dir.c

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

  dir.c -

  $Author$
  created at: Wed Jan  5 09:51:01 JST 1994

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

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

#include "ruby/internal/config.h"

#include <ctype.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifndef USE_OPENDIR_AT
# if defined(HAVE_FDOPENDIR) && defined(HAVE_DIRFD) && \
    defined(HAVE_OPENAT) && defined(HAVE_FSTATAT)
#   define USE_OPENDIR_AT 1
# else
#   define USE_OPENDIR_AT 0
# endif
#endif

#ifdef HAVE_FCNTL_H
#  include <fcntl.h>
#endif

#ifndef O_CLOEXEC
#  define O_CLOEXEC 0
#endif

#undef HAVE_DIRENT_NAMLEN
#if defined HAVE_DIRENT_H && !defined _WIN32
# include <dirent.h>
# define NAMLEN(dirent) strlen((dirent)->d_name)
#elif defined HAVE_DIRECT_H && !defined _WIN32
# include <direct.h>
# define NAMLEN(dirent) strlen((dirent)->d_name)
#else
# define dirent direct
# define NAMLEN(dirent) (dirent)->d_namlen
# define HAVE_DIRENT_NAMLEN 1
# ifdef HAVE_SYS_NDIR_H
#  include <sys/ndir.h>
# endif
# ifdef HAVE_SYS_DIR_H
#  include <sys/dir.h>
# endif
# ifdef HAVE_NDIR_H
#  include <ndir.h>
# endif
# ifdef _WIN32
#  include "win32/dir.h"
# endif
#endif

#ifndef HAVE_STDLIB_H
char *getenv();
#endif

#ifndef HAVE_STRING_H
char *strchr(char*,char);
#endif

#ifdef HAVE_SYS_ATTR_H
#include <sys/attr.h>
#endif

#define USE_NAME_ON_FS_REAL_BASENAME 1	/* platform dependent APIs to
                                         * get real basenames */
#define USE_NAME_ON_FS_BY_FNMATCH 2	/* select the matching
                                         * basename by fnmatch */

#ifdef HAVE_GETATTRLIST
# define USE_NAME_ON_FS USE_NAME_ON_FS_REAL_BASENAME
# define RUP32(size) ((size)+3/4)
# define SIZEUP32(type) RUP32(sizeof(type))
#elif defined _WIN32
# define USE_NAME_ON_FS USE_NAME_ON_FS_REAL_BASENAME
#elif defined DOSISH
# define USE_NAME_ON_FS USE_NAME_ON_FS_BY_FNMATCH
#else
# define USE_NAME_ON_FS 0
#endif

#ifdef __APPLE__
# define NORMALIZE_UTF8PATH 1
# include <sys/param.h>
# include <sys/mount.h>
# include <sys/vnode.h>
#else
# define NORMALIZE_UTF8PATH 0
#endif

#include "encindex.h"
#include "id.h"
#include "internal.h"
#include "internal/array.h"
#include "internal/dir.h"
#include "internal/encoding.h"
#include "internal/error.h"
#include "internal/file.h"
#include "internal/gc.h"
#include "internal/io.h"
#include "internal/object.h"
#include "internal/imemo.h"
#include "internal/vm.h"
#include "ruby/encoding.h"
#include "ruby/ruby.h"
#include "ruby/thread.h"
#include "ruby/util.h"
#include "builtin.h"

#ifndef AT_FDCWD
# define AT_FDCWD -1
#endif

#define vm_initialized rb_cThread

/* define system APIs */
#ifdef _WIN32
# undef chdir
# define chdir(p) rb_w32_uchdir(p)
# undef mkdir
# define mkdir(p, m) rb_w32_umkdir((p), (m))
# undef rmdir
# define rmdir(p) rb_w32_urmdir(p)
# undef opendir
# define opendir(p) rb_w32_uopendir(p)
# define ruby_getcwd() rb_w32_ugetcwd(NULL, 0)
# define IS_WIN32 1
#else
# define IS_WIN32 0
#endif

#ifdef HAVE_GETATTRLIST
struct getattrlist_args {
    const char *path;
    int fd;
    struct attrlist *list;
    void *buf;
    size_t size;
    unsigned int options;
};

# define GETATTRLIST_ARGS(list_, buf_, options_) (struct getattrlist_args) \
    {.list = list_, .buf = buf_, .size = sizeof(buf_), .options = options_}

static void *
nogvl_getattrlist(void *args)
{
    struct getattrlist_args *arg = args;
    return (void *)(VALUE)getattrlist(arg->path, arg->list, arg->buf, arg->size, arg->options);
}

static int
gvl_getattrlist(struct getattrlist_args *args, const char *path)
{
    args->path = path;
    return IO_WITHOUT_GVL_INT(nogvl_getattrlist, args);
}

# ifdef HAVE_FGETATTRLIST
static void *
nogvl_fgetattrlist(void *args)
{
    struct getattrlist_args *arg = args;
    return (void *)(VALUE)fgetattrlist(arg->fd, arg->list, arg->buf, arg->size, arg->options);
}

static int
gvl_fgetattrlist(struct getattrlist_args *args, int fd)
{
    args->fd = fd;
    return IO_WITHOUT_GVL_INT(nogvl_fgetattrlist, args);
}
# endif
#endif

#if NORMALIZE_UTF8PATH
# if defined HAVE_FGETATTRLIST || !defined HAVE_GETATTRLIST
#   define need_normalization(dirp, path) need_normalization(dirp)
# else
#   define need_normalization(dirp, path) need_normalization(path)
# endif
static inline int
need_normalization(DIR *dirp, const char *path)
{
# if defined HAVE_FGETATTRLIST || defined HAVE_GETATTRLIST
    u_int32_t attrbuf[SIZEUP32(fsobj_tag_t)];
    struct attrlist al = {ATTR_BIT_MAP_COUNT, 0, ATTR_CMN_OBJTAG,};
    struct getattrlist_args args = GETATTRLIST_ARGS(&al, attrbuf, 0);
#   if defined HAVE_FGETATTRLIST
    int ret = gvl_fgetattrlist(&args, dirfd(dirp));
#   else
    int ret = gvl_getattrlist(&args, path);
#   endif
    if (!ret) {
        const fsobj_tag_t *tag = (void *)(attrbuf+1);
        switch (*tag) {
          case VT_HFS:
          case VT_CIFS:
            return TRUE;
        }
    }
# endif
    return FALSE;
}

static inline int
has_nonascii(const char *ptr, size_t len)
{
    while (len > 0) {
        if (!ISASCII(*ptr)) return 1;
        ptr++;
        --len;
    }
    return 0;
}

# define IF_NORMALIZE_UTF8PATH(something) something
#else
# define IF_NORMALIZE_UTF8PATH(something) /* nothing */
#endif

#if defined(IFTODT) && defined(DT_UNKNOWN)
# define EMULATE_IFTODT 0
#else
# define EMULATE_IFTODT 1
#endif

#if EMULATE_IFTODT
# define IFTODT(m)	(((m) & S_IFMT) / ((~S_IFMT & (S_IFMT-1)) + 1))
#endif

typedef enum {
#if !EMULATE_IFTODT
    path_exist     = DT_UNKNOWN,
    path_directory = DT_DIR,
    path_regular   = DT_REG,
    path_symlink   = DT_LNK,
#else
    path_exist,
    path_directory = IFTODT(S_IFDIR),
    path_regular   = IFTODT(S_IFREG),
    path_symlink   = IFTODT(S_IFLNK),
#endif
    path_noent = -1,
    path_unknown = -2
} rb_pathtype_t;

#define FNM_NOESCAPE	0x01
#define FNM_PATHNAME	0x02
#define FNM_DOTMATCH	0x04
#define FNM_CASEFOLD	0x08
#define FNM_EXTGLOB	0x10
#if CASEFOLD_FILESYSTEM
#define FNM_SYSCASE	FNM_CASEFOLD
#else
#define FNM_SYSCASE	0
#endif
#ifdef _WIN32
#define FNM_SHORTNAME	0x20
#else
#define FNM_SHORTNAME	0
#endif
#define FNM_GLOB_NOSORT 0x40
#define FNM_GLOB_SKIPDOT 0x80

#define FNM_NOMATCH	1
#define FNM_ERROR	2

# define Next(p, e, enc) ((p)+ rb_enc_mbclen((p), (e), (enc)))
# define Inc(p, e, enc) ((p) = Next((p), (e), (enc)))

static char *
bracket(
    const char *p, /* pattern (next to '[') */
    const char *pend,
    const char *s, /* string */
    const char *send,
    int flags,
    rb_encoding *enc)
{
    const int nocase = flags & FNM_CASEFOLD;
    const int escape = !(flags & FNM_NOESCAPE);
    unsigned int c1, c2;
    int r;
    int ok = 0, not = 0;

    if (p >= pend) return NULL;
    if (*p == '!' || *p == '^') {
        not = 1;
        p++;
    }

    while (*p != ']') {
        const char *t1 = p;
        if (escape && *t1 == '\\')
            t1++;
        if (!*t1)
            return NULL;
        p = t1 + (r = rb_enc_mbclen(t1, pend, enc));
        if (p >= pend) return NULL;
        if (p[0] == '-' && p[1] != ']') {
            const char *t2 = p + 1;
            int r2;
            if (escape && *t2 == '\\')
                t2++;
            if (!*t2)
                return NULL;
            p = t2 + (r2 = rb_enc_mbclen(t2, pend, enc));
            if (ok) continue;
            if ((r <= (send-s) && memcmp(t1, s, r) == 0) ||
                (r2 <= (send-s) && memcmp(t2, s, r2) == 0)) {
                ok = 1;
                continue;
            }
            c1 = rb_enc_codepoint(s, send, enc);
            if (nocase) c1 = rb_enc_toupper(c1, enc);
            c2 = rb_enc_codepoint(t1, pend, enc);
            if (nocase) c2 = rb_enc_toupper(c2, enc);
            if (c1 < c2) continue;
            c2 = rb_enc_codepoint(t2, pend, enc);
            if (nocase) c2 = rb_enc_toupper(c2, enc);
            if (c1 > c2) continue;
        }
        else {
            if (ok) continue;
            if (r <= (send-s) && memcmp(t1, s, r) == 0) {
                ok = 1;
                continue;
            }
            if (!nocase) continue;
            c1 = rb_enc_toupper(rb_enc_codepoint(s, send, enc), enc);
            c2 = rb_enc_toupper(rb_enc_codepoint(p, pend, enc), enc);
            if (c1 != c2) continue;
        }
        ok = 1;
    }

    return ok == not ? NULL : (char *)p + 1;
}

/* If FNM_PATHNAME is set, only path element will be matched. (up to '/' or '\0')
   Otherwise, entire string will be matched.
   End marker itself won't be compared.
   And if function succeeds, *pcur reaches end marker.
*/
#define UNESCAPE(p) (escape && *(p) == '\\' ? (p) + 1 : (p))
#define ISEND(p) (!*(p) || (pathname && *(p) == '/'))
#define RETURN(val) return *pcur = p, *scur = s, (val);

static int
fnmatch_helper(
    const char **pcur, /* pattern */
    const char **scur, /* string */
    int flags,
    rb_encoding *enc)
{
    const int period = !(flags & FNM_DOTMATCH);
    const int pathname = flags & FNM_PATHNAME;
    const int escape = !(flags & FNM_NOESCAPE);
    const int nocase = flags & FNM_CASEFOLD;

    const char *ptmp = 0;
    const char *stmp = 0;

    const char *p = *pcur;
    const char *pend = p + strlen(p);
    const char *s = *scur;
    const char *send = s + strlen(s);

    int r;

    if (period && *s == '.' && *UNESCAPE(p) != '.') /* leading period */
        RETURN(FNM_NOMATCH);

    while (1) {
        switch (*p) {
          case '*':
            do { p++; } while (*p == '*');
            if (ISEND(UNESCAPE(p))) {
                p = UNESCAPE(p);
                RETURN(0);
            }
            if (ISEND(s))
                RETURN(FNM_NOMATCH);
            ptmp = p;
            stmp = s;
            continue;

          case '?':
            if (ISEND(s))
                RETURN(FNM_NOMATCH);
            p++;
            Inc(s, send, enc);
            continue;

          case '[': {
            const char *t;
            if (ISEND(s))
                RETURN(FNM_NOMATCH);
            if ((t = bracket(p + 1, pend, s, send, flags, enc)) != 0) {
                p = t;
                Inc(s, send, enc);
                continue;
            }
            goto failed;
          }
        }

        /* ordinary */
        p = UNESCAPE(p);
        if (ISEND(s))
            RETURN(ISEND(p) ? 0 : FNM_NOMATCH);
        if (ISEND(p))
            goto failed;
        r = rb_enc_precise_mbclen(p, pend, enc);
        if (!MBCLEN_CHARFOUND_P(r))
            goto failed;
        if (r <= (send-s) && memcmp(p, s, r) == 0) {
            p += r;
            s += r;
            continue;
        }
        if (!nocase) goto failed;
        if (rb_enc_toupper(rb_enc_codepoint(p, pend, enc), enc) !=
            rb_enc_toupper(rb_enc_codepoint(s, send, enc), enc))
            goto failed;
        p += r;
        Inc(s, send, enc);
        continue;

      failed: /* try next '*' position */
        if (ptmp && stmp) {
            p = ptmp;
            Inc(stmp, send, enc); /* !ISEND(*stmp) */
            s = stmp;
            continue;
        }
        RETURN(FNM_NOMATCH);
    }
}

static int
fnmatch(
    const char *pattern,
    rb_encoding *enc,
    const char *string,
    int flags)
{
    const char *p = pattern;
    const char *s = string;
    const char *send = s + strlen(string);
    const int period = !(flags & FNM_DOTMATCH);
    const int pathname = flags & FNM_PATHNAME;

    const char *ptmp = 0;
    const char *stmp = 0;

    if (pathname) {
        while (1) {
            if (p[0] == '*' && p[1] == '*' && p[2] == '/') {
                do { p += 3; } while (p[0] == '*' && p[1] == '*' && p[2] == '/');
                ptmp = p;
                stmp = s;
            }
            if (fnmatch_helper(&p, &s, flags, enc) == 0) {
                while (*s && *s != '/') Inc(s, send, enc);
                if (*p && *s) {
                    p++;
                    s++;
                    continue;
                }
                if (!*p && !*s)
                    return 0;
            }
            /* failed : try next recursion */
            if (ptmp && stmp && !(period && *stmp == '.')) {
                while (*stmp && *stmp != '/') Inc(stmp, send, enc);
                if (*stmp) {
                    p = ptmp;
                    stmp++;
                    s = stmp;
                    continue;
                }
            }
            return FNM_NOMATCH;
        }
    }
    else
        return fnmatch_helper(&p, &s, flags, enc);
}

VALUE rb_cDir;
static VALUE sym_directory, sym_link, sym_file, sym_unknown;

