1 /* $NetBSD: lua.c,v 1.9 2018/08/04 17:30:01 alnsn Exp $ */ 2 3 /* 4 ** Id: lua.c,v 1.230.1.1 2017/04/19 17:29:57 roberto Exp 5 ** Lua stand-alone interpreter 6 ** See Copyright Notice in lua.h 7 */ 8 9 #define lua_c 10 11 #include "lprefix.h" 12 13 14 #include <signal.h> 15 #include <stdio.h> 16 #include <stdlib.h> 17 #include <string.h> 18 19 #include "lua.h" 20 21 #include "lauxlib.h" 22 #include "lualib.h" 23 24 25 26 #if !defined(LUA_PROMPT) 27 #define LUA_PROMPT "> " 28 #define LUA_PROMPT2 ">> " 29 #endif 30 31 #if !defined(LUA_PROGNAME) 32 #define LUA_PROGNAME "lua" 33 #endif 34 35 #if !defined(LUA_MAXINPUT) 36 #define LUA_MAXINPUT 512 37 #endif 38 39 #if !defined(LUA_INIT_VAR) 40 #define LUA_INIT_VAR "LUA_INIT" 41 #endif 42 43 #define LUA_INITVARVERSION LUA_INIT_VAR LUA_VERSUFFIX 44 45 46 /* 47 ** lua_stdin_is_tty detects whether the standard input is a 'tty' (that 48 ** is, whether we're running lua interactively). 49 */ 50 #if !defined(lua_stdin_is_tty) /* { */ 51 52 #if defined(LUA_USE_POSIX) /* { */ 53 54 #include <unistd.h> 55 #define lua_stdin_is_tty() isatty(0) 56 57 #elif defined(LUA_USE_WINDOWS) /* }{ */ 58 59 #include <io.h> 60 #include <windows.h> 61 62 #define lua_stdin_is_tty() _isatty(_fileno(stdin)) 63 64 #else /* }{ */ 65 66 /* ISO C definition */ 67 #define lua_stdin_is_tty() 1 /* assume stdin is a tty */ 68 69 #endif /* } */ 70 71 #endif /* } */ 72 73 74 /* 75 ** lua_readline defines how to show a prompt and then read a line from 76 ** the standard input. 77 ** lua_saveline defines how to "save" a read line in a "history". 78 ** lua_freeline defines how to free a line read by lua_readline. 79 */ 80 #if !defined(lua_readline) /* { */ 81 82 #if defined(LUA_USE_READLINE) /* { */ 83 84 #include <readline/readline.h> 85 #include <readline/history.h> 86 #define lua_readline(L,b,p) ((void)L, ((b)=readline(p)) != NULL) 87 #define lua_saveline(L,line) ((void)L, add_history(line)) 88 #define lua_freeline(L,b) ((void)L, free(b)) 89 90 #else /* }{ */ 91 92 #define lua_readline(L,b,p) \ 93 ((void)L, fputs(p, stdout), fflush(stdout), /* show prompt */ \ 94 fgets(b, LUA_MAXINPUT, stdin) != NULL) /* get line */ 95 #define lua_saveline(L,line) { (void)L; (void)line; } 96 #define lua_freeline(L,b) { (void)L; (void)b; } 97 98 #endif /* } */ 99 100 #endif /* } */ 101 102 103 104 105 static lua_State *globalL = NULL; 106 107 static const char *progname = LUA_PROGNAME; 108 109 110 /* 111 ** Hook set by signal function to stop the interpreter. 112 */ 113 static void lstop (lua_State *L, lua_Debug *ar) { 114 (void)ar; /* unused arg. */ 115 lua_sethook(L, NULL, 0, 0); /* reset hook */ 116 luaL_error(L, "interrupted!"); 117 } 118 119 120 /* 121 ** Function to be called at a C signal. Because a C signal cannot 122 ** just change a Lua state (as there is no proper synchronization), 123 ** this function only sets a hook that, when called, will stop the 124 ** interpreter. 125 */ 126 static void laction (int i) { 127 signal(i, SIG_DFL); /* if another SIGINT happens, terminate process */ 128 lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1); 129 } 130 131 132 static void print_usage (const char *badoption) { 133 lua_writestringerror("%s: ", progname); 134 if (badoption[1] == 'e' || badoption[1] == 'l') 135 lua_writestringerror("'%s' needs argument\n", badoption); 136 else 137 lua_writestringerror("unrecognized option '%s'\n", badoption); 138 lua_writestringerror( 139 "usage: %s [options] [script [args]]\n" 140 "Available options are:\n" 141 " -e stat execute string 'stat'\n" 142 " -i enter interactive mode after executing 'script'\n" 143 " -l name require library 'name' into global 'name'\n" 144 " -v show version information\n" 145 " -E ignore environment variables\n" 146 " -- stop handling options\n" 147 " - stop