tor-browser

evrpc.c (29369B)

---

/*
* Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
* Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
*
* 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.
* 3. The name of the author may not be used to endorse or promote products
*    derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 "event2/event-config.h"
#include "evconfig-private.h"

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <windows.h>
#undef WIN32_LEAN_AND_MEAN
#endif

#include <sys/types.h>
#ifndef _WIN32
#include <sys/socket.h>
#endif
#ifdef EVENT__HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include <sys/queue.h>
#include <stdio.h>
#include <stdlib.h>
#ifndef _WIN32
#include <unistd.h>
#endif
#include <errno.h>
#include <signal.h>
#include <string.h>

#include <sys/queue.h>

#include "event2/event.h"
#include "event2/event_struct.h"
#include "event2/rpc.h"
#include "event2/rpc_struct.h"
#include "evrpc-internal.h"
#include "event2/http.h"
#include "event2/buffer.h"
#include "event2/tag.h"
#include "event2/http_struct.h"
#include "event2/http_compat.h"
#include "event2/util.h"
#include "util-internal.h"
#include "log-internal.h"
#include "mm-internal.h"

struct evrpc_base *
evrpc_init(struct evhttp *http_server)
{
struct evrpc_base* base = mm_calloc(1, sizeof(struct evrpc_base));
if (base == NULL)
	return (NULL);

/* we rely on the tagging sub system */
evtag_init();

TAILQ_INIT(&base->registered_rpcs);
TAILQ_INIT(&base->input_hooks);
TAILQ_INIT(&base->output_hooks);

TAILQ_INIT(&base->paused_requests);

base->http_server = http_server;

return (base);
}

void
evrpc_free(struct evrpc_base *base)
{
struct evrpc *rpc;
struct evrpc_hook *hook;
struct evrpc_hook_ctx *pause;
int r;

while ((rpc = TAILQ_FIRST(&base->registered_rpcs)) != NULL) {
	r = evrpc_unregister_rpc(base, rpc->uri);
	EVUTIL_ASSERT(r == 0);
}
while ((pause = TAILQ_FIRST(&base->paused_requests)) != NULL) {
	TAILQ_REMOVE(&base->paused_requests, pause, next);
	mm_free(pause);
}
while ((hook = TAILQ_FIRST(&base->input_hooks)) != NULL) {
	r = evrpc_remove_hook(base, EVRPC_INPUT, hook);
	EVUTIL_ASSERT(r);
}
while ((hook = TAILQ_FIRST(&base->output_hooks)) != NULL) {
	r = evrpc_remove_hook(base, EVRPC_OUTPUT, hook);
	EVUTIL_ASSERT(r);
}
mm_free(base);
}

void *
evrpc_add_hook(void *vbase,
   enum EVRPC_HOOK_TYPE hook_type,
   int (*cb)(void *, struct evhttp_request *, struct evbuffer *, void *),
   void *cb_arg)
{
struct evrpc_hooks_ *base = vbase;
struct evrpc_hook_list *head = NULL;
struct evrpc_hook *hook = NULL;
switch (hook_type) {
case EVRPC_INPUT:
	head = &base->in_hooks;
	break;
case EVRPC_OUTPUT:
	head = &base->out_hooks;
	break;
default:
	EVUTIL_ASSERT(hook_type == EVRPC_INPUT || hook_type == EVRPC_OUTPUT);
}

hook = mm_calloc(1, sizeof(struct evrpc_hook));
EVUTIL_ASSERT(hook != NULL);

hook->process = cb;
hook->process_arg = cb_arg;
TAILQ_INSERT_TAIL(head, hook, next);

return (hook);
}

static int
evrpc_remove_hook_internal(struct evrpc_hook_list *head, void *handle)
{
struct evrpc_hook *hook = NULL;
TAILQ_FOREACH(hook, head, next) {
	if (hook == handle) {
		TAILQ_REMOVE(head, hook, next);
		mm_free(hook);
		return (1);
	}
}

return (0);
}

/*
* remove the hook specified by the handle
*/

int
evrpc_remove_hook(void *vbase, enum EVRPC_HOOK_TYPE hook_type, void *handle)
{
struct evrpc_hooks_ *base = vbase;
struct evrpc_hook_list *head = NULL;
switch (hook_type) {
case EVRPC_INPUT:
	head = &base->in_hooks;
	break;
case EVRPC_OUTPUT:
	head = &base->out_hooks;
	break;
default:
	EVUTIL_ASSERT(hook_type == EVRPC_INPUT || hook_type == EVRPC_OUTPUT);
}

