1 /* 2 ** $Id: lua.c,v 1.230 2017/01/12 17:14:26 roberto Exp $ 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 <signal.h> 13 #include <stdio.h> 14 #include <stdlib.h> 15 #include <string.h> 16 17 #include "lua.h" 18 19 #include "lauxlib.h" 20 #include "lualib.h" 21 22 23 24 #if !defined(LUA_PROMPT) 25 #define LUA_PROMPT "> " 26 #define LUA_PROMPT2 ">> " 27 #endif 28 29 #if !defined(LUA_PROGNAME) 30 #define LUA_PROGNAME "lua" 31 #endif 32 33 #if !defined(LUA_MAXINPUT) 34 #define LUA_MAXINPUT 512 35 #endif 36 37 #if !defined(LUA_INIT_VAR) 38 #define LUA_INIT_VAR "LUA_INIT" 39 #endif 40 41 #define LUA_INITVARVERSION LUA_INIT_VAR LUA_VERSUFFIX 42 43 44 /* 45 ** lua_stdin_is_tty detects whether the standard input is a 'tty' (that 46 ** is, whether we're running lua interactively). 47 */ 48 #if !defined(lua_stdin_is_tty) /* { */ 49 50 #if defined(LUA_USE_POSIX) /* { */ 51 52 #include <unistd.h> 53 #define lua_stdin_is_tty() isatty(0) 54 55 #elif defined(LUA_USE_WINDOWS) /* }{ */ 56 57 #include <io.h> 58 #include <windows.h> 59 60 #define lua_stdin_is_tty() _isatty(_fileno(stdin)) 61 62 #else /* }{ */ 63 64 /* ISO C definition */ 65 #define lua_stdin_is_tty() 1 /* assume stdin is a tty */ 66 67 #endif /* } */ 68 69 #endif /* } */ 70 71 72 /* 73 ** lua_readline defines how to show a prompt and then read a line from 74 ** the standard input. 75 ** lua_saveline defines how to "save" a read line in a "history". 76 ** lua_freeline defines how to free a line read by lua_readline. 77 */ 78 #if !defined(lua_readline) /* { */ 79 80 #if defined(LUA_USE_READLINE) /* { */ 81 82 #include <readline/readline.h> 83 #include <readline/history.h> 84 #define lua_readline(L,b,p) ((void)L, ((b)=readline(p)) != NULL) 85 #define lua_saveline(L,line) ((void)L, add_history(line)) 86 #define lua_freeline(L,b) ((void)L, free(b)) 87 88 #else /* }{ */ 89 90 #define lua_readline(L,b,p) \ 91 ((void)L, fputs(p, stdout), fflush(stdout), /* show prompt */ \ 92 fgets(b, LUA_MAXINPUT, stdin) != NULL) /* get line */ 93 #define lua_saveline(L,line) { (void)L; (void)line; } 94 #define lua_freeline(L,b) { (void)L; (void)b; } 95 96 #endif /* } */ 97 98 #endif /* } */ 99 100 101 102 103 static lua_State *globalL = NULL; 104 105 static const char *progname = LUA_PROGNAME; 106 107 108 /* 109 ** Hook set by signal function to stop the interpreter. 110 */ 111 static void lstop (lua_State *L, lua_Debug *ar) { 112 (void)ar; /* unused arg. */ 113 lua_sethook(L, NULL, 0, 0); /* reset hook */ 114 luaL_error(L, "interrupted!"); 115 } 116 117 118 /* 119 ** Function to be called at a C signal. Because a C signal cannot 120 ** just change a Lua state (as there is no proper synchronization), 121 ** this function only sets a hook that, when called, will stop the 122 ** interpreter. 123 */ 124 static void laction (int i) { 125 signal(i, SIG_DFL); /* if another SIGINT happens, terminate process */ 126 lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1); 127 } 128 129 130 static void print_usage (const char *badoption) { 131 lua_writestringerror("%s: ", progname); 132 if (badoption[1] == 'e' || badoption[1] == 'l') 133 lua_writestringerror("'%s' needs argument\n", badoption); 134 else 135 lua_writestringerror("unrecognized option '%s'\n", badoption); 136 lua_writestringerror( 137 "usage: %s [options] [script [args]]\n" 138 "Available options are:\n" 139 " -e stat execute string 'stat'\n" 140 " -i enter interactive mode after executing 'script'\n" 141 " -l name require library 'name'\n" 142 " -v show version information\n" 143 " -E ignore environment variables\n" 144 " -- stop handling options\n" 145 " - stop handling options and execute stdin\n" 146 , 147 progname); 148 } 149 150 151 /* 152 ** Prints an error message, adding the program name in front of it 153 ** (if present) 154 */ 155 static void l_message (const char *pname, const char *msg) { 156 if (pname) lua_writestringerror("%s: ", pname); 157 lua_writestringerror("%s\n", msg); 158 } 159 160 161 /* 162 ** Check whether 'status' is not OK and, if so, prints the error 163 ** message on the top of the stack. It assumes that the error object 164 ** is a string, as it was either generated by Lua or by 'msghandler'. 