diff options
Diffstat (limited to 'extra/libevent/evrpc.c')
| -rw-r--r-- | extra/libevent/evrpc.c | 658 |
1 files changed, 658 insertions, 0 deletions
diff --git a/extra/libevent/evrpc.c b/extra/libevent/evrpc.c new file mode 100644 index 00000000000..bfe3087ef8a --- /dev/null +++ b/extra/libevent/evrpc.c @@ -0,0 +1,658 @@ +/* + * Copyright (c) 2000-2004 Niels Provos <provos@citi.umich.edu> + * All rights reserved. + * + * 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. + */ +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#ifdef WIN32 +#define WIN32_LEAN_AND_MEAN +#include <windows.h> +#include <winsock2.h> +#undef WIN32_LEAN_AND_MEAN +#include "misc.h" +#endif + +#include <sys/types.h> +#ifndef WIN32 +#include <sys/socket.h> +#endif +#ifdef 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 <assert.h> + +#include "event.h" +#include "evrpc.h" +#include "evrpc-internal.h" +#include "evhttp.h" +#include "evutil.h" +#include "log.h" + +struct evrpc_base * +evrpc_init(struct evhttp *http_server) +{ + struct evrpc_base* base = 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); + base->http_server = http_server; + + return (base); +} + +void +evrpc_free(struct evrpc_base *base) +{ + struct evrpc *rpc; + struct evrpc_hook *hook; + + while ((rpc = TAILQ_FIRST(&base->registered_rpcs)) != NULL) { + assert(evrpc_unregister_rpc(base, rpc->uri)); + } + while ((hook = TAILQ_FIRST(&base->input_hooks)) != NULL) { + assert(evrpc_remove_hook(base, INPUT, hook)); + } + while ((hook = TAILQ_FIRST(&base->output_hooks)) != NULL) { + assert(evrpc_remove_hook(base, OUTPUT, hook)); + } + free(base); +} + +void * +evrpc_add_hook(void *vbase, + enum EVRPC_HOOK_TYPE hook_type, + int (*cb)(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 INPUT: + head = &base->in_hooks; + break; + case OUTPUT: + head = &base->out_hooks; + break; + default: + assert(hook_type == INPUT || hook_type == OUTPUT); + } + + hook = calloc(1, sizeof(struct evrpc_hook)); + 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); + 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 INPUT: + head = &base->in_hooks; + break; + case OUTPUT: + head = &base->out_hooks; + break; + default: + assert(hook_type == INPUT || hook_type == OUTPUT); + } + + return (evrpc_remove_hook_internal(head, handle)); +} + +static int +evrpc_process_hooks(struct evrpc_hook_list *head, + struct evhttp_request *req, struct evbuffer *evbuf) +{ + struct evrpc_hook *hook; + TAILQ_FOREACH(hook, head, next) { + if (hook->process(req, evbuf, hook->process_arg) == -1) + return (-1); + } + + return (0); +} + +static void evrpc_pool_schedule(struct evrpc_pool *pool); +static void evrpc_request_cb(struct evhttp_request *, void *); +void evrpc_request_done(struct evrpc_req_generic*); + +/* + * 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; + int constructed_uri_len; + + constructed_uri_len = strlen(EVRPC_URI_PREFIX) + strlen(uri) + 1; + if ((constructed_uri = 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); + + free(constructed_uri); + + return (0); +} + +int +evrpc_unregister_rpc(struct evrpc_base *base, const char *name) +{ + char *registered_uri = NULL; + struct evrpc *rpc; + + /* 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); + + free((char *)rpc->uri); + free(rpc); + + registered_uri = evrpc_construct_uri(name); + + /* remove the http server callback */ + assert(evhttp_del_cb(base->http_server, registered_uri) == 0); + + free(registered_uri); + return (0); +} + +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_LENGTH(req->input_buffer) <= 0) + goto error; + + /* + * we might want to allow hooks to suspend the processing, + * but at the moment, we assume that they just act as simple + * filters. + */ + if (evrpc_process_hooks(&rpc->base->input_hooks, + req, req->input_buffer) == -1) + goto error; + + rpc_state = calloc(1, sizeof(struct evrpc_req_generic)); + if (rpc_state == NULL) + goto error; + + /* let's check that we can parse the request */ + rpc_state->request = rpc->request_new(); + if (rpc_state->request == NULL) + goto error; + + rpc_state->rpc = rpc; + + 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(); + if (rpc_state->reply == NULL) + goto error; + + rpc_state->http_req = req; + rpc_state->done = evrpc_request_done; + + /* 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, "Service Error"); + return; +} + +void +evrpc_reqstate_free(struct evrpc_req_generic* rpc_state) +{ + /* clean up all memory */ + if (rpc_state != NULL) { + struct evrpc *rpc = rpc_state->rpc; + + if (rpc_state->request != NULL) + rpc->request_free(rpc_state->request); + if (rpc_state->reply != NULL) + rpc->reply_free(rpc_state->reply); + free(rpc_state); + } +} + +void +evrpc_request_done(struct evrpc_req_generic* rpc_state) +{ + struct evhttp_request *req = rpc_state->http_req; + struct evrpc *rpc = rpc_state->rpc; + struct evbuffer* data = NULL; + + if (rpc->reply_complete(rpc_state->reply) == -1) { + /* the reply was not completely filled in. error out */ + goto error; + } + + if ((data = evbuffer_new()) == NULL) { + /* out of memory */ + goto error; + } + + /* serialize the reply */ + rpc->reply_marshal(data, rpc_state->reply); + + /* do hook based tweaks to the request */ + if (evrpc_process_hooks(&rpc->base->output_hooks, + req, data) == -1) + 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", data); + + evbuffer_free(data); + + evrpc_reqstate_free(rpc_state); + + return; + +error: + if (data != NULL) + evbuffer_free(data); + evrpc_reqstate_free(rpc_state); + evhttp_send_error(req, HTTP_SERVUNAVAIL, "Service Error"); + 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 = calloc(1, sizeof(struct evrpc_pool)); + if (pool == NULL) + return (NULL); + + TAILQ_INIT(&pool->connections); + TAILQ_INIT(&pool->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) +{ + free(request->name); + free(request); +} + +void +evrpc_pool_free(struct evrpc_pool *pool) +{ + struct evhttp_connection *connection; + struct evrpc_request_wrapper *request; + struct evrpc_hook *hook; + + while ((request = TAILQ_FIRST(&pool->requests)) != NULL) { + TAILQ_REMOVE(&pool->requests, request, next); + /* if this gets more complicated we need our own function */ + evrpc_request_wrapper_free(request); + } + + 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) { + assert(evrpc_remove_hook(pool, INPUT, hook)); + } + + while ((hook = TAILQ_FIRST(&pool->output_hooks)) != NULL) { + assert(evrpc_remove_hook(pool, OUTPUT, hook)); + } + + 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) { + 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 (connection->timeout == -1) + connection->timeout = 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_set_timeout(struct evrpc_pool *pool, int timeout_in_secs) +{ + struct evhttp_connection *evcon; + TAILQ_FOREACH(evcon, &pool->connections, next) { + evcon->timeout = timeout_in_secs; + } + pool->timeout = timeout_in_secs; +} + + +static void evrpc_reply_done(struct evhttp_request *, void *); +static void evrpc_request_timeout(int, 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); +} + +/* + * 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; + char *uri = NULL; + int res = 0; + + 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); + + uri = evrpc_construct_uri(ctx->name); + if (uri == NULL) + goto error; + + /* we need to know the connection that we might have to abort */ + ctx->evcon = connection; + + /* apply hooks to the outgoing request */ + if (evrpc_process_hooks(&pool->output_hooks, + req, req->output_buffer) == -1) + 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); + free(uri); + + if (res == -1) + goto error; + + 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); +} + +int +evrpc_make_request(struct evrpc_request_wrapper *ctx) +{ + struct evrpc_pool *pool = ctx->pool; + + /* initialize the event structure for this rpc */ + evtimer_set(&ctx->ev_timeout, evrpc_request_timeout, ctx); + if (pool->base != NULL) + event_base_set(pool->base, &ctx->ev_timeout); + + /* we better have some available connections on the pool */ + 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); +} + +static void +evrpc_reply_done(struct evhttp_request *req, void *arg) +{ + struct evrpc_request_wrapper *ctx = arg; + struct evrpc_pool *pool = ctx->pool; + struct evrpc_status status; + int res = -1; + + /* cancel any timeout we might have scheduled */ + event_del(&ctx->ev_timeout); + + memset(&status, 0, sizeof(status)); + status.http_req = req; + + /* we need to get the reply now */ + if (req != NULL) { + /* apply hooks to the incoming request */ + if (evrpc_process_hooks(&pool->input_hooks, + req, req->input_buffer) == -1) { + status.error = EVRPC_STATUS_ERR_HOOKABORTED; + res = -1; + } else { + res = ctx->reply_unmarshal(ctx->reply, + req->input_buffer); + if (res == -1) { + status.error = EVRPC_STATUS_ERR_BADPAYLOAD; + } + } + } else { + status.error = EVRPC_STATUS_ERR_TIMEOUT; + } + + 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 owns the request structure */ + + /* 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(int fd, short what, void *arg) +{ + struct evrpc_request_wrapper *ctx = arg; + struct evhttp_connection *evcon = ctx->evcon; + assert(evcon != NULL); + + evhttp_connection_fail(evcon, EVCON_HTTP_TIMEOUT); +} |