return (evrpc_remove_hook_internal(head, handle));
}

static int
evrpc_process_hooks(struct evrpc_hook_list *head, void *ctx,
   struct evhttp_request *req, struct evbuffer *evbuf)
{
struct evrpc_hook *hook;
TAILQ_FOREACH(hook, head, next) {
	int res = hook->process(ctx, req, evbuf, hook->process_arg);
	if (res != EVRPC_CONTINUE)
		return (res);
}

return (EVRPC_CONTINUE);
}

static void evrpc_pool_schedule(struct evrpc_pool *pool);
static void evrpc_request_cb(struct evhttp_request *, void *);

/*
* Registers a new RPC with the HTTP server.   The evrpc object is expected
* to have been filled in via the EVRPC_REGISTER_OBJECT macro which in turn
* calls this function.
*/

static char *
evrpc_construct_uri(const char *uri)
{
char *constructed_uri;
size_t constructed_uri_len;

constructed_uri_len = strlen(EVRPC_URI_PREFIX) + strlen(uri) + 1;
if ((constructed_uri = mm_malloc(constructed_uri_len)) == NULL)
	event_err(1, "%s: failed to register rpc at %s",
	    __func__, uri);
memcpy(constructed_uri, EVRPC_URI_PREFIX, strlen(EVRPC_URI_PREFIX));
memcpy(constructed_uri + strlen(EVRPC_URI_PREFIX), uri, strlen(uri));
constructed_uri[constructed_uri_len - 1] = '\0';

return (constructed_uri);
}

int
evrpc_register_rpc(struct evrpc_base *base, struct evrpc *rpc,
   void (*cb)(struct evrpc_req_generic *, void *), void *cb_arg)
{
char *constructed_uri = evrpc_construct_uri(rpc->uri);

rpc->base = base;
rpc->cb = cb;
rpc->cb_arg = cb_arg;

TAILQ_INSERT_TAIL(&base->registered_rpcs, rpc, next);

evhttp_set_cb(base->http_server,
    constructed_uri,
    evrpc_request_cb,
    rpc);

mm_free(constructed_uri);

return (0);
}

int
evrpc_unregister_rpc(struct evrpc_base *base, const char *name)
{
char *registered_uri = NULL;
struct evrpc *rpc;
int r;

/* find the right rpc; linear search might be slow */
TAILQ_FOREACH(rpc, &base->registered_rpcs, next) {
	if (strcmp(rpc->uri, name) == 0)
		break;
}
if (rpc == NULL) {
	/* We did not find an RPC with this name */
	return (-1);
}
TAILQ_REMOVE(&base->registered_rpcs, rpc, next);

registered_uri = evrpc_construct_uri(name);

/* remove the http server callback */
r = evhttp_del_cb(base->http_server, registered_uri);
EVUTIL_ASSERT(r == 0);

mm_free(registered_uri);

mm_free((char *)rpc->uri);
mm_free(rpc);
return (0);
}

static int evrpc_pause_request(void *vbase, void *ctx,
   void (*cb)(void *, enum EVRPC_HOOK_RESULT));
static void evrpc_request_cb_closure(void *, enum EVRPC_HOOK_RESULT);

static void
evrpc_request_cb(struct evhttp_request *req, void *arg)
{
struct evrpc *rpc = arg;
struct evrpc_req_generic *rpc_state = NULL;

/* let's verify the outside parameters */
if (req->type != EVHTTP_REQ_POST ||
    evbuffer_get_length(req->input_buffer) <= 0)
	goto error;

rpc_state = mm_calloc(1, sizeof(struct evrpc_req_generic));
if (rpc_state == NULL)
	goto error;
rpc_state->rpc = rpc;
rpc_state->http_req = req;
rpc_state->rpc_data = NULL;

if (TAILQ_FIRST(&rpc->base->input_hooks) != NULL) {
	int hook_res;

	evrpc_hook_associate_meta_(&rpc_state->hook_meta, req->evcon);