#if defined(DT_BLK) || defined(S_IFBLK)
static VALUE sym_block_device;
#endif
#if defined(DT_CHR) || defined(S_IFCHR)
static VALUE sym_character_device;
#endif
#if defined(DT_FIFO) || defined(S_IFIFO)
static VALUE sym_fifo;
#endif
#if defined(DT_SOCK) || defined(S_IFSOCK)
static VALUE sym_socket;
#endif

struct dir_data {
    DIR *dir;
    const VALUE path;
    rb_encoding *enc;
};

static void
dir_free(void *ptr)
{
    struct dir_data *dir = ptr;

    if (dir->dir) closedir(dir->dir);
}

RUBY_REFERENCES(dir_refs) = {
    RUBY_REF_EDGE(struct dir_data, path),
    RUBY_REF_END
};

static const rb_data_type_t dir_data_type = {
    "dir",
    {
        RUBY_REFS_LIST_PTR(dir_refs),
        dir_free,
        NULL, // Nothing allocated externally, so don't need a memsize function
    },
    0, NULL, RUBY_TYPED_WB_PROTECTED | RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_DECL_MARKING | RUBY_TYPED_EMBEDDABLE
};

static VALUE dir_close(VALUE);

static VALUE
dir_s_alloc(VALUE klass)
{
    struct dir_data *dirp;
    VALUE obj = TypedData_Make_Struct(klass, struct dir_data, &dir_data_type, dirp);

    dirp->dir = NULL;
    RB_OBJ_WRITE(obj, &dirp->path, Qnil);
    dirp->enc = NULL;

    return obj;
}

static void *
nogvl_opendir(void *ptr)
{
    const char *path = ptr;

    return opendir(path);
}

static DIR *
opendir_without_gvl(const char *path)
{
    if (vm_initialized) {
        union { const void *in; void *out; } u;

        u.in = path;

        return IO_WITHOUT_GVL(nogvl_opendir, u.out);
    }
    else
        return opendir(path);
}

static void
close_dir_data(struct dir_data *dp)
{
    if (dp->dir) {
        if (closedir(dp->dir) < 0) {
            dp->dir = NULL;
            rb_sys_fail("closedir");
        }
        dp->dir = NULL;
    }
}

static void
check_closedir(DIR *dirp)
{
    if (closedir(dirp) < 0)
        rb_sys_fail("closedir");
}

static VALUE
dir_initialize(rb_execution_context_t *ec, VALUE dir, VALUE dirname, VALUE enc)
{
    struct dir_data *dp;
    VALUE orig;
    const char *path;
    rb_encoding *fsenc = NIL_P(enc) ? rb_filesystem_encoding() : rb_to_encoding(enc);

    FilePathValue(dirname);
    orig = rb_str_dup_frozen(dirname);
    dirname = rb_str_encode_ospath(dirname);
    dirname = rb_str_dup_frozen(dirname);

    TypedData_Get_Struct(dir, struct dir_data, &dir_data_type, dp);
    close_dir_data(dp);
    RB_OBJ_WRITE(dir, &dp->path, Qnil);
    dp->enc = fsenc;
    path = RSTRING_PTR(dirname);
    dp->dir = opendir_without_gvl(path);
    if (dp->dir == NULL) {
        int e = errno;
        if (rb_gc_for_fd(e)) {
            dp->dir = opendir_without_gvl(path);
        }
#ifdef HAVE_GETATTRLIST
        else if (e == EIO) {
            u_int32_t attrbuf[1];
            struct attrlist al = {ATTR_BIT_MAP_COUNT, 0};
            struct getattrlist_args args = GETATTRLIST_ARGS(&al, attrbuf, FSOPT_NOFOLLOW);
            if (gvl_getattrlist(&args, path) == 0) {
                dp->dir = opendir_without_gvl(path);
            }
        }
#endif
        if (dp->dir == NULL) {
            RB_GC_GUARD(dirname);
            rb_syserr_fail_path(e, orig);
        }
    }
    RB_OBJ_WRITE(dir, &dp->path, orig);

    return dir;
}

static VALUE
dir_s_open(rb_execution_context_t *ec, VALUE klass, VALUE dirname, VALUE enc)
{
    struct dir_data *dp;
    VALUE dir = TypedData_Make_Struct(klass, struct dir_data, &dir_data_type, dp);

    dir_initialize(ec, dir, dirname, enc);

    return dir;
}

static VALUE
dir_s_close(rb_execution_context_t *ec, VALUE klass, VALUE dir)
{
    return dir_close(dir);
}

# if defined(HAVE_FDOPENDIR) && defined(HAVE_DIRFD)
static void *
nogvl_fdopendir(void *fd)
{
    return fdopendir((int)(VALUE)fd);
}

/*
 * call-seq:
 *   Dir.for_fd(fd) -> dir
 *
 * Returns a new \Dir object representing the directory specified by the given
 * integer directory file descriptor +fd+:
 *
 *   d0 = Dir.new('..')
 *   d1 = Dir.for_fd(d0.fileno)
 *
 * Note that the returned +d1+ does not have an associated path:
 *
 *   d0.path # => '..'
 *   d1.path # => nil
 *
 * This method uses the
 * {fdopendir()}[https://www.man7.org/linux/man-pages/man3/fdopendir.3p.html]
 * function defined by POSIX 2008;
 * the method is not implemented on non-POSIX platforms (raises NotImplementedError).
 */
static VALUE
dir_s_for_fd(VALUE klass, VALUE fd)
{
    struct dir_data *dp;
    VALUE dir = TypedData_Make_Struct(klass, struct dir_data, &dir_data_type, dp);

    if (!(dp->dir = IO_WITHOUT_GVL(nogvl_fdopendir, (void *)(VALUE)NUM2INT(fd)))) {
        rb_sys_fail("fdopendir");
        UNREACHABLE_RETURN(Qnil);
    }

    RB_OBJ_WRITE(dir, &dp->path, Qnil);
    return dir;
}
#else
#define dir_s_for_fd rb_f_notimplement
#endif

NORETURN(static void dir_closed(void));

static void
dir_closed(void)
{
    rb_raise(rb_eIOError, "closed directory");
}

static struct dir_data *
dir_get(VALUE dir)
{
    rb_check_frozen(dir);
    return rb_check_typeddata(dir, &dir_data_type);
}

static struct dir_data *
dir_check(VALUE dir)
{
    struct dir_data *dirp = dir_get(dir);
    if (!dirp->dir) dir_closed();
    return dirp;
}

#define GetDIR(obj, dirp) ((dirp) = dir_check(obj))


/*
 * call-seq:
 *   inspect -> string
 *
 * Returns a string description of +self+:
 *
 *   Dir.new('example').inspect # => "#<Dir:example>"
 *
 */
static VALUE
dir_inspect(VALUE dir)
{
    struct dir_data *dirp;

    TypedData_Get_Struct(dir, struct dir_data, &dir_data_type, dirp);
    if (!NIL_P(dirp->path)) {
        VALUE str = rb_str_new_cstr("#<");
        rb_str_append(str, rb_class_name(CLASS_OF(dir)));
        rb_str_cat2(str, ":");
        rb_str_append(str, dirp->path);
        rb_str_cat2(str, ">");
        return str;
    }
    return rb_funcallv(dir, idTo_s, 0, 0);
}

/* Workaround for Solaris 10 that does not have dirfd.
   Note: Solaris 11 (POSIX.1-2008 compliant) has dirfd(3C).
 */
#if defined(__sun) && !defined(HAVE_DIRFD)
# if defined(HAVE_DIR_D_FD)
#  define dirfd(x) ((x)->d_fd)
#  define HAVE_DIRFD 1
# elif defined(HAVE_DIR_DD_FD)
#  define dirfd(x) ((x)->dd_fd)
#  define HAVE_DIRFD 1
# endif
#endif

#ifdef HAVE_DIRFD
/*
 * call-seq:
 *   fileno -> integer
 *
 * Returns the file descriptor used in <em>dir</em>.
 *
 *   d = Dir.new('..')
 *   d.fileno # => 8
 *
 * This method uses the
 * {dirfd()}[https://www.man7.org/linux/man-pages/man3/dirfd.3.html]
 * function defined by POSIX 2008;
 * the method is not implemented on non-POSIX platforms (raises NotImplementedError).
 */
static VALUE
dir_fileno(VALUE dir)
{
    struct dir_data *dirp;
    int fd;

    GetDIR(dir, dirp);
    fd = dirfd(dirp->dir);
    if (fd == -1)
        rb_sys_fail("dirfd");
    return INT2NUM(fd);
}
#else
#define dir_fileno rb_f_notimplement
#endif

/*
 * call-seq:
 *   path -> string or nil
 *
 * Returns the +dirpath+ string that was used to create +self+
 * (or +nil+ if created by method Dir.for_fd):
 *
 *   Dir.new('example').path # => "example"
 *
 */
static VALUE
dir_path(VALUE dir)
{
    struct dir_data *dirp;

    TypedData_Get_Struct(dir, struct dir_data, &dir_data_type, dirp);
    if (NIL_P(dirp->path)) return Qnil;
    return rb_str_dup(dirp->path);
}

#if defined _WIN32
static int
fundamental_encoding_p(rb_encoding *enc)
{
    switch (rb_enc_to_index(enc)) {
      case ENCINDEX_ASCII_8BIT:
      case ENCINDEX_US_ASCII:
      case ENCINDEX_UTF_8:
        return TRUE;
      default:
        return FALSE;
    }
}
# define READDIR(dir, enc) rb_w32_readdir((dir), (enc))
# define READDIR_NOGVL READDIR
#else
NORETURN(static void *sys_failure(void *function));
static void *
sys_failure(void *function)
{
    rb_sys_fail(function);
}

static void *
nogvl_readdir(void *dir)
{
    rb_errno_set(0);
    if ((dir = readdir(dir)) == NULL) {
        if (rb_errno())
            rb_thread_call_with_gvl(sys_failure, (void *)"readdir");
    }
    return dir;
}

# define READDIR(dir, enc) IO_WITHOUT_GVL(nogvl_readdir, (void *)(dir))
# define READDIR_NOGVL(dir, enc) nogvl_readdir((dir))
#endif

/* safe to use without GVL */
static int
to_be_skipped(const struct dirent *dp)
{
    const char *name = dp->d_name;
    if (name[0] != '.') return FALSE;
#ifdef HAVE_DIRENT_NAMLEN
    switch (NAMLEN(dp)) {
      case 2:
        if (name[1] != '.') return FALSE;
      case 1:
        return TRUE;
      default:
        break;
    }
#else
    if (!name[1]) return TRUE;
    if (name[1] != '.') return FALSE;
    if (!name[2]) return TRUE;
#endif
    return FALSE;
}

/*
 * call-seq:
 *   read -> string or nil
 *
 * Reads and returns the next entry name from +self+;
 * returns +nil+ if at end-of-stream;
 * see {Dir As Stream-Like}[rdoc-ref:Dir@Dir+As+Stream-Like]:
 *
 *   dir = Dir.new('example')
 *   dir.read # => "."
 *   dir.read # => ".."
 *   dir.read # => "config.h"
 *
 */
static VALUE
dir_read(VALUE dir)
{
    struct dir_data *dirp;
    struct dirent *dp;

    GetDIR(dir, dirp);
    rb_errno_set(0);
    if ((dp = READDIR(dirp->dir, dirp->enc)) != NULL) {
        return rb_external_str_new_with_enc(dp->d_name, NAMLEN(dp), dirp->enc);
    }
    else {
        int e = errno;
        if (e != 0) rb_syserr_fail(e, 0);
        return Qnil;		/* end of stream */
    }
}

struct dir_entry_args {
    struct dir_data *dirp;
    struct dirent *dp;
};

static VALUE dir_each_entry(VALUE, VALUE (*)(VALUE, VALUE, struct dir_entry_args *), VALUE, int);

static VALUE
dir_yield(VALUE arg, VALUE path, struct dir_entry_args *_unused)
{
    return rb_yield(path);
}

static int do_lstat(int fd, const char *path, struct stat *pst, int flags, rb_encoding *enc);

static VALUE
dir_yield_with_type(VALUE arg, VALUE path, struct dir_entry_args *dir_entry)
{
    VALUE type;
    switch (dir_entry->dp->d_type) {
#ifdef DT_BLK
      case DT_BLK:
        type = sym_block_device;
        break;
#endif
#ifdef DT_CHR
      case DT_CHR:
        type = sym_character_device;
        break;
#endif
      case DT_DIR:
        type = sym_directory;
        break;
#ifdef DT_FIFO
      case DT_FIFO:
        type = sym_fifo;
        break;
#endif
      case DT_LNK:
        type = sym_link;
        break;
      case DT_REG:
        type = sym_file;
        break;
#ifdef DT_SOCK
      case DT_SOCK:
        type = sym_socket;
        break;
#endif
      default:
        type = sym_unknown;
        break;
    }

#ifdef HAVE_DIRFD
    if (RUBY_DEBUG || RB_UNLIKELY(type == sym_unknown)) {
        struct stat st;
        if (do_lstat(dirfd(dir_entry->dirp->dir), dir_entry->dp->d_name, &st, 0, rb_filesystem_encoding()) == 0) {
            switch (st.st_mode & S_IFMT) {
              case S_IFDIR:
                type = sym_directory;
                break;
              case S_IFLNK:
                type = sym_link;
                break;
              case S_IFREG:
                type = sym_file;
                break;
#ifdef S_IFSOCK
              case S_IFSOCK:
                type = sym_socket;
                break;
#endif
#ifdef S_IFIFO
              case S_IFIFO:
                type = sym_fifo;
                break;
#endif
#ifdef S_IFBLK
              case S_IFBLK:
                type = sym_block_device;
                break;
#endif
#ifdef S_IFCHR
              case S_IFCHR:
                type = sym_character_device;
                break;
#endif
              default:
                break;
            }
        }
    }
#endif // HAVE_DIRFD

    if (NIL_P(arg)) {
        return rb_yield_values(2, path, type);
    }
    else {
        return rb_ary_push(arg, rb_assoc_new(path, type));
    }
}

/*
 * call-seq:
 *   each {|entry_name| ... } -> self
 *
 * Calls the block with each entry name in +self+:
 *
 *   Dir.new('example').each {|entry_name| p entry_name }
 *
 * Output:

 *   "."
 *   ".."
 *   "config.h"
 *   "lib"
 *   "main.rb"
 *
 * With no block given, returns an Enumerator.
 *
 */
static VALUE
dir_each(VALUE dir)
{
    RETURN_ENUMERATOR(dir, 0, 0);
    return dir_each_entry(dir, dir_yield, Qnil, FALSE);
}

static VALUE
dir_each_entry(VALUE dir, VALUE (*each)(VALUE, VALUE, struct dir_entry_args *), VALUE arg, int children_only)
{
    struct dir_data *dirp;
    struct dirent *dp;
    IF_NORMALIZE_UTF8PATH(int norm_p);

    GetDIR(dir, dirp);
    rewinddir(dirp->dir);
    IF_NORMALIZE_UTF8PATH(norm_p = need_normalization(dirp->dir, RSTRING_PTR(dirp->path)));
    while ((dp = READDIR(dirp->dir, dirp->enc)) != NULL) {
        const char *name = dp->d_name;
        size_t namlen = NAMLEN(dp);
        VALUE path;

        if (children_only && name[0] == '.') {
            if (namlen == 1) continue; /* current directory */
            if (namlen == 2 && name[1] == '.') continue; /* parent directory */
        }
#if NORMALIZE_UTF8PATH
        if (norm_p && has_nonascii(name, namlen) &&
            !NIL_P(path = rb_str_normalize_ospath(name, namlen))) {
            path = rb_external_str_with_enc(path, dirp->enc);
        }
        else
#endif
        path = rb_external_str_new_with_enc(name, namlen, dirp->enc);
        struct dir_entry_args each_args = {
            .dirp = dirp,
            .dp = dp,
        };
        (*each)(arg, path, &each_args);
    }
    return dir;
}

