1 #define REDISMODULE_EXPERIMENTAL_API
2 #include "redismodule.h"
3
4 #include <string.h>
5
6 static RedisModuleString *log_key_name;
7
8 static const char log_command_name[] = "commandfilter.log";
9 static const char ping_command_name[] = "commandfilter.ping";
10 static const char unregister_command_name[] = "commandfilter.unregister";
11 static int in_log_command = 0;
12
13 static RedisModuleCommandFilter *filter = NULL;
14
CommandFilter_UnregisterCommand(RedisModuleCtx * ctx,RedisModuleString ** argv,int argc)15 int CommandFilter_UnregisterCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
16 {
17 (void) argc;
18 (void) argv;
19
20 RedisModule_ReplyWithLongLong(ctx,
21 RedisModule_UnregisterCommandFilter(ctx, filter));
22
23 return REDISMODULE_OK;
24 }
25
CommandFilter_PingCommand(RedisModuleCtx * ctx,RedisModuleString ** argv,int argc)26 int CommandFilter_PingCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
27 {
28 (void) argc;
29 (void) argv;
30
31 RedisModuleCallReply *reply = RedisModule_Call(ctx, "ping", "c", "@log");
32 if (reply) {
33 RedisModule_ReplyWithCallReply(ctx, reply);
34 RedisModule_FreeCallReply(reply);
35 } else {
36 RedisModule_ReplyWithSimpleString(ctx, "Unknown command or invalid arguments");
37 }
38
39 return REDISMODULE_OK;
40 }
41
CommandFilter_LogCommand(RedisModuleCtx * ctx,RedisModuleString ** argv,int argc)42 int CommandFilter_LogCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
43 {
44 RedisModuleString *s = RedisModule_CreateString(ctx, "", 0);
45
46 int i;
47 for (i = 1; i < argc; i++) {
48 size_t arglen;
49 const char *arg = RedisModule_StringPtrLen(argv[i], &arglen);
50
51 if (i > 1) RedisModule_StringAppendBuffer(ctx, s, " ", 1);
52 RedisModule_StringAppendBuffer(ctx, s, arg, arglen);
53 }
54
55 RedisModuleKey *log = RedisModule_OpenKey(ctx, log_key_name, REDISMODULE_WRITE|REDISMODULE_READ);
56 RedisModule_ListPush(log, REDISMODULE_LIST_HEAD, s);
57 RedisModule_CloseKey(log);
58 RedisModule_FreeString(ctx, s);
59
60 in_log_command = 1;
61
62 size_t cmdlen;
63 const char *cmdname = RedisModule_StringPtrLen(argv[1], &cmdlen);
64 RedisModuleCallReply *reply = RedisModule_Call(ctx, cmdname, "v", &argv[2], argc - 2);
65 if (reply) {
66 RedisModule_ReplyWithCallReply(ctx, reply);
67 RedisModule_FreeCallReply(reply);
68 } else {
69 RedisModule_ReplyWithSimpleString(ctx, "Unknown command or invalid arguments");
70 }
71
72 in_log_command = 0;
73
74 return REDISMODULE_OK;
75 }
76
CommandFilter_CommandFilter(RedisModuleCommandFilterCtx * filter)77 void CommandFilter_CommandFilter(RedisModuleCommandFilterCtx *filter)
78 {
79 if (in_log_command) return; /* don't process our own RM_Call() from CommandFilter_LogCommand() */
80
81 /* Fun manipulations:
82 * - Remove @delme
83 * - Replace @replaceme
84 * - Append @insertbefore or @insertafter
85 * - Prefix with Log command if @log encounterd
86 */
87 int log = 0;
88 int pos = 0;
89 while (pos < RedisModule_CommandFilterArgsCount(filter)) {
90 const RedisModuleString *arg = RedisModule_CommandFilterArgGet(filter, pos);
91 size_t arg_len;
92 const char *arg_str = RedisModule_StringPtrLen(arg, &arg_len);
93
94 if (arg_len == 6 && !memcmp(arg_str, "@delme", 6)) {
95 RedisModule_CommandFilterArgDelete(filter, pos);
96 continue;
97 }
98 if (arg_len == 10 && !memcmp(arg_str, "@replaceme", 10)) {
99 RedisModule_CommandFilterArgReplace(filter, pos,
100 RedisModule_CreateString(NULL, "--replaced--", 12));
101 } else if (arg_len == 13 && !memcmp(arg_str, "@insertbefore", 13)) {
102 RedisModule_CommandFilterArgInsert(filter, pos,
103 RedisModule_CreateString(NULL, "--inserted-before--", 19));
104 pos++;
105 } else if (arg_len == 12 && !memcmp(arg_str, "@insertafter", 12)) {
106 RedisModule_CommandFilterArgInsert(filter, pos + 1,
107 RedisModule_CreateString(NULL, "--inserted-after--", 18));
108 pos++;
109 } else if (arg_len == 4 && !memcmp(arg_str, "@log", 4)) {
110 log = 1;
111 }
112 pos++;
113 }
114
115 if (log) RedisModule_CommandFilterArgInsert(filter, 0,
116 RedisModule_CreateString(NULL, log_command_name, sizeof(log_command_name)-1));
117 }
118
RedisModule_OnLoad(RedisModuleCtx * ctx,RedisModuleString ** argv,int argc)119 int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
120 if (RedisModule_Init(ctx,"commandfilter",1,REDISMODULE_APIVER_1)
121 == REDISMODULE_ERR) return REDISMODULE_ERR;
122
123 if (argc != 2) {
124 RedisModule_Log(ctx, "warning", "Log key name not specified");
125 return REDISMODULE_ERR;
126 }
127
128 long long noself = 0;
129 log_key_name = RedisModule_CreateStringFromString(ctx, argv[0]);
130 RedisModule_StringToLongLong(argv[1], &noself);
131
132 if (RedisModule_CreateCommand(ctx,log_command_name,
133 CommandFilter_LogCommand,"write deny-oom",1,1,1) == REDISMODULE_ERR)
134 return REDISMODULE_ERR;
135
136 if (RedisModule_CreateCommand(ctx,ping_command_name,
137 CommandFilter_PingCommand,"deny-oom",1,1,1) == REDISMODULE_ERR)
138 return REDISMODULE_ERR;
139
140 if (RedisModule_CreateCommand(ctx,unregister_command_name,
141 CommandFilter_UnregisterCommand,"write deny-oom",1,1,1) == REDISMODULE_ERR)
142 return REDISMODULE_ERR;
143
144 if ((filter = RedisModule_RegisterCommandFilter(ctx, CommandFilter_CommandFilter,
145 noself ? REDISMODULE_CMDFILTER_NOSELF : 0))
146 == NULL) return REDISMODULE_ERR;
147
148 return REDISMODULE_OK;
149 }
150