Line data Source code
1 : /*
2 : ** $Id: lua.c,v 1.230.1.1 2017/04/19 17:29:57 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 0 : static void lstop (lua_State *L, lua_Debug *ar) {
112 : (void)ar; /* unused arg. */
113 0 : lua_sethook(L, NULL, 0, 0); /* reset hook */
114 0 : luaL_error(L, "interrupted!");
115 0 : }
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 0 : static void laction (int i) {
125 0 : signal(i, SIG_DFL); /* if another SIGINT happens, terminate process */
126 0 : lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
127 0 : }
128 :
129 :
130 0 : static void print_usage (const char *badoption) {
131 0 : lua_writestringerror("%s: ", progname);
132 0 : if (badoption[1] == 'e' || badoption[1] == 'l')
133 0 : lua_writestringerror("'%s' needs argument\n", badoption);
134 : else
135 0 : lua_writestringerror("unrecognized option '%s'\n", badoption);
136 0 : 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' into global '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 0 : }
149 :
150 :
151 : /*
152 : ** Prints an error message, adding the program name in front of it
153 : ** (if present)
154 : */
155 5 : static void l_message (const char *pname, const char *msg) {
156 5 : if (pname) lua_writestringerror("%s: ", pname);
157 5 : lua_writestringerror("%s\n", msg);
158 5 : }
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 : */
166 290 : static int report (lua_State *L, int status) {
167 290 : if (status != LUA_OK) {
168 5 : const char *msg = lua_tostring(L, -1);
169 5 : l_message(progname, msg);
170 5 : lua_pop(L, 1); /* remove message */
171 : }
172 290 : return status;
173 : }
174 :
175 :
176 : /*
177 : ** Message handler used to run all chunks
178 : */
179 4 : static int msghandler (lua_State *L) {
180 4 : const char *msg = lua_tostring(L, 1);
181 4 : if (msg == NULL) { /* is error object not a string? */
182 3 : if (luaL_callmeta(L, 1, "__tostring") && /* does it have a metamethod */
183 1 : lua_type(L, -1) == LUA_TSTRING) /* that produces a string? */
184 1 : return 1; /* that is the message */
185 : else
186 1 : msg = lua_pushfstring(L, "(error object is a %s value)",
187 : luaL_typename(L, 1));
188 : }
189 3 : luaL_traceback(L, L, msg, 1); /* append a standard traceback */
190 3 : 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 : */
198 222 : static int docall (lua_State *L, int narg, int nres) {
199 : int status;
200 222 : int base = lua_gettop(L) - narg; /* function index */
201 222 : lua_pushcfunction(L, msghandler); /* push message handler */
202 222 : lua_insert(L, base); /* put it under function and args */
203 222 : globalL = L; /* to be available to 'laction' */
204 222 : signal(SIGINT, laction); /* set C-signal handler */
205 222 : status = lua_pcall(L, narg, nres, base);
206 212 : signal(SIGINT, SIG_DFL); /* reset C-signal handler */
207 212 : lua_remove(L, base); /* remove message handler from the stack */
208 212 : return status;
209 : }
210 :
211 :
212 3 : static void print_version (void) {
213 3 : lua_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT));
214 3 : lua_writeline();
215 3 : }
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 86 : static void createargtable (lua_State *L, char **argv, int argc, int script) {
227 : int i, narg;
228 86 : if (script == argc) script = 0; /* no script name? */
229 86 : narg = argc - (script + 1); /* number of positive indices */
230 86 : lua_createtable(L, narg, script + 1);
231 392 : for (i = 0; i < argc; i++) {
232 306 : lua_pushstring(L, argv[i]);
233 306 : lua_rawseti(L, -2, i - script);
234 : }
235 86 : lua_setglobal(L, "arg");
236 86 : }
237 :
238 :
239 113 : static int dochunk (lua_State *L, int status) {
240 113 : if (status == LUA_OK) status = docall(L, 0, 0);
241 108 : return report(L, status);
242 : }
243 :
244 :
245 1 : static int dofile (lua_State *L, const char *name) {
246 1 : return dochunk(L, luaL_loadfile(L, name));
247 : }
248 :
249 :
250 112 : static int dostring (lua_State *L, const char *s, const char *name) {
251 112 : 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 52 : static int dolibrary (lua_State *L, const char *name) {
260 : int status;
261 52 : lua_getglobal(L, "require");
262 52 : lua_pushstring(L, name);
263 52 : status = docall(L, 1, 1); /* call 'require(name)' */
264 52 : if (status == LUA_OK)
265 52 : lua_setglobal(L, name); /* global[name] = require return */
266 52 : return report(L, status);
267 : }
268 :
269 :
270 : /*
271 : ** Returns the string to be used as a prompt by the interpreter.
