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/* Definitions for shared IO control pages
Copyright (C) 1991 Free Software Foundation
This file is part of the GNU Hurd.
The GNU Hurd 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 1, or (at your option)
any later version.
The GNU Hurd 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 the GNU Hurd; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
struct shared_io
{
int shared_page_version;
/* This lock protects against modification to it_status. */
spin_lock_t lock;
enum
{
USER_IT, /* User is it */
USER_POTENTIALLY_IT, /* User can become it */
USER_RELEASE_IT, /* User is it, should release it promptly */
USER_NOT_IT, /* User is not it */
} it_status;
/* These values are set by the IO server only: */
int append_mode; /* append on each write */
int eof_notify; /* notify filesystem upon read of eof */
int do_sigio; /* call io_sigio after each operation */
int use_file_size; /* file_size is meaningful */
off_t file_size;
int use_read_size; /* read_size is meaningful */
int read_size;
int seekable; /* the file pointer can be reduced */
int use_prenotify_size; /* prenotify_size is meaningful */
int use_postnotify_size; /* postnotify_size is meaningful */
off_t prenotify_size;
off_t postnotify_size;
/* These are set by both the IO server and the user: */
/* These have meanings just like io_map; -1 is used to indicate an
impossible value. */
off_t rd_file_pointer;
off_t wr_file_pointer;
off_t xx_file_pointer;
/* These are set by the user only: */
/* These two indicate that the appropriate times need updated */
int written;
int accessed;
/* Reserved for future extensions */
int reserved [32];
/* Owned by the user from here to the end of the page */
int user_owned[0];
};
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