/*
     This file is part of GNUnet.
     Copyright (C) 2001--2013, 2016 GNUnet e.V.

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
*/
/**
 * @file util/disk.c
 * @brief disk IO convenience methods
 * @author Christian Grothoff
 * @author Nils Durner
 */
#include "platform.h"
#include "disk.h"
#include "gnunet_strings_lib.h"
#include "gnunet_disk_lib.h"

#define LOG(kind,...) GNUNET_log_from (kind, "util-disk", __VA_ARGS__)

#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util-disk", syscall)

#define LOG_STRERROR_FILE(kind,syscall,filename) GNUNET_log_from_strerror_file (kind, "util-disk", syscall, filename)

/**
 * Block size for IO for copying files.
 */
#define COPY_BLK_SIZE 65536

#include <sys/types.h>
#if HAVE_SYS_VFS_H
#include <sys/vfs.h>
#endif
#if HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#if HAVE_SYS_MOUNT_H
#include <sys/mount.h>
#endif
#if HAVE_SYS_STATVFS_H
#include <sys/statvfs.h>
#endif

#ifndef S_ISLNK
#define  	_IFMT		0170000 /* type of file */
#define  	_IFLNK		0120000 /* symbolic link */
#define  S_ISLNK(m)	(((m)&_IFMT) == _IFLNK)
#endif


/**
 * Handle used to manage a pipe.
 */
struct GNUNET_DISK_PipeHandle
{
  /**
   * File descriptors for the pipe.
   * One or both of them could be NULL.
   */
  struct GNUNET_DISK_FileHandle *fd[2];
};


/**
 * Closure for the recursion to determine the file size
 * of a directory.
 */
struct GetFileSizeData
{
  /**
   * Set to the total file size.
   */
  uint64_t total;

  /**
   * GNUNET_YES if symbolic links should be included.
   */
  int include_sym_links;

  /**
   * GNUNET_YES if mode is file-only (return total == -1 for directories).
   */
  int single_file_mode;
};


#ifndef MINGW
/**
 * Translate GNUnet-internal permission bitmap to UNIX file
 * access permission bitmap.
 *
 * @param perm file permissions, GNUnet style
 * @return file permissions, UNIX style
 */
static int
translate_unix_perms (enum GNUNET_DISK_AccessPermissions perm)
{
  int mode;

  mode = 0;
  if (perm & GNUNET_DISK_PERM_USER_READ)
    mode |= S_IRUSR;
  if (perm & GNUNET_DISK_PERM_USER_WRITE)
    mode |= S_IWUSR;
  if (perm & GNUNET_DISK_PERM_USER_EXEC)
    mode |= S_IXUSR;
  if (perm & GNUNET_DISK_PERM_GROUP_READ)
    mode |= S_IRGRP;
  if (perm & GNUNET_DISK_PERM_GROUP_WRITE)
    mode |= S_IWGRP;
  if (perm & GNUNET_DISK_PERM_GROUP_EXEC)
    mode |= S_IXGRP;
  if (perm & GNUNET_DISK_PERM_OTHER_READ)
    mode |= S_IROTH;
  if (perm & GNUNET_DISK_PERM_OTHER_WRITE)
    mode |= S_IWOTH;
  if (perm & GNUNET_DISK_PERM_OTHER_EXEC)
    mode |= S_IXOTH;

  return mode;
}
#endif


/**
 * Iterate over all files in the given directory and
 * accumulate their size.
 *
 * @param cls closure of type `struct GetFileSizeData`
 * @param fn current filename we are looking at
 * @return #GNUNET_SYSERR on serious errors, otherwise #GNUNET_OK
 */
static int
getSizeRec (void *cls, const char *fn)
{
  struct GetFileSizeData *gfsd = cls;

#if defined (HAVE_STAT64) && !(defined (_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS == 64)
  STRUCT_STAT64 buf;

  if (0 != STAT64 (fn, &buf))
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_DEBUG, "stat64", fn);
    return GNUNET_SYSERR;
  }
#else
  struct stat buf;

  if (0 != STAT (fn, &buf))
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_DEBUG, "stat", fn);
    return GNUNET_SYSERR;
  }
#endif
  if ((S_ISDIR (buf.st_mode)) && (gfsd->single_file_mode == GNUNET_YES))
  {
    errno = EISDIR;
    return GNUNET_SYSERR;
  }
  if ((!S_ISLNK (buf.st_mode)) || (gfsd->include_sym_links == GNUNET_YES))
    gfsd->total += buf.st_size;
  if ((S_ISDIR (buf.st_mode)) && (0 == ACCESS (fn, X_OK)) &&
      ((!S_ISLNK (buf.st_mode)) || (gfsd->include_sym_links == GNUNET_YES)))
  {
    if (GNUNET_SYSERR == GNUNET_DISK_directory_scan (fn, &getSizeRec, gfsd))
      return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}


/**
 * Checks whether a handle is invalid
 *
 * @param h handle to check
 * @return #GNUNET_YES if invalid, #GNUNET_NO if valid
 */
int
GNUNET_DISK_handle_invalid (const struct GNUNET_DISK_FileHandle *h)
{
#ifdef MINGW
  return ((!h) || (h->h == INVALID_HANDLE_VALUE)) ? GNUNET_YES : GNUNET_NO;
#else
  return ((!h) || (h->fd == -1)) ? GNUNET_YES : GNUNET_NO;
#endif
}

/**
 * Get the size of an open file.
 *
 * @param fh open file handle
 * @param size where to write size of the file
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
 */
int
GNUNET_DISK_file_handle_size (struct GNUNET_DISK_FileHandle *fh,
			      off_t *size)
{
#if WINDOWS
  BOOL b;
  LARGE_INTEGER li;
  b = GetFileSizeEx (fh->h, &li);
  if (!b)
  {
    SetErrnoFromWinError (GetLastError ());
    return GNUNET_SYSERR;
  }
  *size = (off_t) li.QuadPart;
#else
  struct stat sbuf;

  if (0 != FSTAT (fh->fd, &sbuf))
    return GNUNET_SYSERR;
  *size = sbuf.st_size;
#endif
  return GNUNET_OK;
}


/**
 * Move the read/write pointer in a file
 *
 * @param h handle of an open file
 * @param offset position to move to
 * @param whence specification to which position the offset parameter relates to
 * @return the new position on success, #GNUNET_SYSERR otherwise
 */
off_t
GNUNET_DISK_file_seek (const struct GNUNET_DISK_FileHandle * h, off_t offset,
                       enum GNUNET_DISK_Seek whence)
{
  if (h == NULL)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifdef MINGW
  LARGE_INTEGER li;
  LARGE_INTEGER new_pos;
  BOOL b;

  static DWORD t[] = { FILE_BEGIN, FILE_CURRENT, FILE_END };
  li.QuadPart = offset;

  b = SetFilePointerEx (h->h, li, &new_pos, t[whence]);
  if (b == 0)
  {
    SetErrnoFromWinError (GetLastError ());
    return GNUNET_SYSERR;
  }
  return (off_t) new_pos.QuadPart;
#else
  static int t[] = { SEEK_SET, SEEK_CUR, SEEK_END };

  return lseek (h->fd, offset, t[whence]);
#endif
}


/**
 * Get the size of the file (or directory) of the given file (in
 * bytes).
 *
 * @param filename name of the file or directory
 * @param size set to the size of the file (or,
 *             in the case of directories, the sum
 *             of all sizes of files in the directory)
 * @param include_symbolic_links should symbolic links be
 *        included?
 * @param single_file_mode #GNUNET_YES to only get size of one file
 *        and return #GNUNET_SYSERR for directories.
 * @return #GNUNET_SYSERR on error, #GNUNET_OK on success
 */
int
GNUNET_DISK_file_size (const char *filename,
		       uint64_t * size,
                       int include_symbolic_links,
		       int single_file_mode)
{
  struct GetFileSizeData gfsd;
  int ret;

  GNUNET_assert (size != NULL);
  gfsd.total = 0;
  gfsd.include_sym_links = include_symbolic_links;
  gfsd.single_file_mode = single_file_mode;
  ret = getSizeRec (&gfsd, filename);
  *size = gfsd.total;
  return ret;
}


/**
 * Obtain some unique identifiers for the given file
 * that can be used to identify it in the local system.
 * This function is used between GNUnet processes to
 * quickly check if two files with the same absolute path
 * are actually identical.  The two processes represent
 * the same peer but may communicate over the network
 * (and the file may be on an NFS volume).  This function
 * may not be supported on all operating systems.
 *
 * @param filename name of the file
 * @param dev set to the device ID
 * @param ino set to the inode ID
 * @return #GNUNET_OK on success
 */
int
GNUNET_DISK_file_get_identifiers (const char *filename, uint64_t * dev,
                                  uint64_t * ino)
{
#if WINDOWS
  {
    // FIXME NILS: test this
    struct GNUNET_DISK_FileHandle *fh;
    BY_HANDLE_FILE_INFORMATION info;
    int succ;

    fh = GNUNET_DISK_file_open (filename,
                                GNUNET_DISK_OPEN_READ,
                                GNUNET_DISK_PERM_NONE);
    if (NULL == fh)
      return GNUNET_SYSERR;
    succ = GetFileInformationByHandle (fh->h, &info);
    GNUNET_DISK_file_close (fh);
    if (!succ)
    {
      return GNUNET_SYSERR;
    }
    *dev = info.dwVolumeSerialNumber;
    *ino = ((((uint64_t) info.nFileIndexHigh) << (sizeof (DWORD) * 8)) | info.nFileIndexLow);
  }
#else /* !WINDOWS */
#if HAVE_STAT
  {
    struct stat sbuf;

    if (0 != stat (filename, &sbuf))
    {
      return GNUNET_SYSERR;
    }
    *ino = (uint64_t) sbuf.st_ino;
  }
#else
  *ino = 0;
#endif
#if HAVE_STATVFS
  {
    struct statvfs fbuf;

    if (0 != statvfs (filename, &fbuf))
    {
      return GNUNET_SYSERR;
    }
    *dev = (uint64_t) fbuf.f_fsid;
  }
#elif HAVE_STATFS
  {
    struct statfs fbuf;

    if (0 != statfs (filename, &fbuf))
    {
      return GNUNET_SYSERR;
    }
    *dev = ((uint64_t) fbuf.f_fsid.val[0]) << 32 ||
        ((uint64_t) fbuf.f_fsid.val[1]);
  }
#else
  *dev = 0;
#endif
#endif /* !WINDOWS */
  return GNUNET_OK;
}


