ruby.c

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/**********************************************************************

  ruby.c -

  $Author: yugui $
  created at: Tue Aug 10 12:47:31 JST 1993

  Copyright (C) 1993-2007 Yukihiro Matsumoto
  Copyright (C) 2000  Network Applied Communication Laboratory, Inc.
  Copyright (C) 2000  Information-technology Promotion Agency, Japan

**********************************************************************/

#ifdef __CYGWIN__
#include <windows.h>
#include <sys/cygwin.h>
#endif
#include "ruby/ruby.h"
#include "ruby/encoding.h"
#include "eval_intern.h"
#include "dln.h"
#include <stdio.h>
#include <sys/types.h>
#include <ctype.h>

#ifdef __hpux
#include <sys/pstat.h>
#endif
#if defined(LOAD_RELATIVE) && defined(HAVE_DLADDR)
#include <dlfcn.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#if defined(HAVE_FCNTL_H)
#include <fcntl.h>
#elif defined(HAVE_SYS_FCNTL_H)
#include <sys/fcntl.h>
#endif
#ifdef HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif
#ifndef MAXPATHLEN
# define MAXPATHLEN 1024
#endif

#include "ruby/util.h"

#ifndef HAVE_STDLIB_H
char *getenv();
#endif

VALUE rb_parser_get_yydebug(VALUE);
VALUE rb_parser_set_yydebug(VALUE, VALUE);

const char *ruby_get_inplace_mode(void);
void ruby_set_inplace_mode(const char *);

#define DISABLE_BIT(bit) (1U << disable_##bit)
enum disable_flag_bits {
    disable_gems,
    disable_rubyopt,
    disable_flag_count
};

#define DUMP_BIT(bit) (1U << dump_##bit)
enum dump_flag_bits {
    dump_version,
    dump_copyright,
    dump_usage,
    dump_yydebug,
    dump_syntax,
    dump_parsetree,
    dump_parsetree_with_comment,
    dump_insns,
    dump_flag_count
};

struct cmdline_options {
    int sflag, xflag;
    int do_loop, do_print;
    int do_line, do_split;
    int do_search;
    unsigned int disable;
    int verbose;
    int safe_level;
    unsigned int setids;
    unsigned int dump;
    const char *script;
    VALUE script_name;
    VALUE e_script;
    struct {
        struct {
            VALUE name;
            int index;
        } enc;
    } src, ext, intern;
    VALUE req_list;
};

static void init_ids(struct cmdline_options *);

#define src_encoding_index GET_VM()->src_encoding_index

static struct cmdline_options *
cmdline_options_init(struct cmdline_options *opt)
{
    MEMZERO(opt, *opt, 1);
    init_ids(opt);
    opt->src.enc.index = src_encoding_index;
    opt->ext.enc.index = -1;
    opt->intern.enc.index = -1;
    return opt;
}

static NODE *load_file(VALUE, const char *, int, struct cmdline_options *);
static void forbid_setid(const char *, struct cmdline_options *);
#define forbid_setid(s) forbid_setid(s, opt)

static struct {
    int argc;
    char **argv;
#if !defined(PSTAT_SETCMD) && !defined(HAVE_SETPROCTITLE)
    size_t len;
#endif
} origarg;

static void
usage(const char *name)
{
    /* This message really ought to be max 23 lines.
     * Removed -h because the user already knows that option. Others? */

    static const char *const usage_msg[] = {
        "-0[octal]       specify record separator (\\0, if no argument)",
        "-a              autosplit mode with -n or -p (splits $_ into $F)",
        "-c              check syntax only",
        "-Cdirectory     cd to directory, before executing your script",
        "-d              set debugging flags (set $DEBUG to true)",
        "-e 'command'    one line of script. Several -e's allowed. Omit [programfile]",
        "-Eex[:in]       specify the default external and internal character encodings",
        "-Fpattern       split() pattern for autosplit (-a)",
        "-i[extension]   edit ARGV files in place (make backup if extension supplied)",
        "-Idirectory     specify $LOAD_PATH directory (may be used more than once)",
        "-l              enable line ending processing",
        "-n              assume 'while gets(); ... end' loop around your script",
        "-p              assume loop like -n but print line also like sed",
        "-rlibrary       require the library, before executing your script",
        "-s              enable some switch parsing for switches after script name",
        "-S              look for the script using PATH environment variable",
        "-T[level=1]     turn on tainting checks",
        "-v              print version number, then turn on verbose mode",
        "-w              turn warnings on for your script",
        "-W[level=2]     set warning level; 0=silence, 1=medium, 2=verbose",
        "-x[directory]   strip off text before #!ruby line and perhaps cd to directory",
        "--copyright     print the copyright",
        "--version       print the version",
        NULL
    };
    const char *const *p = usage_msg;

    printf("Usage: %s [switches] [--] [programfile] [arguments]\n", name);
    while (*p)
        printf("  %s\n", *p++);
}

VALUE rb_get_load_path(void);

#ifdef MANGLED_PATH
static VALUE
rubylib_mangled_path(const char *s, unsigned int l)
{
    static char *newp, *oldp;
    static int newl, oldl, notfound;
    char *ptr;
    VALUE ret;

    if (!newp && !notfound) {
        newp = getenv("RUBYLIB_PREFIX");
        if (newp) {
            oldp = newp = strdup(newp);
            while (*newp && !ISSPACE(*newp) && *newp != ';') {
                newp = CharNext(newp);  /* Skip digits. */
            }
            oldl = newp - oldp;
            while (*newp && (ISSPACE(*newp) || *newp == ';')) {
                newp = CharNext(newp);  /* Skip whitespace. */
            }
            newl = strlen(newp);
            if (newl == 0 || oldl == 0) {
                rb_fatal("malformed RUBYLIB_PREFIX");
            }
            translit_char(newp, '\\', '/');
        }
        else {
            notfound = 1;
        }
    }
    if (!newp || l < oldl || STRNCASECMP(oldp, s, oldl) != 0) {
        return rb_str_new(s, l);
    }
    ret = rb_str_new(0, l + newl - oldl);
    ptr = RSTRING_PTR(ret);
    memcpy(ptr, newp, newl);
    memcpy(ptr + newl, s + oldl, l - oldl);
    ptr[l + newl - oldl] = 0;
    return ret;
}
#else
#define rubylib_mangled_path rb_str_new
#endif

static void
push_include(const char *path, VALUE (*filter)(VALUE))
{
    const char sep = PATH_SEP_CHAR;
    const char *p, *s;
    VALUE load_path = GET_VM()->load_path;

    p = path;
    while (*p) {
        while (*p == sep)
            p++;
        if (!*p) break;
        for (s = p; *s && *s != sep; s = CharNext(s));
        rb_ary_push(load_path, (*filter)(rubylib_mangled_path(p, s - p)));
        p = s;
    }
}

