1 /* 2 ** $Id: lua.c $ 3 ** Lua stand-alone interpreter 4 ** See Copyright Notice in lua.h 5 */ 6 7 #define lua_c 8 9 #include "lprefix.h" 10 11 12 #include <stdio.h> 13 #include <stdlib.h> 14 #include <string.h> 15 16 #include <signal.h> 17 18 #include "lua.h" 19 20 #include "lauxlib.h" 21 #include "lualib.h" 22 23 24 #if !defined(LUA_PROGNAME) 25 #define LUA_PROGNAME "lua" 26 #endif 27 28 #if !defined(LUA_INIT_VAR) 29 #define LUA_INIT_VAR "LUA_INIT" 30 #endif 31 32 #define LUA_INITVARVERSION LUA_INIT_VAR LUA_VERSUFFIX 33 34 35 static lua_State *globalL = NULL; 36 37 static const char *progname = LUA_PROGNAME; 38 39 40 #if defined(LUA_USE_POSIX) /* { */ 41 42 /* 43 ** Use 'sigaction' when available. 44 */ 45 static void setsignal (int sig, void (*handler)(int)) { 46 struct sigaction sa; 47 sa.sa_handler = handler; 48 sa.sa_flags = 0; 49 sigemptyset(&sa.sa_mask); /* do not mask any signal */ 50 sigaction(sig, &sa, NULL); 51 } 52 53 #else /* }{ */ 54 55 #define setsignal signal 56 57 #endif /* } */ 58 59 60 /* 61 ** Hook set by signal function to stop the interpreter. 62 */ 63 static void lstop (lua_State *L, lua_Debug *ar) { 64 (void)ar; /* unused arg. */ 65 lua_sethook(L, NULL, 0, 0); /* reset hook */ 66 luaL_error(L, "interrupted!"); 67 } 68 69 70 /* 71 ** Function to be called at a C signal. Because a C signal cannot 72 ** just change a Lua state (as there is no proper synchronization), 73 ** this function only sets a hook that, when called, will stop the 74 ** interpreter. 75 */ 76 static void laction (int i) { 77 int flag = LUA_MASKCALL | LUA_MASKRET | LUA_MASKLINE | LUA_MASKCOUNT; 78 setsignal(i, SIG_DFL); /* if another SIGINT happens, terminate process */ 79 lua_sethook(globalL, lstop, flag, 1); 80 } 81 82 83 static void print_usage (const char *badoption) { 84 lua_writestringerror("%s: ", progname); 85 if (badoption[1] == 'e' || badoption[1] == 'l') 86 lua_writestringerror("'%s' needs argument\n", badoption); 87 else 88 lua_writestringerror("unrecognized option '%s'\n", badoption); 89 lua_writestringerror( 90 "usage: %s [options] [script [args]]\n" 91 "Available options are:\n" 92 " -e stat execute string 'stat'\n" 93 " -i enter interactive mode after executing 'script'\n" 94 " -l mod require library 'mod' into global 'mod'\n" 95 " -l g=mod require library 'mod' into global 'g'\n" 96 " -v show version information\n" 97 " -E ignore environment variables\n" 98 " -W turn warnings on\n" 99 " -- stop handling options\n" 100 " - stop handling options and execute stdin\n" 101 , 102 progname); 103 } 104 105 106 /* 107 ** Prints an error message, adding the program name in front of it 108 ** (if present) 109 */ 110 static void l_message (const char *pname, const char *msg) { 111 if (pname) lua_writestringerror("%s: ", pname); 112 lua_writestringerror("%s\n", msg); 113 } 114 115 116 /* 117 ** Check whether 'status' is not OK and, if so, prints the error 118 ** message on the top of the stack. 119 */ 120 static int report (lua_State *L, int status) { 121 if (status != LUA_OK) { 122 const char *msg = lua_tostring(L, -1); 123 if (msg == NULL) 124 msg = "(error message not a string)"; 125 l_message(progname, msg); 126 lua_pop(L, 1); /* remove message */ 127 } 128 return status; 129 } 130 131 132 /* 133 ** Message handler used to run all chunks 134 */ 135 static int msghandler (lua_State *L) { 136 const char *msg = lua_tostring(L, 1); 137 if (msg == NULL) { /* is error object not a string? */ 138 if (luaL_callmeta(L, 1, "__tostring") && /* does it have a metamethod */ 139 lua_type(L, -1) == LUA_TSTRING) /* that produces a string? */ 140 return 1; /* that is the message */ 141 else 142 msg = lua_pushfstring(L, "(error object is a %s value)", 143 luaL_typename(L, 1)); 144 } 145 luaL_traceback(L, L, msg, 1); /* append a standard traceback */ 146 return 1; /* return the traceback */ 147 } 148 149 150 /* 151 ** Interface to 'lua_pcall', which sets appropriate message function 152 ** and C-signal handler. Used to run all chunks. 