handling options and execute stdin\n" 148 , 149 progname); 150 } 151 152 153 /* 154 ** Prints an error message, adding the program name in front of it 155 ** (if present) 156 */ 157 static void l_message (const char *pname, const char *msg) { 158 if (pname) lua_writestringerror("%s: ", pname); 159 lua_writestringerror("%s\n", msg); 160 } 161 162 163 /* 164 ** Check whether 'status' is not OK and, if so, prints the error 165 ** message on the top of the stack. It assumes that the error object 166 ** is a string, as it was either generated by Lua or by 'msghandler'. 167 */ 168 static int report (lua_State *L, int status) { 169 if (status != LUA_OK) { 170 const char *msg = lua_tostring(L, -1); 171 l_message(progname, msg); 172 lua_pop(L, 1); /* remove message */ 173 } 174 return status; 175 } 176 177 178 /* 179 ** Message handler used to run all chunks 180 */ 181 static int msghandler (lua_State *L) { 182 const char *msg = lua_tostring(L, 1); 183 if (msg == NULL) { /* is error object not a string? */ 184 if (luaL_callmeta(L, 1, "__tostring") && /* does it have a metamethod */ 185 lua_type(L, -1) == LUA_TSTRING) /* that produces a string? */ 186 return 1; /* that is the message */ 187 else 188 msg = lua_pushfstring(L, "(error object is a %s value)", 189 luaL_typename(L, 1)); 190 } 191 luaL_traceback(L, L, msg, 1); /* append a standard traceback */ 192 return 1; /* return the traceback */ 193 } 194 195 196 /* 197 ** Interface to 'lua_pcall', which sets appropriate message function 198 ** and C-signal handler. Used to run all chunks. 199 */ 200 static int docall (lua_State *L, int narg, int nres) { 201 int status; 202 int base = lua_gettop(L) - narg; /* function index */ 203 lua_pushcfunction(L, msghandler); /* push message handler */ 204 lua_insert(L, base); /* put it under function and args */ 205 globalL = L; /* to be available to 'laction' */ 206 signal(SIGINT, laction); /* set C-signal handler */ 207 status = lua_pcall(L, narg, nres, base); 208 signal(SIGINT, SIG_DFL); /* reset C-signal handler */ 209 lua_remove(L, base); /* remove message handler from the stack */ 210 return status; 211 } 212 213 214 static void print_version (void) { 215 lua_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT)); 216 lua_writeline(); 217 } 218 219 220 /* 221 ** Create the 'arg' table, which stores all arguments from the 222 ** command line ('argv'). It should be aligned so that, at index 0, 223 ** it has 'argv[script]', which is the script name. The arguments 224 ** to the script (everything after 'script') go to positive indices; 225 ** other arguments (before the script name) go to negative indices. 226 ** If there is no script name, assume interpreter's name as base. 227 */ 228 static void createargtable (lua_State *L, char **argv, int argc, int script) { 229 int i, narg; 230 if (script == argc) script = 0; /* no script name? */ 231 narg = argc - (script + 1); /* number of positive indices */ 232 lua_createtable(L, narg, script + 1); 233 for (i = 0; i < argc; i++) { 234 lua_pushstring(L, argv[i]); 235 lua_rawseti(L, -2, i - script); 236 } 237 lua_setglobal(L, "arg"); 238 } 239 240 241 static int dochunk (lua_State *L, int status) { 242 if (status == LUA_OK) status = docall(L, 0, 0); 243 return report(L, status); 244 } 245 246 247 static int dofile (lua_State *L, const char *name) { 248 return dochunk(L, luaL_loadfile(L, name)); 249 } 250 251 252 static int dostring (lua_State *L, const char *s, const char *name) { 253 return dochunk(L, luaL_loadbuffer(L, s, strlen(s), name)); 254 } 255 256 257 /* 258 ** Calls 'require(name)' and stores the result in a global variable 259 ** with the given name. 260 */ 261 static int dolibrary (lua_State *L, const char *name) { 262 int status; 263 lua_getglobal(L, "require"); 264 lua_pushstring(L, name); 265 status = docall(L, 1, 1); /* call 'require(name)' */ 266 if (status == LUA_OK) 267 lua_setglobal(L, name); /* global[name] = require return */ 268 return report(L, status); 269 } 270 271 272 /* 273 ** Returns the string to be used as a prompt by the interpreter. 