/**
 * Create the name for a temporary file or directory from a template.
 *
 * @param t template (without XXXXX or "/tmp/")
 * @return name ready for passing to 'mktemp' or 'mkdtemp', NULL on error
 */
static char *
mktemp_name (const char *t)
{
  const char *tmpdir;
  char *tmpl;
  char *fn;

  if ((t[0] != '/') && (t[0] != '\\')
#if WINDOWS
      && !(isalpha ((int) t[0]) && (t[0] != '\0') && (t[1] == ':'))
#endif
      )
  {
    /* FIXME: This uses system codepage on W32, not UTF-8 */
    tmpdir = getenv ("TMPDIR");
    if (NULL == tmpdir)
      tmpdir = getenv ("TMP");
    if (NULL == tmpdir)
      tmpdir = getenv ("TEMP");
    if (NULL == tmpdir)
      tmpdir = "/tmp";
    GNUNET_asprintf (&tmpl, "%s/%s%s", tmpdir, t, "XXXXXX");
  }
  else
  {
    GNUNET_asprintf (&tmpl, "%s%s", t, "XXXXXX");
  }
#ifdef MINGW
  fn = (char *) GNUNET_malloc (MAX_PATH + 1);
  if (ERROR_SUCCESS != plibc_conv_to_win_path (tmpl, fn))
  {
    GNUNET_free (fn);
    GNUNET_free (tmpl);
    return NULL;
  }
  GNUNET_free (tmpl);
#else
  fn = tmpl;
#endif
  return fn;
}


#if WINDOWS
static char *
mkdtemp (char *fn)
{
  char *random_fn;
  char *tfn;

  while (1)
  {
    tfn = GNUNET_strdup (fn);
    random_fn = _mktemp (tfn);
    if (NULL == random_fn)
    {
      GNUNET_free (tfn);
      return NULL;
    }
    /* FIXME: assume fn to be UTF-8-encoded and do the right thing */
    if (0 == CreateDirectoryA (tfn, NULL))
    {
      DWORD error = GetLastError ();
      GNUNET_free (tfn);
      if (ERROR_ALREADY_EXISTS == error)
        continue;
      return NULL;
    }
    break;
  }
  strcpy (fn, tfn);
  return fn;
}

/**
 * Update POSIX permissions mask of a file on disk.  If both argumets
 * are #GNUNET_NO, the file is made world-read-write-executable (777).
 * Does nothing on W32.
 *
 * @param fn name of the file to update
 * @param require_uid_match #GNUNET_YES means 700
 * @param require_gid_match #GNUNET_YES means 770 unless @a require_uid_match is set
 */
void
GNUNET_DISK_fix_permissions (const char *fn,
                             int require_uid_match,
                             int require_gid_match)
{
  /* nothing on W32 */
}

#else

/**
 * Update POSIX permissions mask of a file on disk.  If both argumets
 * are #GNUNET_NO, the file is made world-read-write-executable (777).
 *
 * @param fn name of the file to update
 * @param require_uid_match #GNUNET_YES means 700
 * @param require_gid_match #GNUNET_YES means 770 unless @a require_uid_match is set
 */
void
GNUNET_DISK_fix_permissions (const char *fn,
                             int require_uid_match,
                             int require_gid_match)
{
  mode_t mode;

  if (GNUNET_YES == require_uid_match)
    mode = S_IRUSR | S_IWUSR | S_IXUSR;
  else if (GNUNET_YES == require_gid_match)
    mode = S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP;
  else
    mode = S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH;
  if (0 != chmod (fn, mode))
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
                              "chmod",
                              fn);
}

#endif

/**
 * Create an (empty) temporary directory on disk.  If the given name is not
 * an absolute path, the current 'TMPDIR' will be prepended.  In any case,
 * 6 random characters will be appended to the name to create a unique
 * filename.
 *
 * @param t component to use for the name;
 *        does NOT contain "XXXXXX" or "/tmp/".
 * @return NULL on error, otherwise name of fresh
 *         file on disk in directory for temporary files
 */
char *
GNUNET_DISK_mkdtemp (const char *t)
{
  char *fn;
  mode_t omask;

  omask = umask (S_IWGRP | S_IWOTH | S_IRGRP | S_IROTH);
  fn = mktemp_name (t);
  if (fn != mkdtemp (fn))
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "mkdtemp", fn);
    GNUNET_free (fn);
    umask (omask);
    return NULL;
  }
  umask (omask);
  return fn;
}


/**
 * Move a file out of the way (create a backup) by
 * renaming it to "orig.NUM~" where NUM is the smallest
 * number that is not used yet.
 *
 * @param fil name of the file to back up
 */
void
GNUNET_DISK_file_backup (const char *fil)
{
  size_t slen;
  char *target;
  unsigned int num;

  slen = strlen (fil) + 20;
  target = GNUNET_malloc (slen);
  num = 0;
  do
  {
    GNUNET_snprintf (target, slen,
		     "%s.%u~",
		     fil,
		     num++);
  } while (0 == access (target, F_OK));
  if (0 != rename (fil, target))
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
			      "rename",
			      fil);
  GNUNET_free (target);
}


/**
 * Create an (empty) temporary file on disk.  If the given name is not
 * an absolute path, the current 'TMPDIR' will be prepended.  In any case,
 * 6 random characters will be appended to the name to create a unique
 * filename.
 *
 * @param t component to use for the name;
 *        does NOT contain "XXXXXX" or "/tmp/".
 * @return NULL on error, otherwise name of fresh
 *         file on disk in directory for temporary files
 */
char *
GNUNET_DISK_mktemp (const char *t)
{
  int fd;
  char *fn;
  mode_t omask;

  omask = umask (S_IWGRP | S_IWOTH | S_IRGRP | S_IROTH);
  fn = mktemp_name (t);
  if (-1 == (fd = mkstemp (fn)))
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "mkstemp", fn);
    GNUNET_free (fn);
    umask (omask);
    return NULL;
  }
  umask (omask);
  if (0 != CLOSE (fd))
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "close", fn);
  return fn;
}


/**
 * Test if @a fil is a directory and listable. Optionally, also check if the
 * directory is readable.  Will not print an error message if the directory does
 * not exist.  Will log errors if #GNUNET_SYSERR is returned (i.e., a file exists
 * with the same name).
 *
 * @param fil filename to test
 * @param is_readable #GNUNET_YES to additionally check if @a fil is readable;
 *          #GNUNET_NO to disable this check
 * @return #GNUNET_YES if yes, #GNUNET_NO if not; #GNUNET_SYSERR if it
 *           does not exist or stat'ed
 */
int
GNUNET_DISK_directory_test (const char *fil, int is_readable)
{
  struct stat filestat;
  int ret;

  ret = STAT (fil, &filestat);
  if (ret != 0)
  {
    if (errno != ENOENT)
      LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "stat", fil);
    return GNUNET_SYSERR;
  }
  if (!S_ISDIR (filestat.st_mode))
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "A file already exits with the same name %s\n", fil);
    return GNUNET_NO;
  }
  if (GNUNET_YES == is_readable)
    ret = ACCESS (fil, R_OK | X_OK);
  else
    ret = ACCESS (fil, X_OK);
  if (ret < 0)
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "access", fil);
    return GNUNET_NO;
  }
  return GNUNET_YES;
}


/**
 * Check that fil corresponds to a filename
 * (of a file that exists and that is not a directory).
 *
 * @param fil filename to check
 * @return #GNUNET_YES if yes, #GNUNET_NO if not a file, #GNUNET_SYSERR if something
 * else (will print an error message in that case, too).
 */
int
GNUNET_DISK_file_test (const char *fil)
{
  struct stat filestat;
  int ret;
  char *rdir;

  rdir = GNUNET_STRINGS_filename_expand (fil);
  if (rdir == NULL)
    return GNUNET_SYSERR;

  ret = STAT (rdir, &filestat);
  if (ret != 0)
  {
    if (errno != ENOENT)
    {
      LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "stat", rdir);
      GNUNET_free (rdir);
      return GNUNET_SYSERR;
    }
    GNUNET_free (rdir);
    return GNUNET_NO;
  }
  if (!S_ISREG (filestat.st_mode))
  {
    GNUNET_free (rdir);
    return GNUNET_NO;
  }
  if (ACCESS (rdir, F_OK) < 0)
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "access", rdir);
    GNUNET_free (rdir);
    return GNUNET_SYSERR;
  }
  GNUNET_free (rdir);
  return GNUNET_YES;
}


