/*

 * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/*

 * Without this we start getting longjmp crashes because it thinks we're jumping

 * up the stack when in fact we are jumping to an entirely different stack. The

 * cost of this is not having certain buffer overrun/underrun checks etc for

 * this source file :-(

 */

#undef _FORTIFY_SOURCE

/* This must be the first #include file */

#include "async_local.h"

#include <openssl/err.h>

#include "crypto/cryptlib.h"

#include <string.h>

#define ASYNC_JOB_RUNNING   0

#define ASYNC_JOB_PAUSING   1

#define ASYNC_JOB_PAUSED    2

#define ASYNC_JOB_STOPPING  3

static CRYPTO_THREAD_LOCAL ctxkey;

static CRYPTO_THREAD_LOCAL poolkey;

static async_ctx *async_ctx_new(void)

{

    async_ctx *nctx;

    if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_ASYNC))

        return NULL;

    nctx = OPENSSL_malloc(sizeof(*nctx));

    if (nctx == NULL) {

        ASYNCerr(ASYNC_F_ASYNC_CTX_NEW, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    async_fibre_init_dispatcher(&nctx->dispatcher);

    nctx->currjob = NULL;

    nctx->blocked = 0;

    if (!CRYPTO_THREAD_set_local(&ctxkey, nctx))

        goto err;

    return nctx;

err:

    OPENSSL_free(nctx);

    return NULL;

}

async_ctx *async_get_ctx(void)

{

    return (async_ctx *)CRYPTO_THREAD_get_local(&ctxkey);

}

static int async_ctx_free(void)

{

    async_ctx *ctx;

    ctx = async_get_ctx();

    if (!CRYPTO_THREAD_set_local(&ctxkey, NULL))

        return 0;

    OPENSSL_free(ctx);

    return 1;

}

static ASYNC_JOB *async_job_new(void)

{

    ASYNC_JOB *job = NULL;

    job = OPENSSL_zalloc(sizeof(*job));

    if (job == NULL) {

        ASYNCerr(ASYNC_F_ASYNC_JOB_NEW, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    job->status = ASYNC_JOB_RUNNING;

    return job;

}

static void async_job_free(ASYNC_JOB *job)

{

    if (job != NULL) {

        OPENSSL_free(job->funcargs);

        async_fibre_free(&job->fibrectx);

        OPENSSL_free(job);

    }

}

static ASYNC_JOB *async_get_pool_job(void) {

    ASYNC_JOB *job;

    async_pool *pool;

    pool = (async_pool *)CRYPTO_THREAD_get_local(&poolkey);

    if (pool == NULL) {

        /*

         * Pool has not been initialised, so init with the defaults, i.e.

         * no max size and no pre-created jobs

         */

        if (ASYNC_init_thread(0, 0) == 0)

            return NULL;

        pool = (async_pool *)CRYPTO_THREAD_get_local(&poolkey);

    }

    job = sk_ASYNC_JOB_pop(pool->jobs);

    if (job == NULL) {

        /* Pool is empty */

        if ((pool->max_size != 0) && (pool->curr_size >= pool->max_size))

            return NULL;

        job = async_job_new();

        if (job != NULL) {

            if (! async_fibre_makecontext(&job->fibrectx)) {

                async_job_free(job);

                return NULL;

            }

            pool->curr_size++;

        }

    }

    return job;

}

static void async_release_job(ASYNC_JOB *job) {

    async_pool *pool;

    pool = (async_pool *)CRYPTO_THREAD_get_local(&poolkey);

    OPENSSL_free(job->funcargs);

    job->funcargs = NULL;

    sk_ASYNC_JOB_push(pool->jobs, job);

}

void async_start_func(void)

{

    ASYNC_JOB *job;

    async_ctx *ctx = async_get_ctx();

    while (1) {

        /* Run the job */

        job = ctx->currjob;

        job->ret = job->func(job->funcargs);

        /* Stop the job */

        job->status = ASYNC_JOB_STOPPING;

        if (!async_fibre_swapcontext(&job->fibrectx,

                                     &ctx->dispatcher, 1)) {

            /*

             * Should not happen. Getting here will close the thread...can't do

             * much about it

             */

            ASYNCerr(ASYNC_F_ASYNC_START_FUNC, ASYNC_R_FAILED_TO_SWAP_CONTEXT);