274 */ 275 static const char *get_prompt (lua_State *L, int firstline) { 276 const char *p; 277 lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2"); 278 p = lua_tostring(L, -1); 279 if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2); 280 return p; 281 } 282 283 /* mark in error messages for incomplete statements */ 284 #define EOFMARK "<eof>" 285 #define marklen (sizeof(EOFMARK)/sizeof(char) - 1) 286 287 288 /* 289 ** Check whether 'status' signals a syntax error and the error 290 ** message at the top of the stack ends with the above mark for 291 ** incomplete statements. 292 */ 293 static int incomplete (lua_State *L, int status) { 294 if (status == LUA_ERRSYNTAX) { 295 size_t lmsg; 296 const char *msg = lua_tolstring(L, -1, &lmsg); 297 if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) { 298 lua_pop(L, 1); 299 return 1; 300 } 301 } 302 return 0; /* else... */ 303 } 304 305 306 /* 307 ** Prompt the user, read a line, and push it into the Lua stack. 308 */ 309 static int pushline (lua_State *L, int firstline) { 310 char buffer[LUA_MAXINPUT]; 311 char *b = buffer; 312 size_t l; 313 const char *prmt = get_prompt(L, firstline); 314 int readstatus = lua_readline(L, b, prmt); 315 if (readstatus == 0) 316 return 0; /* no input (prompt will be popped by caller) */ 317 lua_pop(L, 1); /* remove prompt */ 318 l = strlen(b); 319 if (l > 0 && b[l-1] == '\n') /* line ends with newline? */ 320 b[--l] = '\0'; /* remove it */ 321 if (firstline && b[0] == '=') /* for compatibility with 5.2, ... */ 322 lua_pushfstring(L, "return %s", b + 1); /* change '=' to 'return' */ 323 else 324 lua_pushlstring(L, b, l); 325 lua_freeline(L, b); 326 return 1; 327 } 328 329 330 /* 331 ** Try to compile line on the stack as 'return <line>;'; on return, stack 332 ** has either compiled chunk or original line (if compilation failed). 333 */ 334 static int addreturn (lua_State *L) { 335 const char *line = lua_tostring(L, -1); /* original line */ 336 const char *retline = lua_pushfstring(L, "return %s;", line); 337 int status = luaL_loadbuffer(L, retline, strlen(retline), "=stdin"); 338 if (status == LUA_OK) { 339 lua_remove(L, -2); /* remove modified line */ 340 if (line[0] != '\0') /* non empty? */ 341 lua_saveline(L, line); /* keep history */ 342 } 343 else 344 lua_pop(L, 2); /* pop result from 'luaL_loadbuffer' and modified line */ 345 return status; 346 } 347 348 349 /* 350 ** Read multiple lines until a complete Lua statement 351 */ 352 static int multiline (lua_State *L) { 353 for (;;) { /* repeat until gets a complete statement */ 354 size_t len; 355 const char *line = lua_tolstring(L, 1, &len); /* get what it has */ 356 int status = luaL_loadbuffer(L, line, len, "=stdin"); /* try it */ 357 if (!incomplete(L, status) || !pushline(L, 0)) { 358 lua_saveline(L, line); /* keep history */ 359 return status; /* cannot or should not try to add continuation line */ 360 } 361 lua_pushliteral(L, "\n"); /* add newline... */ 362 lua_insert(L, -2); /* ...between the two lines */ 363 lua_concat(L, 3); /* join them */ 364 } 365 } 366 367 368 /* 369 ** Read a line and try to load (compile) it first as an expression (by 370 ** adding "return " in front of it) and second as a statement. Return 371 ** the final status of load/call with the resulting function (if any) 372 ** in the top of the stack. 