153 */ 154 static int docall (lua_State *L, int narg, int nres) { 155 int status; 156 int base = lua_gettop(L) - narg; /* function index */ 157 lua_pushcfunction(L, msghandler); /* push message handler */ 158 lua_insert(L, base); /* put it under function and args */ 159 globalL = L; /* to be available to 'laction' */ 160 setsignal(SIGINT, laction); /* set C-signal handler */ 161 status = lua_pcall(L, narg, nres, base); 162 setsignal(SIGINT, SIG_DFL); /* reset C-signal handler */ 163 lua_remove(L, base); /* remove message handler from the stack */ 164 return status; 165 } 166 167 168 static void print_version (void) { 169 lua_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT)); 170 lua_writeline(); 171 } 172 173 174 /* 175 ** Create the 'arg' table, which stores all arguments from the 176 ** command line ('argv'). It should be aligned so that, at index 0, 177 ** it has 'argv[script]', which is the script name. The arguments 178 ** to the script (everything after 'script') go to positive indices; 179 ** other arguments (before the script name) go to negative indices. 180 ** If there is no script name, assume interpreter's name as base. 181 ** (If there is no interpreter's name either, 'script' is -1, so 182 ** table sizes are zero.) 183 */ 184 static void createargtable (lua_State *L, char **argv, int argc, int script) { 185 int i, narg; 186 narg = argc - (script + 1); /* number of positive indices */ 187 lua_createtable(L, narg, script + 1); 188 for (i = 0; i < argc; i++) { 189 lua_pushstring(L, argv[i]); 190 lua_rawseti(L, -2, i - script); 191 } 192 lua_setglobal(L, "arg"); 193 } 194 195 196 static int dochunk (lua_State *L, int status) { 197 if (status == LUA_OK) status = docall(L, 0, 0); 198 return report(L, status); 199 } 200 201 202 static int dofile (lua_State *L, const char *name) { 203 return dochunk(L, luaL_loadfile(L, name)); 204 } 205 206 207 static int dostring (lua_State *L, const char *s, const char *name) { 208 return dochunk(L, luaL_loadbuffer(L, s, strlen(s), name)); 209 } 210 211 212 /* 213 ** Receives 'globname[=modname]' and runs 'globname = require(modname)'. 214 ** If there is no explicit modname and globname contains a '-', cut 215 ** the suffix after '-' (the "version") to make the global name. 216 */ 217 static int dolibrary (lua_State *L, char *globname) { 218 int status; 219 char *suffix = NULL; 220 char *modname = strchr(globname, '='); 221 if (modname == NULL) { /* no explicit name? */ 222 modname = globname; /* module name is equal to global name */ 223 suffix = strchr(modname, *LUA_IGMARK); /* look for a suffix mark */ 224 } 225 else { 226 *modname = '\0'; /* global name ends here */ 227 modname++; /* module name starts after the '=' */ 228 } 229 lua_getglobal(L, "require"); 230 lua_pushstring(L, modname); 231 status = docall(L, 1, 1); /* call 'require(modname)' */ 232 if (status == LUA_OK) { 233 if (suffix != NULL) /* is there a suffix mark? */ 234 *suffix = '\0'; /* remove suffix from global name */ 235 lua_setglobal(L, globname); /* globname = require(modname) */ 236 } 237 return report(L, status); 238 } 239 240 241 /* 242 ** Push on the stack the contents of