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LUA/src/LUA.c

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/*
** $Id: LUA.c,v 1.206 2012/09/29 20:07:06 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);
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);
int readstatus = LUA_readline(L, b, prmt);
LUA_pop(L, 1); /* remove result from 'get_prompt' */
if (readstatus == 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;
}
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