373 */ 374 static int loadline (lua_State *L) { 375 int status; 376 lua_settop(L, 0); 377 if (!pushline(L, 1)) 378 return -1; /* no input */ 379 if ((status = addreturn(L)) != LUA_OK) /* 'return ...' did not work? */ 380 status = multiline(L); /* try as command, maybe with continuation lines */ 381 lua_remove(L, 1); /* remove line from the stack */ 382 lua_assert(lua_gettop(L) == 1); 383 return status; 384 } 385 386 387 /* 388 ** Prints (calling the Lua 'print' function) any values on the stack 389 */ 390 static void l_print (lua_State *L) { 391 int n = lua_gettop(L); 392 if (n > 0) { /* any result to be printed? */ 393 luaL_checkstack(L, LUA_MINSTACK, "too many results to print"); 394 lua_getglobal(L, "print"); 395 lua_insert(L, 1); 396 if (lua_pcall(L, n, 0, 0) != LUA_OK) 397 l_message(progname, lua_pushfstring(L, "error calling 'print' (%s)", 398 lua_tostring(L, -1))); 399 } 400 } 401 402 403 /* 404 ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and 405 ** print any results. 406 */ 407 static void doREPL (lua_State *L) { 408 int status; 409 const char *oldprogname = progname; 410 progname = NULL; /* no 'progname' on errors in interactive mode */ 411 while ((status = loadline(L)) != -1) { 412 if (status == LUA_OK) 413 status = docall(L, 0, LUA_MULTRET); 414 if (status == LUA_OK) l_print(L); 415 else report(L, status); 416 } 417 lua_settop(L, 0); /* clear stack */ 418 lua_writeline(); 419 progname = oldprogname; 420 } 421 422 423 /* 424 ** Push on the stack the contents of table 'arg' from 1 to #arg 425 */ 426 static int pushargs (lua_State *L) { 427 int i, n; 428 if (lua_getglobal(L, "arg") != LUA_TTABLE) 429 luaL_error(L, "'arg' is not a table"); 430 n = (int)luaL_len(L, -1); 431 luaL_checkstack(L, n + 3, "too many arguments to script"); 432 for (i = 1; i <= n; i++) 433 lua_rawgeti(L, -i, i); 434 lua_remove(L, -i); /* remove table from the stack */ 435 return n; 436 } 437 438 439 static int handle_script (lua_State *L, char **argv) { 440 int status; 441 const char *fname = argv[0]; 442 if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0) 443 fname = NULL; /* stdin */ 444 status = luaL_loadfile(L, fname); 445 if (status == LUA_OK) { 446 int n = pushargs(L); /* push arguments to script */ 447 status = docall(L, n, LUA_MULTRET); 448 } 449 return report(L, status); 450 } 451 452 453 454 /* bits of various argument indicators in 'args' */ 455 #define has_error 1 /* bad option */ 456 #define has_i 2 /* -i */ 457 #define has_v 4 /* -v */ 458 #define has_e 8 /* -e */ 459 #define has_E 16 /* -E */ 460 461 /* 462 ** Traverses all arguments from 'argv', returning a mask with those 463 ** needed before running any Lua code (or an error code if it finds 464 ** any invalid argument). 'first' returns the first not-handled argument 465 ** (either the script name or a bad argument in case of error). 466 */ 467 static int collectargs (char **argv, int *first) { 468 int args = 0; 469 int i; 470 for (i = 1; argv[i] != NULL; i++) { 471 *first = i; 472 if (argv[i][0] != '-') /* not an option? */ 473 return args; /* stop handling options */ 474 switch (argv[i][1]) { /* else check option */ 475 case '-': /* '--' */ 476 if (argv[i][2] != '\0') /* extra characters after '--'? */ 477 return has_error; /* invalid option */ 478 *first = i + 1; 479 return args; 480 case '\0': /* '-' */ 481 return args; /* script "name" is '-' */ 482 case 'E': 483 if (argv[i][2] != '\0') /* extra characters after 1st? */ 484 return has_error; /* invalid option */ 485 args |= has_E; 486 break; 487 case 'i': 488 args |= has_i; /* (-i implies -v) *//* FALLTHROUGH */ 489 case 'v': 490 if (argv[i][2] != '\0') /* extra characters after 1st? */ 491 return has_error; /* invalid option */ 492 args |= has_v; 493 break; 494 case 'e': 495 args |= has_e; /* FALLTHROUGH */ 496 case 'l': /* both options need an argument */ 497 if (argv[i][2] == '\0') { /* no concatenated argument? */ 498 i++; /* try next 'argv' */ 499 if (argv[i] == NULL || argv[i][0] == '-') 500 return has_error; /* no next argument or it is another option */ 501 } 502 break; 503 default: /* invalid option */ 504 return has_error; 505 } 506 } 507 *first = i; /* no script name */ 508 return args; 509 } 510 511 512 /* 513 ** Processes options 'e' and 'l', which involve running Lua code. 514 ** Returns 0 if some code raises an error. 