/*** $Id: lua.c,v 1.205 2012/05/23 15:37:09 roberto Exp $** Lua stand-alone interpreter** See Copyright Notice in lua.h*/  #include <signal.h>#include <stdio.h>#include <stdlib.h>#include <string.h> #define lua_c #include "lua.h" #include "lauxlib.h"#include "lualib.h"  #if !defined(LUA_PROMPT)#define LUA_PROMPT		"> "#define LUA_PROMPT2		">> "#endif #if !defined(LUA_PROGNAME)#define LUA_PROGNAME		"lua"#endif #if !defined(LUA_MAXINPUT)#define LUA_MAXINPUT		512#endif #if !defined(LUA_INIT)#define LUA_INIT		"LUA_INIT"#endif #define LUA_INITVERSION  \	LUA_INIT "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR  /*** lua_stdin_is_tty detects whether the standard input is a 'tty' (that** is, whether we're running lua interactively).*/#if defined(LUA_USE_ISATTY)#include <unistd.h>#define lua_stdin_is_tty()	isatty(0)#elif defined(LUA_WIN)#include <io.h>#include <stdio.h>#define lua_stdin_is_tty()	_isatty(_fileno(stdin))#else#define lua_stdin_is_tty()	1  /* assume stdin is a tty */#endif  /*** lua_readline defines how to show a prompt and then read a line from** the standard input.** lua_saveline defines how to "save" a read line in a "history".** lua_freeline defines how to free a line read by lua_readline.*/#if defined(LUA_USE_READLINE) #include <stdio.h>#include <readline/readline.h>#include <readline/history.h>#define lua_readline(L,b,p)	((void)L, ((b)=readline(p)) != NULL)#define lua_saveline(L,idx) \        if (lua_rawlen(L,idx) > 0)  /* non-empty line? */ \          add_history(lua_tostring(L, idx));  /* add it to history */#define lua_freeline(L,b)	((void)L, free(b)) #elif !defined(lua_readline) #define lua_readline(L,b,p) \        ((void)L, fputs(p, stdout), fflush(stdout),  /* show prompt */ \        fgets(b, LUA_MAXINPUT, stdin) != NULL)  /* get line */#define lua_saveline(L,idx)	{ (void)L; (void)idx; }#define lua_freeline(L,b)	{ (void)L; (void)b; } #endif    static lua_State *globalL = NULL; static const char *progname = LUA_PROGNAME;   static void lstop (lua_State *L, lua_Debug *ar) {  (void)ar;  /* unused arg. */  lua_sethook(L, NULL, 0, 0);  luaL_error(L, "interrupted!");}  static void laction (int i) {  signal(i, SIG_DFL); /* if another SIGINT happens before lstop,                              terminate process (default action) */  lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);}  static void print_usage (const char *badoption) {  luai_writestringerror("%s: ", progname);  if (badoption[1] == 'e' || badoption[1] == 'l')    luai_writestringerror("'%s' needs argument\n", badoption);  else    luai_writestringerror("unrecognized option '%s'\n", badoption);  luai_writestringerror(  "usage: %s [options] [script [args]]\n"  "Available options are:\n"  "  -e stat  execute string " LUA_QL("stat") "\n"  "  -i       enter interactive mode after executing " LUA_QL("script") "\n"  "  -l name  require library " LUA_QL("name") "\n"  "  -v       show version information\n"  "  -E       ignore environment variables\n"  "  --       stop handling options\n"  "  -        stop handling options and execute stdin\n"  ,  progname);}  static void l_message (const char *pname, const char *msg) {  if (pname) luai_writestringerror("%s: ", pname);  luai_writestringerror("%s\n", msg);}  static int report (lua_State *L, int status) {  if (status != LUA_OK && !lua_isnil(L, -1)) {    const char *msg = lua_tostring(L, -1);    if (msg == NULL) msg = "(error object is not a string)";    l_message(progname, msg);    lua_pop(L, 1);    /* force a complete garbage collection in case of errors */    lua_gc(L, LUA_GCCOLLECT, 0);  }  return status;}  /* the next function is called unprotected, so it must avoid errors */static void finalreport (lua_State *L, int status) {  if (status != LUA_OK) {    const char *msg = (lua_type(L, -1) == LUA_TSTRING) ? lua_tostring(L, -1)                                                       : NULL;    if (msg == NULL) msg = "(error object is not a string)";    l_message(progname, msg);    lua_pop(L, 1);  }}  static int traceback (lua_State *L) {  const char *msg = lua_tostring(L, 1);  if (msg)    luaL_traceback(L, L, msg, 1);  else if (!lua_isnoneornil(L, 1)) {  /* is there an error object? */    if (!luaL_callmeta(L, 1, "__tostring"))  /* try its 'tostring' metamethod */      lua_pushliteral(L, "(no error message)");  }  return 1;}  static int docall (lua_State *L, int narg, int nres) {  int status;  int base = lua_gettop(L) - narg;  /* function index */  lua_pushcfunction(L, traceback);  /* push traceback function */  