#ifdef __CYGWIN__
static void
push_include_cygwin(const char *path, VALUE (*filter)(VALUE))
{
    const char *p, *s;
    char rubylib[FILENAME_MAX];
    VALUE buf = 0;

    p = path;
    while (*p) {
        unsigned int len;
        while (*p == ';')
            p++;
        if (!*p) break;
        for (s = p; *s && *s != ';'; s = CharNext(s));
        len = s - p;
        if (*s) {
            if (!buf) {
                buf = rb_str_new(p, len);
                p = RSTRING_PTR(buf);
            }
            else {
                rb_str_resize(buf, len);
                p = strncpy(RSTRING_PTR(buf), p, len);
            }
        }
        if (cygwin_conv_to_posix_path(p, rubylib) == 0)
            p = rubylib;
        push_include(p, filter);
        if (!*s) break;
        p = s + 1;
    }
}

#define push_include push_include_cygwin
#endif

void
ruby_push_include(const char *path, VALUE (*filter)(VALUE))
{
    if (path == 0)
        return;
    push_include(path, filter);
}

static VALUE
identical_path(VALUE path)
{
    return path;
}
static VALUE
locale_path(VALUE path)
{
    rb_enc_associate(path, rb_locale_encoding());
    return path;
}

void
ruby_incpush(const char *path)
{
    ruby_push_include(path, locale_path);
}

static VALUE
expand_include_path(VALUE path)
{
    char *p = RSTRING_PTR(path);
    if (!p)
        return path;
    if (*p == '.' && p[1] == '/')
        return path;
    return rb_file_expand_path(path, Qnil);
}

void
ruby_incpush_expand(const char *path)
{
    ruby_push_include(path, expand_include_path);
}

#if defined _WIN32 || defined __CYGWIN__
static HMODULE libruby;

BOOL WINAPI
DllMain(HINSTANCE dll, DWORD reason, LPVOID reserved)
{
    if (reason == DLL_PROCESS_ATTACH)
        libruby = dll;
    return TRUE;
}

HANDLE
rb_libruby_handle(void)
{
    return libruby;
}
#endif

void ruby_init_loadpath_safe(int safe_level);

void
ruby_init_loadpath(void)
{
    ruby_init_loadpath_safe(0);
}

void
ruby_init_loadpath_safe(int safe_level)
{
    VALUE load_path;
    ID id_initial_load_path_mark;
    extern const char ruby_initial_load_paths[];
    const char *paths = ruby_initial_load_paths;
#if defined LOAD_RELATIVE
# if defined HAVE_DLADDR || (defined __CYGWIN__ && defined CCP_WIN_A_TO_POSIX)
#   define VARIABLE_LIBPATH 1
# else
#   define VARIABLE_LIBPATH 0
# endif
# if VARIABLE_LIBPATH
    char *libpath;
    VALUE sopath;
# else
    char libpath[MAXPATHLEN + 1];
# endif
    size_t baselen;
    char *p;

#if defined _WIN32 || defined __CYGWIN__
# if VARIABLE_LIBPATH
    sopath = rb_str_new(0, MAXPATHLEN);
    libpath = RSTRING_PTR(sopath);
    GetModuleFileName(libruby, libpath, MAXPATHLEN);
# else
    GetModuleFileName(libruby, libpath, sizeof libpath);
# endif
#elif defined(__EMX__)
    _execname(libpath, sizeof(libpath) - 1);
#elif defined(HAVE_DLADDR)
    Dl_info dli;
    if (dladdr((void *)(VALUE)expand_include_path, &dli)) {
        VALUE fname = rb_str_new_cstr(dli.dli_fname);
        sopath = rb_file_absolute_path(fname, Qnil);
        rb_str_resize(fname, 0);
    }
    else {
        sopath = rb_str_new(0, 0);
    }
    libpath = RSTRING_PTR(sopath);
#endif

#if !VARIABLE_LIBPATH
    libpath[sizeof(libpath) - 1] = '\0';
#endif
#if defined DOSISH
    translit_char(libpath, '\\', '/');
#elif defined __CYGWIN__
    {
# if VARIABLE_LIBPATH
        const int win_to_posix = CCP_WIN_A_TO_POSIX | CCP_RELATIVE;
        size_t newsize = cygwin_conv_path(win_to_posix, libpath, 0, 0);
        if (newsize > 0) {
            VALUE rubylib = rb_str_new(0, newsize);
            p = RSTRING_PTR(rubylib);
            if (cygwin_conv_path(win_to_posix, libpath, p, newsize) == 0) {
                rb_str_resize(sopath, 0);
                sopath = rubylib;
                libpath = p;
            }
        }
# else
        char rubylib[FILENAME_MAX];
        cygwin_conv_to_posix_path(libpath, rubylib);
        strncpy(libpath, rubylib, sizeof(libpath));
# endif
    }
#endif
    p = strrchr(libpath, '/');
    if (p) {
        *p = 0;
        if (p - libpath > 3 && !(STRCASECMP(p - 4, "/bin") && strcmp(p - 4, "/lib"))) {
            p -= 4;
            *p = 0;
        }
    }
#if !VARIABLE_LIBPATH
    else {
        strlcpy(libpath, ".", sizeof(libpath));
        p = libpath + 1;
    }
    baselen = p - libpath;
#define PREFIX_PATH() rb_str_new(libpath, baselen)
#else
    baselen = p - libpath;
    rb_str_set_len(sopath, baselen);
    libpath = RSTRING_PTR(sopath);
#define PREFIX_PATH() sopath
#endif

#define BASEPATH() rb_str_buf_cat(rb_str_buf_new(baselen+len), libpath, baselen)

#define RUBY_RELATIVE(path, len) rb_str_buf_cat(BASEPATH(), path, len)
#else
    static const char exec_prefix[] = RUBY_EXEC_PREFIX;
#define RUBY_RELATIVE(path, len) rubylib_mangled_path(path, len)
#define PREFIX_PATH() RUBY_RELATIVE(exec_prefix, sizeof(exec_prefix)-1)
#endif
    load_path = GET_VM()->load_path;

    if (safe_level == 0) {
        ruby_push_include(getenv("RUBYLIB"), identical_path);
    }

    id_initial_load_path_mark = rb_intern_const("@gem_prelude_index");
    while (*paths) {
        size_t len = strlen(paths);
        VALUE path = RUBY_RELATIVE(paths, len);
        rb_ivar_set(path, id_initial_load_path_mark, path);
        rb_ary_push(load_path, path);
        paths += len + 1;
    }

    rb_const_set(rb_cObject, rb_intern_const("TMP_RUBY_PREFIX"), rb_obj_freeze(PREFIX_PATH()));
}


static void
add_modules(VALUE *req_list, const char *mod)
{
    VALUE list = *req_list;

    if (!list) {
        *req_list = list = rb_ary_new();
        RBASIC(list)->klass = 0;
    }
    rb_ary_push(list, rb_obj_freeze(rb_str_new2(mod)));
}

extern void Init_ext(void);
extern VALUE rb_vm_top_self(void);

static void
require_libraries(VALUE *req_list)
{
    VALUE list = *req_list;
    ID require;
    rb_thread_t *th = GET_THREAD();
    rb_block_t *prev_base_block = th->base_block;
    int prev_parse_in_eval = th->parse_in_eval;
    th->base_block = 0;
    th->parse_in_eval = 0;

