src/scripting.c

   1 #include "redis.h"
   2 #include "sha1.h"
   3
   4 #include <lua.h>
   5 #include <lauxlib.h>
   6 #include <lualib.h>
   7
   8 void scriptingInit(void) {
   9     lua_State *lua = lua_open();
  10     luaL_openlibs(lua);
  11     server.lua = lua;
  12 }
  13
  14 /* Hash the scripit into a SHA1 digest. We use this as Lua function name.
  15  * Digest should point to a 41 bytes buffer: 40 for SHA1 converted into an
  16  * hexadecimal number, plus 1 byte for null term. */
  17 void hashScript(char *digest, char *script, size_t len) {
  18     SHA1_CTX ctx;
  19     unsigned char hash[20];
  20     char *cset = "0123456789abcdef";
  21     int j;
  22
  23     SHA1Init(&ctx);
  24     SHA1Update(&ctx,(unsigned char*)script,len);
  25     SHA1Final(hash,&ctx);
  26
  27     for (j = 0; j < 20; j++) {
  28         digest[j*2] = cset[((hash[j]&0xF0)>>4)];
  29         digest[j*2+1] = cset[(hash[j]&0xF)];
  30     }
  31     digest[40] = '\0';
  32 }
  33
  34 void luaReplyToRedisReply(redisClient *c, lua_State *lua) {
  35     int t = lua_type(lua,1);
  36
  37     switch(t) {
  38     case LUA_TSTRING:
  39         addReplyBulkCBuffer(c,(char*)lua_tostring(lua,1),lua_strlen(lua,1));
  40         break;
  41     case LUA_TBOOLEAN:
  42         addReply(c,lua_toboolean(lua,1) ? shared.cone : shared.czero);
  43         break;
  44     case LUA_TNUMBER:
  45         addReplyLongLong(c,(long long)lua_tonumber(lua,1));
  46         break;
  47     default:
  48         addReply(c,shared.nullbulk);
  49     }
  50     lua_pop(lua,1);
  51 }
  52
  53 void evalCommand(redisClient *c) {
  54     lua_State *lua = server.lua;
  55     char funcname[43];
  56
  57     /* We obtain the script SHA1, then check if this function is already
  58      * defined into the Lua state */
  59     funcname[0] = 'f';
  60     funcname[1] = '_';
  61     hashScript(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
  62     lua_getglobal(lua, funcname);
  63     if (lua_isnil(lua,1)) {
  64         /* Function not defined... let's define it. */
  65         sds funcdef = sdsempty();
  66
  67         lua_pop(lua,1); /* remove the nil from the stack */
  68         funcdef = sdscat(funcdef,"function ");
  69         funcdef = sdscatlen(funcdef,funcname,42);
  70         funcdef = sdscatlen(funcdef," ()\n",4);
  71         funcdef = sdscatlen(funcdef,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
  72         funcdef = sdscatlen(funcdef,"\nend\n",5);
  73         printf("Defining:\n%s\n",funcdef);
  74
  75         if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"func definition")) {
  76             addReplyErrorFormat(c,"Error compiling script (new function): %s\n",
  77                 lua_tostring(lua,-1));
  78             lua_pop(lua,1);
  79             return;
  80         }
  81         if (lua_pcall(lua,0,0,0)) {
  82             addReplyErrorFormat(c,"Error running script (new function): %s\n",
  83                 lua_tostring(lua,-1));
  84             lua_pop(lua,1);
  85             return;
  86         }
  87         lua_getglobal(lua, funcname);
  88     }
  89
  90     /* At this point whatever this script was never seen before or if it was
  91      * already defined, we can call it. We have zero arguments and expect
  92      * a single return value. */
  93     if (lua_pcall(lua,0,1,0)) {
  94         addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
  95             funcname, lua_tostring(lua,-1));
  96         lua_pop(lua,1);
  97         return;
  98     }
  99     luaReplyToRedisReply(c,lua);
 100 }