        }

    }

}

int ASYNC_start_job(ASYNC_JOB **job, ASYNC_WAIT_CTX *wctx, int *ret,

                    int (*func)(void *), void *args, size_t size)

{

    async_ctx *ctx;

    if (!OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL))

        return ASYNC_ERR;

    ctx = async_get_ctx();

    if (ctx == NULL)

        ctx = async_ctx_new();

    if (ctx == NULL)

        return ASYNC_ERR;

    if (*job)

        ctx->currjob = *job;

    for (;;) {

        if (ctx->currjob != NULL) {

            if (ctx->currjob->status == ASYNC_JOB_STOPPING) {

                *ret = ctx->currjob->ret;

                ctx->currjob->waitctx = NULL;

                async_release_job(ctx->currjob);

                ctx->currjob = NULL;

                *job = NULL;

                return ASYNC_FINISH;

            }

            if (ctx->currjob->status == ASYNC_JOB_PAUSING) {

                *job = ctx->currjob;

                ctx->currjob->status = ASYNC_JOB_PAUSED;

                ctx->currjob = NULL;

                return ASYNC_PAUSE;

            }

            if (ctx->currjob->status == ASYNC_JOB_PAUSED) {

                ctx->currjob = *job;

                /* Resume previous job */

                if (!async_fibre_swapcontext(&ctx->dispatcher,

                        &ctx->currjob->fibrectx, 1)) {

                    ASYNCerr(ASYNC_F_ASYNC_START_JOB,

                             ASYNC_R_FAILED_TO_SWAP_CONTEXT);

                    goto err;

                }

                continue;

            }

            /* Should not happen */

            ASYNCerr(ASYNC_F_ASYNC_START_JOB, ERR_R_INTERNAL_ERROR);

            async_release_job(ctx->currjob);

            ctx->currjob = NULL;

            *job = NULL;

            return ASYNC_ERR;

        }

        /* Start a new job */

        if ((ctx->currjob = async_get_pool_job()) == NULL)

            return ASYNC_NO_JOBS;

        if (args != NULL) {

            ctx->currjob->funcargs = OPENSSL_malloc(size);

            if (ctx->currjob->funcargs == NULL) {

                ASYNCerr(ASYNC_F_ASYNC_START_JOB, ERR_R_MALLOC_FAILURE);

                async_release_job(ctx->currjob);

                ctx->currjob = NULL;

                return ASYNC_ERR;

            }

            memcpy(ctx->currjob->funcargs, args, size);

        } else {

            ctx->currjob->funcargs = NULL;

        }

        ctx->currjob->func = func;

        ctx->currjob->waitctx = wctx;

        if (!async_fibre_swapcontext(&ctx->dispatcher,

                &ctx->currjob->fibrectx, 1)) {

            ASYNCerr(ASYNC_F_ASYNC_START_JOB, ASYNC_R_FAILED_TO_SWAP_CONTEXT);

            goto err;

        }

    }

err:

    async_release_job(ctx->currjob);

    ctx->currjob = NULL;

    *job = NULL;

    return ASYNC_ERR;

}

int ASYNC_pause_job(void)

{

    ASYNC_JOB *job;

    async_ctx *ctx = async_get_ctx();

    if (ctx == NULL

            || ctx->currjob == NULL

            || ctx->blocked) {

        /*

         * Could be we've deliberately not been started within a job so this is

         * counted as success.

         */

        return 1;

    }

    job = ctx->currjob;

    job->status = ASYNC_JOB_PAUSING;

    if (!async_fibre_swapcontext(&job->fibrectx,

                                 &ctx->dispatcher, 1)) {

        ASYNCerr(ASYNC_F_ASYNC_PAUSE_JOB, ASYNC_R_FAILED_TO_SWAP_CONTEXT);

        return 0;

    }

    /* Reset counts of added and deleted fds */

    async_wait_ctx_reset_counts(job->waitctx);

    return 1;

}

static void async_empty_pool(async_pool *pool)