    Init_ext();         /* should be called here for some reason :-( */
    CONST_ID(require, "require");
    while (list && RARRAY_LEN(list) > 0) {
        VALUE feature = rb_ary_shift(list);
        rb_funcall2(rb_vm_top_self(), require, 1, &feature);
    }
    *req_list = 0;

    th->parse_in_eval = prev_parse_in_eval;
    th->base_block = prev_base_block;
}

static void
process_sflag(int *sflag)
{
    if (*sflag > 0) {
        long n;
        VALUE *args;
        VALUE argv = rb_argv;

        n = RARRAY_LEN(argv);
        args = RARRAY_PTR(argv);
        while (n > 0) {
            VALUE v = *args++;
            char *s = StringValuePtr(v);
            char *p;
            int hyphen = FALSE;

            if (s[0] != '-')
                break;
            n--;
            if (s[1] == '-' && s[2] == '\0')
                break;

            v = Qtrue;
            /* check if valid name before replacing - with _ */
            for (p = s + 1; *p; p++) {
                if (*p == '=') {
                    *p++ = '\0';
                    v = rb_str_new2(p);
                    break;
                }
                if (*p == '-') {
                    hyphen = TRUE;
                }
                else if (*p != '_' && !ISALNUM(*p)) {
                    VALUE name_error[2];
                    name_error[0] =
                        rb_str_new2("invalid name for global variable - ");
                    if (!(p = strchr(p, '='))) {
                        rb_str_cat2(name_error[0], s);
                    }
                    else {
                        rb_str_cat(name_error[0], s, p - s);
                    }
                    name_error[1] = args[-1];
                    rb_exc_raise(rb_class_new_instance(2, name_error, rb_eNameError));
                }
            }
            s[0] = '$';
            if (hyphen) {
                for (p = s + 1; *p; ++p) {
                    if (*p == '-')
                        *p = '_';
                }
            }
            rb_gv_set(s, v);
        }
        n = RARRAY_LEN(argv) - n;
        while (n--) {
            rb_ary_shift(argv);
        }
        *sflag = -1;
    }
}

NODE *rb_parser_append_print(VALUE, NODE *);
NODE *rb_parser_while_loop(VALUE, NODE *, int, int);
static long proc_options(long argc, char **argv, struct cmdline_options *opt, int envopt);

static void
moreswitches(const char *s, struct cmdline_options *opt, int envopt)
{
    long argc, i, len;
    char **argv, *p;
    const char *ap = 0;
    VALUE argstr, argary;

    while (ISSPACE(*s)) s++;
    if (!*s) return;
    argstr = rb_str_tmp_new((len = strlen(s)) + 2);
    argary = rb_str_tmp_new(0);

    p = RSTRING_PTR(argstr);
    *p++ = ' ';
    memcpy(p, s, len + 1);
    ap = 0;
    rb_str_cat(argary, (char *)&ap, sizeof(ap));
    while (*p) {
        ap = p;
        rb_str_cat(argary, (char *)&ap, sizeof(ap));
        while (*p && !ISSPACE(*p)) ++p;
        if (!*p) break;
        *p++ = '\0';
        while (ISSPACE(*p)) ++p;
    }
    argc = RSTRING_LEN(argary) / sizeof(ap);
    ap = 0;
    rb_str_cat(argary, (char *)&ap, sizeof(ap));
    argv = (char **)RSTRING_PTR(argary);

    while ((i = proc_options(argc, argv, opt, envopt)) > 1 && (argc -= i) > 0) {
        argv += i;
        if (**argv != '-') {
            *--*argv = '-';
        }
        if ((*argv)[1]) {
            ++argc;
            --argv;
        }
    }

    /* get rid of GC */
    rb_str_resize(argary, 0);
    rb_str_resize(argstr, 0);
}

#define NAME_MATCH_P(name, str, len) \
    ((len) < (int)sizeof(name) && strncmp((str), name, (len)) == 0)

#define UNSET_WHEN(name, bit, str, len) \
    if (NAME_MATCH_P(name, str, len)) { \
        *(unsigned int *)arg &= ~(bit); \
        return;                         \
    }

#define SET_WHEN(name, bit, str, len)   \
    if (NAME_MATCH_P(name, str, len)) { \
        *(unsigned int *)arg |= (bit);  \
        return;                         \
    }

static void
enable_option(const char *str, int len, void *arg)
{
#define UNSET_WHEN_DISABLE(bit) UNSET_WHEN(#bit, DISABLE_BIT(bit), str, len)
    UNSET_WHEN_DISABLE(gems);
    UNSET_WHEN_DISABLE(rubyopt);
    if (NAME_MATCH_P("all", str, len)) {
        *(unsigned int *)arg = 0U;
        return;
    }
    rb_warn("unknown argument for --enable: `%.*s'", len, str);
}

static void
disable_option(const char *str, int len, void *arg)
{
#define SET_WHEN_DISABLE(bit) SET_WHEN(#bit, DISABLE_BIT(bit), str, len)
    SET_WHEN_DISABLE(gems);
    SET_WHEN_DISABLE(rubyopt);
    if (NAME_MATCH_P("all", str, len)) {
        *(unsigned int *)arg = ~0U;
        return;
    }
    rb_warn("unknown argument for --disable: `%.*s'", len, str);
}

static void
dump_option(const char *str, int len, void *arg)
{
#define SET_WHEN_DUMP(bit) SET_WHEN(#bit, DUMP_BIT(bit), str, len)
    SET_WHEN_DUMP(version);
    SET_WHEN_DUMP(copyright);
    SET_WHEN_DUMP(usage);
    SET_WHEN_DUMP(yydebug);
    SET_WHEN_DUMP(syntax);
    SET_WHEN_DUMP(parsetree);
    SET_WHEN_DUMP(parsetree_with_comment);
    SET_WHEN_DUMP(insns);
    rb_warn("don't know how to dump `%.*s',", len, str);
    rb_warn("but only [version, copyright, usage, yydebug, syntax, parsetree, parsetree_with_comment, insns].");
}

static void
set_option_encoding_once(const char *type, VALUE *name, const char *e, long elen)
{
    VALUE ename;

    if (!elen) elen = strlen(e);
    ename = rb_str_new(e, elen);

    if (*name &&
        rb_funcall(ename, rb_intern("casecmp"), 1, *name) != INT2FIX(0)) {
        rb_raise(rb_eRuntimeError,
                 "%s already set to %s", type, RSTRING_PTR(*name));
    }
    *name = ename;
}

