ceph/src/lua/src/lua.c

   1 /*
   2 ** $Id: lua.c,v 1.226 2015/08/14 19:11:20 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 #if !defined(LUA_PROMPT)
  24 #define LUA_PROMPT              "> "
  25 #define LUA_PROMPT2             ">> "
  26 #endif
  27
  28 #if !defined(LUA_PROGNAME)
  29 #define LUA_PROGNAME            "lua"
  30 #endif
  31
  32 #if !defined(LUA_MAXINPUT)
  33 #define LUA_MAXINPUT            512
  34 #endif
  35
  36 #if !defined(LUA_INIT_VAR)
  37 #define LUA_INIT_VAR            "LUA_INIT"
  38 #endif
  39
  40 #define LUA_INITVARVERSION  \
  41         LUA_INIT_VAR "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR
  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 #define lua_stdin_is_tty()      _isatty(_fileno(stdin))
  59
  60 #else                           /* }{ */
  61
  62 /* ISO C definition */
  63 #define lua_stdin_is_tty()      1  /* assume stdin is a tty */
  64
  65 #endif                          /* } */
  66
  67 #endif                          /* } */
  68
  69
  70 /*
  71 ** lua_readline defines how to show a prompt and then read a line from
  72 ** the standard input.
  73 ** lua_saveline defines how to "save" a read line in a "history".
  74 ** lua_freeline defines how to free a line read by lua_readline.
  75 */
  76 #if !defined(lua_readline)      /* { */
  77
  78 #if defined(LUA_USE_READLINE)   /* { */
  79
  80 #include <readline/readline.h>
  81 #include <readline/history.h>
  82 #define lua_readline(L,b,p)     ((void)L, ((b)=readline(p)) != NULL)
  83 #define lua_saveline(L,line)    ((void)L, add_history(line))
  84 #define lua_freeline(L,b)       ((void)L, free(b))
  85
  86 #else                           /* }{ */
  87
  88 #define lua_readline(L,b,p) \
  89         ((void)L, fputs(p, stdout), fflush(stdout),  /* show prompt */ \
  90         fgets(b, LUA_MAXINPUT, stdin) != NULL)  /* get line */
  91 #define lua_saveline(L,line)    { (void)L; (void)line; }
  92 #define lua_freeline(L,b)       { (void)L; (void)b; }
  93
  94 #endif                          /* } */
  95
  96 #endif                          /* } */
  97
  98
  99
 100
 101 static lua_State *globalL = NULL;
 102
 103 static const char *progname = LUA_PROGNAME;
 104
 105
 106 /*
 107 ** Hook set by signal function to stop the interpreter.
 108 */
 109 static void lstop (lua_State *L, lua_Debug *ar) {
 110   (void)ar;  /* unused arg. */
 111   lua_sethook(L, NULL, 0, 0);  /* reset hook */
 112   luaL_error(L, "interrupted!");
 113 }
 114
 115
 116 /*
 117 ** Function to be called at a C signal. Because a C signal cannot
 118 ** just change a Lua state (as there is no proper synchronization),
 119 ** this function only sets a hook that, when called, will stop the
 120 ** interpreter.
 121 */
 122 static void laction (int i) {
 123   signal(i, SIG_DFL); /* if another SIGINT happens, terminate process */
 124   lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
 125 }
 126
 127
 128 static void print_usage (const char *badoption) {
 129   lua_writestringerror("%s: ", progname);
 130   if (badoption[1] == 'e' || badoption[1] == 'l')
 131     lua_writestringerror("'%s' needs argument\n", badoption);
 132   else
 133     lua_writestringerror("unrecognized option '%s'\n", badoption);
 134   lua_writestringerror(
 135   "usage: %s [options] [script [args]]\n"
 136   "Available options are:\n"
 137   "  -e stat  execute string 'stat'\n"
 138   "  -i       enter interactive mode after executing 'script'\n"
 139   "  -l name  require library 'name'\n"
 140   "  -v       show version information\n"
 141   "  -E       ignore environment variables\n"
 142   "  --       stop handling options\n"
 143   "  -        stop handling options and execute stdin\n"
 144   ,
 145   progname);
 146 }
 147
 148
 149 /*
 150 ** Prints an error message, adding the program name in front of it
 151 ** (if present)
 152 */
 153 static void l_message (const char *pname, const char *msg) {
 154   if (pname) lua_writestringerror("%s: ", pname);
 155   lua_writestringerror("%s\n", msg);
 156 }
 157
 158
 159 /*
 160 ** Check whether 'status' is not OK and, if so, prints the error
 161 ** message on the top of the stack. It assumes that the error object
 162 ** is a string, as it was either generated by Lua or by 'msghandler'.