table 'arg' from 1 to #arg 243 */ 244 static int pushargs (lua_State *L) { 245 int i, n; 246 if (lua_getglobal(L, "arg") != LUA_TTABLE) 247 luaL_error(L, "'arg' is not a table"); 248 n = (int)luaL_len(L, -1); 249 luaL_checkstack(L, n + 3, "too many arguments to script"); 250 for (i = 1; i <= n; i++) 251 lua_rawgeti(L, -i, i); 252 lua_remove(L, -i); /* remove table from the stack */ 253 return n; 254 } 255 256 257 static int handle_script (lua_State *L, char **argv) { 258 int status; 259 const char *fname = argv[0]; 260 if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0) 261 fname = NULL; /* stdin */ 262 status = luaL_loadfile(L, fname); 263 if (status == LUA_OK) { 264 int n = pushargs(L); /* push arguments to script */ 265 status = docall(L, n, LUA_MULTRET); 266 } 267 return report(L, status); 268 } 269 270 271 /* bits of various argument indicators in 'args' */ 272 #define has_error 1 /* bad option */ 273 #define has_i 2 /* -i */ 274 #define has_v 4 /* -v */ 275 #define has_e 8 /* -e */ 276 #define has_E 16 /* -E */ 277 278 279 /* 280 ** Traverses all arguments from 'argv', returning a mask with those 281 ** needed before running any Lua code or an error code if it finds any 282 ** invalid argument. In case of error, 'first' is the index of the bad 283 ** argument. Otherwise, 'first' is -1 if there is no program name, 284 ** 0 if there is no script name, or the index of the script name. 285 */ 286 static int collectargs (char **argv, int *first) { 287 int args = 0; 288 int i; 289 if (argv[0] != NULL) { /* is there a program name? */ 290 if (argv[0][0]) /* not empty? */ 291 progname = argv[0]; /* save it */ 292 } 293 else { /* no program name */ 294 *first = -1; 295 return 0; 296 } 297 for (i = 1; argv[i] != NULL; i++) { /* handle arguments */ 298 *first = i; 299 if (argv[i][0] != '-') /* not an option? */ 300 return args; /* stop handling options */ 301 switch (argv[i][1]) { /* else check option */ 302 case '-': /* '--' */ 303 if (argv[i][2] != '\0') /* extra characters after '--'? */ 304 return has_error; /* invalid option */ 305 *first = i + 1; 306 return args; 307 case '\0': /* '-' */ 308 return args; /* script "name" is '-' */ 309 case 'E': 310 if (argv[i][2] != '\0') /* extra characters? */ 311 return has_error; /* invalid option */ 312 args |= has_E; 313 break; 314 case 'W': 315 if (argv[i][2] != '\0') /* extra characters? */ 316 return has_error; /* invalid option */ 317 break; 318 case 'i': 319 args |= has_i; /* (-i implies -v) *//* FALLTHROUGH */ 320 case 'v': 321 if (argv[i][2] != '\0') /* extra characters? */ 322 return has_error; /* invalid option */ 323 args |= has_v; 324 break; 325 case 'e': 326 args |= has_e; /* FALLTHROUGH */ 327 case 'l': /* both options need an argument */ 328 if (argv[i][2] == '\0') { /* no concatenated argument? */ 329 i++; /* try next 'argv' */ 330 if (argv[i] == NULL || argv[i][0] == '-') 331 return has_error; /* no next argument or it is another option */ 332 } 333 break; 334 default: /* invalid option */ 335 return has_error; 336 } 337 } 338 *first = 0; /* no script name */ 339 return args; 340 } 341 342 343 /* 344 ** Processes options 'e' and 'l', which involve running Lua code, and 345 ** 'W', which also affects the state. 346 ** Returns 0 if some code raises an error. 