#ifdef HAVE_TELLDIR
/*
 * call-seq:
 *   tell -> integer
 *
 * Returns the current position of +self+;
 * see {Dir As Stream-Like}[rdoc-ref:Dir@Dir+As+Stream-Like]:
 *
 *   dir = Dir.new('example')
 *   dir.tell  # => 0
 *   dir.read  # => "."
 *   dir.tell  # => 1
 *
 */
static VALUE
dir_tell(VALUE dir)
{
    struct dir_data *dirp;
    long pos;

    GetDIR(dir, dirp);
    if((pos = telldir(dirp->dir)) < 0)
        rb_sys_fail("telldir");
    return rb_int2inum(pos);
}
#else
#define dir_tell rb_f_notimplement
#endif

#ifdef HAVE_SEEKDIR
/*
 * call-seq:
 *   seek(position) -> self
 *
 * Sets the position in +self+ and returns +self+.
 * The value of +position+ should have been returned from an earlier call to #tell;
 * if not, the return values from subsequent calls to #read are unspecified.
 *
 * See {Dir As Stream-Like}[rdoc-ref:Dir@Dir+As+Stream-Like].
 *
 * Examples:
 *
 *   dir = Dir.new('example')
 *   dir.pos      # => 0
 *   dir.seek(3)  # => #<Dir:example>
 *   dir.pos      # => 3
 *   dir.seek(30) # => #<Dir:example>
 *   dir.pos      # => 5
 *
 */
static VALUE
dir_seek(VALUE dir, VALUE pos)
{
    struct dir_data *dirp;
    long p = NUM2LONG(pos);

    GetDIR(dir, dirp);
    seekdir(dirp->dir, p);
    return dir;
}
#else
#define dir_seek rb_f_notimplement
#endif

#ifdef HAVE_SEEKDIR
/*
 * call-seq:
 *   pos = position -> integer
 *
 * Sets the position in +self+ and returns +position+.
 * The value of +position+ should have been returned from an earlier call to #tell;
 * if not, the return values from subsequent calls to #read are unspecified.
 *
 * See {Dir As Stream-Like}[rdoc-ref:Dir@Dir+As+Stream-Like].
 *
 * Examples:
 *
 *   dir = Dir.new('example')
 *   dir.pos      # => 0
 *   dir.pos = 3  # => 3
 *   dir.pos      # => 3
 *   dir.pos = 30 # => 30
 *   dir.pos      # => 5
 *
 */
static VALUE
dir_set_pos(VALUE dir, VALUE pos)
{
    dir_seek(dir, pos);
    return pos;
}
#else
#define dir_set_pos rb_f_notimplement
#endif

/*
 * call-seq:
 *   rewind -> self
 *
 * Sets the position in +self+ to zero;
 * see {Dir As Stream-Like}[rdoc-ref:Dir@Dir+As+Stream-Like]:
 *
 *   dir = Dir.new('example')
 *   dir.read    # => "."
 *   dir.read    # => ".."
 *   dir.pos     # => 2
 *   dir.rewind  # => #<Dir:example>
 *   dir.pos     # => 0
 *
 */
static VALUE
dir_rewind(VALUE dir)
{
    struct dir_data *dirp;

    GetDIR(dir, dirp);
    rewinddir(dirp->dir);
    return dir;
}

/*
 * call-seq:
 *   close -> nil
 *
 * Closes the stream in +self+, if it is open, and returns +nil+;
 * ignored if +self+ is already closed:
 *
 *   dir = Dir.new('example')
 *   dir.read     # => "."
 *   dir.close     # => nil
 *   dir.close     # => nil
 *   dir.read # Raises IOError.
 *
 */
static VALUE
dir_close(VALUE dir)
{
    struct dir_data *dirp;

    dirp = dir_get(dir);
    if (!dirp->dir) return Qnil;
    close_dir_data(dirp);

    return Qnil;
}

static void *
nogvl_chdir(void *ptr)
{
    const char *path = ptr;

    return (void *)(VALUE)chdir(path);
}

static void
dir_chdir0(VALUE path)
{
    if (IO_WITHOUT_GVL_INT(nogvl_chdir, (void*)RSTRING_PTR(path)) < 0)
        rb_sys_fail_path(path);
}

static struct {
    VALUE thread;
    VALUE path;
    int line;
    int blocking;
} chdir_lock = {
    .blocking = 0, .thread = Qnil,
    .path = Qnil, .line = 0,
};

static void
chdir_enter(void)
{
    if (chdir_lock.blocking == 0) {
        chdir_lock.path = rb_source_location(&chdir_lock.line);
    }
    chdir_lock.blocking++;
    if (NIL_P(chdir_lock.thread)) {
        chdir_lock.thread = rb_thread_current();
    }
}

static void
chdir_leave(void)
{
    chdir_lock.blocking--;
    if (chdir_lock.blocking == 0) {
        chdir_lock.thread = Qnil;
        chdir_lock.path = Qnil;
        chdir_lock.line = 0;
    }
}

static int
chdir_alone_block_p(void)
{
    int block_given = rb_block_given_p();
    if (chdir_lock.blocking > 0) {
        if (rb_thread_current() != chdir_lock.thread)
            rb_raise(rb_eRuntimeError, "conflicting chdir during another chdir block");
        if (!block_given) {
            if (!NIL_P(chdir_lock.path)) {
                rb_warn("conflicting chdir during another chdir block\n"
                        "%" PRIsVALUE ":%d: note: previous chdir was here",
                        chdir_lock.path, chdir_lock.line);
            }
            else {
                rb_warn("conflicting chdir during another chdir block");
            }
        }
    }
    return block_given;
}

struct chdir_data {
    VALUE old_path, new_path;
    int done;
    bool yield_path;
};

static VALUE
chdir_yield(VALUE v)
{
    struct chdir_data *args = (void *)v;
    dir_chdir0(args->new_path);
    args->done = TRUE;
    chdir_enter();
    return args->yield_path ? rb_yield(args->new_path) : rb_yield_values2(0, NULL);
}

static VALUE
chdir_restore(VALUE v)
{
    struct chdir_data *args = (void *)v;
    if (args->done) {
        chdir_leave();
        dir_chdir0(args->old_path);
    }
    return Qnil;
}

static VALUE
chdir_path(VALUE path, bool yield_path)
{
    if (chdir_alone_block_p()) {
        struct chdir_data args;

        args.old_path = rb_str_encode_ospath(rb_dir_getwd());
        args.new_path = path;
        args.done = FALSE;
        args.yield_path = yield_path;
        return rb_ensure(chdir_yield, (VALUE)&args, chdir_restore, (VALUE)&args);
    }
    else {
        char *p = RSTRING_PTR(path);
        int r = IO_WITHOUT_GVL_INT(nogvl_chdir, p);
        if (r < 0)
            rb_sys_fail_path(path);
    }

    return INT2FIX(0);
}

/*
 * call-seq:
 *   Dir.chdir(new_dirpath) -> 0
 *   Dir.chdir -> 0
 *   Dir.chdir(new_dirpath) {|new_dirpath| ... } -> object
 *   Dir.chdir {|cur_dirpath| ... } -> object
 *
 * Changes the current working directory.
 *
 * With argument +new_dirpath+ and no block,
 * changes to the given +dirpath+:
 *
 *   Dir.pwd         # => "/example"
 *   Dir.chdir('..') # => 0
 *   Dir.pwd         # => "/"
 *
 * With no argument and no block:
 *
 * - Changes to the value of environment variable +HOME+ if defined.
 * - Otherwise changes to the value of environment variable +LOGDIR+ if defined.
 * - Otherwise makes no change.
 *
 * With argument +new_dirpath+ and a block, temporarily changes the working directory:
 *
 * - Calls the block with the argument.
 * - Changes to the given directory.
 * - Executes the block (yielding the new path).
 * - Restores the previous working directory.
 * - Returns the block's return value.
 *
 * Example:
 *
 *   Dir.chdir('/var/spool/mail')
 *   Dir.pwd   # => "/var/spool/mail"
 *   Dir.chdir('/tmp') do
 *     Dir.pwd # => "/tmp"
 *   end
 *   Dir.pwd   # => "/var/spool/mail"
 *
 * With no argument and a block,
 * calls the block with the current working directory (string)
 * and returns the block's return value.
 *
 * Calls to \Dir.chdir with blocks may be nested:
 *
 *   Dir.chdir('/var/spool/mail')
 *   Dir.pwd     # => "/var/spool/mail"
 *   Dir.chdir('/tmp') do
 *     Dir.pwd   # => "/tmp"
 *     Dir.chdir('/usr') do
 *       Dir.pwd # => "/usr"
 *     end
 *     Dir.pwd   # => "/tmp"
 *   end
 *   Dir.pwd     # => "/var/spool/mail"
 *
 * In a multi-threaded program an error is raised if a thread attempts
 * to open a +chdir+ block while another thread has one open,
 * or a call to +chdir+ without a block occurs inside
 * a block passed to +chdir+ (even in the same thread).
 *
 * Raises an exception if the target directory does not exist.
 */
static VALUE
dir_s_chdir(int argc, VALUE *argv, VALUE obj)
{
    VALUE path = Qnil;

    if (rb_check_arity(argc, 0, 1) == 1) {
        path = rb_str_encode_ospath(rb_get_path(argv[0]));
    }
    else {
        const char *dist = getenv("HOME");
        if (!dist) {
            dist = getenv("LOGDIR");
            if (!dist) rb_raise(rb_eArgError, "HOME/LOGDIR not set");
        }
        path = rb_str_new2(dist);
    }

    return chdir_path(path, true);
}

#if defined(HAVE_FCHDIR) && defined(HAVE_DIRFD) && HAVE_FCHDIR && HAVE_DIRFD
static void *
nogvl_fchdir(void *ptr)
{
    const int *fd = ptr;

    return (void *)(VALUE)fchdir(*fd);
}

static void
dir_fchdir(int fd)
{
    if (IO_WITHOUT_GVL_INT(nogvl_fchdir, (void *)&fd) < 0)
        rb_sys_fail("fchdir");
}

struct fchdir_data {
    VALUE old_dir;
    int fd;
    int done;
};

static VALUE
fchdir_yield(VALUE v)
{
    struct fchdir_data *args = (void *)v;
    dir_fchdir(args->fd);
    args->done = TRUE;
    chdir_enter();
    return rb_yield_values(0);
}

static VALUE
fchdir_restore(VALUE v)
{
    struct fchdir_data *args = (void *)v;
    if (args->done) {
        chdir_leave();
        dir_fchdir(RB_NUM2INT(dir_fileno(args->old_dir)));
    }
    dir_close(args->old_dir);
    return Qnil;
}

/*
 * call-seq:
 *   Dir.fchdir(fd) -> 0
 *   Dir.fchdir(fd) { ... } -> object
 *
 * Changes the current working directory to the directory
 * specified by the integer file descriptor +fd+.
 *
 * When passing a file descriptor over a UNIX socket or to a child process,
 * using +fchdir+ instead of +chdir+ avoids the
 * {time-of-check to time-of-use vulnerability}[https://en.wikipedia.org/wiki/Time-of-check_to_time-of-use]
 *
 * With no block, changes to the directory given by +fd+:
 *
 *   Dir.chdir('/var/spool/mail')
 *   Dir.pwd # => "/var/spool/mail"
 *   dir  = Dir.new('/usr')
 *   fd = dir.fileno
 *   Dir.fchdir(fd)
 *   Dir.pwd # => "/usr"
 *
 * With a block, temporarily changes the working directory:
 *
 * - Calls the block with the argument.
 * - Changes to the given directory.
 * - Executes the block (yields no args).
 * - Restores the previous working directory.
 * - Returns the block's return value.
 *
 * Example:
 *
 *   Dir.chdir('/var/spool/mail')
 *   Dir.pwd # => "/var/spool/mail"
 *   dir  = Dir.new('/tmp')
 *   fd = dir.fileno
 *   Dir.fchdir(fd) do
 *     Dir.pwd # => "/tmp"
 *   end
 *   Dir.pwd # => "/var/spool/mail"
 *
 * This method uses the
 * {fchdir()}[https://www.man7.org/linux/man-pages/man3/fchdir.3p.html]
 * function defined by POSIX 2008;
 * the method is not implemented on non-POSIX platforms (raises NotImplementedError).
 *
 * Raises an exception if the file descriptor is not valid.
 *
 * In a multi-threaded program an error is raised if a thread attempts
 * to open a +chdir+ block while another thread has one open,
 * or a call to +chdir+ without a block occurs inside
 * a block passed to +chdir+ (even in the same thread).
 */
static VALUE
dir_s_fchdir(VALUE klass, VALUE fd_value)
{
    int fd = RB_NUM2INT(fd_value);

    if (chdir_alone_block_p()) {
        struct fchdir_data args;
        args.old_dir = dir_s_alloc(klass);
        dir_initialize(NULL, args.old_dir, rb_fstring_cstr("."), Qnil);
        args.fd = fd;
        args.done = FALSE;
        return rb_ensure(fchdir_yield, (VALUE)&args, fchdir_restore, (VALUE)&args);
    }
    else {
        int r = IO_WITHOUT_GVL_INT(nogvl_fchdir, &fd);
        if (r < 0)
            rb_sys_fail("fchdir");
    }

    return INT2FIX(0);
}
#else
#define dir_s_fchdir rb_f_notimplement
#endif

/*
 * call-seq:
 *   chdir -> 0
 *   chdir { ... } -> object
 *
 * Changes the current working directory to +self+:
 *
 *   Dir.pwd # => "/"
 *   dir = Dir.new('example')
 *   dir.chdir
 *   Dir.pwd # => "/example"
 *
 * With a block, temporarily changes the working directory:
 *
 * - Calls the block.
 * - Changes to the given directory.
 * - Executes the block (yields no args).
 * - Restores the previous working directory.
 * - Returns the block's return value.
 *
 * Uses Dir.fchdir if available, and Dir.chdir if not, see those
 * methods for caveats.
 */
static VALUE
dir_chdir(VALUE dir)
{
#if defined(HAVE_FCHDIR) && defined(HAVE_DIRFD) && HAVE_FCHDIR && HAVE_DIRFD
    return dir_s_fchdir(rb_cDir, dir_fileno(dir));
#else
    return chdir_path(dir_get(dir)->path, false);
#endif
}

static VALUE last_cwd;

#ifndef _WIN32
static VALUE
getcwd_to_str(VALUE arg)
{
    const char *path = (const char *)arg;
#ifdef __APPLE__
    return rb_str_normalize_ospath(path, strlen(path));
#else
    return rb_str_new2(path);
#endif
}

static VALUE
getcwd_xfree(VALUE arg)
{
    xfree((void *)arg);
    return Qnil;
}

static VALUE
rb_dir_getwd_ospath_slowpath(void)
{
    char *path = ruby_getcwd();
    return rb_ensure(getcwd_to_str, (VALUE)path, getcwd_xfree, (VALUE)path);
}

VALUE
rb_dir_getwd_ospath(void)
{
    char buf[PATH_MAX];
    char *path = getcwd(buf, PATH_MAX);
    if (!path) {
        return rb_dir_getwd_ospath_slowpath();
    }

    VALUE cached_cwd = RUBY_ATOMIC_VALUE_LOAD(last_cwd);

    if (!cached_cwd || strcmp(RSTRING_PTR(cached_cwd), path) != 0) {
#ifdef __APPLE__
        cached_cwd = rb_str_normalize_ospath(path, strlen(path));
#else
        cached_cwd = rb_str_new2(path);
#endif
        rb_str_freeze(cached_cwd);
        RUBY_ATOMIC_VALUE_SET(last_cwd, cached_cwd);
    }
    return cached_cwd;
}
#endif