#define set_internal_encoding_once(opt, e, elen) \
    set_option_encoding_once("default_internal", &opt->intern.enc.name, e, elen)
#define set_external_encoding_once(opt, e, elen) \
    set_option_encoding_once("default_external", &opt->ext.enc.name, e, elen)
#define set_source_encoding_once(opt, e, elen) \
    set_option_encoding_once("source", &opt->src.enc.name, e, elen)

static long
proc_options(long argc, char **argv, struct cmdline_options *opt, int envopt)
{
    long n, argc0 = argc;
    const char *s;

    if (argc == 0)
        return 0;

    for (argc--, argv++; argc > 0; argc--, argv++) {
        const char *const arg = argv[0];
        if (arg[0] != '-' || !arg[1])
            break;

        s = arg + 1;
      reswitch:
        switch (*s) {
          case 'a':
            if (envopt) goto noenvopt;
            opt->do_split = TRUE;
            s++;
            goto reswitch;

          case 'p':
            if (envopt) goto noenvopt;
            opt->do_print = TRUE;
            /* through */
          case 'n':
            if (envopt) goto noenvopt;
            opt->do_loop = TRUE;
            s++;
            goto reswitch;

          case 'd':
            ruby_debug = Qtrue;
            ruby_verbose = Qtrue;
            s++;
            goto reswitch;

          case 'y':
            if (envopt) goto noenvopt;
            opt->dump |= DUMP_BIT(yydebug);
            s++;
            goto reswitch;

          case 'v':
            if (opt->verbose) {
                s++;
                goto reswitch;
            }
            ruby_show_version();
            opt->verbose = 1;
          case 'w':
            ruby_verbose = Qtrue;
            s++;
            goto reswitch;

          case 'W':
            {
                size_t numlen;
                int v = 2;      /* -W as -W2 */

                if (*++s) {
                    v = scan_oct(s, 1, &numlen);
                    if (numlen == 0)
                        v = 1;
                    s += numlen;
                }
                switch (v) {
                  case 0:
                    ruby_verbose = Qnil;
                    break;
                  case 1:
                    ruby_verbose = Qfalse;
                    break;
                  default:
                    ruby_verbose = Qtrue;
                    break;
                }
            }
            goto reswitch;

          case 'c':
            if (envopt) goto noenvopt;
            opt->dump |= DUMP_BIT(syntax);
            s++;
            goto reswitch;

          case 's':
            if (envopt) goto noenvopt;
            forbid_setid("-s");
            if (!opt->sflag) opt->sflag = 1;
            s++;
            goto reswitch;

          case 'h':
            if (envopt) goto noenvopt;
            opt->dump |= DUMP_BIT(usage);
            goto switch_end;

          case 'l':
            if (envopt) goto noenvopt;
            opt->do_line = TRUE;
            rb_output_rs = rb_rs;
            s++;
            goto reswitch;

          case 'S':
            if (envopt) goto noenvopt;
            forbid_setid("-S");
            opt->do_search = TRUE;
            s++;
            goto reswitch;

          case 'e':
            if (envopt) goto noenvopt;
            forbid_setid("-e");
            if (!*++s) {
                s = argv[1];
                argc--, argv++;
            }
            if (!s) {
                rb_raise(rb_eRuntimeError, "no code specified for -e");
            }
            if (!opt->e_script) {
                opt->e_script = rb_str_new(0, 0);
                if (opt->script == 0)
                    opt->script = "-e";
            }
            rb_str_cat2(opt->e_script, s);
            rb_str_cat2(opt->e_script, "\n");
            break;

          case 'r':
            forbid_setid("-r");
            if (*++s) {
                add_modules(&opt->req_list, s);
            }
            else if (argv[1]) {
                add_modules(&opt->req_list, argv[1]);
                argc--, argv++;
            }
            break;

          case 'i':
            if (envopt) goto noenvopt;
            forbid_setid("-i");
            ruby_set_inplace_mode(s + 1);
            break;

          case 'x':
            if (envopt) goto noenvopt;
            opt->xflag = TRUE;
            s++;
            if (*s && chdir(s) < 0) {
                rb_fatal("Can't chdir to %s", s);
            }
            break;

          case 'C':
          case 'X':
            if (envopt) goto noenvopt;
            s++;
            if (!*s) {
                s = argv[1];
                argc--, argv++;
            }
            if (!s || !*s) {
                rb_fatal("Can't chdir");
            }
            if (chdir(s) < 0) {
                rb_fatal("Can't chdir to %s", s);
            }
            break;

          case 'F':
            if (envopt) goto noenvopt;
            if (*++s) {
                rb_fs = rb_reg_new(s, strlen(s), 0);
            }
            break;

          case 'E':
            if (!*++s && (!--argc || !(s = *++argv))) {
                rb_raise(rb_eRuntimeError, "missing argument for -E");
            }
            goto encoding;

          case 'U':
            set_internal_encoding_once(opt, "UTF-8", 0);
            ++s;
            goto reswitch;

          case 'K':
            if (*++s) {
                const char *enc_name = 0;
                switch (*s) {
                  case 'E': case 'e':
                    enc_name = "EUC-JP";
                    break;
                  case 'S': case 's':
                    enc_name = "Windows-31J";
                    break;
                  case 'U': case 'u':
                    enc_name = "UTF-8";
                    break;
                  case 'N': case 'n': case 'A': case 'a':
                    enc_name = "ASCII-8BIT";
                    break;
                }
                if (enc_name) {
                    opt->src.enc.name = rb_str_new2(enc_name);
                    if (!opt->ext.enc.name)
                        opt->ext.enc.name = opt->src.enc.name;
                }
                s++;
            }
            goto reswitch;

          case 'T':
            {
                size_t numlen;
                int v = 1;

                if (*++s) {
                    v = scan_oct(s, 2, &numlen);
                    if (numlen == 0)
                        v = 1;
                    s += numlen;
                }
                if (v > opt->safe_level) opt->safe_level = v;
            }
            goto reswitch;

          case 'I':
            forbid_setid("-I");
            if (*++s)
                ruby_incpush_expand(s);
            else if (argv[1]) {
                ruby_incpush_expand(argv[1]);
                argc--, argv++;
            }
            break;

          case '0':
            if (envopt) goto noenvopt;
            {
                size_t numlen;
                int v;
                char c;

                v = scan_oct(s, 4, &numlen);
                s += numlen;
                if (v > 0377)
                    rb_rs = Qnil;
                else if (v == 0 && numlen >= 2) {
                    rb_rs = rb_str_new2("\n\n");
                }
                else {
                    c = v & 0xff;
                    rb_rs = rb_str_new(&c, 1);
                }
            }
            goto reswitch;

          case '-':
            if (!s[1] || (s[1] == '\r' && !s[2])) {
                argc--, argv++;
                goto switch_end;
            }
            s++;

