File Coverage

libeio/eio.c

Criterion	Covered	Total	%
statement	249	599	41.5
branch	125	358	34.9
condition			n/a
subroutine			n/a
pod			n/a
total	374	957	39.0

/*
  * libeio implementation
  *
  * Copyright (c) 2007,2008,2009,2010,2011,2012,2013,2016,2017,2018,2019 Marc Alexander Lehmann <[e-mail]>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modifica-
  * tion, are permitted provided that the following conditions are met:
  *
  *   1.  Redistributions of source code must retain the above copyright notice,
  *       this list of conditions and the following disclaimer.
  *
  *   2.  Redistributions in binary form must reproduce the above copyright
  *       notice, this list of conditions and the following disclaimer in the
  *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
  * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
  * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
  * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Alternatively, the contents of this file may be used under the terms of
  * the GNU General Public License ("GPL") version 2 or any later version,
  * in which case the provisions of the GPL are applicable instead of
  * the above. If you wish to allow the use of your version of this file
  * only under the terms of the GPL and not to allow others to use your
  * version of this file under the BSD license, indicate your decision
  * by deleting the provisions above and replace them with the notice
  * and other provisions required by the GPL. If you do not delete the
  * provisions above, a recipient may use your version of this file under
  * either the BSD or the GPL.
  */

#ifndef _WIN32
# include "config.h"
#endif

#include "eio.h"
#include "ecb.h"

#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <limits.h>
#include <fcntl.h>
#include <assert.h>

/* intptr_t comes from unistd.h, says POSIX/UNIX/tradition */
/* intptr_t only comes from stdint.h, says idiot openbsd coder */
#if HAVE_STDINT_H
# include <stdint.h>
#endif

#ifndef ECANCELED
# define ECANCELED EDOM
#endif
#ifndef ELOOP
# define ELOOP EDOM
#endif

#if !defined(ENOTSOCK) && defined(WSAENOTSOCK)
# define ENOTSOCK WSAENOTSOCK
#endif

static void eio_destroy (eio_req *req);

#ifndef EIO_FINISH
# define EIO_FINISH(req)  ((req)->finish) && !EIO_CANCELLED (req) ? (req)->finish (req) : 0
#endif

#ifndef EIO_DESTROY
# define EIO_DESTROY(req) do { if ((req)->destroy) (req)->destroy (req); } while (0)
#endif

#ifndef EIO_FEED
# define EIO_FEED(req)    do { if ((req)->feed   ) (req)->feed    (req); } while (0)
#endif

#ifndef EIO_FD_TO_WIN32_HANDLE
# define EIO_FD_TO_WIN32_HANDLE(fd) _get_osfhandle (fd)
#endif
#ifndef EIO_WIN32_HANDLE_TO_FD
# define EIO_WIN32_HANDLE_TO_FD(handle) _open_osfhandle (handle, 0)
#endif

#define EIO_ERRNO(errval,retval) ((errno = errval), retval)

#define EIO_ENOSYS() EIO_ERRNO (ENOSYS, -1)

#ifdef _WIN32

    #undef PAGESIZE
    #define PAGESIZE 4096 /* GetSystemInfo? */

    /* TODO: look at how perl does stat (non-sloppy), unlink (ro-files), utime, link */

    #ifdef EIO_STRUCT_STATI64
        /* look at perl's non-sloppy stat */
        #define stat(path,buf)       _stati64 (path,buf)
    #define fstat(fd,buf)        _fstati64 (fd,buf)
  #endif
  #define lstat(path,buf)      stat (path,buf)
  #define fsync(fd)            (FlushFileBuffers ((HANDLE)EIO_FD_TO_WIN32_HANDLE (fd)) ? 0 : EIO_ERRNO (EBADF, -1))
  #define mkdir(path,mode)     _mkdir (path)
  #define link(old,neu)        (CreateHardLink (neu, old, 0) ? 0 : EIO_ERRNO (ENOENT, -1))

  #define chmod(path,mode)     _chmod (path, mode)
  #define dup(fd)              _dup (fd)
  #define dup2(fd1,fd2)        _dup2 (fd1, fd2)
  #define pipe(fds)            _pipe (fds, 4096, O_BINARY)

  #define fcntl(fd,cmd,arg)    EIO_ENOSYS ()
  #define ioctl(fd,cmd,arg)    EIO_ENOSYS ()
  #define fchmod(fd,mode)      EIO_ENOSYS ()
  #define chown(path,uid,gid)  EIO_ENOSYS ()
  #define fchown(fd,uid,gid)   EIO_ENOSYS ()
  #define truncate(path,offs)  EIO_ENOSYS () /* far-miss: SetEndOfFile */
  #define ftruncate(fd,offs)   EIO_ENOSYS () /* near-miss: SetEndOfFile */
  #define mknod(path,mode,dev) EIO_ENOSYS ()
  #define sync()               EIO_ENOSYS ()
  #define readlink(path,buf,s) EIO_ENOSYS ()
  #define statvfs(path,buf)    EIO_ENOSYS ()
  #define fstatvfs(fd,buf)     EIO_ENOSYS ()

  #define pread(fd,buf,count,offset)  eio__pread  (fd, buf, count, offset)
  #define pwrite(fd,buf,count,offset) eio__pwrite (fd, buf, count, offset)

  #if __GNUC__
    typedef long long eio_off_t; /* signed for compatibility to msvc */
  #else
    typedef __int64   eio_off_t; /* unsigned not supported by msvc */
  #endif

  static eio_ssize_t
  eio__pread (int fd, void *buf, eio_ssize_t count, eio_off_t offset)
  {
    OVERLAPPED o = { 0 };
    DWORD got;

    o.Offset     = offset;
    o.OffsetHigh = offset >> 32;

    return ReadFile ((HANDLE)EIO_FD_TO_WIN32_HANDLE (fd), buf, count, &got, &o)
         ? got : -1;
  }

  static eio_ssize_t
  eio__pwrite (int fd, void *buf, eio_ssize_t count, eio_off_t offset)
  {
    OVERLAPPED o = { 0 };
    DWORD got;

    o.Offset     = offset;
    o.OffsetHigh = offset >> 32;

    return WriteFile ((HANDLE)EIO_FD_TO_WIN32_HANDLE (fd), buf, count, &got, &o)
         ? got : -1;
  }

  /* rename() uses MoveFile, which fails to overwrite */
  #define rename(old,neu)      eio__rename (old, neu)

  static int
  eio__rename (const char *old, const char *neu)
  {
    if (MoveFileEx (old, neu, MOVEFILE_REPLACE_EXISTING))
      return 0;

    /* should steal _dosmaperr */
    switch (GetLastError ())
      {
        case ERROR_FILE_NOT_FOUND:
        case ERROR_PATH_NOT_FOUND:
        case ERROR_INVALID_DRIVE:
        case ERROR_NO_MORE_FILES:
        case ERROR_BAD_NETPATH:
        case ERROR_BAD_NET_NAME:
        case ERROR_BAD_PATHNAME:
        case ERROR_FILENAME_EXCED_RANGE:
          errno = ENOENT;
          break;

        default:
          errno = EACCES;
          break;
      }

    return -1;
  }

  /* we could even stat and see if it exists */
  static int
  symlink (const char *old, const char *neu)
  {
    #if WINVER >= 0x0600
      int flags;

      /* This tries out all combinations of SYMBOLIC_LINK_FLAG_DIRECTORY
              * and SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE,
              * with directory first.
              */
      for (flags = 3; flags >= 0; --flags)
        if (CreateSymbolicLink (neu, old, flags))
          return 0;
    #endif

    return EIO_ERRNO (ENOENT, -1);
  }

  /* POSIX API only, causing trouble for win32 apps */
  #define CreateHardLink(neu,old,flags) 0 /* not really creating hardlink, still using relative paths? */
  #define CreateSymbolicLink(neu,old,flags) 0 /* vista+ only */

  struct statvfs
  {
    int dummy;
  };

  #define DT_DIR EIO_DT_DIR
  #define DT_REG EIO_DT_REG
  #define D_NAME(entp) entp.cFileName
  #define D_TYPE(entp) (entp.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY ? DT_DIR : DT_REG)

#else

  #include <sys/ioctl.h>
  #include <sys/time.h>
  #include <sys/select.h>
  #include <unistd.h>
  #include <signal.h>
  #include <dirent.h>

  #ifdef ANDROID
    #include <sys/vfs.h>
    #define statvfs statfs
    #define fstatvfs fstatfs
    #include <asm/page.h> /* supposedly limits.h does #define PAGESIZE PAGESIZE */
  #else
    #include <sys/statvfs.h>
  #endif

  #if _POSIX_MEMLOCK || _POSIX_MEMLOCK_RANGE || _POSIX_MAPPED_FILES
    #include <sys/mman.h>
  #endif

  #define D_NAME(entp) entp->d_name

  /* POSIX_SOURCE is useless on bsd's, and XOPEN_SOURCE is unreliable there, too */
  #if __FreeBSD__ || __NetBSD__ || __OpenBSD__
    #define _DIRENT_HAVE_D_TYPE /* sigh */
    #define D_INO(de) (de)->d_fileno
    #define D_NAMLEN(de) (de)->d_namlen
  #elif __linux || defined d_ino || _XOPEN_SOURCE >= 600
    #define D_INO(de) (de)->d_ino
  #endif

  #ifdef _D_EXACT_NAMLEN
    #undef D_NAMLEN
    #define D_NAMLEN(de) _D_EXACT_NAMLEN (de)
  #endif

