0);
        ctx.evfd = eventfd(0, EFD_NONBLOCK);
        ASSERT_GE(ctx.evfd, 0);

        ev.events = EPOLLIN | EPOLLET | EPOLLERR | EPOLLHUP;
        ev.data.ptr = NULL;
        r = epoll_ctl(ctx.epfd, EPOLL_CTL_ADD, ctx.evfd, &ev);
        ASSERT_EQ(r, 0);

        /*
         * We are testing a race.  Repeat the test case 1000 times to make it
         * more likely to fail in case of a bug.
         */
        for (i = 0; i < 1000; i++) {
                pthread_t threads[3];
                int n;

                /*
                 * Start 3 threads:
                 * Thread 1 sleeps for 10.9ms and writes to the evenfd.
                 * Thread 2 calls epoll with a timeout of 11ms.
                 * Thread 3 calls epoll with a timeout of -1.
                 *
                 * The eventfd write by Thread 1 should either wakeup Thread 2
                 * or Thread 3.  If it wakes up Thread 2, Thread 2 writes on the
                 * eventfd to wake up Thread 3.
                 *
                 * If no events are missed, all three threads should eventually
                 * be joinable.
                 */
                ASSERT_EQ(pthread_create(&threads[0], NULL,
                                         epoll61_write_eventfd, &ctx), 0);
                ASSERT_EQ(pthread_create(&threads[1], NULL,
                                         epoll61_epoll_with_timeout, &ctx), 0);
                ASSERT_EQ(pthread_create(&threads[2], NULL,
                                         epoll61_blocking_epoll, &ctx), 0);

                for (n = 0; n < ARRAY_SIZE(threads); ++n)
                        ASSERT_EQ(pthread_join(threads[n], NULL), 0);
        }

        close(ctx.epfd);
        close(ctx.evfd);
}

/* Equivalent to basic test epoll1, but exercising epoll_pwait2. */
TEST(epoll62)
{
        int efd;
        int sfd[2];
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], &e), 0);

        ASSERT_EQ(write(sfd[1], "w", 1), 1);

        EXPECT_EQ(sys_epoll_pwait2(efd, &e, 1, NULL, NULL, 0), 1);
        EXPECT_EQ(sys_epoll_pwait2(efd, &e, 1, NULL, NULL, 0), 1);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
}

/* Epoll_pwait2 basic timeout test. */
TEST(epoll63)
{
        const int cfg_delay_ms = 10;
        unsigned long long tdiff;
        struct __kernel_timespec ts;
        int efd;
        int sfd[2];
        struct epoll_event e;

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);

        efd = epoll_create(1);
        ASSERT_GE(efd, 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], &e), 0);

        ts.tv_sec = 0;
        ts.tv_nsec = cfg_delay_ms * 1000 * 1000;

        tdiff = msecs();
        EXPECT_EQ(sys_epoll_pwait2(efd, &e, 1, &ts, NULL, 0), 0);
        tdiff = msecs() - tdiff;

        EXPECT_GE(tdiff, cfg_delay_ms);

        close(efd);
        close(sfd[0]);
        close(sfd[1]);
}

/*
 *        t0    t1
 *     (ew) \  / (ew)
 *           e0
 *            | (lt)
 *           s0
 */
TEST(epoll64)
{
        pthread_t waiter[2];
        struct epoll_event e;
        struct epoll_mtcontext ctx = { 0 };

        signal(SIGUSR1, signal_handler);

        ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);

        ctx.efd[0] = epoll_create(1);
        ASSERT_GE(ctx.efd[0], 0);

        e.events = EPOLLIN;
        ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);

        /*
         * main will act as the emitter once both waiter threads are
         * blocked and expects to both be awoken upon the ready event.
         */
        ctx.main = pthread_self();
        ASSERT_EQ(pthread_create(&waiter[0], NULL, waiter_entry1a, &ctx), 0);
        ASSERT_EQ(pthread_create(&waiter[1], NULL, waiter_entry1a, &ctx), 0);

        usleep(100000);
        ASSERT_EQ(write(ctx.sfd[1], "w", 1), 1);

        ASSERT_EQ(pthread_join(waiter[0], NULL), 0);
        ASSERT_EQ(pthread_join(waiter[1], NULL), 0);

        EXPECT_EQ(ctx.count, 2);

        close(ctx.efd[0]);
        close(ctx.sfd[0]);
        close(ctx.sfd[1]);
}

TEST_HARNESS_MAIN