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1 | /* -*-c-*- |
2 | * |
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3 | * Locked memory allocation |
4 | * |
5 | * (c) 1999 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
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16 | * |
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17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | #ifndef CATACOMB_LMEM_H |
29 | #define CATACOMB_LMEM_H |
30 | |
31 | #ifdef __cplusplus |
32 | extern "C" { |
33 | #endif |
34 | |
35 | /*----- Header files ------------------------------------------------------*/ |
36 | |
37 | #include <stddef.h> |
38 | |
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39 | #include <mLib/arena.h> |
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40 | #include <mLib/dstr.h> |
41 | |
42 | /*----- Data structures ---------------------------------------------------*/ |
43 | |
44 | /* --- Block list --- * |
45 | * |
46 | * The block list is kept in normal memory, to avoid wasting precious locked |
47 | * memory. Entries are sorted into ascending address order to make |
48 | * coalescing free blocks easier. All blocks, free or not, are included in |
49 | * the list. |
50 | */ |
51 | |
52 | typedef struct l_node { |
53 | struct l_node *next; /* Next free block in chain */ |
54 | char *p; /* Pointer to the block */ |
55 | size_t sz; /* Size of the block */ |
56 | unsigned f; /* Various flags */ |
57 | } l_node; |
58 | |
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59 | #define LF_ALLOC 1u |
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60 | |
61 | /* --- Locked memory buffer state --- */ |
62 | |
63 | typedef struct lmem { |
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64 | arena a; /* Arena header block */ |
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65 | unsigned f; /* Various flags */ |
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66 | char *p; /* Pointer to locked buffer */ |
67 | l_node *l; /* Pointer to block list */ |
68 | size_t sz; /* Size of locked buffer */ |
69 | size_t free; /* Size of free area */ |
70 | int err; char *emsg; /* Error indicators */ |
71 | } lmem; |
72 | |
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73 | #define LF_LOCKED 1u |
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74 | |
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75 | /*----- Functions provided ------------------------------------------------*/ |
76 | |
77 | /* --- @l_init@ --- * |
78 | * |
79 | * Arguments: @lmem *lm@ = pointer to locked memory descriptor |
80 | * @size_t sz@ = size of locked memory area requested |
81 | * |
82 | * Returns: Zero if everything is fine, @+1@ if some insecure memory was |
83 | * allocated, and @-1@ if everything went horribly wrong. |
84 | * |
85 | * Use: Initializes the locked memory manager. This function is safe |
86 | * to call in a privileged program; privileges should usually be |
87 | * dropped after allocating the locked memory block. |
88 | * |
89 | * You must call @sub_init@ before allocating locked memory |
90 | * buffers. |
91 | */ |
92 | |
93 | extern int l_init(lmem */*lm*/, size_t /*sz*/); |
94 | |
95 | /* --- @l_alloc@ --- * |
96 | * |
97 | * Arguments: @lmem *lm@ = pointer to locked memory descriptor |
98 | * @size_t sz@ = size requested |
99 | * |
100 | * Returns: Pointer to allocated memory. |
101 | * |
102 | * Use: Allocates @sz@ bytes of locked memory. |
103 | */ |
104 | |
105 | extern void *l_alloc(lmem */*lm*/, size_t /*sz*/); |
106 | |
107 | /* --- @l_free@ --- * |
108 | * |
109 | * Arguments: @lmem *lm@ = pointer to locked memory descriptor |
110 | * @void *p@ = pointer to block |
111 | * |
112 | * Returns: --- |
113 | * |
114 | * Use: Releases a block of locked memory. |
115 | */ |
116 | |
117 | extern void l_free(lmem */*lm*/, void */*p*/); |
118 | |
119 | /* --- @l_purge@ --- * |
120 | * |
121 | * Arguments: @lmem *lm@ = pointer to locked memory descriptor |
122 | * |
123 | * Returns: --- |
124 | * |
125 | * Use: Purges all the free blocks in the buffer, and clears all of |
126 | * the locked memory. Memory is not freed back to the system. |
127 | */ |
128 | |
129 | extern void l_purge(lmem */*lm*/); |
130 | |
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131 | /* --- @l_destroy@ --- * |
132 | * |
133 | * Arguments: @lmem *lm@ = pointer to locked memory descriptor |
134 | * |
135 | * Returns: --- |
136 | * |
137 | * Use: Disposes of a locked memory arena permanently. |
138 | */ |
139 | |
140 | extern void l_destroy(lmem */*lm*/); |
141 | |
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142 | /* --- @l_report@ --- * |
143 | * |
144 | * Arguments: @lmem *lm@ = pointer to locked memory descriptor |
145 | * @dstr *d@ = string to write the error message on |
146 | * |
147 | * Returns: Zero if the buffer is fine, @+1@ if there was a problem |
148 | * getting locked memory but insecure stuff could be allocated, |
149 | * and @-1@ if not even insecure memory could be found. |
150 | * |
151 | * Use: Returns a user-digestable explanation for the state of a |
152 | * locked memory buffer. If the return code is zero, no message |
153 | * is emitted to the string @d@. |
154 | */ |
155 | |
156 | extern int l_report(lmem */*lm*/, dstr */*d*/); |
157 | |
158 | /*----- That's all, folks -------------------------------------------------*/ |
159 | |
160 | #ifdef __cplusplus |
161 | } |
162 | #endif |
163 | |
164 | #endif |