#       define is_option_end(c, allow_hyphen) \
            (!(c) || (allow_hyphen && (c) == '-') || (c) == '=')
#       define check_envopt(name, allow_envopt) \
            ((allow_envopt || !envopt) ? (void)0 : \
             rb_raise(rb_eRuntimeError, "invalid switch in RUBYOPT: --" name))
#       define need_argument(name, s) \
            ((*s++ ? !*s : (!--argc || !(s = *++argv))) ?               \
             rb_raise(rb_eRuntimeError, "missing argument for --" name) \
             : (void)0)
#       define is_option_with_arg(name, allow_hyphen, allow_envopt) \
            (strncmp(name, s, n = sizeof(name) - 1) == 0 && is_option_end(s[n], allow_hyphen) ? \
             (check_envopt(name, allow_envopt), s += n, need_argument(name, s), 1) : 0)

            if (strcmp("copyright", s) == 0) {
                if (envopt) goto noenvopt_long;
                opt->dump |= DUMP_BIT(copyright);
            }
            else if (strcmp("debug", s) == 0) {
                ruby_debug = Qtrue;
                ruby_verbose = Qtrue;
            }
            else if (is_option_with_arg("enable", Qtrue, Qtrue)) {
                ruby_each_words(s, enable_option, &opt->disable);
            }
            else if (is_option_with_arg("disable", Qtrue, Qtrue)) {
                ruby_each_words(s, disable_option, &opt->disable);
            }
            else if (is_option_with_arg("encoding", Qfalse, Qtrue)) {
                char *p;
              encoding:
                do {
#       define set_encoding_part(type) \
                    if (!(p = strchr(s, ':'))) { \
                        set_##type##_encoding_once(opt, s, 0); \
                        break; \
                    } \
                    else if (p > s) { \
                        set_##type##_encoding_once(opt, s, p-s); \
                    }
                    set_encoding_part(external);
                    if (!*(s = ++p)) break;
                    set_encoding_part(internal);
                    if (!*(s = ++p)) break;
#if ALLOW_DEFAULT_SOURCE_ENCODING
                    set_encoding_part(source);
                    if (!*(s = ++p)) break;
#endif
                    rb_raise(rb_eRuntimeError, "extra argument for %s: %s",
                             (arg[1] == '-' ? "--encoding" : "-E"), s);
#       undef set_encoding_part
                } while (0);
            }
            else if (is_option_with_arg("internal-encoding", Qfalse, Qtrue)) {
                set_internal_encoding_once(opt, s, 0);
            }
            else if (is_option_with_arg("external-encoding", Qfalse, Qtrue)) {
                set_external_encoding_once(opt, s, 0);
            }
#if ALLOW_DEFAULT_SOURCE_ENCODING
            else if (is_option_with_arg("source-encoding", Qfalse, Qtrue)) {
                set_source_encoding_once(opt, s, 0);
            }
#endif
            else if (strcmp("version", s) == 0) {
                if (envopt) goto noenvopt_long;
                opt->dump |= DUMP_BIT(version);
            }
            else if (strcmp("verbose", s) == 0) {
                opt->verbose = 1;
                ruby_verbose = Qtrue;
            }
            else if (strcmp("yydebug", s) == 0) {
                if (envopt) goto noenvopt_long;
                opt->dump |= DUMP_BIT(yydebug);
            }
            else if (is_option_with_arg("dump", Qfalse, Qfalse)) {
                ruby_each_words(s, dump_option, &opt->dump);
            }
            else if (strcmp("help", s) == 0) {
                if (envopt) goto noenvopt_long;
                opt->dump |= DUMP_BIT(usage);
                goto switch_end;
            }
            else {
                rb_raise(rb_eRuntimeError,
                         "invalid option --%s  (-h will show valid options)", s);
            }
            break;

          case '\r':
            if (!s[1])
                break;

          default:
            {
                if (ISPRINT(*s)) {
                    rb_raise(rb_eRuntimeError,
                        "invalid option -%c  (-h will show valid options)",
                        (int)(unsigned char)*s);
                }
                else {
                    rb_raise(rb_eRuntimeError,
                        "invalid option -\\x%02X  (-h will show valid options)",
                        (int)(unsigned char)*s);
                }
            }
            goto switch_end;

          noenvopt:
            /* "EIdvwWrKU" only */
            rb_raise(rb_eRuntimeError, "invalid switch in RUBYOPT: -%c", *s);
            break;

          noenvopt_long:
            rb_raise(rb_eRuntimeError, "invalid switch in RUBYOPT: --%s", s);
            break;

          case 0:
            break;
#       undef is_option_end
#       undef check_envopt
#       undef need_argument
#       undef is_option_with_arg
        }
    }

  switch_end:
    return argc0 - argc;
}

void Init_prelude(void);

static void
ruby_init_gems(int enable)
{
    if (enable) rb_define_module("Gem");
    Init_prelude();
    rb_const_remove(rb_cObject, rb_intern_const("TMP_RUBY_PREFIX"));
}

static int
opt_enc_index(VALUE enc_name)
{
    const char *s = RSTRING_PTR(enc_name);
    int i = rb_enc_find_index(s);

    if (i < 0) {
        rb_raise(rb_eRuntimeError, "unknown encoding name - %s", s);
    }
    else if (rb_enc_dummy_p(rb_enc_from_index(i))) {
        rb_raise(rb_eRuntimeError, "dummy encoding is not acceptable - %s ", s);
    }
    return i;
}

#define rb_progname (GET_VM()->progname)
VALUE rb_argv0;

static VALUE
false_value(void)
{
    return Qfalse;
}

static VALUE
true_value(void)
{
    return Qtrue;
}

#define rb_define_readonly_boolean(name, val) \
    rb_define_virtual_variable((name), (val) ? true_value : false_value, 0)

static VALUE
uscore_get(void)
{
    VALUE line;

    line = rb_lastline_get();
    if (TYPE(line) != T_STRING) {
        rb_raise(rb_eTypeError, "$_ value need to be String (%s given)",
                 NIL_P(line) ? "nil" : rb_obj_classname(line));
    }
    return line;
}

/*
 *  call-seq:
 *     sub(pattern, replacement)   -> $_
 *     sub(pattern) { block }      -> $_
 *
 *  Equivalent to <code>$_.sub(<i>args</i>)</code>, except that
 *  <code>$_</code> will be updated if substitution occurs.
 *  Available only when -p/-n command line option specified.
 */

static VALUE
rb_f_sub(argc, argv)
    int argc;
    VALUE *argv;
{
    VALUE str = rb_funcall3(uscore_get(), rb_intern("sub"), argc, argv);
    rb_lastline_set(str);
    return str;
}

/*
 *  call-seq:
 *     gsub(pattern, replacement)    -> string
 *     gsub(pattern) {|...| block }  -> string
 *
 *  Equivalent to <code>$_.gsub...</code>, except that <code>$_</code>
 *  receives the modified result.
 *  Available only when -p/-n command line option specified.
 *
 */

static VALUE
rb_f_gsub(argc, argv)
    int argc;
    VALUE *argv;
{
    VALUE str = rb_funcall3(uscore_get(), rb_intern("gsub"), argc, argv);
    rb_lastline_set(str);
    return str;
}

/*
 *  call-seq:
 *     chop   -> string
 *
 *  Equivalent to <code>($_.dup).chop!</code>, except <code>nil</code>
 *  is never returned. See <code>String#chop!</code>.
 *  Available only when -p/-n command line option specified.
 *
 */

static VALUE
rb_f_chop(void)
{
    VALUE str = rb_funcall3(uscore_get(), rb_intern("chop"), 0, 0);
    rb_lastline_set(str);
    return str;
}