	/*
	 * allow hooks to modify the outgoing request
	 */
	hook_res = evrpc_process_hooks(&rpc->base->input_hooks,
	    rpc_state, req, req->input_buffer);
	switch (hook_res) {
	case EVRPC_TERMINATE:
		goto error;
	case EVRPC_PAUSE:
		evrpc_pause_request(rpc->base, rpc_state,
		    evrpc_request_cb_closure);
		return;
	case EVRPC_CONTINUE:
		break;
	default:
		EVUTIL_ASSERT(hook_res == EVRPC_TERMINATE ||
		    hook_res == EVRPC_CONTINUE ||
		    hook_res == EVRPC_PAUSE);
	}
}

evrpc_request_cb_closure(rpc_state, EVRPC_CONTINUE);
return;

error:
if (rpc_state)
	evrpc_reqstate_free_(rpc_state);
evhttp_send_error(req, HTTP_SERVUNAVAIL, NULL);
return;
}

static void
evrpc_request_cb_closure(void *arg, enum EVRPC_HOOK_RESULT hook_res)
{
struct evrpc_req_generic *rpc_state = arg;
struct evrpc *rpc;
struct evhttp_request *req;

EVUTIL_ASSERT(rpc_state);
rpc = rpc_state->rpc;
req = rpc_state->http_req;

if (hook_res == EVRPC_TERMINATE)
	goto error;

/* let's check that we can parse the request */
rpc_state->request = rpc->request_new(rpc->request_new_arg);
if (rpc_state->request == NULL)
	goto error;

if (rpc->request_unmarshal(
	    rpc_state->request, req->input_buffer) == -1) {
	/* we failed to parse the request; that's a bummer */
	goto error;
}

/* at this point, we have a well formed request, prepare the reply */

rpc_state->reply = rpc->reply_new(rpc->reply_new_arg);
if (rpc_state->reply == NULL)
	goto error;

/* give the rpc to the user; they can deal with it */
rpc->cb(rpc_state, rpc->cb_arg);

return;

error:
evrpc_reqstate_free_(rpc_state);
evhttp_send_error(req, HTTP_SERVUNAVAIL, NULL);
return;
}


void
evrpc_reqstate_free_(struct evrpc_req_generic* rpc_state)
{
struct evrpc *rpc;
EVUTIL_ASSERT(rpc_state != NULL);
rpc = rpc_state->rpc;

/* clean up all memory */
if (rpc_state->hook_meta != NULL)
	evrpc_hook_context_free_(rpc_state->hook_meta);
if (rpc_state->request != NULL)
	rpc->request_free(rpc_state->request);
if (rpc_state->reply != NULL)
	rpc->reply_free(rpc_state->reply);
if (rpc_state->rpc_data != NULL)
	evbuffer_free(rpc_state->rpc_data);
mm_free(rpc_state);
}

static void
evrpc_request_done_closure(void *, enum EVRPC_HOOK_RESULT);

void
evrpc_request_done(struct evrpc_req_generic *rpc_state)
{
struct evhttp_request *req;
struct evrpc *rpc;

EVUTIL_ASSERT(rpc_state);

req = rpc_state->http_req;
rpc = rpc_state->rpc;

if (rpc->reply_complete(rpc_state->reply) == -1) {
	/* the reply was not completely filled in.  error out */
	goto error;
}

if ((rpc_state->rpc_data = evbuffer_new()) == NULL) {
	/* out of memory */
	goto error;
}

/* serialize the reply */
rpc->reply_marshal(rpc_state->rpc_data, rpc_state->reply);

if (TAILQ_FIRST(&rpc->base->output_hooks) != NULL) {
	int hook_res;

	evrpc_hook_associate_meta_(&rpc_state->hook_meta, req->evcon);

	/* do hook based tweaks to the request */
	hook_res = evrpc_process_hooks(&rpc->base->output_hooks,
	    rpc_state, req, rpc_state->rpc_data);
	switch (hook_res) {
	case EVRPC_TERMINATE:
		goto error;
	case EVRPC_PAUSE:
		if (evrpc_pause_request(rpc->base, rpc_state,
			evrpc_request_done_closure) == -1)
			goto error;
		return;
	case EVRPC_CONTINUE:
		break;
	default:
		EVUTIL_ASSERT(hook_res == EVRPC_TERMINATE ||
		    hook_res == EVRPC_CONTINUE ||
		    hook_res == EVRPC_PAUSE);
	}
}

evrpc_request_done_closure(rpc_state, EVRPC_CONTINUE);
return;

error:
evrpc_reqstate_free_(rpc_state);
evhttp_send_error(req, HTTP_SERVUNAVAIL, NULL);
return;
}

void *
evrpc_get_request(struct evrpc_req_generic *req)
{
return req->request;
}

void *
evrpc_get_reply(struct evrpc_req_generic *req)
{
return req->reply;
}

static void
evrpc_request_done_closure(void *arg, enum EVRPC_HOOK_RESULT hook_res)
{
struct evrpc_req_generic *rpc_state = arg;
struct evhttp_request *req;
EVUTIL_ASSERT(rpc_state);
req = rpc_state->http_req;

if (hook_res == EVRPC_TERMINATE)
	goto error;