347 */ 348 static int runargs (lua_State *L, char **argv, int n) { 349 int i; 350 for (i = 1; i < n; i++) { 351 int option = argv[i][1]; 352 lua_assert(argv[i][0] == '-'); /* already checked */ 353 switch (option) { 354 case 'e': case 'l': { 355 int status; 356 char *extra = argv[i] + 2; /* both options need an argument */ 357 if (*extra == '\0') extra = argv[++i]; 358 lua_assert(extra != NULL); 359 status = (option == 'e') 360 ? dostring(L, extra, "=(command line)") 361 : dolibrary(L, extra); 362 if (status != LUA_OK) return 0; 363 break; 364 } 365 case 'W': 366 lua_warning(L, "@on", 0); /* warnings on */ 367 break; 368 } 369 } 370 return 1; 371 } 372 373 374 static int handle_luainit (lua_State *L) { 375 const char *name = "=" LUA_INITVARVERSION; 376 const char *init = getenv(name + 1); 377 if (init == NULL) { 378 name = "=" LUA_INIT_VAR; 379 init = getenv(name + 1); /* try alternative name */ 380 } 381 if (init == NULL) return LUA_OK; 382 else if (init[0] == '@') 383 return dofile(L, init+1); 384 else 385 return dostring(L, init, name); 386 } 387 388 389 /* 390 ** {================================================================== 391 ** Read-Eval-Print Loop (REPL) 392 ** =================================================================== 393 */ 394 395 #if !defined(LUA_PROMPT) 396 #define LUA_PROMPT "> " 397 #define LUA_PROMPT2 ">> " 398 #endif 399 400 #if !defined(LUA_MAXINPUT) 401 #define LUA_MAXINPUT 512 402 #endif 403 404 405 /* 406 ** lua_stdin_is_tty detects whether the standard input is a 'tty' (that 407 ** is, whether we're running lua interactively). 408 */ 409 #if !defined(lua_stdin_is_tty) /* { */ 410 411 #if defined(LUA_USE_POSIX) /* { */ 412 413 #include <unistd.h> 414 #define lua_stdin_is_tty() isatty(0) 415 416 #elif defined(LUA_USE_WINDOWS) /* }{ */ 417 418 #include <io.h> 419 #include <windows.h> 420 421 #define lua_stdin_is_tty() _isatty(_fileno(stdin)) 422 423 #else /* }{ */ 424 425 /* ISO C definition */ 426 #define lua_stdin_is_tty() 1 /* assume stdin is a tty */ 427 428 #endif /* } */ 429 430 #endif /* } */ 431 432 433 /* 434 ** lua_readline defines how to show a prompt and then read a line from 435 ** the standard input. 436 ** lua_saveline defines how to "save" a read line in a "history". 437 ** lua_freeline defines how to free a line read by lua_readline. 438 */ 439 #if !defined(lua_readline) /* { */ 440 441 #if defined(LUA_USE_READLINE) /* { */ 442 443 #include <readline/readline.h> 444 #include <readline/history.h> 445 #define lua_initreadline(L) ((void)L, rl_readline_name="lua") 446 #define lua_readline(L,b,p) ((void)L, ((b)=readline(p)) != NULL) 447 #define lua_saveline(L,line) ((void)L, add_history(line)) 448 #define lua_freeline(L,b) ((void)L, free(b)) 449 450 #else /* }{ */ 451 452 #define lua_initreadline(L) ((void)L) 453 #define lua_readline(L,b,p) \ 454 ((void)L, fputs(p, stdout), fflush(stdout), /* show prompt */ \ 455 fgets(b, LUA_MAXINPUT, stdin) != NULL) /* get line */ 456 #define lua_saveline(L,line) { (void)L; (void)line; } 457 #define lua_freeline(L,b) { (void)L; (void)b; } 458 459 #endif /* } */ 460 461 #endif /* } */ 462 463 464 /* 465 ** Return the string to be used as a prompt by the interpreter. Leave 466 ** the string (or nil, if using the default value) on the stack, to keep 467 ** it anchored. 468 */ 469 static const char *get_prompt (lua_State *L, int firstline) { 470 if (lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2") == LUA_TNIL) 471 return (firstline ? LUA_PROMPT : LUA_PROMPT2); /* use the default */ 472 else { /* apply 'tostring' over the value */ 473 const char *p = luaL_tolstring(L, -1, NULL); 474 lua_remove(L, -2); /* remove original value */ 475 return p; 476 } 477 } 478 479 /* mark in error messages for incomplete statements */ 480 #define EOFMARK "<eof>" 481 #define marklen (sizeof(EOFMARK)/sizeof(char) - 1) 482 483 484 /* 485 ** Check whether 'status' signals a syntax error and the error 486 ** message at the top of the stack ends with the above mark for 487 ** incomplete statements. 