VALUE
rb_dir_getwd(void)
{
    rb_encoding *fs = rb_filesystem_encoding();
    int fsenc = rb_enc_to_index(fs);
    VALUE cwd = rb_str_new_shared(rb_dir_getwd_ospath());

    switch (fsenc) {
      case ENCINDEX_US_ASCII:
        fsenc = ENCINDEX_ASCII_8BIT;
      case ENCINDEX_ASCII_8BIT:
        break;
#if defined _WIN32 || defined __APPLE__
      default:
        return rb_str_conv_enc(cwd, NULL, fs);
#endif
    }
    return rb_enc_associate_index(cwd, fsenc);
}

/*
 * call-seq:
 *   Dir.pwd -> string
 *
 * Returns the path to the current working directory:
 *
 *   Dir.chdir("/tmp") # => 0
 *   Dir.pwd           # => "/tmp"
 *
 */
static VALUE
dir_s_getwd(VALUE dir)
{
    return rb_dir_getwd();
}

static VALUE
check_dirname(VALUE dir)
{
    VALUE d = dir;
    char *path, *pend;
    long len;
    rb_encoding *enc;

    FilePathValue(d);
    enc = rb_enc_get(d);
    RSTRING_GETMEM(d, path, len);
    pend = path + len;
    pend = rb_enc_path_end(rb_enc_path_skip_prefix(path, pend, enc), pend, enc);
    if (pend - path < len) {
        d = rb_str_subseq(d, 0, pend - path);
        StringValueCStr(d);
    }
    return rb_str_encode_ospath(d);
}

#if defined(HAVE_CHROOT)
static void *
nogvl_chroot(void *dirname)
{
    return (void *)(VALUE)chroot((const char *)dirname);
}

/*
 * call-seq:
 *   Dir.chroot(dirpath) -> 0
 *
 * Changes the root directory of the calling process to that specified in +dirpath+.
 * The new root directory is used for pathnames beginning with <tt>'/'</tt>.
 * The root directory is inherited by all children of the calling process.
 *
 * Only a privileged process may call +chroot+.
 *
 * See {Linux chroot}[https://man7.org/linux/man-pages/man2/chroot.2.html].
 */
static VALUE
dir_s_chroot(VALUE dir, VALUE path)
{
    path = check_dirname(path);
    if (IO_WITHOUT_GVL_INT(nogvl_chroot, (void *)RSTRING_PTR(path)) == -1)
        rb_sys_fail_path(path);

    return INT2FIX(0);
}
#else
#define dir_s_chroot rb_f_notimplement
#endif

struct mkdir_arg {
    const char *path;
    mode_t mode;
};

static void *
nogvl_mkdir(void *ptr)
{
    struct mkdir_arg *m = ptr;

    return (void *)(VALUE)mkdir(m->path, m->mode);
}

/*
 * call-seq:
 *   Dir.mkdir(dirpath, permissions = 0775) -> 0
 *
 * Creates a directory in the underlying file system
 * at +dirpath+ with the given +permissions+;
 * returns zero:
 *
 *   Dir.mkdir('foo')
 *   File.stat(Dir.new('foo')).mode.to_s(8)[1..4] # => "0755"
 *   Dir.mkdir('bar', 0644)
 *   File.stat(Dir.new('bar')).mode.to_s(8)[1..4] # => "0644"
 *
 * See {File Permissions}[rdoc-ref:File@File+Permissions].
 * Note that argument +permissions+ is ignored on Windows.
 */
static VALUE
dir_s_mkdir(int argc, VALUE *argv, VALUE obj)
{
    struct mkdir_arg m;
    VALUE path, vmode;
    int r;

    if (rb_scan_args(argc, argv, "11", &path, &vmode) == 2) {
        m.mode = NUM2MODET(vmode);
    }
    else {
        m.mode = 0777;
    }

    path = check_dirname(path);
    m.path = RSTRING_PTR(path);
    r = IO_WITHOUT_GVL_INT(nogvl_mkdir, &m);
    if (r < 0)
        rb_sys_fail_path(path);

    return INT2FIX(0);
}

static void *
nogvl_rmdir(void *ptr)
{
    const char *path = ptr;

    return (void *)(VALUE)rmdir(path);
}

/*
 * call-seq:
 *   Dir.rmdir(dirpath) -> 0
 *
 * Removes the directory at +dirpath+ from the underlying file system:
 *
 *   Dir.rmdir('foo') # => 0
 *
 * Raises an exception if the directory is not empty.
 */
static VALUE
dir_s_rmdir(VALUE obj, VALUE dir)
{
    const char *p;
    int r;

    dir = check_dirname(dir);
    p = RSTRING_PTR(dir);
    r = IO_WITHOUT_GVL_INT(nogvl_rmdir, (void *)p);
    if (r < 0)
        rb_sys_fail_path(dir);

    return INT2FIX(0);
}

struct warning_args {
#ifdef RUBY_FUNCTION_NAME_STRING
    const char *func;
#endif
    const char *mesg;
    rb_encoding *enc;
};

#ifndef RUBY_FUNCTION_NAME_STRING
#define sys_enc_warning_in(func, mesg, enc) sys_enc_warning(mesg, enc)
#endif

static VALUE
sys_warning_1(VALUE mesg)
{
    const struct warning_args *arg = (struct warning_args *)mesg;
#ifdef RUBY_FUNCTION_NAME_STRING
    rb_sys_enc_warning(arg->enc, "%s: %s", arg->func, arg->mesg);
#else
    rb_sys_enc_warning(arg->enc, "%s", arg->mesg);
#endif
    return Qnil;
}

static void
sys_enc_warning_in(const char *func, const char *mesg, rb_encoding *enc)
{
    struct warning_args arg;
#ifdef RUBY_FUNCTION_NAME_STRING
    arg.func = func;
#endif
    arg.mesg = mesg;
    arg.enc = enc;
    rb_protect(sys_warning_1, (VALUE)&arg, 0);
}

#define GLOB_VERBOSE	(1U << (sizeof(int) * CHAR_BIT - 1))
#define sys_warning(val, enc) \
    ((flags & GLOB_VERBOSE) ? sys_enc_warning_in(RUBY_FUNCTION_NAME_STRING, (val), (enc)) :(void)0)

static inline size_t
glob_alloc_size(size_t x, size_t y)
{
    size_t z;
    if (rb_mul_size_overflow(x, y, SSIZE_MAX, &z)) {
        rb_memerror();          /* or...? */
    }
    else {
        return z;
    }
}

static inline void *
glob_alloc_n(size_t x, size_t y)
{
    return malloc(glob_alloc_size(x, y));
}

static inline void *
glob_realloc_n(void *p, size_t x, size_t y)
{
    return realloc(p, glob_alloc_size(x, y));
}

#define GLOB_ALLOC(type) ((type *)malloc(sizeof(type)))
#define GLOB_ALLOC_N(type, n) ((type *)glob_alloc_n(sizeof(type), n))
#define GLOB_REALLOC(ptr, size) realloc((ptr), (size))
#define GLOB_REALLOC_N(ptr, n) glob_realloc_n(ptr, sizeof(*(ptr)), n)
#define GLOB_FREE(ptr) free(ptr)
#define GLOB_JUMP_TAG(status) (((status) == -1) ? rb_memerror() : rb_jump_tag(status))

/*
 * ENOTDIR can be returned by stat(2) if a non-leaf element of the path
 * is not a directory.
 */
ALWAYS_INLINE(static int to_be_ignored(int e));
static inline int
to_be_ignored(int e)
{
    return e == ENOENT || e == ENOTDIR;
}

#ifdef _WIN32
#define STAT(args)	(int)(VALUE)nogvl_stat(&(args))
#define LSTAT(args)	(int)(VALUE)nogvl_lstat(&(args))
#else
#define STAT(args)	IO_WITHOUT_GVL_INT(nogvl_stat, (void *)&(args))
#define LSTAT(args)	IO_WITHOUT_GVL_INT(nogvl_lstat, (void *)&(args))
#endif

typedef int ruby_glob_errfunc(const char*, VALUE, const void*, int);
typedef struct {
    ruby_glob_func *match;
    ruby_glob_errfunc *error;
} ruby_glob_funcs_t;

static const char *
at_subpath(int fd, size_t baselen, const char *path)
{
#if USE_OPENDIR_AT
    if (fd != (int)AT_FDCWD && baselen > 0) {
        path += baselen;
        if (*path == '/') ++path;
    }
#endif
    return *path ? path : ".";
}

#if USE_OPENDIR_AT
struct fstatat_args {
    int fd;
    int flag;
    const char *path;
    struct stat *pst;
};

static void *
nogvl_fstatat(void *args)
{
    struct fstatat_args *arg = (struct fstatat_args *)args;
    return (void *)(VALUE)fstatat(arg->fd, arg->path, arg->pst, arg->flag);
}
#else
struct stat_args {
    const char *path;
    struct stat *pst;
};

static void *
nogvl_stat(void *args)
{
    struct stat_args *arg = (struct stat_args *)args;
    return (void *)(VALUE)stat(arg->path, arg->pst);
}
#endif

/* System call with warning */
static int
do_stat(int fd, const char *path, struct stat *pst, int flags, rb_encoding *enc)
{
#if USE_OPENDIR_AT
    struct fstatat_args args;
    args.fd = fd;
    args.path = path;
    args.pst = pst;
    args.flag = 0;
    int ret = IO_WITHOUT_GVL_INT(nogvl_fstatat, (void *)&args);
#else
    struct stat_args args;
    args.path = path;
    args.pst = pst;
    int ret = STAT(args);
#endif
    if (ret < 0 && !to_be_ignored(errno))
        sys_warning(path, enc);

    return ret;
}

#if defined HAVE_LSTAT || defined lstat || USE_OPENDIR_AT
#if !USE_OPENDIR_AT
static void *
nogvl_lstat(void *args)
{
    struct stat_args *arg = (struct stat_args *)args;
    return (void *)(VALUE)lstat(arg->path, arg->pst);
}
#endif

static int
do_lstat(int fd, const char *path, struct stat *pst, int flags, rb_encoding *enc)
{
#if USE_OPENDIR_AT
    struct fstatat_args args;
    args.fd = fd;
    args.path = path;
    args.pst = pst;
    args.flag = AT_SYMLINK_NOFOLLOW;
    int ret = IO_WITHOUT_GVL_INT(nogvl_fstatat, (void *)&args);
#else
    struct stat_args args;
    args.path = path;
    args.pst = pst;
    int ret = LSTAT(args);
#endif
    if (ret < 0 && !to_be_ignored(errno))
        sys_warning(path, enc);

    return ret;
}
#else
#define do_lstat do_stat
#endif

struct opendir_at_arg {
    int basefd;
    const char *path;
};

static void *
with_gvl_gc_for_fd(void *ptr)
{
    int *e = ptr;

    return (void *)RBOOL(rb_gc_for_fd(*e));
}

static int
gc_for_fd_with_gvl(int e)
{
    if (vm_initialized)
        return (int)(VALUE)rb_thread_call_with_gvl(with_gvl_gc_for_fd, &e);
    else
        return RBOOL(rb_gc_for_fd(e));
}

static void *
nogvl_opendir_at(void *ptr)
{
    const struct opendir_at_arg *oaa = ptr;
    DIR *dirp;

#if USE_OPENDIR_AT
    const int opendir_flags = (O_RDONLY|O_CLOEXEC|
#  ifdef O_DIRECTORY
                               O_DIRECTORY|
#  endif /* O_DIRECTORY */
                               0);
    int fd = openat(oaa->basefd, oaa->path, opendir_flags);

    dirp = fd >= 0 ? fdopendir(fd) : 0;
    if (!dirp) {
        int e = errno;

        switch (gc_for_fd_with_gvl(e)) {
          default:
            if (fd < 0) fd = openat(oaa->basefd, oaa->path, opendir_flags);
            if (fd >= 0) dirp = fdopendir(fd);
            if (dirp) return dirp;

            e = errno;
            /* fallthrough*/
          case 0:
            if (fd >= 0) close(fd);
            rb_errno_set(e);
        }
    }
#else  /* !USE_OPENDIR_AT */
    dirp = opendir(oaa->path);
    if (!dirp && gc_for_fd_with_gvl(errno))
        dirp = opendir(oaa->path);
#endif /* !USE_OPENDIR_AT */

    return dirp;
}

static DIR *
opendir_at(int basefd, const char *path)
{
    struct opendir_at_arg oaa;

    oaa.basefd = basefd;
    oaa.path = path;

    if (vm_initialized)
        return IO_WITHOUT_GVL(nogvl_opendir_at, &oaa);
    else
        return nogvl_opendir_at(&oaa);
}

static DIR *
do_opendir(const int basefd, size_t baselen, const char *path, int flags, rb_encoding *enc,
           ruby_glob_errfunc *errfunc, VALUE arg, int *status)
{
    DIR *dirp;
#ifdef _WIN32
    VALUE tmp = 0;
    if (!fundamental_encoding_p(enc)) {
        tmp = rb_enc_str_new(path, strlen(path), enc);
        tmp = rb_str_encode_ospath(tmp);
        path = RSTRING_PTR(tmp);
    }
#endif
    dirp = opendir_at(basefd, at_subpath(basefd, baselen, path));
    if (!dirp) {
        int e = errno;

        *status = 0;
        if (!to_be_ignored(e)) {
            if (errfunc) {
                *status = (*errfunc)(path, arg, enc, e);
            }
            else {
                sys_warning(path, enc);
            }
        }
    }
#ifdef _WIN32
    if (tmp) rb_str_resize(tmp, 0); /* GC guard */
#endif

    return dirp;
}

/* Globing pattern */
enum glob_pattern_type { PLAIN, ALPHA, BRACE, MAGICAL, RECURSIVE, MATCH_ALL, MATCH_DIR };

/* Return nonzero if S has any special globbing chars in it.  */
static enum glob_pattern_type
has_magic(const char *p, const char *pend, int flags, rb_encoding *enc)
{
    const int escape = !(flags & FNM_NOESCAPE);
    int hasalpha = 0;
    int hasmagical = 0;

    register char c;

    while (p < pend && (c = *p++) != 0) {
        switch (c) {
          case '{':
            return BRACE;

          case '*':
          case '?':
          case '[':
            hasmagical = 1;
            break;

          case '\\':
            if (escape && p++ >= pend)
                continue;
            break;