165 */ 166 static int report (lua_State *L, int status) { 167 if (status != LUA_OK) { 168 const char *msg = lua_tostring(L, -1); 169 l_message(progname, msg); 170 lua_pop(L, 1); /* remove message */ 171 } 172 return status; 173 } 174 175 176 /* 177 ** Message handler used to run all chunks 178 */ 179 static int msghandler (lua_State *L) { 180 const char *msg = lua_tostring(L, 1); 181 if (msg == NULL) { /* is error object not a string? */ 182 if (luaL_callmeta(L, 1, "__tostring") && /* does it have a metamethod */ 183 lua_type(L, -1) == LUA_TSTRING) /* that produces a string? */ 184 return 1; /* that is the message */ 185 else 186 msg = lua_pushfstring(L, "(error object is a %s value)", 187 luaL_typename(L, 1)); 188 } 189 luaL_traceback(L, L, msg, 1); /* append a standard traceback */ 190 return 1; /* return the traceback */ 191 } 192 193 194 /* 195 ** Interface to 'lua_pcall', which sets appropriate message function 196 ** and C-signal handler. Used to run all chunks. 197 */ 198 static int docall (lua_State *L, int narg, int nres) { 199 int status; 200 int base = lua_gettop(L) - narg; /* function index */ 201 lua_pushcfunction(L, msghandler); /* push message handler */ 202 lua_insert(L, base); /* put it under function and args */ 203 globalL = L; /* to be available to 'laction' */ 204 signal(SIGINT, laction); /* set C-signal handler */ 205 status = lua_pcall(L, narg, nres, base); 206 signal(SIGINT, SIG_DFL); /* reset C-signal handler */ 207 lua_remove(L, base); /* remove message handler from the stack */ 208 return status; 209 } 210 211 212 static void print_version (void) { 213 lua_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT)); 214 lua_writeline(); 215 } 216 217 218 /* 219 ** Create the 'arg' table, which stores all arguments from the 220 ** command line ('argv'). It should be aligned so that, at index 0, 221 ** it has 'argv[script]', which is the script name. The arguments 222 ** to the script (everything after 'script') go to positive indices; 223 ** other arguments (before the script name) go to negative indices. 224 ** If there is no script name, assume interpreter's name as base. 225 */ 226 static void createargtable (lua_State *L, char **argv, int argc, int script) { 227 int i, narg; 228 if (script == argc) script = 0; /* no script name? */ 229 narg = argc - (script + 1); /* number of positive indices */ 230 lua_createtable(L, narg, script + 1); 231 for (i = 0; i < argc; i++) { 232 lua_pushstring(L, argv[i]); 233 lua_rawseti(L, -2, i - script); 234 } 235 lua_setglobal(L, "arg"); 236 } 237 238 239 static int dochunk (lua_State *L, int status) { 240 if (status == LUA_OK) status = docall(L, 0, 0); 241 return report(L, status); 242 } 243 244 245 static int dofile (lua_State *L, const char *name) { 246 return dochunk(L, luaL_loadfile(L, name)); 247 } 248 249 250 static int dostring (lua_State *L, const char *s, const char *name) { 251 return dochunk(L, luaL_loadbuffer(L, s, strlen(s), name)); 252 } 253 254 255 /* 256 ** Calls 'require(name)' and stores the result in a global variable 257 ** with the given name. 258 */ 259 static int dolibrary (lua_State *L, const char *name) { 260 int status; 261 lua_getglobal(L, "require"); 262 lua_pushstring(L, name); 263 status = docall(L, 1, 1); /* call 'require(name)' */ 264 if (status == LUA_OK) 265 lua_setglobal(L, name); /* global[name] = require return */ 266 return report(L, status); 267 } 268 269 270 /* 271 ** Returns the string to be used as a prompt by the interpreter. 