fusexmp_fh.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.

  gcc -Wall `pkg-config fuse --cflags --libs` -lulockmgr fusexmp_fh.c -o fusexmp_fh
*/

#define FUSE_USE_VERSION 26

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#define _GNU_SOURCE

#include <fuse.h>
#include <ulockmgr.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <sys/time.h>
#ifdef HAVE_SETXATTR
#include <sys/xattr.h>
#endif

static int
xmp_getattr (const char *path, struct stat *stbuf)
{
  int res;

  res = lstat (path, stbuf);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_fgetattr (const char *path, struct stat *stbuf, struct fuse_file_info *fi)
{
  int res;

  (void) path;

  res = fstat (fi->fh, stbuf);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_access (const char *path, int mask)
{
  int res;

  res = access (path, mask);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_readlink (const char *path, char *buf, size_t size)
{
  int res;

  res = readlink (path, buf, size - 1);
  if (res == -1)
    return -errno;

  buf[res] = '\0';
  return 0;
}

struct xmp_dirp
{
  DIR *dp;
  struct dirent *entry;
  off_t offset;
};

static int
xmp_opendir (const char *path, struct fuse_file_info *fi)
{
  int res;
  struct xmp_dirp *d = malloc (sizeof (struct xmp_dirp));

  if (d == NULL)
    return -ENOMEM;

  d->dp = opendir (path);
  if (d->dp == NULL)
    {
      res = -errno;
      free (d);
      return res;
    }
  d->offset = 0;
  d->entry = NULL;

  fi->fh = (unsigned long) d;
  return 0;
}

static inline struct xmp_dirp *
get_dirp (struct fuse_file_info *fi)
{
  return (struct xmp_dirp *) (uintptr_t) fi->fh;
}

static int
xmp_readdir (const char *path, void *buf, fuse_fill_dir_t filler,
             off_t offset, struct fuse_file_info *fi)
{
  struct xmp_dirp *d = get_dirp (fi);

  (void) path;
  if (offset != d->offset)
    {
      seekdir (d->dp, offset);
      d->entry = NULL;
      d->offset = offset;
    }
  while (1)
    {
      struct stat st;
      off_t nextoff;

      if (!d->entry)
        {
          d->entry = readdir (d->dp);
          if (!d->entry)
            break;
        }

      memset (&st, 0, sizeof (st));
      st.st_ino = d->entry->d_ino;
      st.st_mode = d->entry->d_type << 12;
      nextoff = telldir (d->dp);
      if (filler (buf, d->entry->d_name, &st, nextoff))
        break;

      d->entry = NULL;
      d->offset = nextoff;
    }

  return 0;
}

static int
xmp_releasedir (const char *path, struct fuse_file_info *fi)
{
  struct xmp_dirp *d = get_dirp (fi);

  (void) path;
  closedir (d->dp);
  free (d);
  return 0;
}

static int
xmp_mknod (const char *path, mode_t mode, dev_t rdev)
{
  int res;

  if (S_ISFIFO (mode))
    res = mkfifo (path, mode);
  else
    res = mknod (path, mode, rdev);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_mkdir (const char *path, mode_t mode)
{
  int res;

  res = mkdir (path, mode);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_unlink (const char *path)
{
  int res;

  res = unlink (path);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_rmdir (const char *path)
{
  int res;

  res = rmdir (path);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_symlink (const char *from, const char *to)
{
  int res;

  res = symlink (from, to);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_rename (const char *from, const char *to)
{
  int res;

  res = rename (from, to);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_link (const char *from, const char *to)
{
  int res;

  res = link (from, to);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_chmod (const char *path, mode_t mode)
{
  int res;

  res = chmod (path, mode);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_chown (const char *path, uid_t uid, gid_t gid)
{
  int res;

  res = lchown (path, uid, gid);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_truncate (const char *path, off_t size)
{
  int res;

  res = truncate (path, size);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_ftruncate (const char *path, off_t size, struct fuse_file_info *fi)
{
  int res;

  (void) path;

  res = ftruncate (fi->fh, size);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_utimens (const char *path, const struct timespec ts[2])
{
  int res;
  struct timeval tv[2];

  tv[0].tv_sec = ts[0].tv_sec;
  tv[0].tv_usec = ts[0].tv_nsec / 1000;
  tv[1].tv_sec = ts[1].tv_sec;
  tv[1].tv_usec = ts[1].tv_nsec / 1000;

  res = utimes (path, tv);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_create (const char *path, mode_t mode, struct fuse_file_info *fi)
{
  int fd;

  fd = open (path, fi->flags, mode);
  if (fd == -1)
    return -errno;

  fi->fh = fd;
  return 0;
}

static int
xmp_open (const char *path, struct fuse_file_info *fi)
{
  int fd;

  fd = open (path, fi->flags);
  if (fd == -1)
    return -errno;

  fi->fh = fd;
  return 0;
}

static int
xmp_read (const char *path, char *buf, size_t size, off_t offset,
          struct fuse_file_info *fi)
{
  int res;