#ifdef _WIN32
          case '.':
            break;

          case '~':
            hasalpha = 1;
            break;
#endif
          default:
            if (IS_WIN32 || ISALPHA(c)) {
                hasalpha = 1;
            }
            break;
        }

        p = Next(p-1, pend, enc);
    }

    return hasmagical ? MAGICAL : hasalpha ? ALPHA : PLAIN;
}

/* Find separator in globbing pattern. */
static char *
find_dirsep(const char *p, const char *pend, int flags, rb_encoding *enc)
{
    const int escape = !(flags & FNM_NOESCAPE);

    register char c;
    int open = 0;

    while ((c = *p++) != 0) {
        switch (c) {
          case '[':
            open = 1;
            continue;
          case ']':
            open = 0;
            continue;

          case '{':
            open = 1;
            continue;
          case '}':
            open = 0;
            continue;

          case '/':
            if (!open)
                return (char *)p-1;
            continue;

          case '\\':
            if (escape && !(c = *p++))
                return (char *)p-1;
            continue;
        }

        p = Next(p-1, pend, enc);
    }

    return (char *)p-1;
}

/* Remove escaping backslashes */
static char *
remove_backslashes(char *p, register const char *pend, rb_encoding *enc)
{
    char *t = p;
    char *s = p;

    while (*p) {
        if (*p == '\\') {
            if (t != s)
                memmove(t, s, p - s);
            t += p - s;
            s = ++p;
            if (!*p) break;
        }
        Inc(p, pend, enc);
    }

    while (*p++);

    if (t != s)
        memmove(t, s, p - s); /* move '\0' too */

    return p;
}

struct glob_pattern {
    char *str;
    enum glob_pattern_type type;
    struct glob_pattern *next;
};

static void glob_free_pattern(struct glob_pattern *list);

static struct glob_pattern *
glob_make_pattern(const char *p, const char *e, int flags, rb_encoding *enc)
{
    struct glob_pattern *list, *tmp, **tail = &list;
    int dirsep = 0; /* pattern is terminated with '/' */
    int recursive = 0;

    while (p < e && *p) {
        tmp = GLOB_ALLOC(struct glob_pattern);
        if (!tmp) goto error;
        if (p + 2 < e && p[0] == '*' && p[1] == '*' && p[2] == '/') {
            /* fold continuous RECURSIVEs (needed in glob_helper) */
            do { p += 3; while (*p == '/') p++; } while (p[0] == '*' && p[1] == '*' && p[2] == '/');
            tmp->type = RECURSIVE;
            tmp->str = 0;
            dirsep = 1;
            recursive = 1;
        }
        else {
            const char *m = find_dirsep(p, e, flags, enc);
            const enum glob_pattern_type magic = has_magic(p, m, flags, enc);
            const enum glob_pattern_type non_magic = (USE_NAME_ON_FS || FNM_SYSCASE) ? PLAIN : ALPHA;
            char *buf;

            if (!(FNM_SYSCASE || magic > non_magic) && !recursive && *m) {
                const char *m2;
                while (has_magic(m+1, m2 = find_dirsep(m+1, e, flags, enc), flags, enc) <= non_magic &&
                       *m2) {
                    m = m2;
                }
            }
            buf = GLOB_ALLOC_N(char, m-p+1);
            if (!buf) {
                GLOB_FREE(tmp);
                goto error;
            }
            memcpy(buf, p, m-p);
            buf[m-p] = '\0';
            tmp->type = magic > MAGICAL ? MAGICAL : magic > non_magic ? magic : PLAIN;
            tmp->str = buf;
            if (*m) {
                dirsep = 1;
                p = m + 1;
            }
            else {
                dirsep = 0;
                p = m;
            }
        }
        *tail = tmp;
        tail = &tmp->next;
    }

    tmp = GLOB_ALLOC(struct glob_pattern);
    if (!tmp) {
        goto error;
    }
    tmp->type = dirsep ? MATCH_DIR : MATCH_ALL;
    tmp->str = 0;
    *tail = tmp;
    tmp->next = 0;

    return list;

  error:
    *tail = 0;
    glob_free_pattern(list);
    return 0;
}

static void
glob_free_pattern(struct glob_pattern *list)
{
    while (list) {
        struct glob_pattern *tmp = list;
        list = list->next;
        if (tmp->str)
            GLOB_FREE(tmp->str);
        GLOB_FREE(tmp);
    }
}

static char *
join_path(const char *path, size_t len, int dirsep, const char *name, size_t namlen)
{
    char *buf = GLOB_ALLOC_N(char, len+namlen+(dirsep?1:0)+1);

    if (!buf) return 0;
    memcpy(buf, path, len);
    if (dirsep) {
        buf[len++] = '/';
    }
    memcpy(buf+len, name, namlen);
    buf[len+namlen] = '\0';
    return buf;
}

#ifdef HAVE_GETATTRLIST
# if defined HAVE_FGETATTRLIST
#   define is_case_sensitive(dirp, path) is_case_sensitive(dirp)
# else
#   define is_case_sensitive(dirp, path) is_case_sensitive(path)
# endif
static int
is_case_sensitive(DIR *dirp, const char *path)
{
    struct {
        u_int32_t length;
        vol_capabilities_attr_t cap[1];
    } __attribute__((aligned(4), packed)) attrbuf[1];
    struct attrlist al = {ATTR_BIT_MAP_COUNT, 0, 0, ATTR_VOL_INFO|ATTR_VOL_CAPABILITIES};
    const vol_capabilities_attr_t *const cap = attrbuf[0].cap;
    const int idx = VOL_CAPABILITIES_FORMAT;
    const uint32_t mask = VOL_CAP_FMT_CASE_SENSITIVE;
    struct getattrlist_args args = GETATTRLIST_ARGS(&al, attrbuf, FSOPT_NOFOLLOW);
#   if defined HAVE_FGETATTRLIST
    int ret = gvl_fgetattrlist(&args, dirfd(dirp));
#   else
    int ret = gvl_getattrlist(&args, path);
#   endif
    if (ret)
        return -1;

    if (!(cap->valid[idx] & mask))
        return -1;
    return (cap->capabilities[idx] & mask) != 0;
}

static char *
replace_real_basename(char *path, long base, rb_encoding *enc, int norm_p, int flags, rb_pathtype_t *type)
{
    struct {
        u_int32_t length;
        attrreference_t ref[1];
        fsobj_type_t objtype;
        char path[MAXPATHLEN * 3];
    } __attribute__((aligned(4), packed)) attrbuf[1];
    struct attrlist al = {ATTR_BIT_MAP_COUNT, 0, ATTR_CMN_NAME|ATTR_CMN_OBJTYPE};
    const attrreference_t *const ar = attrbuf[0].ref;
    const char *name;
    long len;
    char *tmp;
    IF_NORMALIZE_UTF8PATH(VALUE utf8str = Qnil);

    *type = path_noent;
    struct getattrlist_args args = GETATTRLIST_ARGS(&al, attrbuf, FSOPT_NOFOLLOW);
    if (gvl_getattrlist(&args, path)) {
        if (!to_be_ignored(errno))
            sys_warning(path, enc);
        return path;
    }

    switch (attrbuf[0].objtype) {
      case VREG: *type = path_regular; break;
      case VDIR: *type = path_directory; break;
      case VLNK: *type = path_symlink; break;
      default: *type = path_exist; break;
    }
    name = (char *)ar + ar->attr_dataoffset;
    len = (long)ar->attr_length - 1;
    if (name + len > (char *)attrbuf + sizeof(attrbuf))
        return path;

# if NORMALIZE_UTF8PATH
    if (norm_p && has_nonascii(name, len)) {
        if (!NIL_P(utf8str = rb_str_normalize_ospath(name, len))) {
            RSTRING_GETMEM(utf8str, name, len);
        }
    }
# endif

    tmp = GLOB_REALLOC(path, base + len + 1);
    if (tmp) {
        path = tmp;
        memcpy(path + base, name, len);
        path[base + len] = '\0';
    }
    IF_NORMALIZE_UTF8PATH(if (!NIL_P(utf8str)) rb_str_resize(utf8str, 0));
    return path;
}
#elif defined _WIN32
VALUE rb_w32_conv_from_wchar(const WCHAR *wstr, rb_encoding *enc);
int rb_w32_reparse_symlink_p(const WCHAR *path);

static char *
replace_real_basename(char *path, long base, rb_encoding *enc, int norm_p, int flags, rb_pathtype_t *type)
{
    char *plainname = path;
    volatile VALUE tmp = 0;
    WIN32_FIND_DATAW fd;
    WIN32_FILE_ATTRIBUTE_DATA fa;
    WCHAR *wplain;
    HANDLE h = INVALID_HANDLE_VALUE;
    long wlen;
    int e = 0;
    if (!fundamental_encoding_p(enc)) {
        tmp = rb_enc_str_new_cstr(plainname, enc);
        tmp = rb_str_encode_ospath(tmp);
        plainname = RSTRING_PTR(tmp);
    }
    wplain = rb_w32_mbstr_to_wstr(CP_UTF8, plainname, -1, &wlen);
    if (tmp) rb_str_resize(tmp, 0);
    if (!wplain) return path;
    if (GetFileAttributesExW(wplain, GetFileExInfoStandard, &fa)) {
        h = FindFirstFileW(wplain, &fd);
        e = rb_w32_map_errno(GetLastError());
    }
    if (fa.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
        if (!rb_w32_reparse_symlink_p(wplain))
            fa.dwFileAttributes &= ~FILE_ATTRIBUTE_REPARSE_POINT;
    }
    free(wplain);
    if (h == INVALID_HANDLE_VALUE) {
        *type = path_noent;
        if (e && !to_be_ignored(e)) {
            errno = e;
            sys_warning(path, enc);
        }
        return path;
    }
    FindClose(h);
    *type =
        (fa.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) ? path_symlink :
        (fa.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ? path_directory :
        path_regular;
    if (tmp) {
        char *buf;
        tmp = rb_w32_conv_from_wchar(fd.cFileName, enc);
        wlen = RSTRING_LEN(tmp);
        buf = GLOB_REALLOC(path, base + wlen + 1);
        if (buf) {
            path = buf;
            memcpy(path + base, RSTRING_PTR(tmp), wlen);
            path[base + wlen] = 0;
        }
        rb_str_resize(tmp, 0);
    }
    else {
        char *utf8filename;
        wlen = WideCharToMultiByte(CP_UTF8, 0, fd.cFileName, -1, NULL, 0, NULL, NULL);
        utf8filename = GLOB_REALLOC(0, wlen);
        if (utf8filename) {
            char *buf;
            WideCharToMultiByte(CP_UTF8, 0, fd.cFileName, -1, utf8filename, wlen, NULL, NULL);
            buf = GLOB_REALLOC(path, base + wlen + 1);
            if (buf) {
                path = buf;
                memcpy(path + base, utf8filename, wlen);
                path[base + wlen] = 0;
            }
            GLOB_FREE(utf8filename);
        }
    }
    return path;
}
#elif USE_NAME_ON_FS == USE_NAME_ON_FS_REAL_BASENAME
# error not implemented
#endif

#ifndef S_ISDIR
#   define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif

#ifndef S_ISLNK
#  ifndef S_IFLNK
#    define S_ISLNK(m) (0)
#  else
#    define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
#  endif
#endif

struct glob_args {
    void (*func)(const char *, VALUE, void *);
    const char *path;
    const char *base;
    size_t baselen;
    VALUE value;
    rb_encoding *enc;
};

#define glob_call_func(func, path, arg, enc) (*(func))((path), (arg), (void *)(enc))

static VALUE
glob_func_caller(VALUE val)
{
    struct glob_args *args = (struct glob_args *)val;

    glob_call_func(args->func, args->path, args->value, args->enc);
    return Qnil;
}

struct glob_error_args {
    const char *path;
    rb_encoding *enc;
    int error;
};

static VALUE
glob_func_warning(VALUE val)
{
    struct glob_error_args *arg = (struct glob_error_args *)val;
    rb_syserr_enc_warning(arg->error, arg->enc, "%s", arg->path);
    return Qnil;
}

#if 0
static int
rb_glob_warning(const char *path, VALUE a, const void *enc, int error)
{
    int status;
    struct glob_error_args args;

    args.path = path;
    args.enc = enc;
    args.error = error;
    rb_protect(glob_func_warning, (VALUE)&args, &status);
    return status;
}
#endif

NORETURN(static VALUE glob_func_error(VALUE val));

static VALUE
glob_func_error(VALUE val)
{
    struct glob_error_args *arg = (struct glob_error_args *)val;
    VALUE path = rb_enc_str_new_cstr(arg->path, arg->enc);
    rb_syserr_fail_str(arg->error, path);
    UNREACHABLE_RETURN(Qnil);
}

static int
rb_glob_error(const char *path, VALUE a, const void *enc, int error)
{
    int status;
    struct glob_error_args args;
    VALUE (*errfunc)(VALUE) = glob_func_error;

    switch (error) {
      case EACCES:
#ifdef ENOTCAPABLE
      case ENOTCAPABLE:
#endif
        errfunc = glob_func_warning;
    }
    args.path = path;
    args.enc = enc;
    args.error = error;
    rb_protect(errfunc, (VALUE)&args, &status);
    return status;
}

typedef struct rb_dirent {
    long d_namlen;
    const char *d_name;
#ifdef _WIN32
    const char *d_altname;
#endif
    uint8_t d_type;
} rb_dirent_t;

static inline int
dirent_match(const char *pat, rb_encoding *enc, const char *name, const rb_dirent_t *dp, int flags)
{
    if (fnmatch(pat, enc, name, flags) == 0) return 1;
#ifdef _WIN32
    if (dp->d_altname && (flags & FNM_SHORTNAME)) {
        if (fnmatch(pat, enc, dp->d_altname, flags) == 0) return 1;
    }
#endif
    return 0;
}

struct push_glob_args {
    int fd;
    const char *path;
    size_t baselen;
    size_t namelen;
    int dirsep; /* '/' should be placed before appending child entry's name to 'path'. */
    rb_pathtype_t pathtype; /* type of 'path' */
    int flags;
    const ruby_glob_funcs_t *funcs;
    VALUE arg;
};

struct dirent_brace_args {
    const char *name;
    const rb_dirent_t *dp;
    int flags;
};

static int
dirent_match_brace(const char *pattern, VALUE val, void *enc)
{
    struct dirent_brace_args *arg = (struct dirent_brace_args *)val;

    return dirent_match(pattern, enc, arg->name, arg->dp, arg->flags);
}

/* join paths from pattern list of glob_make_pattern() */
static char*
join_path_from_pattern(struct glob_pattern **beg)
{
    struct glob_pattern *p;
    char *path = NULL;
    size_t path_len = 0;

    for (p = *beg; p; p = p->next) {
        const char *str;
        switch (p->type) {
          case RECURSIVE:
            str = "**";
            break;
          case MATCH_DIR:
            /* append last slash */
            str = "";
            break;
          default:
            str = p->str;
            if (!str) continue;
        }
        if (!path) {
            path_len = strlen(str);
            path = GLOB_ALLOC_N(char, path_len + 1);
            if (path) {
                memcpy(path, str, path_len);
                path[path_len] = '\0';
            }
        }
        else {
            size_t len = strlen(str);
            char *tmp;
            tmp = GLOB_REALLOC(path, path_len + len + 2);
            if (tmp) {
                path = tmp;
                path[path_len++] = '/';
                memcpy(path + path_len, str, len);
                path_len += len;
                path[path_len] = '\0';
            }
        }
    }
    return path;
}

static int push_caller(const char *path, VALUE val, void *enc);

static int ruby_brace_expand(const char *str, int flags, ruby_glob_func *func, VALUE arg,
                             rb_encoding *enc, VALUE var);

static const size_t rb_dirent_name_offset =
    offsetof(rb_dirent_t, d_type) + sizeof(uint8_t);

static rb_dirent_t *
dirent_copy(const struct dirent *dp, rb_dirent_t *rdp)
{
    if (!dp) return NULL;
    size_t namlen = NAMLEN(dp);
    const size_t altlen =
#ifdef _WIN32
        dp->d_altlen ? dp->d_altlen + 1 :
#endif
        0;
    rb_dirent_t *newrdp = rdp;
    if (!rdp && !(newrdp = malloc(rb_dirent_name_offset + namlen + 1 + altlen)))
        return NULL;
    newrdp->d_namlen = namlen;
    if (!rdp) {
        char *name = (char *)newrdp + rb_dirent_name_offset;
        memcpy(name, dp->d_name, namlen);
        name[namlen] = '\0';
#ifdef _WIN32
        newrdp->d_altname = NULL;
        if (altlen) {
            char *const altname = name + namlen + 1;
            memcpy(altname, dp->d_altname, altlen - 1);
            altname[altlen - 1] = '\0';
            newrdp->d_altname = altname;
        }
#endif
        newrdp->d_name = name;
    }
    else {
        newrdp->d_name = dp->d_name;
#ifdef _WIN32
        newrdp->d_altname = dp->d_altname;
#endif
    }
#if !EMULATE_IFTODT
    newrdp->d_type = dp->d_type;
#else
    newrdp->d_type = 0;
#endif
    return newrdp;
}