 163 */
 164 static int report (lua_State *L, int status) {
 165   if (status != LUA_OK) {
 166     const char *msg = lua_tostring(L, -1);
 167     l_message(progname, msg);
 168     lua_pop(L, 1);  /* remove message */
 169   }
 170   return status;
 171 }
 172
 173
 174 /*
 175 ** Message handler used to run all chunks
 176 */
 177 static int msghandler (lua_State *L) {
 178   const char *msg = lua_tostring(L, 1);
 179   if (msg == NULL) {  /* is error object not a string? */
 180     if (luaL_callmeta(L, 1, "__tostring") &&  /* does it have a metamethod */
 181         lua_type(L, -1) == LUA_TSTRING)  /* that produces a string? */
 182       return 1;  /* that is the message */
 183     else
 184       msg = lua_pushfstring(L, "(error object is a %s value)",
 185                                luaL_typename(L, 1));
 186   }
 187   luaL_traceback(L, L, msg, 1);  /* append a standard traceback */
 188   return 1;  /* return the traceback */
 189 }
 190
 191
 192 /*
 193 ** Interface to 'lua_pcall', which sets appropriate message function
 194 ** and C-signal handler. Used to run all chunks.
 195 */
 196 static int docall (lua_State *L, int narg, int nres) {
 197   int status;
 198   int base = lua_gettop(L) - narg;  /* function index */
 199   lua_pushcfunction(L, msghandler);  /* push message handler */
 200   lua_insert(L, base);  /* put it under function and args */
 201   globalL = L;  /* to be available to 'laction' */
 202   signal(SIGINT, laction);  /* set C-signal handler */
 203   status = lua_pcall(L, narg, nres, base);
 204   signal(SIGINT, SIG_DFL); /* reset C-signal handler */
 205   lua_remove(L, base);  /* remove message handler from the stack */
 206   return status;
 207 }
 208
 209
 210 static void print_version (void) {
 211   lua_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT));
 212   lua_writeline();
 213 }
 214
 215
 216 /*
 217 ** Create the 'arg' table, which stores all arguments from the
 218 ** command line ('argv'). It should be aligned so that, at index 0,
 219 ** it has 'argv[script]', which is the script name. The arguments
 220 ** to the script (everything after 'script') go to positive indices;
 221 ** other arguments (before the script name) go to negative indices.
 222 ** If there is no script name, assume interpreter's name as base.
 223 */
 224 static void createargtable (lua_State *L, char **argv, int argc, int script) {
 225   int i, narg;
 226   if (script == argc) script = 0;  /* no script name? */
 227   narg = argc - (script + 1);  /* number of positive indices */
 228   lua_createtable(L, narg, script + 1);
 229   for (i = 0; i < argc; i++) {
 230     lua_pushstring(L, argv[i]);
 231     lua_rawseti(L, -2, i - script);
 232   }
 233   lua_setglobal(L, "arg");
 234 }
 235
 236
 237 static int dochunk (lua_State *L, int status) {
 238   if (status == LUA_OK) status = docall(L, 0, 0);
 239   return report(L, status);
 240 }
 241
 242
 243 static int dofile (lua_State *L, const char *name) {
 244   return dochunk(L, luaL_loadfile(L, name));
 245 }
 246
 247
 248 static int dostring (lua_State *L, const char *s, const char *name) {
 249   return dochunk(L, luaL_loadbuffer(L, s, strlen(s), name));
 250 }
 251
 252
 253 /*
 254 ** Calls 'require(name)' and stores the result in a global variable
 255 ** with the given name.
 256 */
 257 static int dolibrary (lua_State *L, const char *name) {
 258   int status;
 259   lua_getglobal(L, "require");
 260   lua_pushstring(L, name);
 261   status = docall(L, 1, 1);  /* call 'require(name)' */
 262   if (status == LUA_OK)
 263     lua_setglobal(L, name);  /* global[name] = require return */
 264   return report(L, status);
 265 }
 266
 267
 268 /*
 269 ** Returns the string to be used as a prompt by the interpreter.