/**
 * Implementation of "mkdir -p"
 *
 * @param dir the directory to create
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
 */
int
GNUNET_DISK_directory_create (const char *dir)
{
  char *rdir;
  unsigned int len;
  unsigned int pos;
  unsigned int pos2;
  int ret = GNUNET_OK;

  rdir = GNUNET_STRINGS_filename_expand (dir);
  if (rdir == NULL)
    return GNUNET_SYSERR;

  len = strlen (rdir);
#ifndef MINGW
  pos = 1;                      /* skip heading '/' */
#else
  /* Local or Network path? */
  if (strncmp (rdir, "\\\\", 2) == 0)
  {
    pos = 2;
    while (rdir[pos])
    {
      if (rdir[pos] == '\\')
      {
        pos++;
        break;
      }
      pos++;
    }
  }
  else
  {
    pos = 3;                    /* strlen("C:\\") */
  }
#endif
  /* Check which low level directories already exist */
  pos2 = len;
  rdir[len] = DIR_SEPARATOR;
  while (pos <= pos2)
  {
    if (DIR_SEPARATOR == rdir[pos2])
    {
      rdir[pos2] = '\0';
      ret = GNUNET_DISK_directory_test (rdir, GNUNET_NO);
      if (GNUNET_NO == ret)
      {
        GNUNET_free (rdir);
        return GNUNET_SYSERR;
      }
      rdir[pos2] = DIR_SEPARATOR;
      if (GNUNET_YES == ret)
      {
        pos2++;
        break;
      }
    }
    pos2--;
  }
  rdir[len] = '\0';
  if (pos < pos2)
    pos = pos2;
  /* Start creating directories */
  while (pos <= len)
  {
    if ((rdir[pos] == DIR_SEPARATOR) || (pos == len))
    {
      rdir[pos] = '\0';
      ret = GNUNET_DISK_directory_test (rdir, GNUNET_NO);
      if (GNUNET_NO == ret)
      {
        GNUNET_free (rdir);
        return GNUNET_SYSERR;
      }
      if (GNUNET_SYSERR == ret)
      {
#ifndef MINGW
        ret = mkdir (rdir, S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);        /* 755 */
#else
        wchar_t wrdir[MAX_PATH + 1];
        if (ERROR_SUCCESS == plibc_conv_to_win_pathwconv(rdir, wrdir))
          ret = !CreateDirectoryW (wrdir, NULL);
        else
          ret = 1;
#endif
        if ((ret != 0) && (errno != EEXIST))
        {
          LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "mkdir", rdir);
          GNUNET_free (rdir);
          return GNUNET_SYSERR;
        }
      }
      rdir[pos] = DIR_SEPARATOR;
    }
    pos++;
  }
  GNUNET_free (rdir);
  return GNUNET_OK;
}


/**
 * Create the directory structure for storing a file.
 *
 * @param filename name of a file in the directory
 * @returns #GNUNET_OK on success,
 *          #GNUNET_SYSERR on failure,
 *          #GNUNET_NO if the directory
 *          exists but is not writeable for us
 */
int
GNUNET_DISK_directory_create_for_file (const char *filename)
{
  char *rdir;
  size_t len;
  int ret;
  int eno;

  rdir = GNUNET_STRINGS_filename_expand (filename);
  if (NULL == rdir)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }
  len = strlen (rdir);
  while ((len > 0) && (rdir[len] != DIR_SEPARATOR))
    len--;
  rdir[len] = '\0';
  /* The empty path is invalid and in this case refers to / */
  if (0 == len)
  {
    GNUNET_free (rdir);
    rdir = GNUNET_strdup ("/");
  }
  ret = GNUNET_DISK_directory_create (rdir);
  if ((GNUNET_OK == ret) && (0 != ACCESS (rdir, W_OK)))
    ret = GNUNET_NO;
  eno = errno;
  GNUNET_free (rdir);
  errno = eno;
  return ret;
}


/**
 * Read the contents of a binary file into a buffer.
 *
 * @param h handle to an open file
 * @param result the buffer to write the result to
 * @param len the maximum number of bytes to read
 * @return the number of bytes read on success, #GNUNET_SYSERR on failure
 */
ssize_t
GNUNET_DISK_file_read (const struct GNUNET_DISK_FileHandle *h,
                       void *result,
                       size_t len)
{
  if (NULL == h)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifdef MINGW
  DWORD bytes_read;

  if (h->type == GNUNET_DISK_HANLDE_TYPE_FILE)
  {
    if (!ReadFile (h->h, result, len, &bytes_read, NULL))
    {
      SetErrnoFromWinError (GetLastError ());
      return GNUNET_SYSERR;
    }
  }
  else if (h->type == GNUNET_DISK_HANLDE_TYPE_PIPE)
  {
    if (!ReadFile (h->h, result, len, &bytes_read, h->oOverlapRead))
    {
      if (GetLastError () != ERROR_IO_PENDING)
      {
        LOG (GNUNET_ERROR_TYPE_DEBUG,
             "Error reading from pipe: %u\n",
             GetLastError ());
        SetErrnoFromWinError (GetLastError ());
        return GNUNET_SYSERR;
      }
      LOG (GNUNET_ERROR_TYPE_DEBUG, "Will get overlapped result\n");
      GetOverlappedResult (h->h, h->oOverlapRead, &bytes_read, TRUE);
    }
    LOG (GNUNET_ERROR_TYPE_DEBUG, "Read %u bytes from pipe\n", bytes_read);
  }
  else
  {
    bytes_read = 0;
  }
  return bytes_read;
#else
  return read (h->fd, result, len);
#endif
}


/**
 * Read the contents of a binary file into a buffer.
 * Guarantees not to block (returns GNUNET_SYSERR and sets errno to EAGAIN
 * when no data can be read).
 *
 * @param h handle to an open file
 * @param result the buffer to write the result to
 * @param len the maximum number of bytes to read
 * @return the number of bytes read on success, #GNUNET_SYSERR on failure
 */
ssize_t
GNUNET_DISK_file_read_non_blocking (const struct GNUNET_DISK_FileHandle *h,
				    void *result,
				    size_t len)
{
  if (NULL == h)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifdef MINGW
  DWORD bytes_read;

  if (h->type == GNUNET_DISK_HANLDE_TYPE_FILE)
  {
    if (!ReadFile (h->h, result, len, &bytes_read, NULL))
    {
      SetErrnoFromWinError (GetLastError ());
      return GNUNET_SYSERR;
    }
  }
  else if (h->type == GNUNET_DISK_HANLDE_TYPE_PIPE)
  {
    if (!ReadFile (h->h, result, len, &bytes_read, h->oOverlapRead))
    {
      if (GetLastError () != ERROR_IO_PENDING)
      {
        LOG (GNUNET_ERROR_TYPE_DEBUG, "Error reading from pipe: %u\n", GetLastError ());
        SetErrnoFromWinError (GetLastError ());
        return GNUNET_SYSERR;
      }
      else
      {
        LOG (GNUNET_ERROR_TYPE_DEBUG,
            "ReadFile() queued a read, cancelling\n");
        CancelIo (h->h);
        errno = EAGAIN;
        return GNUNET_SYSERR;
      }
    }
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Read %u bytes\n",
         bytes_read);
  }
  else
  {
    bytes_read = 0;
  }
  return bytes_read;
#else
  int flags;
  ssize_t ret;

  /* set to non-blocking, read, then set back */
  flags = fcntl (h->fd, F_GETFL);
  if (0 == (flags & O_NONBLOCK))
    (void) fcntl (h->fd, F_SETFL, flags | O_NONBLOCK);
  ret = read (h->fd, result, len);
  if (0 == (flags & O_NONBLOCK))
    {
      int eno = errno;
      (void) fcntl (h->fd, F_SETFL, flags);
      errno = eno;
    }
  return ret;
#endif
}


/**
 * Read the contents of a binary file into a buffer.
 *
 * @param fn file name
 * @param result the buffer to write the result to
 * @param len the maximum number of bytes to read
 * @return number of bytes read, #GNUNET_SYSERR on failure
 */
ssize_t
GNUNET_DISK_fn_read (const char *fn,
                     void *result,
                     size_t len)
{
  struct GNUNET_DISK_FileHandle *fh;
  ssize_t ret;
  int eno;

  fh = GNUNET_DISK_file_open (fn,
                              GNUNET_DISK_OPEN_READ,
                              GNUNET_DISK_PERM_NONE);
  if (NULL == fh)
    return GNUNET_SYSERR;
  ret = GNUNET_DISK_file_read (fh, result, len);
  eno = errno;
  GNUNET_assert (GNUNET_OK == GNUNET_DISK_file_close (fh));
  errno = eno;
  return ret;
}


/**
 * Write a buffer to a file.
 *
 * @param h handle to open file
 * @param buffer the data to write
 * @param n number of bytes to write
 * @return number of bytes written on success, #GNUNET_SYSERR on error
 */
ssize_t
GNUNET_DISK_file_write (const struct GNUNET_DISK_FileHandle * h,
                        const void *buffer, size_t n)
{
  if (NULL == h)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifdef MINGW
  DWORD bytes_written;

  if (h->type == GNUNET_DISK_HANLDE_TYPE_FILE)
  {
    if (!WriteFile (h->h, buffer, n, &bytes_written, NULL))
    {
      SetErrnoFromWinError (GetLastError ());
      return GNUNET_SYSERR;
    }
  }
  else if (h->type == GNUNET_DISK_HANLDE_TYPE_PIPE)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG, "It is a pipe trying to write %u bytes\n", n);
    if (!WriteFile (h->h, buffer, n, &bytes_written, h->oOverlapWrite))
    {
      if (GetLastError () != ERROR_IO_PENDING)
      {
        SetErrnoFromWinError (GetLastError ());
        LOG (GNUNET_ERROR_TYPE_DEBUG, "Error writing to pipe: %u\n",
            GetLastError ());
        return GNUNET_SYSERR;
      }
      LOG (GNUNET_ERROR_TYPE_DEBUG, "Will get overlapped result\n");
      if (!GetOverlappedResult (h->h, h->oOverlapWrite, &bytes_written, TRUE))
      {
        SetErrnoFromWinError (GetLastError ());
        LOG (GNUNET_ERROR_TYPE_DEBUG,
            "Error getting overlapped result while writing to pipe: %u\n",
            GetLastError ());
        return GNUNET_SYSERR;
      }
    }
    else
    {
      DWORD ovr;
      if (!GetOverlappedResult (h->h, h->oOverlapWrite, &ovr, TRUE))
      {
        LOG (GNUNET_ERROR_TYPE_DEBUG,
            "Error getting control overlapped result while writing to pipe: %u\n",
            GetLastError ());
      }
      else
      {
        LOG (GNUNET_ERROR_TYPE_DEBUG,
            "Wrote %u bytes (ovr says %u), picking the greatest\n",
            bytes_written, ovr);
      }
    }
    if (bytes_written == 0)
    {
      if (n > 0)
      {
        LOG (GNUNET_ERROR_TYPE_DEBUG, "Wrote %u bytes, returning -1 with EAGAIN\n", bytes_written);
        errno = EAGAIN;
        return GNUNET_SYSERR;
      }
    }
    LOG (GNUNET_ERROR_TYPE_DEBUG, "Wrote %u bytes\n", bytes_written);
  }
  else
  {
    bytes_written = 0;
  }
  return bytes_written;
#else
  return write (h->fd, buffer, n);
#endif
}