{

    ASYNC_JOB *job;

    if (!pool || !pool->jobs)

        return;

    do {

        job = sk_ASYNC_JOB_pop(pool->jobs);

        async_job_free(job);

    } while (job);

}

int async_init(void)

{

    if (!CRYPTO_THREAD_init_local(&ctxkey, NULL))

        return 0;

    if (!CRYPTO_THREAD_init_local(&poolkey, NULL)) {

        CRYPTO_THREAD_cleanup_local(&ctxkey);

        return 0;

    }

    return 1;

}

void async_deinit(void)

{

    CRYPTO_THREAD_cleanup_local(&ctxkey);

    CRYPTO_THREAD_cleanup_local(&poolkey);

}

int ASYNC_init_thread(size_t max_size, size_t init_size)

{

    async_pool *pool;

    size_t curr_size = 0;

    if (init_size > max_size) {

        ASYNCerr(ASYNC_F_ASYNC_INIT_THREAD, ASYNC_R_INVALID_POOL_SIZE);

        return 0;

    }

    if (!OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL))

        return 0;

    if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_ASYNC))

        return 0;

    pool = OPENSSL_zalloc(sizeof(*pool));

    if (pool == NULL) {

        ASYNCerr(ASYNC_F_ASYNC_INIT_THREAD, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    pool->jobs = sk_ASYNC_JOB_new_reserve(NULL, init_size);

    if (pool->jobs == NULL) {

        ASYNCerr(ASYNC_F_ASYNC_INIT_THREAD, ERR_R_MALLOC_FAILURE);

        OPENSSL_free(pool);

        return 0;

    }

    pool->max_size = max_size;

    /* Pre-create jobs as required */

    while (init_size--) {

        ASYNC_JOB *job;

        job = async_job_new();

        if (job == NULL || !async_fibre_makecontext(&job->fibrectx)) {

            /*

             * Not actually fatal because we already created the pool, just

             * skip creation of any more jobs

             */

            async_job_free(job);

            break;

        }

        job->funcargs = NULL;

        sk_ASYNC_JOB_push(pool->jobs, job); /* Cannot fail due to reserve */

        curr_size++;

    }

    pool->curr_size = curr_size;

    if (!CRYPTO_THREAD_set_local(&poolkey, pool)) {

        ASYNCerr(ASYNC_F_ASYNC_INIT_THREAD, ASYNC_R_FAILED_TO_SET_POOL);

        goto err;

    }

    return 1;

err:

    async_empty_pool(pool);

    sk_ASYNC_JOB_free(pool->jobs);

    OPENSSL_free(pool);

    return 0;

}

void async_delete_thread_state(void)

{

    async_pool *pool = (async_pool *)CRYPTO_THREAD_get_local(&poolkey);

    if (pool != NULL) {

        async_empty_pool(pool);

        sk_ASYNC_JOB_free(pool->jobs);

        OPENSSL_free(pool);

        CRYPTO_THREAD_set_local(&poolkey, NULL);

    }

    async_local_cleanup();

    async_ctx_free();

}

void ASYNC_cleanup_thread(void)

{

    if (!OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL))

        return;

    async_delete_thread_state();

}

ASYNC_JOB *ASYNC_get_current_job(void)

{

    async_ctx *ctx;

    if (!OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL))

        return NULL;

    ctx = async_get_ctx();

    if (ctx == NULL)

        return NULL;

    return ctx->currjob;

}

ASYNC_WAIT_CTX *ASYNC_get_wait_ctx(ASYNC_JOB *job)

{

    return job->waitctx;

}

void ASYNC_block_pause(void)

{

    async_ctx *ctx;

    if (!OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL))

        return;

    ctx = async_get_ctx();

    if (ctx == NULL || ctx->currjob == NULL) {

        /*

         * We're not in a job anyway so ignore this

         */

        return;

    }

    ctx->blocked++;

}

void ASYNC_unblock_pause(void)

{

    async_ctx *ctx;

    if (!OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL))

        return;

    ctx = async_get_ctx();

    if (ctx == NULL || ctx->currjob == NULL) {

        /*

         * We're not in a job anyway so ignore this

         */

        return;

    }

    if (ctx->blocked > 0)

        ctx->blocked--;

}