/* on success, we are going to transmit marshaled binary data */
if (evhttp_find_header(req->output_headers, "Content-Type") == NULL) {
	evhttp_add_header(req->output_headers,
	    "Content-Type", "application/octet-stream");
}
evhttp_send_reply(req, HTTP_OK, "OK", rpc_state->rpc_data);

evrpc_reqstate_free_(rpc_state);

return;

error:
evrpc_reqstate_free_(rpc_state);
evhttp_send_error(req, HTTP_SERVUNAVAIL, NULL);
return;
}


/* Client implementation of RPC site */

static int evrpc_schedule_request(struct evhttp_connection *connection,
   struct evrpc_request_wrapper *ctx);

struct evrpc_pool *
evrpc_pool_new(struct event_base *base)
{
struct evrpc_pool *pool = mm_calloc(1, sizeof(struct evrpc_pool));
if (pool == NULL)
	return (NULL);

TAILQ_INIT(&pool->connections);
TAILQ_INIT(&pool->requests);

TAILQ_INIT(&pool->paused_requests);

TAILQ_INIT(&pool->input_hooks);
TAILQ_INIT(&pool->output_hooks);

pool->base = base;
pool->timeout = -1;

return (pool);
}

static void
evrpc_request_wrapper_free(struct evrpc_request_wrapper *request)
{
if (request->hook_meta != NULL)
	evrpc_hook_context_free_(request->hook_meta);
mm_free(request->name);
mm_free(request);
}

void
evrpc_pool_free(struct evrpc_pool *pool)
{
struct evhttp_connection *connection;
struct evrpc_request_wrapper *request;
struct evrpc_hook_ctx *pause;
struct evrpc_hook *hook;
int r;

while ((request = TAILQ_FIRST(&pool->requests)) != NULL) {
	TAILQ_REMOVE(&pool->requests, request, next);
	evrpc_request_wrapper_free(request);
}

while ((pause = TAILQ_FIRST(&pool->paused_requests)) != NULL) {
	TAILQ_REMOVE(&pool->paused_requests, pause, next);
	mm_free(pause);
}

while ((connection = TAILQ_FIRST(&pool->connections)) != NULL) {
	TAILQ_REMOVE(&pool->connections, connection, next);
	evhttp_connection_free(connection);
}

while ((hook = TAILQ_FIRST(&pool->input_hooks)) != NULL) {
	r = evrpc_remove_hook(pool, EVRPC_INPUT, hook);
	EVUTIL_ASSERT(r);
}

while ((hook = TAILQ_FIRST(&pool->output_hooks)) != NULL) {
	r = evrpc_remove_hook(pool, EVRPC_OUTPUT, hook);
	EVUTIL_ASSERT(r);
}

mm_free(pool);
}

/*
* Add a connection to the RPC pool.   A request scheduled on the pool
* may use any available connection.
*/

void
evrpc_pool_add_connection(struct evrpc_pool *pool,
   struct evhttp_connection *connection)
{
EVUTIL_ASSERT(connection->http_server == NULL);
TAILQ_INSERT_TAIL(&pool->connections, connection, next);

/*
 * associate an event base with this connection
 */
if (pool->base != NULL)
	evhttp_connection_set_base(connection, pool->base);

/*
 * unless a timeout was specifically set for a connection,
 * the connection inherits the timeout from the pool.
 */
if (!evutil_timerisset(&connection->timeout))
	evhttp_connection_set_timeout(connection, pool->timeout);

/*
 * if we have any requests pending, schedule them with the new
 * connections.
 */

if (TAILQ_FIRST(&pool->requests) != NULL) {
	struct evrpc_request_wrapper *request =
	    TAILQ_FIRST(&pool->requests);
	TAILQ_REMOVE(&pool->requests, request, next);
	evrpc_schedule_request(connection, request);
}
}

void
evrpc_pool_remove_connection(struct evrpc_pool *pool,
   struct evhttp_connection *connection)
{
TAILQ_REMOVE(&pool->connections, connection, next);
}

void
evrpc_pool_set_timeout(struct evrpc_pool *pool, int timeout_in_secs)
{
struct evhttp_connection *evcon;
TAILQ_FOREACH(evcon, &pool->connections, next) {
	evhttp_connection_set_timeout(evcon, timeout_in_secs);
}
pool->timeout = timeout_in_secs;
}


static void evrpc_reply_done(struct evhttp_request *, void *);
static void evrpc_request_timeout(evutil_socket_t, short, void *);

