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 */
74 struct l9p_fid {
75 void *lo_aux;
76 uint32_t lo_fid;
77 uint32_t lo_flags; /* volatile atomic_t when threaded? */
78 };
79
80 enum 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
88 static inline bool
l9p_fid_isauth(struct l9p_fid * fid)89 l9p_fid_isauth(struct l9p_fid *fid)
90 {
91 return ((fid->lo_flags & L9P_LO_ISAUTH) != 0);
92 }
93
94 static inline void
l9p_fid_setauth(struct l9p_fid * fid)95 l9p_fid_setauth(struct l9p_fid *fid)
96 {
97 fid->lo_flags |= L9P_LO_ISAUTH;
98 }
99
100 static inline bool
l9p_fid_isdir(struct l9p_fid * fid)101 l9p_fid_isdir(struct l9p_fid *fid)
102 {
103 return ((fid->lo_flags & L9P_LO_ISDIR) != 0);
104 }
105
106 static inline void
l9p_fid_setdir(struct l9p_fid * fid)107 l9p_fid_setdir(struct l9p_fid *fid)
108 {
109 fid->lo_flags |= L9P_LO_ISDIR;
110 }
111
112 static inline void
l9p_fid_unsetdir(struct l9p_fid * fid)113 l9p_fid_unsetdir(struct l9p_fid *fid)
114 {
115 fid->lo_flags &= ~(uint32_t)L9P_LO_ISDIR;
116 }
117
118 static inline bool
l9p_fid_isopen(struct l9p_fid * fid)119 l9p_fid_isopen(struct l9p_fid *fid)
120 {
121 return ((fid->lo_flags & L9P_LO_ISOPEN) != 0);
122 }
123
124 static inline void
l9p_fid_setopen(struct l9p_fid * fid)125 l9p_fid_setopen(struct l9p_fid *fid)
126 {
127 fid->lo_flags |= L9P_LO_ISOPEN;
128 }
129
130 static inline bool
l9p_fid_isvalid(struct l9p_fid * fid)131 l9p_fid_isvalid(struct l9p_fid *fid)
132 {
133 return ((fid->lo_flags & L9P_LO_ISVALID) != 0);
134 }
135
136 static inline void
l9p_fid_setvalid(struct l9p_fid * fid)137 l9p_fid_setvalid(struct l9p_fid *fid)
138 {
139 fid->lo_flags |= L9P_LO_ISVALID;
140 }
141
142 static inline void
l9p_fid_unsetvalid(struct l9p_fid * fid)143 l9p_fid_unsetvalid(struct l9p_fid *fid)
144 {
145 fid->lo_flags &= ~(uint32_t)L9P_LO_ISVALID;
146 }
147
148 static inline bool
l9p_fid_isxattr(struct l9p_fid * fid)149 l9p_fid_isxattr(struct l9p_fid *fid)
150 {
151 return ((fid->lo_flags & L9P_LO_ISXATTR) != 0);
152 }
153
154 static inline void
l9p_fid_setxattr(struct l9p_fid * fid)155 l9p_fid_setxattr(struct l9p_fid *fid)
156 {
157 fid->lo_flags |= L9P_LO_ISXATTR;
158 }
159
160 #endif /* LIB9P_FID_H */
161