/*
 *  call-seq:
 *     chomp            -> $_
 *     chomp(string)    -> $_
 *
 *  Equivalent to <code>$_ = $_.chomp(<em>string</em>)</code>. See
 *  <code>String#chomp</code>.
 *  Available only when -p/-n command line option specified.
 *
 */

static VALUE
rb_f_chomp(argc, argv)
    int argc;
    VALUE *argv;
{
    VALUE str = rb_funcall3(uscore_get(), rb_intern("chomp"), argc, argv);
    rb_lastline_set(str);
    return str;
}

void rb_stdio_set_default_encoding(void);
VALUE rb_parser_dump_tree(NODE *node, int comment);

static VALUE
process_options(int argc, char **argv, struct cmdline_options *opt)
{
    NODE *tree = 0;
    VALUE parser;
    VALUE iseq;
    rb_encoding *enc, *lenc;
    const char *s;
    char fbuf[MAXPATHLEN];
    int i = (int)proc_options(argc, argv, opt, 0);
    rb_thread_t *th = GET_THREAD();
    rb_env_t *env = 0;

    argc -= i;
    argv += i;

    if (opt->dump & DUMP_BIT(usage)) {
        usage(origarg.argv[0]);
        return Qtrue;
    }

    if (!(opt->disable & DISABLE_BIT(rubyopt)) &&
        opt->safe_level == 0 && (s = getenv("RUBYOPT"))) {
        VALUE src_enc_name = opt->src.enc.name;
        VALUE ext_enc_name = opt->ext.enc.name;
        VALUE int_enc_name = opt->intern.enc.name;

        opt->src.enc.name = opt->ext.enc.name = opt->intern.enc.name = 0;
        moreswitches(s, opt, 1);
        if (src_enc_name)
            opt->src.enc.name = src_enc_name;
        if (ext_enc_name)
            opt->ext.enc.name = ext_enc_name;
        if (int_enc_name)
            opt->intern.enc.name = int_enc_name;
    }

    if (opt->dump & DUMP_BIT(version)) {
        ruby_show_version();
        return Qtrue;
    }
    if (opt->dump & DUMP_BIT(copyright)) {
        ruby_show_copyright();
    }

    if (opt->safe_level >= 4) {
        OBJ_TAINT(rb_argv);
        OBJ_TAINT(GET_VM()->load_path);
    }

    if (!opt->e_script) {
        if (argc == 0) {        /* no more args */
            if (opt->verbose)
                return Qtrue;
            opt->script = "-";
        }
        else {
            opt->script = argv[0];
            if (opt->script[0] == '\0') {
                opt->script = "-";
            }
            else if (opt->do_search) {
                char *path = getenv("RUBYPATH");

                opt->script = 0;
                if (path) {
                    opt->script = dln_find_file_r(argv[0], path, fbuf, sizeof(fbuf));
                }
                if (!opt->script) {
                    opt->script = dln_find_file_r(argv[0], getenv(PATH_ENV), fbuf, sizeof(fbuf));
                }
                if (!opt->script)
                    opt->script = argv[0];
            }
            argc--;
            argv++;
        }
    }

    opt->script_name = rb_str_new_cstr(opt->script);
    opt->script = RSTRING_PTR(opt->script_name);
#if defined DOSISH || defined __CYGWIN__
    translit_char(RSTRING_PTR(opt->script_name), '\\', '/');
#endif
    rb_obj_freeze(opt->script_name);

    ruby_init_loadpath_safe(opt->safe_level);
    rb_enc_find_index("encdb");
    lenc = rb_locale_encoding();
    rb_enc_associate(rb_progname, lenc);
    parser = rb_parser_new();
    if (opt->dump & DUMP_BIT(yydebug)) {
        rb_parser_set_yydebug(parser, Qtrue);
    }
    if (opt->ext.enc.name != 0) {
        opt->ext.enc.index = opt_enc_index(opt->ext.enc.name);
    }
    if (opt->intern.enc.name != 0) {
        opt->intern.enc.index = opt_enc_index(opt->intern.enc.name);
    }
    if (opt->src.enc.name != 0) {
        opt->src.enc.index = opt_enc_index(opt->src.enc.name);
        src_encoding_index = opt->src.enc.index;
    }
    if (opt->ext.enc.index >= 0) {
        enc = rb_enc_from_index(opt->ext.enc.index);
    }
    else {
        enc = lenc;
    }
    rb_enc_set_default_external(rb_enc_from_encoding(enc));
    if (opt->intern.enc.index >= 0) {
        enc = rb_enc_from_index(opt->intern.enc.index);
        rb_enc_set_default_internal(rb_enc_from_encoding(enc));
        opt->intern.enc.index = -1;
    }
    rb_enc_associate(opt->script_name, lenc);
    {
        long i;
        VALUE load_path = GET_VM()->load_path;
        for (i = 0; i < RARRAY_LEN(load_path); ++i) {
            rb_enc_associate(RARRAY_PTR(load_path)[i], lenc);
        }
    }
    ruby_init_gems(!(opt->disable & DISABLE_BIT(gems)));
    ruby_set_argv(argc, argv);
    process_sflag(&opt->sflag);

    {
        /* set eval context */
        VALUE toplevel_binding = rb_const_get(rb_cObject, rb_intern("TOPLEVEL_BINDING"));
        rb_binding_t *bind;

        GetBindingPtr(toplevel_binding, bind);
        GetEnvPtr(bind->env, env);
    }

#define PREPARE_PARSE_MAIN(expr) do { \
    th->parse_in_eval--; \
    th->base_block = &env->block; \
    expr; \
    th->parse_in_eval++; \
    th->base_block = 0; \
} while (0)

    if (opt->e_script) {
        VALUE progname = rb_progname;
        rb_encoding *eenc;
        if (opt->src.enc.index >= 0) {
            eenc = rb_enc_from_index(opt->src.enc.index);
        }
        else {
            eenc = lenc;
        }
        rb_enc_associate(opt->e_script, eenc);
        rb_vm_set_progname(rb_progname = opt->script_name);
        require_libraries(&opt->req_list);
        rb_vm_set_progname(rb_progname = progname);

        PREPARE_PARSE_MAIN({
            tree = rb_parser_compile_string(parser, opt->script, opt->e_script, 1);
        });
    }
    else {
        if (opt->script[0] == '-' && !opt->script[1]) {
            forbid_setid("program input from stdin");
        }

        PREPARE_PARSE_MAIN({
            tree = load_file(parser, opt->script, 1, opt);
        });
    }
    rb_progname = opt->script_name;
    rb_vm_set_progname(rb_progname);
    if (opt->dump & DUMP_BIT(yydebug)) return Qtrue;

    if (opt->ext.enc.index >= 0) {
        enc = rb_enc_from_index(opt->ext.enc.index);
    }
    else {
        enc = lenc;
    }
    rb_enc_set_default_external(rb_enc_from_encoding(enc));
    if (opt->intern.enc.index >= 0) {
        /* Set in the shebang line */
        enc = rb_enc_from_index(opt->intern.enc.index);
        rb_enc_set_default_internal(rb_enc_from_encoding(enc));
    }
    else if (!rb_default_internal_encoding())
        /* Freeze default_internal */
        rb_enc_set_default_internal(Qnil);
    rb_stdio_set_default_encoding();

    if (!tree) return Qfalse;

    process_sflag(&opt->sflag);
    opt->xflag = 0;

    if (opt->safe_level >= 4) {
        FL_UNSET(rb_argv, FL_TAINT);
        FL_UNSET(GET_VM()->load_path, FL_TAINT);
    }

    if (opt->dump & DUMP_BIT(syntax)) {
        printf("Syntax OK\n");
        return Qtrue;
    }

    if (opt->do_print) {
        PREPARE_PARSE_MAIN({
            tree = rb_parser_append_print(parser, tree);
        });
    }
    if (opt->do_loop) {
        PREPARE_PARSE_MAIN({
            tree = rb_parser_while_loop(parser, tree, opt->do_line, opt->do_split);
        });
        rb_define_global_function("sub", rb_f_sub, -1);
        rb_define_global_function("gsub", rb_f_gsub, -1);
        rb_define_global_function("chop", rb_f_chop, 0);
        rb_define_global_function("chomp", rb_f_chomp, -1);
    }

    if (opt->dump & DUMP_BIT(parsetree) || opt->dump & DUMP_BIT(parsetree_with_comment)) {
        rb_io_write(rb_stdout, rb_parser_dump_tree(tree, opt->dump & DUMP_BIT(parsetree_with_comment)));
        rb_io_flush(rb_stdout);
        return Qtrue;
    }