  #ifdef _DIRENT_HAVE_D_TYPE
    #define D_TYPE(de) (de)->d_type
  #endif

  #ifndef EIO_STRUCT_DIRENT
    #define EIO_STRUCT_DIRENT struct dirent
  #endif

#endif

#if HAVE_UTIMES
# include <utime.h>
#endif

#if HAVE_SYS_SYSCALL_H
# include <sys/syscall.h>
#endif

#if HAVE_SENDFILE
# if __linux
#  include <sys/sendfile.h>
# elif __FreeBSD__ || defined __APPLE__
#  include <sys/socket.h>
#  include <sys/uio.h>
# elif __hpux
#  include <sys/socket.h>
# elif __solaris
#  include <sys/sendfile.h>
# else
#  error sendfile support requested but not available
# endif
#endif

#if HAVE_RENAMEAT2
# include <sys/syscall.h>
# include <linux/fs.h>
#endif

#ifndef D_TYPE
# define D_TYPE(de) 0
#endif
#ifndef D_INO
# define D_INO(de) 0
#endif
#ifndef D_NAMLEN
# define D_NAMLEN(entp) strlen (D_NAME (entp))
#endif

/* used for struct dirent, AIX doesn't provide it */
#ifndef NAME_MAX
# define NAME_MAX 4096
#endif

/* used for readlink etc. */
#ifndef PATH_MAX
# define PATH_MAX 0
#endif

#ifndef O_CLOEXEC
  #define O_CLOEXEC 0
#endif

#ifndef O_NONBLOCK
  #define O_NONBLOCK 0
#endif

#ifndef O_SEARCH
  #define O_SEARCH O_RDONLY
#endif

#ifndef O_DIRECTORY
  #define O_DIRECTORY 0
#endif

#ifndef EIO_PATH_MIN
# define EIO_PATH_MIN 8160
#endif

#if defined(O_PATH)
# define EIO_O_PATH O_PATH
#elif defined(O_SEARCH)
# define EIO_O_PATH O_SEARCH
#else
# define EIO_O_PATH 0
#endif

#define EIO_PATH_MAX (PATH_MAX <= EIO_PATH_MIN ? EIO_PATH_MIN : PATH_MAX)

/* buffer size for various temporary buffers */
#define EIO_BUFSIZE 65536

#define dBUF					\
    char *eio_buf = malloc (EIO_BUFSIZE);		\
    errno = ENOMEM;				\
    if (!eio_buf)					\
        return -1

#define FUBd					\
    free (eio_buf)

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

struct etp_tmpbuf;

#if _POSIX_VERSION >= 200809L
    #define HAVE_AT 1
    #define WD2FD(wd) ((wd) ? (wd)->fd : AT_FDCWD)
#else
    #define HAVE_AT 0
    static const char *wd_expand (struct etp_tmpbuf *tmpbuf, eio_wd wd, const char *path);
#endif

struct eio_pwd
{
#if HAVE_AT
    int fd;
#endif
    int len;
    char str[1]; /* actually, a 0-terminated canonical path */
};

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

#define ETP_PRI_MIN EIO_PRI_MIN
#define ETP_PRI_MAX EIO_PRI_MAX

#define ETP_TYPE_QUIT -1
#define ETP_TYPE_GROUP EIO_GROUP

static void eio_nop_callback (void) { }
static void (*eio_want_poll_cb)(void) = eio_nop_callback;
static void (*eio_done_poll_cb)(void) = eio_nop_callback;

#define ETP_WANT_POLL(pool) eio_want_poll_cb ()
#define ETP_DONE_POLL(pool) eio_done_poll_cb ()

struct etp_worker;
#define ETP_REQ eio_req
#define ETP_DESTROY(req) eio_destroy (req)
static int eio_finish (eio_req *req);
#define ETP_FINISH(req)  eio_finish (req)
static void eio_execute (struct etp_worker *self, eio_req *req);
#define ETP_EXECUTE(wrk,req) eio_execute (wrk, req)

#include "etp.c"

static struct etp_pool eio_pool;
#define EIO_POOL (&eio_pool)

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

static void
grp_try_feed (eio_req *grp)
{
    while (grp->size < grp->int2 && !EIO_CANCELLED (grp))
        {
            grp->flags &= ~ETP_FLAG_GROUPADD;

            EIO_FEED (grp);

            /* stop if no progress has been made */
            if (!(grp->flags & ETP_FLAG_GROUPADD))
                {
                    grp->feed = 0;
                    break;
                }
        }
}

static int
grp_dec (eio_req *grp)
{
    --grp->size;

    /* call feeder, if applicable */
    grp_try_feed (grp);

    /* finish, if done */
    if (!grp->size && grp->flags & ETP_FLAG_DELAYED)
        return eio_finish (grp);
    else
        return 0;
}

static void
eio_destroy (eio_req *req)
{
    if ((req)->flags & EIO_FLAG_PTR1_FREE) free (req->ptr1);
    if ((req)->flags & EIO_FLAG_PTR2_FREE) free (req->ptr2);

    EIO_DESTROY (req);
}

static int
eio_finish (eio_req *req)
{
    int res = EIO_FINISH (req);

    if (req->grp)
        {
            int res2;
            eio_req *grp = req->grp;

            /* unlink request */
            if (req->grp_next) req->grp_next->grp_prev = req->grp_prev;
            if (req->grp_prev) req->grp_prev->grp_next = req->grp_next;

            if (grp->grp_first == req)
                grp->grp_first = req->grp_next;

            res2 = grp_dec (grp);

            if (!res)
                res = res2;
        }

    eio_destroy (req);

    return res;
}

void
eio_grp_cancel (eio_req *grp)
{
    etp_grp_cancel (EIO_POOL, grp);
}

void
eio_cancel (eio_req *req)
{
    etp_cancel (EIO_POOL, req);
}

void
eio_submit (eio_req *req)
{
    etp_submit (EIO_POOL, req);
}

unsigned int
eio_nreqs (void)
{
    return etp_nreqs (EIO_POOL);
}

unsigned int
eio_nready (void)
{
    return etp_nready (EIO_POOL);
}

unsigned int
eio_npending (void)
{
    return etp_npending (EIO_POOL);
}

unsigned int ecb_cold
eio_nthreads (void)
{
    return etp_nthreads (EIO_POOL);
}

void ecb_cold
eio_set_max_poll_time (double nseconds)
{
    etp_set_max_poll_time (EIO_POOL, nseconds);
}

void ecb_cold
eio_set_max_poll_reqs (unsigned int maxreqs)
{
    etp_set_max_poll_reqs (EIO_POOL, maxreqs);
}

void ecb_cold
eio_set_max_idle (unsigned int nthreads)
{
    etp_set_max_idle (EIO_POOL, nthreads);
}

void ecb_cold
eio_set_idle_timeout (unsigned int seconds)
{
    etp_set_idle_timeout (EIO_POOL, seconds);
}

void ecb_cold
eio_set_min_parallel (unsigned int nthreads)
{
    etp_set_min_parallel (EIO_POOL, nthreads);
}

void ecb_cold
eio_set_max_parallel (unsigned int nthreads)
{
    etp_set_max_parallel (EIO_POOL, nthreads);
}

int eio_poll (void)
{
    return etp_poll (EIO_POOL);
}

/*****************************************************************************/
/* work around various missing functions */

#if HAVE_POSIX_CLOSE && !__linux
# define eio__close(fd) posix_close (fd, 0)
#else
# define eio__close(fd) close (fd)
#endif

/* close() without disturbing errno */
static void
silent_close (int fd)
{
    int saved_errno = errno;
    eio__close (fd);
    errno = saved_errno;
}

#ifndef HAVE_UTIMES

# undef utimes
# define utimes(path,times)  eio__utimes (path, times)

static int
eio__utimes (const char *filename, const struct timeval times[2])
{
    if (times)
        {
            struct utimbuf buf;

            buf.actime  = times[0].tv_sec;
            buf.modtime = times[1].tv_sec;

            return utime (filename, &buf);
        }
    else
        return utime (filename, 0);
}

#endif

#ifndef HAVE_FUTIMES

# undef futimes
# define futimes(fd,times) eio__futimes (fd, times)

static int
eio__futimes (int fd, const struct timeval tv[2])
{
    errno = ENOSYS;
    return -1;
}

#endif

#if !HAVE_FDATASYNC
# undef fdatasync
# define fdatasync(fd) fsync (fd)
#endif

static int
eio__syncfs (int fd)
{
    int res;

#if HAVE_SYS_SYNCFS
    res = (int)syscall (__NR_syncfs, (int)(fd));
#else
    res = EIO_ENOSYS ();
#endif

    if (res < 0 && errno == ENOSYS && fd >= 0)
        sync ();

    return res;
}

/* sync_file_range always needs emulation */
static int
eio__sync_file_range (int fd, off_t offset, size_t nbytes, unsigned int flags)
{
#if HAVE_SYNC_FILE_RANGE
    int res;

    if (EIO_SYNC_FILE_RANGE_WAIT_BEFORE   != SYNC_FILE_RANGE_WAIT_BEFORE
            || EIO_SYNC_FILE_RANGE_WRITE      != SYNC_FILE_RANGE_WRITE
            || EIO_SYNC_FILE_RANGE_WAIT_AFTER != SYNC_FILE_RANGE_WAIT_AFTER)
        {
            flags = 0
                  | (flags & EIO_SYNC_FILE_RANGE_WAIT_BEFORE ? SYNC_FILE_RANGE_WAIT_BEFORE : 0)
                  | (flags & EIO_SYNC_FILE_RANGE_WRITE       ? SYNC_FILE_RANGE_WRITE       : 0)
                  | (flags & EIO_SYNC_FILE_RANGE_WAIT_AFTER  ? SYNC_FILE_RANGE_WAIT_AFTER  : 0);
        }

    res = sync_file_range (fd, offset, nbytes, flags);

    if (!res || errno != ENOSYS)
        return res;
#endif

    /* even though we could play tricks with the flags, it's better to always
   * call fdatasync, as that matches the expectation of its users best */
    return fdatasync (fd);
}

static int
eio__fallocate (int fd, int mode, off_t offset, size_t len)
{
#if HAVE_LINUX_FALLOCATE
    return fallocate (fd, mode, offset, len);
#else
    return EIO_ENOSYS ();
#endif
}

