ruby.c

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

  ruby.c -

  $Author: tmm1 $
  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 "internal.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

#ifndef DISABLE_RUBYGEMS
# define DISABLE_RUBYGEMS 0
#endif
#if DISABLE_RUBYGEMS
#define DEFAULT_RUBYGEMS_ENABLED "disabled"
#else
#define DEFAULT_RUBYGEMS_ENABLED "enabled"
#endif

#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_version_v,
    dump_copyright,
    dump_usage,
    dump_help,
    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;
#if DISABLE_RUBYGEMS
    opt->disable |= DISABLE_BIT(gems);
#endif
    return opt;
}

static NODE *load_file(VALUE, VALUE, 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;
} origarg;

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

    struct message {
        const char *str;
        unsigned short namelen, secondlen;
    };
#define M(shortopt, longopt, desc) { \
    shortopt " " longopt " " desc, \
    (unsigned short)sizeof(shortopt), \
    (unsigned short)sizeof(longopt), \
}
    static const struct message usage_msg[] = {
        M("-0[octal]",     "",                     "specify record separator (\\0, if no argument)"),
        M("-a",            "",                     "autosplit mode with -n or -p (splits $_ into $F)"),
        M("-c",            "",                     "check syntax only"),
        M("-Cdirectory",   "",                     "cd to directory before executing your script"),
        M("-d",            ", --debug",            "set debugging flags (set $DEBUG to true)"),
        M("-e 'command'",  "",                     "one line of script. Several -e's allowed. Omit [programfile]"),
        M("-Eex[:in]",     ", --encoding=ex[:in]", "specify the default external and internal character encodings"),
        M("-Fpattern",     "",                     "split() pattern for autosplit (-a)"),
        M("-i[extension]", "",                     "edit ARGV files in place (make backup if extension supplied)"),
        M("-Idirectory",   "",                     "specify $LOAD_PATH directory (may be used more than once)"),
        M("-l",            "",                     "enable line ending processing"),
        M("-n",            "",                     "assume 'while gets(); ... end' loop around your script"),
        M("-p",            "",                     "assume loop like -n but print line also like sed"),
        M("-rlibrary",     "",                     "require the library before executing your script"),
        M("-s",            "",                     "enable some switch parsing for switches after script name"),
        M("-S",            "",                     "look for the script using PATH environment variable"),
        M("-T[level=1]",   "",                     "turn on tainting checks"),
        M("-v",            ", --verbose",          "print version number, then turn on verbose mode"),
        M("-w",            "",                     "turn warnings on for your script"),
        M("-W[level=2]",   "",                     "set warning level; 0=silence, 1=medium, 2=verbose"),
        M("-x[directory]", "",                     "strip off text before #!ruby line and perhaps cd to directory"),
        M("-h",            "",                     "show this message, --help for more info"),
    };
    static const struct message help_msg[] = {
        M("--copyright",                   "", "print the copyright"),
        M("--enable=feature[,...]",        ", --disable=feature[,...]",
          "enable or disable features"),
        M("--external-encoding=encoding",  ", --internal-encoding=encoding",
          "specify the default external or internal character encoding"),
        M("--version",                     "", "print the version"),
        M("--help",                        "", "show this message, -h for short message"),
    };
    static const struct message features[] = {
        M("gems",    "",        "rubygems (default: "DEFAULT_RUBYGEMS_ENABLED")"),
        M("rubyopt", "",        "RUBYOPT environment variable (default: enabled)"),
    };
    int i, w = 16, num = numberof(usage_msg) - (help ? 1 : 0);
#define SHOW(m) do { \
        int wrap = help && (m).namelen + (m).secondlen - 2 > w; \
        printf("  %.*s%-*.*s%-*s%s\n", (m).namelen-1, (m).str, \
               (wrap ? 0 : w - (m).namelen + 1), \
               (help ? (m).secondlen-1 : 0), (m).str + (m).namelen, \
               (wrap ? w + 3 : 0), (wrap ? "\n" : ""), \
               (m).str + (m).namelen + (m).secondlen); \
    } while (0)

    printf("Usage: %s [switches] [--] [programfile] [arguments]\n", name);
    for (i = 0; i < num; ++i)
        SHOW(usage_msg[i]);

    if (!help) return;

    for (i = 0; i < numberof(help_msg); ++i)
        SHOW(help_msg[i]);
    puts("Features:");
    for (i = 0; i < numberof(features); ++i)
        SHOW(features[i]);
}