/**
 * Write a buffer to a file, blocking, if necessary.
 *
 * @param h handle to open file
 * @param buffer the data to write
 * @param n number of bytes to write
 * @return number of bytes written on success, #GNUNET_SYSERR on error
 */
ssize_t
GNUNET_DISK_file_write_blocking (const struct GNUNET_DISK_FileHandle * h,
                                 const void *buffer,
                                 size_t n)
{
  if (NULL == h)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifdef MINGW
  DWORD bytes_written;
  /* We do a non-overlapped write, which is as blocking as it gets */
  LOG (GNUNET_ERROR_TYPE_DEBUG, "Writing %u bytes\n", n);
  if (!WriteFile (h->h, buffer, n, &bytes_written, NULL))
  {
    SetErrnoFromWinError (GetLastError ());
    LOG (GNUNET_ERROR_TYPE_DEBUG, "Error writing to pipe: %u\n",
        GetLastError ());
    return GNUNET_SYSERR;
  }
  if (bytes_written == 0 && n > 0)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG, "Waiting for pipe to clean\n");
    WaitForSingleObject (h->h, INFINITE);
    if (!WriteFile (h->h, buffer, n, &bytes_written, NULL))
    {
      SetErrnoFromWinError (GetLastError ());
      LOG (GNUNET_ERROR_TYPE_DEBUG, "Error writing to pipe: %u\n",
          GetLastError ());
      return GNUNET_SYSERR;
    }
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Wrote %u bytes\n",
       bytes_written);
  return bytes_written;
#else
  int flags;
  ssize_t ret;

  /* set to blocking, write, then set back */
  flags = fcntl (h->fd, F_GETFL);
  if (0 != (flags & O_NONBLOCK))
    (void) fcntl (h->fd, F_SETFL, flags - O_NONBLOCK);
  ret = write (h->fd, buffer, n);
  if (0 == (flags & O_NONBLOCK))
    (void) fcntl (h->fd, F_SETFL, flags);
  return ret;
#endif
}


/**
 * Write a buffer to a file.  If the file is longer than the
 * number of bytes that will be written, it will be truncated.
 *
 * @param fn file name
 * @param buffer the data to write
 * @param n number of bytes to write
 * @param mode file permissions
 * @return number of bytes written on success, #GNUNET_SYSERR on error
 */
ssize_t
GNUNET_DISK_fn_write (const char *fn,
                      const void *buffer,
                      size_t n,
                      enum GNUNET_DISK_AccessPermissions mode)
{
  struct GNUNET_DISK_FileHandle *fh;
  ssize_t ret;

  fh = GNUNET_DISK_file_open (fn,
                              GNUNET_DISK_OPEN_WRITE | GNUNET_DISK_OPEN_TRUNCATE
                              | GNUNET_DISK_OPEN_CREATE, mode);
  if (! fh)
    return GNUNET_SYSERR;
  ret = GNUNET_DISK_file_write (fh, buffer, n);
  GNUNET_assert (GNUNET_OK == GNUNET_DISK_file_close (fh));
  return ret;
}


/**
 * Scan a directory for files.
 *
 * @param dir_name the name of the directory
 * @param callback the method to call for each file,
 *        can be NULL, in that case, we only count
 * @param callback_cls closure for @a callback
 * @return the number of files found, #GNUNET_SYSERR on error or
 *         ieration aborted by callback returning #GNUNET_SYSERR
 */
int
GNUNET_DISK_directory_scan (const char *dir_name,
                            GNUNET_FileNameCallback callback,
                            void *callback_cls)
{
  DIR *dinfo;
  struct dirent *finfo;
  struct stat istat;
  int count = 0;
  int ret;
  char *name;
  char *dname;
  unsigned int name_len;
  unsigned int n_size;

  GNUNET_assert (NULL != dir_name);
  dname = GNUNET_STRINGS_filename_expand (dir_name);
  if (NULL == dname)
    return GNUNET_SYSERR;
  while ( (strlen (dname) > 0) &&
          (dname[strlen (dname) - 1] == DIR_SEPARATOR) )
    dname[strlen (dname) - 1] = '\0';
  if (0 != STAT (dname, &istat))
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING,
                       "stat",
                       dname);
    GNUNET_free (dname);
    return GNUNET_SYSERR;
  }
  if (! S_ISDIR (istat.st_mode))
  {
    LOG (GNUNET_ERROR_TYPE_WARNING,
         _("Expected `%s' to be a directory!\n"),
         dir_name);
    GNUNET_free (dname);
    return GNUNET_SYSERR;
  }
  errno = 0;
  dinfo = OPENDIR (dname);
  if ( (EACCES == errno) ||
       (NULL == dinfo) )
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING,
                       "opendir",
                       dname);
    if (NULL != dinfo)
      CLOSEDIR (dinfo);
    GNUNET_free (dname);
    return GNUNET_SYSERR;
  }
  name_len = 256;
  n_size = strlen (dname) + name_len + strlen (DIR_SEPARATOR_STR) + 1;
  name = GNUNET_malloc (n_size);
  while (NULL != (finfo = READDIR (dinfo)))
  {
    if ( (0 == strcmp (finfo->d_name, ".")) ||
         (0 == strcmp (finfo->d_name, "..")) )
      continue;
    if (NULL != callback)
    {
      if (name_len < strlen (finfo->d_name))
      {
        GNUNET_free (name);
        name_len = strlen (finfo->d_name);
        n_size = strlen (dname) + name_len + strlen (DIR_SEPARATOR_STR) + 1;
        name = GNUNET_malloc (n_size);
      }
      /* dname can end in "/" only if dname == "/";
       * if dname does not end in "/", we need to add
       * a "/" (otherwise, we must not!) */
      GNUNET_snprintf (name,
                       n_size,
                       "%s%s%s",
                       dname,
                       (0 == strcmp (dname,
                                     DIR_SEPARATOR_STR))
                       ? ""
                       : DIR_SEPARATOR_STR,
                       finfo->d_name);
      ret = callback (callback_cls,
                      name);
      if (GNUNET_OK != ret)
      {
        CLOSEDIR (dinfo);
        GNUNET_free (name);
        GNUNET_free (dname);
        if (GNUNET_NO == ret)
          return count;
        return GNUNET_SYSERR;
      }
    }
    count++;
  }
  CLOSEDIR (dinfo);
  GNUNET_free (name);
  GNUNET_free (dname);
  return count;
}


/**
 * Function that removes the given directory by calling
 * #GNUNET_DISK_directory_remove().
 *
 * @param unused not used
 * @param fn directory to remove
 * @return #GNUNET_OK
 */
static int
remove_helper (void *unused,
               const char *fn)
{
  (void) unused;
  (void) GNUNET_DISK_directory_remove (fn);
  return GNUNET_OK;
}


/**
 * Remove all files in a directory (rm -r). Call with
 * caution.
 *
 * @param filename the file to remove
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
 */
int
GNUNET_DISK_directory_remove (const char *filename)
{
  struct stat istat;

  if (NULL == filename)
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  if (0 != LSTAT (filename, &istat))
    return GNUNET_NO;           /* file may not exist... */
  (void) CHMOD (filename,
                S_IWUSR | S_IRUSR | S_IXUSR);
  if (0 == UNLINK (filename))
    return GNUNET_OK;
  if ( (errno != EISDIR) &&
       /* EISDIR is not sufficient in all cases, e.g.
        * sticky /tmp directory may result in EPERM on BSD.
        * So we also explicitly check "isDirectory" */
       (GNUNET_YES !=
        GNUNET_DISK_directory_test (filename,
                                    GNUNET_YES)) )
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING,
                       "rmdir",
                       filename);
    return GNUNET_SYSERR;
  }
  if (GNUNET_SYSERR ==
      GNUNET_DISK_directory_scan (filename,
                                  &remove_helper,
                                  NULL))
    return GNUNET_SYSERR;
  if (0 != RMDIR (filename))
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING,
                       "rmdir",
                       filename);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}