#if !HAVE_READAHEAD
# undef readahead
# define readahead(fd,offset,count) eio__readahead (fd, offset, count, self)

static eio_ssize_t
eio__readahead (int fd, off_t offset, size_t count, etp_worker *self)
{
    size_t todo = count;
    dBUF;

    while (todo > 0)
        {
            size_t len = todo < EIO_BUFSIZE ? todo : EIO_BUFSIZE;

            pread (fd, eio_buf, len, offset);
            offset += len;
            todo   -= len;
        }

    FUBd;

    /* linux's readahead basically only fails for EBADF or EINVAL (not mmappable) */
    /* but not for e.g. EIO or eof, so we also never fail */
    return 0;
}

#endif

/* sendfile always needs emulation */
static eio_ssize_t
eio__sendfile (int ofd, int ifd, off_t offset, size_t count)
{
    eio_ssize_t written = 0;
    eio_ssize_t res;

    if (!count)
        return 0;

    for (;;)
        {
#ifdef __APPLE__
# undef HAVE_SENDFILE /* broken, as everything on os x */
#endif
#if HAVE_SENDFILE
# if __linux
            off_t soffset = offset;
            res = sendfile (ofd, ifd, &soffset, count);

# elif __FreeBSD__
            /*
       * Of course, the freebsd sendfile is a dire hack with no thoughts
       * wasted on making it similar to other I/O functions.
       */
      off_t sbytes;
      res = sendfile (ifd, ofd, offset, count, 0, &sbytes, 0);

      #if 0 /* according to the manpage, this is correct, but broken behaviour */
      /* freebsd' sendfile will return 0 on success */
      /* freebsd 8 documents it as only setting *sbytes on EINTR and EAGAIN, but */
            /* not on e.g. EIO or EPIPE - sounds broken */
            if ((res < 0 && (errno == EAGAIN || errno == EINTR) && sbytes) || res == 0)
                res = sbytes;
            #endif

            /* according to source inspection, this is correct, and useful behaviour */
            if (sbytes)
                res = sbytes;

# elif defined __APPLE__
            off_t sbytes = count;
            res = sendfile (ifd, ofd, offset, &sbytes, 0, 0);

            /* according to the manpage, sbytes is always valid */
            if (sbytes)
                res = sbytes;

# elif __hpux
            res = sendfile (ofd, ifd, offset, count, 0, 0);

# elif __solaris
            struct sendfilevec vec;
            size_t sbytes;

            vec.sfv_fd   = ifd;
            vec.sfv_flag = 0;
            vec.sfv_off  = offset;
            vec.sfv_len  = count;

            res = sendfilev (ofd, &vec, 1, &sbytes);

            if (res < 0 && sbytes)
                res = sbytes;

# endif

#elif defined (_WIN32) && 0
            /* does not work, just for documentation of what would need to be done */
            /* actually, cannot be done like this, as TransmitFile changes the file offset, */
      /* libeio guarantees that the file offset does not change, and windows */
            /* has no way to get an independent handle to the same file description */
            HANDLE h = TO_SOCKET (ifd);
            SetFilePointer (h, offset, 0, FILE_BEGIN);
            res = TransmitFile (TO_SOCKET (ofd), h, count, 0, 0, 0, 0);

#else
            res = EIO_ENOSYS ();
#endif

            /* we assume sendfile can copy at least 128mb in one go */
            if (res <= 128 * 1024 * 1024)
                {
                    if (res > 0)
                        written += res;

                    if (written)
                        return written;

                    break;
                }
            else
                {
                    /* if we requested more, then probably the kernel was lazy */
                    written += res;
                    offset  += res;
                    count   -= res;

                    if (!count)
                        return written;
                }
        }

    if (res < 0
            && (errno == ENOSYS || errno == EINVAL || errno == ENOTSOCK
                    /* BSDs */
#ifdef ENOTSUP /* sigh, if the steenking pile called openbsd would only try to at least compile posix code... */
          || errno == ENOTSUP
#endif
#ifdef EOPNOTSUPP /* windows */
          || errno == EOPNOTSUPP /* BSDs */
#endif
#if __solaris
          || errno == EAFNOSUPPORT || errno == EPROTOTYPE
#endif
         )
      )
    {
      /* emulate sendfile. this is a major pain in the ass */
      dBUF;

      res = 0;

      while (count)
        {
          eio_ssize_t cnt;

          cnt = pread (ifd, eio_buf, count > EIO_BUFSIZE ? EIO_BUFSIZE : count, offset);

          if (cnt <= 0)
            {
              if (cnt && !res) res = -1;
              break;
            }

          cnt = write (ofd, eio_buf, cnt);

          if (cnt <= 0)
            {
              if (cnt && !res) res = -1;
              break;
            }

          offset += cnt;
          res    += cnt;
          count  -= cnt;
        }

      FUBd;
    }

  return res;
}

#ifdef PAGESIZE
# define eio_pagesize() PAGESIZE
#else
static intptr_t
eio_pagesize (void)
{
  static intptr_t page;

  if (!page)
    page = sysconf (_SC_PAGESIZE);

  return page;
}
#endif

static void
eio_page_align (void **addr, size_t *length)
{
  intptr_t mask = eio_pagesize () - 1;

  /* round down addr */
  intptr_t adj = mask & (intptr_t)*addr;

  *addr   = (void *)((intptr_t)*addr - adj);
  *length += adj;

  /* round up length */
  *length = (*length + mask) & ~mask;
}

#if !_POSIX_MEMLOCK
# define eio__mlockall(a) EIO_ENOSYS ()
#else

static int
eio__mlockall (int flags)
{
  #if __GLIBC__ == 2 && __GLIBC_MINOR__ <= 7
    extern int mallopt (int, int);
    mallopt (-6, 238); /* http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=473812 */
    #endif

    #ifndef MCL_ONFAULT
        if (flags & EIO_MCL_ONFAULT)
            return EIO_ERRNO (EINVAL, -1);
        #define MCL_ONFAULT 4
    #endif

    if (EIO_MCL_CURRENT     != MCL_CURRENT
            || EIO_MCL_FUTURE   != MCL_FUTURE
            || EIO_MCL_ONFAULT  != MCL_ONFAULT)
        {
            flags = 0
                  | (flags & EIO_MCL_CURRENT ? MCL_CURRENT : 0)
                  | (flags & EIO_MCL_FUTURE  ? MCL_FUTURE  : 0)
                  | (flags & EIO_MCL_ONFAULT ? MCL_ONFAULT : 0)
            ;
        }

    return mlockall (flags);
}
#endif

#if !_POSIX_MEMLOCK_RANGE
# define eio__mlock(a,b) EIO_ENOSYS ()
#else

static int
eio__mlock (void *addr, size_t length)
{
    eio_page_align (&addr, &length);

    return mlock (addr, length);
}

#endif

#if !(_POSIX_MAPPED_FILES && _POSIX_SYNCHRONIZED_IO)
# define eio__msync(a,b,c) EIO_ENOSYS ()
#else

static int
eio__msync (void *mem, size_t len, int flags)
{
    eio_page_align (&mem, &len);

    if (EIO_MS_ASYNC         != MS_SYNC
            || EIO_MS_INVALIDATE != MS_INVALIDATE
            || EIO_MS_SYNC       != MS_SYNC)
        {
            flags = 0
                  | (flags & EIO_MS_ASYNC      ? MS_ASYNC : 0)
                  | (flags & EIO_MS_INVALIDATE ? MS_INVALIDATE : 0)
                  | (flags & EIO_MS_SYNC       ? MS_SYNC : 0);
        }

    return msync (mem, len, flags);
}

#endif

static int
eio__mtouch (eio_req *req)
{
    void *mem  = req->ptr2;
    size_t len = req->size;
    int flags  = req->int1;

    eio_page_align (&mem, &len);

    {
        intptr_t addr = (intptr_t)mem;
        intptr_t end = addr + len;
        intptr_t page = eio_pagesize ();

        if (addr < end)
            if (flags & EIO_MT_MODIFY) /* modify */
                do { *((volatile sig_atomic_t *)addr) |= 0; } while ((addr += page) < end && !EIO_CANCELLED (req));
            else
                do { *((volatile sig_atomic_t *)addr)     ; } while ((addr += page) < end && !EIO_CANCELLED (req));
    }

    return 0;
}

/*****************************************************************************/
/* requests implemented outside eio_execute, because they are so large */

static void
eio__lseek (eio_req *req)
{
    /* this usually gets optimised away completely, or your compiler sucks, */
  /* or the whence constants really are not 0, 1, 2 */
    int whence = req->int2 == EIO_SEEK_SET ? SEEK_SET
                          : req->int2 == EIO_SEEK_CUR ? SEEK_CUR
                          : req->int2 == EIO_SEEK_END ? SEEK_END
                          : req->int2;

    req->offs   = lseek (req->int1, req->offs, whence);
    req->result = req->offs == (off_t)-1 ? -1 : 0;
}

