X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/4d776dba3c706aa20fd7d95dd73bff32dc2148a7..6255a5ae668a0aaf13d73f051face138cfbd78a4:/src/scripting.c diff --git a/src/scripting.c b/src/scripting.c index 255184e7..44ceb1e2 100644 --- a/src/scripting.c +++ b/src/scripting.c @@ -15,6 +15,7 @@ char *redisProtocolToLuaType_Error(lua_State *lua, char *reply); char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply); int redis_math_random (lua_State *L); int redis_math_randomseed (lua_State *L); +void sha1hex(char *digest, char *script, size_t len); /* Take a Redis reply in the Redis protocol format and convert it into a * Lua type. Thanks to this function, and the introduction of not connected @@ -27,7 +28,7 @@ int redis_math_randomseed (lua_State *L); * is like a normal client that bypasses all the slow I/O paths. * * Note: in this function we do not do any sanity check as the reply is - * generated by Redis directly. This allows use to go faster. + * generated by Redis directly. This allows us to go faster. * The reply string can be altered during the parsing as it is discared * after the conversion is completed. * @@ -128,6 +129,37 @@ void luaPushError(lua_State *lua, char *error) { lua_settable(lua,-3); } +/* Sort the array currently in the stack. We do this to make the output + * of commands like KEYS or SMEMBERS something deterministic when called + * from Lua (to play well with AOf/replication). + * + * The array is sorted using table.sort itself, and assuming all the + * list elements are strings. */ +void luaSortArray(lua_State *lua) { + /* Initial Stack: array */ + lua_getglobal(lua,"table"); + lua_pushstring(lua,"sort"); + lua_gettable(lua,-2); /* Stack: array, table, table.sort */ + lua_pushvalue(lua,-3); /* Stack: array, table, table.sort, array */ + if (lua_pcall(lua,1,0,0)) { + /* Stack: array, table, error */ + + /* We are not interested in the error, we assume that the problem is + * that there are 'false' elements inside the array, so we try + * again with a slower function but able to handle this case, that + * is: table.sort(table, __redis__compare_helper) */ + lua_pop(lua,1); /* Stack: array, table */ + lua_pushstring(lua,"sort"); /* Stack: array, table, sort */ + lua_gettable(lua,-2); /* Stack: array, table, table.sort */ + lua_pushvalue(lua,-3); /* Stack: array, table, table.sort, array */ + lua_getglobal(lua,"__redis__compare_helper"); + /* Stack: array, table, table.sort, array, __redis__compare_helper */ + lua_call(lua,2,0); + } + /* Stack: array (sorted), table */ + lua_pop(lua,1); /* Stack: array (sorted) */ +} + int luaRedisGenericCommand(lua_State *lua, int raise_error) { int j, argc = lua_gettop(lua); struct redisCommand *cmd; @@ -175,22 +207,53 @@ int luaRedisGenericCommand(lua_State *lua, int raise_error) { goto cleanup; } + /* There are commands that are not allowed inside scripts. */ if (cmd->flags & REDIS_CMD_NOSCRIPT) { luaPushError(lua, "This Redis command is not allowed from scripts"); goto cleanup; } - if (cmd->flags & REDIS_CMD_WRITE && server.lua_random_dirty) { - luaPushError(lua, - "Write commands not allowed after non deterministic commands"); - goto cleanup; + /* Write commands are forbidden against read-only slaves, or if a + * command marked as non-deterministic was already called in the context + * of this script. */ + if (cmd->flags & REDIS_CMD_WRITE) { + if (server.lua_random_dirty) { + luaPushError(lua, + "Write commands not allowed after non deterministic commands"); + goto cleanup; + } else if (server.masterhost && server.repl_slave_ro && + !