disk.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2001--2013, 2016, 2018 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
*/
#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)

#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


struct GNUNET_DISK_PipeHandle
{
  struct GNUNET_DISK_FileHandle *fd[2];
};


struct GetFileSizeData
{
  uint64_t total;

  int include_sym_links;

  int single_file_mode;
};


#ifndef MINGW

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


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;
}


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
}

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;
}


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
}


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;
}


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;
}


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;
}

void
GNUNET_DISK_fix_permissions (const char *fn,
                             int require_uid_match,
                             int require_gid_match)
{
  /* nothing on W32 */
}

#else

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

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;
}


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);
}


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;
}


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_INFO,
         "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;
}


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;
}


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)
  {
    GNUNET_break (0);
    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_log (GNUNET_ERROR_TYPE_ERROR,
                    "Creating directory `%s' failed",
                    rdir);
        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_log (GNUNET_ERROR_TYPE_ERROR,
                    "Creating directory `%s' failed",
                    rdir);
        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;
}


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;
  }
  if (0 == ACCESS (rdir, W_OK))
  {
    GNUNET_free (rdir);
    return GNUNET_OK;
  }

  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;
}


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
}


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
}


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;
}


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
}


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
}


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;
}


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;
}


static int
remove_helper (void *unused,
               const char *fn)
{
  (void) unused;
  (void) GNUNET_DISK_directory_remove (fn);
  return GNUNET_OK;
}


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;
}


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))
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                              "stat",
                              src);
    return GNUNET_SYSERR;
  }
  pos = 0;
  in = GNUNET_DISK_file_open (src,
                              GNUNET_DISK_OPEN_READ,
                              GNUNET_DISK_PERM_NONE);
  if (! in)
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                              "open",
                              src);
    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_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                              "open",
                              dst);
    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;
}


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 = '_';
    }
  }
}



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;
}


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
}


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
}


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(GNUNET_NO == GNUNET_DISK_file_test(fn))
   {
      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;
}


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

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)
  {
    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

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;
}


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);
}


struct GNUNET_DISK_MapHandle
{
  void *addr;

#ifdef MINGW

  HANDLE h;
#else

  size_t len;
#endif
};


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

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 (NULL == h)
  {
    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
}

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;
}


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


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
}


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;
}


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;
}

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;
}


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;
}


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;
  }
}


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;
}


static int
purge_cfg_dir (void *cls,
               const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  const char *option = cls;
  char *tmpname;

  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (cfg,
                                               "PATHS",
                                               option,
                                               &tmpname))
  {
    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                               "PATHS",
                               option);
    return GNUNET_NO;
  }
  if (GNUNET_SYSERR ==
      GNUNET_DISK_directory_remove (tmpname))
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                              "remove",
                              tmpname);
    GNUNET_free (tmpname);
    return GNUNET_OK;
  }
  GNUNET_free (tmpname);
  return GNUNET_OK;
}


void
GNUNET_DISK_purge_cfg_dir (const char *cfg_filename,
                           const char *option)
{
  GNUNET_break (GNUNET_OK ==
                GNUNET_CONFIGURATION_parse_and_run (cfg_filename,
                                                    &purge_cfg_dir,
                                                    (void *) option));
}


/* end of disk.c */