/* result will always end up in tmpbuf, there is always space for adding a 0-byte */
static int
eio__realpath (struct etp_tmpbuf *tmpbuf, eio_wd wd, const char *path)
{
    char *res;
    const char *rel = path;
    char *tmp1, *tmp2;
#if SYMLOOP_MAX > 32
    int symlinks = SYMLOOP_MAX;
#else
    int symlinks = 32;
#endif

    errno = EINVAL;
    if (!rel)
        return -1;

    errno = ENOENT;
    if (!*rel)
        return -1;

    res = etp_tmpbuf_get (tmpbuf, EIO_PATH_MAX * 3);
#ifdef _WIN32
    if (_access (rel, 4) != 0)
        return -1;

    symlinks = GetFullPathName (rel, EIO_PATH_MAX * 3, res, 0);

    errno = ENAMETOOLONG;
    if (symlinks >= EIO_PATH_MAX * 3)
        return -1;

    errno = EIO;
    if (symlinks <= 0)
        return -1;

    return symlinks;

#else
    tmp1 = res  + EIO_PATH_MAX;
    tmp2 = tmp1 + EIO_PATH_MAX;

#if 0 /* disabled, the musl way to do things is just too racy */
#if __linux && defined(O_NONBLOCK) && defined(O_NOATIME)
    /* on linux we may be able to ask the kernel */
    {
        int fd = open (rel, O_RDONLY | O_NONBLOCK | O_NOCTTY | O_NOATIME);

        if (fd >= 0)
            {
                sprintf (tmp1, "/proc/self/fd/%d", fd);
                req->result = readlink (tmp1, res, EIO_PATH_MAX);
                /* here we should probably stat the open file and the disk file, to make sure they still match */
                eio__close (fd);

                if (req->result > 0)
                    goto done;
            }
        else if (errno == ELOOP || errno == ENAMETOOLONG || errno == ENOENT || errno == ENOTDIR || errno == EIO)
            return -1;
    }
#endif
#endif

    if (*rel != '/')
        {
            int len;

            errno = ENOENT;
            if (wd == EIO_INVALID_WD)
                return -1;

            if (wd == EIO_CWD)
                {
                    if (!getcwd (res, EIO_PATH_MAX))
                        return -1;

                    len = strlen (res);
                }
            else
                memcpy (res, wd->str, len = wd->len);

            if (res [1]) /* only use if not / */
                res += len;
        }

    while (*rel)
        {
            eio_ssize_t len, linklen;
            const char *beg = rel;

            while (*rel && *rel != '/')
                ++rel;

            len = rel - beg;

            if (!len) /* skip slashes */
                {
                    ++rel;
                    continue;
                }

            if (beg [0] == '.')
                {
                    if (len == 1)
                        continue; /* . - nop */

                    if (beg [1] == '.' && len == 2)
                        {
                            /* .. - back up one component, if possible */

                            while (res != tmpbuf->ptr)
                                if (*--res == '/')
                                    break;

                            continue;
                        }
                }

                errno = ENAMETOOLONG;
                if (res + 1 + len + 1 >= tmp1)
                    return -1;

                /* copy one component */
                *res = '/';
                memcpy (res + 1, beg, len);

                /* zero-terminate, for readlink */
                res [len + 1] = 0;

                /* now check if it's a symlink */
                linklen = readlink (tmpbuf->ptr, tmp1, EIO_PATH_MAX);

                if (linklen < 0)
                    {
                        if (errno != EINVAL)
                            return -1;

                        /* it's a normal directory. hopefully */
                        res += len + 1;
                    }
                else
                    {
                        /* yay, it was a symlink - build new path in tmp2 */
                        int rellen = strlen (rel);

                        errno = ENAMETOOLONG;
                        if (linklen + 1 + rellen >= EIO_PATH_MAX) /* also catch linklen >= EIO_PATH_MAX */
                            return -1;

                        errno = ELOOP;
                        if (!--symlinks)
                            return -1;

                        if (*tmp1 == '/')
                            res = tmpbuf->ptr; /* symlink resolves to an absolute path */

                        /* we need to be careful, as rel might point into tmp2 already */
                        memmove (tmp2 + linklen + 1, rel, rellen + 1);
                        tmp2 [linklen] = '/';
                        memcpy (tmp2, tmp1, linklen);

                        rel = tmp2;
                    }
        }

    /* special case for the lone root path */
    if (res == tmpbuf->ptr)
        *res++ = '/';

    return res - (char *)tmpbuf->ptr;
#endif
}

static signed char
eio_dent_cmp (const eio_dirent *a, const eio_dirent *b)
{
    return a->score - b->score ? a->score - b->score /* works because our signed char is always 0..100 */
              : a->inode < b->inode ? -1
              : a->inode > b->inode ?  1
              :                        0;
}

#define EIO_DENT_CMP(i,op,j) eio_dent_cmp (&i, &j) op 0

#define EIO_SORT_CUTOFF 30 /* quite high, but performs well on many filesystems */
#define EIO_SORT_FAST   60 /* when to only use insertion sort */

static void
eio_dent_radix_sort (eio_dirent *dents, int size, signed char score_bits, eio_ino_t inode_bits)
{
    unsigned char bits [9 + sizeof (eio_ino_t) * 8];
    unsigned char *bit = bits;

    assert (CHAR_BIT == 8);
    assert (sizeof (eio_dirent) * 8 < 256);
    assert (offsetof (eio_dirent, inode)); /* we use bit #0 as sentinel */
    assert (offsetof (eio_dirent, score)); /* we use bit #0 as sentinel */

    if (size <= EIO_SORT_FAST)
        return;

    /* first prepare an array of bits to test in our radix sort */
    /* try to take endianness into account, as well as differences in eio_ino_t sizes */
    /* inode_bits must contain all inodes ORed together */
    /* which is used to skip bits that are 0 everywhere, which is very common */
    {
        eio_ino_t endianness;
        int i, j;

        /* we store the byte offset of byte n into byte n of "endianness" */
        for (i = 0; i < sizeof (eio_ino_t); ++i)
            ((unsigned char *)&endianness)[i] = i;

        *bit++ = 0;

        for (i = 0; i < sizeof (eio_ino_t); ++i)
            {
                /* shifting off the byte offsets out of "endianness" */
                int offs = (offsetof (eio_dirent, inode) + (endianness & 0xff)) * 8;
                endianness >>= 8;

                for (j = 0; j < 8; ++j)
                    if (inode_bits & (((eio_ino_t)1) << (i * 8 + j)))
                        *bit++ = offs + j;
            }

        for (j = 0; j < 8; ++j)
            if (score_bits & (1 << j))
                *bit++ = offsetof (eio_dirent, score) * 8 + j;
    }

    /* now actually do the sorting (a variant of MSD radix sort) */
    {
        eio_dirent    *base_stk [9 + sizeof (eio_ino_t) * 8], *base;
        eio_dirent    *end_stk  [9 + sizeof (eio_ino_t) * 8], *end;
        unsigned char *bit_stk  [9 + sizeof (eio_ino_t) * 8];
        int stk_idx = 0;

        base_stk [stk_idx] = dents;
        end_stk  [stk_idx] = dents + size;
        bit_stk  [stk_idx] = bit - 1;

        do
            {
                base = base_stk [stk_idx];
                end  = end_stk  [stk_idx];
                bit  = bit_stk  [stk_idx];

                for (;;)
                    {
                        unsigned char O = *bit >> 3;
                        unsigned char M = 1 << (*bit & 7);

                        eio_dirent *a = base;
                        eio_dirent *b = end;

                        if (b - a < EIO_SORT_CUTOFF)
                            break;

                        /* now bit-partition the array on the bit */
                        /* this ugly asymmetric loop seems to perform much better than typical */
                        /* partition algos found in the literature */
                        do
                            if (!(((unsigned char *)a)[O] & M))
                                ++a;
                            else if (!(((unsigned char *)--b)[O] & M))
                                {
                                    eio_dirent tmp = *a; *a = *b; *b = tmp;
                                    ++a;
                                }
                        while (b > a);

                        /* next bit, or stop, if no bits left in this path */
                        if (!*--bit)
                            break;

                        base_stk [stk_idx] = a;
                        end_stk  [stk_idx] = end;
                        bit_stk  [stk_idx] = bit;
                        ++stk_idx;

                        end = a;
                    }
            }
        while (stk_idx--);
    }
}

static void
eio_dent_insertion_sort (eio_dirent *dents, int size)
{
    /* first move the smallest element to the front, to act as a sentinel */
    {
        int i;
        eio_dirent *min = dents;

        /* the radix pre-pass ensures that the minimum element is in the first EIO_SORT_CUTOFF + 1 elements */
        for (i = size > EIO_SORT_FAST ? EIO_SORT_CUTOFF + 1 : size; --i; )
            if (EIO_DENT_CMP (dents [i], <, *min))
                min = &dents [i];

        /* swap elements 0 and j (minimum) */
        {
            eio_dirent tmp = *dents; *dents = *min; *min = tmp;
        }
    }

    /* then do standard insertion sort, assuming that all elements are >= dents [0] */
    {
        eio_dirent *i, *j;

        for (i = dents + 1; i < dents + size; ++i)
            {
                eio_dirent value = *i;

                for (j = i - 1; EIO_DENT_CMP (*j, >, value); --j)
                    j [1] = j [0];

                j [1] = value;
            }
    }
}

static void
eio_dent_sort (eio_dirent *dents, int size, signed char score_bits, eio_ino_t inode_bits)
{
    if (size <= 1)
        return; /* our insertion sort relies on size > 0 */