272 */ 273 static const char *get_prompt (lua_State *L, int firstline) { 274 const char *p; 275 lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2"); 276 p = lua_tostring(L, -1); 277 if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2); 278 return p; 279 } 280 281 /* mark in error messages for incomplete statements */ 282 #define EOFMARK "<eof>" 283 #define marklen (sizeof(EOFMARK)/sizeof(char) - 1) 284 285 286 /* 287 ** Check whether 'status' signals a syntax error and the error 288 ** message at the top of the stack ends with the above mark for 289 ** incomplete statements. 290 */ 291 static int incomplete (lua_State *L, int status) { 292 if (status == LUA_ERRSYNTAX) { 293 size_t lmsg; 294 const char *msg = lua_tolstring(L, -1, &lmsg); 295 if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) { 296 lua_pop(L, 1); 297 return 1; 298 } 299 } 300 return 0; /* else... */ 301 } 302 303 304 /* 305 ** Prompt the user, read a line, and push it into the Lua stack. 306 */ 307 static int pushline (lua_State *L, int firstline) { 308 char buffer[LUA_MAXINPUT]; 309 char *b = buffer; 310 size_t l; 311 const char *prmt = get_prompt(L, firstline); 312 int readstatus = lua_readline(L, b, prmt); 313 if (readstatus == 0) 314 return 0; /* no input (prompt will be popped by caller) */ 315 lua_pop(L, 1); /* remove prompt */ 316 l = strlen(b); 317 if (l > 0 && b[l-1] == '\n') /* line ends with newline? */ 318 b[--l] = '\0'; /* remove it */ 319 if (firstline && b[0] == '=') /* for compatibility with 5.2, ... */ 320 lua_pushfstring(L, "return %s", b + 1); /* change '=' to 'return' */ 321 else 322 lua_pushlstring(L, b, l); 323 lua_freeline(L, b); 324 return 1; 325 } 326 327 328 /* 329 ** Try to compile line on the stack as 'return <line>;'; on return, stack 330 ** has either compiled chunk or original line (if compilation failed). 331 */ 332 static int addreturn (lua_State *L) { 333 const char *line = lua_tostring(L, -1); /* original line */ 334 const char *retline = lua_pushfstring(L, "return %s;", line); 335 int status = luaL_loadbuffer(L, retline, strlen(retline), "=stdin"); 336 if (status == LUA_OK) { 337 lua_remove(L, -2); /* remove modified line */ 338 if (line[0] != '\0') /* non empty? */ 339 lua_saveline(L, line); /* keep history */ 340 } 341 else 342 lua_pop(L, 2); /* pop result from 'luaL_loadbuffer' and modified line */ 343 return status; 344 } 345 346 347 /* 348 ** Read multiple lines until a complete Lua statement 349 */ 350 static int multiline (lua_State *L) { 351 for (;;) { /* repeat until gets a complete statement */ 352 size_t len; 353 const char *line = lua_tolstring(L, 1, &len); /* get what it has */ 354 int status = luaL_loadbuffer(L, line, len, "=stdin"); /* try it */ 355 if (!incomplete(L, status) || !pushline(L, 0)) { 356 lua_saveline(L, line); /* keep history */ 357 return status; /* cannot or should not try to add continuation line */ 358 } 359 lua_pushliteral(L, "\n"); /* add newline... */ 360 lua_insert(L, -2); /* ...between the two lines */ 361 lua_concat(L, 3); /* join them */ 362 } 363 } 364 365 366 /* 367 ** Read a line and try to load (compile) it first as an expression (by 368 ** adding "return " in front of it) and second as a statement. Return 369 ** the final status of load/call with the resulting function (if any) 370 ** in the top of the stack. 