/*
* Finds a connection object associated with the pool that is currently
* idle and can be used to make a request.
*/
static struct evhttp_connection *
evrpc_pool_find_connection(struct evrpc_pool *pool)
{
struct evhttp_connection *connection;
TAILQ_FOREACH(connection, &pool->connections, next) {
	if (TAILQ_FIRST(&connection->requests) == NULL)
		return (connection);
}

return (NULL);
}

/*
* Prototypes responsible for evrpc scheduling and hooking
*/

static void evrpc_schedule_request_closure(void *ctx, enum EVRPC_HOOK_RESULT);

/*
* We assume that the ctx is no longer queued on the pool.
*/
static int
evrpc_schedule_request(struct evhttp_connection *connection,
   struct evrpc_request_wrapper *ctx)
{
struct evhttp_request *req = NULL;
struct evrpc_pool *pool = ctx->pool;
struct evrpc_status status;

if ((req = evhttp_request_new(evrpc_reply_done, ctx)) == NULL)
	goto error;

/* serialize the request data into the output buffer */
ctx->request_marshal(req->output_buffer, ctx->request);

/* we need to know the connection that we might have to abort */
ctx->evcon = connection;

/* if we get paused we also need to know the request */
ctx->req = req;

if (TAILQ_FIRST(&pool->output_hooks) != NULL) {
	int hook_res;

	evrpc_hook_associate_meta_(&ctx->hook_meta, connection);

	/* apply hooks to the outgoing request */
	hook_res = evrpc_process_hooks(&pool->output_hooks,
	    ctx, req, req->output_buffer);

	switch (hook_res) {
	case EVRPC_TERMINATE:
		goto error;
	case EVRPC_PAUSE:
		/* we need to be explicitly resumed */
		if (evrpc_pause_request(pool, ctx,
			evrpc_schedule_request_closure) == -1)
			goto error;
		return (0);
	case EVRPC_CONTINUE:
		/* we can just continue */
		break;
	default:
		EVUTIL_ASSERT(hook_res == EVRPC_TERMINATE ||
		    hook_res == EVRPC_CONTINUE ||
		    hook_res == EVRPC_PAUSE);
	}
}

evrpc_schedule_request_closure(ctx, EVRPC_CONTINUE);
return (0);

error:
memset(&status, 0, sizeof(status));
status.error = EVRPC_STATUS_ERR_UNSTARTED;
(*ctx->cb)(&status, ctx->request, ctx->reply, ctx->cb_arg);
evrpc_request_wrapper_free(ctx);
return (-1);
}

static void
evrpc_schedule_request_closure(void *arg, enum EVRPC_HOOK_RESULT hook_res)
{
struct evrpc_request_wrapper *ctx = arg;
struct evhttp_connection *connection = ctx->evcon;
struct evhttp_request *req = ctx->req;
struct evrpc_pool *pool = ctx->pool;
struct evrpc_status status;
char *uri = NULL;
int res = 0;

if (hook_res == EVRPC_TERMINATE)
	goto error;

uri = evrpc_construct_uri(ctx->name);
if (uri == NULL)
	goto error;

if (pool->timeout > 0) {
	/*
	 * a timeout after which the whole rpc is going to be aborted.
	 */
	struct timeval tv;
	evutil_timerclear(&tv);
	tv.tv_sec = pool->timeout;
	evtimer_add(&ctx->ev_timeout, &tv);
}

/* start the request over the connection */
res = evhttp_make_request(connection, req, EVHTTP_REQ_POST, uri);
mm_free(uri);

if (res == -1)
	goto error;

return;

error:
memset(&status, 0, sizeof(status));
status.error = EVRPC_STATUS_ERR_UNSTARTED;
(*ctx->cb)(&status, ctx->request, ctx->reply, ctx->cb_arg);
evrpc_request_wrapper_free(ctx);
}