lua_insert(L, base);  /* put it under chunk and args */  globalL = L;  /* to be available to 'laction' */  signal(SIGINT, laction);  status = lua_pcall(L, narg, nres, base);  signal(SIGINT, SIG_DFL);  lua_remove(L, base);  /* remove traceback function */  return status;}  static void print_version (void) {  luai_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT));  luai_writeline();}  static int getargs (lua_State *L, char **argv, int n) {  int narg;  int i;  int argc = 0;  while (argv[argc]) argc++;  /* count total number of arguments */  narg = argc - (n + 1);  /* number of arguments to the script */  luaL_checkstack(L, narg + 3, "too many arguments to script");  for (i=n+1; i < argc; i++)    lua_pushstring(L, argv[i]);  lua_createtable(L, narg, n + 1);  for (i=0; i < argc; i++) {    lua_pushstring(L, argv[i]);    lua_rawseti(L, -2, i - n);  }  return narg;}  static int dofile (lua_State *L, const char *name) {  int status = luaL_loadfile(L, name);  if (status == LUA_OK) status = docall(L, 0, 0);  return report(L, status);}  static int dostring (lua_State *L, const char *s, const char *name) {  int status = luaL_loadbuffer(L, s, strlen(s), name);  if (status == LUA_OK) status = docall(L, 0, 0);  return report(L, status);}  static int dolibrary (lua_State *L, const char *name) {  int status;  lua_getglobal(L, "require");  lua_pushstring(L, name);  status = docall(L, 1, 1);  /* call 'require(name)' */  if (status == LUA_OK)    lua_setglobal(L, name);  /* global[name] = require return */  return report(L, status);}  static const char *get_prompt (lua_State *L, int firstline) {  const char *p;  lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2");  p = lua_tostring(L, -1);  if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);  lua_pop(L, 1);  /* remove global */  return p;} /* mark in error messages for incomplete statements */#define EOFMARK		"<eof>"#define marklen		(sizeof(EOFMARK)/sizeof(char) - 1) static int incomplete (lua_State *L, int status) {  if (status == LUA_ERRSYNTAX) {    size_t lmsg;    const char *msg = lua_tolstring(L, -1, &lmsg);    if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) {      lua_pop(L, 1);      return 1;    }  }  return 0;  /* else... */}  static int pushline (lua_State *L, int firstline) {  char buffer[LUA_MAXINPUT];  char *b = buffer;  size_t l;  const char *prmt = get_prompt(L, firstline);  if (lua_readline(L, b, prmt) == 0)    return 0;  /* no input */  l = strlen(b);  if (l > 0 && b[l-1] == '\n')  /* line ends with newline? */    b[l-1] = '\0';  /* remove it */  if (firstline && b[0] == '=')  /* first line starts with `=' ? */    lua_pushfstring(L, "return %s", b+1);  /* change it to `return' */  else    lua_pushstring(L, b);  lua_freeline(L, b);  return 1;}  static int loadline (lua_State *L) {  int status;  lua_settop(L, 0);  if (!pushline(L, 1))    return -1;  /* no input */  for (;;) {  /* repeat until gets a complete line */    size_t l;    const char *line = lua_tolstring(L, 1, &l);    status = luaL_loadbuffer(L, line, l, "=stdin");    if (!incomplete(L, status)) break;  /* cannot try to add lines? */    if (!pushline(L, 0))  /* no more input? */      return -1;    lua_pushliteral(L, "\n");  /* add a new line... */    lua_insert(L, -2);  /* ...between the two lines */    lua_concat(L, 3);  /* join them */  }  lua_saveline(L, 1);  lua_remove(L, 1);  /* remove line */  return status;}  static void dotty (lua_State *L) {  int status;  const char *oldprogname = progname;  progname = NULL;  while ((status = loadline(L)) != -1) {    if (status == LUA_OK) status = docall(L, 0, LUA_MULTRET);    report(L, status);    if (status == LUA_OK && lua_gettop(L) > 0) {  /* any result to print? */      luaL_checkstack(L, LUA_MINSTACK, "too many results to print");      lua_getglobal(L, "print");      lua_insert(L, 1);      if (lua_pcall(L, lua_gettop(L)-1, 0, 0) != LUA_OK)        l_message(progname, lua_pushfstring(L,                               "error calling " LUA_QL("print") " (%s)",                               lua_tostring(L, -1)));    }  }  lua_settop(L, 0);  /* clear stack */  luai_writeline();  progname = oldprogname;}  static int handle_script (lua_State *L, char **argv, int n) {  int status;  const char *fname;  int narg = getargs(L, argv, n);  /* collect arguments */  lua_setglobal(L, "arg");  fname = argv[n];  if (strcmp(fname, "-") == 0 && strcmp(argv[n-1], "--") != 0)    fname = NULL;  /* stdin */  status = luaL_loadfile(L, fname);  lua_insert(L, -(narg+1));  if (status == LUA_OK)    status = docall(L, narg, LUA_MULTRET);  else    lua_pop(L, narg);  return report(L, status);}  /* check that argument has no extra characters at the end */#define noextrachars(x)		{if ((x)[2] != '\0') return -1;}  /* indices of various argument indicators in array args */#define has_i		0	/* -i */#define has_v		1	/* -v */#define has_e		2	/* -e */#define has_E		3	/* -E */ #define num_has		4	/* number of 'has_*' */  static int collectargs (char **argv, int *args) {  int i;  for (i = 1; argv[i] != NULL; i++) {    if (argv[i][0] != '-')  /* not an option? */        return i;    switch (argv[i][1]) {  /* option */      case '-':        noextrachars(argv[i]);        return (argv[i+1] != NULL ? i+1 : 0);      case '\0':        return i;      case 'E':        args[has_E] = 1;        break;      case 'i':        noextrachars(argv[i]);        args[has_i] = 1;  /* go through */      case 'v':        noextrachars(argv[i]);        args[has_v] = 1;        break;      case 'e':        args[has_e] = 1;  /* go through */      case 'l':  /* both options need an argument */        if (argv[i][2] == '\0') {  /* no concatenated argument? */          i++;  /* try next 'argv' */          if (argv[i] == NULL || argv[i][0] == '-')            return -(i - 1);  /* no next argument or it is another option */        }        break;      default:  /* invalid option; return its index... */        return -i;  /* ...as a negative value */    }  }  return 0;}  static int runargs (lua_State *L, char **argv, int n) {  int i;  for (i = 1; i < n; i++) {    lua_assert(argv[i][0] == '-');    switch (argv[i][1]) {  /* option */      case 'e': {        const char *chunk = argv[i] + 2;        if (*chunk == '\0') chunk = argv[++i];        lua_assert(chunk != NULL);        if (dostring(L, chunk, "=(command line)") != LUA_OK)          return 0;        break;      }      case 'l': {        const char *filename = argv[i] + 2;        if (*filename == '\0') filename = argv[++i];        lua_assert(filename != NULL);        if (dolibrary(L, filename) != LUA_OK)          return 0;  /* stop if file fails */        break;      }      default: break;    }  }  return 1;}  static int handle_luainit (lua_State *L) {  const char *name = "=" LUA_INITVERSION;  const char *init = getenv(name + 1);  if (init == NULL) {    name = "=" LUA_INIT;    init = getenv(name + 1);  /* try alternative name */  }  if (init == NULL) return LUA_OK;  else if (init[0] == '@')    return dofile(L, init+1);  else    return dostring(L, init, name);}  static int pmain (lua_State *L) {  int argc = (int)lua_tointeger(L, 1);  char **argv = (char **)lua_touserdata(L, 2);  int script;  int args[num_has];  args[has_i] = args[has_v] = args[has_e] = args[has_E] = 0;  if (argv[0] && argv[0][0]) progname = argv[0];  script = collectargs(argv, args);  if (script < 0) {  /* invalid arg? */    print_usage(argv[-script]);    return 0;  }  if (args[has_v]) print_version();  if (args[has_E]) {  /* option '-E'? */    lua_pushboolean(L, 1);  /* signal for libraries to ignore env. vars. */    lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");  }  /* open standard libraries */  luaL_checkversion(L);  lua_gc(L, LUA_GCSTOP, 0);  /* stop collector during initialization */  luaL_openlibs(L);  /* open libraries */  lua_gc(L, LUA_GCRESTART, 0);  if (!args[has_E] && handle_luainit(L) != LUA_OK)    return 0;  /* error running LUA_INIT */  /* execute arguments -e and -l */  if (!runargs(L, argv, (script > 0) ? script : argc)) return 0;  /* execute main script (if there is one) */  if (script && handle_script(L, argv, script) != LUA_OK) return 0;  if (args[has_i])  /* -i option? */    dotty(L);  else if (script == 0 && !args[has_e] && !args[has_v]) {  /* no arguments? */    if (lua_stdin_is_tty()) {      print_version();      dotty(L);    }    else dofile(L, NULL);  /* executes stdin as a file */  }  lua_pushboolean(L, 1);  /* signal no errors */  return 1;}  int main (int argc, char **argv) {  int status, result;  lua_State *L = luaL_newstate();  /* create state */  if (L == NULL) {    l_message(argv[0], "cannot create state: not enough memory");    return EXIT_FAILURE;  }  /* call 'pmain' in protected mode */  lua_pushcfunction(L, &pmain);  lua_pushinteger(L, argc);  /* 1st argument */  lua_pushlightuserdata(L, argv); /* 2nd argument */  status = lua_pcall(L, 2, 1, 0);  result = lua_toboolean(L, -1);  /* get result */  finalreport(L, status);  lua_close(L);  return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;}