    /* first we use a radix sort, but only for dirs >= EIO_SORT_FAST */
    /* and stop sorting when the partitions are <= EIO_SORT_CUTOFF */
    eio_dent_radix_sort (dents, size, score_bits, inode_bits);

    /* use an insertion sort at the end, or for small arrays, */
    /* as insertion sort is more efficient for small partitions */
    eio_dent_insertion_sort (dents, size);
}

/* read a full directory */
static void
eio__scandir (eio_req *req, etp_worker *self)
{
    char *name, *names;
    int namesalloc = 4096 - sizeof (void *) * 4;
    int namesoffs = 0;
    int flags = req->int1;
    eio_dirent *dents = 0;
    int dentalloc = 128;
    int dentoffs = 0;
    eio_ino_t inode_bits = 0;
#ifdef _WIN32
    HANDLE dirp;
    WIN32_FIND_DATA entp;
#else
    DIR *dirp;
    EIO_STRUCT_DIRENT *entp;
#endif

    req->result = -1;

    if (!(flags & EIO_READDIR_DENTS))
        flags &= ~(EIO_READDIR_DIRS_FIRST | EIO_READDIR_STAT_ORDER);

#ifdef _WIN32
    {
        int len = strlen ((const char *)req->ptr1);
        char *path = malloc (MAX_PATH);
        const char *fmt;
        const char *reqpath = wd_expand (&self->tmpbuf, req->wd, req->ptr1);

        if (!len)
            fmt = "./*";
        else if (reqpath[len - 1] == '/' || reqpath[len - 1] == '\\')
            fmt = "%s*";
        else
            fmt = "%s/*";

        _snprintf (path, MAX_PATH, fmt, reqpath);
        dirp = FindFirstFile (path, &entp);
        free (path);

        if (dirp == INVALID_HANDLE_VALUE)
          {
              /* should steal _dosmaperr */
              switch (GetLastError ())
                  {
                      case ERROR_FILE_NOT_FOUND:
                          req->result = 0;
                          break;

                      case ERROR_INVALID_NAME:
                      case ERROR_PATH_NOT_FOUND:
                      case ERROR_NO_MORE_FILES:
                          errno = ENOENT;
                          break;

                      case ERROR_NOT_ENOUGH_MEMORY:
                          errno = ENOMEM;
                          break;

                      default:
                          errno = EINVAL;
                          break;
                  }

              return;
          }
    }
#else
    #if HAVE_AT
        {
            int fd = openat (WD2FD (req->wd), req->ptr1, O_CLOEXEC | O_RDONLY | O_DIRECTORY | O_NONBLOCK);

            if (fd < 0)
                return;

            dirp = fdopendir (fd);

            if (!dirp)
                {
                    silent_close (fd);
                    return;
                }
        }
    #else
        dirp = opendir (wd_expand (&self->tmpbuf, req->wd, req->ptr1));

        if (!dirp)
            return;
    #endif
#endif

    if (req->flags & EIO_FLAG_PTR1_FREE)
        free (req->ptr1);

    req->flags |= EIO_FLAG_PTR1_FREE | EIO_FLAG_PTR2_FREE;
    req->ptr1 = dents = flags ? malloc (dentalloc * sizeof (eio_dirent)) : 0;
    req->ptr2 = names = malloc (namesalloc);

    if (!names || (flags && !dents))
        return;

    for (;;)
        {
            int done;

#ifdef _WIN32
            done = !dirp;
#else
            errno = 0;
            entp = readdir (dirp);
            done = !entp;
#endif

            if (done)
                {
#ifndef _WIN32
                    int old_errno = errno;
                    closedir (dirp);
                    errno = old_errno;

                    if (errno)
                        break;
#endif

                    /* sort etc. */
                    req->int1   = flags;
                    req->result = dentoffs;

                    if (flags & EIO_READDIR_STAT_ORDER)
                        eio_dent_sort (dents, dentoffs, flags & EIO_READDIR_DIRS_FIRST ? 7 : 0, inode_bits);
                    else if (flags & EIO_READDIR_DIRS_FIRST)
                        if (flags & EIO_READDIR_FOUND_UNKNOWN)
                            eio_dent_sort (dents, dentoffs, 7, inode_bits); /* sort by score and inode */
                        else
                            {
                                /* in this case, all is known, and we just put dirs first and sort them */
                                eio_dirent *oth = dents + dentoffs;
                                eio_dirent *dir = dents;

                                /* now partition dirs to the front, and non-dirs to the back */
                                /* by walking from both sides and swapping if necessary */
                                while (oth > dir)
                                    {
                                        if (dir->type == EIO_DT_DIR)
                                            ++dir;
                                        else if ((--oth)->type == EIO_DT_DIR)
                                            {
                                                eio_dirent tmp = *dir; *dir = *oth; *oth = tmp;

                                                ++dir;
                                            }
                                    }

                                /* now sort the dirs only (dirs all have the same score) */
                                eio_dent_sort (dents, dir - dents, 0, inode_bits);
                            }

                    break;
                }

            /* now add the entry to our list(s) */
            name = D_NAME (entp);

            /* skip . and .. entries */
            if (name [0] != '.' || (name [1] && (name [1] != '.' || name [2])))
                {
                    int len = D_NAMLEN (entp) + 1;

                    while (ecb_expect_false (namesoffs + len > namesalloc))
                        {
                            namesalloc *= 2;
                            req->ptr2 = names = realloc (names, namesalloc);

                            if (!names)
                                break;
                        }

                    memcpy (names + namesoffs, name, len);

                    if (dents)
                        {
                            struct eio_dirent *ent;

                            if (ecb_expect_false (dentoffs == dentalloc))
                                {
                                    dentalloc *= 2;
                                    req->ptr1 = dents = realloc (dents, dentalloc * sizeof (eio_dirent));

                                    if (!dents)
                                        break;
                                }

                            ent = dents + dentoffs;

                            ent->nameofs = namesoffs; /* rather dirtily we store the offset in the pointer */
                            ent->namelen = len - 1;
                            ent->inode   = D_INO (entp);

                            inode_bits |= ent->inode;

                            switch (D_TYPE (entp))
                                {
                                    default:
                                        ent->type = EIO_DT_UNKNOWN;
                                        flags |= EIO_READDIR_FOUND_UNKNOWN;
                                        break;

                                    #ifdef DT_FIFO
                                        case DT_FIFO: ent->type = EIO_DT_FIFO; break;
                                    #endif
                                    #ifdef DT_CHR
                                        case DT_CHR:  ent->type = EIO_DT_CHR;  break;
                                    #endif
                                    #ifdef DT_MPC
                                        case DT_MPC:  ent->type = EIO_DT_MPC;  break;
                                    #endif
                                    #ifdef DT_DIR
                                        case DT_DIR:  ent->type = EIO_DT_DIR;  break;
                                    #endif
                                    #ifdef DT_NAM
                                        case DT_NAM:  ent->type = EIO_DT_NAM;  break;
                                    #endif
                                    #ifdef DT_BLK
                                        case DT_BLK:  ent->type = EIO_DT_BLK;  break;
                                    #endif
                                    #ifdef DT_MPB
                                        case DT_MPB:  ent->type = EIO_DT_MPB;  break;
                                    #endif
                                    #ifdef DT_REG
                                        case DT_REG:  ent->type = EIO_DT_REG;  break;
                                    #endif
                                    #ifdef DT_NWK
                                        case DT_NWK:  ent->type = EIO_DT_NWK;  break;
                                    #endif
                                    #ifdef DT_CMP
                                        case DT_CMP:  ent->type = EIO_DT_CMP;  break;
                                    #endif
                                    #ifdef DT_LNK
                                        case DT_LNK:  ent->type = EIO_DT_LNK;  break;
                                    #endif
                                    #ifdef DT_SOCK
                                        case DT_SOCK: ent->type = EIO_DT_SOCK; break;
                                    #endif
                                    #ifdef DT_DOOR
                                        case DT_DOOR: ent->type = EIO_DT_DOOR; break;
                                    #endif
                                    #ifdef DT_WHT
                                        case DT_WHT:  ent->type = EIO_DT_WHT;  break;
                                    #endif
                                }

                            ent->score = 7;

                            if (flags & EIO_READDIR_DIRS_FIRST)
                                {
                                    if (ent->type == EIO_DT_UNKNOWN)
                                        {
                                            if (*name == '.') /* leading dots are likely directories, and, in any case, rare */
                                                ent->score = 1;
                                            else if (!strchr (name, '.')) /* absence of dots indicate likely dirs */
                                                ent->score = len <= 2 ? 4 - len : len <= 4 ? 4 : len <= 7 ? 5 : 6; /* shorter == more likely dir, but avoid too many classes */
                                        }
                                    else if (ent->type == EIO_DT_DIR)
                                        ent->score = 0;
                                }
                        }

                    namesoffs += len;
                    ++dentoffs;
                }

            if (EIO_CANCELLED (req))
                {
                    errno = ECANCELED;
                    break;
                }

#ifdef _WIN32
            if (!FindNextFile (dirp, &entp))
                {
                    FindClose (dirp);
                    dirp = 0;
                }
#endif
        }
}

/*****************************************************************************/
/* working directory stuff */
/* various deficiencies in the posix 2008 api force us to */
/* keep the absolute path in string form at all times */
/* fuck yeah. */

