liblua/lua.c

   1 /*
   2 ** $Id: lua.c,v 1.206 2012/09/29 20:07:06 roberto Exp $
   3 ** Lua stand-alone interpreter
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <signal.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12
  13 #define lua_c
  14
  15 #include "lua.h"
  16
  17 #include "lauxlib.h"
  18 #include "lualib.h"
  19
  20
  21 #if !defined(LUA_PROMPT)
  22 #define LUA_PROMPT              "> "
  23 #define LUA_PROMPT2             ">> "
  24 #endif
  25
  26 #if !defined(LUA_PROGNAME)
  27 #define LUA_PROGNAME            "lua"
  28 #endif
  29
  30 #if !defined(LUA_MAXINPUT)
  31 #define LUA_MAXINPUT            512
  32 #endif
  33
  34 #if !defined(LUA_INIT)
  35 #define LUA_INIT                "LUA_INIT"
  36 #endif
  37
  38 #define LUA_INITVERSION  \
  39         LUA_INIT "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR
  40
  41
  42 /*
  43 ** lua_stdin_is_tty detects whether the standard input is a 'tty' (that
  44 ** is, whether we're running lua interactively).
  45 */
  46 #if defined(LUA_USE_ISATTY)
  47 #include <unistd.h>
  48 #define lua_stdin_is_tty()      isatty(0)
  49 #elif defined(LUA_WIN)
  50 #include <io.h>
  51 #include <stdio.h>
  52 #define lua_stdin_is_tty()      _isatty(_fileno(stdin))
  53 #else
  54 #define lua_stdin_is_tty()      1  /* assume stdin is a tty */
  55 #endif
  56
  57
  58 /*
  59 ** lua_readline defines how to show a prompt and then read a line from
  60 ** the standard input.
  61 ** lua_saveline defines how to "save" a read line in a "history".
  62 ** lua_freeline defines how to free a line read by lua_readline.
  63 */
  64 #if defined(LUA_USE_READLINE)
  65
  66 #include <stdio.h>
  67 #include <readline/readline.h>
  68 #include <readline/history.h>
  69 #define lua_readline(L,b,p)     ((void)L, ((b)=readline(p)) != NULL)
  70 #define lua_saveline(L,idx) \
  71         if (lua_rawlen(L,idx) > 0)  /* non-empty line? */ \
  72           add_history(lua_tostring(L, idx));  /* add it to history */
  73 #define lua_freeline(L,b)       ((void)L, free(b))
  74
  75 #elif !defined(lua_readline)
  76
  77 #define lua_readline(L,b,p) \
  78         ((void)L, fputs(p, stdout), fflush(stdout),  /* show prompt */ \
  79         fgets(b, LUA_MAXINPUT, stdin) != NULL)  /* get line */
  80 #define lua_saveline(L,idx)     { (void)L; (void)idx; }
  81 #define lua_freeline(L,b)       { (void)L; (void)b; }
  82
  83 #endif
  84
  85
  86
  87
  88 static lua_State *globalL = NULL;
  89
  90 static const char *progname = LUA_PROGNAME;
  91
  92
  93
  94 static void lstop (lua_State *L, lua_Debug *ar) {
  95   (void)ar;  /* unused arg. */
  96   lua_sethook(L, NULL, 0, 0);
  97   luaL_error(L, "interrupted!");
  98 }
  99
 100
 101 static void laction (int i) {
 102   signal(i, SIG_DFL); /* if another SIGINT happens before lstop,
 103                               terminate process (default action) */
 104   lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
 105 }
 106
 107
 108 static void print_usage (const char *badoption) {
 109   luai_writestringerror("%s: ", progname);
 110   if (badoption[1] == 'e' || badoption[1] == 'l')
 111     luai_writestringerror("'%s' needs argument\n", badoption);
 112   else
 113     luai_writestringerror("unrecognized option '%s'\n", badoption);
 114   luai_writestringerror(
 115   "usage: %s [options] [script [args]]\n"
 116   "Available options are:\n"
 117   "  -e stat  execute string " LUA_QL("stat") "\n"
 118   "  -i       enter interactive mode after executing " LUA_QL("script") "\n"
 119   "  -l name  require library " LUA_QL("name") "\n"
 120   "  -v       show version information\n"
 121   "  -E       ignore environment variables\n"
 122   "  --       stop handling options\n"
 123   "  -        stop handling options and execute stdin\n"
 124   ,
 125   progname);
 126 }
 127
 128
 129 static void l_message (const char *pname, const char *msg) {
 130   if (pname) luai_writestringerror("%s: ", pname);
 131   luai_writestringerror("%s\n", msg);
 132 }
 133
 134
 135 static int report (lua_State *L, int status) {
 136   if (status != LUA_OK && !lua_isnil(L, -1)) {