    PREPARE_PARSE_MAIN({
        VALUE path = Qnil;
        if (!opt->e_script && strcmp(opt->script, "-")) path = opt->script_name;
        iseq = rb_iseq_new_main(tree, opt->script_name, path);
    });

    if (opt->dump & DUMP_BIT(insns)) {
        rb_io_write(rb_stdout, rb_iseq_disasm(iseq));
        rb_io_flush(rb_stdout);
        return Qtrue;
    }

    rb_define_readonly_boolean("$-p", opt->do_print);
    rb_define_readonly_boolean("$-l", opt->do_line);
    rb_define_readonly_boolean("$-a", opt->do_split);

    rb_set_safe_level(opt->safe_level);

    return iseq;
}

struct load_file_arg {
    VALUE parser;
    const char *fname;
    int script;
    struct cmdline_options *opt;
};

static VALUE
load_file_internal(VALUE arg)
{
    extern VALUE rb_stdin;
    struct load_file_arg *argp = (struct load_file_arg *)arg;
    VALUE parser = argp->parser;
    const char *fname = argp->fname;
    int script = argp->script;
    struct cmdline_options *opt = argp->opt;
    VALUE f;
    int line_start = 1;
    NODE *tree = 0;
    rb_encoding *enc;
    ID set_encoding;

    if (!fname)
        rb_load_fail(fname);
    if (strcmp(fname, "-") == 0) {
        f = rb_stdin;
    }
    else {
        int fd, mode = O_RDONLY;
#if defined DOSISH || defined __CYGWIN__
        {
            const char *ext = strrchr(fname, '.');
            if (ext && STRCASECMP(ext, ".exe") == 0)
                mode |= O_BINARY;
        }
#endif
        if ((fd = open(fname, mode)) < 0) {
            rb_load_fail(fname);
        }

        f = rb_io_fdopen(fd, mode, fname);
    }

    CONST_ID(set_encoding, "set_encoding");
    if (script) {
        VALUE c = 1;            /* something not nil */
        VALUE line;
        char *p;
        int no_src_enc = !opt->src.enc.name;
        int no_ext_enc = !opt->ext.enc.name;
        int no_int_enc = !opt->intern.enc.name;

        enc = rb_ascii8bit_encoding();
        rb_funcall(f, set_encoding, 1, rb_enc_from_encoding(enc));

        if (opt->xflag) {
            line_start--;
          search_shebang:
            forbid_setid("-x");
            opt->xflag = FALSE;
            while (!NIL_P(line = rb_io_gets(f))) {
                line_start++;
                if (RSTRING_LEN(line) > 2
                    && RSTRING_PTR(line)[0] == '#'
                    && RSTRING_PTR(line)[1] == '!') {
                    if ((p = strstr(RSTRING_PTR(line), "ruby")) != 0) {
                        goto start_read;
                    }
                }
            }
            rb_raise(rb_eLoadError, "no Ruby script found in input");
        }

        c = rb_io_getbyte(f);
        if (c == INT2FIX('#')) {
            c = rb_io_getbyte(f);
            if (c == INT2FIX('!')) {
                line = rb_io_gets(f);
                if (NIL_P(line))
                    return 0;

                if ((p = strstr(RSTRING_PTR(line), "ruby")) == 0) {
                    /* not ruby script, assume -x flag */
                    goto search_shebang;
                }

              start_read:
                p += 4;
                RSTRING_PTR(line)[RSTRING_LEN(line) - 1] = '\0';
                if (RSTRING_PTR(line)[RSTRING_LEN(line) - 2] == '\r')
                    RSTRING_PTR(line)[RSTRING_LEN(line) - 2] = '\0';
                if ((p = strstr(p, " -")) != 0) {
                    moreswitches(p + 1, opt, 0);
                }

                /* push back shebang for pragma may exist in next line */
                rb_io_ungetbyte(f, rb_str_new2("!\n"));
            }
            else if (!NIL_P(c)) {
                rb_io_ungetbyte(f, c);
            }
            rb_io_ungetbyte(f, INT2FIX('#'));
            if (no_src_enc && opt->src.enc.name) {
                opt->src.enc.index = opt_enc_index(opt->src.enc.name);
                src_encoding_index = opt->src.enc.index;
            }
            if (no_ext_enc && opt->ext.enc.name) {
                opt->ext.enc.index = opt_enc_index(opt->ext.enc.name);
            }
            if (no_int_enc && opt->intern.enc.name) {
                opt->intern.enc.index = opt_enc_index(opt->intern.enc.name);
            }
        }
        else if (!NIL_P(c)) {
            rb_io_ungetbyte(f, c);
        }
        else {
            if (f != rb_stdin) rb_io_close(f);
            f = Qnil;
        }
        rb_vm_set_progname(rb_progname = opt->script_name);
        require_libraries(&opt->req_list);      /* Why here? unnatural */
    }
    if (opt->src.enc.index >= 0) {
        enc = rb_enc_from_index(opt->src.enc.index);
    }
    else if (f == rb_stdin) {
        enc = rb_locale_encoding();
    }
    else {
        enc = rb_usascii_encoding();
    }
    if (NIL_P(f)) {
        f = rb_str_new(0, 0);
        rb_enc_associate(f, enc);
        return (VALUE)rb_parser_compile_string(parser, fname, f, line_start);
    }
    rb_funcall(f, set_encoding, 2, rb_enc_from_encoding(enc), rb_str_new_cstr("-"));
    tree = rb_parser_compile_file(parser, fname, f, line_start);
    rb_funcall(f, set_encoding, 1, rb_parser_encoding(parser));
    if (script && tree && rb_parser_end_seen_p(parser)) {
        rb_define_global_const("DATA", f);
    }
    else if (f != rb_stdin) {
        rb_io_close(f);
    }
    return (VALUE)tree;
}

static VALUE
restore_lineno(VALUE lineno)
{
    return rb_gv_set("$.", lineno);
}

static NODE *
load_file(VALUE parser, const char *fname, int script, struct cmdline_options *opt)
{
    struct load_file_arg arg;
    arg.parser = parser;
    arg.fname = fname;
    arg.script = script;
    arg.opt = opt;
    return (NODE *)rb_ensure(load_file_internal, (VALUE)&arg, restore_lineno, rb_gv_get("$."));
}

void *
rb_load_file(const char *fname)
{
    struct cmdline_options opt;

    return load_file(rb_parser_new(), fname, 0, cmdline_options_init(&opt));
}

#if !defined(PSTAT_SETCMD) && !defined(HAVE_SETPROCTITLE)
#if !defined(_WIN32)
#define USE_ENVSPACE_FOR_ARG0
#endif

