/*-
 * Copyright (c) 2015 Netflix, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/sdt.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/taskqueue.h>
#include <sys/queue.h>
#include <tests/kern_testfrwk.h>
#ifdef SMP
#include <machine/cpu.h>
#endif

struct kern_test_list {
        TAILQ_ENTRY(kern_test_list) next;
        char name[TEST_NAME_LEN];
        kerntfunc func;
};

TAILQ_HEAD(ktestlist, kern_test_list);

struct kern_test_entry {
        TAILQ_ENTRY(kern_test_entry) next;
        struct kern_test_list *kt_e;
        struct kern_test kt_data;
};

TAILQ_HEAD(ktestqueue, kern_test_entry);

MALLOC_DEFINE(M_KTFRWK, "kern_tfrwk", "Kernel Test Framework");
struct kern_totfrwk {
        struct taskqueue *kfrwk_tq;
        struct task kfrwk_que;
        struct ktestlist kfrwk_testlist;
        struct ktestqueue kfrwk_testq;
        struct mtx kfrwk_mtx;
        int kfrwk_waiting;
};

struct kern_totfrwk kfrwk;
static int ktest_frwk_inited = 0;

#define KTFRWK_MUTEX_INIT() mtx_init(&kfrwk.kfrwk_mtx, "kern_test_frwk", "tfrwk", MTX_DEF)

#define KTFRWK_DESTROY() mtx_destroy(&kfrwk.kfrwk_mtx)

#define KTFRWK_LOCK() mtx_lock(&kfrwk.kfrwk_mtx)

#define KTFRWK_UNLOCK() mtx_unlock(&kfrwk.kfrwk_mtx)

static void
kfrwk_task(void *context, int pending)
{
        struct kern_totfrwk *tf;
        struct kern_test_entry *wk;
        int free_mem = 0;
        struct kern_test kt_data;
        kerntfunc ktf;

        memset(&kt_data, 0, sizeof(kt_data));
        ktf = NULL;
        tf = (struct kern_totfrwk *)context;
        KTFRWK_LOCK();
        wk = TAILQ_FIRST(&tf->kfrwk_testq);
        if (wk) {
                wk->kt_data.tot_threads_running--;
                tf->kfrwk_waiting--;
                memcpy(&kt_data, &wk->kt_data, sizeof(kt_data));
                if (wk->kt_data.tot_threads_running == 0) {
                        TAILQ_REMOVE(&tf->kfrwk_testq, wk, next);
                        free_mem = 1;
                } else {
                        /* Wake one of my colleages up to help too */
                        taskqueue_enqueue(tf->kfrwk_tq, &tf->kfrwk_que);
                }
                if (wk->kt_e) {
                        ktf = wk->kt_e->func;
                }
        }
        KTFRWK_UNLOCK();
        if (wk && free_mem) {
                free(wk, M_KTFRWK);
        }
        /* Execute the test */
        if (ktf) {
                (*ktf) (&kt_data);
        }
        /* We are done */
        atomic_add_int(&tf->kfrwk_waiting, 1);
}

static int
kerntest_frwk_init(void)
{
        u_int ncpus = mp_ncpus ? mp_ncpus : MAXCPU;

        KTFRWK_MUTEX_INIT();
        TAILQ_INIT(&kfrwk.kfrwk_testq);
        TAILQ_INIT(&kfrwk.kfrwk_testlist);
        /* Now lets start up a number of tasks to do the work */
        TASK_INIT(&kfrwk.kfrwk_que, 0, kfrwk_task, &kfrwk);
        kfrwk.kfrwk_tq = taskqueue_create_fast("sbtls_task", M_NOWAIT,
            taskqueue_thread_enqueue, &kfrwk.kfrwk_tq);
        if (kfrwk.kfrwk_tq == NULL) {
                printf("Can't start taskqueue for Kernel Test Framework\n");
                panic("Taskqueue init fails for kfrwk");
        }
        taskqueue_start_threads(&kfrwk.kfrwk_tq, ncpus, PI_NET, "[kt_frwk task]");
        kfrwk.kfrwk_waiting = ncpus;
        ktest_frwk_inited = 1;
        return (0);
}

static int
kerntest_frwk_fini(void)
{
        KTFRWK_LOCK();
        if (!TAILQ_EMPTY(&kfrwk.kfrwk_testlist)) {
                /* Still modules registered */
                KTFRWK_UNLOCK();
                return (EBUSY);
        }
        ktest_frwk_inited = 0;
        KTFRWK_UNLOCK();
        taskqueue_free(kfrwk.kfrwk_tq);
        /* Ok lets destroy the mutex on the way outs */
        KTFRWK_DESTROY();
        return (0);
}


static int kerntest_execute(SYSCTL_HANDLER_ARGS);