 137     const char *msg = lua_tostring(L, -1);
 138     if (msg == NULL) msg = "(error object is not a string)";
 139     l_message(progname, msg);
 140     lua_pop(L, 1);
 141     /* force a complete garbage collection in case of errors */
 142     lua_gc(L, LUA_GCCOLLECT, 0);
 143   }
 144   return status;
 145 }
 146
 147
 148 /* the next function is called unprotected, so it must avoid errors */
 149 static void finalreport (lua_State *L, int status) {
 150   if (status != LUA_OK) {
 151     const char *msg = (lua_type(L, -1) == LUA_TSTRING) ? lua_tostring(L, -1)
 152                                                        : NULL;
 153     if (msg == NULL) msg = "(error object is not a string)";
 154     l_message(progname, msg);
 155     lua_pop(L, 1);
 156   }
 157 }
 158
 159
 160 static int traceback (lua_State *L) {
 161   const char *msg = lua_tostring(L, 1);
 162   if (msg)
 163     luaL_traceback(L, L, msg, 1);
 164   else if (!lua_isnoneornil(L, 1)) {  /* is there an error object? */
 165     if (!luaL_callmeta(L, 1, "__tostring"))  /* try its 'tostring' metamethod */
 166       lua_pushliteral(L, "(no error message)");
 167   }
 168   return 1;
 169 }
 170
 171
 172 static int docall (lua_State *L, int narg, int nres) {
 173   int status;
 174   int base = lua_gettop(L) - narg;  /* function index */
 175   lua_pushcfunction(L, traceback);  /* push traceback function */
 176   lua_insert(L, base);  /* put it under chunk and args */
 177   globalL = L;  /* to be available to 'laction' */
 178   signal(SIGINT, laction);
 179   status = lua_pcall(L, narg, nres, base);
 180   signal(SIGINT, SIG_DFL);
 181   lua_remove(L, base);  /* remove traceback function */
 182   return status;
 183 }
 184
 185
 186 static void print_version (void) {
 187   luai_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT));
 188   luai_writeline();
 189 }
 190
 191
 192 static int getargs (lua_State *L, char **argv, int n) {
 193   int narg;
 194   int i;
 195   int argc = 0;
 196   while (argv[argc]) argc++;  /* count total number of arguments */
 197   narg = argc - (n + 1);  /* number of arguments to the script */
 198   luaL_checkstack(L, narg + 3, "too many arguments to script");
 199   for (i=n+1; i < argc; i++)
 200     lua_pushstring(L, argv[i]);
 201   lua_createtable(L, narg, n + 1);
 202   for (i=0; i < argc; i++) {
 203     lua_pushstring(L, argv[i]);
 204     lua_rawseti(L, -2, i - n);
 205   }
 206   return narg;
 207 }
 208
 209
 210 static int dofile (lua_State *L, const char *name) {
 211   int status = luaL_loadfile(L, name);
 212   if (status == LUA_OK) status = docall(L, 0, 0);
 213   return report(L, status);
 214 }
 215
 216
 217 static int dostring (lua_State *L, const char *s, const char *name) {
 218   int status = luaL_loadbuffer(L, s, strlen(s), name);
 219   if (status == LUA_OK) status = docall(L, 0, 0);
 220   return report(L, status);
 221 }
 222
 223
 224 static int dolibrary (lua_State *L, const char *name) {
 225   int status;
 226   lua_getglobal(L, "require");
 227   lua_pushstring(L, name);
 228   status = docall(L, 1, 1);  /* call 'require(name)' */
 229   if (status == LUA_OK)
 230     lua_setglobal(L, name);  /* global[name] = require return */
 231   return report(L, status);
 232 }
 233
 234
 235 static const char *get_prompt (lua_State *L, int firstline) {
 236   const char *p;
 237   lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2");
 238   p = lua_tostring(L, -1);
 239   if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
 240   return p;
 241 }
 242
 243 /* mark in error messages for incomplete statements */
 244 #define EOFMARK         "<eof>"
 245 #define marklen         (sizeof(EOFMARK)/sizeof(char) - 1)
 246
 247 static int incomplete (lua_State *L, int status) {
 248   if (status == LUA_ERRSYNTAX) {
 249     size_t lmsg;
 250     const char *msg = lua_tolstring(L, -1, &lmsg);
 251     if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) {
 252       lua_pop(L, 1);
 253       return 1;
 254     }
 255   }
 256   return 0;  /* else... */
 257 }
 258
 259
 260 static int pushline (lua_State *L, int firstline) {