515 */ 516 static int runargs (lua_State *L, char **argv, int n) { 517 int i; 518 for (i = 1; i < n; i++) { 519 int option = argv[i][1]; 520 lua_assert(argv[i][0] == '-'); /* already checked */ 521 if (option == 'e' || option == 'l') { 522 int status; 523 const char *extra = argv[i] + 2; /* both options need an argument */ 524 if (*extra == '\0') extra = argv[++i]; 525 lua_assert(extra != NULL); 526 status = (option == 'e') 527 ? dostring(L, extra, "=(command line)") 528 : dolibrary(L, extra); 529 if (status != LUA_OK) return 0; 530 } 531 } 532 return 1; 533 } 534 535 536 537 static int handle_luainit (lua_State *L) { 538 const char *name = "=" LUA_INITVARVERSION; 539 const char *init = getenv(name + 1); 540 if (init == NULL) { 541 name = "=" LUA_INIT_VAR; 542 init = getenv(name + 1); /* try alternative name */ 543 } 544 if (init == NULL) return LUA_OK; 545 else if (init[0] == '@') 546 return dofile(L, init+1); 547 else 548 return dostring(L, init, name); 549 } 550 551 552 /* 553 ** Main body of stand-alone interpreter (to be called in protected mode). 554 ** Reads the options and handles them all. 555 */ 556 static int pmain (lua_State *L) { 557 int argc = (int)lua_tointeger(L, 1); 558 char **argv = (char **)lua_touserdata(L, 2); 559 int script; 560 int args = collectargs(argv, &script); 561 luaL_checkversion(L); /* check that interpreter has correct version */ 562 if (argv[0] && argv[0][0]) progname = argv[0]; 563 if (args == has_error) { /* bad arg? */ 564 print_usage(argv[script]); /* 'script' has index of bad arg. */ 565 return 0; 566 } 567 if (args & has_v) /* option '-v'? */ 568 print_version(); 569 if (args & has_E) { /* option '-E'? */ 570 lua_pushboolean(L, 1); /* signal for libraries to ignore env. vars. */ 571 lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV"); 572 } 573 luaL_openlibs(L); /* open standard libraries */ 574 createargtable(L, argv, argc, script); /* create table 'arg' */ 575 if (!(args & has_E)) { /* no option '-E'? */ 576 if (handle_luainit(L) != LUA_OK) /* run LUA_INIT */ 577 return 0; /* error running LUA_INIT */ 578 } 579 if (!runargs(L, argv, script)) /* execute arguments -e and -l */ 580 return 0; /* something failed */ 581 if (script < argc && /* execute main script (if there is one) */ 582 handle_script(L, argv + script) != LUA_OK) 583 return 0; 584 if (args & has_i) /* -i option? */ 585 doREPL(L); /* do read-eval-print loop */ 586 else if (script == argc && !(args & (has_e | has_v))) { /* no arguments? */ 587 if (lua_stdin_is_tty()) { /* running in interactive mode? */ 588 print_version(); 589 doREPL(L); /* do read-eval-print loop */ 590 } 591 else dofile(L, NULL); /* executes stdin as a file */ 592 } 593 lua_pushboolean(L, 1); /* signal no errors */ 594 return 1; 595 } 596 597 598 int main (int argc, char **argv) { 599 int status, result; 600 lua_State *L = luaL_newstate(); /* create state */ 601 if (L == NULL) { 602 l_message(argv[0], "cannot create state: not enough memory"); 603 return EXIT_FAILURE; 604 } 605 lua_pushcfunction(L, &pmain); /* to call 'pmain' in protected mode */ 606 lua_pushinteger(L, argc); /* 1st argument */ 607 lua_pushlightuserdata(L, argv); /* 2nd argument */ 608 status = lua_pcall(L, 2, 1, 0); /* do the call */ 609 result = lua_toboolean(L, -1); /* get result */ 610 report(L, status); 611 lua_close(L); 612 return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE; 613 } 614 615