1/*
2 * Copyright 2016 Jakub Klama <jceel@FreeBSD.org>
3 * All rights reserved
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted providing that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
18 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
22 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
23 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24 * POSSIBILITY OF SUCH DAMAGE.
25 *
26 */
27
28#ifndef LIB9P_FID_H
29#define LIB9P_FID_H
30
31#include <stdbool.h>
32
33/*
34 * Data structure for a fid.  All active fids in one session
35 * are stored in a hash table; the hash table provides the
36 * iterator to process them.  (See also l9p_connection in lib9p.h.)
37 *
38 * The back-end code has additional data per fid, found via
39 * lo_aux.  Currently this is allocated with a separate calloc().
40 *
41 * Most fids represent a file or directory, but a few are special
42 * purpose, including the auth fid from Tauth+Tattach, and the
43 * fids used for extended attributes.  We have our own set of
44 * flags here in lo_flags.
45 *
46 * Note that all new fids start as potentially-valid (reserving
47 * their 32-bit fid value), but not actually-valid.  If another
48 * (threaded) op is invoked on a not-yet-valid fid, the fid cannot
49 * be used.  A fid can also be locked against other threads, in
50 * which case they must wait for it: this happens during create
51 * and open, which on success result in the fid changing from a
52 * directory to a file.  (At least, all this applies in principle
53 * -- we're currently single-threaded per connection so the locks
54 * are nop-ed out and the valid bit is mainly just for debug.)
55 *
56 * Fids that are "open" (the underlying file or directory is open)
57 * are marked as well.
58 *
59 * Locking is managed by the front end (request.c); validation
60 * and type-marking can be done by either side as needed.
61 *
62 * Fid types and validity are manipulated by set* and unset*
63 * functions, and tested by is* ops.  Note that we only
64 * distinguish between "directory" and "not directory" at this
65 * level, i.e., symlinks and devices are just "not a directory
66 * fid".  Also, fids cannot be unset as auth or xattr fids,
67 * nor can an open fid become closed, except by being clunked.
68 * While files should not normally become directories, it IS normal
69 * for directory fids to become file fids due to Twalk operations.
70 *
71 * (These accessor functions are just to leave wiggle room for
72 * different future implementations.)
73 */
74struct l9p_fid {
75	void	*lo_aux;
76	uint32_t lo_fid;
77	uint32_t lo_flags;	/* volatile atomic_t when threaded? */
78};
79
80enum l9p_lo_flags {
81	L9P_LO_ISAUTH = 0x01,
82	L9P_LO_ISDIR = 0x02,
83	L9P_LO_ISOPEN = 0x04,
84	L9P_LO_ISVALID = 0x08,
85	L9P_LO_ISXATTR = 0x10,
86};
87
88static inline bool
89l9p_fid_isauth(struct l9p_fid *fid)
90{
91	return ((fid->lo_flags & L9P_LO_ISAUTH) != 0);
92}
93
94static inline void
95l9p_fid_setauth(struct l9p_fid *fid)
96{
97	fid->lo_flags |= L9P_LO_ISAUTH;
98}
99
100static inline bool
101l9p_fid_isdir(struct l9p_fid *fid)
102{
103	return ((fid->lo_flags & L9P_LO_ISDIR) != 0);
104}
105
106static inline void
107l9p_fid_setdir(struct l9p_fid *fid)
108{
109	fid->lo_flags |= L9P_LO_ISDIR;
110}
111
112static inline void
113l9p_fid_unsetdir(struct l9p_fid *fid)
114{
115	fid->lo_flags &= ~(uint32_t)L9P_LO_ISDIR;
116}
117
118static inline bool
119l9p_fid_isopen(struct l9p_fid *fid)
120{
121	return ((fid->lo_flags & L9P_LO_ISOPEN) != 0);
122}
123
124static inline void
125l9p_fid_setopen(struct l9p_fid *fid)
126{
127	fid->lo_flags |= L9P_LO_ISOPEN;
128}
129
130static inline bool
131l9p_fid_isvalid(struct l9p_fid *fid)
132{
133	return ((fid->lo_flags & L9P_LO_ISVALID) != 0);
134}
135
136static inline void
137l9p_fid_setvalid(struct l9p_fid *fid)
138{
139	fid->lo_flags |= L9P_LO_ISVALID;
140}
141
142static inline void
143l9p_fid_unsetvalid(struct l9p_fid *fid)
144{
145	fid->lo_flags &= ~(uint32_t)L9P_LO_ISVALID;
146}
147
148static inline bool
149l9p_fid_isxattr(struct l9p_fid *fid)
150{
151	return ((fid->lo_flags & L9P_LO_ISXATTR) != 0);
152}
153
154static inline void
155l9p_fid_setxattr(struct l9p_fid *fid)
156{
157	fid->lo_flags |= L9P_LO_ISXATTR;
158}
159
160#endif  /* LIB9P_FID_H */
161