 261   char buffer[LUA_MAXINPUT];
 262   char *b = buffer;
 263   size_t l;
 264   const char *prmt = get_prompt(L, firstline);
 265   int readstatus = lua_readline(L, b, prmt);
 266   lua_pop(L, 1);  /* remove result from 'get_prompt' */
 267   if (readstatus == 0)
 268     return 0;  /* no input */
 269   l = strlen(b);
 270   if (l > 0 && b[l-1] == '\n')  /* line ends with newline? */
 271     b[l-1] = '\0';  /* remove it */
 272   if (firstline && b[0] == '=')  /* first line starts with `=' ? */
 273     lua_pushfstring(L, "return %s", b+1);  /* change it to `return' */
 274   else
 275     lua_pushstring(L, b);
 276   lua_freeline(L, b);
 277   return 1;
 278 }
 279
 280
 281 static int loadline (lua_State *L) {
 282   int status;
 283   lua_settop(L, 0);
 284   if (!pushline(L, 1))
 285     return -1;  /* no input */
 286   for (;;) {  /* repeat until gets a complete line */
 287     size_t l;
 288     const char *line = lua_tolstring(L, 1, &l);
 289     status = luaL_loadbuffer(L, line, l, "=stdin");
 290     if (!incomplete(L, status)) break;  /* cannot try to add lines? */
 291     if (!pushline(L, 0))  /* no more input? */
 292       return -1;
 293     lua_pushliteral(L, "\n");  /* add a new line... */
 294     lua_insert(L, -2);  /* ...between the two lines */
 295     lua_concat(L, 3);  /* join them */
 296   }
 297   lua_saveline(L, 1);
 298   lua_remove(L, 1);  /* remove line */
 299   return status;
 300 }
 301
 302
 303 static void dotty (lua_State *L) {
 304   int status;
 305   const char *oldprogname = progname;
 306   progname = NULL;
 307   while ((status = loadline(L)) != -1) {
 308     if (status == LUA_OK) status = docall(L, 0, LUA_MULTRET);
 309     report(L, status);
 310     if (status == LUA_OK && lua_gettop(L) > 0) {  /* any result to print? */
 311       luaL_checkstack(L, LUA_MINSTACK, "too many results to print");
 312       lua_getglobal(L, "print");
 313       lua_insert(L, 1);
 314       if (lua_pcall(L, lua_gettop(L)-1, 0, 0) != LUA_OK)
 315         l_message(progname, lua_pushfstring(L,
 316                                "error calling " LUA_QL("print") " (%s)",
 317                                lua_tostring(L, -1)));
 318     }
 319   }
 320   lua_settop(L, 0);  /* clear stack */
 321   luai_writeline();
 322   progname = oldprogname;
 323 }
 324
 325
 326 static int handle_script (lua_State *L, char **argv, int n) {
 327   int status;
 328   const char *fname;
 329   int narg = getargs(L, argv, n);  /* collect arguments */
 330   lua_setglobal(L, "arg");
 331   fname = argv[n];
 332   if (strcmp(fname, "-") == 0 && strcmp(argv[n-1], "--") != 0)
 333     fname = NULL;  /* stdin */
 334   status = luaL_loadfile(L, fname);
 335   lua_insert(L, -(narg+1));
 336   if (status == LUA_OK)
 337     status = docall(L, narg, LUA_MULTRET);
 338   else
 339     lua_pop(L, narg);
 340   return report(L, status);
 341 }
 342
 343
 344 /* check that argument has no extra characters at the end */
 345 #define noextrachars(x)         {if ((x)[2] != '\0') return -1;}
 346
 347
 348 /* indices of various argument indicators in array args */
 349 #define has_i           0       /* -i */
 350 #define has_v           1       /* -v */
 351 #define has_e           2       /* -e */
 352 #define has_E           3       /* -E */
 353
 354 #define num_has         4       /* number of 'has_*' */
 355
 356
 357 static int collectargs (char **argv, int *args) {
 358   int i;
 359   for (i = 1; argv[i] != NULL; i++) {
 360     if (argv[i][0] != '-')  /* not an option? */
 361         return i;
 362     switch (argv[i][1]) {  /* option */
 363       case '-':
 364         noextrachars(argv[i]);
 365         return (argv[i+1] != NULL ? i+1 : 0);
 366       case '\0':
 367         return i;
 368       case 'E':
 369         args[has_E] = 1;
 370         break;
 371       case 'i':
 372         noextrachars(argv[i]);
 373         args[has_i] = 1;  /* go through */
 374       case 'v':
 375         noextrachars(argv[i]);
 376         args[has_v] = 1;
 377         break;
 378       case 'e':
 379         args[has_e] = 1;  /* go through */