(server.lua_caller->flags & REDIS_MASTER)) + { + luaPushError(lua, shared.roslaveerr->ptr); + goto cleanup; + } else if (server.stop_writes_on_bgsave_err && + server.saveparamslen > 0 && + server.lastbgsave_status == REDIS_ERR) + { + luaPushError(lua, shared.bgsaveerr->ptr); + goto cleanup; + } + } + + /* If we reached the memory limit configured via maxmemory, commands that + * could enlarge the memory usage are not allowed, but only if this is the + * first write in the context of this script, otherwise we can't stop + * in the middle. */ + if (server.maxmemory && server.lua_write_dirty == 0 && + (cmd->flags & REDIS_CMD_DENYOOM)) + { + if (freeMemoryIfNeeded() == REDIS_ERR) { + luaPushError(lua, shared.oomerr->ptr); + goto cleanup; + } } if (cmd->flags & REDIS_CMD_RANDOM) server.lua_random_dirty = 1; if (cmd->flags & REDIS_CMD_WRITE) server.lua_write_dirty = 1; /* Run the command */ - cmd->proc(c); + c->cmd = cmd; + call(c,REDIS_CALL_SLOWLOG | REDIS_CALL_STATS); /* Convert the result of the Redis command into a suitable Lua type. * The first thing we need is to create a single string from the client @@ -208,6 +271,14 @@ int luaRedisGenericCommand(lua_State *lua, int raise_error) { } if (raise_error && reply[0] != '-') raise_error = 0; redisProtocolToLuaType(lua,reply); + /* Sort the output array if needed, assuming it is a non-null multi bulk + * reply as expected. */ + if ((cmd->flags & REDIS_CMD_SORT_FOR_SCRIPT) && + (reply[0] == '*' && reply[1] != '-')) { + /* Skip this step if command is SORT but output was already sorted */ + if (cmd->proc != sortCommand || server.sort_dontsort) + luaSortArray(lua); + } sdsfree(reply); cleanup: @@ -236,6 +307,25 @@ int luaRedisPCallCommand(lua_State *lua) { return luaRedisGenericCommand(lua,0); } +/* This adds redis.sha1hex(string) to Lua scripts using the same hashing + * function used for sha1ing lua scripts. */ +int luaRedisSha1hexCommand(lua_State *lua) { + int argc = lua_gettop(lua); + char digest[41]; + size_t len; + char *s; + + if (argc != 1) { + luaPushError(lua, "wrong number of arguments"); + return 1; + } + + s = (char*)lua_tolstring(lua,1,&len); + sha1hex(digest,s,len); + lua_pushstring(lua,digest); + return 1; +} + int luaLogCommand(lua_State *lua) { int j, argc = lua_gettop(lua); int level; @@ -303,6 +393,8 @@ void luaLoadLib(lua_State *lua, const char *libname, lua_CFunction luafunc) { } LUALIB_API int (luaopen_cjson) (lua_State *L); +LUALIB_API int (luaopen_struct) (lua_State *L); +LUALIB_API int (luaopen_cmsgpack) (lua_State *L); void luaLoadLibraries(lua_State *lua) { luaLoadLib(lua, "", luaopen_base); @@ -310,7 +402,9 @@ void luaLoadLibraries(lua_State *lua) { luaLoadLib(lua, LUA_STRLIBNAME, luaopen_string); luaLoadLib(lua, LUA_MATHLIBNAME, luaopen_math); luaLoadLib(lua, LUA_DBLIBNAME, luaopen_debug); - luaLoadLib(lua, "cjson", luaopen_cjson); + luaLoadLib(lua, "cjson", luaopen_cjson); + luaLoadLib(lua, "struct", luaopen_struct); + luaLoadLib(lua, "cmsgpack", luaopen_cmsgpack); #if 0 /* Stuff that we don't load currently, for sandboxing concerns. */ luaLoadLib(lua, LUA_LOADLIBNAME, luaopen_package); @@ -318,6 +412,61 @@ void luaLoadLibraries(lua_State *lua) { #endif } +/* This function installs metamethods in the global table _G that prevent + * the creation of globals accidentally. + * + * It should be the last to be called in the scripting engine initialization + * sequence, because it may interact with creation of globals. + * Note that the function is designed to be called multiple times if needed + * without issues, because it is possible to enabled/disable globals protection + * at runtime with CONFIG SET. */ +void scriptingEnableGlobalsProtection(lua_State *lua) { + char *s[32]; + sds code = sdsempty(); + int j = 0; + + /* strict.lua from: http://metalua.luaforge.net/src/lib/strict.lua.html. + * Modified to be adapted to Redis. */ + s[j++]="local mt = {}\n"; + s[j++]="setmetatable(_G, mt)\n"; + s[j++]="mt.declared = {}\n"; + s[j++]="mt.