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Diffstat (limited to 'fid.h')
| -rw-r--r-- | fid.h | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/fid.h b/fid.h new file mode 100644 index 0000000000000..cdfdd7ec93d00 --- /dev/null +++ b/fid.h @@ -0,0 +1,160 @@ +/* + * 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 */ |