| #include "starboard/memory.h" |
| /* |
| * Copyright (c) 2006 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. |
| */ |
| #ifndef _EVRPC_H_ |
| #define _EVRPC_H_ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** @file evrpc.h |
| * |
| * This header files provides basic support for an RPC server and client. |
| * |
| * To support RPCs in a server, every supported RPC command needs to be |
| * defined and registered. |
| * |
| * EVRPC_HEADER(SendCommand, Request, Reply); |
| * |
| * SendCommand is the name of the RPC command. |
| * Request is the name of a structure generated by event_rpcgen.py. |
| * It contains all parameters relating to the SendCommand RPC. The |
| * server needs to fill in the Reply structure. |
| * Reply is the name of a structure generated by event_rpcgen.py. It |
| * contains the answer to the RPC. |
| * |
| * To register an RPC with an HTTP server, you need to first create an RPC |
| * base with: |
| * |
| * struct evrpc_base *base = evrpc_init(http); |
| * |
| * A specific RPC can then be registered with |
| * |
| * EVRPC_REGISTER(base, SendCommand, Request, Reply, FunctionCB, arg); |
| * |
| * when the server receives an appropriately formatted RPC, the user callback |
| * is invokved. The callback needs to fill in the reply structure. |
| * |
| * void FunctionCB(EVRPC_STRUCT(SendCommand)* rpc, void *arg); |
| * |
| * To send the reply, call EVRPC_REQUEST_DONE(rpc); |
| * |
| * See the regression test for an example. |
| */ |
| |
| struct evbuffer; |
| struct event_base; |
| struct evrpc_req_generic; |
| |
| /* Encapsulates a request */ |
| struct evrpc { |
| TAILQ_ENTRY(evrpc) next; |
| |
| /* the URI at which the request handler lives */ |
| const char* uri; |
| |
| /* creates a new request structure */ |
| void *(*request_new)(void); |
| |
| /* frees the request structure */ |
| void (*request_free)(void *); |
| |
| /* unmarshals the buffer into the proper request structure */ |
| int (*request_unmarshal)(void *, struct evbuffer *); |
| |
| /* creates a new reply structure */ |
| void *(*reply_new)(void); |
| |
| /* creates a new reply structure */ |
| void (*reply_free)(void *); |
| |
| /* verifies that the reply is valid */ |
| int (*reply_complete)(void *); |
| |
| /* marshals the reply into a buffer */ |
| void (*reply_marshal)(struct evbuffer*, void *); |
| |
| /* the callback invoked for each received rpc */ |
| void (*cb)(struct evrpc_req_generic *, void *); |
| void *cb_arg; |
| |
| /* reference for further configuration */ |
| struct evrpc_base *base; |
| }; |
| |
| /** The type of a specific RPC Message |
| * |
| * @param rpcname the name of the RPC message |
| */ |
| #define EVRPC_STRUCT(rpcname) struct evrpc_req__##rpcname |
| |
| struct evhttp_request; |
| struct evrpc_status; |
| |
| /* We alias the RPC specific structs to this voided one */ |
| struct evrpc_req_generic { |
| /* the unmarshaled request object */ |
| void *request; |
| |
| /* the empty reply object that needs to be filled in */ |
| void *reply; |
| |
| /* |
| * the static structure for this rpc; that can be used to |
| * automatically unmarshal and marshal the http buffers. |
| */ |
| struct evrpc *rpc; |
| |
| /* |
| * the http request structure on which we need to answer. |
| */ |
| struct evhttp_request* http_req; |
| |
| /* |
| * callback to reply and finish answering this rpc |
| */ |
| void (*done)(struct evrpc_req_generic* rpc); |
| }; |
| |
| /** Creates the definitions and prototypes for an RPC |
| * |
| * You need to use EVRPC_HEADER to create structures and function prototypes |
| * needed by the server and client implementation. The structures have to be |
| * defined in an .rpc file and converted to source code via event_rpcgen.py |
| * |
| * @param rpcname the name of the RPC |
| * @param reqstruct the name of the RPC request structure |
| * @param replystruct the name of the RPC reply structure |
| * @see EVRPC_GENERATE() |
| */ |
| #define EVRPC_HEADER(rpcname, reqstruct, rplystruct) \ |
| EVRPC_STRUCT(rpcname) { \ |