488 */ 489 static int incomplete (lua_State *L, int status) { 490 if (status == LUA_ERRSYNTAX) { 491 size_t lmsg; 492 const char *msg = lua_tolstring(L, -1, &lmsg); 493 if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) 494 return 1; 495 } 496 return 0; /* else... */ 497 } 498 499 500 /* 501 ** Prompt the user, read a line, and push it into the Lua stack. 502 */ 503 static int pushline (lua_State *L, int firstline) { 504 char buffer[LUA_MAXINPUT]; 505 char *b = buffer; 506 size_t l; 507 const char *prmt = get_prompt(L, firstline); 508 int readstatus = lua_readline(L, b, prmt); 509 lua_pop(L, 1); /* remove prompt */ 510 if (readstatus == 0) 511 return 0; /* no input */ 512 l = strlen(b); 513 if (l > 0 && b[l-1] == '\n') /* line ends with newline? */ 514 b[--l] = '\0'; /* remove it */ 515 if (firstline && b[0] == '=') /* for compatibility with 5.2, ... */ 516 lua_pushfstring(L, "return %s", b + 1); /* change '=' to 'return' */ 517 else 518 lua_pushlstring(L, b, l); 519 lua_freeline(L, b); 520 return 1; 521 } 522 523 524 /* 525 ** Try to compile line on the stack as 'return <line>;'; on return, stack 526 ** has either compiled chunk or original line (if compilation failed). 527 */ 528 static int addreturn (lua_State *L) { 529 const char *line = lua_tostring(L, -1); /* original line */ 530 const char *retline = lua_pushfstring(L, "return %s;", line); 531 int status = luaL_loadbuffer(L, retline, strlen(retline), "=stdin"); 532 if (status == LUA_OK) { 533 lua_remove(L, -2); /* remove modified line */ 534 if (line[0] != '\0') /* non empty? */ 535 lua_saveline(L, line); /* keep history */ 536 } 537 else 538 lua_pop(L, 2); /* pop result from 'luaL_loadbuffer' and modified line */ 539 return status; 540 } 541 542 543 /* 544 ** Read multiple lines until a complete Lua statement 545 */ 546 static int multiline (lua_State *L) { 547 for (;;) { /* repeat until gets a complete statement */ 548 size_t len; 549 const char *line = lua_tolstring(L, 1, &len); /* get what it has */ 550 int status = luaL_loadbuffer(L, line, len, "=stdin"); /* try it */ 551 if (!incomplete(L, status) || !pushline(L, 0)) { 552 lua_saveline(L, line); /* keep history */ 553 return status; /* should not or cannot try to add continuation line */ 554 } 555 lua_remove(L, -2); /* remove error message (from incomplete line) */ 556 lua_pushliteral(L, "\n"); /* add newline... */ 557 lua_insert(L, -2); /* ...between the two lines */ 558 lua_concat(L, 3); /* join them */ 559 } 560 } 561 562 563 /* 564 ** Read a line and try to load (compile) it first as an expression (by 565 ** adding "return " in front of it) and second as a statement. Return 566 ** the final status of load/call with the resulting function (if any) 567 ** in the top of the stack. 568 */ 569 static int loadline (lua_State *L) { 570 int status; 571 lua_settop(L, 0); 572 if (!pushline(L, 1)) 573 return -1; /* no input */ 574 if ((status = addreturn(L)) != LUA_OK) /* 'return ...' did not work? */ 575 status = multiline(L); /* try as command, maybe with continuation lines */ 576 lua_remove(L, 1); /* remove line from the stack */ 577 lua_assert(lua_gettop(L) == 1); 578 return status; 579 } 580 581 582 /* 583 ** Prints (calling the Lua 'print' function) any values on the stack 584 */ 585 static void l_print (lua_State *L) { 586 int n = lua_gettop(L); 587 if (n > 0) { /* any result to be printed? */ 588 luaL_checkstack(L, LUA_MINSTACK, "too many results to print"); 589 lua_getglobal(L, "print"); 590 lua_insert(L, 1); 591 if (lua_pcall(L, n, 0, 0) != LUA_OK) 592 l_message(progname, lua_pushfstring(L, "error calling 'print' (%s)", 593 lua_tostring(L, -1))); 594 } 595 } 596 597 598 /* 599 ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and 600 ** print any results. 