1 /* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <string.h>
5
6 #include "protocol_extension.h"
7
8 /*
9 * This is an example on how you can add your own commands into the
10 * ascii protocol. You load the extensions into memcached by using
11 * the -X option:
12 * ./memcached -X .libs/example_protocol.so -E .libs/default_engine.so
13 *
14 * @todo add an example that require extra userspace data, and communicates
15 * with the engine by getting the engine descriptor.
16 */
17
18 static const char *get_name(const void *cmd_cookie);
19 static bool accept_command(const void *cmd_cookie, void *cookie,
20 int argc, token_t *argv, size_t *ndata,
21 char **ptr);
22 static ENGINE_ERROR_CODE execute_command(const void *cmd_cookie, const void *cookie,
23 int argc, token_t *argv,
24 ENGINE_ERROR_CODE (*response_handler)(const void *cookie,
25 int nbytes,
26 const char *dta));
27 static void abort_command(const void *cmd_cookie, const void *cookie);
28
29 static EXTENSION_ASCII_PROTOCOL_DESCRIPTOR noop_descriptor = {
30 .get_name = get_name,
31 .accept = accept_command,
32 .execute = execute_command,
33 .abort = abort_command,
34 .cookie = &noop_descriptor
35 };
36
37 static EXTENSION_ASCII_PROTOCOL_DESCRIPTOR echo_descriptor = {
38 .get_name = get_name,
39 .accept = accept_command,
40 .execute = execute_command,
41 .abort = abort_command,
42 .cookie = &echo_descriptor
43 };
44
get_name(const void * cmd_cookie)45 static const char *get_name(const void *cmd_cookie) {
46 if (cmd_cookie == &noop_descriptor) {
47 return "noop";
48 } else {
49 return "echo";
50 }
51 }
52
accept_command(const void * cmd_cookie,void * cookie,int argc,token_t * argv,size_t * ndata,char ** ptr)53 static bool accept_command(const void *cmd_cookie, void *cookie,
54 int argc, token_t *argv, size_t *ndata,
55 char **ptr) {
56 if (cmd_cookie == &noop_descriptor) {
57 return strcmp(argv[0].value, "noop") == 0;
58 } else {
59 return strcmp(argv[0].value, "echo") == 0;
60 }
61 }
62
execute_command(const void * cmd_cookie,const void * cookie,int argc,token_t * argv,ENGINE_ERROR_CODE (* response_handler)(const void * cookie,int nbytes,const char * dta))63 static ENGINE_ERROR_CODE execute_command(const void *cmd_cookie, const void *cookie,
64 int argc, token_t *argv,
65 ENGINE_ERROR_CODE (*response_handler)(const void *cookie,
66 int nbytes,
67 const char *dta))
68 {
69 if (cmd_cookie == &noop_descriptor) {
70 return response_handler(cookie, 4, "OK\r\n");
71 } else {
72 if (response_handler(cookie, argv[0].length, argv[0].value) != ENGINE_SUCCESS) {
73 return ENGINE_DISCONNECT;
74 }
75
76 for (int ii = 1; ii < argc; ++ii) {
77 if (response_handler(cookie, 2, " [") != ENGINE_SUCCESS ||
78 response_handler(cookie, argv[ii].length, argv[ii].value) != ENGINE_SUCCESS ||
79 response_handler(cookie, 1, "]") != ENGINE_SUCCESS) {
80 return ENGINE_DISCONNECT;
81 }
82 }
83
84 return response_handler(cookie, 2, "\r\n");
85 }
86 }
87
abort_command(const void * cmd_cookie,const void * cookie)88 static void abort_command(const void *cmd_cookie, const void *cookie)
89 {
90 /* EMPTY */
91 }
92
93 #if defined (__SUNPRO_C) && (__SUNPRO_C >= 0x550)
94 __global
95 #elif defined __GNUC__
96 __attribute__ ((visibility("default")))
97 #endif
memcached_extensions_initialize(const char * config,GET_SERVER_API get_server_api)98 EXTENSION_ERROR_CODE memcached_extensions_initialize(const char *config,
99 GET_SERVER_API get_server_api) {
100 SERVER_HANDLE_V1 *server = get_server_api();
101 if (server == NULL) {
102 return EXTENSION_FATAL;
103 }
104 if (!server->extension->register_extension(EXTENSION_ASCII_PROTOCOL,
105 &noop_descriptor)) {
106 return EXTENSION_FATAL;
107 }
108
109 if (!server->extension->register_extension(EXTENSION_ASCII_PROTOCOL,
110 &echo_descriptor)) {
111 return EXTENSION_FATAL;
112 }
113
114 return EXTENSION_SUCCESS;
115 }
116