| struct reqstruct* request; \ |
| struct rplystruct* reply; \ |
| struct evrpc* rpc; \ |
| struct evhttp_request* http_req; \ |
| void (*done)(struct evrpc_status *, \ |
| struct evrpc* rpc, void *request, void *reply); \ |
| }; \ |
| int evrpc_send_request_##rpcname(struct evrpc_pool *, \ |
| struct reqstruct *, struct rplystruct *, \ |
| void (*)(struct evrpc_status *, \ |
| struct reqstruct *, struct rplystruct *, void *cbarg), \ |
| void *); |
| |
| /** Generates the code for receiving and sending an RPC message |
| * |
| * EVRPC_GENERATE is used to create the code corresponding to sending |
| * and receiving a particular RPC message |
| * |
| * @param rpcname the name of the RPC |
| * @param reqstruct the name of the RPC request structure |
| * @param replystruct the name of the RPC reply structure |
| * @see EVRPC_HEADER() |
| */ |
| #define EVRPC_GENERATE(rpcname, reqstruct, rplystruct) \ |
| int evrpc_send_request_##rpcname( \ |
| struct evrpc_pool* pool, struct reqstruct* request, \ |
| struct rplystruct* reply, \ |
| void (*cb)(struct evrpc_status*, struct reqstruct*, struct rplystruct*, \ |
| void* cbarg), \ |
| void* cbarg) { \ |
| struct evrpc_status status; \ |
| struct evrpc_request_wrapper* ctx; \ |
| ctx = (struct evrpc_request_wrapper*)SbMemoryAllocate( \ |
| sizeof(struct evrpc_request_wrapper)); \ |
| if (ctx == NULL) \ |
| goto error; \ |
| ctx->pool = pool; \ |
| ctx->evcon = NULL; \ |
| ctx->name = strdup(#rpcname); \ |
| if (ctx->name == NULL) { \ |
| SbMemoryDeallocate(ctx); \ |
| goto error; \ |
| } \ |
| ctx->cb = (void (*)(struct evrpc_status*, void*, void*, void*))cb; \ |
| ctx->cb_arg = cbarg; \ |
| ctx->request = (void*)request; \ |
| ctx->reply = (void*)reply; \ |
| ctx->request_marshal = \ |
| (void (*)(struct evbuffer*, void*))reqstruct##_marshal; \ |
| ctx->reply_clear = (void (*)(void*))rplystruct##_clear; \ |
| ctx->reply_unmarshal = \ |
| (int (*)(void*, struct evbuffer*))rplystruct##_unmarshal; \ |
| return (evrpc_make_request(ctx)); \ |
| error: \ |
| memset(&status, 0, sizeof(status)); \ |
| status.error = EVRPC_STATUS_ERR_UNSTARTED; \ |
| (*(cb))(&status, request, reply, cbarg); \ |
| return (-1); \ |
| } |
| |
| /** Provides access to the HTTP request object underlying an RPC |
| * |
| * Access to the underlying http object; can be used to look at headers or |
| * for getting the remote ip address |
| * |
| * @param rpc_req the rpc request structure provided to the server callback |
| * @return an struct evhttp_request object that can be inspected for |
| * HTTP headers or sender information. |
| */ |
| #define EVRPC_REQUEST_HTTP(rpc_req) (rpc_req)->http_req |
| |
| /** Creates the reply to an RPC request |
| * |
| * EVRPC_REQUEST_DONE is used to answer a request; the reply is expected |
| * to have been filled in. The request and reply pointers become invalid |
| * after this call has finished. |
| * |
| * @param rpc_req the rpc request structure provided to the server callback |
| */ |
| #define EVRPC_REQUEST_DONE(rpc_req) do { \ |
| struct evrpc_req_generic *_req = (struct evrpc_req_generic *)(rpc_req); \ |
| _req->done(_req); \ |
| } while (0) |
| |
| |
| /* Takes a request object and fills it in with the right magic */ |
| #define EVRPC_REGISTER_OBJECT(rpc, name, request, reply) \ |
| do { \ |
| (rpc)->uri = strdup(#name); \ |
| if ((rpc)->uri == NULL) { \ |
| fprintf(stderr, "failed to register object\n"); \ |
| exit(1); \ |
| } \ |
| (rpc)->request_new = (void *(*)(void))request##_new; \ |
| (rpc)->request_free = (void (*)(void *))request##_free; \ |
| (rpc)->request_unmarshal = (int (*)(void *, struct evbuffer *))request##_unmarshal; \ |
| (rpc)->reply_new = (void *(*)(void))reply##_new; \ |
| (rpc)->reply_free = (void (*)(void *))reply##_free; \ |
| (rpc)->reply_complete = (int (*)(void *))reply##_complete; \ |
| (rpc)->reply_marshal = (void (*)(struct evbuffer*, void *))reply##_marshal; \ |
| } while (0) |
| |
| struct evrpc_base; |
| struct evhttp; |
| |
| /* functions to start up the rpc system */ |