 270 */
 271 static const char *get_prompt (lua_State *L, int firstline) {
 272   const char *p;
 273   lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2");
 274   p = lua_tostring(L, -1);
 275   if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
 276   return p;
 277 }
 278
 279 /* mark in error messages for incomplete statements */
 280 #define EOFMARK         "<eof>"
 281 #define marklen         (sizeof(EOFMARK)/sizeof(char) - 1)
 282
 283
 284 /*
 285 ** Check whether 'status' signals a syntax error and the error
 286 ** message at the top of the stack ends with the above mark for
 287 ** incomplete statements.
 288 */
 289 static int incomplete (lua_State *L, int status) {
 290   if (status == LUA_ERRSYNTAX) {
 291     size_t lmsg;
 292     const char *msg = lua_tolstring(L, -1, &lmsg);
 293     if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) {
 294       lua_pop(L, 1);
 295       return 1;
 296     }
 297   }
 298   return 0;  /* else... */
 299 }
 300
 301
 302 /*
 303 ** Prompt the user, read a line, and push it into the Lua stack.
 304 */
 305 static int pushline (lua_State *L, int firstline) {
 306   char buffer[LUA_MAXINPUT];
 307   char *b = buffer;
 308   size_t l;
 309   const char *prmt = get_prompt(L, firstline);
 310   int readstatus = lua_readline(L, b, prmt);
 311   if (readstatus == 0)
 312     return 0;  /* no input (prompt will be popped by caller) */
 313   lua_pop(L, 1);  /* remove prompt */
 314   l = strlen(b);
 315   if (l > 0 && b[l-1] == '\n')  /* line ends with newline? */
 316     b[--l] = '\0';  /* remove it */
 317   if (firstline && b[0] == '=')  /* for compatibility with 5.2, ... */
 318     lua_pushfstring(L, "return %s", b + 1);  /* change '=' to 'return' */
 319   else
 320     lua_pushlstring(L, b, l);
 321   lua_freeline(L, b);
 322   return 1;
 323 }
 324
 325
 326 /*
 327 ** Try to compile line on the stack as 'return <line>;'; on return, stack
 328 ** has either compiled chunk or original line (if compilation failed).
 329 */
 330 static int addreturn (lua_State *L) {
 331   const char *line = lua_tostring(L, -1);  /* original line */
 332   const char *retline = lua_pushfstring(L, "return %s;", line);
 333   int status = luaL_loadbuffer(L, retline, strlen(retline), "=stdin");
 334   if (status == LUA_OK) {
 335     lua_remove(L, -2);  /* remove modified line */
 336     if (line[0] != '\0')  /* non empty? */
 337       lua_saveline(L, line);  /* keep history */
 338   }
 339   else
 340     lua_pop(L, 2);  /* pop result from 'luaL_loadbuffer' and modified line */
 341   return status;
 342 }
 343
 344
 345 /*
 346 ** Read multiple lines until a complete Lua statement
 347 */
 348 static int multiline (lua_State *L) {
 349   for (;;) {  /* repeat until gets a complete statement */
 350     size_t len;
 351     const char *line = lua_tolstring(L, 1, &len);  /* get what it has */
 352     int status = luaL_loadbuffer(L, line, len, "=stdin");  /* try it */
 353     if (!incomplete(L, status) || !pushline(L, 0)) {
 354       lua_saveline(L, line);  /* keep history */
 355       return status;  /* cannot or should not try to add continuation line */
 356     }
 357     lua_pushliteral(L, "\n");  /* add newline... */
 358     lua_insert(L, -2);  /* ...between the two lines */
 359     lua_concat(L, 3);  /* join them */
 360   }
 361 }
 362
 363
 364 /*
 365 ** Read a line and try to load (compile) it first as an expression (by
 366 ** adding "return " in front of it) and second as a statement. Return
 367 ** the final status of load/call with the resulting function (if any)
 368 ** in the top of the stack.
 369 */
 370 static int loadline (lua_State *L) {
 371   int status;
 372   lua_settop(L, 0);
 373   if (!pushline(L, 1))
 374     return -1;  /* no input */
 375   if ((status = addreturn(L)) != LUA_OK)  /* 'return ...' did not work? */
 376     status = multiline(L);  /* try as command, maybe with continuation lines */
 377   lua_remove(L, 1);  /* remove line from the stack */
 378   lua_assert(lua_gettop(L) == 1);
 379   return status;
 380 }
 381
 382
 383 /*
 384 ** Prints (calling the Lua 'print' function) any values on the stack
 385 */
 386 static void l_print (lua_State *L) {
 387   int n = lua_gettop(L);
 388   if (n > 0) {  /* any result to be printed? */
 389     luaL_checkstack(L, LUA_MINSTACK, "too many results to print");
 390     lua_getglobal(L, "print");
 391     lua_insert(L, 1);
 392     if (lua_pcall(L, n, 0, 0) != LUA_OK)
 393       l_message(progname, lua_pushfstring(L, "error calling 'print' (%s)",
 394                                              lua_tostring(L, -1)));
 395   }
 396 }
 397
 398
 399 /*
 400 ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and
 401 ** print any results.