 380       case 'l':  /* both options need an argument */
 381         if (argv[i][2] == '\0') {  /* no concatenated argument? */
 382           i++;  /* try next 'argv' */
 383           if (argv[i] == NULL || argv[i][0] == '-')
 384             return -(i - 1);  /* no next argument or it is another option */
 385         }
 386         break;
 387       default:  /* invalid option; return its index... */
 388         return -i;  /* ...as a negative value */
 389     }
 390   }
 391   return 0;
 392 }
 393
 394
 395 static int runargs (lua_State *L, char **argv, int n) {
 396   int i;
 397   for (i = 1; i < n; i++) {
 398     lua_assert(argv[i][0] == '-');
 399     switch (argv[i][1]) {  /* option */
 400       case 'e': {
 401         const char *chunk = argv[i] + 2;
 402         if (*chunk == '\0') chunk = argv[++i];
 403         lua_assert(chunk != NULL);
 404         if (dostring(L, chunk, "=(command line)") != LUA_OK)
 405           return 0;
 406         break;
 407       }
 408       case 'l': {
 409         const char *filename = argv[i] + 2;
 410         if (*filename == '\0') filename = argv[++i];
 411         lua_assert(filename != NULL);
 412         if (dolibrary(L, filename) != LUA_OK)
 413           return 0;  /* stop if file fails */
 414         break;
 415       }
 416       default: break;
 417     }
 418   }
 419   return 1;
 420 }
 421
 422
 423 static int handle_luainit (lua_State *L) {
 424   const char *name = "=" LUA_INITVERSION;
 425   const char *init = getenv(name + 1);
 426   if (init == NULL) {
 427     name = "=" LUA_INIT;
 428     init = getenv(name + 1);  /* try alternative name */
 429   }
 430   if (init == NULL) return LUA_OK;
 431   else if (init[0] == '@')
 432     return dofile(L, init+1);
 433   else
 434     return dostring(L, init, name);
 435 }
 436
 437
 438 static int pmain (lua_State *L) {
 439   int argc = (int)lua_tointeger(L, 1);
 440   char **argv = (char **)lua_touserdata(L, 2);
 441   int script;
 442   int args[num_has];
 443   args[has_i] = args[has_v] = args[has_e] = args[has_E] = 0;
 444   if (argv[0] && argv[0][0]) progname = argv[0];
 445   script = collectargs(argv, args);
 446   if (script < 0) {  /* invalid arg? */
 447     print_usage(argv[-script]);
 448     return 0;
 449   }
 450   if (args[has_v]) print_version();
 451   if (args[has_E]) {  /* option '-E'? */
 452     lua_pushboolean(L, 1);  /* signal for libraries to ignore env. vars. */
 453     lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
 454   }
 455   /* open standard libraries */
 456   luaL_checkversion(L);
 457   lua_gc(L, LUA_GCSTOP, 0);  /* stop collector during initialization */
 458   luaL_openlibs(L);  /* open libraries */
 459   lua_gc(L, LUA_GCRESTART, 0);
 460   if (!args[has_E] && handle_luainit(L) != LUA_OK)
 461     return 0;  /* error running LUA_INIT */
 462   /* execute arguments -e and -l */
 463   if (!runargs(L, argv, (script > 0) ? script : argc)) return 0;
 464   /* execute main script (if there is one) */
 465   if (script && handle_script(L, argv, script) != LUA_OK) return 0;
 466   if (args[has_i])  /* -i option? */
 467     dotty(L);
 468   else if (script == 0 && !args[has_e] && !args[has_v]) {  /* no arguments? */
 469     if (lua_stdin_is_tty()) {
 470       print_version();
 471       dotty(L);
 472     }
 473     else dofile(L, NULL);  /* executes stdin as a file */
 474   }
 475   lua_pushboolean(L, 1);  /* signal no errors */
 476   return 1;
 477 }
 478
 479
 480 int main (int argc, char **argv) {
 481   int status, result;
 482   lua_State *L = luaL_newstate();  /* create state */
 483   if (L == NULL) {
 484     l_message(argv[0], "cannot create state: not enough memory");
 485     return EXIT_FAILURE;
 486   }
 487   /* call 'pmain' in protected mode */
 488   lua_pushcfunction(L, &pmain);
 489   lua_pushinteger(L, argc);  /* 1st argument */
 490   lua_pushlightuserdata(L, argv); /* 2nd argument */
 491   status = lua_pcall(L, 2, 1, 0);
 492   result = lua_toboolean(L, -1);  /* get result */
 493   finalreport(L, status);
 494   lua_close(L);
 495   return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
 496 }
 497