/*
* Copyright 2016 Jakub Klama <jceel@FreeBSD.org>
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted providing that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef LIB9P_FID_H
#define LIB9P_FID_H
#include <stdbool.h>
/*
* Data structure for a fid. All active fids in one session
* are stored in a hash table; the hash table provides the
* iterator to process them. (See also l9p_connection in lib9p.h.)
*
* The back-end code has additional data per fid, found via
* lo_aux. Currently this is allocated with a separate calloc().
*
* Most fids represent a file or directory, but a few are special
* purpose, including the auth fid from Tauth+Tattach, and the
* fids used for extended attributes. We have our own set of
* flags here in lo_flags.
*
* Note that all new fids start as potentially-valid (reserving
* their 32-bit fid value), but not actually-valid. If another
* (threaded) op is invoked on a not-yet-valid fid, the fid cannot
* be used. A fid can also be locked against other threads, in
* which case they must wait for it: this happens during create
* and open, which on success result in the fid changing from a
* directory to a file. (At least, all this applies in principle
* -- we're currently single-threaded per connection so the locks
* are nop-ed out and the valid bit is mainly just for debug.)
*
* Fids that are "open" (the underlying file or directory is open)
* are marked as well.
*
* Locking is managed by the front end (request.c); validation
* and type-marking can be done by either side as needed.
*
* Fid types and validity are manipulated by set* and unset*
* functions, and tested by is* ops. Note that we only
* distinguish between "directory" and "not directory" at this
* level, i.e., symlinks and devices are just "not a directory
* fid". Also, fids cannot be unset as auth or xattr fids,
* nor can an open fid become closed, except by being clunked.
* While files should not normally become directories, it IS normal
* for directory fids to become file fids due to Twalk operations.
*
* (These accessor functions are just to leave wiggle room for
* different future implementations.)
*/
struct l9p_fid {
void *lo_aux;
uint32_t lo_fid;
uint32_t lo_flags; /* volatile atomic_t when threaded? */
};
enum l9p_lo_flags {
L9P_LO_ISAUTH = 0x01,
L9P_LO_ISDIR = 0x02,
L9P_LO_ISOPEN = 0x04,
L9P_LO_ISVALID = 0x08,
L9P_LO_ISXATTR = 0x10,
};
static inline bool
l9p_fid_isauth(struct l9p_fid *fid)
{
return ((fid->lo_flags & L9P_LO_ISAUTH) != 0);
}
static inline void
l9p_fid_setauth(struct l9p_fid *fid)
{
fid->lo_flags |= L9P_LO_ISAUTH;
}
static inline bool
l9p_fid_isdir(struct l9p_fid *fid)
{
return ((fid->lo_flags & L9P_LO_ISDIR) != 0);
}
static inline void
l9p_fid_setdir(struct l9p_fid *fid)
{
fid->lo_flags |= L9P_LO_ISDIR;
}
static inline void
l9p_fid_unsetdir(struct l9p_fid *fid)
{
fid->lo_flags &= ~(uint32_t)L9P_LO_ISDIR;
}
static inline bool
l9p_fid_isopen(struct l9p_fid *fid)
{
return ((fid->lo_flags & L9P_LO_ISOPEN) != 0);
}
static inline void
l9p_fid_setopen(struct l9p_fid *fid)
{
fid->lo_flags |= L9P_LO_ISOPEN;
}
static inline bool
l9p_fid_isvalid(struct l9p_fid *fid)
{
return ((fid->lo_flags & L9P_LO_ISVALID) != 0);
}
static inline void
l9p_fid_setvalid(struct l9p_fid *fid)
{
fid->lo_flags |= L9P_LO_ISVALID;
}
static inline void
l9p_fid_unsetvalid(struct l9p_fid *fid)
{
fid->lo_flags &= ~(uint32_t)L9P_LO_ISVALID;
}
static inline bool
l9p_fid_isxattr(struct l9p_fid *fid)
{
return ((fid->lo_flags & L9P_LO_ISXATTR) != 0);
}
static inline void
l9p_fid_setxattr(struct l9p_fid *fid)
{
fid->lo_flags |= L9P_LO_ISXATTR;
}
#endif /* LIB9P_FID_H */
