1 | /* |
2 | * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved. |
3 | * |
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27 | */ |
28 | /* |
29 | * @OSF_COPYRIGHT@ |
30 | */ |
31 | /* |
32 | * Mach Operating System |
33 | * Copyright (c) 1991,1990,1989 Carnegie Mellon University |
34 | * All Rights Reserved. |
35 | * |
36 | * Permission to use, copy, modify and distribute this software and its |
37 | * documentation is hereby granted, provided that both the copyright |
38 | * notice and this permission notice appear in all copies of the |
39 | * software, derivative works or modified versions, and any portions |
40 | * thereof, and that both notices appear in supporting documentation. |
41 | * |
42 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" |
43 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR |
44 | * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. |
45 | * |
46 | * Carnegie Mellon requests users of this software to return to |
47 | * |
48 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU |
49 | * School of Computer Science |
50 | * Carnegie Mellon University |
51 | * Pittsburgh PA 15213-3890 |
52 | * |
53 | * any improvements or extensions that they make and grant Carnegie Mellon |
54 | * the rights to redistribute these changes. |
55 | */ |
56 | /* |
57 | */ |
58 | /* |
59 | * File: ipc/ipc_entry.h |
60 | * Author: Rich Draves |
61 | * Date: 1989 |
62 | * |
63 | * Definitions for translation entries, which represent |
64 | * tasks' capabilities for ports and port sets. |
65 | */ |
66 | |
67 | #ifndef _IPC_IPC_ENTRY_H_ |
68 | #define _IPC_IPC_ENTRY_H_ |
69 | |
70 | #include <mach/mach_types.h> |
71 | #include <mach/port.h> |
72 | #include <mach/kern_return.h> |
73 | |
74 | #include <kern/kern_types.h> |
75 | #include <kern/zalloc.h> |
76 | |
77 | #include <ipc/ipc_types.h> |
78 | |
79 | /* |
80 | * Spaces hold capabilities for ipc_object_t's. |
81 | * Each ipc_entry_t records a capability. Most capabilities have |
82 | * small names, and the entries are elements of a table. |
83 | * |
84 | * The ie_index field of entries in the table implements |
85 | * a ordered hash table with open addressing and linear probing. |
86 | * This hash table converts (space, object) -> name. |
87 | * It is used independently of the other fields. |
88 | * |
89 | * Free (unallocated) entries in the table have null ie_object |
90 | * fields. The ie_bits field is zero except for IE_BITS_GEN. |
91 | * The ie_next (ie_request) field links free entries into a free list. |
92 | * |
93 | * The first entry in the table (index 0) is always free. |
94 | * It is used as the head of the free list. |
95 | */ |
96 | |
97 | struct ipc_entry { |
98 | struct ipc_object *ie_object; |
99 | ipc_entry_bits_t ie_bits; |
100 | mach_port_index_t ie_index; |
101 | union { |
102 | mach_port_index_t next; /* next in freelist, or... */ |
103 | ipc_table_index_t request; /* dead name request notify */ |
104 | } index; |
105 | }; |
106 | |
107 | #define ie_request index.request |
108 | #define ie_next index.next |
109 | |
110 | #define IE_REQ_NONE 0 /* no request */ |
111 | |
112 | #define IE_BITS_UREFS_MASK 0x0000ffff /* 16 bits of user-reference */ |
113 | #define IE_BITS_UREFS(bits) ((bits) & IE_BITS_UREFS_MASK) |
114 | |
115 | #define IE_BITS_TYPE_MASK 0x001f0000 /* 5 bits of capability type */ |
116 | #define IE_BITS_TYPE(bits) ((bits) & IE_BITS_TYPE_MASK) |
117 | |
118 | #ifndef NO_PORT_GEN |
119 | #define IE_BITS_GEN_MASK 0xff000000 /* 8 bits for generation */ |
120 | #define IE_BITS_GEN(bits) ((bits) & IE_BITS_GEN_MASK) |
121 | #define IE_BITS_GEN_ONE 0x04000000 /* low bit of generation */ |
122 | #define IE_BITS_ROLL_POS 22 /* LSB pos of generation rollover */ |
123 | #define IE_BITS_ROLL_BITS 2 /* number of generation rollover bits */ |
124 | #define IE_BITS_ROLL_MASK (((1 << IE_BITS_ROLL_BITS) - 1) << IE_BITS_ROLL_POS) |
125 | #define IE_BITS_ROLL(bits) ((((bits) & IE_BITS_ROLL_MASK) << 8) ^ IE_BITS_GEN_MASK) |
126 | |
127 | /* |
128 | * Restart a generation counter with the specified bits for the rollover point. |