/* we just queue the paused request on the pool under the req object */
static int
evrpc_pause_request(void *vbase, void *ctx,
   void (*cb)(void *, enum EVRPC_HOOK_RESULT))
{
struct evrpc_hooks_ *base = vbase;
struct evrpc_hook_ctx *pause = mm_malloc(sizeof(*pause));
if (pause == NULL)
	return (-1);

pause->ctx = ctx;
pause->cb = cb;

TAILQ_INSERT_TAIL(&base->pause_requests, pause, next);
return (0);
}

int
evrpc_resume_request(void *vbase, void *ctx, enum EVRPC_HOOK_RESULT res)
{
struct evrpc_hooks_ *base = vbase;
struct evrpc_pause_list *head = &base->pause_requests;
struct evrpc_hook_ctx *pause;

TAILQ_FOREACH(pause, head, next) {
	if (pause->ctx == ctx)
		break;
}

if (pause == NULL)
	return (-1);

(*pause->cb)(pause->ctx, res);
TAILQ_REMOVE(head, pause, next);
mm_free(pause);
return (0);
}

int
evrpc_make_request(struct evrpc_request_wrapper *ctx)
{
struct evrpc_pool *pool = ctx->pool;

/* initialize the event structure for this rpc */
evtimer_assign(&ctx->ev_timeout, pool->base, evrpc_request_timeout, ctx);

/* we better have some available connections on the pool */
EVUTIL_ASSERT(TAILQ_FIRST(&pool->connections) != NULL);

/*
 * if no connection is available, we queue the request on the pool,
 * the next time a connection is empty, the rpc will be send on that.
 */
TAILQ_INSERT_TAIL(&pool->requests, ctx, next);

evrpc_pool_schedule(pool);

return (0);
}


struct evrpc_request_wrapper *
evrpc_make_request_ctx(
struct evrpc_pool *pool, void *request, void *reply,
const char *rpcname,
void (*req_marshal)(struct evbuffer*, void *),
void (*rpl_clear)(void *),
int (*rpl_unmarshal)(void *, struct evbuffer *),
void (*cb)(struct evrpc_status *, void *, void *, void *),
void *cbarg)
{
struct evrpc_request_wrapper *ctx = (struct evrpc_request_wrapper *)
    mm_malloc(sizeof(struct evrpc_request_wrapper));
if (ctx == NULL)
	return (NULL);

ctx->pool = pool;
ctx->hook_meta = NULL;
ctx->evcon = NULL;
ctx->name = mm_strdup(rpcname);
if (ctx->name == NULL) {
	mm_free(ctx);
	return (NULL);
}
ctx->cb = cb;
ctx->cb_arg = cbarg;
ctx->request = request;
ctx->reply = reply;
ctx->request_marshal = req_marshal;
ctx->reply_clear = rpl_clear;
ctx->reply_unmarshal = rpl_unmarshal;

return (ctx);
}

static void
evrpc_reply_done_closure(void *, enum EVRPC_HOOK_RESULT);

static void
evrpc_reply_done(struct evhttp_request *req, void *arg)
{
struct evrpc_request_wrapper *ctx = arg;
struct evrpc_pool *pool = ctx->pool;
int hook_res = EVRPC_CONTINUE;

/* cancel any timeout we might have scheduled */
event_del(&ctx->ev_timeout);

ctx->req = req;

/* we need to get the reply now */
if (req == NULL) {
	evrpc_reply_done_closure(ctx, EVRPC_CONTINUE);
	return;
}

if (TAILQ_FIRST(&pool->input_hooks) != NULL) {
	evrpc_hook_associate_meta_(&ctx->hook_meta, ctx->evcon);

	/* apply hooks to the incoming request */
	hook_res = evrpc_process_hooks(&pool->input_hooks,
	    ctx, req, req->input_buffer);

	switch (hook_res) {
	case EVRPC_TERMINATE:
	case EVRPC_CONTINUE:
		break;
	case EVRPC_PAUSE:
		/*
		 * if we get paused we also need to know the
		 * request.  unfortunately, the underlying
		 * layer is going to free it.  we need to
		 * request ownership explicitly
		 */
		evhttp_request_own(req);

		evrpc_pause_request(pool, ctx,
		    evrpc_reply_done_closure);
		return;
	default:
		EVUTIL_ASSERT(hook_res == EVRPC_TERMINATE ||
		    hook_res == EVRPC_CONTINUE ||
		    hook_res == EVRPC_PAUSE);
	}
}

evrpc_reply_done_closure(ctx, hook_res);

