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scripting.c
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1158 lines (1025 loc) · 40.5 KB
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/*
* Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
#include "redis.h"
#include "sha1.h"
#include "rand.h"
#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>
#include <ctype.h>
#include <math.h>
char *redisProtocolToLuaType_Int(lua_State *lua, char *reply);
char *redisProtocolToLuaType_Bulk(lua_State *lua, char *reply);
char *redisProtocolToLuaType_Status(lua_State *lua, char *reply);
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
* clients, it is trivial to implement the redis() lua function.
*
* Basically we take the arguments, execute the Redis command in the context
* of a non connected client, then take the generated reply and convert it
* into a suitable Lua type. With this trick the scripting feature does not
* need the introduction of a full Redis internals API. Basically the script
* 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 us to go faster.
* The reply string can be altered during the parsing as it is discarded
* after the conversion is completed.
*
* Errors are returned as a table with a single 'err' field set to the
* error string.
*/
char *redisProtocolToLuaType(lua_State *lua, char* reply) {
char *p = reply;
switch(*p) {
case ':':
p = redisProtocolToLuaType_Int(lua,reply);
break;
case '$':
p = redisProtocolToLuaType_Bulk(lua,reply);
break;
case '+':
p = redisProtocolToLuaType_Status(lua,reply);
break;
case '-':
p = redisProtocolToLuaType_Error(lua,reply);
break;
case '*':
p = redisProtocolToLuaType_MultiBulk(lua,reply);
break;
}
return p;
}
char *redisProtocolToLuaType_Int(lua_State *lua, char *reply) {
char *p = strchr(reply+1,'\r');
long long value;
string2ll(reply+1,p-reply-1,&value);
lua_pushnumber(lua,(lua_Number)value);
return p+2;
}
char *redisProtocolToLuaType_Bulk(lua_State *lua, char *reply) {
char *p = strchr(reply+1,'\r');
long long bulklen;
string2ll(reply+1,p-reply-1,&bulklen);
if (bulklen == -1) {
lua_pushboolean(lua,0);
return p+2;
} else {
lua_pushlstring(lua,p+2,bulklen);
return p+2+bulklen+2;
}
}
char *redisProtocolToLuaType_Status(lua_State *lua, char *reply) {
char *p = strchr(reply+1,'\r');
lua_newtable(lua);
lua_pushstring(lua,"ok");
lua_pushlstring(lua,reply+1,p-reply-1);
lua_settable(lua,-3);
return p+2;
}
char *redisProtocolToLuaType_Error(lua_State *lua, char *reply) {
char *p = strchr(reply+1,'\r');
lua_newtable(lua);
lua_pushstring(lua,"err");
lua_pushlstring(lua,reply+1,p-reply-1);
lua_settable(lua,-3);
return p+2;
}
char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply) {
char *p = strchr(reply+1,'\r');
long long mbulklen;
int j = 0;
string2ll(reply+1,p-reply-1,&mbulklen);
p += 2;
if (mbulklen == -1) {
lua_pushboolean(lua,0);
return p;
}
lua_newtable(lua);
for (j = 0; j < mbulklen; j++) {
lua_pushnumber(lua,j+1);
p = redisProtocolToLuaType(lua,p);
lua_settable(lua,-3);
}
return p;
}
void luaPushError(lua_State *lua, char *error) {
lua_Debug dbg;
lua_newtable(lua);
lua_pushstring(lua,"err");
/* Attempt to figure out where this function was called, if possible */
if(lua_getstack(lua, 1, &dbg) && lua_getinfo(lua, "nSl", &dbg)) {
sds msg = sdscatprintf(sdsempty(), "%s: %d: %s",
dbg.source, dbg.currentline, error);
lua_pushstring(lua, msg);
sdsfree(msg);
} else {
lua_pushstring(lua, 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) */