typedef union {
    struct {
        DIR *dirp;
        rb_dirent_t ent;
    } nosort;
    struct {
        size_t count, idx;
        rb_dirent_t **entries;
    } sort;
} ruby_glob_entries_t;

static int
glob_sort_cmp(const void *a, const void *b, void *e)
{
    const rb_dirent_t *ent1 = *(void **)a;
    const rb_dirent_t *ent2 = *(void **)b;
    return strcmp(ent1->d_name, ent2->d_name);
}

static void
glob_dir_finish(ruby_glob_entries_t *ent, int flags)
{
    if (flags & FNM_GLOB_NOSORT) {
        check_closedir(ent->nosort.dirp);
        ent->nosort.dirp = NULL;
    }
    else if (ent->sort.entries) {
        for (size_t i = 0, count = ent->sort.count; i < count;) {
            GLOB_FREE(ent->sort.entries[i++]);
        }
        GLOB_FREE(ent->sort.entries);
        ent->sort.entries = NULL;
        ent->sort.count = ent->sort.idx = 0;
    }
}

static ruby_glob_entries_t *
glob_opendir(ruby_glob_entries_t *ent, DIR *dirp, int flags, rb_encoding *enc)
{
    MEMZERO(ent, ruby_glob_entries_t, 1);
    if (flags & FNM_GLOB_NOSORT) {
        ent->nosort.dirp = dirp;
        return ent;
    }
    else {
        void *newp;
        struct dirent *dp;
        size_t count = 0, capacity = 0;
        ent->sort.count = 0;
        ent->sort.idx = 0;
        ent->sort.entries = 0;
#ifdef _WIN32
        if ((capacity = dirp->nfiles) > 0) {
            if (!(newp = GLOB_ALLOC_N(rb_dirent_t, capacity))) {
                check_closedir(dirp);
                return NULL;
            }
            ent->sort.entries = newp;
        }
#endif
        while ((dp = READDIR(dirp, enc)) != NULL) {
            rb_dirent_t *rdp = dirent_copy(dp, NULL);
            if (!rdp) {
                goto nomem;
            }
            if (count >= capacity) {
                capacity += 256;
                if (!(newp = GLOB_REALLOC_N(ent->sort.entries, capacity)))
                    goto nomem;
                ent->sort.entries = newp;
            }
            ent->sort.entries[count++] = rdp;
            ent->sort.count = count;
        }
        check_closedir(dirp);
        if (count < capacity) {
            if (!(newp = GLOB_REALLOC_N(ent->sort.entries, count))) {
                glob_dir_finish(ent, 0);
                return NULL;
            }
            ent->sort.entries = newp;
        }
        ruby_qsort(ent->sort.entries, ent->sort.count, sizeof(ent->sort.entries[0]),
                   glob_sort_cmp, NULL);
        return ent;
    }

  nomem:
    glob_dir_finish(ent, 0);
    check_closedir(dirp);
    return NULL;
}

static rb_dirent_t *
glob_getent(ruby_glob_entries_t *ent, int flags, rb_encoding *enc)
{
    if (flags & FNM_GLOB_NOSORT) {
        return dirent_copy(READDIR(ent->nosort.dirp, enc), &ent->nosort.ent);
    }
    else if (ent->sort.idx < ent->sort.count) {
        return ent->sort.entries[ent->sort.idx++];
    }
    else {
        return NULL;
    }
}

static int
glob_helper(
    int fd,
    const char *path,
    size_t baselen,
    size_t namelen,
    int dirsep, /* '/' should be placed before appending child entry's name to 'path'. */
    rb_pathtype_t pathtype, /* type of 'path' */
    struct glob_pattern **beg,
    struct glob_pattern **end,
    int flags,
    const ruby_glob_funcs_t *funcs,
    VALUE arg,
    rb_encoding *enc)
{
    struct stat st;
    int status = 0;
    struct glob_pattern **cur, **new_beg, **new_end;
    int plain = 0, brace = 0, magical = 0, recursive = 0, match_all = 0, match_dir = 0;
    int escape = !(flags & FNM_NOESCAPE);
    size_t pathlen = baselen + namelen;

    rb_check_stack_overflow();

    for (cur = beg; cur < end; ++cur) {
        struct glob_pattern *p = *cur;
        if (p->type == RECURSIVE) {
            recursive = 1;
            p = p->next;
        }
        switch (p->type) {
          case PLAIN:
            plain = 1;
            break;
          case ALPHA:
#if USE_NAME_ON_FS == USE_NAME_ON_FS_REAL_BASENAME
            plain = 1;
#else
            magical = 1;
#endif
            break;
          case BRACE:
            if (!recursive || strchr(p->str, '/')) {
                brace = 1;
            }
            break;
          case MAGICAL:
            magical = 2;
            break;
          case MATCH_ALL:
            match_all = 1;
            break;
          case MATCH_DIR:
            match_dir = 1;
            break;
          case RECURSIVE:
            rb_bug("continuous RECURSIVEs");
        }
    }

    if (brace) {
        struct push_glob_args args;
        char* brace_path = join_path_from_pattern(beg);
        if (!brace_path) return -1;
        args.fd = fd;
        args.path = path;
        args.baselen = baselen;
        args.namelen = namelen;
        args.dirsep = dirsep;
        args.pathtype = pathtype;
        args.flags = flags;
        args.funcs = funcs;
        args.arg = arg;
        status = ruby_brace_expand(brace_path, flags, push_caller, (VALUE)&args, enc, Qfalse);
        GLOB_FREE(brace_path);
        return status;
    }

    if (*path) {
        if (match_all && pathtype == path_unknown) {
            if (do_lstat(fd, path, &st, flags, enc) == 0) {
                pathtype = IFTODT(st.st_mode);
            }
            else {
                pathtype = path_noent;
            }
        }
        if (match_dir && (pathtype == path_unknown || pathtype == path_symlink)) {
            if (do_stat(fd, path, &st, flags, enc) == 0) {
                pathtype = IFTODT(st.st_mode);
            }
            else {
                pathtype = path_noent;
            }
        }
        if (match_all && pathtype > path_noent) {
            const char *subpath = path + baselen + (baselen && path[baselen] == '/');
            status = glob_call_func(funcs->match, subpath, arg, enc);
            if (status) return status;
        }
        if (match_dir && pathtype == path_directory) {
            int seplen = (baselen && path[baselen] == '/');
            const char *subpath = path + baselen + seplen;
            char *tmp = join_path(subpath, namelen - seplen, dirsep, "", 0);
            if (!tmp) return -1;
            status = glob_call_func(funcs->match, tmp, arg, enc);
            GLOB_FREE(tmp);
            if (status) return status;
        }
    }

    if (pathtype == path_noent) return 0;

    if (magical || recursive) {
        rb_dirent_t *dp;
        DIR *dirp;
# if USE_NAME_ON_FS == USE_NAME_ON_FS_BY_FNMATCH
        char *plainname = 0;
# endif
        IF_NORMALIZE_UTF8PATH(int norm_p);
# if USE_NAME_ON_FS == USE_NAME_ON_FS_BY_FNMATCH
        if (cur + 1 == end && (*cur)->type <= ALPHA) {
            plainname = join_path(path, pathlen, dirsep, (*cur)->str, strlen((*cur)->str));
            if (!plainname) return -1;
            dirp = do_opendir(fd, basename, plainname, flags, enc, funcs->error, arg, &status);
            GLOB_FREE(plainname);
        }
        else
# else
            ;
# endif
        dirp = do_opendir(fd, baselen, path, flags, enc, funcs->error, arg, &status);
        if (dirp == NULL) {
# if FNM_SYSCASE || NORMALIZE_UTF8PATH
            if ((magical < 2) && !recursive && (errno == EACCES)) {
                /* no read permission, fallback */
                goto literally;
            }
# endif
            return status;
        }
        IF_NORMALIZE_UTF8PATH(norm_p = need_normalization(dirp, *path ? path : "."));

# if NORMALIZE_UTF8PATH
        if (!(norm_p || magical || recursive)) {
            check_closedir(dirp);
            goto literally;
        }
# endif
# ifdef HAVE_GETATTRLIST
        if (is_case_sensitive(dirp, path) == 0)
            flags |= FNM_CASEFOLD;
# endif
        ruby_glob_entries_t globent;
        if (!glob_opendir(&globent, dirp, flags, enc)) {
            status = 0;
            if (funcs->error) {
                status = (*funcs->error)(path, arg, enc, ENOMEM);
            }
            else {
                sys_warning(path, enc);
            }
            return status;
        }

        int skipdot = (flags & FNM_GLOB_SKIPDOT);
        flags |= FNM_GLOB_SKIPDOT;

        while ((dp = glob_getent(&globent, flags, enc)) != NULL) {
            char *buf;
            rb_pathtype_t new_pathtype = path_unknown;
            const char *name;
            size_t namlen;
            int dotfile = 0;
            IF_NORMALIZE_UTF8PATH(VALUE utf8str = Qnil);

            name = dp->d_name;
            namlen = dp->d_namlen;
            if (name[0] == '.') {
                ++dotfile;
                if (namlen == 1) {
                    /* unless DOTMATCH, skip current directories not to recurse infinitely */
                    if (recursive && !(flags & FNM_DOTMATCH)) continue;
                    if (skipdot) continue;
                    ++dotfile;
                    new_pathtype = path_directory; /* force to skip stat/lstat */
                }
                else if (namlen == 2 && name[1] == '.') {
                    /* always skip parent directories not to recurse infinitely */
                    continue;
                }
            }

# if NORMALIZE_UTF8PATH
            if (norm_p && has_nonascii(name, namlen)) {
                if (!NIL_P(utf8str = rb_str_normalize_ospath(name, namlen))) {
                    RSTRING_GETMEM(utf8str, name, namlen);
                }
            }
# endif
            buf = join_path(path, pathlen, dirsep, name, namlen);
            IF_NORMALIZE_UTF8PATH(if (!NIL_P(utf8str)) rb_str_resize(utf8str, 0));
            if (!buf) {
                status = -1;
                break;
            }
            name = buf + pathlen + (dirsep != 0);
#if !EMULATE_IFTODT
            if (dp->d_type != DT_UNKNOWN) {
                /* Got it. We need no more lstat. */
                new_pathtype = dp->d_type;
            }
#endif
            if (recursive && dotfile < ((flags & FNM_DOTMATCH) ? 2 : 1) &&
                new_pathtype == path_unknown) {
                /* RECURSIVE never match dot files unless FNM_DOTMATCH is set */
                if (do_lstat(fd, buf, &st, flags, enc) == 0)
                    new_pathtype = IFTODT(st.st_mode);
                else
                    new_pathtype = path_noent;
            }

            new_beg = new_end = GLOB_ALLOC_N(struct glob_pattern *, (end - beg) * 2);
            if (!new_beg) {
                GLOB_FREE(buf);
                status = -1;
                break;
            }

            for (cur = beg; cur < end; ++cur) {
                struct glob_pattern *p = *cur;
                struct dirent_brace_args args;
                if (p->type == RECURSIVE) {
                    if (new_pathtype == path_directory || /* not symlink but real directory */
                        new_pathtype == path_exist) {
                        if (dotfile < ((flags & FNM_DOTMATCH) ? 2 : 1))
                            *new_end++ = p; /* append recursive pattern */
                    }
                    p = p->next; /* 0 times recursion */
                }
                switch (p->type) {
                  case BRACE:
                    args.name = name;
                    args.dp = dp;
                    args.flags = flags;
                    if (ruby_brace_expand(p->str, flags, dirent_match_brace,
                                          (VALUE)&args, enc, Qfalse) > 0)
                        *new_end++ = p->next;
                    break;
                  case ALPHA:
# if USE_NAME_ON_FS == USE_NAME_ON_FS_BY_FNMATCH
                    if (plainname) {
                        *new_end++ = p->next;
                        break;
                    }
# endif
                  case PLAIN:
                  case MAGICAL:
                    if (dirent_match(p->str, enc, name, dp, flags))
                        *new_end++ = p->next;
                  default:
                    break;
                }
            }

            status = glob_helper(fd, buf, baselen, name - buf - baselen + namlen, 1,
                                 new_pathtype, new_beg, new_end,
                                 flags, funcs, arg, enc);
            GLOB_FREE(buf);
            GLOB_FREE(new_beg);
            if (status) break;
        }

        glob_dir_finish(&globent, flags);
    }
    else if (plain) {
        struct glob_pattern **copy_beg, **copy_end, **cur2;

# if FNM_SYSCASE || NORMALIZE_UTF8PATH
      literally:
# endif
        copy_beg = copy_end = GLOB_ALLOC_N(struct glob_pattern *, end - beg);
        if (!copy_beg) return -1;
        for (cur = beg; cur < end; ++cur)
            *copy_end++ = (*cur)->type <= ALPHA ? *cur : 0;

        for (cur = copy_beg; cur < copy_end; ++cur) {
            if (*cur) {
                rb_pathtype_t new_pathtype = path_unknown;
                char *buf;
                char *name;
                size_t len = strlen((*cur)->str) + 1;
                name = GLOB_ALLOC_N(char, len);
                if (!name) {
                    status = -1;
                    break;
                }
                memcpy(name, (*cur)->str, len);
                if (escape)
                    len = remove_backslashes(name, name+len-1, enc) - name;

                new_beg = new_end = GLOB_ALLOC_N(struct glob_pattern *, end - beg);
                if (!new_beg) {
                    GLOB_FREE(name);
                    status = -1;
                    break;
                }
                *new_end++ = (*cur)->next;
                for (cur2 = cur + 1; cur2 < copy_end; ++cur2) {
                    if (*cur2 && fnmatch((*cur2)->str, enc, name, flags) == 0) {
                        *new_end++ = (*cur2)->next;
                        *cur2 = 0;
                    }
                }

                buf = join_path(path, pathlen, dirsep, name, len);
                GLOB_FREE(name);
                if (!buf) {
                    GLOB_FREE(new_beg);
                    status = -1;
                    break;
                }
#if USE_NAME_ON_FS == USE_NAME_ON_FS_REAL_BASENAME
                if ((*cur)->type == ALPHA) {
                    buf = replace_real_basename(buf, pathlen + (dirsep != 0), enc,
                                                IF_NORMALIZE_UTF8PATH(1)+0,
                                                flags, &new_pathtype);
                    if (!buf) break;
                }
#endif
                status = glob_helper(fd, buf, baselen,
                                     namelen + strlen(buf + pathlen), 1,
                                     new_pathtype, new_beg, new_end,
                                     flags, funcs, arg, enc);
                GLOB_FREE(buf);
                GLOB_FREE(new_beg);
                if (status) break;
            }
        }