/**
 * Copy a file.
 *
 * @param src file to copy
 * @param dst destination file name
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
 */
int
GNUNET_DISK_file_copy (const char *src,
                       const char *dst)
{
  char *buf;
  uint64_t pos;
  uint64_t size;
  size_t len;
  ssize_t sret;
  struct GNUNET_DISK_FileHandle *in;
  struct GNUNET_DISK_FileHandle *out;

  if (GNUNET_OK != GNUNET_DISK_file_size (src, &size, GNUNET_YES, GNUNET_YES))
    return GNUNET_SYSERR;
  pos = 0;
  in = GNUNET_DISK_file_open (src, GNUNET_DISK_OPEN_READ,
                              GNUNET_DISK_PERM_NONE);
  if (!in)
    return GNUNET_SYSERR;
  out =
      GNUNET_DISK_file_open (dst,
                             GNUNET_DISK_OPEN_WRITE | GNUNET_DISK_OPEN_CREATE |
                             GNUNET_DISK_OPEN_FAILIFEXISTS,
                             GNUNET_DISK_PERM_USER_READ |
                             GNUNET_DISK_PERM_USER_WRITE |
                             GNUNET_DISK_PERM_GROUP_READ |
                             GNUNET_DISK_PERM_GROUP_WRITE);
  if (!out)
  {
    GNUNET_DISK_file_close (in);
    return GNUNET_SYSERR;
  }
  buf = GNUNET_malloc (COPY_BLK_SIZE);
  while (pos < size)
  {
    len = COPY_BLK_SIZE;
    if (len > size - pos)
      len = size - pos;
    sret = GNUNET_DISK_file_read (in,
				  buf,
				  len);
    if ( (sret < 0) ||
	 (len != (size_t) sret) )
      goto FAIL;
    sret = GNUNET_DISK_file_write (out,
				   buf,
				   len);
    if ( (sret < 0) ||
	 (len != (size_t) sret) )
      goto FAIL;
    pos += len;
  }
  GNUNET_free (buf);
  GNUNET_DISK_file_close (in);
  GNUNET_DISK_file_close (out);
  return GNUNET_OK;
FAIL:
  GNUNET_free (buf);
  GNUNET_DISK_file_close (in);
  GNUNET_DISK_file_close (out);
  return GNUNET_SYSERR;
}


/**
 * @brief Removes special characters as ':' from a filename.
 * @param fn the filename to canonicalize
 */
void
GNUNET_DISK_filename_canonicalize (char *fn)
{
  char *idx;
  char c;

  for (idx = fn; *idx; idx++)
  {
    c = *idx;

    if (c == '/' || c == '\\' || c == ':' ||
	c == '*' || c == '?' || c == '"' ||
        c == '<' || c == '>' || c == '|')
    {
      *idx = '_';
    }
  }
}



/**
 * @brief Change owner of a file
 *
 * @param filename name of file to change the owner of
 * @param user name of the new owner
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
 */
int
GNUNET_DISK_file_change_owner (const char *filename,
                               const char *user)
{
#ifndef MINGW
  struct passwd *pws;

  pws = getpwnam (user);
  if (NULL == pws)
  {
    LOG (GNUNET_ERROR_TYPE_ERROR,
         _("Cannot obtain information about user `%s': %s\n"),
         user,
         STRERROR (errno));
    return GNUNET_SYSERR;
  }
  if (0 != chown (filename,
                  pws->pw_uid,
                  pws->pw_gid))
  {
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING,
                       "chown",
                       filename);
    return GNUNET_SYSERR;
  }
#endif
  return GNUNET_OK;
}


/**
 * Lock a part of a file
 *
 * @param fh file handle
 * @param lock_start absolute position from where to lock
 * @param lock_end absolute position until where to lock
 * @param excl #GNUNET_YES for an exclusive lock
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
 */
int
GNUNET_DISK_file_lock (struct GNUNET_DISK_FileHandle *fh,
                       off_t lock_start,
                       off_t lock_end,
                       int excl)
{
  if (fh == NULL)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifndef MINGW
  struct flock fl;

  memset (&fl, 0, sizeof (struct flock));
  fl.l_type = excl ? F_WRLCK : F_RDLCK;
  fl.l_whence = SEEK_SET;
  fl.l_start = lock_start;
  fl.l_len = lock_end;

  return fcntl (fh->fd, F_SETLK, &fl) != 0 ? GNUNET_SYSERR : GNUNET_OK;
#else
  OVERLAPPED o;
  off_t diff = lock_end - lock_start;
  DWORD diff_low, diff_high;
  diff_low = (DWORD) (diff & 0xFFFFFFFF);
  diff_high = (DWORD) ((diff >> (sizeof (DWORD) * 8)) & 0xFFFFFFFF);

  memset (&o, 0, sizeof (OVERLAPPED));
  o.Offset = (DWORD) (lock_start & 0xFFFFFFFF);;
  o.OffsetHigh = (DWORD) (((lock_start & ~0xFFFFFFFF) >> (sizeof (DWORD) * 8)) & 0xFFFFFFFF);

  if (!LockFileEx
      (fh->h, (excl ? LOCKFILE_EXCLUSIVE_LOCK : 0) | LOCKFILE_FAIL_IMMEDIATELY,
       0, diff_low, diff_high, &o))
  {
    SetErrnoFromWinError (GetLastError ());
    return GNUNET_SYSERR;
  }

  return GNUNET_OK;
#endif
}


/**
 * Unlock a part of a file
 *
 * @param fh file handle
 * @param unlock_start absolute position from where to unlock
 * @param unlock_end absolute position until where to unlock
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
 */
int
GNUNET_DISK_file_unlock (struct GNUNET_DISK_FileHandle *fh,
                         off_t unlock_start,
                         off_t unlock_end)
{
  if (fh == NULL)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifndef MINGW
  struct flock fl;

  memset (&fl, 0, sizeof (struct flock));
  fl.l_type = F_UNLCK;
  fl.l_whence = SEEK_SET;
  fl.l_start = unlock_start;
  fl.l_len = unlock_end;

  return fcntl (fh->fd, F_SETLK, &fl) != 0 ? GNUNET_SYSERR : GNUNET_OK;
#else
  OVERLAPPED o;
  off_t diff = unlock_end - unlock_start;
  DWORD diff_low, diff_high;
  diff_low = (DWORD) (diff & 0xFFFFFFFF);
  diff_high = (DWORD) ((diff >> (sizeof (DWORD) * 8)) & 0xFFFFFFFF);

  memset (&o, 0, sizeof (OVERLAPPED));
  o.Offset = (DWORD) (unlock_start & 0xFFFFFFFF);;
  o.OffsetHigh = (DWORD) (((unlock_start & ~0xFFFFFFFF) >> (sizeof (DWORD) * 8)) & 0xFFFFFFFF);

  if (!UnlockFileEx (fh->h, 0, diff_low, diff_high, &o))
  {
    SetErrnoFromWinError (GetLastError ());
    return GNUNET_SYSERR;
  }

  return GNUNET_OK;
#endif
}


/**
 * Open a file.  Note that the access permissions will only be
 * used if a new file is created and if the underlying operating
 * system supports the given permissions.
 *
 * @param fn file name to be opened
 * @param flags opening flags, a combination of GNUNET_DISK_OPEN_xxx bit flags
 * @param perm permissions for the newly created file, use
 *             #GNUNET_DISK_PERM_NONE if a file could not be created by this
 *             call (because of flags)
 * @return IO handle on success, NULL on error
 */
struct GNUNET_DISK_FileHandle *
GNUNET_DISK_file_open (const char *fn,
                       enum GNUNET_DISK_OpenFlags flags,
                       enum GNUNET_DISK_AccessPermissions perm)
{
  char *expfn;
  struct GNUNET_DISK_FileHandle *ret;

#ifdef MINGW
  DWORD access;
  DWORD disp;
  HANDLE h;
  wchar_t wexpfn[MAX_PATH + 1];
#else
  int oflags;
  int mode;
  int fd;
#endif

  expfn = GNUNET_STRINGS_filename_expand (fn);
  if (NULL == expfn)
    return NULL;
#ifndef MINGW
  mode = 0;
  if (GNUNET_DISK_OPEN_READWRITE == (flags & GNUNET_DISK_OPEN_READWRITE))
    oflags = O_RDWR;            /* note: O_RDWR is NOT always O_RDONLY | O_WRONLY */
  else if (flags & GNUNET_DISK_OPEN_READ)
    oflags = O_RDONLY;
  else if (flags & GNUNET_DISK_OPEN_WRITE)
    oflags = O_WRONLY;
  else
  {
    GNUNET_break (0);
    GNUNET_free (expfn);
    return NULL;
  }
  if (flags & GNUNET_DISK_OPEN_FAILIFEXISTS)
    oflags |= (O_CREAT | O_EXCL);
  if (flags & GNUNET_DISK_OPEN_TRUNCATE)
    oflags |= O_TRUNC;
  if (flags & GNUNET_DISK_OPEN_APPEND)
    oflags |= O_APPEND;
  if (flags & GNUNET_DISK_OPEN_CREATE)
  {
    (void) GNUNET_DISK_directory_create_for_file (expfn);
    oflags |= O_CREAT;
    mode = translate_unix_perms (perm);
  }

  fd = open (expfn, oflags
#if O_CLOEXEC
	     | O_CLOEXEC
#endif
	     | O_LARGEFILE, mode);
  if (fd == -1)
  {
    if (0 == (flags & GNUNET_DISK_OPEN_FAILIFEXISTS))
      LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "open", expfn);
    else
      LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_DEBUG, "open", expfn);
    GNUNET_free (expfn);
    return NULL;
  }
#else
  access = 0;
  disp = OPEN_ALWAYS;

  if (GNUNET_DISK_OPEN_READWRITE == (flags & GNUNET_DISK_OPEN_READWRITE))
    access = FILE_READ_DATA | FILE_WRITE_DATA;
  else if (flags & GNUNET_DISK_OPEN_READ)
    access = FILE_READ_DATA;
  else if (flags & GNUNET_DISK_OPEN_WRITE)
    access = FILE_WRITE_DATA;

  if (flags & GNUNET_DISK_OPEN_FAILIFEXISTS)
  {
    disp = CREATE_NEW;
  }
  else if (flags & GNUNET_DISK_OPEN_CREATE)
  {
    (void) GNUNET_DISK_directory_create_for_file (expfn);
    if (flags & GNUNET_DISK_OPEN_TRUNCATE)
      disp = CREATE_ALWAYS;
    else
      disp = OPEN_ALWAYS;
  }
  else if (flags & GNUNET_DISK_OPEN_TRUNCATE)
  {
    disp = TRUNCATE_EXISTING;
  }
  else
  {
    disp = OPEN_EXISTING;
  }