129 | * There are 4 different rollover points: |
130 | * bits rollover period |
131 | * 0 0 64 |
132 | * 0 1 48 |
133 | * 1 0 32 |
134 | * 1 1 16 |
135 | */ |
136 | static inline ipc_entry_bits_t ipc_entry_new_rollpoint( |
137 | ipc_entry_bits_t rollbits) |
138 | { |
139 | rollbits = (rollbits << IE_BITS_ROLL_POS) & IE_BITS_ROLL_MASK; |
140 | ipc_entry_bits_t newgen = IE_BITS_GEN_MASK + IE_BITS_GEN_ONE; |
141 | return (newgen | rollbits); |
142 | } |
143 | |
144 | /* |
145 | * Get the next gencount, modulo the entry's rollover point. If the sum rolls over, |
146 | * the caller should re-start the generation counter with a different rollpoint. |
147 | */ |
148 | static inline ipc_entry_bits_t ipc_entry_new_gen( |
149 | ipc_entry_bits_t oldgen) |
150 | { |
151 | ipc_entry_bits_t sum = (oldgen + IE_BITS_GEN_ONE) & IE_BITS_GEN_MASK; |
152 | ipc_entry_bits_t roll = oldgen & IE_BITS_ROLL_MASK; |
153 | ipc_entry_bits_t newgen = (sum % IE_BITS_ROLL(oldgen)) | roll; |
154 | return newgen; |
155 | } |
156 | |
157 | /* Determine if a gencount has rolled over or not. */ |
158 | static inline boolean_t ipc_entry_gen_rolled( |
159 | ipc_entry_bits_t oldgen, |
160 | ipc_entry_bits_t newgen) |
161 | { |
162 | return (oldgen & IE_BITS_GEN_MASK) > (newgen & IE_BITS_GEN_MASK); |
163 | } |
164 | |
165 | #else |
166 | #define IE_BITS_GEN_MASK 0 |
167 | #define IE_BITS_GEN(bits) 0 |
168 | #define IE_BITS_GEN_ONE 0 |
169 | #define IE_BITS_ROLL_POS 0 |
170 | #define IE_BITS_ROLL_MASK 0 |
171 | #define IE_BITS_ROLL(bits) (bits) |
172 | |
173 | static inline ipc_entry_bits_t ipc_entry_new_rollpoint( |
174 | ipc_entry_bits_t rollbits) |
175 | { |
176 | return 0; |
177 | } |
178 | |
179 | static inline ipc_entry_bits_t ipc_entry_new_gen( |
180 | ipc_entry_bits_t oldgen) |
181 | { |
182 | return 0; |
183 | } |
184 | |
185 | static inline boolean_t ipc_entry_gen_rolled( |
186 | ipc_entry_bits_t oldgen, |
187 | ipc_entry_bits_t newgen) |
188 | { |
189 | return FALSE; |
190 | } |
191 | |
192 | #endif /* !USE_PORT_GEN */ |
193 | |
194 | #define IE_BITS_RIGHT_MASK 0x007fffff /* relevant to the right */ |
195 | /* |
196 | * Exported interfaces |
197 | */ |
198 | |
199 | /* Search for entry in a space by name */ |
200 | extern ipc_entry_t ipc_entry_lookup( |
201 | ipc_space_t space, |
202 | mach_port_name_t name); |
203 | |
204 | /* Hold a number of entries in a locked space */ |
205 | extern kern_return_t ipc_entries_hold( |
206 | ipc_space_t space, |
207 | natural_t count); |
208 | |
209 | /* claim and initialize a held entry in a locked space */ |
210 | extern kern_return_t ipc_entry_claim( |
211 | ipc_space_t space, |
212 | mach_port_name_t *namep, |
213 | ipc_entry_t *entryp); |
214 | |
215 | /* Allocate an entry in a space */ |
216 | extern kern_return_t ipc_entry_get( |
217 | ipc_space_t space, |
218 | mach_port_name_t *namep, |
219 | ipc_entry_t *entryp); |
220 | |
221 | /* Allocate an entry in a space, growing the space if necessary */ |
222 | extern kern_return_t ipc_entry_alloc( |
223 | ipc_space_t space, |
224 | mach_port_name_t *namep, |
225 | ipc_entry_t *entryp); |
226 | |
227 | /* Allocate/find an entry in a space with a specific name */ |
228 | extern kern_return_t ipc_entry_alloc_name( |
229 | ipc_space_t space, |
230 | mach_port_name_t name, |
231 | ipc_entry_t *entryp); |
232 | |
233 | /* Deallocate an entry from a space */ |
234 | extern void ipc_entry_dealloc( |
235 | ipc_space_t space, |
236 | mach_port_name_t name, |
237 | ipc_entry_t entry); |
238 | |
239 | /* Mark and entry modified in a space */ |
240 | extern void ipc_entry_modified( |
241 | ipc_space_t space, |
242 | mach_port_name_t name, |
243 | ipc_entry_t entry); |
244 | |
245 | /* Grow the table in a space */ |
246 | extern kern_return_t ipc_entry_grow_table( |
247 | ipc_space_t space, |
248 | ipc_table_elems_t target_size); |
249 | |
250 | /* mask on/off default entry generation bits */ |
251 | extern mach_port_name_t ipc_entry_name_mask( |
252 | mach_port_name_t name); |
253 | #endif /* _IPC_IPC_ENTRY_H_ */ |
254 | |