272 : */
273 0 : static const char *get_prompt (lua_State *L, int firstline) {
274 : const char *p;
275 0 : lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2");
276 0 : p = lua_tostring(L, -1);
277 0 : if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
278 0 : 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 0 : static int incomplete (lua_State *L, int status) {
292 0 : if (status == LUA_ERRSYNTAX) {
293 : size_t lmsg;
294 0 : const char *msg = lua_tolstring(L, -1, &lmsg);
295 0 : if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) {
296 0 : lua_pop(L, 1);
297 0 : return 1;
298 : }
299 : }
300 0 : return 0; /* else... */
301 : }
302 :
303 :
304 : /*
305 : ** Prompt the user, read a line, and push it into the Lua stack.
306 : */
307 0 : static int pushline (lua_State *L, int firstline) {
308 : char buffer[LUA_MAXINPUT];
309 0 : char *b = buffer;
310 : size_t l;
311 0 : const char *prmt = get_prompt(L, firstline);
312 0 : int readstatus = lua_readline(L, b, prmt);
313 0 : if (readstatus == 0)
314 0 : return 0; /* no input (prompt will be popped by caller) */
315 0 : lua_pop(L, 1); /* remove prompt */
316 0 : l = strlen(b);
317 0 : if (l > 0 && b[l-1] == '\n') /* line ends with newline? */
318 0 : b[--l] = '\0'; /* remove it */
319 0 : if (firstline && b[0] == '=') /* for compatibility with 5.2, ... */
320 0 : lua_pushfstring(L, "return %s", b + 1); /* change '=' to 'return' */
321 : else
322 0 : lua_pushlstring(L, b, l);
323 0 : lua_freeline(L, b);
324 0 : 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 0 : static int addreturn (lua_State *L) {
333 0 : const char *line = lua_tostring(L, -1); /* original line */
334 0 : const char *retline = lua_pushfstring(L, "return %s;", line);
335 0 : int status = luaL_loadbuffer(L, retline, strlen(retline), "=stdin");
336 0 : if (status == LUA_OK) {
337 0 : lua_remove(L, -2); /* remove modified line */
338 0 : if (line[0] != '\0') /* non empty? */
339 0 : lua_saveline(L, line); /* keep history */
340 : }
341 : else
342 0 : lua_pop(L, 2); /* pop result from 'luaL_loadbuffer' and modified line */
343 0 : return status;
344 : }
345 :
346 :
347 : /*
348 : ** Read multiple lines until a complete Lua statement
349 : */
350 0 : static int multiline (lua_State *L) {
351 0 : for (;;) { /* repeat until gets a complete statement */
352 : size_t len;
353 0 : const char *line = lua_tolstring(L, 1, &len); /* get what it has */
354 0 : int status = luaL_loadbuffer(L, line, len, "=stdin"); /* try it */
355 0 : if (!incomplete(L, status) || !pushline(L, 0)) {
356 0 : lua_saveline(L, line); /* keep history */
357 0 : return status; /* cannot or should not try to add continuation line */
358 : }
359 0 : lua_pushliteral(L, "\n"); /* add newline... */
360 0 : lua_insert(L, -2); /* ...between the two lines */
361 0 : 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 0 : static int loadline (lua_State *L) {
373 : int status;
374 0 : lua_settop(L, 0);
375 0 : if (!pushline(L, 1))
376 0 : return -1; /* no input */
377 0 : if ((status = addreturn(L)) != LUA_OK) /* 'return ...' did not work? */
378 0 : status = multiline(L); /* try as command, maybe with continuation lines */
379 0 : lua_remove(L, 1); /* remove line from the stack */
380 : lua_assert(lua_gettop(L) == 1);
381 0 : return status;
382 : }
383 :
384 :
385 : /*
386 : ** Prints (calling the Lua 'print' function) any values on the stack
387 : */
388 0 : static void l_print (lua_State *L) {
389 0 : int n = lua_gettop(L);
390 0 : if (n > 0) { /* any result to be printed? */
391 0 : luaL_checkstack(L, LUA_MINSTACK, "too many results to print");
392 0 : lua_getglobal(L, "print");
393 0 : lua_insert(L, 1);
394 0 : if (lua_pcall(L, n, 0, 0) != LUA_OK)
395 0 : l_message(progname, lua_pushfstring(L, "error calling 'print' (%s)",
396 : lua_tostring(L, -1)));
397 : }
398 0 : }
399 :
400 :
401 : /*
402 : ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and
403 : ** print any results.