#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);
            }
        }
#ifdef HAVE_CYGWIN_CONV_PATH
#define CONV_TO_POSIX_PATH(p, lib) \
        cygwin_conv_path(CCP_WIN_A_TO_POSIX|CCP_RELATIVE, (p), (lib), sizeof(lib))
#else
#define CONV_TO_POSIX_PATH(p, lib) \
        cygwin_conv_to_posix_path((p), (lib))
#endif
        if (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 HAVE_CYGWIN_CONV_PATH
#   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)) {
        char fbuf[MAXPATHLEN];
        char *f = dln_find_file_r(dli.dli_fname, getenv(PATH_ENV), fbuf, sizeof(fbuf));
        VALUE fname = rb_str_new_cstr(f ? f : dli.dli_fname);
        rb_str_freeze(fname);
        sopath = rb_realpath_internal(Qnil, fname, 1);
    }
    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) {
        static const char bindir[] = "/bin";
#ifdef LIBDIR_BASENAME
        static const char libdir[] = "/"LIBDIR_BASENAME;
#else
        static const char libdir[] = "/lib";
#endif
        const ptrdiff_t bindir_len = (ptrdiff_t)sizeof(bindir) - 1;
        const ptrdiff_t libdir_len = (ptrdiff_t)sizeof(libdir) - 1;

#ifdef ENABLE_MULTIARCH
        char *p2 = NULL;

      multiarch:
#endif
        if (p - libpath >= bindir_len && !STRNCASECMP(p - bindir_len, bindir, bindir_len)) {
            p -= bindir_len;
        }
        else if (p - libpath >= libdir_len && !strncmp(p - libdir_len, libdir, libdir_len)) {
            p -= libdir_len;
        }
#ifdef ENABLE_MULTIARCH
        else if (p2) {
            p = p2;
        }
        else {
            p2 = p;
            p = rb_enc_path_last_separator(libpath, p, rb_ascii8bit_encoding());
            if (p) goto multiarch;
            p = p2;
        }
#endif
        *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_resize(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
    extern const char ruby_exec_prefix[];
    const size_t exec_prefix_len = strlen(ruby_exec_prefix);
#define RUBY_RELATIVE(path, len) rubylib_mangled_path((path), (len))
#define PREFIX_PATH() RUBY_RELATIVE(ruby_exec_prefix, exec_prefix_len)
#endif
    load_path = GET_VM()->load_path;

    if (safe_level == 0) {
#ifdef MANGLED_PATH
        rubylib_mangled_path("", 0);
#endif
        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;
    VALUE feature;

    if (!list) {
        *req_list = list = rb_ary_new();
        RBASIC_CLEAR_CLASS(list);
    }
    feature = rb_str_new2(mod);
    RBASIC_CLEAR_CLASS(feature);
    rb_ary_push(list, feature);
}

static void
require_libraries(VALUE *req_list)
{
    VALUE list = *req_list;
    VALUE self = rb_vm_top_self();
    ID require;
    rb_thread_t *th = GET_THREAD();
    rb_encoding *extenc = rb_default_external_encoding();
    int prev_parse_in_eval = th->parse_in_eval;
    th->parse_in_eval = 0;

    CONST_ID(require, "require");
    while (list && RARRAY_LEN(list) > 0) {
        VALUE feature = rb_ary_shift(list);
        rb_enc_associate(feature, extenc);
        RBASIC_SET_CLASS_RAW(feature, rb_cString);
        OBJ_FREEZE(feature);
        rb_funcall2(self, require, 1, &feature);
    }
    *req_list = 0;

    th->parse_in_eval = prev_parse_in_eval;
}

static rb_env_t*
toplevel_context(VALUE toplevel_binding)
{
    rb_env_t *env;
    rb_binding_t *bind;

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

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

        n = RARRAY_LEN(argv);
        args = RARRAY_CONST_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;
    }
}