  if (ERROR_SUCCESS == plibc_conv_to_win_pathwconv(expfn, wexpfn))
    h = CreateFileW (wexpfn, access,
                    FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
                    disp, FILE_ATTRIBUTE_NORMAL, NULL);
  else
    h = INVALID_HANDLE_VALUE;
  if (h == INVALID_HANDLE_VALUE)
  {
    int err;
    SetErrnoFromWinError (GetLastError ());
    err = errno;
    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_INFO, "open", expfn);
    GNUNET_free (expfn);
    errno = err;
    return NULL;
  }

  if (flags & GNUNET_DISK_OPEN_APPEND)
    if (SetFilePointer (h, 0, 0, FILE_END) == INVALID_SET_FILE_POINTER)
    {
      SetErrnoFromWinError (GetLastError ());
      LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "SetFilePointer", expfn);
      CloseHandle (h);
      GNUNET_free (expfn);
      return NULL;
    }
#endif

  ret = GNUNET_new (struct GNUNET_DISK_FileHandle);
#ifdef MINGW
  ret->h = h;
  ret->type = GNUNET_DISK_HANLDE_TYPE_FILE;
#else
  ret->fd = fd;
#endif
  GNUNET_free (expfn);
  return ret;
}


/**
 * Close an open file.
 *
 * @param h file handle
 * @return #GNUNET_OK on success, #GNUNET_SYSERR otherwise
 */
int
GNUNET_DISK_file_close (struct GNUNET_DISK_FileHandle *h)
{
  int ret;
  if (h == NULL)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

  ret = GNUNET_OK;

#if MINGW
  if (! CloseHandle (h->h))
  {
    SetErrnoFromWinError (GetLastError ());
    LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "close");
    ret = GNUNET_SYSERR;
  }
  if (h->oOverlapRead)
  {
    if (! CloseHandle (h->oOverlapRead->hEvent))
    {
      SetErrnoFromWinError (GetLastError ());
      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "close");
      ret = GNUNET_SYSERR;
    }
    GNUNET_free (h->oOverlapRead);
  }
  if (h->oOverlapWrite)
  {
    if (!CloseHandle (h->oOverlapWrite->hEvent))
    {
      SetErrnoFromWinError (GetLastError ());
      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "close");
      ret = GNUNET_SYSERR;
    }
    GNUNET_free (h->oOverlapWrite);
  }
#else
  if (close (h->fd) != 0)
  {
    LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "close");
    ret = GNUNET_SYSERR;
  }
#endif
  GNUNET_free (h);
  return ret;
}


#ifdef WINDOWS
/**
 * Get a GNUnet file handle from a W32 handle.
 *
 * @param handle native handle
 * @return GNUnet file handle corresponding to the W32 handle
 */
struct GNUNET_DISK_FileHandle *
GNUNET_DISK_get_handle_from_w32_handle (HANDLE osfh)
{
  struct GNUNET_DISK_FileHandle *fh;
  DWORD dwret;
  enum GNUNET_FILE_Type ftype;

  dwret = GetFileType (osfh);
  switch (dwret)
  {
  case FILE_TYPE_DISK:
    ftype = GNUNET_DISK_HANLDE_TYPE_FILE;
    break;
  case FILE_TYPE_PIPE:
    ftype = GNUNET_DISK_HANLDE_TYPE_PIPE;
    break;
  case FILE_TYPE_UNKNOWN:
    if ( (GetLastError () == NO_ERROR) ||
         (GetLastError () == ERROR_INVALID_HANDLE) )
    {
      if (0 != ResetEvent (osfh))
        ftype = GNUNET_DISK_HANLDE_TYPE_EVENT;
      else
        return NULL;
    }
    else
      return NULL;
    break;
  default:
    return NULL;
  }

  fh = GNUNET_new (struct GNUNET_DISK_FileHandle);

  fh->h = osfh;
  fh->type = ftype;
  if (ftype == GNUNET_DISK_HANLDE_TYPE_PIPE)
  {
    /**
     * Note that we can't make it overlapped if it isn't already.
     * (ReOpenFile() is only available in 2003/Vista).
     * The process that opened this file in the first place (usually a parent
     * process, if this is stdin/stdout/stderr) must make it overlapped,
     * otherwise we're screwed, as selecting on non-overlapped handle
     * will block.
     */
    fh->oOverlapRead = GNUNET_new (OVERLAPPED);
    fh->oOverlapWrite = GNUNET_new (OVERLAPPED);
    fh->oOverlapRead->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
    fh->oOverlapWrite->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
  }

  return fh;
}
#endif

/**
 * Get a handle from a native integer FD.
 *
 * @param fno native integer file descriptor
 * @return file handle corresponding to the descriptor, NULL on error
 */
struct GNUNET_DISK_FileHandle *
GNUNET_DISK_get_handle_from_int_fd (int fno)
{
  struct GNUNET_DISK_FileHandle *fh;

  if ( (((off_t) -1) == lseek (fno, 0, SEEK_CUR)) &&
       (EBADF == errno) )
    return NULL; /* invalid FD */

#ifndef WINDOWS
  fh = GNUNET_new (struct GNUNET_DISK_FileHandle);

  fh->fd = fno;
#else
  intptr_t osfh;

  osfh = _get_osfhandle (fno);
  if (INVALID_HANDLE_VALUE == (HANDLE) osfh)
    return NULL;

  fh = GNUNET_DISK_get_handle_from_w32_handle ((HANDLE) osfh);
#endif

  return fh;
}


/**
 * Get a handle from a native streaming FD.
 *
 * @param fd native streaming file descriptor
 * @return file handle corresponding to the descriptor
 */
struct GNUNET_DISK_FileHandle *
GNUNET_DISK_get_handle_from_native (FILE *fd)
{
  int fno;

  fno = fileno (fd);
  if (-1 == fno)
    return NULL;

  return GNUNET_DISK_get_handle_from_int_fd (fno);
}


/**
 * Handle for a memory-mapping operation.
 */
struct GNUNET_DISK_MapHandle
{
  /**
   * Address where the map is in memory.
   */
  void *addr;

#ifdef MINGW
  /**
   * Underlying OS handle.
   */
  HANDLE h;
#else
  /**
   * Number of bytes mapped.
   */
  size_t len;
#endif
};


#ifndef MAP_FAILED
#define MAP_FAILED ((void *) -1)
#endif

/**
 * Map a file into memory
 *
 * @param h open file handle
 * @param m handle to the new mapping
 * @param access access specification, GNUNET_DISK_MAP_TYPE_xxx
 * @param len size of the mapping
 * @return pointer to the mapped memory region, NULL on failure
 */
void *
GNUNET_DISK_file_map (const struct GNUNET_DISK_FileHandle *h,
                      struct GNUNET_DISK_MapHandle **m,
                      enum GNUNET_DISK_MapType access, size_t len)
{
  if (h == NULL)
  {
    errno = EINVAL;
    return NULL;
  }

#ifdef MINGW
  DWORD mapAccess, protect;

  if ((access & GNUNET_DISK_MAP_TYPE_READ) &&
      (access & GNUNET_DISK_MAP_TYPE_WRITE))
  {
    protect = PAGE_READWRITE;
    mapAccess = FILE_MAP_ALL_ACCESS;
  }
  else if (access & GNUNET_DISK_MAP_TYPE_READ)
  {
    protect = PAGE_READONLY;
    mapAccess = FILE_MAP_READ;
  }
  else if (access & GNUNET_DISK_MAP_TYPE_WRITE)
  {
    protect = PAGE_READWRITE;
    mapAccess = FILE_MAP_WRITE;
  }
  else
  {
    GNUNET_break (0);
    return NULL;
  }

  *m = GNUNET_new (struct GNUNET_DISK_MapHandle);
  (*m)->h = CreateFileMapping (h->h, NULL, protect, 0, 0, NULL);
  if ((*m)->h == INVALID_HANDLE_VALUE)
  {
    SetErrnoFromWinError (GetLastError ());
    GNUNET_free (*m);
    return NULL;
  }

  (*m)->addr = MapViewOfFile ((*m)->h, mapAccess, 0, 0, len);
  if (!(*m)->addr)
  {
    SetErrnoFromWinError (GetLastError ());
    CloseHandle ((*m)->h);
    GNUNET_free (*m);
  }

  return (*m)->addr;
#else
  int prot;

  prot = 0;
  if (access & GNUNET_DISK_MAP_TYPE_READ)
    prot = PROT_READ;
  if (access & GNUNET_DISK_MAP_TYPE_WRITE)
    prot |= PROT_WRITE;
  *m = GNUNET_new (struct GNUNET_DISK_MapHandle);
  (*m)->addr = mmap (NULL, len, prot, MAP_SHARED, h->fd, 0);
  GNUNET_assert (NULL != (*m)->addr);
  if (MAP_FAILED == (*m)->addr)
  {
    GNUNET_free (*m);
    return NULL;
  }
  (*m)->len = len;
  return (*m)->addr;
#endif
}

/**
 * Unmap a file
 * @param h mapping handle
 * @return GNUNET_OK on success, GNUNET_SYSERR otherwise
 */
int
GNUNET_DISK_file_unmap (struct GNUNET_DISK_MapHandle *h)
{
  int ret;

  if (h == NULL)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifdef MINGW
  ret = UnmapViewOfFile (h->addr) ? GNUNET_OK : GNUNET_SYSERR;
  if (ret != GNUNET_OK)
    SetErrnoFromWinError (GetLastError ());
  if (!CloseHandle (h->h) && (ret == GNUNET_OK))
  {
    ret = GNUNET_SYSERR;
    SetErrnoFromWinError (GetLastError ());
  }
#else
  ret = munmap (h->addr, h->len) != -1 ? GNUNET_OK : GNUNET_SYSERR;
#endif
  GNUNET_free (h);
  return ret;
}