}
#define LUA_CMD_OBJCACHE_SIZE 32
#define LUA_CMD_OBJCACHE_MAX_LEN 64
int luaRedisGenericCommand(lua_State *lua, int raise_error) {
int j, argc = lua_gettop(lua);
struct redisCommand *cmd;
redisClient *c = server.lua_client;
sds reply;
/* Cached across calls. */
static robj **argv = NULL;
static int argv_size = 0;
static robj *cached_objects[LUA_CMD_OBJCACHE_SIZE];
static int cached_objects_len[LUA_CMD_OBJCACHE_SIZE];
/* Require at least one argument */
if (argc == 0) {
luaPushError(lua,
"Please specify at least one argument for redis.call()");
return 1;
}
/* Build the arguments vector */
if (!argv) {
argv = zmalloc(sizeof(robj*)*argc);
} else if (argv_size < argc) {
argv = zrealloc(argv,sizeof(robj*)*argc);
argv_size = argc;
}
for (j = 0; j < argc; j++) {
char *obj_s;
size_t obj_len;
char dbuf[64];
if (lua_type(lua,j+1) == LUA_TNUMBER) {
/* We can't use lua_tolstring() for number -> string conversion
* since Lua uses a format specifier that loses precision. */
lua_Number num = lua_tonumber(lua,j+1);
obj_len = snprintf(dbuf,sizeof(dbuf),"%.17g",(double)num);
obj_s = dbuf;
} else {
obj_s = (char*)lua_tolstring(lua,j+1,&obj_len);
if (obj_s == NULL) break; /* Not a string. */
}
/* Try to use a cached object. */
if (j < LUA_CMD_OBJCACHE_SIZE && cached_objects[j] &&
cached_objects_len[j] >= obj_len)
{
char *s = cached_objects[j]->ptr;
struct sdshdr *sh = (void*)(s-(sizeof(struct sdshdr)));
argv[j] = cached_objects[j];
cached_objects[j] = NULL;
memcpy(s,obj_s,obj_len+1);
sh->free += sh->len - obj_len;
sh->len = obj_len;
} else {
argv[j] = createStringObject(obj_s, obj_len);
}
}
/* Check if one of the arguments passed by the Lua script
* is not a string or an integer (lua_isstring() return true for
* integers as well). */
if (j != argc) {
j--;
while (j >= 0) {
decrRefCount(argv[j]);
j--;
}
luaPushError(lua,
"Lua redis() command arguments must be strings or integers");
return 1;
}
/* Setup our fake client for command execution */
c->argv = argv;
c->argc = argc;
/* Command lookup */
cmd = lookupCommand(argv[0]->ptr);
if (!cmd || ((cmd->arity > 0 && cmd->arity != argc) ||
(argc < -cmd->arity)))
{
if (cmd)
luaPushError(lua,
"Wrong number of args calling Redis command From Lua script");
else
luaPushError(lua,"Unknown Redis command called from Lua script");
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;
}
/* 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.loading &&
!(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 */
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
* output buffers. */
if (listLength(c->reply) == 0 && c->bufpos < REDIS_REPLY_CHUNK_BYTES) {
/* This is a fast path for the common case of a reply inside the
* client static buffer. Don't create an SDS string but just use
* the client buffer directly. */
c->buf[c->bufpos] = '\0';
reply = c->buf;
c->bufpos = 0;
} else {
reply = sdsnewlen(c->buf,c->bufpos);
c->bufpos = 0;
while(listLength(c->reply)) {
robj *o = listNodeValue(listFirst(c->reply));
reply = sdscatlen(reply,o->ptr,sdslen(o->ptr));
listDelNode(c->reply,listFirst(c->reply));
}
}
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] != '-')) {
luaSortArray(lua);
}
if (reply != c->buf) sdsfree(reply);
c->reply_bytes = 0;
cleanup:
/* Clean up. Command code may have changed argv/argc so we use the
* argv/argc of the client instead of the local variables. */
for (j = 0; j < c->argc; j++) {
robj *o = c->argv[j];
/* Try to cache the object in the cached_objects array.