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(help);
    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 %"PRIsVALUE, type, *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 || 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;
            }
            opt->dump |= DUMP_BIT(version_v);
            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, needs_arg) \
            ((*(s)++ ? !*(s) : (!--argc || !((s) = *++argv))) && (needs_arg) ? \
             rb_raise(rb_eRuntimeError, "missing argument for --" name) \
             : (void)0)
#       define is_option_with_arg(name, allow_hyphen, allow_envopt)     \
            is_option_with_optarg(name, allow_hyphen, allow_envopt, Qtrue)
#       define is_option_with_optarg(name, allow_hyphen, allow_envopt, needs_arg) \
            (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, needs_arg), 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 defined ALLOW_DEFAULT_SOURCE_ENCODING && 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 defined ALLOW_DEFAULT_SOURCE_ENCODING && 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(help);
                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
#       undef is_option_with_optarg
        }
    }

  switch_end:
    return argc0 - argc;
}

static void
ruby_init_prelude(void)
{
    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)
#define rb_orig_progname (GET_VM()->orig_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 (!RB_TYPE_P(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(int argc, VALUE *argv)
{
    VALUE str = rb_funcall_passing_block(uscore_get(), rb_intern("sub"), argc, argv);
    rb_lastline_set(str);
    return str;
}

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

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

/*
 *  call-seq:
 *     chop   -> $_
 *
 *  Equivalent to <code>($_.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_funcall_passing_block(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(int argc, VALUE *argv)
{
    VALUE str = rb_funcall_passing_block(uscore_get(), rb_intern("chomp"), argc, argv);
    rb_lastline_set(str);
    return str;
}

/* blank function in dmyext.c or generated by enc/make_encmake.rb */
extern void Init_enc(void);

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();
    VALUE toplevel_binding = Qundef;

    argc -= i;
    argv += i;

    if (opt->dump & (DUMP_BIT(usage)|DUMP_BIT(help))) {
        usage(origarg.argv[0], (opt->dump & DUMP_BIT(help)));
        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->src.enc.name)
        rb_warning("-K is specified; it is for 1.8 compatibility and may cause odd behavior");

    if (opt->dump & (DUMP_BIT(version) | DUMP_BIT(version_v))) {
        ruby_show_version();
        if (opt->dump & DUMP_BIT(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 || 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

    ruby_gc_set_params(opt->safe_level);
    ruby_init_loadpath_safe(opt->safe_level);
    Init_enc();
    rb_enc_find_index("encdb");
    lenc = rb_locale_encoding();
    rb_enc_associate(rb_progname, lenc);
    rb_obj_freeze(rb_progname);
    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);
    rb_obj_freeze(opt->script_name);
    {
        long i;
        VALUE load_path = GET_VM()->load_path;
        for (i = 0; i < RARRAY_LEN(load_path); ++i) {
            RARRAY_ASET(load_path, i,
                        rb_enc_associate(rb_str_dup(RARRAY_AREF(load_path, i)), lenc));
        }
    }
    Init_ext();         /* load statically linked extensions before rubygems */
    if (!(opt->disable & DISABLE_BIT(gems))) {
        rb_define_module("Gem");
    }
    ruby_init_prelude();
    ruby_set_argv(argc, argv);
    process_sflag(&opt->sflag);

    toplevel_binding = rb_const_get(rb_cObject, rb_intern("TOPLEVEL_BINDING"));

#define PREPARE_PARSE_MAIN(expr) do { \
    rb_env_t *env = toplevel_context(toplevel_binding); \
    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);
        ruby_set_script_name(opt->script_name);
        require_libraries(&opt->req_list);
        ruby_set_script_name(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_name, 1, opt);
        });
    }
    ruby_set_script_name(opt->script_name);
    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 = rb_realpath_internal(Qnil, opt->script_name, 1);
        }
        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;
    VALUE 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;
    VALUE orig_fname = argp->fname;
    VALUE fname_v = rb_str_encode_ospath(orig_fname);
    const char *fname = StringValueCStr(fname_v);
    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;
    int xflag = 0;

    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;
                xflag = 1;
            }
        }
#endif
        if ((fd = rb_cloexec_open(fname, mode, 0)) < 0) {
            rb_load_fail(fname_v, strerror(errno));
        }
        rb_update_max_fd(fd);
#if !defined DOSISH && !defined __CYGWIN__
        {
            struct stat st;
            if (fstat(fd, &st) != 0)
                rb_load_fail(fname_v, strerror(errno));
            if (S_ISDIR(st.st_mode)) {
                errno = EISDIR;
                rb_load_fail(fname_v, strerror(EISDIR));
            }
        }
#endif
        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 (xflag || 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_loaderror("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;
        }
        ruby_set_script_name(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_utf8_encoding();
    }
    if (NIL_P(f)) {
        f = rb_str_new(0, 0);
        rb_enc_associate(f, enc);
        return (VALUE)rb_parser_compile_string_path(parser, orig_fname, f, line_start);
    }
    rb_funcall(f, set_encoding, 2, rb_enc_from_encoding(enc), rb_str_new_cstr("-"));
    tree = rb_parser_compile_file_path(parser, orig_fname, f, line_start);
    rb_funcall(f, set_encoding, 1, rb_parser_encoding(parser));
    if (script && tree && rb_parser_end_seen_p(parser)) {
        /*
         * DATA is a File that contains the data section of the executed file.
         * To create a data section use <tt>__END__</tt>:
         *
         *   $ cat t.rb
         *   puts DATA.gets
         *   __END__
         *   hello world!
         *
         *   $ ruby t.rb
         *   hello world!
         */
        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, VALUE 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)
{
    VALUE fname_v = rb_str_new_cstr(fname);
    return rb_load_file_str(fname_v);
}