/* http request is being freed by underlying layer */
}

static void
evrpc_reply_done_closure(void *arg, enum EVRPC_HOOK_RESULT hook_res)
{
struct evrpc_request_wrapper *ctx = arg;
struct evhttp_request *req = ctx->req;
struct evrpc_pool *pool = ctx->pool;
struct evrpc_status status;
int res = -1;

memset(&status, 0, sizeof(status));
status.http_req = req;

/* we need to get the reply now */
if (req == NULL) {
	status.error = EVRPC_STATUS_ERR_TIMEOUT;
} else if (hook_res == EVRPC_TERMINATE) {
	status.error = EVRPC_STATUS_ERR_HOOKABORTED;
} else {
	res = ctx->reply_unmarshal(ctx->reply, req->input_buffer);
	if (res == -1)
		status.error = EVRPC_STATUS_ERR_BADPAYLOAD;
}

if (res == -1) {
	/* clear everything that we might have written previously */
	ctx->reply_clear(ctx->reply);
}

(*ctx->cb)(&status, ctx->request, ctx->reply, ctx->cb_arg);

evrpc_request_wrapper_free(ctx);

/* the http layer owned the original request structure, but if we
 * got paused, we asked for ownership and need to free it here. */
if (req != NULL && evhttp_request_is_owned(req))
	evhttp_request_free(req);

/* see if we can schedule another request */
evrpc_pool_schedule(pool);
}

static void
evrpc_pool_schedule(struct evrpc_pool *pool)
{
struct evrpc_request_wrapper *ctx = TAILQ_FIRST(&pool->requests);
struct evhttp_connection *evcon;

/* if no requests are pending, we have no work */
if (ctx == NULL)
	return;

if ((evcon = evrpc_pool_find_connection(pool)) != NULL) {
	TAILQ_REMOVE(&pool->requests, ctx, next);
	evrpc_schedule_request(evcon, ctx);
}
}

static void
evrpc_request_timeout(evutil_socket_t fd, short what, void *arg)
{
struct evrpc_request_wrapper *ctx = arg;
struct evhttp_connection *evcon = ctx->evcon;
EVUTIL_ASSERT(evcon != NULL);

evhttp_connection_fail_(evcon, EVREQ_HTTP_TIMEOUT);
}

/*
* frees potential meta data associated with a request.
*/

static void
evrpc_meta_data_free(struct evrpc_meta_list *meta_data)
{
struct evrpc_meta *entry;
EVUTIL_ASSERT(meta_data != NULL);

while ((entry = TAILQ_FIRST(meta_data)) != NULL) {
	TAILQ_REMOVE(meta_data, entry, next);
	mm_free(entry->key);
	mm_free(entry->data);
	mm_free(entry);
}
}

static struct evrpc_hook_meta *
evrpc_hook_meta_new_(void)
{
struct evrpc_hook_meta *ctx;
ctx = mm_malloc(sizeof(struct evrpc_hook_meta));
EVUTIL_ASSERT(ctx != NULL);

TAILQ_INIT(&ctx->meta_data);
ctx->evcon = NULL;

return (ctx);
}

static void
evrpc_hook_associate_meta_(struct evrpc_hook_meta **pctx,
   struct evhttp_connection *evcon)
{
struct evrpc_hook_meta *ctx = *pctx;
if (ctx == NULL)
	*pctx = ctx = evrpc_hook_meta_new_();
ctx->evcon = evcon;
}

static void
evrpc_hook_context_free_(struct evrpc_hook_meta *ctx)
{
evrpc_meta_data_free(&ctx->meta_data);
mm_free(ctx);
}

/* Adds meta data */
void
evrpc_hook_add_meta(void *ctx, const char *key,
   const void *data, size_t data_size)
{
struct evrpc_request_wrapper *req = ctx;
struct evrpc_hook_meta *store = NULL;
struct evrpc_meta *meta = NULL;

if ((store = req->hook_meta) == NULL)
	store = req->hook_meta = evrpc_hook_meta_new_();

meta = mm_malloc(sizeof(struct evrpc_meta));
EVUTIL_ASSERT(meta != NULL);
meta->key = mm_strdup(key);
EVUTIL_ASSERT(meta->key != NULL);
meta->data_size = data_size;
meta->data = mm_malloc(data_size);
EVUTIL_ASSERT(meta->data != NULL);
memcpy(meta->data, data, data_size);