* The object must be small, SDS-encoded, and with refcount = 1
* (we must be the only owner) for us to cache it. */
if (j < LUA_CMD_OBJCACHE_SIZE &&
o->refcount == 1 &&
(o->encoding == REDIS_ENCODING_RAW ||
o->encoding == REDIS_ENCODING_EMBSTR) &&
sdslen(o->ptr) <= LUA_CMD_OBJCACHE_MAX_LEN)
{
struct sdshdr *sh = (void*)(((char*)(o->ptr))-(sizeof(struct sdshdr)));
if (cached_objects[j]) decrRefCount(cached_objects[j]);
cached_objects[j] = o;
cached_objects_len[j] = sh->free + sh->len;
} else {
decrRefCount(o);
}
}
if (c->argv != argv) {
zfree(c->argv);
argv = NULL;
}
if (raise_error) {
/* If we are here we should have an error in the stack, in the
* form of a table with an "err" field. Extract the string to
* return the plain error. */
lua_pushstring(lua,"err");
lua_gettable(lua,-2);
return lua_error(lua);
}
return 1;
}
int luaRedisCallCommand(lua_State *lua) {
return luaRedisGenericCommand(lua,1);
}
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;
}
/* Returns a table with a single field 'field' set to the string value
* passed as argument. This helper function is handy when returning
* a Redis Protocol error or status reply from Lua:
*
* return redis.error_reply("ERR Some Error")
* return redis.status_reply("ERR Some Error")
*/
int luaRedisReturnSingleFieldTable(lua_State *lua, char *field) {
if (lua_gettop(lua) != 1 || lua_type(lua,-1) != LUA_TSTRING) {
luaPushError(lua, "wrong number or type of arguments");
return 1;
}
lua_newtable(lua);
lua_pushstring(lua, field);
lua_pushvalue(lua, -3);
lua_settable(lua, -3);
return 1;
}
int luaRedisErrorReplyCommand(lua_State *lua) {
return luaRedisReturnSingleFieldTable(lua,"err");
}
int luaRedisStatusReplyCommand(lua_State *lua) {
return luaRedisReturnSingleFieldTable(lua,"ok");
}
int luaLogCommand(lua_State *lua) {
int j, argc = lua_gettop(lua);
int level;
sds log;
if (argc < 2) {
luaPushError(lua, "redis.log() requires two arguments or more.");
return 1;
} else if (!lua_isnumber(lua,-argc)) {
luaPushError(lua, "First argument must be a number (log level).");
return 1;
}
level = lua_tonumber(lua,-argc);
if (level < REDIS_DEBUG || level > REDIS_WARNING) {
luaPushError(lua, "Invalid debug level.");
return 1;
}
/* Glue together all the arguments */
log = sdsempty();
for (j = 1; j < argc; j++) {
size_t len;
char *s;
s = (char*)lua_tolstring(lua,(-argc)+j,&len);
if (s) {
if (j != 1) log = sdscatlen(log," ",1);
log = sdscatlen(log,s,len);
}
}
redisLogRaw(level,log);
sdsfree(log);
return 0;
}
void luaMaskCountHook(lua_State *lua, lua_Debug *ar) {
long long elapsed;
REDIS_NOTUSED(ar);
REDIS_NOTUSED(lua);
elapsed = mstime() - server.lua_time_start;
if (elapsed >= server.lua_time_limit && server.lua_timedout == 0) {
redisLog(REDIS_WARNING,"Lua slow script detected: still in execution after %lld milliseconds. You can try killing the script using the SCRIPT KILL command.",elapsed);
server.lua_timedout = 1;
/* Once the script timeouts we reenter the event loop to permit others
* to call SCRIPT KILL or SHUTDOWN NOSAVE if needed. For this reason
* we need to mask the client executing the script from the event loop.
* If we don't do that the client may disconnect and could no longer be
* here when the EVAL command will return. */
aeDeleteFileEvent(server.el, server.lua_caller->fd, AE_READABLE);
}
if (server.lua_timedout) processEventsWhileBlocked();
if (server.lua_kill) {
redisLog(REDIS_WARNING,"Lua script killed by user with SCRIPT KILL.");
lua_pushstring(lua,"Script killed by user with SCRIPT KILL...");
lua_error(lua);
}
}
void luaLoadLib(lua_State *lua, const char *libname, lua_CFunction luafunc) {
lua_pushcfunction(lua, luafunc);
lua_pushstring(lua, libname);
lua_call(lua, 1, 0);
}
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);
luaLoadLib(lua, LUA_TABLIBNAME, luaopen_table);
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, "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);
luaLoadLib(lua, LUA_OSLIBNAME, luaopen_os);
#endif
}
/* Remove a functions that we don't want to expose to the Redis scripting
* environment. */
void luaRemoveUnsupportedFunctions(lua_State *lua) {
lua_pushnil(lua);
lua_setglobal(lua,"loadfile");
}
/* 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. */
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.__newindex = function (t, n, v)\n";
s[j++]=" if 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(\"Script attempted to create global variable '\"..tostring(n)..\"'\", 2)\n";
s[j++]=" end\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 debug.getinfo(2, \"S\").what ~= \"C\" then\n";
s[j++]=" error(\"Script attempted to access unexisting global variable '\"..tostring(n)..\"'\", 2)\n";
s[j++]=" end\n";
s[j++]=" return rawget(t, n)\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);
}
/* Initialize the scripting environment.