| |
| /** Creates a new rpc base from which RPC requests can be received |
| * |
| * @param server a pointer to an existing HTTP server |
| * @return a newly allocated evrpc_base struct |
| * @see evrpc_free() |
| */ |
| struct evrpc_base *evrpc_init(struct evhttp *server); |
| |
| /** |
| * Frees the evrpc base |
| * |
| * For now, you are responsible for making sure that no rpcs are ongoing. |
| * |
| * @param base the evrpc_base object to be freed |
| * @see evrpc_init |
| */ |
| void evrpc_free(struct evrpc_base *base); |
| |
| /** register RPCs with the HTTP Server |
| * |
| * registers a new RPC with the HTTP server, each RPC needs to have |
| * a unique name under which it can be identified. |
| * |
| * @param base the evrpc_base structure in which the RPC should be |
| * registered. |
| * @param name the name of the RPC |
| * @param request the name of the RPC request structure |
| * @param reply the name of the RPC reply structure |
| * @param callback the callback that should be invoked when the RPC |
| * is received. The callback has the following prototype |
| * void (*callback)(EVRPC_STRUCT(Message)* rpc, void *arg) |
| * @param cbarg an additional parameter that can be passed to the callback. |
| * The parameter can be used to carry around state. |
| */ |
| #define EVRPC_REGISTER(base, name, request, reply, callback, cbarg) \ |
| do { \ |
| struct evrpc* rpc = (struct evrpc *)calloc(1, sizeof(struct evrpc)); \ |
| EVRPC_REGISTER_OBJECT(rpc, name, request, reply); \ |
| evrpc_register_rpc(base, rpc, \ |
| (void (*)(struct evrpc_req_generic*, void *))callback, cbarg); \ |
| } while (0) |
| |
| int evrpc_register_rpc(struct evrpc_base *, struct evrpc *, |
| void (*)(struct evrpc_req_generic*, void *), void *); |
| |
| /** |
| * Unregisters an already registered RPC |
| * |
| * @param base the evrpc_base object from which to unregister an RPC |
| * @param name the name of the rpc to unregister |
| * @return -1 on error or 0 when successful. |
| * @see EVRPC_REGISTER() |
| */ |
| #define EVRPC_UNREGISTER(base, name) evrpc_unregister_rpc(base, #name) |
| |
| int evrpc_unregister_rpc(struct evrpc_base *base, const char *name); |
| |
| /* |
| * Client-side RPC support |
| */ |
| |
| struct evrpc_pool; |
| struct evhttp_connection; |
| |
| /** |
| * provides information about the completed RPC request. |
| */ |
| struct evrpc_status { |
| #define EVRPC_STATUS_ERR_NONE 0 |
| #define EVRPC_STATUS_ERR_TIMEOUT 1 |
| #define EVRPC_STATUS_ERR_BADPAYLOAD 2 |
| #define EVRPC_STATUS_ERR_UNSTARTED 3 |
| #define EVRPC_STATUS_ERR_HOOKABORTED 4 |
| int error; |
| |
| /* for looking at headers or other information */ |
| struct evhttp_request *http_req; |
| }; |
| |
| struct evrpc_request_wrapper { |
| TAILQ_ENTRY(evrpc_request_wrapper) next; |
| |
| /* pool on which this rpc request is being made */ |
| struct evrpc_pool *pool; |
| |
| /* connection on which the request is being sent */ |
| struct evhttp_connection *evcon; |
| |
| /* event for implementing request timeouts */ |
| struct event ev_timeout; |
| |
| /* the name of the rpc */ |
| char *name; |
| |
| /* callback */ |
| void (*cb)(struct evrpc_status*, void *request, void *reply, void *arg); |
| void *cb_arg; |
| |
| void *request; |
| void *reply; |
| |
| /* unmarshals the buffer into the proper request structure */ |
| void (*request_marshal)(struct evbuffer *, void *); |
| |
| /* removes all stored state in the reply */ |
| void (*reply_clear)(void *); |
| |
| /* marshals the reply into a buffer */ |
| int (*reply_unmarshal)(void *, struct evbuffer*); |
| }; |
| |
| /** launches an RPC and sends it to the server |
| * |
| * EVRPC_MAKE_REQUEST() is used by the client to send an RPC to the server. |
| * |
| * @param name the name of the RPC |
| * @param pool the evrpc_pool that contains the connection objects over which |
| * the request should be sent. |
| * @param request a pointer to the RPC request structure - it contains the |
| * data to be sent to the server. |
