lua.c
(5.1.5)
/*
** $Id: lua.c,v 1.160.1.2 2007/12/28 15:32:23 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"
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 (void) {
fprintf(stderr,
"usage: %s [options] [script [args]].\n"
"Available options are:\n"
" -e stat execute string " LUA_QL("stat") "\n"
" -l name require library " LUA_QL("name") "\n"
" -i enter interactive mode after executing " LUA_QL("script") "\n"
" -v show version information\n"
" -- stop handling options\n"
" - execute stdin and stop handling options\n"
,
progname);
fflush(stderr);
}
static void l_message (const char *pname, const char *msg) {
if (pname) fprintf(stderr, "%s: ", pname);
fprintf(stderr, "%s\n", msg);
fflush(stderr);
}
static int report (lua_State *L, int status) {
if (status && !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);
}
return status;
}
static int traceback (lua_State *L) {
if (!lua_isstring(L, 1)) /* 'message' not a string? */
return 1; /* keep it intact */
lua_getfield(L, LUA_GLOBALSINDEX, "debug");
if (!lua_istable(L, -1)) {
lua_pop(L, 1);
return 1;
}
lua_getfield(L, -1, "traceback");
if (!lua_isfunction(L, -1)) {
lua_pop(L, 2);
return 1;
}
lua_pushvalue(L, 1); /* pass error message */
lua_pushinteger(L, 2); /* skip this function and traceback */
lua_call(L, 2, 1); /* call debug.traceback */
return 1;
}
static int docall (lua_State *L, int narg, int clear) {
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 */
signal(SIGINT, laction);
status = lua_pcall(L, narg, (clear ? 0 : LUA_MULTRET), base);
signal(SIGINT, SIG_DFL);
lua_remove(L, base); /* remove traceback function */
/* force a complete garbage collection in case of errors */
if (status != 0) lua_gc(L, LUA_GCCOLLECT, 0);
return status;
}
static void print_version (void) {
l_message(NULL, LUA_RELEASE " " LUA_COPYRIGHT);
}
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) || docall(L, 0, 1);
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) || docall(L, 0, 1);
return report(L, status);
}
static int dolibrary (lua_State *L, const char *name) {
lua_getglobal(L, "require");
lua_pushstring(L, name);
return report(L, docall(L, 1, 1));
}
static const char *get_prompt (lua_State *L, int firstline) {
const char *p;
lua_getfield(L, LUA_GLOBALSINDEX, 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;
}
static int incomplete (lua_State *L, int status) {
if (status == LUA_ERRSYNTAX) {
size_t lmsg;
const char *msg = lua_tolstring(L, -1, &lmsg);
const char *tp = msg + lmsg - (sizeof(LUA_QL("<eof>")) - 1);
if (strstr(msg, LUA_QL("<eof>")) == tp) {
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 */
status = luaL_loadbuffer(L, lua_tostring(L, 1), lua_strlen(L, 1), "=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 == 0) status = docall(L, 0, 0);
report(L, status);
if (status == 0 && lua_gettop(L) > 0) { /* any result to print? */
lua_getglobal(L, "print");
lua_insert(L, 1);
if (lua_pcall(L, lua_gettop(L)-1, 0, 0) != 0)
l_message(progname, lua_pushfstring(L,
"error calling " LUA_QL("print") " (%s)",
lua_tostring(L, -1)));
}
}
lua_settop(L, 0); /* clear stack */
fputs("\n", stdout);
fflush(stdout);
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 == 0)
status = docall(L, narg, 0);
else
lua_pop(L, narg);
return report(L, status);
}
/* check that argument has no extra characters at the end */
#define notail(x) {if ((x)[2] != '\0') return -1;}
static int collectargs (char **argv, int *pi, int *pv, int *pe) {
int i;
for (i = 1; argv[i] != NULL; i++) {
if (argv[i][0] != '-') /* not an option? */
return i;
switch (argv[i][1]) { /* option */
case '-':
notail(argv[i]);
return (argv[i+1] != NULL ? i+1 : 0);
case '\0':
return i;
case 'i':
notail(argv[i]);
*pi = 1; /* go through */
case 'v':
notail(argv[i]);
*pv = 1;
break;
case 'e':
*pe = 1; /* go through */
case 'l':
if (argv[i][2] == '\0') {
i++;
if (argv[i] == NULL) return -1;
}
break;
default: return -1; /* invalid option */
}
}
return 0;
}
static int runargs (lua_State *L, char **argv, int n) {
int i;
for (i = 1; i < n; i++) {
if (argv[i] == NULL) continue;
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)") != 0)
return 1;
break;
}
case 'l': {
const char *filename = argv[i] + 2;
if (*filename == '\0') filename = argv[++i];
lua_assert(filename != NULL);
if (dolibrary(L, filename))
return 1; /* stop if file fails */
break;
}
default: break;
}
}
return 0;
}
static int handle_luainit (lua_State *L) {
const char *init = getenv(LUA_INIT);
if (init == NULL) return 0; /* status OK */
else if (init[0] == '@')
return dofile(L, init+1);
else
return dostring(L, init, "=" LUA_INIT);
}
struct Smain {
int argc;
char **argv;
int status;
};
static int pmain (lua_State *L) {
struct Smain *s = (struct Smain *)lua_touserdata(L, 1);
char **argv = s->argv;
int script;
int has_i = 0, has_v = 0, has_e = 0;
globalL = L;
if (argv[0] && argv[0][0]) progname = argv[0];
lua_gc(L, LUA_GCSTOP, 0); /* stop collector during initialization */
luaL_openlibs(L); /* open libraries */
lua_gc(L, LUA_GCRESTART, 0);
s->status = handle_luainit(L);
if (s->status != 0) return 0;
script = collectargs(argv, &has_i, &has_v, &has_e);
if (script < 0) { /* invalid args? */
print_usage();
s->status = 1;
return 0;
}
if (has_v) print_version();
s->status = runargs(L, argv, (script > 0) ? script : s->argc);
if (s->status != 0) return 0;
if (script)
s->status = handle_script(L, argv, script);
if (s->status != 0) return 0;
if (has_i)
dotty(L);
else if (script == 0 && !has_e && !has_v) {
if (lua_stdin_is_tty()) {
print_version();
dotty(L);
}
else dofile(L, NULL); /* executes stdin as a file */
}
return 0;
}
int main (int argc, char **argv) {
int status;
struct Smain s;
lua_State *L = lua_open(); /* create state */
if (L == NULL) {
l_message(argv[0], "cannot create state: not enough memory");
return EXIT_FAILURE;
}
s.argc = argc;
s.argv = argv;
status = lua_cpcall(L, &pmain, &s);
report(L, status);
lua_close(L);
return (status || s.status) ? EXIT_FAILURE : EXIT_SUCCESS;
}