* It is possible to call this function to reset the scripting environment
* assuming that we call scriptingRelease() before.
* See scriptingReset() for more information. */
void scriptingInit(void) {
lua_State *lua = lua_open();
luaLoadLibraries(lua);
luaRemoveUnsupportedFunctions(lua);
/* Initialize a dictionary we use to map SHAs to scripts.
* This is useful for replication, as we need to replicate EVALSHA
* as EVAL, so we need to remember the associated script. */
server.lua_scripts = dictCreate(&shaScriptObjectDictType,NULL);
/* Register the redis commands table and fields */
lua_newtable(lua);
/* redis.call */
lua_pushstring(lua,"call");
lua_pushcfunction(lua,luaRedisCallCommand);
lua_settable(lua,-3);
/* redis.pcall */
lua_pushstring(lua,"pcall");
lua_pushcfunction(lua,luaRedisPCallCommand);
lua_settable(lua,-3);
/* redis.log and log levels. */
lua_pushstring(lua,"log");
lua_pushcfunction(lua,luaLogCommand);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_DEBUG");
lua_pushnumber(lua,REDIS_DEBUG);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_VERBOSE");
lua_pushnumber(lua,REDIS_VERBOSE);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_NOTICE");
lua_pushnumber(lua,REDIS_NOTICE);
lua_settable(lua,-3);
lua_pushstring(lua,"LOG_WARNING");
lua_pushnumber(lua,REDIS_WARNING);
lua_settable(lua,-3);
/* redis.sha1hex */
lua_pushstring(lua, "sha1hex");
lua_pushcfunction(lua, luaRedisSha1hexCommand);
lua_settable(lua, -3);
/* redis.error_reply and redis.status_reply */
lua_pushstring(lua, "error_reply");
lua_pushcfunction(lua, luaRedisErrorReplyCommand);
lua_settable(lua, -3);
lua_pushstring(lua, "status_reply");
lua_pushcfunction(lua, luaRedisStatusReplyCommand);
lua_settable(lua, -3);
/* Finally set the table as 'redis' global var. */
lua_setglobal(lua,"redis");
/* Replace math.random and math.randomseed with our implementations. */
lua_getglobal(lua,"math");
lua_pushstring(lua,"random");
lua_pushcfunction(lua,redis_math_random);
lua_settable(lua,-3);
lua_pushstring(lua,"randomseed");
lua_pushcfunction(lua,redis_math_randomseed);
lua_settable(lua,-3);
lua_setglobal(lua,"math");
/* Add a helper function 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 a<b\n"
"end\n";
luaL_loadbuffer(lua,compare_func,strlen(compare_func),"@cmp_func_def");
lua_pcall(lua,0,0,0);
}
/* Add a helper function we use for pcall error reporting.
* Note that when the error is in the C function we want to report the
* information about the caller, that's what makes sense from the point
* of view of the user debugging a script. */
{
char *errh_func = "function __redis__err__handler(err)\n"
" local i = debug.getinfo(2,'nSl')\n"
" if i and i.what == 'C' then\n"
" i = debug.getinfo(3,'nSl')\n"
" end\n"
" if i then\n"
" return i.source .. ':' .. i.currentline .. ': ' .. err\n"
" else\n"
" return err\n"
" end\n"
"end\n";
luaL_loadbuffer(lua,errh_func,strlen(errh_func),"@err_handler_def");
lua_pcall(lua,0,0,0);
}
/* Create the (non connected) client that we use to execute Redis commands
* inside the Lua interpreter.
* Note: there is no need to create it again when this function is called
* by scriptingReset(). */
if (server.lua_client == NULL) {
server.lua_client = createClient(-1);
server.lua_client->flags |= 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. */
scriptingEnableGlobalsProtection(lua);
server.lua = lua;
}
/* Release resources related to Lua scripting.