#ifdef USE_ENVSPACE_FOR_ARG0
extern char **environ;
#endif

static size_t
get_arglen(int argc, char **argv)
{
    char *s = argv[0];
    int i;

    if (!argc) return 0;
    s += strlen(s);
    /* See if all the arguments are contiguous in memory */
    for (i = 1; i < argc; i++) {
        if (argv[i] == s + 1) {
            s++;
            s += strlen(s);     /* this one is ok too */
        }
        else {
            break;
        }
    }
#if defined(USE_ENVSPACE_FOR_ARG0)
    if (environ && (s+1 == environ[0])) {
        s++;
        s += strlen(s);
        for (i = 1; environ[i]; i++) {
            if (environ[i] == s + 1) {
                s++;
                s += strlen(s); /* this one is ok too */
            }
        }
# if defined(HAVE_SETENV) && defined(HAVE_UNSETENV)
        {
            char *t = malloc(s - environ[0] + 1);
            for (i = 0; environ[i]; i++) {
                size_t len = strlen(environ[i]) + 1;
                memcpy(t, environ[i], len);
                environ[i] = t;
                t += len;
            }
        }
# else
        ruby_setenv("", NULL); /* duplicate environ vars */
# endif
    }
#endif
    return s - argv[0];
}
#endif

static void
set_arg0(VALUE val, ID id)
{
    char *s;
    long i;

    if (origarg.argv == 0)
        rb_raise(rb_eRuntimeError, "$0 not initialized");
    StringValue(val);
    s = RSTRING_PTR(val);
    i = RSTRING_LEN(val);
#if defined(PSTAT_SETCMD)
    if (i > PST_CLEN) {
        union pstun un;
        char buf[PST_CLEN + 1]; /* PST_CLEN is 64 (HP-UX 11.23) */
        strlcpy(buf, s, sizeof(buf));
        un.pst_command = buf;
        pstat(PSTAT_SETCMD, un, PST_CLEN, 0, 0);
    }
    else {
        union pstun un;
        un.pst_command = s;
        pstat(PSTAT_SETCMD, un, i, 0, 0);
    }
#elif defined(HAVE_SETPROCTITLE)
    setproctitle("%.*s", (int)i, s);
#else

    if ((size_t)i > origarg.len - origarg.argc) {
        i = (long)(origarg.len - origarg.argc);
    }

    memcpy(origarg.argv[0], s, i);

    {
        int j;
        char *t = origarg.argv[0] + i;
        *t = '\0';

        if ((size_t)(i + 1) < origarg.len) {
            memset(t + 1, '\0', origarg.len - i - 1);
        }
        for (j = 1; j < origarg.argc; j++) {
            origarg.argv[j] = t;
        }
    }
#endif
    rb_progname = rb_obj_freeze(rb_external_str_new(s, i));
}

void
ruby_script(const char *name)
{
    if (name) {
        rb_progname = rb_obj_freeze(rb_external_str_new(name, strlen(name)));
        rb_vm_set_progname(rb_progname);
    }
}

static void
init_ids(struct cmdline_options *opt)
{
    rb_uid_t uid = getuid();
    rb_uid_t euid = geteuid();
    rb_gid_t gid = getgid();
    rb_gid_t egid = getegid();

    if (uid != euid) opt->setids |= 1;
    if (egid != gid) opt->setids |= 2;
    if (uid && opt->setids) {
        if (opt->safe_level < 1) opt->safe_level = 1;
    }
}

#undef forbid_setid
static void
forbid_setid(const char *s, struct cmdline_options *opt)
{
    if (opt->setids & 1)
        rb_raise(rb_eSecurityError, "no %s allowed while running setuid", s);
    if (opt->setids & 2)
        rb_raise(rb_eSecurityError, "no %s allowed while running setgid", s);
    if (opt->safe_level > 0)
        rb_raise(rb_eSecurityError, "no %s allowed in tainted mode", s);
}

static void
verbose_setter(VALUE val, ID id, void *data)
{
    VALUE *variable = data;
    *variable = RTEST(val) ? Qtrue : val;
}

static VALUE
opt_W_getter(ID id, void *data)
{
    VALUE *variable = data;
    switch (*variable) {
      case Qnil:
        return INT2FIX(0);
      case Qfalse:
        return INT2FIX(1);
      case Qtrue:
        return INT2FIX(2);
    }
    return Qnil;                /* not reached */
}

void
ruby_prog_init(void)
{
    rb_define_hooked_variable("$VERBOSE", &ruby_verbose, 0, verbose_setter);
    rb_define_hooked_variable("$-v", &ruby_verbose, 0, verbose_setter);
    rb_define_hooked_variable("$-w", &ruby_verbose, 0, verbose_setter);
    rb_define_hooked_variable("$-W", &ruby_verbose, opt_W_getter, rb_gvar_readonly_setter);
    rb_define_variable("$DEBUG", &ruby_debug);
    rb_define_variable("$-d", &ruby_debug);

    rb_define_hooked_variable("$0", &rb_progname, 0, set_arg0);
    rb_define_hooked_variable("$PROGRAM_NAME", &rb_progname, 0, set_arg0);

    rb_define_global_const("ARGV", rb_argv);
}

void
ruby_set_argv(int argc, char **argv)
{
    int i;
    VALUE av = rb_argv;

#if defined(USE_DLN_A_OUT)
    if (origarg.argv)
        dln_argv0 = origarg.argv[0];
    else
        dln_argv0 = argv[0];
#endif
    rb_ary_clear(av);
    for (i = 0; i < argc; i++) {
        VALUE arg = rb_external_str_new(argv[i], strlen(argv[i]));

        OBJ_FREEZE(arg);
        rb_ary_push(av, arg);
    }
}

void *
ruby_process_options(int argc, char **argv)
{
    struct cmdline_options opt;
    VALUE iseq;

    ruby_script(argv[0]);  /* for the time being */
    rb_argv0 = rb_str_new4(rb_progname);
    rb_gc_register_mark_object(rb_argv0);
    iseq = process_options(argc, argv, cmdline_options_init(&opt));
    return (void*)(struct RData*)iseq;
}

void
ruby_sysinit(int *argc, char ***argv)
{
#if defined(_WIN32)
    void rb_w32_sysinit(int *argc, char ***argv);
    rb_w32_sysinit(argc, argv);
#endif
    origarg.argc = *argc;
    origarg.argv = *argv;
#if !defined(PSTAT_SETCMD) && !defined(HAVE_SETPROCTITLE)
    origarg.len = get_arglen(origarg.argc, origarg.argv);
#endif
#if defined(USE_DLN_A_OUT)
    dln_argv0 = origarg.argv[0];
#endif
}

---