601 */ 602 static void doREPL (lua_State *L) { 603 int status; 604 const char *oldprogname = progname; 605 progname = NULL; /* no 'progname' on errors in interactive mode */ 606 lua_initreadline(L); 607 while ((status = loadline(L)) != -1) { 608 if (status == LUA_OK) 609 status = docall(L, 0, LUA_MULTRET); 610 if (status == LUA_OK) l_print(L); 611 else report(L, status); 612 } 613 lua_settop(L, 0); /* clear stack */ 614 lua_writeline(); 615 progname = oldprogname; 616 } 617 618 /* }================================================================== */ 619 620 621 /* 622 ** Main body of stand-alone interpreter (to be called in protected mode). 623 ** Reads the options and handles them all. 624 */ 625 static int pmain (lua_State *L) { 626 int argc = (int)lua_tointeger(L, 1); 627 char **argv = (char **)lua_touserdata(L, 2); 628 int script; 629 int args = collectargs(argv, &script); 630 int optlim = (script > 0) ? script : argc; /* first argv not an option */ 631 luaL_checkversion(L); /* check that interpreter has correct version */ 632 if (args == has_error) { /* bad arg? */ 633 print_usage(argv[script]); /* 'script' has index of bad arg. */ 634 return 0; 635 } 636 if (args & has_v) /* option '-v'? */ 637 print_version(); 638 if (args & has_E) { /* option '-E'? */ 639 lua_pushboolean(L, 1); /* signal for libraries to ignore env. vars. */ 640 lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV"); 641 } 642 luaL_openlibs(L); /* open standard libraries */ 643 createargtable(L, argv, argc, script); /* create table 'arg' */ 644 lua_gc(L, LUA_GCRESTART); /* start GC... */ 645 lua_gc(L, LUA_GCGEN, 0, 0); /* ...in generational mode */ 646 if (!(args & has_E)) { /* no option '-E'? */ 647 if (handle_luainit(L) != LUA_OK) /* run LUA_INIT */ 648 return 0; /* error running LUA_INIT */ 649 } 650 if (!runargs(L, argv, optlim)) /* execute arguments -e and -l */ 651 return 0; /* something failed */ 652 if (script > 0) { /* execute main script (if there is one) */ 653 if (handle_script(L, argv + script) != LUA_OK) 654 return 0; /* interrupt in case of error */ 655 } 656 if (args & has_i) /* -i option? */ 657 doREPL(L); /* do read-eval-print loop */ 658 else if (script < 1 && !(args & (has_e | has_v))) { /* no active option? */ 659 if (lua_stdin_is_tty()) { /* running in interactive mode? */ 660 print_version(); 661 doREPL(L); /* do read-eval-print loop */ 662 } 663 else dofile(L, NULL); /* executes stdin as a file */ 664 } 665 lua_pushboolean(L, 1); /* signal no errors */ 666 return 1; 667 } 668 669 670 int main (int argc, char **argv) { 671 int status, result; 672 lua_State *L = luaL_newstate(); /* create state */ 673 if (L == NULL) { 674 l_message(argv[0], "cannot create state: not enough memory"); 675 return EXIT_FAILURE; 676 } 677 lua_gc(L, LUA_GCSTOP); /* stop GC while building state */ 678 lua_pushcfunction(L, &pmain); /* to call 'pmain' in protected mode */ 679 lua_pushinteger(L, argc); /* 1st argument */ 680 lua_pushlightuserdata(L, argv); /* 2nd argument */ 681 status = lua_pcall(L, 2, 1, 0); /* do the call */ 682 result = lua_toboolean(L, -1); /* get result */ 683 report(L, status); 684 lua_close(L); 685 return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE; 686 } 687 688