* This function is used in order to reset the scripting environment. */
void scriptingRelease(void) {
dictRelease(server.lua_scripts);
lua_close(server.lua);
}
void scriptingReset(void) {
scriptingRelease();
scriptingInit();
}
/* Perform the SHA1 of the input string. We use this both for hashing 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 sha1hex(char *digest, char *script, size_t len) {
SHA1_CTX ctx;
unsigned char hash[20];
char *cset = "0123456789abcdef";
int j;
SHA1Init(&ctx);
SHA1Update(&ctx,(unsigned char*)script,len);
SHA1Final(hash,&ctx);
for (j = 0; j < 20; j++) {
digest[j*2] = cset[((hash[j]&0xF0)>>4)];
digest[j*2+1] = cset[(hash[j]&0xF)];
}
digest[40] = '\0';
}
void luaReplyToRedisReply(redisClient *c, lua_State *lua) {
int t = lua_type(lua,-1);
switch(t) {
case LUA_TSTRING:
addReplyBulkCBuffer(c,(char*)lua_tostring(lua,-1),lua_strlen(lua,-1));
break;
case LUA_TBOOLEAN:
addReply(c,lua_toboolean(lua,-1) ? shared.cone : shared.nullbulk);
break;
case LUA_TNUMBER:
addReplyLongLong(c,(long long)lua_tonumber(lua,-1));
break;
case LUA_TTABLE:
/* We need to check if it is an array, an error, or a status reply.
* Error are returned as a single element table with 'err' field.
* Status replies are returned as single element table with 'ok' field */
lua_pushstring(lua,"err");
lua_gettable(lua,-2);
t = lua_type(lua,-1);
if (t == LUA_TSTRING) {
sds err = sdsnew(lua_tostring(lua,-1));
sdsmapchars(err,"\r\n"," ",2);
addReplySds(c,sdscatprintf(sdsempty(),"-%s\r\n",err));
sdsfree(err);
lua_pop(lua,2);
return;
}
lua_pop(lua,1);
lua_pushstring(lua,"ok");
lua_gettable(lua,-2);
t = lua_type(lua,-1);
if (t == LUA_TSTRING) {
sds ok = sdsnew(lua_tostring(lua,-1));
sdsmapchars(ok,"\r\n"," ",2);
addReplySds(c,sdscatprintf(sdsempty(),"+%s\r\n",ok));
sdsfree(ok);
lua_pop(lua,1);
} else {
void *replylen = addDeferredMultiBulkLength(c);
int j = 1, mbulklen = 0;
lua_pop(lua,1); /* Discard the 'ok' field value we popped */
while(1) {
lua_pushnumber(lua,j++);
lua_gettable(lua,-2);
t = lua_type(lua,-1);
if (t == LUA_TNIL) {
lua_pop(lua,1);
break;
}
luaReplyToRedisReply(c, lua);
mbulklen++;
}
setDeferredMultiBulkLength(c,replylen,mbulklen);
}
break;
default:
addReply(c,shared.nullbulk);
}
lua_pop(lua,1);
}
/* Set an array of Redis String Objects as a Lua array (table) stored into a
* global variable. */
void luaSetGlobalArray(lua_State *lua, char *var, robj **elev, int elec) {
int j;
lua_newtable(lua);
for (j = 0; j < elec; j++) {
lua_pushlstring(lua,(char*)elev[j]->ptr,sdslen(elev[j]->ptr));
lua_rawseti(lua,-2,j+1);
}
lua_setglobal(lua,var);
}
/* Define a lua function with the specified function name and body.
* The function name musts be a 2 characters long string, since all the
* functions we defined in the Lua context are in the form:
*
* f_<hex sha1 sum>
*
* On success REDIS_OK is returned, and nothing is left on the Lua stack.