void *
rb_load_file_str(VALUE fname_v)
{
    struct cmdline_options opt;

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

/*
 *  call-seq:
 *     Process.argv0  -> frozen_string
 *
 *  Returns the name of the script being executed.  The value is not
 *  affected by assigning a new value to $0.
 *
 *  This method first appeared in Ruby 2.1 to serve as a global
 *  variable free means to get the script name.
 */

static VALUE
proc_argv0(VALUE process)
{
    return rb_orig_progname;
}

/*
 *  call-seq:
 *     Process.setproctitle(string)  -> string
 *
 *  Sets the process title that appears on the ps(1) command.  Not
 *  necessarily effective on all platforms.  No exception will be
 *  raised regardless of the result, nor will NotImplementedError be
 *  raised even if the platform does not support the feature.
 *
 *  Calling this method does not affect the value of $0.
 *
 *     Process.setproctitle('myapp: worker #%d' % worker_id)
 *
 *  This method first appeared in Ruby 2.1 to serve as a global
 *  variable free means to change the process title.
 */

static VALUE
proc_setproctitle(VALUE process, VALUE title)
{
    StringValue(title);

    setproctitle("%.*s", RSTRING_LENINT(title), RSTRING_PTR(title));

    return title;
}

static void
set_arg0(VALUE val, ID id)
{
    if (origarg.argv == 0)
        rb_raise(rb_eRuntimeError, "$0 not initialized");

    rb_progname = rb_str_new_frozen(proc_setproctitle(rb_mProcess, val));
}

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

void
ruby_set_script_name(VALUE name)
{
    rb_orig_progname = rb_progname = rb_str_dup(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);
      default:
        return Qnil;
    }
}

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_module_function(rb_mProcess, "argv0", proc_argv0, 0);
    rb_define_module_function(rb_mProcess, "setproctitle", proc_setproctitle, 1);

    /*
     * ARGV contains the command line arguments used to run ruby with the
     * first value containing the name of the executable.
     *
     * A library like OptionParser can be used to process command-line
     * arguments.
     */
    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_cstr(argv[i]);

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

void *
ruby_process_options(int argc, char **argv)
{
    struct cmdline_options opt;
    VALUE iseq;
    const char *script_name = (argc > 0 && argv[0]) ? argv[0] : "ruby";

    ruby_script(script_name);  /* 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));

#ifndef HAVE_SETPROCTITLE
    {
        extern void ruby_init_setproctitle(int argc, char *argv[]);
        ruby_init_setproctitle(argc, argv);
    }
#endif

    return (void*)(struct RData*)iseq;
}

static void
fill_standard_fds(void)
{
    int f0, f1, f2, fds[2];
    struct stat buf;
    f0 = fstat(0, &buf) == -1 && errno == EBADF;
    f1 = fstat(1, &buf) == -1 && errno == EBADF;
    f2 = fstat(2, &buf) == -1 && errno == EBADF;
    if (f0) {
        if (pipe(fds) == 0) {
            close(fds[1]);
            if (fds[0] != 0) {
                dup2(fds[0], 0);
                close(fds[0]);
            }
        }
    }
    if (f1 || f2) {
        if (pipe(fds) == 0) {
            close(fds[0]);
            if (f1 && fds[1] != 1)
                dup2(fds[1], 1);
            if (f2 && fds[1] != 2)
                dup2(fds[1], 2);
            if (fds[1] != 1 && fds[1] != 2)
                close(fds[1]);
        }
    }
}

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(USE_DLN_A_OUT)
    dln_argv0 = origarg.argv[0];
#endif
    fill_standard_fds();
}

---