/**
 * Write file changes to disk
 * @param h handle to an open file
 * @return GNUNET_OK on success, GNUNET_SYSERR otherwise
 */
int
GNUNET_DISK_file_sync (const struct GNUNET_DISK_FileHandle *h)
{
  if (h == NULL)
  {
    errno = EINVAL;
    return GNUNET_SYSERR;
  }

#ifdef MINGW
  int ret;

  ret = FlushFileBuffers (h->h) ? GNUNET_OK : GNUNET_SYSERR;
  if (ret != GNUNET_OK)
    SetErrnoFromWinError (GetLastError ());
  return ret;
#elif defined(FREEBSD) || defined(OPENBSD) || defined(DARWIN)
  return fsync (h->fd) == -1 ? GNUNET_SYSERR : GNUNET_OK;
#else
  return fdatasync (h->fd) == -1 ? GNUNET_SYSERR : GNUNET_OK;
#endif
}


#if WINDOWS
#ifndef PIPE_BUF
#define PIPE_BUF        512
#endif
/* Copyright Bob Byrnes  <byrnes <at> curl.com>
   http://permalink.gmane.org/gmane.os.cygwin.patches/2121
*/
/* Create a pipe, and return handles to the read and write ends,
   just like CreatePipe, but ensure that the write end permits
   FILE_READ_ATTRIBUTES access, on later versions of win32 where
   this is supported.  This access is needed by NtQueryInformationFile,
   which is used to implement select and nonblocking writes.
   Note that the return value is either NO_ERROR or GetLastError,
   unlike CreatePipe, which returns a bool for success or failure.  */
static int
create_selectable_pipe (PHANDLE read_pipe_ptr, PHANDLE write_pipe_ptr,
                        LPSECURITY_ATTRIBUTES sa_ptr, DWORD psize,
                        DWORD dwReadMode, DWORD dwWriteMode)
{
  /* Default to error. */
  *read_pipe_ptr = *write_pipe_ptr = INVALID_HANDLE_VALUE;

  HANDLE read_pipe;
  HANDLE write_pipe;

  /* Ensure that there is enough pipe buffer space for atomic writes.  */
  if (psize < PIPE_BUF)
    psize = PIPE_BUF;

  char pipename[MAX_PATH];

  /* Retry CreateNamedPipe as long as the pipe name is in use.
   * Retrying will probably never be necessary, but we want
   * to be as robust as possible.  */
  while (1)
  {
    static volatile LONG pipe_unique_id;

    snprintf (pipename, sizeof pipename, "\\\\.\\pipe\\gnunet-%d-%ld",
              getpid (), InterlockedIncrement ((LONG *) & pipe_unique_id));
    LOG (GNUNET_ERROR_TYPE_DEBUG, "CreateNamedPipe: name = %s, size = %lu\n",
         pipename, psize);
    /* Use CreateNamedPipe instead of CreatePipe, because the latter
     * returns a write handle that does not permit FILE_READ_ATTRIBUTES
     * access, on versions of win32 earlier than WinXP SP2.
     * CreatePipe also stupidly creates a full duplex pipe, which is
     * a waste, since only a single direction is actually used.
     * It's important to only allow a single instance, to ensure that
     * the pipe was not created earlier by some other process, even if
     * the pid has been reused.  */
    read_pipe = CreateNamedPipeA (pipename, PIPE_ACCESS_INBOUND | FILE_FLAG_FIRST_PIPE_INSTANCE | dwReadMode, PIPE_TYPE_BYTE | PIPE_READMODE_BYTE, 1,   /* max instances */
                                  psize,        /* output buffer size */
                                  psize,        /* input buffer size */
                                  NMPWAIT_USE_DEFAULT_WAIT, sa_ptr);

    if (read_pipe != INVALID_HANDLE_VALUE)
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG, "pipe read handle = %p\n", read_pipe);
      break;
    }

    DWORD err = GetLastError ();

    switch (err)
    {
    case ERROR_PIPE_BUSY:
      /* The pipe is already open with compatible parameters.
       * Pick a new name and retry.  */
      LOG (GNUNET_ERROR_TYPE_DEBUG, "pipe busy, retrying\n");
      continue;
    case ERROR_ACCESS_DENIED:
      /* The pipe is already open with incompatible parameters.
       * Pick a new name and retry.  */
      LOG (GNUNET_ERROR_TYPE_DEBUG, "pipe access denied, retrying\n");
      continue;
    case ERROR_CALL_NOT_IMPLEMENTED:
      /* We are on an older Win9x platform without named pipes.
       * Return an anonymous pipe as the best approximation.  */
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "CreateNamedPipe not implemented, resorting to "
           "CreatePipe: size = %lu\n", psize);
      if (CreatePipe (read_pipe_ptr, write_pipe_ptr, sa_ptr, psize))
      {
        LOG (GNUNET_ERROR_TYPE_DEBUG, "pipe read handle = %p, write handle = %p\n",
             *read_pipe_ptr,
             *write_pipe_ptr);
        return GNUNET_OK;
      }
      err = GetLastError ();
      LOG (GNUNET_ERROR_TYPE_ERROR, "CreatePipe failed: %d\n", err);
      return err;
    default:
      LOG (GNUNET_ERROR_TYPE_ERROR, "CreateNamedPipe failed: %d\n", err);
      return err;
    }
    /* NOTREACHED */
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG, "CreateFile: name = %s\n", pipename);

  /* Open the named pipe for writing.
   * Be sure to permit FILE_READ_ATTRIBUTES access.  */
  write_pipe = CreateFileA (pipename, GENERIC_WRITE | FILE_READ_ATTRIBUTES, 0,  /* share mode */
                            sa_ptr, OPEN_EXISTING, dwWriteMode, /* flags and attributes */
                            0); /* handle to template file */

  if (write_pipe == INVALID_HANDLE_VALUE)
  {
    /* Failure. */
    DWORD err = GetLastError ();

    LOG (GNUNET_ERROR_TYPE_DEBUG, "CreateFile failed: %d\n", err);
    CloseHandle (read_pipe);
    return err;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG, "pipe write handle = %p\n", write_pipe);
  /* Success. */
  *read_pipe_ptr = read_pipe;
  *write_pipe_ptr = write_pipe;
  return GNUNET_OK;
}
#endif


/**
 * Creates an interprocess channel
 *
 * @param blocking_read creates an asynchronous pipe for reading if set to GNUNET_NO
 * @param blocking_write creates an asynchronous pipe for writing if set to GNUNET_NO
 * @param inherit_read inherit the parent processes stdin (only for windows)
 * @param inherit_write inherit the parent processes stdout (only for windows)
 * @return handle to the new pipe, NULL on error
 */
struct GNUNET_DISK_PipeHandle *
GNUNET_DISK_pipe (int blocking_read,
		  int blocking_write,
		  int inherit_read,
		  int inherit_write)
{
#ifndef MINGW
  int fd[2];
  int ret;
  int eno;

  (void) inherit_read;
  (void) inherit_write;
  ret = pipe (fd);
  if (ret == -1)
  {
    eno = errno;
    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR,
		  "pipe");
    errno = eno;
    return NULL;
  }
  return GNUNET_DISK_pipe_from_fd (blocking_read,
				   blocking_write,
				   fd);
#else
  struct GNUNET_DISK_PipeHandle *p;
  BOOL ret;
  HANDLE tmp_handle;
  int save_errno;

  p = GNUNET_new (struct GNUNET_DISK_PipeHandle);
  p->fd[0] = GNUNET_new (struct GNUNET_DISK_FileHandle);
  p->fd[1] = GNUNET_new (struct GNUNET_DISK_FileHandle);

  /* All pipes are overlapped. If you want them to block - just
   * call WriteFile() and ReadFile() with NULL overlapped pointer.
   * NOTE: calling with NULL overlapped pointer works only
   * for pipes, and doesn't seem to be a documented feature.
   * It will NOT work for files, because overlapped files need
   * to read offsets from the overlapped structure, regardless.
   * Pipes are not seekable, and need no offsets, which is
   * probably why it works for them.
   */
  ret =
      create_selectable_pipe (&p->fd[0]->h, &p->fd[1]->h, NULL, 0,
                              FILE_FLAG_OVERLAPPED,
                              FILE_FLAG_OVERLAPPED);
  if (!ret)
  {
    SetErrnoFromWinError (GetLastError ());
    save_errno = errno;
    GNUNET_free (p->fd[0]);
    GNUNET_free (p->fd[1]);
    GNUNET_free (p);
    errno = save_errno;
    return NULL;
  }
  if (!DuplicateHandle
      (GetCurrentProcess (), p->fd[0]->h, GetCurrentProcess (), &tmp_handle, 0,
       inherit_read == GNUNET_YES ? TRUE : FALSE, DUPLICATE_SAME_ACCESS))
  {
    SetErrnoFromWinError (GetLastError ());
    save_errno = errno;
    CloseHandle (p->fd[0]->h);
    CloseHandle (p->fd[1]->h);
    GNUNET_free (p->fd[0]);
    GNUNET_free (p->fd[1]);
    GNUNET_free (p);
    errno = save_errno;
    return NULL;
  }
  CloseHandle (p->fd[0]->h);
  p->fd[0]->h = tmp_handle;

