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#include "redismodule.h"
#include <string.h>
static RedisModuleString *log_key_name;
static const char log_command_name[] = "commandfilter.log";
static const char ping_command_name[] = "commandfilter.ping";
static const char retained_command_name[] = "commandfilter.retained";
static const char unregister_command_name[] = "commandfilter.unregister";
static int in_log_command = 0;
static RedisModuleCommandFilter *filter, *filter1;
static RedisModuleString *retained;
int CommandFilter_UnregisterCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
{
(void) argc;
(void) argv;
RedisModule_ReplyWithLongLong(ctx,
RedisModule_UnregisterCommandFilter(ctx, filter));
return REDISMODULE_OK;
}
int CommandFilter_PingCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
{
(void) argc;
(void) argv;
RedisModuleCallReply *reply = RedisModule_Call(ctx, "ping", "c", "@log");
if (reply) {
RedisModule_ReplyWithCallReply(ctx, reply);
RedisModule_FreeCallReply(reply);
} else {
RedisModule_ReplyWithSimpleString(ctx, "Unknown command or invalid arguments");
}
return REDISMODULE_OK;
}
int CommandFilter_Retained(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
{
(void) argc;
(void) argv;
if (retained) {
RedisModule_ReplyWithString(ctx, retained);
} else {
RedisModule_ReplyWithNull(ctx);
}
return REDISMODULE_OK;
}
int CommandFilter_LogCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
{
RedisModuleString *s = RedisModule_CreateString(ctx, "", 0);
int i;
for (i = 1; i < argc; i++) {
size_t arglen;
const char *arg = RedisModule_StringPtrLen(argv[i], &arglen);
if (i > 1) RedisModule_StringAppendBuffer(ctx, s, " ", 1);
RedisModule_StringAppendBuffer(ctx, s, arg, arglen);
}
RedisModuleKey *log = RedisModule_OpenKey(ctx, log_key_name, REDISMODULE_WRITE|REDISMODULE_READ);
RedisModule_ListPush(log, REDISMODULE_LIST_HEAD, s);
RedisModule_CloseKey(log);
RedisModule_FreeString(ctx, s);
in_log_command = 1;
size_t cmdlen;
const char *cmdname = RedisModule_StringPtrLen(argv[1], &cmdlen);
RedisModuleCallReply *reply = RedisModule_Call(ctx, cmdname, "v", &argv[2], argc - 2);
if (reply) {
RedisModule_ReplyWithCallReply(ctx, reply);
RedisModule_FreeCallReply(reply);
} else {
RedisModule_ReplyWithSimpleString(ctx, "Unknown command or invalid arguments");
}
in_log_command = 0;
return REDISMODULE_OK;
}
/* Filter to protect against Bug #11894 reappearing
*
* ensures that the filter is only run the first time through, and not on reprocessing
*/
void CommandFilter_BlmoveSwap(RedisModuleCommandFilterCtx *filter)
{
if (RedisModule_CommandFilterArgsCount(filter) != 6)
return;
RedisModuleString *arg = RedisModule_CommandFilterArgGet(filter, 0);
size_t arg_len;
const char *arg_str = RedisModule_StringPtrLen(arg, &arg_len);
if (arg_len != 6 || strncmp(arg_str, "blmove", 6))
return;
/*
* Swapping directional args (right/left) from source and destination.