__newindex = function (t, n, v)\n"; + s[j++]=" if not mt.declared[n] and debug.getinfo(2) then\n"; + s[j++]=" local w = debug.getinfo(2, \"S\").what\n"; + s[j++]=" if w ~= \"main\" and w ~= \"C\" then\n"; + s[j++]=" error(\"assignment to undeclared global variable '\"..n..\"'\", 2)\n"; + s[j++]=" end\n"; + s[j++]=" mt.declared[n] = true\n"; + s[j++]=" end\n"; + s[j++]=" rawset(t, n, v)\n"; + s[j++]="end\n"; + s[j++]="mt.__index = function (t, n)\n"; + s[j++]=" if debug.getinfo(2) and not mt.declared[n] and debug.getinfo(2, \"S\").what ~= \"C\" then\n"; + s[j++]=" error(\"global variable '\"..n..\"' is not declared\", 2)\n"; + s[j++]=" end\n"; + s[j++]=" return rawget(t, n)\n"; + s[j++]="end\n"; + s[j++]="function global(...)\n"; + s[j++]=" local nargs = select(\"#\",...)\n"; + s[j++]=" for i = 1, nargs do\n"; + s[j++]=" local v = select(i,...)\n"; + s[j++]=" mt.declared[v] = true\n"; + s[j++]=" end\n"; + s[j++]="end\n"; + s[j++]=NULL; + + for (j = 0; s[j] != NULL; j++) code = sdscatlen(code,s[j],strlen(s[j])); + luaL_loadbuffer(lua,code,sdslen(code),"enable_strict_lua"); + lua_pcall(lua,0,0,0); + sdsfree(code); +} + +void scriptingDisableGlobalsProtection(lua_State *lua) { + char *s = "setmetatable(_G, nil)\n"; + luaL_loadbuffer(lua,s,strlen(s),"disable_strict_lua"); + lua_pcall(lua,0,0,0); +} + /* Initialize the scripting environment. * It is possible to call this function to reset the scripting environment * assuming that we call scriptingRelease() before. @@ -365,6 +514,11 @@ void scriptingInit(void) { lua_pushnumber(lua,REDIS_WARNING); lua_settable(lua,-3); + /* redis.sha1hex */ + lua_pushstring(lua, "sha1hex"); + lua_pushcfunction(lua, luaRedisSha1hexCommand); + lua_settable(lua, -3); + /* Finally set the table as 'redis' global var. */ lua_setglobal(lua,"redis"); @@ -381,6 +535,18 @@ void scriptingInit(void) { lua_setglobal(lua,"math"); + /* Add a helper funciton that we use to sort the multi bulk output of non + * deterministic commands, when containing 'false' elements. */ + { + char *compare_func = "function __redis__compare_helper(a,b)\n" + " if a == false then a = '' end\n" + " if b == false then b = '' end\n" + " return aflags |= REDIS_LUA_CLIENT; } + /* Lua beginners ofter don't use "local", this is likely to introduce + * subtle bugs in their code. To prevent problems we protect accesses + * to global variables. */ + if (server.lua_protect_globals) + scriptingEnableGlobalsProtection(lua); + server.lua = lua; } @@ -405,10 +577,13 @@ void scriptingReset(void) { scriptingInit(); } -/* Hash the scripit into a SHA1 digest. We use this as Lua function name. - * Digest should point to a 41 bytes buffer: 40 for SHA1 converted into an +/* Perform the SHA1 of the input string. We use this both for hasing script + * bodies in order to obtain the Lua function name, and in the implementation + * of redis.sha1(). + * + * 'digest' should point to a 41 bytes buffer: 40 for SHA1 converted into an * hexadecimal number, plus 1 byte for null term. */ -void hashScript(char *digest, char *script, size_t len) { +void sha1hex(char *digest, char *script, size_t len) { SHA1_CTX ctx; unsigned char hash[20]; char *cset = "0123456789abcdef"; @@ -581,7 +756,7 @@ void evalGenericCommand(redisClient *c, int evalsha) { funcname[1] = '_'; if (!evalsha) { /* Hash the code if this is an EVAL call */ - hashScript(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr)); + sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr)); } else { /* We already have the SHA if it is a EVALSHA */ int j; @@ -755,7 +930,7 @@ void scriptCommand(redisClient *c) { funcname[0] = 'f'; funcname[1] = '_'; - hashScript(funcname+2,c->argv[2]->ptr,sdslen(c->argv[2]->ptr)); + sha1hex(funcname+2,c->argv[2]->ptr,sdslen(c->argv[2]->ptr)); sha = sdsnewlen(funcname+2,40); if (dictFind(server.lua_scripts,sha) == NULL) { if (luaCreateFunction(c,server.lua,funcname,c->argv[2])