404 : */
405 0 : static void doREPL (lua_State *L) {
406 : int status;
407 0 : const char *oldprogname = progname;
408 0 : progname = NULL; /* no 'progname' on errors in interactive mode */
409 0 : while ((status = loadline(L)) != -1) {
410 0 : if (status == LUA_OK)
411 0 : status = docall(L, 0, LUA_MULTRET);
412 0 : if (status == LUA_OK) l_print(L);
413 0 : else report(L, status);
414 : }
415 0 : lua_settop(L, 0); /* clear stack */
416 0 : lua_writeline();
417 0 : progname = oldprogname;
418 0 : }
419 :
420 :
421 : /*
422 : ** Push on the stack the contents of table 'arg' from 1 to #arg
423 : */
424 58 : static int pushargs (lua_State *L) {
425 : int i, n;
426 58 : if (lua_getglobal(L, "arg") != LUA_TTABLE)
427 0 : luaL_error(L, "'arg' is not a table");
428 58 : n = (int)luaL_len(L, -1);
429 58 : luaL_checkstack(L, n + 3, "too many arguments to script");
430 58 : for (i = 1; i <= n; i++)
431 0 : lua_rawgeti(L, -i, i);
432 58 : lua_remove(L, -i); /* remove table from the stack */
433 58 : return n;
434 : }
435 :
436 :
437 59 : static int handle_script (lua_State *L, char **argv) {
438 : int status;
439 59 : const char *fname = argv[0];
440 59 : if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0)
441 1 : fname = NULL; /* stdin */
442 59 : status = luaL_loadfile(L, fname);
443 59 : if (status == LUA_OK) {
444 58 : int n = pushargs(L); /* push arguments to script */
445 58 : status = docall(L, n, LUA_MULTRET);
446 : }
447 54 : 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 86 : static int collectargs (char **argv, int *first) {
466 86 : int args = 0;
467 : int i;
468 169 : for (i = 1; argv[i] != NULL; i++) {
469 143 : *first = i;
470 143 : if (argv[i][0] != '-') /* not an option? */
471 57 : return args; /* stop handling options */
472 86 : switch (argv[i][1]) { /* else check option */
473 2 : case '-': /* '--' */
474 2 : if (argv[i][2] != '\0') /* extra characters after '--'? */
475 0 : return has_error; /* invalid option */
476 2 : *first = i + 1;
477 2 : return args;
478 1 : case '\0': /* '-' */
479 1 : return args; /* script "name" is '-' */
480 1 : case 'E':
481 1 : if (argv[i][2] != '\0') /* extra characters after 1st? */
482 0 : return has_error; /* invalid option */
483 1 : args |= has_E;
484 1 : break;
485 0 : case 'i':
486 0 : args |= has_i; /* (-i implies -v) *//* FALLTHROUGH */
487 3 : case 'v':
488 3 : if (argv[i][2] != '\0') /* extra characters after 1st? */
489 0 : return has_error; /* invalid option */
490 3 : args |= has_v;
491 3 : break;
492 27 : case 'e':
493 27 : args |= has_e; /* FALLTHROUGH */
494 79 : case 'l': /* both options need an argument */
495 79 : if (argv[i][2] == '\0') { /* no concatenated argument? */
496 76 : i++; /* try next 'argv' */
497 76 : if (argv[i] == NULL || argv[i][0] == '-')
498 0 : return has_error; /* no next argument or it is another option */
499 : }
500 79 : break;
501 0 : default: /* invalid option */
502 0 : return has_error;
503 : }
504 : }
505 26 : *first = i; /* no script name */
506 26 : 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 86 : static int runargs (lua_State *L, char **argv, int n) {
515 : int i;
516 162 : for (i = 1; i < n; i++) {
517 85 : int option = argv[i][1];
518 : lua_assert(argv[i][0] == '-'); /* already checked */
519 85 : if (option == 'e' || option == 'l') {
520 : int status;
521 79 : const char *extra = argv[i] + 2; /* both options need an argument */
