external/mit/lua/dist/src/lua.c

   1 /*      $NetBSD: lua.c,v 1.4 2015/10/08 13:21:00 mbalmer Exp $  */
   2
   3 /*
   4 ** Id: lua.c,v 1.225 2015/03/30 15:42:59 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 #if !defined(LUA_PROMPT)
  26 #define LUA_PROMPT              "> "
  27 #define LUA_PROMPT2             ">> "
  28 #endif
  29
  30 #if !defined(LUA_PROGNAME)
  31 #define LUA_PROGNAME            "lua"
  32 #endif
  33
  34 #if !defined(LUA_MAXINPUT)
  35 #define LUA_MAXINPUT            512
  36 #endif
  37
  38 #if !defined(LUA_INIT_VAR)
  39 #define LUA_INIT_VAR            "LUA_INIT"
  40 #endif
  41
  42 #define LUA_INITVARVERSION  \
  43         LUA_INIT_VAR "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR
  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 #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   int status;
 334   size_t len; const char *line;
 335   lua_pushliteral(L, "return ");
 336   lua_pushvalue(L, -2);  /* duplicate line */
 337   lua_concat(L, 2);  /* new line is "return ..." */
 338   line = lua_tolstring(L, -1, &len);
 339   if ((status = luaL_loadbuffer(L, line, len, "=stdin")) == LUA_OK) {
 340     lua_remove(L, -3);  /* remove original line */
 341     line += sizeof("return")/sizeof(char);  /* remove 'return' for history */
 342     if (line[0] != '\0')  /* non empty? */
 343       lua_saveline(L, line);  /* keep history */
 344   }
 345   else
 346     lua_pop(L, 2);  /* remove result from 'luaL_loadbuffer' and new line */
 347   return status;
 348 }
 349
 350
 351 /*
 352 ** Read multiple lines until a complete Lua statement
 353 */
 354 static int multiline (lua_State *L) {
 355   for (;;) {  /* repeat until gets a complete statement */
 356     size_t len;
 357     const char *line = lua_tolstring(L, 1, &len);  /* get what it has */
 358     int status = luaL_loadbuffer(L, line, len, "=stdin");  /* try it */
 359     if (!incomplete(L, status) || !pushline(L, 0)) {
 360       lua_saveline(L, line);  /* keep history */
 361       return status;  /* cannot or should not try to add continuation line */
 362     }
 363     lua_pushliteral(L, "\n");  /* add newline... */
 364     lua_insert(L, -2);  /* ...between the two lines */
 365     lua_concat(L, 3);  /* join them */
 366   }
 367 }
 368
 369
 370 /*
 371 ** Read a line and try to load (compile) it first as an expression (by
 372 ** adding "return " in front of it) and second as a statement. Return
 373 ** the final status of load/call with the resulting function (if any)
 374 ** in the top of the stack.
 375 */
 376 static int loadline (lua_State *L) {
 377   int status;
 378   lua_settop(L, 0);
 379   if (!pushline(L, 1))
 380     return -1;  /* no input */
 381   if ((status = addreturn(L)) != LUA_OK)  /* 'return ...' did not work? */
 382     status = multiline(L);  /* try as command, maybe with continuation lines */
 383   lua_remove(L, 1);  /* remove line from the stack */
 384   lua_assert(lua_gettop(L) == 1);
 385   return status;
 386 }
 387
 388
 389 /*
 390 ** Prints (calling the Lua 'print' function) any values on the stack
 391 */
 392 static void l_print (lua_State *L) {
 393   int n = lua_gettop(L);
 394   if (n > 0) {  /* any result to be printed? */
 395     luaL_checkstack(L, LUA_MINSTACK, "too many results to print");
 396     lua_getglobal(L, "print");
 397     lua_insert(L, 1);
 398     if (lua_pcall(L, n, 0, 0) != LUA_OK)
 399       l_message(progname, lua_pushfstring(L, "error calling 'print' (%s)",
 400                                              lua_tostring(L, -1)));
 401   }
 402 }
 403
 404
 405 /*
 406 ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and
 407 ** print any results.