  if (!DuplicateHandle
      (GetCurrentProcess (), p->fd[1]->h, GetCurrentProcess (), &tmp_handle, 0,
       inherit_write == GNUNET_YES ? TRUE : FALSE, DUPLICATE_SAME_ACCESS))
  {
    SetErrnoFromWinError (GetLastError ());
    save_errno = errno;
    CloseHandle (p->fd[0]->h);
    CloseHandle (p->fd[1]->h);
    GNUNET_free (p->fd[0]);
    GNUNET_free (p->fd[1]);
    GNUNET_free (p);
    errno = save_errno;
    return NULL;
  }
  CloseHandle (p->fd[1]->h);
  p->fd[1]->h = tmp_handle;

  p->fd[0]->type = GNUNET_DISK_HANLDE_TYPE_PIPE;
  p->fd[1]->type = GNUNET_DISK_HANLDE_TYPE_PIPE;

  p->fd[0]->oOverlapRead = GNUNET_new (OVERLAPPED);
  p->fd[0]->oOverlapWrite = GNUNET_new (OVERLAPPED);
  p->fd[1]->oOverlapRead = GNUNET_new (OVERLAPPED);
  p->fd[1]->oOverlapWrite = GNUNET_new (OVERLAPPED);

  p->fd[0]->oOverlapRead->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
  p->fd[0]->oOverlapWrite->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);

  p->fd[1]->oOverlapRead->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
  p->fd[1]->oOverlapWrite->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);

  return p;
#endif
}


/**
 * Creates a pipe object from a couple of file descriptors.
 * Useful for wrapping existing pipe FDs.
 *
 * @param blocking_read creates an asynchronous pipe for reading if set to GNUNET_NO
 * @param blocking_write creates an asynchronous pipe for writing if set to GNUNET_NO
 * @param fd an array of two fd values. One of them may be -1 for read-only or write-only pipes
 *
 * @return handle to the new pipe, NULL on error
 */
struct GNUNET_DISK_PipeHandle *
GNUNET_DISK_pipe_from_fd (int blocking_read, int blocking_write, int fd[2])
{
  struct GNUNET_DISK_PipeHandle *p;

  p = GNUNET_new (struct GNUNET_DISK_PipeHandle);

#ifndef MINGW
  int ret;
  int flags;
  int eno = 0; /* make gcc happy */

  ret = 0;
  if (fd[0] >= 0)
  {
    p->fd[0] = GNUNET_new (struct GNUNET_DISK_FileHandle);
    p->fd[0]->fd = fd[0];
    if (!blocking_read)
    {
      flags = fcntl (fd[0], F_GETFL);
      flags |= O_NONBLOCK;
      if (0 > fcntl (fd[0], F_SETFL, flags))
      {
	ret = -1;
	eno = errno;
      }
    }
    flags = fcntl (fd[0], F_GETFD);
    flags |= FD_CLOEXEC;
    if (0 > fcntl (fd[0], F_SETFD, flags))
    {
      ret = -1;
      eno = errno;
    }
  }

  if (fd[1] >= 0)
  {
    p->fd[1] = GNUNET_new (struct GNUNET_DISK_FileHandle);
    p->fd[1]->fd = fd[1];
    if (!blocking_write)
    {
      flags = fcntl (fd[1], F_GETFL);
      flags |= O_NONBLOCK;
      if (0 > fcntl (fd[1], F_SETFL, flags))
      {
	ret = -1;
	eno = errno;
      }
    }
    flags = fcntl (fd[1], F_GETFD);
    flags |= FD_CLOEXEC;
    if (0 > fcntl (fd[1], F_SETFD, flags))
    {
      ret = -1;
      eno = errno;
    }
  }
  if (ret == -1)
  {
    errno = eno;
    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "fcntl");
    if (p->fd[0]->fd >= 0)
      GNUNET_break (0 == close (p->fd[0]->fd));
    if (p->fd[1]->fd >= 0)
      GNUNET_break (0 == close (p->fd[1]->fd));
    GNUNET_free_non_null (p->fd[0]);
    GNUNET_free_non_null (p->fd[1]);
    GNUNET_free (p);
    errno = eno;
    return NULL;
  }
#else
  if (fd[0] >= 0)
  {
    p->fd[0] = GNUNET_new (struct GNUNET_DISK_FileHandle);
    p->fd[0]->h = (HANDLE) _get_osfhandle (fd[0]);
    if (p->fd[0]->h != INVALID_HANDLE_VALUE)
    {
      p->fd[0]->type = GNUNET_DISK_HANLDE_TYPE_PIPE;
      p->fd[0]->oOverlapRead = GNUNET_new (OVERLAPPED);
      p->fd[0]->oOverlapWrite = GNUNET_new (OVERLAPPED);
      p->fd[0]->oOverlapRead->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
      p->fd[0]->oOverlapWrite->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
    }
    else
    {
      GNUNET_free (p->fd[0]);
      p->fd[0] = NULL;
    }
  }
  if (fd[1] >= 0)
  {
    p->fd[1] = GNUNET_new (struct GNUNET_DISK_FileHandle);
    p->fd[1]->h = (HANDLE) _get_osfhandle (fd[1]);
    if (p->fd[1]->h != INVALID_HANDLE_VALUE)
    {
      p->fd[1]->type = GNUNET_DISK_HANLDE_TYPE_PIPE;
      p->fd[1]->oOverlapRead = GNUNET_new (OVERLAPPED);
      p->fd[1]->oOverlapWrite = GNUNET_new (OVERLAPPED);
      p->fd[1]->oOverlapRead->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
      p->fd[1]->oOverlapWrite->hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
    }
    else
    {
      GNUNET_free (p->fd[1]);
      p->fd[1] = NULL;
    }
  }

#endif
  return p;
}


/**
 * Closes an interprocess channel
 *
 * @param p pipe to close
 * @param end which end of the pipe to close
 * @return GNUNET_OK on success, GNUNET_SYSERR otherwise
 */
int
GNUNET_DISK_pipe_close_end (struct GNUNET_DISK_PipeHandle *p,
                            enum GNUNET_DISK_PipeEnd end)
{
  int ret = GNUNET_OK;

  if (end == GNUNET_DISK_PIPE_END_READ)
  {
    if (p->fd[0])
    {
      ret = GNUNET_DISK_file_close (p->fd[0]);
      p->fd[0] = NULL;
    }
  }
  else if (end == GNUNET_DISK_PIPE_END_WRITE)
  {
    if (p->fd[1])
    {
      ret = GNUNET_DISK_file_close (p->fd[1]);
      p->fd[1] = NULL;
    }
  }

  return ret;
}

/**
 * Detaches one of the ends from the pipe.
 * Detached end is a fully-functional FileHandle, it will
 * not be affected by anything you do with the pipe afterwards.
 * Each end of a pipe can only be detched from it once (i.e.
 * it is not duplicated).
 *
 * @param p pipe to detach an end from
 * @param end which end of the pipe to detach
 * @return Detached end on success, NULL on failure
 * (or if that end is not present or is closed).
 */
struct GNUNET_DISK_FileHandle *
GNUNET_DISK_pipe_detach_end (struct GNUNET_DISK_PipeHandle *p,
                             enum GNUNET_DISK_PipeEnd end)
{
  struct GNUNET_DISK_FileHandle *ret = NULL;

  if (end == GNUNET_DISK_PIPE_END_READ)
  {
    if (p->fd[0])
    {
      ret = p->fd[0];
      p->fd[0] = NULL;
    }
  }
  else if (end == GNUNET_DISK_PIPE_END_WRITE)
  {
    if (p->fd[1])
    {
      ret = p->fd[1];
      p->fd[1] = NULL;
    }
  }

  return ret;
}


/**
 * Closes an interprocess channel
 *
 * @param p pipe to close
 * @return GNUNET_OK on success, GNUNET_SYSERR otherwise
 */
int
GNUNET_DISK_pipe_close (struct GNUNET_DISK_PipeHandle *p)
{
  int ret = GNUNET_OK;

  int read_end_close;
  int write_end_close;
  int read_end_close_errno;
  int write_end_close_errno;

  read_end_close = GNUNET_DISK_pipe_close_end (p, GNUNET_DISK_PIPE_END_READ);
  read_end_close_errno = errno;
  write_end_close = GNUNET_DISK_pipe_close_end (p, GNUNET_DISK_PIPE_END_WRITE);
  write_end_close_errno = errno;
  GNUNET_free (p);

  if (GNUNET_OK != read_end_close)
  {
    errno = read_end_close_errno;
    ret = read_end_close;
  }
  else if (GNUNET_OK != write_end_close)
  {
    errno = write_end_close_errno;
    ret = write_end_close;
  }

  return ret;
}


/**
 * Get the handle to a particular pipe end
 *
 * @param p pipe
 * @param n end to access
 * @return handle for the respective end
 */
const struct GNUNET_DISK_FileHandle *
GNUNET_DISK_pipe_handle (const struct GNUNET_DISK_PipeHandle *p,
                         enum GNUNET_DISK_PipeEnd n)
{
  switch (n)
  {
  case GNUNET_DISK_PIPE_END_READ:
  case GNUNET_DISK_PIPE_END_WRITE:
    return p->fd[n];
  default:
    GNUNET_break (0);
    return NULL;
  }
}


/**
 * Retrieve OS file handle
 * @internal
 * @param fh GNUnet file descriptor
 * @param dst destination buffer
 * @param dst_len length of dst
 * @return #GNUNET_OK on success, #GNUNET_SYSERR otherwise
 */
int
GNUNET_DISK_internal_file_handle_ (const struct GNUNET_DISK_FileHandle *fh,
                                   void *dst, size_t dst_len)
{
  if (NULL == fh)
    return GNUNET_SYSERR;
#ifdef MINGW
  if (dst_len < sizeof (HANDLE))
    return GNUNET_SYSERR;
  *((HANDLE *) dst) = fh->h;
#else
  if (dst_len < sizeof (int))
    return GNUNET_SYSERR;
  *((int *) dst) = fh->fd;
#endif

  return GNUNET_OK;
}

/* end of disk.c */