| * @param reply a pointer to the RPC reply structure. It is going to be filled |
| * if the request was answered successfully |
| * @param cb the callback to invoke when the RPC request has been answered |
| * @param cbarg an additional argument to be passed to the client |
| * @return 0 on success, -1 on failure |
| */ |
| #define EVRPC_MAKE_REQUEST(name, pool, request, reply, cb, cbarg) \ |
| evrpc_send_request_##name(pool, request, reply, cb, cbarg) |
| |
| int evrpc_make_request(struct evrpc_request_wrapper *); |
| |
| /** creates an rpc connection pool |
| * |
| * a pool has a number of connections associated with it. |
| * rpc requests are always made via a pool. |
| * |
| * @param base a pointer to an struct event_based object; can be left NULL |
| * in singled-threaded applications |
| * @return a newly allocated struct evrpc_pool object |
| * @see evrpc_pool_free() |
| */ |
| struct evrpc_pool *evrpc_pool_new(struct event_base *base); |
| /** frees an rpc connection pool |
| * |
| * @param pool a pointer to an evrpc_pool allocated via evrpc_pool_new() |
| * @see evrpc_pool_new() |
| */ |
| void evrpc_pool_free(struct evrpc_pool *pool); |
| /* |
| * adds a connection over which rpc can be dispatched. the connection |
| * object must have been newly created. |
| */ |
| void evrpc_pool_add_connection(struct evrpc_pool *, |
| struct evhttp_connection *); |
| |
| /** |
| * Sets the timeout in secs after which a request has to complete. The |
| * RPC is completely aborted if it does not complete by then. Setting |
| * the timeout to 0 means that it never timeouts and can be used to |
| * implement callback type RPCs. |
| * |
| * Any connection already in the pool will be updated with the new |
| * timeout. Connections added to the pool after set_timeout has be |
| * called receive the pool timeout only if no timeout has been set |
| * for the connection itself. |
| * |
| * @param pool a pointer to a struct evrpc_pool object |
| * @param timeout_in_secs the number of seconds after which a request should |
| * timeout and a failure be returned to the callback. |
| */ |
| void evrpc_pool_set_timeout(struct evrpc_pool *pool, int timeout_in_secs); |
| |
| /** |
| * Hooks for changing the input and output of RPCs; this can be used to |
| * implement compression, authentication, encryption, ... |
| */ |
| |
| enum EVRPC_HOOK_TYPE { |
| EVRPC_INPUT, /**< apply the function to an input hook */ |
| EVRPC_OUTPUT /**< apply the function to an output hook */ |
| }; |
| |
| #ifndef WIN32 |
| /** Deprecated alias for EVRPC_INPUT. Not available on windows, where it |
| * conflicts with platform headers. */ |
| #define INPUT EVRPC_INPUT |
| /** Deprecated alias for EVRPC_OUTPUT. Not available on windows, where it |
| * conflicts with platform headers. */ |
| #define OUTPUT EVRPC_OUTPUT |
| #endif |
| |
| /** adds a processing hook to either an rpc base or rpc pool |
| * |
| * If a hook returns -1, the processing is aborted. |
| * |
| * The add functions return handles that can be used for removing hooks. |
| * |
| * @param vbase a pointer to either struct evrpc_base or struct evrpc_pool |
| * @param hook_type either INPUT or OUTPUT |
| * @param cb the callback to call when the hook is activated |
| * @param cb_arg an additional argument for the callback |
| * @return a handle to the hook so it can be removed later |
| * @see evrpc_remove_hook() |
| */ |
| void *evrpc_add_hook(void *vbase, |
| enum EVRPC_HOOK_TYPE hook_type, |
| int (*cb)(struct evhttp_request *, struct evbuffer *, void *), |
| void *cb_arg); |
| |
| /** removes a previously added hook |
| * |
| * @param vbase a pointer to either struct evrpc_base or struct evrpc_pool |
| * @param hook_type either INPUT or OUTPUT |
| * @param handle a handle returned by evrpc_add_hook() |
| * @return 1 on success or 0 on failure |
| * @see evrpc_add_hook() |
| */ |
| int evrpc_remove_hook(void *vbase, |
| enum EVRPC_HOOK_TYPE hook_type, |
| void *handle); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* _EVRPC_H_ */ |