#if !HAVE_AT

/* a bit like realpath, but usually faster because it doesn't have to return */
/* an absolute or canonical path */
static const char *
wd_expand (struct etp_tmpbuf *tmpbuf, eio_wd wd, const char *path)
{
    if (!wd || *path == '/')
        return path;

    if (path [0] == '.' && !path [1])
        return wd->str;

    {
        int l1 = wd->len;
        int l2 = strlen (path);

        char *res = etp_tmpbuf_get (tmpbuf, l1 + l2 + 2);

        memcpy (res, wd->str, l1);
        res [l1] = '/';
        memcpy (res + l1 + 1, path, l2 + 1);

        return res;
    }
}

#endif

static eio_wd
eio__wd_open_sync (struct etp_tmpbuf *tmpbuf, eio_wd wd, const char *path)
{
    int fd;
    eio_wd res;
    int len = eio__realpath (tmpbuf, wd, path);

    if (len < 0)
        return EIO_INVALID_WD;

#if HAVE_AT
    fd = openat (WD2FD (wd), path, EIO_O_PATH | O_DIRECTORY | O_NONBLOCK | O_CLOEXEC);

    /* 0 is a valid fd, but we use it for EIO_CWD, so in the very unlikely */
    /* case of fd 0 being available (almost certainly an a pplication bug) */
    /* make sure we use another fd value */
    #if EIO_CWD
        error EIO_CWD must be 0
    #endif
    if (ecb_expect_false (fd == 0))
        {
            int fd2 = fcntl (fd, F_DUPFD_CLOEXEC ? F_DUPFD_CLOEXEC : F_DUPFD);
            fcntl (fd2, F_SETFD, FD_CLOEXEC);
            eio__close (fd);
            fd = fd2;
        }

    if (fd < 0)
        return EIO_INVALID_WD;
#endif

    res = malloc (sizeof (*res) + len); /* one extra 0-byte */

#if HAVE_AT
    res->fd = fd;
#endif

    res->len = len;
    memcpy (res->str, tmpbuf->ptr, len);
    res->str [len] = 0;

    return res;
}

eio_wd
eio_wd_open_sync (eio_wd wd, const char *path)
{
    struct etp_tmpbuf tmpbuf = { 0 };
    wd = eio__wd_open_sync (&tmpbuf, wd, path);
    free (tmpbuf.ptr);

    return wd;
}

void
eio_wd_close_sync (eio_wd wd)
{
    if (wd != EIO_INVALID_WD && wd != EIO_CWD)
        {
            #if HAVE_AT
            eio__close (wd->fd);
            #endif
            free (wd);
        }
}

#if HAVE_AT

static int
eio__renameat2 (int olddirfd, const char *oldpath, int newdirfd, const char *newpath, unsigned int flags)
{
#if HAVE_RENAMEAT2
    return syscall (SYS_renameat2, olddirfd, oldpath, newdirfd, newpath, flags);
#else
    if (flags)
        return EIO_ENOSYS ();

    return renameat (olddirfd, oldpath, newdirfd, newpath);
#endif
}

/* they forgot these */

static int
eio__truncateat (int dirfd, const char *path, off_t length)
{
    int fd = openat (dirfd, path, O_WRONLY | O_CLOEXEC | O_NONBLOCK);
    int res;

    if (fd < 0)
        return fd;

    res = ftruncate (fd, length);
    silent_close (fd);
    return res;
}

static int
eio__statvfsat (int dirfd, const char *path, struct statvfs *buf)
{
    int fd = openat (dirfd, path, EIO_O_PATH | O_CLOEXEC | O_NONBLOCK);
    int res;

    if (fd < 0)
        return fd;

    res = fstatvfs (fd, buf);
    silent_close (fd);
    return res;
}

#endif

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

#define ALLOC(len)				\
    if (!req->ptr2)				\
        {						\
            X_LOCK (EIO_POOL->wrklock);		\
            req->flags |= EIO_FLAG_PTR2_FREE;		\
            X_UNLOCK (EIO_POOL->wrklock);		\
            req->ptr2 = malloc (len);			\
            if (!req->ptr2)				\
                {					\
                    errno       = ENOMEM;			\
                    req->result = -1;			\
                    goto alloc_fail;			\
                }					\
        }

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

static void
eio__slurp (int fd, eio_req *req)
{
    req->result = fd;

    if (fd < 0)
        return;

    if (req->offs < 0 || !req->size) /* do we need the size? */
        {
            off_t size = lseek (fd, 0, SEEK_END);

            if (req->offs < 0)
                req->offs += size;

            if (!req->size)
                req->size = size - req->offs;
        }

    ALLOC (req->size);
    req->result = pread (fd, req->ptr2, req->size, req->offs);

    silent_close (fd);

alloc_fail:
    ;
}

int ecb_cold
eio_init (void (*want_poll)(void), void (*done_poll)(void))
{
    eio_want_poll_cb = want_poll;
    eio_done_poll_cb = done_poll;

    return etp_init (EIO_POOL, 0, 0, 0);
}

ecb_inline void
eio_api_destroy (eio_req *req)
{
    free (req);
}

#define REQ(rtype)						\
    eio_req *req;                                                 \
                                                                                                                                \
    req = (eio_req *)calloc (1, sizeof *req);                     \
    if (!req)                                                     \
        return 0;                                                   \
                                                                                                                                \
    req->type    = rtype;                                         \
    req->pri     = pri;						\
    req->finish  = cb;						\
    req->data    = data;						\
    req->destroy = eio_api_destroy;

#define SEND eio_submit (req); return req

#define PATH							\
    req->flags |= EIO_FLAG_PTR1_FREE;				\
    req->ptr1 = strdup (path);					\
    if (!req->ptr1)						\
        {								\
            eio_api_destroy (req);					\
            return 0;							\
        }

#define SINGLEDOT(ptr) (0[(char *)(ptr)] == '.' && !1[(char *)(ptr)])

static void
eio_execute (etp_worker *self, eio_req *req)
{
#if HAVE_AT
    int dirfd;
#else
    const char *path;
#endif

    if (ecb_expect_false (EIO_CANCELLED (req)))
        {
            req->result  = -1;
            req->errorno = ECANCELED;
            return;
        }

    if (ecb_expect_false (req->wd == EIO_INVALID_WD))
        {
            req->result  = -1;
            req->errorno = ENOENT;
            return;
        }

    if (req->type >= EIO_OPEN)
        {
            #if HAVE_AT
                dirfd = WD2FD (req->wd);
            #else
                path = wd_expand (&self->tmpbuf, req->wd, req->ptr1);
            #endif
        }

    switch (req->type)
        {
            case EIO_WD_OPEN:   req->wd = eio__wd_open_sync (&self->tmpbuf, req->wd, req->ptr1);
                                                    req->result = req->wd == EIO_INVALID_WD ? -1 : 0;
                                                    break;
            case EIO_WD_CLOSE:  req->result = 0;
                                                    eio_wd_close_sync (req->wd); break;

            case EIO_SEEK:      eio__lseek (req); break;
            case EIO_READ:      ALLOC (req->size);
                                                    req->result = req->offs >= 0
                                                                            ? pread     (req->int1, req->ptr2, req->size, req->offs)
                                                                            : read      (req->int1, req->ptr2, req->size); break;
            case EIO_WRITE:     req->result = req->offs >= 0
                                                                            ? pwrite    (req->int1, req->ptr2, req->size, req->offs)
                                                                            : write     (req->int1, req->ptr2, req->size); break;

            case EIO_FCNTL:     req->result = fcntl     (req->int1, (int)          req->int2, req->ptr2); break;
            case EIO_IOCTL:     req->result = ioctl     (req->int1, (unsigned long)req->int2, req->ptr2); break;

            case EIO_READAHEAD: req->result = readahead     (req->int1, req->offs, req->size); break;
            case EIO_SENDFILE:  req->result = eio__sendfile (req->int1, req->int2, req->offs, req->size); break;

#if HAVE_AT

            case EIO_STAT:      ALLOC (sizeof (EIO_STRUCT_STAT));
                                                    req->result = fstatat   (dirfd, req->ptr1, (EIO_STRUCT_STAT *)req->ptr2, 0); break;
            case EIO_LSTAT:     ALLOC (sizeof (EIO_STRUCT_STAT));
                                                    req->result = fstatat   (dirfd, req->ptr1, (EIO_STRUCT_STAT *)req->ptr2, AT_SYMLINK_NOFOLLOW); break;
            case EIO_CHOWN:     req->result = fchownat  (dirfd, req->ptr1, req->int2, req->int3, 0); break;
            case EIO_CHMOD:     req->result = fchmodat  (dirfd, req->ptr1, (mode_t)req->int2, 0); break;
            case EIO_TRUNCATE:  req->result = eio__truncateat (dirfd, req->ptr1, req->offs); break;
            case EIO_OPEN:      req->result = openat    (dirfd, req->ptr1, req->int1, (mode_t)req->int2); break;
            case EIO_SLURP:     eio__slurp (  openat    (dirfd, req->ptr1, O_RDONLY | O_CLOEXEC), req); break;