* On error REDIS_ERR is returned and an appropriate error is set in the
* client context. */
int luaCreateFunction(redisClient *c, lua_State *lua, char *funcname, robj *body) {
sds funcdef = sdsempty();
funcdef = sdscat(funcdef,"function ");
funcdef = sdscatlen(funcdef,funcname,42);
funcdef = sdscatlen(funcdef,"() ",3);
funcdef = sdscatlen(funcdef,body->ptr,sdslen(body->ptr));
funcdef = sdscatlen(funcdef," end",4);
if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"@user_script")) {
addReplyErrorFormat(c,"Error compiling script (new function): %s\n",
lua_tostring(lua,-1));
lua_pop(lua,1);
sdsfree(funcdef);
return REDIS_ERR;
}
sdsfree(funcdef);
if (lua_pcall(lua,0,0,0)) {
addReplyErrorFormat(c,"Error running script (new function): %s\n",
lua_tostring(lua,-1));
lua_pop(lua,1);
return REDIS_ERR;
}
/* We also save a SHA1 -> Original script map in a dictionary
* so that we can replicate / write in the AOF all the
* EVALSHA commands as EVAL using the original script. */
{
int retval = dictAdd(server.lua_scripts,
sdsnewlen(funcname+2,40),body);
redisAssertWithInfo(c,NULL,retval == DICT_OK);
incrRefCount(body);
}
return REDIS_OK;
}
void evalGenericCommand(redisClient *c, int evalsha) {
lua_State *lua = server.lua;
char funcname[43];
long long numkeys;
int delhook = 0, err;
/* We want the same PRNG sequence at every call so that our PRNG is
* not affected by external state. */
redisSrand48(0);
/* We set this flag to zero to remember that so far no random command
* was called. This way we can allow the user to call commands like
* SRANDMEMBER or RANDOMKEY from Lua scripts as far as no write command
* is called (otherwise the replication and AOF would end with non
* deterministic sequences).
*
* Thanks to this flag we'll raise an error every time a write command
* is called after a random command was used. */
server.lua_random_dirty = 0;
server.lua_write_dirty = 0;
/* Get the number of arguments that are keys */
if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
return;
if (numkeys > (c->argc - 3)) {
addReplyError(c,"Number of keys can't be greater than number of args");
return;
}
/* We obtain the script SHA1, then check if this function is already
* defined into the Lua state */
funcname[0] = 'f';
funcname[1] = '_';
if (!evalsha) {
/* Hash the code if this is an EVAL call */
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;
char *sha = c->argv[1]->ptr;
/* Convert to lowercase. We don't use tolower since the function
* managed to always show up in the profiler output consuming
* a non trivial amount of time. */
for (j = 0; j < 40; j++)
funcname[j+2] = (sha[j] >= 'A' && sha[j] <= 'Z') ?
sha[j]+('a'-'A') : sha[j];
funcname[42] = '\0';
}
/* Push the pcall error handler function on the stack. */
lua_getglobal(lua, "__redis__err__handler");
/* Try to lookup the Lua function */
lua_getglobal(lua, funcname);
if (lua_isnil(lua,-1)) {
lua_pop(lua,1); /* remove the nil from the stack */
/* Function not defined... let's define it if we have the
* body of the function. If this is an EVALSHA call we can just
* return an error. */
if (evalsha) {
lua_pop(lua,1); /* remove the error handler from the stack. */
addReply(c, shared.noscripterr);
return;
}
if (luaCreateFunction(c,lua,funcname,c->argv[1]) == REDIS_ERR) {
lua_pop(lua,1); /* remove the error handler from the stack. */
/* The error is sent to the client by luaCreateFunction()
* itself when it returns REDIS_ERR. */
return;
}
/* Now the following is guaranteed to return non nil */
lua_getglobal(lua, funcname);
redisAssert(!lua_isnil(lua,-1));
}
/* Populate the argv and keys table accordingly to the arguments that
* EVAL received. */
luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);
/* Select the right DB in the context of the Lua client */
selectDb(server.lua_client,c->db->id);
/* Set a hook in order to be able to stop the script execution if it
* is running for too much time.
* We set the hook only if the time limit is enabled as the hook will
* make the Lua script execution slower. */
server.lua_caller = c;
server.lua_time_start = mstime();
server.lua_kill = 0;
if (server.lua_time_limit > 0 && server.masterhost == NULL) {
lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
delhook = 1;
}
/* At this point whether this script was never seen before or if it was
* already defined, we can call it. We have zero arguments and expect
* a single return value. */
err = lua_pcall(lua,0,1,-2);
/* Perform some cleanup that we need to do both on error and success. */
if (delhook) lua_sethook(lua,luaMaskCountHook,0,0); /* Disable hook */
if (server.lua_timedout) {
server.lua_timedout = 0;
/* Restore the readable handler that was unregistered when the
* script timeout was detected. */
aeCreateFileEvent(server.el,c->fd,AE_READABLE,
readQueryFromClient,c);
}
server.lua_caller = NULL;
/* Call the Lua garbage collector from time to time to avoid a
* full cycle performed by Lua, which adds too latency.
*