 408 */
 409 static void doREPL (lua_State *L) {
 410   int status;
 411   const char *oldprogname = progname;
 412   progname = NULL;  /* no 'progname' on errors in interactive mode */
 413   while ((status = loadline(L)) != -1) {
 414     if (status == LUA_OK)
 415       status = docall(L, 0, LUA_MULTRET);
 416     if (status == LUA_OK) l_print(L);
 417     else report(L, status);
 418   }
 419   lua_settop(L, 0);  /* clear stack */
 420   lua_writeline();
 421   progname = oldprogname;
 422 }
 423
 424
 425 /*
 426 ** Push on the stack the contents of table 'arg' from 1 to #arg
 427 */
 428 static int pushargs (lua_State *L) {
 429   int i, n;
 430   if (lua_getglobal(L, "arg") != LUA_TTABLE)
 431     luaL_error(L, "'arg' is not a table");
 432   n = (int)luaL_len(L, -1);
 433   luaL_checkstack(L, n + 3, "too many arguments to script");
 434   for (i = 1; i <= n; i++)
 435     lua_rawgeti(L, -i, i);
 436   lua_remove(L, -i);  /* remove table from the stack */
 437   return n;
 438 }
 439
 440
 441 static int handle_script (lua_State *L, char **argv) {
 442   int status;
 443   const char *fname = argv[0];
 444   if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0)
 445     fname = NULL;  /* stdin */
 446   status = luaL_loadfile(L, fname);
 447   if (status == LUA_OK) {
 448     int n = pushargs(L);  /* push arguments to script */
 449     status = docall(L, n, LUA_MULTRET);
 450   }
 451   return report(L, status);
 452 }
 453
 454
 455
 456 /* bits of various argument indicators in 'args' */
 457 #define has_error       1       /* bad option */
 458 #define has_i           2       /* -i */
 459 #define has_v           4       /* -v */
 460 #define has_e           8       /* -e */
 461 #define has_E           16      /* -E */
 462
 463 /*
 464 ** Traverses all arguments from 'argv', returning a mask with those
 465 ** needed before running any Lua code (or an error code if it finds
 466 ** any invalid argument). 'first' returns the first not-handled argument
 467 ** (either the script name or a bad argument in case of error).
 468 */
 469 static int collectargs (char **argv, int *first) {
 470   int args = 0;
 471   int i;
 472   for (i = 1; argv[i] != NULL; i++) {
 473     *first = i;
 474     if (argv[i][0] != '-')  /* not an option? */
 475         return args;  /* stop handling options */
 476     switch (argv[i][1]) {  /* else check option */
 477       case '-':  /* '--' */
 478         if (argv[i][2] != '\0')  /* extra characters after '--'? */
 479           return has_error;  /* invalid option */
 480         *first = i + 1;
 481         return args;
 482       case '\0':  /* '-' */
 483         return args;  /* script "name" is '-' */
 484       case 'E':
 485         if (argv[i][2] != '\0')  /* extra characters after 1st? */
 486           return has_error;  /* invalid option */
 487         args |= has_E;
 488         break;
 489       case 'i':
 490         args |= has_i;  /* (-i implies -v) *//* FALLTHROUGH */
 491       case 'v':
 492         if (argv[i][2] != '\0')  /* extra characters after 1st? */
 493           return has_error;  /* invalid option */
 494         args |= has_v;
 495         break;
 496       case 'e':
 497         args |= has_e;  /* FALLTHROUGH */
 498       case 'l':  /* both options need an argument */
 499         if (argv[i][2] == '\0') {  /* no concatenated argument? */
 500           i++;  /* try next 'argv' */
 501           if (argv[i] == NULL || argv[i][0] == '-')
 502             return has_error;  /* no next argument or it is another option */
 503         }
 504         break;
 505       default:  /* invalid option */
 506         return has_error;
 507     }
 508   }
 509   *first = i;  /* no script name */
 510   return args;
 511 }
 512
 513
 514 /*
 515 ** Processes options 'e' and 'l', which involve running Lua code.
 516 ** Returns 0 if some code raises an error.