* need to hold here, can't push into the ArgReplace func, as it will cause other to freed -> use after free
*/
RedisModuleString *dir1 = RedisModule_HoldString(NULL, RedisModule_CommandFilterArgGet(filter, 3));
RedisModuleString *dir2 = RedisModule_HoldString(NULL, RedisModule_CommandFilterArgGet(filter, 4));
RedisModule_CommandFilterArgReplace(filter, 3, dir2);
RedisModule_CommandFilterArgReplace(filter, 4, dir1);
}
void CommandFilter_CommandFilter(RedisModuleCommandFilterCtx *filter)
{
if (in_log_command) return; /* don't process our own RM_Call() from CommandFilter_LogCommand() */
/* Fun manipulations:
* - Remove @delme
* - Replace @replaceme
* - Append @insertbefore or @insertafter
* - Prefix with Log command if @log encountered
*/
int log = 0;
int pos = 0;
while (pos < RedisModule_CommandFilterArgsCount(filter)) {
const RedisModuleString *arg = RedisModule_CommandFilterArgGet(filter, pos);
size_t arg_len;
const char *arg_str = RedisModule_StringPtrLen(arg, &arg_len);
if (arg_len == 6 && !memcmp(arg_str, "@delme", 6)) {
RedisModule_CommandFilterArgDelete(filter, pos);
continue;
}
if (arg_len == 10 && !memcmp(arg_str, "@replaceme", 10)) {
RedisModule_CommandFilterArgReplace(filter, pos,
RedisModule_CreateString(NULL, "--replaced--", 12));
} else if (arg_len == 13 && !memcmp(arg_str, "@insertbefore", 13)) {
RedisModule_CommandFilterArgInsert(filter, pos,
RedisModule_CreateString(NULL, "--inserted-before--", 19));
pos++;
} else if (arg_len == 12 && !memcmp(arg_str, "@insertafter", 12)) {
RedisModule_CommandFilterArgInsert(filter, pos + 1,
RedisModule_CreateString(NULL, "--inserted-after--", 18));
pos++;
} else if (arg_len == 7 && !memcmp(arg_str, "@retain", 7)) {
if (retained) RedisModule_FreeString(NULL, retained);
retained = RedisModule_CommandFilterArgGet(filter, pos + 1);
RedisModule_RetainString(NULL, retained);
pos++;
} else if (arg_len == 4 && !memcmp(arg_str, "@log", 4)) {
log = 1;
}
pos++;
}
if (log) RedisModule_CommandFilterArgInsert(filter, 0,
RedisModule_CreateString(NULL, log_command_name, sizeof(log_command_name)-1));
}
int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
if (RedisModule_Init(ctx,"commandfilter",1,REDISMODULE_APIVER_1)
== REDISMODULE_ERR) return REDISMODULE_ERR;
if (argc != 2) {
RedisModule_Log(ctx, "warning", "Log key name not specified");
return REDISMODULE_ERR;
}
long long noself = 0;
log_key_name = RedisModule_CreateStringFromString(ctx, argv[0]);
RedisModule_StringToLongLong(argv[1], &noself);
retained = NULL;
if (RedisModule_CreateCommand(ctx,log_command_name,
CommandFilter_LogCommand,"write deny-oom",1,1,1) == REDISMODULE_ERR)
return REDISMODULE_ERR;
if (RedisModule_CreateCommand(ctx,ping_command_name,
CommandFilter_PingCommand,"deny-oom",1,1,1) == REDISMODULE_ERR)
return REDISMODULE_ERR;
if (RedisModule_CreateCommand(ctx,retained_command_name,
CommandFilter_Retained,"readonly",1,1,1) == REDISMODULE_ERR)
return REDISMODULE_ERR;
if (RedisModule_CreateCommand(ctx,unregister_command_name,
CommandFilter_UnregisterCommand,"write deny-oom",1,1,1) == REDISMODULE_ERR)
return REDISMODULE_ERR;
if ((filter = RedisModule_RegisterCommandFilter(ctx, CommandFilter_CommandFilter,
noself ? REDISMODULE_CMDFILTER_NOSELF : 0))
== NULL) return REDISMODULE_ERR;
if ((filter1 = RedisModule_RegisterCommandFilter(ctx, CommandFilter_BlmoveSwap, 0)) == NULL)
return REDISMODULE_ERR;
return REDISMODULE_OK;
}
int RedisModule_OnUnload(RedisModuleCtx *ctx) {
RedisModule_FreeString(ctx, log_key_name);
if (retained) RedisModule_FreeString(NULL, retained);
return REDISMODULE_OK;
}
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