            case EIO_UNLINK:    req->result = unlinkat  (dirfd, req->ptr1, 0); break;
            case EIO_RMDIR:     /* complications arise because "." cannot be removed, so we might have to expand */
                                                    req->result = req->wd && SINGLEDOT (req->ptr1)
                                                          ? rmdir (req->wd->str)
                                                          : unlinkat (dirfd, req->ptr1, AT_REMOVEDIR); break;
            case EIO_MKDIR:     req->result = mkdirat   (dirfd, req->ptr1, (mode_t)req->int2); break;
            case EIO_RENAME:    req->result = eio__renameat2 (
                                                        dirfd,
                                                        /* complications arise because "." cannot be renamed, so we might have to expand */
                                                        req->wd && SINGLEDOT (req->ptr1) ? req->wd->str : req->ptr1,
                                                        WD2FD ((eio_wd)req->int3),
                                                        req->ptr2,
                                                        req->int2
                                                    );
                                                    break;
            case EIO_LINK:      req->result = linkat    (dirfd, req->ptr1, WD2FD ((eio_wd)req->int3), req->ptr2, 0); break;
            case EIO_SYMLINK:   req->result = symlinkat (req->ptr1, dirfd, req->ptr2); break;
            case EIO_MKNOD:     req->result = mknodat   (dirfd, req->ptr1, (mode_t)req->int2, (dev_t)req->offs); break;
            case EIO_STATVFS:   ALLOC (sizeof (EIO_STRUCT_STATVFS));
                                                    req->result = eio__statvfsat (dirfd, req->ptr1, (EIO_STRUCT_STATVFS *)req->ptr2); break;
            case EIO_READLINK:  ALLOC (EIO_PATH_MAX);
                                                    req->result = readlinkat (dirfd, req->ptr1, req->ptr2, EIO_PATH_MAX);
                                                    if (req->result == EIO_PATH_MAX)
                                                        {
                                                            req->result = -1;
                                                            errno = ENAMETOOLONG;
                                                        }
                                                    break;
            case EIO_UTIME:
            case EIO_FUTIME:
                {
                    struct timespec ts[2];
                    struct timespec *times;

                    if (req->nv1 != -1. || req->nv2 != -1.)
                        {
                            ts[0].tv_sec  = req->nv1;
                            ts[0].tv_nsec = (req->nv1 - ts[0].tv_sec) * 1e9;
                            ts[1].tv_sec  = req->nv2;
                            ts[1].tv_nsec = (req->nv2 - ts[1].tv_sec) * 1e9;

                            times = ts;
                        }
                    else
                        times = 0;

                    req->result = req->type == EIO_FUTIME
                                                ? futimens  (req->int1, times)
                                                : utimensat (dirfd, req->ptr1, times, 0);
                }
                break;

#else

            case EIO_STAT:      ALLOC (sizeof (EIO_STRUCT_STAT));
                                                    req->result = stat      (path     , (EIO_STRUCT_STAT *)req->ptr2); break;
            case EIO_LSTAT:     ALLOC (sizeof (EIO_STRUCT_STAT));
                                                    req->result = lstat     (path     , (EIO_STRUCT_STAT *)req->ptr2); break;
            case EIO_CHOWN:     req->result = chown     (path     , req->int2, req->int3); break;
            case EIO_CHMOD:     req->result = chmod     (path     , (mode_t)req->int2); break;
            case EIO_TRUNCATE:  req->result = truncate  (path     , req->offs); break;
            case EIO_OPEN:      req->result = open      (path     , req->int1, (mode_t)req->int2); break;
            case EIO_SLURP:     eio__slurp (  open      (path     , O_RDONLY | O_CLOEXEC), req); break;

            case EIO_UNLINK:    req->result = unlink    (path     ); break;
            case EIO_RMDIR:     req->result = rmdir     (path     ); break;
            case EIO_MKDIR:     req->result = mkdir     (path     , (mode_t)req->int2); break;
            case EIO_RENAME:    req->result = req->int2 ? EIO_ENOSYS () : rename (path, req->ptr2); break;
            case EIO_LINK:      req->result = link      (path     , req->ptr2); break;
            case EIO_SYMLINK:   req->result = symlink   (path     , req->ptr2); break;
            case EIO_MKNOD:     req->result = mknod     (path     , (mode_t)req->int2, (dev_t)req->offs); break;
            case EIO_STATVFS:   ALLOC (sizeof (EIO_STRUCT_STATVFS));
                                                    req->result = statvfs   (path     , (EIO_STRUCT_STATVFS *)req->ptr2); break;
            case EIO_READLINK:  ALLOC (EIO_PATH_MAX);
                                                    req->result = readlink (path, req->ptr2, EIO_PATH_MAX);
                                                    if (req->result == EIO_PATH_MAX)
                                                        {
                                                            req->result = -1;
                                                            errno = ENAMETOOLONG;
                                                        }
                                                    break;

            case EIO_UTIME:
            case EIO_FUTIME:
                {
                    struct timeval tv[2];
                    struct timeval *times;

                    if (req->nv1 != -1. || req->nv2 != -1.)
                        {
                            tv[0].tv_sec  = req->nv1;
                            tv[0].tv_usec = (req->nv1 - tv[0].tv_sec) * 1e6;
                            tv[1].tv_sec  = req->nv2;
                            tv[1].tv_usec = (req->nv2 - tv[1].tv_sec) * 1e6;

                            times = tv;
                        }
                    else
                        times = 0;

                    req->result = req->type == EIO_FUTIME
                                                ? futimes (req->int1, times)
                                                : utimes  (req->ptr1, times);
                }
                break;

#endif

            case EIO_REALPATH:  if (0 <= (req->result = eio__realpath (&self->tmpbuf, req->wd, req->ptr1)))
                                                        {
                                                            ALLOC (req->result);
                                                            memcpy (req->ptr2, self->tmpbuf.ptr, req->result);
                                                        }
                                                      break;

            case EIO_FSTAT:     ALLOC (sizeof (EIO_STRUCT_STAT));
                                                    req->result = fstat     (req->int1, (EIO_STRUCT_STAT *)req->ptr2); break;

            case EIO_FSTATVFS:  ALLOC (sizeof (EIO_STRUCT_STATVFS));
                                                    req->result = fstatvfs  (req->int1, (EIO_STRUCT_STATVFS *)req->ptr2); break;

            case EIO_FCHOWN:    req->result = fchown    (req->int1, req->int2, req->int3); break;
            case EIO_FCHMOD:    req->result = fchmod    (req->int1, (mode_t)req->int2); break;
            case EIO_FTRUNCATE: req->result = ftruncate (req->int1, req->offs); break;

            case EIO_CLOSE:     req->result = eio__close (req->int1); break;
            case EIO_DUP2:      req->result = dup2      (req->int1, req->int2); break;
            case EIO_SYNC:      req->result = 0; sync (); break;
            case EIO_FSYNC:     req->result = fsync     (req->int1); break;
            case EIO_FDATASYNC: req->result = fdatasync (req->int1); break;
            case EIO_SYNCFS:    req->result = eio__syncfs (req->int1); break;
            case EIO_SYNC_FILE_RANGE: req->result = eio__sync_file_range (req->int1, req->offs, req->size, req->int2); break;
            case EIO_MSYNC:     req->result = eio__msync (req->ptr2, req->size, req->int1); break;
            case EIO_MTOUCH:    req->result = eio__mtouch (req); break;
            case EIO_MLOCK:     req->result = eio__mlock (req->ptr2, req->size); break;
            case EIO_MLOCKALL:  req->result = eio__mlockall (req->int1); break;
            case EIO_FALLOCATE: req->result = eio__fallocate (req->int1, req->int2, req->offs, req->size); break;

            case EIO_READDIR:   eio__scandir (req, self); break;

            case EIO_BUSY:
#ifdef _WIN32
		Sleep (req->nv1 * 1e3);
#else
                {
                    struct timeval tv;

                    tv.tv_sec  = req->nv1;
                    tv.tv_usec = (req->nv1 - tv.tv_sec) * 1e6;

                    req->result = select (0, 0, 0, 0, &tv);
                }
#endif
                break;

#if 0
            case EIO_GROUP:
                abort (); /* handled in eio_request */
#endif

            case EIO_NOP:
                req->result = 0;
                break;

            case EIO_CUSTOM:
                req->feed (req);
                break;

            default:
                req->result = EIO_ENOSYS ();
                break;
        }

alloc_fail:
    req->errorno = errno;
}

#ifndef EIO_NO_WRAPPERS

eio_req *eio_wd_open (const char *path, int pri, eio_cb cb, void *data)
{
    REQ (EIO_WD_OPEN); PATH; SEND;
}

eio_req *eio_wd_close (eio_wd wd, int pri, eio_cb cb, void *data)
{
    REQ (EIO_WD_CLOSE); req->wd = wd; SEND;
}

eio_req *eio_nop (int pri, eio_cb cb, void *data)
{
    REQ (EIO_NOP); SEND;
}

eio_req *eio_busy (double delay, int pri, eio_cb cb, void *data)
{
    REQ (EIO_BUSY); req->nv1 = delay; SEND;
}

eio_req *eio_sync (int pri, eio_cb cb, void *data)
{
    REQ (EIO_SYNC); SEND;
}

eio_req *eio_fsync (int fd, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FSYNC); req->int1 = fd; SEND;
}

eio_req *eio_msync (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data)
{
    REQ (EIO_MSYNC); req->ptr2 = addr; req->size = length; req->int1 = flags; SEND;
}

eio_req *eio_fdatasync (int fd, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FDATASYNC); req->int1 = fd; SEND;
}

eio_req *eio_syncfs (int fd, int pri, eio_cb cb, void *data)
{
    REQ (EIO_SYNCFS); req->int1 = fd; SEND;
}

eio_req *eio_sync_file_range (int fd, off_t offset, size_t nbytes, unsigned int flags, int pri, eio_cb cb, void *data)
{
    REQ (EIO_SYNC_FILE_RANGE); req->int1 = fd; req->offs = offset; req->size = nbytes; req->int2 = flags; SEND;
}