        GLOB_FREE(copy_beg);
    }

    return status;
}

static int
push_caller(const char *path, VALUE val, void *enc)
{
    struct push_glob_args *arg = (struct push_glob_args *)val;
    struct glob_pattern *list;
    int status;

    list = glob_make_pattern(path, path + strlen(path), arg->flags, enc);
    if (!list) {
        return -1;
    }
    status = glob_helper(arg->fd, arg->path, arg->baselen, arg->namelen, arg->dirsep,
                         arg->pathtype, &list, &list + 1, arg->flags, arg->funcs,
                         arg->arg, enc);
    glob_free_pattern(list);
    return status;
}

static int ruby_glob0(const char *path, int fd, const char *base, int flags,
                      const ruby_glob_funcs_t *funcs, VALUE arg, rb_encoding *enc);

struct push_glob0_args {
    int fd;
    const char *base;
    int flags;
    const ruby_glob_funcs_t *funcs;
    VALUE arg;
};

static int
push_glob0_caller(const char *path, VALUE val, void *enc)
{
    struct push_glob0_args *arg = (struct push_glob0_args *)val;
    return ruby_glob0(path, arg->fd, arg->base, arg->flags, arg->funcs, arg->arg, enc);
}

static int
ruby_glob0(const char *path, int fd, const char *base, int flags,
           const ruby_glob_funcs_t *funcs, VALUE arg,
           rb_encoding *enc)
{
    struct glob_pattern *list;
    const char *root, *start;
    char *buf;
    size_t n, baselen = 0;
    int status, dirsep = FALSE;

    start = root = path;

    if (*root == '{') {
        struct push_glob0_args args;
        args.fd = fd;
        args.base = base;
        args.flags = flags;
        args.funcs = funcs;
        args.arg = arg;
        return ruby_brace_expand(path, flags, push_glob0_caller, (VALUE)&args, enc, Qfalse);
    }

    flags |= FNM_SYSCASE;
#if defined DOSISH
    root = rb_enc_path_skip_prefix(root, root + strlen(root), enc);
#endif

    if (*root == '/') root++;

    n = root - start;
    if (!n && base) {
        n = strlen(base);
        baselen = n;
        start = base;
        dirsep = TRUE;
    }
    buf = GLOB_ALLOC_N(char, n + 1);
    if (!buf) return -1;
    MEMCPY(buf, start, char, n);
    buf[n] = '\0';

    list = glob_make_pattern(root, root + strlen(root), flags, enc);
    if (!list) {
        GLOB_FREE(buf);
        return -1;
    }
    status = glob_helper(fd, buf, baselen, n-baselen, dirsep,
                         path_unknown, &list, &list + 1,
                         flags, funcs, arg, enc);
    glob_free_pattern(list);
    GLOB_FREE(buf);

    return status;
}

int
ruby_glob(const char *path, int flags, ruby_glob_func *func, VALUE arg)
{
    ruby_glob_funcs_t funcs;
    funcs.match = func;
    funcs.error = 0;
    return ruby_glob0(path, AT_FDCWD, 0, flags & ~GLOB_VERBOSE,
                      &funcs, arg, rb_ascii8bit_encoding());
}

static int
rb_glob_caller(const char *path, VALUE a, void *enc)
{
    int status;
    struct glob_args *args = (struct glob_args *)a;

    args->path = path;
    rb_protect(glob_func_caller, a, &status);
    return status;
}

static const ruby_glob_funcs_t rb_glob_funcs = {
    rb_glob_caller, rb_glob_error,
};

void
rb_glob(const char *path, void (*func)(const char *, VALUE, void *), VALUE arg)
{
    struct glob_args args;
    int status;

    args.func = func;
    args.value = arg;
    args.enc = rb_ascii8bit_encoding();

    status = ruby_glob0(path, AT_FDCWD, 0, GLOB_VERBOSE, &rb_glob_funcs,
                        (VALUE)&args, args.enc);
    if (status) GLOB_JUMP_TAG(status);
}

static void
push_pattern(const char *path, VALUE ary, void *enc)
{
#if defined _WIN32 || defined __APPLE__
    VALUE name = rb_utf8_str_new_cstr(path);
    rb_encoding *eenc = rb_default_internal_encoding();
    name = rb_str_conv_enc(name, NULL, eenc ? eenc : enc);
#else
    VALUE name = rb_external_str_new_with_enc(path, strlen(path), enc);
#endif
    rb_ary_push(ary, name);
}

static int
ruby_brace_expand(const char *str, int flags, ruby_glob_func *func, VALUE arg,
                  rb_encoding *enc, VALUE var)
{
    const int escape = !(flags & FNM_NOESCAPE);
    const char *p = str;
    const char *pend = p + strlen(p);
    const char *s = p;
    const char *lbrace = 0, *rbrace = 0;
    int nest = 0, status = 0;

    while (*p) {
        if (*p == '{' && nest++ == 0) {
            lbrace = p;
        }
        if (*p == '}' && lbrace && --nest == 0) {
            rbrace = p;
            break;
        }
        if (*p == '\\' && escape) {
            if (!*++p) break;
        }
        Inc(p, pend, enc);
    }

    if (lbrace && rbrace) {
        size_t len = strlen(s) + 1;
        char *buf = GLOB_ALLOC_N(char, len);
        long shift;

        if (!buf) return -1;
        memcpy(buf, s, lbrace-s);
        shift = (lbrace-s);
        p = lbrace;
        while (p < rbrace) {
            const char *t = ++p;
            nest = 0;
            while (p < rbrace && !(*p == ',' && nest == 0)) {
                if (*p == '{') nest++;
                if (*p == '}') nest--;
                if (*p == '\\' && escape) {
                    if (++p == rbrace) break;
                }
                Inc(p, pend, enc);
            }
            memcpy(buf+shift, t, p-t);
            strlcpy(buf+shift+(p-t), rbrace+1, len-(shift+(p-t)));
            status = ruby_brace_expand(buf, flags, func, arg, enc, var);
            if (status) break;
        }
        GLOB_FREE(buf);
    }
    else if (!lbrace && !rbrace) {
        status = glob_call_func(func, s, arg, enc);
    }

    RB_GC_GUARD(var);
    return status;
}

struct brace_args {
    ruby_glob_funcs_t funcs;
    VALUE value;
    int flags;
};

static int
glob_brace(const char *path, VALUE val, void *enc)
{
    struct brace_args *arg = (struct brace_args *)val;

    return ruby_glob0(path, AT_FDCWD, 0, arg->flags, &arg->funcs, arg->value, enc);
}

int
ruby_brace_glob_with_enc(const char *str, int flags, ruby_glob_func *func, VALUE arg, rb_encoding *enc)
{
    struct brace_args args;

    flags &= ~GLOB_VERBOSE;
    args.funcs.match = func;
    args.funcs.error = 0;
    args.value = arg;
    args.flags = flags;
    return ruby_brace_expand(str, flags, glob_brace, (VALUE)&args, enc, Qfalse);
}

int
ruby_brace_glob(const char *str, int flags, ruby_glob_func *func, VALUE arg)
{
    return ruby_brace_glob_with_enc(str, flags, func, arg, rb_ascii8bit_encoding());
}

static int
push_glob(VALUE ary, VALUE str, VALUE base, int flags)
{
    struct glob_args args;
    int fd;
    rb_encoding *enc = rb_enc_get(str);

#if defined _WIN32 || defined __APPLE__
    str = rb_str_encode_ospath(str);
#endif
    if (rb_enc_to_index(enc) == ENCINDEX_US_ASCII)
        enc = rb_filesystem_encoding();
    if (rb_enc_to_index(enc) == ENCINDEX_US_ASCII)
        enc = rb_ascii8bit_encoding();
    flags |= GLOB_VERBOSE;
    args.func = push_pattern;
    args.value = ary;
    args.enc = enc;
    args.base = 0;
    fd = AT_FDCWD;
    if (!NIL_P(base)) {
        if (!RB_TYPE_P(base, T_STRING) || !rb_enc_check(str, base)) {
            struct dir_data *dirp = RTYPEDDATA_GET_DATA(base);
            if (!dirp->dir) dir_closed();
#ifdef HAVE_DIRFD
            if ((fd = dirfd(dirp->dir)) == -1)
                rb_sys_fail_path(dir_inspect(base));
#endif
            base = dirp->path;
        }
        args.base = RSTRING_PTR(base);
    }
#if defined _WIN32 || defined __APPLE__
    enc = rb_utf8_encoding();
#endif

    return ruby_glob0(RSTRING_PTR(str), fd, args.base, flags, &rb_glob_funcs,
                      (VALUE)&args, enc);
}

static VALUE
rb_push_glob(VALUE str, VALUE base, int flags) /* '\0' is delimiter */
{
    VALUE ary;
    int status;

    /* can contain null bytes as separators */
    if (!RB_TYPE_P(str, T_STRING)) {
        FilePathValue(str);
    }
    else if (!rb_str_to_cstr(str)) {
        rb_raise(rb_eArgError, "nul-separated glob pattern is deprecated");
    }
    else {
        rb_enc_check(str, rb_enc_from_encoding(rb_usascii_encoding()));
    }
    ary = rb_ary_new();

    status = push_glob(ary, str, base, flags);
    if (status) GLOB_JUMP_TAG(status);

    return ary;
}

static VALUE
dir_globs(VALUE args, VALUE base, int flags)
{
    VALUE ary = rb_ary_new();
    long i;

    for (i = 0; i < RARRAY_LEN(args); ++i) {
        int status;
        VALUE str = RARRAY_AREF(args, i);
        FilePathValue(str);
        status = push_glob(ary, str, base, flags);
        if (status) GLOB_JUMP_TAG(status);
    }
    RB_GC_GUARD(args);

    return ary;
}

static VALUE
dir_glob_option_base(VALUE base)
{
    if (NIL_OR_UNDEF_P(base)) {
        return Qnil;
    }
#if USE_OPENDIR_AT
    if (rb_typeddata_is_kind_of(base, &dir_data_type)) {
        return base;
    }
#endif
    FilePathValue(base);
    if (!RSTRING_LEN(base)) return Qnil;
    return base;
}

static int
dir_glob_option_sort(VALUE sort)
{
    return (rb_bool_expected(sort, "sort", TRUE) ? 0 : FNM_GLOB_NOSORT);
}

static VALUE
dir_s_aref(rb_execution_context_t *ec, VALUE obj, VALUE args, VALUE base, VALUE sort)
{
    const int flags = dir_glob_option_sort(sort);
    base = dir_glob_option_base(base);
    if (RARRAY_LEN(args) == 1) {
        return rb_push_glob(RARRAY_AREF(args, 0), base, flags);
    }
    return dir_globs(args, base, flags);
}

static VALUE
dir_s_glob(rb_execution_context_t *ec, VALUE obj, VALUE str, VALUE rflags, VALUE base, VALUE sort)
{
    VALUE ary = rb_check_array_type(str);
    const int flags = (NUM2INT(rflags) | dir_glob_option_sort(sort)) & ~FNM_CASEFOLD;
    base = dir_glob_option_base(base);
    if (NIL_P(ary)) {
        ary = rb_push_glob(str, base, flags);
    }
    else {
        ary = dir_globs(ary, base, flags);
    }

    if (rb_block_given_p()) {
        rb_ary_each(ary);
        return Qnil;
    }
    return ary;
}

static VALUE
dir_open_dir(int argc, VALUE *argv)
{
    VALUE dir = rb_funcallv_kw(rb_cDir, rb_intern("open"), argc, argv, RB_PASS_CALLED_KEYWORDS);

    rb_check_typeddata(dir, &dir_data_type);
    return dir;
}


/*
 * call-seq:
 *   Dir.foreach(dirpath, encoding: 'UTF-8') {|entry_name| ... }  -> nil
 *
 * Calls the block with each entry name in the directory at +dirpath+;
 * sets the given encoding onto each passed +entry_name+:
 *
 *   Dir.foreach('/example') {|entry_name| p entry_name }
 *
 * Output:
 *
 *   "config.h"
 *   "lib"
 *   "main.rb"
 *   ".."
 *   "."
 *
 * Encoding:
 *
 *   Dir.foreach('/example') {|entry_name| p entry_name.encoding; break }
 *   Dir.foreach('/example', encoding: 'US-ASCII') {|entry_name| p entry_name.encoding; break }
 *
 * Output:
 *
 *   #<Encoding:UTF-8>
 *   #<Encoding:US-ASCII>
 *
 * See {String Encoding}[rdoc-ref:encodings.rdoc@String+Encoding].
 *
 * Returns an enumerator if no block is given.
 */
static VALUE
dir_foreach(int argc, VALUE *argv, VALUE io)
{
    VALUE dir;

    RETURN_ENUMERATOR(io, argc, argv);
    dir = dir_open_dir(argc, argv);
    rb_ensure(dir_each, dir, dir_close, dir);
    return Qnil;
}

static VALUE
dir_entry_ary_push(VALUE ary, VALUE entry, struct dir_entry_args *_unused)
{
    return rb_ary_push(ary, entry);
}

static VALUE
dir_collect(VALUE dir)
{
    VALUE ary = rb_ary_new();
    dir_each_entry(dir, dir_entry_ary_push, ary, FALSE);
    return ary;
}

/*
 * call-seq:
 *   Dir.entries(dirname, encoding: 'UTF-8') -> array
 *
 * Returns an array of the entry names in the directory at +dirpath+;
 * sets the given encoding onto each returned entry name:
 *
 *   Dir.entries('/example') # => ["config.h", "lib", "main.rb", "..", "."]
 *   Dir.entries('/example').first.encoding
 *   # => #<Encoding:UTF-8>
 *   Dir.entries('/example', encoding: 'US-ASCII').first.encoding
 *   # => #<Encoding:US-ASCII>
 *
 * See {String Encoding}[rdoc-ref:encodings.rdoc@String+Encoding].
 *
 * Raises an exception if the directory does not exist.
 */
static VALUE
dir_entries(int argc, VALUE *argv, VALUE io)
{
    VALUE dir;

    dir = dir_open_dir(argc, argv);
    return rb_ensure(dir_collect, dir, dir_close, dir);
}

static VALUE
dir_each_child(VALUE dir)
{
    return dir_each_entry(dir, dir_yield, Qnil, TRUE);
}

/*
 * call-seq:
 *   Dir.each_child(dirpath) {|entry_name| ... } -> nil
 *   Dir.each_child(dirpath, encoding: 'UTF-8') {|entry_name| ... }  -> nil
 *
 * Like Dir.foreach, except that entries <tt>'.'</tt> and <tt>'..'</tt>
 * are not included.
 */
static VALUE
dir_s_each_child(int argc, VALUE *argv, VALUE io)
{
    VALUE dir;

    RETURN_ENUMERATOR(io, argc, argv);
    dir = dir_open_dir(argc, argv);
    rb_ensure(dir_each_child, dir, dir_close, dir);
    return Qnil;
}

/*
 * call-seq:
 *   each_child {|entry_name| ... } -> self
 *
 * Calls the block with each entry name in +self+
 * except <tt>'.'</tt> and <tt>'..'</tt>:
 *
 *   dir = Dir.new('/example')
 *   dir.each_child {|entry_name| p entry_name }
 *
 * Output:
 *
 *   "config.h"
 *   "lib"
 *   "main.rb"
 *
 * If no block is given, returns an enumerator.
 */
static VALUE
dir_each_child_m(VALUE dir)
{
    RETURN_ENUMERATOR(dir, 0, 0);
    return dir_each_entry(dir, dir_yield, Qnil, TRUE);
}

/*
 * call-seq:
 *   children -> array
 *
 * Returns an array of the entry names in +self+
 * except for <tt>'.'</tt> and <tt>'..'</tt>:
 *
 *   dir = Dir.new('/example')
 *   dir.children # => ["config.h", "lib", "main.rb"]
 *
 */
static VALUE
dir_collect_children(VALUE dir)
{
    VALUE ary = rb_ary_new();
    dir_each_entry(dir, dir_entry_ary_push, ary, TRUE);
    return ary;
}