 402 */
 403 static void doREPL (lua_State *L) {
 404   int status;
 405   const char *oldprogname = progname;
 406   progname = NULL;  /* no 'progname' on errors in interactive mode */
 407   while ((status = loadline(L)) != -1) {
 408     if (status == LUA_OK)
 409       status = docall(L, 0, LUA_MULTRET);
 410     if (status == LUA_OK) l_print(L);
 411     else report(L, status);
 412   }
 413   lua_settop(L, 0);  /* clear stack */
 414   lua_writeline();
 415   progname = oldprogname;
 416 }
 417
 418
 419 /*
 420 ** Push on the stack the contents of table 'arg' from 1 to #arg
 421 */
 422 static int pushargs (lua_State *L) {
 423   int i, n;
 424   if (lua_getglobal(L, "arg") != LUA_TTABLE)
 425     luaL_error(L, "'arg' is not a table");
 426   n = (int)luaL_len(L, -1);
 427   luaL_checkstack(L, n + 3, "too many arguments to script");
 428   for (i = 1; i <= n; i++)
 429     lua_rawgeti(L, -i, i);
 430   lua_remove(L, -i);  /* remove table from the stack */
 431   return n;
 432 }
 433
 434
 435 static int handle_script (lua_State *L, char **argv) {
 436   int status;
 437   const char *fname = argv[0];
 438   if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0)
 439     fname = NULL;  /* stdin */
 440   status = luaL_loadfile(L, fname);
 441   if (status == LUA_OK) {
 442     int n = pushargs(L);  /* push arguments to script */
 443     status = docall(L, n, LUA_MULTRET);
 444   }
 445   return report(L, status);
 446 }
 447
 448
 449
 450 /* bits of various argument indicators in 'args' */
 451 #define has_error       1       /* bad option */
 452 #define has_i           2       /* -i */
 453 #define has_v           4       /* -v */
 454 #define has_e           8       /* -e */
 455 #define has_E           16      /* -E */
 456
 457 /*
 458 ** Traverses all arguments from 'argv', returning a mask with those
 459 ** needed before running any Lua code (or an error code if it finds
 460 ** any invalid argument). 'first' returns the first not-handled argument
 461 ** (either the script name or a bad argument in case of error).
 462 */
 463 static int collectargs (char **argv, int *first) {
 464   int args = 0;
 465   int i;
 466   for (i = 1; argv[i] != NULL; i++) {
 467     *first = i;
 468     if (argv[i][0] != '-')  /* not an option? */
 469         return args;  /* stop handling options */
 470     switch (argv[i][1]) {  /* else check option */
 471       case '-':  /* '--' */
 472         if (argv[i][2] != '\0')  /* extra characters after '--'? */
 473           return has_error;  /* invalid option */
 474         *first = i + 1;
 475         return args;
 476       case '\0':  /* '-' */
 477         return args;  /* script "name" is '-' */
 478       case 'E':
 479         if (argv[i][2] != '\0')  /* extra characters after 1st? */
 480           return has_error;  /* invalid option */
 481         args |= has_E;
 482         break;
 483       case 'i':
 484         args |= has_i;  /* (-i implies -v) *//* FALLTHROUGH */
 485       case 'v':
 486         if (argv[i][2] != '\0')  /* extra characters after 1st? */
 487           return has_error;  /* invalid option */
 488         args |= has_v;
 489         break;
 490       case 'e':
 491         args |= has_e;  /* FALLTHROUGH */
 492       case 'l':  /* both options need an argument */
 493         if (argv[i][2] == '\0') {  /* no concatenated argument? */
 494           i++;  /* try next 'argv' */
 495           if (argv[i] == NULL || argv[i][0] == '-')
 496             return has_error;  /* no next argument or it is another option */
 497         }
 498         break;
 499       default:  /* invalid option */
 500         return has_error;
 501     }
 502   }
 503   *first = i;  /* no script name */
 504   return args;
 505 }
 506
 507
 508 /*
 509 ** Processes options 'e' and 'l', which involve running Lua code.