SYSCTL_NODE(_kern, OID_AUTO, testfrwk, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Kernel Test Framework");
SYSCTL_PROC(_kern_testfrwk, OID_AUTO, runtest,
    CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
    0, 0, kerntest_execute, "IU",
    "Execute a kernel test");

int
kerntest_execute(SYSCTL_HANDLER_ARGS)
{
        struct kern_test kt;
        struct kern_test_list *li, *te = NULL;
        struct kern_test_entry *kte = NULL;
        int error = 0;

        if (ktest_frwk_inited == 0) {
                return (ENOENT);
        }
        /* Find the entry if possible */
        error = SYSCTL_IN(req, &kt, sizeof(struct kern_test));
        if (error) {
                return (error);
        }
        if (kt.num_threads <= 0) {
                return (EINVAL);
        }
        /* Grab some memory */
        kte = malloc(sizeof(struct kern_test_entry), M_KTFRWK, M_WAITOK);
        KTFRWK_LOCK();
        TAILQ_FOREACH(li, &kfrwk.kfrwk_testlist, next) {
                if (strcmp(li->name, kt.name) == 0) {
                        te = li;
                        break;
                }
        }
        if (te == NULL) {
                printf("Can't find the test %s\n", kt.name);
                error = ENOENT;
                free(kte, M_KTFRWK);
                goto out;
        }
        /* Ok we have a test item to run, can we? */
        if (!TAILQ_EMPTY(&kfrwk.kfrwk_testq)) {
                /* We don't know if there is enough threads */
                error = EAGAIN;
                free(kte, M_KTFRWK);
                goto out;
        }
        if (kfrwk.kfrwk_waiting < kt.num_threads) {
                error = E2BIG;
                free(kte, M_KTFRWK);
                goto out;
        }
        kt.tot_threads_running = kt.num_threads;
        /* Ok it looks like we can do it, lets get an entry */
        kte->kt_e = li;
        memcpy(&kte->kt_data, &kt, sizeof(kt));
        TAILQ_INSERT_TAIL(&kfrwk.kfrwk_testq, kte, next);
        taskqueue_enqueue(kfrwk.kfrwk_tq, &kfrwk.kfrwk_que);
out:
        KTFRWK_UNLOCK();
        return (error);
}

int
kern_testframework_register(const char *name, kerntfunc func)
{
        int error = 0;
        struct kern_test_list *li, *te = NULL;
        int len;

        len = strlen(name);
        if (len >= TEST_NAME_LEN) {
                return (E2BIG);
        }
        te = malloc(sizeof(struct kern_test_list), M_KTFRWK, M_WAITOK);
        KTFRWK_LOCK();
        /* First does it already exist? */
        TAILQ_FOREACH(li, &kfrwk.kfrwk_testlist, next) {
                if (strcmp(li->name, name) == 0) {
                        error = EALREADY;
                        free(te, M_KTFRWK);
                        goto out;
                }
        }
        /* Ok we can do it, lets add it to the list */
        te->func = func;
        strcpy(te->name, name);
        TAILQ_INSERT_TAIL(&kfrwk.kfrwk_testlist, te, next);
out:
        KTFRWK_UNLOCK();
        return (error);
}

int
kern_testframework_deregister(const char *name)
{
        struct kern_test_list *li, *te = NULL;
        u_int ncpus = mp_ncpus ? mp_ncpus : MAXCPU;
        int error = 0;

        KTFRWK_LOCK();
        /* First does it already exist? */
        TAILQ_FOREACH(li, &kfrwk.kfrwk_testlist, next) {
                if (strcmp(li->name, name) == 0) {
                        te = li;
                        break;
                }
        }
        if (te == NULL) {
                /* It is not registered so no problem */
                goto out;
        }
        if (ncpus != kfrwk.kfrwk_waiting) {
                /* We are busy executing something -- can't unload */
                error = EBUSY;
                goto out;
        }
        if (!TAILQ_EMPTY(&kfrwk.kfrwk_testq)) {
                /* Something still to execute */
                error = EBUSY;
                goto out;
        }
        /* Ok we can remove the dude safely */
        TAILQ_REMOVE(&kfrwk.kfrwk_testlist, te, next);
        memset(te, 0, sizeof(struct kern_test_list));
        free(te, M_KTFRWK);
out:
        KTFRWK_UNLOCK();
        return (error);
}

static int
kerntest_mod_init(module_t mod, int type, void *data)
{
        int err;

        switch (type) {
        case MOD_LOAD:
                err = kerntest_frwk_init();
                break;
        case MOD_QUIESCE:
                KTFRWK_LOCK();
                if (TAILQ_EMPTY(&kfrwk.kfrwk_testlist)) {
                        err = 0;
                } else {
                        err = EBUSY;
                }
                KTFRWK_UNLOCK();
                break;
        case MOD_UNLOAD:
                err = kerntest_frwk_fini();
                break;
        default:
                return (EOPNOTSUPP);
        }
        return (err);
}

static moduledata_t kern_test_framework = {
        .name = "kernel_testfrwk",
        .evhand = kerntest_mod_init,
        .priv = 0
};

MODULE_VERSION(kern_testframework, 1);
DECLARE_MODULE(kern_testframework, kern_test_framework, SI_SUB_PSEUDO, SI_ORDER_ANY);