TAILQ_INSERT_TAIL(&store->meta_data, meta, next);
}

int
evrpc_hook_find_meta(void *ctx, const char *key, void **data, size_t *data_size)
{
struct evrpc_request_wrapper *req = ctx;
struct evrpc_meta *meta = NULL;

if (req->hook_meta == NULL)
	return (-1);

TAILQ_FOREACH(meta, &req->hook_meta->meta_data, next) {
	if (strcmp(meta->key, key) == 0) {
		*data = meta->data;
		*data_size = meta->data_size;
		return (0);
	}
}

return (-1);
}

struct evhttp_connection *
evrpc_hook_get_connection(void *ctx)
{
struct evrpc_request_wrapper *req = ctx;
return (req->hook_meta != NULL ? req->hook_meta->evcon : NULL);
}

int
evrpc_send_request_generic(struct evrpc_pool *pool,
   void *request, void *reply,
   void (*cb)(struct evrpc_status *, void *, void *, void *),
   void *cb_arg,
   const char *rpcname,
   void (*req_marshal)(struct evbuffer *, void *),
   void (*rpl_clear)(void *),
   int (*rpl_unmarshal)(void *, struct evbuffer *))
{
struct evrpc_status status;
struct evrpc_request_wrapper *ctx;
ctx = evrpc_make_request_ctx(pool, request, reply,
    rpcname, req_marshal, rpl_clear, rpl_unmarshal, cb, cb_arg);
if (ctx == NULL)
	goto error;
return (evrpc_make_request(ctx));
error:
memset(&status, 0, sizeof(status));
status.error = EVRPC_STATUS_ERR_UNSTARTED;
(*(cb))(&status, request, reply, cb_arg);
return (-1);
}

/** Takes a request object and fills it in with the right magic */
static struct evrpc *
evrpc_register_object(const char *name,
   void *(*req_new)(void*), void *req_new_arg, void (*req_free)(void *),
   int (*req_unmarshal)(void *, struct evbuffer *),
   void *(*rpl_new)(void*), void *rpl_new_arg, void (*rpl_free)(void *),
   int (*rpl_complete)(void *),
   void (*rpl_marshal)(struct evbuffer *, void *))
{
struct evrpc* rpc = (struct evrpc *)mm_calloc(1, sizeof(struct evrpc));
if (rpc == NULL)
	return (NULL);
rpc->uri = mm_strdup(name);
if (rpc->uri == NULL) {
	mm_free(rpc);
	return (NULL);
}
rpc->request_new = req_new;
rpc->request_new_arg = req_new_arg;
rpc->request_free = req_free;
rpc->request_unmarshal = req_unmarshal;
rpc->reply_new = rpl_new;
rpc->reply_new_arg = rpl_new_arg;
rpc->reply_free = rpl_free;
rpc->reply_complete = rpl_complete;
rpc->reply_marshal = rpl_marshal;
return (rpc);
}

int
evrpc_register_generic(struct evrpc_base *base, const char *name,
   void (*callback)(struct evrpc_req_generic *, void *), void *cbarg,
   void *(*req_new)(void *), void *req_new_arg, void (*req_free)(void *),
   int (*req_unmarshal)(void *, struct evbuffer *),
   void *(*rpl_new)(void *), void *rpl_new_arg, void (*rpl_free)(void *),
   int (*rpl_complete)(void *),
   void (*rpl_marshal)(struct evbuffer *, void *))
{
struct evrpc* rpc =
    evrpc_register_object(name, req_new, req_new_arg, req_free, req_unmarshal,
	rpl_new, rpl_new_arg, rpl_free, rpl_complete, rpl_marshal);
if (rpc == NULL)
	return (-1);
evrpc_register_rpc(base, rpc,
    (void (*)(struct evrpc_req_generic*, void *))callback, cbarg);
return (0);
}

/** accessors for obscure and undocumented functionality */
struct evrpc_pool *
evrpc_request_get_pool(struct evrpc_request_wrapper *ctx)
{
return (ctx->pool);
}

void
evrpc_request_set_pool(struct evrpc_request_wrapper *ctx,
   struct evrpc_pool *pool)
{
ctx->pool = pool;
}

void
evrpc_request_set_cb(struct evrpc_request_wrapper *ctx,
   void (*cb)(struct evrpc_status*, void *request, void *reply, void *arg),
   void *cb_arg)
{
ctx->cb = cb;
ctx->cb_arg = cb_arg;
}