 510 ** Returns 0 if some code raises an error.
 511 */
 512 static int runargs (lua_State *L, char **argv, int n) {
 513   int i;
 514   for (i = 1; i < n; i++) {
 515     int option = argv[i][1];
 516     lua_assert(argv[i][0] == '-');  /* already checked */
 517     if (option == 'e' || option == 'l') {
 518       int status;
 519       const char *extra = argv[i] + 2;  /* both options need an argument */
 520       if (*extra == '\0') extra = argv[++i];
 521       lua_assert(extra != NULL);
 522       status = (option == 'e')
 523                ? dostring(L, extra, "=(command line)")
 524                : dolibrary(L, extra);
 525       if (status != LUA_OK) return 0;
 526     }
 527   }
 528   return 1;
 529 }
 530
 531
 532 static int handle_luainit (lua_State *L) {
 533   const char *name = "=" LUA_INITVARVERSION;
 534   const char *init = getenv(name + 1);
 535   if (init == NULL) {
 536     name = "=" LUA_INIT_VAR;
 537     init = getenv(name + 1);  /* try alternative name */
 538   }
 539   if (init == NULL) return LUA_OK;
 540   else if (init[0] == '@')
 541     return dofile(L, init+1);
 542   else
 543     return dostring(L, init, name);
 544 }
 545
 546
 547 /*
 548 ** Main body of stand-alone interpreter (to be called in protected mode).
 549 ** Reads the options and handles them all.
 550 */
 551 static int pmain (lua_State *L) {
 552   int argc = (int)lua_tointeger(L, 1);
 553   char **argv = (char **)lua_touserdata(L, 2);
 554   int script;
 555   int args = collectargs(argv, &script);
 556   luaL_checkversion(L);  /* check that interpreter has correct version */
 557   if (argv[0] && argv[0][0]) progname = argv[0];
 558   if (args == has_error) {  /* bad arg? */
 559     print_usage(argv[script]);  /* 'script' has index of bad arg. */
 560     return 0;
 561   }
 562   if (args & has_v)  /* option '-v'? */
 563     print_version();
 564   if (args & has_E) {  /* option '-E'? */
 565     lua_pushboolean(L, 1);  /* signal for libraries to ignore env. vars. */
 566     lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
 567   }
 568   luaL_openlibs(L);  /* open standard libraries */
 569   createargtable(L, argv, argc, script);  /* create table 'arg' */
 570   if (!(args & has_E)) {  /* no option '-E'? */
 571     if (handle_luainit(L) != LUA_OK)  /* run LUA_INIT */
 572       return 0;  /* error running LUA_INIT */
 573   }
 574   if (!runargs(L, argv, script))  /* execute arguments -e and -l */
 575     return 0;  /* something failed */
 576   if (script < argc &&  /* execute main script (if there is one) */
 577       handle_script(L, argv + script) != LUA_OK)
 578     return 0;
 579   if (args & has_i)  /* -i option? */
 580     doREPL(L);  /* do read-eval-print loop */
 581   else if (script == argc && !(args & (has_e | has_v))) {  /* no arguments? */
 582     if (lua_stdin_is_tty()) {  /* running in interactive mode? */
 583       print_version();
 584       doREPL(L);  /* do read-eval-print loop */
 585     }
 586     else dofile(L, NULL);  /* executes stdin as a file */
 587   }
 588   lua_pushboolean(L, 1);  /* signal no errors */
 589   return 1;
 590 }
 591
 592
 593 int main (int argc, char **argv) {
 594   int status, result;
 595   lua_State *L = luaL_newstate();  /* create state */
 596   if (L == NULL) {
 597     l_message(argv[0], "cannot create state: not enough memory");
 598     return EXIT_FAILURE;
 599   }
 600   lua_pushcfunction(L, &pmain);  /* to call 'pmain' in protected mode */
 601   lua_pushinteger(L, argc);  /* 1st argument */
 602   lua_pushlightuserdata(L, argv); /* 2nd argument */
 603   status = lua_pcall(L, 2, 1, 0);  /* do the call */
 604   result = lua_toboolean(L, -1);  /* get result */
 605   report(L, status);
 606   lua_close(L);
 607   return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
 608 }
 609