eio_req *eio_mtouch (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data)
{
    REQ (EIO_MTOUCH); req->ptr2 = addr; req->size = length; req->int1 = flags; SEND;
}

eio_req *eio_mlock (void *addr, size_t length, int pri, eio_cb cb, void *data)
{
    REQ (EIO_MLOCK); req->ptr2 = addr; req->size = length; SEND;
}

eio_req *eio_mlockall (int flags, int pri, eio_cb cb, void *data)
{
    REQ (EIO_MLOCKALL); req->int1 = flags; SEND;
}

eio_req *eio_fallocate (int fd, int mode, off_t offset, size_t len, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FALLOCATE); req->int1 = fd; req->int2 = mode; req->offs = offset; req->size = len; SEND;
}

eio_req *eio_close (int fd, int pri, eio_cb cb, void *data)
{
    REQ (EIO_CLOSE); req->int1 = fd; SEND;
}

eio_req *eio_readahead (int fd, off_t offset, size_t length, int pri, eio_cb cb, void *data)
{
    REQ (EIO_READAHEAD); req->int1 = fd; req->offs = offset; req->size = length; SEND;
}

eio_req *eio_seek (int fd, off_t offset, int whence, int pri, eio_cb cb, void *data)
{
    REQ (EIO_SEEK); req->int1 = fd; req->offs = offset; req->int2 = whence; SEND;
}

eio_req *eio_read (int fd, void *buf, size_t length, off_t offset, int pri, eio_cb cb, void *data)
{
    REQ (EIO_READ); req->int1 = fd; req->offs = offset; req->size = length; req->ptr2 = buf; SEND;
}

eio_req *eio_write (int fd, void *buf, size_t length, off_t offset, int pri, eio_cb cb, void *data)
{
    REQ (EIO_WRITE); req->int1 = fd; req->offs = offset; req->size = length; req->ptr2 = buf; SEND;
}

eio_req *eio_fcntl (int fd, int cmd, void *arg, int pri, eio_cb cb, void *data)
{
    REQ (EIO_IOCTL); req->int1 = fd; req->int2 = cmd; req->ptr2 = arg; SEND;
}

eio_req *eio_ioctl (int fd, unsigned long request, void *buf, int pri, eio_cb cb, void *data)
{
    REQ (EIO_IOCTL); req->int1 = fd; req->int2 = request; req->ptr2 = buf; SEND;
}

eio_req *eio_fstat (int fd, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FSTAT); req->int1 = fd; SEND;
}

eio_req *eio_fstatvfs (int fd, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FSTATVFS); req->int1 = fd; SEND;
}

eio_req *eio_futime (int fd, double atime, double mtime, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FUTIME); req->int1 = fd; req->nv1 = atime; req->nv2 = mtime; SEND;
}

eio_req *eio_ftruncate (int fd, off_t offset, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FTRUNCATE); req->int1 = fd; req->offs = offset; SEND;
}

eio_req *eio_fchmod (int fd, mode_t mode, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FCHMOD); req->int1 = fd; req->int2 = (long)mode; SEND;
}

eio_req *eio_fchown (int fd, eio_uid_t uid, eio_gid_t gid, int pri, eio_cb cb, void *data)
{
    REQ (EIO_FCHOWN); req->int1 = fd; req->int2 = (long)uid; req->int3 = (long)gid; SEND;
}

eio_req *eio_dup2 (int fd, int fd2, int pri, eio_cb cb, void *data)
{
    REQ (EIO_DUP2); req->int1 = fd; req->int2 = fd2; SEND;
}

eio_req *eio_sendfile (int out_fd, int in_fd, off_t in_offset, size_t length, int pri, eio_cb cb, void *data)
{
    REQ (EIO_SENDFILE); req->int1 = out_fd; req->int2 = in_fd; req->offs = in_offset; req->size = length; SEND;
}

eio_req *eio_open (const char *path, int flags, mode_t mode, int pri, eio_cb cb, void *data)
{
    REQ (EIO_OPEN); PATH; req->int1 = flags; req->int2 = (long)mode; SEND;
}

eio_req *eio_utime (const char *path, double atime, double mtime, int pri, eio_cb cb, void *data)
{
    REQ (EIO_UTIME); PATH; req->nv1 = atime; req->nv2 = mtime; SEND;
}

eio_req *eio_truncate (const char *path, off_t offset, int pri, eio_cb cb, void *data)
{
    REQ (EIO_TRUNCATE); PATH; req->offs = offset; SEND;
}

eio_req *eio_chown (const char *path, eio_uid_t uid, eio_gid_t gid, int pri, eio_cb cb, void *data)
{
    REQ (EIO_CHOWN); PATH; req->int2 = (long)uid; req->int3 = (long)gid; SEND;
}

eio_req *eio_chmod (const char *path, mode_t mode, int pri, eio_cb cb, void *data)
{
    REQ (EIO_CHMOD); PATH; req->int2 = (long)mode; SEND;
}

eio_req *eio_mkdir (const char *path, mode_t mode, int pri, eio_cb cb, void *data)
{
    REQ (EIO_MKDIR); PATH; req->int2 = (long)mode; SEND;
}

static eio_req *
eio__1path (int type, const char *path, int pri, eio_cb cb, void *data)
{
    REQ (type); PATH; SEND;
}

eio_req *eio_readlink (const char *path, int pri, eio_cb cb, void *data)
{
    return eio__1path (EIO_READLINK, path, pri, cb, data);
}

eio_req *eio_realpath (const char *path, int pri, eio_cb cb, void *data)
{
    return eio__1path (EIO_REALPATH, path, pri, cb, data);
}

eio_req *eio_stat (const char *path, int pri, eio_cb cb, void *data)
{
    return eio__1path (EIO_STAT, path, pri, cb, data);
}

eio_req *eio_lstat (const char *path, int pri, eio_cb cb, void *data)
{
    return eio__1path (EIO_LSTAT, path, pri, cb, data);
}

eio_req *eio_statvfs (const char *path, int pri, eio_cb cb, void *data)
{
    return eio__1path (EIO_STATVFS, path, pri, cb, data);
}

eio_req *eio_unlink (const char *path, int pri, eio_cb cb, void *data)
{
    return eio__1path (EIO_UNLINK, path, pri, cb, data);
}

eio_req *eio_rmdir (const char *path, int pri, eio_cb cb, void *data)
{
    return eio__1path (EIO_RMDIR, path, pri, cb, data);
}

eio_req *eio_readdir (const char *path, int flags, int pri, eio_cb cb, void *data)
{
    REQ (EIO_READDIR); PATH; req->int1 = flags; SEND;
}

eio_req *eio_mknod (const char *path, mode_t mode, dev_t dev, int pri, eio_cb cb, void *data)
{
    REQ (EIO_MKNOD); PATH; req->int2 = (long)mode; req->offs = (off_t)dev; SEND;
}

static eio_req *
eio__2path (int type, const char *path, const char *new_path, int pri, eio_cb cb, void *data)
{
    REQ (type); PATH;

    req->flags |= EIO_FLAG_PTR2_FREE;
    req->ptr2 = strdup (new_path);
    if (!req->ptr2)
        {
            eio_api_destroy (req);
            return 0;
        }

    SEND;
}

eio_req *eio_link (const char *path, const char *new_path, int pri, eio_cb cb, void *data)
{
    return eio__2path (EIO_LINK, path, new_path, pri, cb, data);
}

eio_req *eio_symlink (const char *path, const char *new_path, int pri, eio_cb cb, void *data)
{
    return eio__2path (EIO_SYMLINK, path, new_path, pri, cb, data);
}

eio_req *eio_rename (const char *path, const char *new_path, int pri, eio_cb cb, void *data)
{
    return eio__2path (EIO_RENAME, path, new_path, pri, cb, data);
}

eio_req *eio_slurp (const char *path, void *buf, size_t length, off_t offset, int pri, eio_cb cb, void *data)
{
    REQ (EIO_SLURP); PATH; req->offs = offset; req->size = length; req->ptr2 = buf; SEND;
}

eio_req *eio_custom (void (*execute)(eio_req *), int pri, eio_cb cb, void *data)
{
    REQ (EIO_CUSTOM); req->feed = execute; SEND;
}

#endif

eio_req *eio_grp (eio_cb cb, void *data)
{
    const int pri = EIO_PRI_MAX;

    REQ (EIO_GROUP); SEND;
}

#undef REQ
#undef PATH
#undef SEND

/*****************************************************************************/
/* grp functions */

void
eio_grp_feed (eio_req *grp, void (*feed)(eio_req *req), int limit)
{
    grp->int2 = limit;
    grp->feed = feed;

    grp_try_feed (grp);
}

void
eio_grp_limit (eio_req *grp, int limit)
{
    grp->int2 = limit;

    grp_try_feed (grp);
}

void
eio_grp_add (eio_req *grp, eio_req *req)
{
    assert (("cannot add requests to IO::AIO::GRP after the group finished", grp->int1 != 2));

    grp->flags |= ETP_FLAG_GROUPADD;

    ++grp->size;
    req->grp = grp;

    req->grp_prev = 0;
    req->grp_next = grp->grp_first;

    if (grp->grp_first)
        grp->grp_first->grp_prev = req;

    grp->grp_first = req;
}

/*****************************************************************************/
/* misc garbage */

eio_ssize_t
eio_sendfile_sync (int ofd, int ifd, off_t offset, size_t count)
{
    return eio__sendfile (ofd, ifd, offset, count);
}

int eio_mlockall_sync (int flags)
{
    return eio__mlockall (flags);
}