 517 */
 518 static int runargs (lua_State *L, char **argv, int n) {
 519   int i;
 520   for (i = 1; i < n; i++) {
 521     int option = argv[i][1];
 522     lua_assert(argv[i][0] == '-');  /* already checked */
 523     if (option == 'e' || option == 'l') {
 524       int status;
 525       const char *extra = argv[i] + 2;  /* both options need an argument */
 526       if (*extra == '\0') extra = argv[++i];
 527       lua_assert(extra != NULL);
 528       status = (option == 'e')
 529                ? dostring(L, extra, "=(command line)")
 530                : dolibrary(L, extra);
 531       if (status != LUA_OK) return 0;
 532     }
 533   }
 534   return 1;
 535 }
 536
 537
 538 static int handle_luainit (lua_State *L) {
 539   const char *name = "=" LUA_INITVARVERSION;
 540   const char *init = getenv(name + 1);
 541   if (init == NULL) {
 542     name = "=" LUA_INIT_VAR;
 543     init = getenv(name + 1);  /* try alternative name */
 544   }
 545   if (init == NULL) return LUA_OK;
 546   else if (init[0] == '@')
 547     return dofile(L, init+1);
 548   else
 549     return dostring(L, init, name);
 550 }
 551
 552
 553 /*
 554 ** Main body of stand-alone interpreter (to be called in protected mode).
 555 ** Reads the options and handles them all.
 556 */
 557 static int pmain (lua_State *L) {
 558   int argc = (int)lua_tointeger(L, 1);
 559   char **argv = (char **)lua_touserdata(L, 2);
 560   int script;
 561   int args = collectargs(argv, &script);
 562   luaL_checkversion(L);  /* check that interpreter has correct version */
 563   if (argv[0] && argv[0][0]) progname = argv[0];
 564   if (args == has_error) {  /* bad arg? */
 565     print_usage(argv[script]);  /* 'script' has index of bad arg. */
 566     return 0;
 567   }
 568   if (args & has_v)  /* option '-v'? */
 569     print_version();
 570   if (args & has_E) {  /* option '-E'? */
 571     lua_pushboolean(L, 1);  /* signal for libraries to ignore env. vars. */
 572     lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
 573   }
 574   luaL_openlibs(L);  /* open standard libraries */
 575   createargtable(L, argv, argc, script);  /* create table 'arg' */
 576   if (!(args & has_E)) {  /* no option '-E'? */
 577     if (handle_luainit(L) != LUA_OK)  /* run LUA_INIT */
 578       return 0;  /* error running LUA_INIT */
 579   }
 580   if (!runargs(L, argv, script))  /* execute arguments -e and -l */
 581     return 0;  /* something failed */
 582   if (script < argc &&  /* execute main script (if there is one) */
 583       handle_script(L, argv + script) != LUA_OK)
 584     return 0;
 585   if (args & has_i)  /* -i option? */
 586     doREPL(L);  /* do read-eval-print loop */
 587   else if (script == argc && !(args & (has_e | has_v))) {  /* no arguments? */
 588     if (lua_stdin_is_tty()) {  /* running in interactive mode? */
 589       print_version();
 590       doREPL(L);  /* do read-eval-print loop */
 591     }
 592     else dofile(L, NULL);  /* executes stdin as a file */
 593   }
 594   lua_pushboolean(L, 1);  /* signal no errors */
 595   return 1;
 596 }
 597
 598
 599 int main (int argc, char **argv) {
 600   int status, result;
 601   lua_State *L = luaL_newstate();  /* create state */
 602   if (L == NULL) {
 603     l_message(argv[0], "cannot create state: not enough memory");
 604     return EXIT_FAILURE;
 605   }
 606   lua_pushcfunction(L, &pmain);  /* to call 'pmain' in protected mode */
 607   lua_pushinteger(L, argc);  /* 1st argument */
 608   lua_pushlightuserdata(L, argv); /* 2nd argument */
 609   status = lua_pcall(L, 2, 1, 0);  /* do the call */
 610   result = lua_toboolean(L, -1);  /* get result */
 611   report(L, status);
 612   lua_close(L);
 613   return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
 614 }
 615