522 79 : if (*extra == '\0') extra = argv[++i];
523 : lua_assert(extra != NULL);
524 74 : status = (option == 'e')
525 27 : ? dostring(L, extra, "=(command line)")
526 79 : : dolibrary(L, extra);
527 74 : if (status != LUA_OK) return 0;
528 : }
529 : }
530 77 : return 1;
531 : }
532 :
533 :
534 :
535 85 : static int handle_luainit (lua_State *L) {
536 85 : const char *name = "=" LUA_INITVARVERSION;
537 85 : const char *init = getenv(name + 1);
538 85 : if (init == NULL) {
539 85 : name = "=" LUA_INIT_VAR;
540 85 : init = getenv(name + 1); /* try alternative name */
541 : }
542 85 : if (init == NULL) return LUA_OK;
543 85 : else if (init[0] == '@')
544 0 : return dofile(L, init+1);
545 : else
546 85 : 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 86 : static int pmain (lua_State *L) {
555 86 : int argc = (int)lua_tointeger(L, 1);
556 86 : char **argv = (char **)lua_touserdata(L, 2);
557 : int script;
558 86 : int args = collectargs(argv, &script);
559 86 : luaL_checkversion(L); /* check that interpreter has correct version */
560 86 : if (argv[0] && argv[0][0]) progname = argv[0];
561 86 : if (args == has_error) { /* bad arg? */
562 0 : print_usage(argv[script]); /* 'script' has index of bad arg. */
563 0 : return 0;
564 : }
565 86 : if (args & has_v) /* option '-v'? */
566 3 : print_version();
567 86 : if (args & has_E) { /* option '-E'? */
568 1 : lua_pushboolean(L, 1); /* signal for libraries to ignore env. vars. */
569 1 : lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
570 : }
571 86 : luaL_openlibs(L); /* open standard libraries */
572 86 : createargtable(L, argv, argc, script); /* create table 'arg' */
573 86 : if (!(args & has_E)) { /* no option '-E'? */
574 85 : if (handle_luainit(L) != LUA_OK) /* run LUA_INIT */
575 0 : return 0; /* error running LUA_INIT */
576 : }
577 86 : if (!runargs(L, argv, script)) /* execute arguments -e and -l */
578 4 : return 0; /* something failed */
579 131 : if (script < argc && /* execute main script (if there is one) */
580 59 : handle_script(L, argv + script) != LUA_OK)
581 1 : return 0;
582 71 : if (args & has_i) /* -i option? */
583 0 : doREPL(L); /* do read-eval-print loop */
584 71 : else if (script == argc && !(args & (has_e | has_v))) { /* no arguments? */
585 1 : if (lua_stdin_is_tty()) { /* running in interactive mode? */
586 0 : print_version();
587 0 : doREPL(L); /* do read-eval-print loop */
588 : }
589 1 : else dofile(L, NULL); /* executes stdin as a file */
590 : }
591 71 : lua_pushboolean(L, 1); /* signal no errors */
592 71 : return 1;
593 : }
594 :
595 :
596 86 : int main (int argc, char **argv) {
597 : int status, result;
598 86 : lua_State *L = luaL_newstate(); /* create state */
599 86 : if (L == NULL) {
600 0 : l_message(argv[0], "cannot create state: not enough memory");
601 0 : return EXIT_FAILURE;
602 : }
603 86 : lua_pushcfunction(L, &pmain); /* to call 'pmain' in protected mode */
604 86 : lua_pushinteger(L, argc); /* 1st argument */
605 86 : lua_pushlightuserdata(L, argv); /* 2nd argument */
606 86 : status = lua_pcall(L, 2, 1, 0); /* do the call */
607 76 : result = lua_toboolean(L, -1); /* get result */
608 76 : report(L, status);
609 76 : lua_close(L);
610 76 : return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
611 : }
612 :
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