/*
 * call-seq:
 *   children -> array
 *
 * Returns an array of the entry names in +self+ along with their type
 * except for <tt>'.'</tt> and <tt>'..'</tt>:
 *
 *   dir = Dir.new('/example')
 *   dir.scan # => [["config.h", :file], ["lib", :directory], ["main.rb", :file]]
 *
 */
static VALUE
dir_scan_children(VALUE dir)
{
    if (rb_block_given_p()) {
        dir_each_entry(dir, dir_yield_with_type, Qnil, TRUE);
        return Qnil;
    }
    else {
        VALUE ary = rb_ary_new();
        dir_each_entry(dir, dir_yield_with_type, ary, TRUE);
        return ary;
    }
}

/*
 * call-seq:
 *   Dir.children(dirpath) -> array
 *   Dir.children(dirpath, encoding: 'UTF-8') -> array
 *
 * Returns an array of the entry names in the directory at +dirpath+
 * except for <tt>'.'</tt> and <tt>'..'</tt>;
 * sets the given encoding onto each returned entry name:
 *
 *   Dir.children('/example') # => ["config.h", "lib", "main.rb"]
 *   Dir.children('/example').first.encoding
 *   # => #<Encoding:UTF-8>
 *   Dir.children('/example', encoding: 'US-ASCII').first.encoding
 *   # => #<Encoding:US-ASCII>
 *
 * See {String Encoding}[rdoc-ref:encodings.rdoc@String+Encoding].
 *
 * Raises an exception if the directory does not exist.
 */
static VALUE
dir_s_children(int argc, VALUE *argv, VALUE io)
{
    VALUE dir;

    dir = dir_open_dir(argc, argv);
    return rb_ensure(dir_collect_children, dir, dir_close, dir);
}

/*
 * call-seq:
 *   Dir.scan(dirpath) {|entry_name, entry_type| ... } -> nil
 *   Dir.scan(dirpath, encoding: 'UTF-8') {|entry_name, entry_type| ... } -> nil
 *   Dir.scan(dirpath) -> [[entry_name, entry_type], ...]
 *   Dir.scan(dirpath, encoding: 'UTF-8') -> [[entry_name, entry_type], ...]
 *
 * Yields or returns an array of the entry names in the directory at +dirpath+
 * associated with their type, except for <tt>'.'</tt> and <tt>'..'</tt>;
 * sets the given encoding onto each returned entry name.
 *
 *  The type symbol is one of:
 *  ``<code>:file</code>'', ``<code>:directory</code>'',
 *  ``<code>:characterSpecial</code>'', ``<code>:blockSpecial</code>'',
 *  ``<code>:fifo</code>'', ``<code>:link</code>'',
 *  or ``<code>:socket</code>'':
 *
 *   Dir.children('/example') # => [["config.h", :file], ["lib", :directory], ["main.rb", :file]]
 *   Dir.children('/example').first.first.encoding
 *   # => #<Encoding:UTF-8>
 *   Dir.children('/example', encoding: 'US-ASCII').first.encoding
 *   # => #<Encoding:US-ASCII>
 *
 * See {String Encoding}[rdoc-ref:encodings.rdoc@String+Encoding].
 *
 * Raises an exception if the directory does not exist.
 */
static VALUE
dir_s_scan(int argc, VALUE *argv, VALUE klass)
{
    VALUE dir = dir_open_dir(argc, argv);
    return rb_ensure(dir_scan_children, dir, dir_close, dir);
}

static int
fnmatch_brace(const char *pattern, VALUE val, void *enc)
{
    struct brace_args *arg = (struct brace_args *)val;
    VALUE path = arg->value;
    rb_encoding *enc_pattern = enc;
    rb_encoding *enc_path = rb_enc_get(path);

    if (enc_pattern != enc_path) {
        if (!rb_enc_asciicompat(enc_pattern))
            return FNM_NOMATCH;
        if (!rb_enc_asciicompat(enc_path))
            return FNM_NOMATCH;
        if (!rb_enc_str_asciionly_p(path)) {
            int cr = ENC_CODERANGE_7BIT;
            long len = strlen(pattern);
            if (rb_str_coderange_scan_restartable(pattern, pattern + len,
                                                  enc_pattern, &cr) != len)
                return FNM_NOMATCH;
            if (cr != ENC_CODERANGE_7BIT)
                return FNM_NOMATCH;
        }
    }
    return (fnmatch(pattern, enc, RSTRING_PTR(path), arg->flags) == 0);
}

/* :nodoc: */
static VALUE
file_s_fnmatch(int argc, VALUE *argv, VALUE obj)
{
    VALUE pattern, path;
    VALUE rflags;
    int flags;

    if (rb_scan_args(argc, argv, "21", &pattern, &path, &rflags) == 3)
        flags = NUM2INT(rflags);
    else
        flags = 0;

    StringValueCStr(pattern);
    FilePathStringValue(path);

    if (flags & FNM_EXTGLOB) {
        struct brace_args args;

        args.value = path;
        args.flags = flags;
        if (ruby_brace_expand(RSTRING_PTR(pattern), flags, fnmatch_brace,
                              (VALUE)&args, rb_enc_get(pattern), pattern) > 0)
            return Qtrue;
    }
    else {
        rb_encoding *enc = rb_enc_compatible(pattern, path);
        if (!enc) return Qfalse;
        if (fnmatch(RSTRING_PTR(pattern), enc, RSTRING_PTR(path), flags) == 0)
            return Qtrue;
    }
    RB_GC_GUARD(pattern);

    return Qfalse;
}

/*
 * call-seq:
 *   Dir.home(user_name = nil) -> dirpath
 *
 * Returns the home directory path of the user specified with +user_name+
 * if it is not +nil+, or the current login user:
 *
 *   Dir.home         # => "/home/me"
 *   Dir.home('root') # => "/root"
 *
 * Raises ArgumentError if +user_name+ is not a user name.
 */
static VALUE
dir_s_home(int argc, VALUE *argv, VALUE obj)
{
    VALUE user;
    const char *u = 0;

    rb_check_arity(argc, 0, 1);
    user = (argc > 0) ? argv[0] : Qnil;
    if (!NIL_P(user)) {
        StringValue(user);
        rb_must_asciicompat(user);
        u = StringValueCStr(user);
        if (*u) {
            return rb_home_dir_of(user, rb_str_new(0, 0));
        }
    }
    return rb_default_home_dir(rb_str_new(0, 0));

}

#if 0
/*
 * call-seq:
 *   Dir.exist?(dirpath) ->  true or false
 *
 * Returns whether +dirpath+ is a directory in the underlying file system:
 *
 *   Dir.exist?('/example')         # => true
 *   Dir.exist?('/nosuch')          # => false
 *   Dir.exist?('/example/main.rb') # => false
 *
 * Same as File.directory?.
 *
 */
VALUE
rb_file_directory_p(void)
{
}
#endif

static void *
nogvl_dir_empty_p(void *ptr)
{
    const char *path = ptr;
    DIR *dir = opendir(path);
    struct dirent *dp;
    VALUE result = Qtrue;

    if (!dir) {
        int e = errno;
        switch (gc_for_fd_with_gvl(e)) {
          default:
            dir = opendir(path);
            if (dir) break;
            e = errno;
            /* fall through */
          case 0:
            if (e == ENOTDIR) return (void *)Qfalse;
            return (void *)INT2FIX(e);
        }
    }
    while ((dp = READDIR_NOGVL(dir, NULL)) != NULL) {
        if (!to_be_skipped(dp)) {
            result = Qfalse;
            break;
        }
    }
    check_closedir(dir);
    return (void *)result;
}

/*
 * call-seq:
 *   Dir.empty?(dirpath) ->  true or false
 *
 * Returns whether +dirpath+ specifies an empty directory:
 *
 *   dirpath = '/tmp/foo'
 *   Dir.mkdir(dirpath)
 *   Dir.empty?(dirpath)            # => true
 *   Dir.empty?('/example')         # => false
 *   Dir.empty?('/example/main.rb') # => false
 *
 * Raises an exception if +dirpath+ does not specify a directory or file
 * in the underlying file system.
 */
static VALUE
rb_dir_s_empty_p(VALUE obj, VALUE dirname)
{
    VALUE result, orig;
    const char *path;
    enum {false_on_notdir = 1};

    FilePathValue(dirname);
    orig = rb_str_dup_frozen(dirname);
    dirname = rb_str_encode_ospath(dirname);
    dirname = rb_str_dup_frozen(dirname);
    path = RSTRING_PTR(dirname);

#if defined HAVE_GETATTRLIST && defined ATTR_DIR_ENTRYCOUNT
    {
        u_int32_t attrbuf[SIZEUP32(fsobj_tag_t)];
        struct attrlist al = {ATTR_BIT_MAP_COUNT, 0, ATTR_CMN_OBJTAG,};
        struct getattrlist_args args = GETATTRLIST_ARGS(&al, attrbuf, 0);
        if (gvl_getattrlist(&args, path) != 0)
            rb_sys_fail_path(orig);
        if (*(const fsobj_tag_t *)(attrbuf+1) == VT_HFS) {
            al.commonattr = 0;
            al.dirattr = ATTR_DIR_ENTRYCOUNT;
            if (gvl_getattrlist(&args, path) == 0) {
                if (attrbuf[0] >= 2 * sizeof(u_int32_t))
                    return RBOOL(attrbuf[1] == 0);
                if (false_on_notdir) return Qfalse;
            }
            rb_sys_fail_path(orig);
        }
    }
#endif

    result = (VALUE)IO_WITHOUT_GVL(nogvl_dir_empty_p, (void *)path);
    if (FIXNUM_P(result)) {
        rb_syserr_fail_path((int)FIX2LONG(result), orig);
    }
    return result;
}

void
Init_Dir(void)
{
    sym_directory = ID2SYM(rb_intern("directory"));
    sym_link = ID2SYM(rb_intern("link"));
    sym_file = ID2SYM(rb_intern("file"));
    sym_unknown = ID2SYM(rb_intern("unknown"));

#if defined(DT_BLK) || defined(S_IFBLK)
    sym_block_device = ID2SYM(rb_intern("blockSpecial"));
#endif
#if defined(DT_CHR) || defined(S_IFCHR)
    sym_character_device = ID2SYM(rb_intern("characterSpecial"));
#endif
#if defined(DT_FIFO) || defined(S_IFIFO)
    sym_fifo = ID2SYM(rb_intern("fifo"));
#endif
#if defined(DT_SOCK) || defined(S_IFSOCK)
    sym_socket = ID2SYM(rb_intern("socket"));
#endif

    rb_gc_register_address(&chdir_lock.path);
    rb_gc_register_address(&chdir_lock.thread);
    rb_gc_register_address(&last_cwd);

    rb_cDir = rb_define_class("Dir", rb_cObject);

    rb_include_module(rb_cDir, rb_mEnumerable);

    rb_define_alloc_func(rb_cDir, dir_s_alloc);
    rb_define_singleton_method(rb_cDir,"for_fd", dir_s_for_fd, 1);
    rb_define_singleton_method(rb_cDir, "foreach", dir_foreach, -1);
    rb_define_singleton_method(rb_cDir, "entries", dir_entries, -1);
    rb_define_singleton_method(rb_cDir, "each_child", dir_s_each_child, -1);
    rb_define_singleton_method(rb_cDir, "children", dir_s_children, -1);
    rb_define_singleton_method(rb_cDir, "scan", dir_s_scan, -1);

    rb_define_method(rb_cDir,"fileno", dir_fileno, 0);
    rb_define_method(rb_cDir,"path", dir_path, 0);
    rb_define_method(rb_cDir,"to_path", dir_path, 0);
    rb_define_method(rb_cDir,"inspect", dir_inspect, 0);
    rb_define_method(rb_cDir,"read", dir_read, 0);
    rb_define_method(rb_cDir,"each", dir_each, 0);
    rb_define_method(rb_cDir,"each_child", dir_each_child_m, 0);
    rb_define_method(rb_cDir,"children", dir_collect_children, 0);
    rb_define_method(rb_cDir,"scan", dir_scan_children, 0);
    rb_define_method(rb_cDir,"rewind", dir_rewind, 0);
    rb_define_method(rb_cDir,"tell", dir_tell, 0);
    rb_define_method(rb_cDir,"seek", dir_seek, 1);
    rb_define_method(rb_cDir,"pos", dir_tell, 0);
    rb_define_method(rb_cDir,"pos=", dir_set_pos, 1);
    rb_define_method(rb_cDir,"close", dir_close, 0);
    rb_define_method(rb_cDir,"chdir", dir_chdir, 0);

    rb_define_singleton_method(rb_cDir,"fchdir", dir_s_fchdir, 1);
    rb_define_singleton_method(rb_cDir,"chdir", dir_s_chdir, -1);
    rb_define_singleton_method(rb_cDir,"getwd", dir_s_getwd, 0);
    rb_define_singleton_method(rb_cDir,"pwd", dir_s_getwd, 0);
    rb_define_singleton_method(rb_cDir,"chroot", dir_s_chroot, 1);
    rb_define_singleton_method(rb_cDir,"mkdir", dir_s_mkdir, -1);
    rb_define_singleton_method(rb_cDir,"rmdir", dir_s_rmdir, 1);
    rb_define_singleton_method(rb_cDir,"delete", dir_s_rmdir, 1);
    rb_define_singleton_method(rb_cDir,"unlink", dir_s_rmdir, 1);
    rb_define_singleton_method(rb_cDir,"home", dir_s_home, -1);

    rb_define_singleton_method(rb_cDir,"exist?", rb_file_directory_p, 1);
    rb_define_singleton_method(rb_cDir,"empty?", rb_dir_s_empty_p, 1);

    rb_define_singleton_method(rb_cFile,"fnmatch", file_s_fnmatch, -1);
    rb_define_singleton_method(rb_cFile,"fnmatch?", file_s_fnmatch, -1);

    /* {File::FNM_NOESCAPE}[rdoc-ref:File::Constants@File-3A-3AFNM_NOESCAPE] */
    rb_file_const("FNM_NOESCAPE", INT2FIX(FNM_NOESCAPE));
    /* {File::FNM_PATHNAME}[rdoc-ref:File::Constants@File-3A-3AFNM_PATHNAME] */
    rb_file_const("FNM_PATHNAME", INT2FIX(FNM_PATHNAME));
    /* {File::FNM_DOTMATCH}[rdoc-ref:File::Constants@File-3A-3AFNM_DOTMATCH] */
    rb_file_const("FNM_DOTMATCH", INT2FIX(FNM_DOTMATCH));
    /* {File::FNM_CASEFOLD}[rdoc-ref:File::Constants@File-3A-3AFNM_CASEFOLD] */
    rb_file_const("FNM_CASEFOLD", INT2FIX(FNM_CASEFOLD));
    /* {File::FNM_EXTGLOB}[rdoc-ref:File::Constants@File-3A-3AFNM_EXTGLOB] */
    rb_file_const("FNM_EXTGLOB", INT2FIX(FNM_EXTGLOB));
    /* {File::FNM_SYSCASE}[rdoc-ref:File::Constants@File-3A-3AFNM_SYSCASE] */
    rb_file_const("FNM_SYSCASE", INT2FIX(FNM_SYSCASE));
    /* {File::FNM_SHORTNAME}[rdoc-ref:File::Constants@File-3A-3AFNM_SHORTNAME] */
    rb_file_const("FNM_SHORTNAME", INT2FIX(FNM_SHORTNAME));
}

#include "dir.rbinc"