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contrib/lib9p/fid.h
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/* | |||||
* 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 */ |