crypto/async/async.c - third_party/openssl - Git at Google

 /*
  * Copyright 2015-2016 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_locl.h"

 #include <openssl/err.h>
 #include <internal/cryptlib_int.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 void async_free_pool_internal(async_pool *pool);

 static async_ctx *async_ctx_new(void)
 {
     async_ctx *nctx = NULL;

     nctx = OPENSSL_malloc(sizeof (async_ctx));
     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)
 {
     if (!OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL))
         return NULL;

     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 (ASYNC_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 = 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_null();
     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);
         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_free_pool_internal(pool);
     return 0;
 }

 static void async_free_pool_internal(async_pool *pool)
 {
     if (pool == NULL)
         return;

     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)
 {
     async_free_pool_internal((async_pool *)CRYPTO_THREAD_get_local(&poolkey));
 }

 ASYNC_JOB *ASYNC_get_current_job(void)
 {
     async_ctx *ctx;

     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 = 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 = 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--;
 }
	/*
	* Copyright 2015-2016 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_locl.h"

	#include <openssl/err.h>
	#include <internal/cryptlib_int.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 void async_free_pool_internal(async_pool *pool);

	static async_ctx *async_ctx_new(void)
	{
	async_ctx *nctx = NULL;

	nctx = OPENSSL_malloc(sizeof (async_ctx));
	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)
	{
	if (!OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL))
	return NULL;

	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 (ASYNC_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 = 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_null();
	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);
	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_free_pool_internal(pool);
	return 0;
	}

	static void async_free_pool_internal(async_pool *pool)
	{
	if (pool == NULL)
	return;

	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)
	{
	async_free_pool_internal((async_pool *)CRYPTO_THREAD_get_local(&poolkey));
	}

	ASYNC_JOB *ASYNC_get_current_job(void)
	{
	async_ctx *ctx;

	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 = 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 = 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--;
	}