371 */ 372 static int loadline (lua_State *L) { 373 int status; 374 lua_settop(L, 0); 375 if (!pushline(L, 1)) 376 return -1; /* no input */ 377 if ((status = addreturn(L)) != LUA_OK) /* 'return ...' did not work? */ 378 status = multiline(L); /* try as command, maybe with continuation lines */ 379 lua_remove(L, 1); /* remove line from the stack */ 380 lua_assert(lua_gettop(L) == 1); 381 return status; 382 } 383 384 385 /* 386 ** Prints (calling the Lua 'print' function) any values on the stack 387 */ 388 static void l_print (lua_State *L) { 389 int n = lua_gettop(L); 390 if (n > 0) { /* any result to be printed? */ 391 luaL_checkstack(L, LUA_MINSTACK, "too many results to print"); 392 lua_getglobal(L, "print"); 393 lua_insert(L, 1); 394 if (lua_pcall(L, n, 0, 0) != LUA_OK) 395 l_message(progname, lua_pushfstring(L, "error calling 'print' (%s)", 396 lua_tostring(L, -1))); 397 } 398 } 399 400 401 /* 402 ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and 403 ** print any results. 404 */ 405 static void doREPL (lua_State *L) { 406 int status; 407 const char *oldprogname = progname; 408 progname = NULL; /* no 'progname' on errors in interactive mode */ 409 while ((status = loadline(L)) != -1) { 410 if (status == LUA_OK) 411 status = docall(L, 0, LUA_MULTRET); 412 if (status == LUA_OK) l_print(L); 413 else report(L, status); 414 } 415 lua_settop(L, 0); /* clear stack */ 416 lua_writeline(); 417 progname = oldprogname; 418 } 419 420 421 /* 422 ** Push on the stack the contents of table 'arg' from 1 to #arg 423 */ 424 static int pushargs (lua_State *L) { 425 int i, n; 426 if (lua_getglobal(L, "arg") != LUA_TTABLE) 427 luaL_error(L, "'arg' is not a table"); 428 n = (int)luaL_len(L, -1); 429 luaL_checkstack(L, n + 3, "too many arguments to script"); 430 for (i = 1; i <= n; i++) 431 lua_rawgeti(L, -i, i); 432 lua_remove(L, -i); /* remove table from the stack */ 433 return n; 434 } 435 436 437 static int handle_script (lua_State *L, char **argv) { 438 int status; 439 const char *fname = argv[0]; 440 if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0) 441 fname = NULL; /* stdin */ 442 status = luaL_loadfile(L, fname); 443 if (status == LUA_OK) { 444 int n = pushargs(L); /* push arguments to script */ 445 status = docall(L, n, LUA_MULTRET); 446 } 447 return report(L, status); 448 } 449 450 451 452 /* bits of various argument indicators in 'args' */ 453 #define has_error 1 /* bad option */ 454 #define has_i 2 /* -i */ 455 #define has_v 4 /* -v */ 456 #define has_e 8 /* -e */ 457 #define has_E 16 /* -E */ 458 459 /* 460 ** Traverses all arguments from 'argv', returning a mask with those 461 ** needed before running any Lua code (or an error code if it finds 462 ** any invalid argument). 'first' returns the first not-handled argument 463 ** (either the script name or a bad argument in case of error). 464 */ 465 static int collectargs (char **argv, int *first) { 466 int args = 0; 467 int i; 468 for (i = 1; argv[i] != NULL; i++) { 469 *first = i; 470 if (argv[i][0] != '-') /* not an option? */ 471 return args; /* stop handling options */ 472 switch (argv[i][1]) { /* else check option */ 473 case '-': /* '--' */ 474 if (argv[i][2] != '\0') /* extra characters after '--'? */ 475 return has_error; /* invalid option */ 476 *first = i + 1; 477 return args; 478 case '\0': /* '-' */ 479 return args; /* script "name" is '-' */ 480 case 'E': 481 if (argv[i][2] != '\0') /* extra characters after 1st? */ 482 return has_error; /* invalid option */ 483 args |= has_E; 484 break; 485 case 'i': 486 args |= has_i; /* (-i implies -v) *//* FALLTHROUGH */ 487 case 'v': 488 if (argv[i][2] != '\0') /* extra characters after 1st? */ 489 return has_error; /* invalid option */ 490 args |= has_v; 491 break; 492 case 'e': 493 args |= has_e; /* FALLTHROUGH */ 494 case 'l': /* both options need an argument */ 495 if (argv[i][2] == '\0') { /* no concatenated argument? */ 496 i++; /* try next 'argv' */ 497 if (argv[i] == NULL || argv[i][0] == '-') 498 return has_error; /* no next argument or it is another option */ 499 } 500 break; 501 default: /* invalid option */ 502 return has_error; 503 } 504 } 505 *first = i; /* no script name */ 506 return args; 507 } 508 509 510 /* 511 ** Processes options 'e' and 'l', which involve running Lua code. 512 ** Returns 0 if some code raises an error. 