  (void) path;
  res = pread (fi->fh, buf, size, offset);
  if (res == -1)
    res = -errno;

  return res;
}

static int
xmp_write (const char *path, const char *buf, size_t size,
           off_t offset, struct fuse_file_info *fi)
{
  int res;

  (void) path;
  res = pwrite (fi->fh, buf, size, offset);
  if (res == -1)
    res = -errno;

  return res;
}

static int
xmp_statfs (const char *path, struct statvfs *stbuf)
{
  int res;

  res = statvfs (path, stbuf);
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_flush (const char *path, struct fuse_file_info *fi)
{
  int res;

  (void) path;
  /* This is called from every close on an open file, so call the
     close on the underlying filesystem.  But since flush may be
     called multiple times for an open file, this must not really
     close the file.  This is important if used on a network
     filesystem like NFS which flush the data/metadata on close() */
  res = close (dup (fi->fh));
  if (res == -1)
    return -errno;

  return 0;
}

static int
xmp_release (const char *path, struct fuse_file_info *fi)
{
  (void) path;
  close (fi->fh);

  return 0;
}

static int
xmp_fsync (const char *path, int isdatasync, struct fuse_file_info *fi)
{
  int res;

  (void) path;

#ifndef HAVE_FDATASYNC
  (void) isdatasync;
#else
  if (isdatasync)
    res = fdatasync (fi->fh);
  else
#endif
    res = fsync (fi->fh);
  if (res == -1)
    return -errno;

  return 0;
}

#ifdef HAVE_SETXATTR
/* xattr operations are optional and can safely be left unimplemented */
static int
xmp_setxattr (const char *path, const char *name, const char *value,
              size_t size, int flags)
{
  int res = lsetxattr (path, name, value, size, flags);

  if (res == -1)
    return -errno;
  return 0;
}

static int
xmp_getxattr (const char *path, const char *name, char *value, size_t size)
{
  int res = lgetxattr (path, name, value, size);

  if (res == -1)
    return -errno;
  return res;
}

static int
xmp_listxattr (const char *path, char *list, size_t size)
{
  int res = llistxattr (path, list, size);

  if (res == -1)
    return -errno;
  return res;
}

static int
xmp_removexattr (const char *path, const char *name)
{
  int res = lremovexattr (path, name);

  if (res == -1)
    return -errno;
  return 0;
}
#endif /* HAVE_SETXATTR */

static int
xmp_lock (const char *path, struct fuse_file_info *fi, int cmd,
          struct flock *lock)
{
  (void) path;

  return ulockmgr_op (fi->fh, cmd, lock, &fi->lock_owner,
                      sizeof (fi->lock_owner));
}

static struct fuse_operations xmp_oper = {
  .getattr = xmp_getattr,
  .fgetattr = xmp_fgetattr,
  .access = xmp_access,
  .readlink = xmp_readlink,
  .opendir = xmp_opendir,
  .readdir = xmp_readdir,
  .releasedir = xmp_releasedir,
  .mknod = xmp_mknod,
  .mkdir = xmp_mkdir,
  .symlink = xmp_symlink,
  .unlink = xmp_unlink,
  .rmdir = xmp_rmdir,
  .rename = xmp_rename,
  .link = xmp_link,
  .chmod = xmp_chmod,
  .chown = xmp_chown,
  .truncate = xmp_truncate,
  .ftruncate = xmp_ftruncate,
  .utimens = xmp_utimens,
  .create = xmp_create,
  .open = xmp_open,
  .read = xmp_read,
  .write = xmp_write,
  .statfs = xmp_statfs,
  .flush = xmp_flush,
  .release = xmp_release,
  .fsync = xmp_fsync,
#ifdef HAVE_SETXATTR
  .setxattr = xmp_setxattr,
  .getxattr = xmp_getxattr,
  .listxattr = xmp_listxattr,
  .removexattr = xmp_removexattr,
#endif
  .lock = xmp_lock,

  .flag_nullpath_ok = 1,
};

int
main (int argc, char *argv[])
{
  umask (0);
  return fuse_main (argc, argv, &xmp_oper, NULL);
}