513 */ 514 static int runargs (lua_State *L, char **argv, int n) { 515 int i; 516 for (i = 1; i < n; i++) { 517 int option = argv[i][1]; 518 lua_assert(argv[i][0] == '-'); /* already checked */ 519 if (option == 'e' || option == 'l') { 520 int status; 521 const char *extra = argv[i] + 2; /* both options need an argument */ 522 if (*extra == '\0') extra = argv[++i]; 523 lua_assert(extra != NULL); 524 status = (option == 'e') 525 ? dostring(L, extra, "=(command line)") 526 : dolibrary(L, extra); 527 if (status != LUA_OK) return 0; 528 } 529 } 530 return 1; 531 } 532 533 534 535 static int handle_luainit (lua_State *L) { 536 const char *name = "=" LUA_INITVARVERSION; 537 const char *init = getenv(name + 1); 538 if (init == NULL) { 539 name = "=" LUA_INIT_VAR; 540 init = getenv(name + 1); /* try alternative name */ 541 } 542 if (init == NULL) return LUA_OK; 543 else if (init[0] == '@') 544 return dofile(L, init+1); 545 else 546 return dostring(L, init, name); 547 } 548 549 550 /* 551 ** Main body of stand-alone interpreter (to be called in protected mode). 552 ** Reads the options and handles them all. 553 */ 554 static int pmain (lua_State *L) { 555 int argc = (int)lua_tointeger(L, 1); 556 char **argv = (char **)lua_touserdata(L, 2); 557 int script; 558 int args = collectargs(argv, &script); 559 luaL_checkversion(L); /* check that interpreter has correct version */ 560 if (argv[0] && argv[0][0]) progname = argv[0]; 561 if (args == has_error) { /* bad arg? */ 562 print_usage(argv[script]); /* 'script' has index of bad arg. */ 563 return 0; 564 } 565 if (args & has_v) /* option '-v'? */ 566 print_version(); 567 if (args & has_E) { /* option '-E'? */ 568 lua_pushboolean(L, 1); /* signal for libraries to ignore env. vars. */ 569 lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV"); 570 } 571 luaL_openlibs(L); /* open standard libraries */ 572 createargtable(L, argv, argc, script); /* create table 'arg' */ 573 if (!(args & has_E)) { /* no option '-E'? */ 574 if (handle_luainit(L) != LUA_OK) /* run LUA_INIT */ 575 return 0; /* error running LUA_INIT */ 576 } 577 if (!runargs(L, argv, script)) /* execute arguments -e and -l */ 578 return 0; /* something failed */ 579 if (script < argc && /* execute main script (if there is one) */ 580 handle_script(L, argv + script) != LUA_OK) 581 return 0; 582 if (args & has_i) /* -i option? */ 583 doREPL(L); /* do read-eval-print loop */ 584 else if (script == argc && !(args & (has_e | has_v))) { /* no arguments? */ 585 if (lua_stdin_is_tty()) { /* running in interactive mode? */ 586 print_version(); 587 doREPL(L); /* do read-eval-print loop */ 588 } 589 else dofile(L, NULL); /* executes stdin as a file */ 590 } 591 lua_pushboolean(L, 1); /* signal no errors */ 592 return 1; 593 } 594 595 596 int main (int argc, char **argv) { 597 int status, result; 598 lua_State *L = luaL_newstate(); /* create state */ 599 if (L == NULL) { 600 l_message(argv[0], "cannot create state: not enough memory"); 601 return EXIT_FAILURE; 602 } 603 lua_pushcfunction(L, &pmain); /* to call 'pmain' in protected mode */ 604 lua_pushinteger(L, argc); /* 1st argument */ 605 lua_pushlightuserdata(L, argv); /* 2nd argument */ 606 status = lua_pcall(L, 2, 1, 0); /* do the call */ 607 result = lua_toboolean(L, -1); /* get result */ 608 report(L, status); 609 lua_close(L); 610 return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE; 611 } 612 613