1 /*
2
3 Copyright (C) 2000,2004 Silicon Graphics, Inc. All Rights Reserved.
4 Portions Copyright 2002-2010 Sun Microsystems, Inc. All rights reserved.
5
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of version 2.1 of the GNU Lesser General Public License
8 as published by the Free Software Foundation.
9
10 This program is distributed in the hope that it would be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
13
14 Further, this software is distributed without any warranty that it is
15 free of the rightful claim of any third person regarding infringement
16 or the like. Any license provided herein, whether implied or
17 otherwise, applies only to this software file. Patent licenses, if
18 any, provided herein do not apply to combinations of this program with
19 other software, or any other product whatsoever.
20
21 You should have received a copy of the GNU Lesser General Public
22 License along with this program; if not, write the Free Software
23 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston MA 02110-1301,
24 USA.
25
26 Contact information: Silicon Graphics, Inc., 1500 Crittenden Lane,
27 Mountain View, CA 94043, or:
28
29 http://www.sgi.com
30
31 For further information regarding this notice, see:
32
33 http://oss.sgi.com/projects/GenInfo/NoticeExplan
34
35 */
36
37
38
39 #include "config.h"
40 #include "pro_incl.h"
41 #ifdef HAVE_STDLIB_H
42 #include <stdlib.h>
43 #endif /* HAVE_STDLIB_H */
44 #ifdef HAVE_STRING_H
45 #include <string.h>
46 #endif /* HAVE_STRING_H */
47 #include <malloc.h>
48
49 /*
50 When each block is allocated, there is a two-word structure
51 allocated at the beginning so the block can go on a list.
52 The address returned is the address *after* the two pointers
53 at the start. But this allows us to be given a pointer to
54 a generic block, and go backwards to find the list-node. Then
55 we can remove this block from it's list without the need to search
56 through a linked list in order to remove the node. It also allows
57 us to 'delete' a memory block without needing the dbg structure.
58 We still need the dbg structure on allocation so that we know which
59 linked list to add the block to.
60
61 Only the allocation of the dbg structure itself cannot use _dwarf_p_get_alloc.
62 That structure should be set up by hand, and the two list pointers
63 should be initialized to point at the node itself. That initializes
64 the doubly linked list.
65 */
66
67 #define LIST_TO_BLOCK(lst) ((void*) (((char *)lst) + sizeof(memory_list_t)))
68 #define BLOCK_TO_LIST(blk) ((memory_list_t*) (((char*)blk) - sizeof(memory_list_t)))
69
70
71 /*
72 dbg should be NULL only when allocating dbg itself. In that
73 case we initialize it to an empty circular doubly-linked list.
74 */
75
76 Dwarf_Ptr
_dwarf_p_get_alloc(Dwarf_P_Debug dbg,Dwarf_Unsigned size)77 _dwarf_p_get_alloc(Dwarf_P_Debug dbg, Dwarf_Unsigned size)
78 {
79 void *sp;
80 memory_list_t *lp = NULL;
81 memory_list_t *dbglp = NULL;
82 memory_list_t *nextblock = NULL;
83
84 /* alloc control struct and data block together for performance reasons */
85 lp = (memory_list_t *) malloc(size + sizeof(memory_list_t));
86 if (lp == NULL) {
87 /* should throw an error */
88 return NULL;
89 }
90
91 /* point to 'size' bytes just beyond lp struct */
92 sp = LIST_TO_BLOCK(lp);
93 memset(sp, 0, size);
94
95 if (dbg == NULL) {
96 lp->next = lp->prev = lp;
97 } else {
98 /* I always have to draw a picture to understand this part. */
99
100 dbglp = BLOCK_TO_LIST(dbg);
101 nextblock = dbglp->next;
102
103 /* Insert between dbglp and nextblock */
104 dbglp->next = lp;
105 lp->prev = dbglp;
106 lp->next = nextblock;
107 nextblock->prev = lp;
108 }
109
110 return sp;
111 }
112
113 /*
114 This routine is only here in case a caller of an older version of the
115 library is calling this for some reason.
116 We will clean up any stray blocks when the session is closed.
117 No need to remove this block. In theory the user might be
118 depending on the fact that we used to just 'free' this.
119 In theory they might also be
120 passing a block that they got from libdwarf. So we don't know if we
121 should try to remove this block from our global list. Safest just to
122 do nothing at this point.
123
124 !!!
125 This function is deprecated! Don't call it inside libdwarf or outside of it.
126 !!!
127 */
128
129 void
dwarf_p_dealloc(Dwarf_Small * ptr)130 dwarf_p_dealloc(Dwarf_Small * ptr)
131 {
132 return;
133 }
134
135 /*
136 The dbg structure is not needed here anymore.
137 */
138
139 void
_dwarf_p_dealloc(Dwarf_P_Debug dbg,Dwarf_Small * ptr)140 _dwarf_p_dealloc(Dwarf_P_Debug dbg, Dwarf_Small * ptr) /* ARGSUSED */
141 {
142 memory_list_t *lp;
143 lp = BLOCK_TO_LIST(ptr);
144
145 /*
146 Remove from a doubly linked, circular list.
147 Read carefully, use a white board if necessary.
148 If this is an empty list, the following statements are no-ops, and
149 will write to the same memory location they read from.
150 This should only happen when we deallocate the dbg structure itself.
151 */
152
153 lp->prev->next = lp->next;
154 lp->next->prev = lp->prev;
155
156 free((void*)lp);
157 }
158
159
160 /*
161 This routine deallocates all the nodes on the dbg list,
162 and then deallocates the dbg structure itself.
163 */
164
165 void
_dwarf_p_dealloc_all(Dwarf_P_Debug dbg)166 _dwarf_p_dealloc_all(Dwarf_P_Debug dbg)
167 {
168 memory_list_t *dbglp;
169
170 if (dbg == NULL) {
171 /* should throw an error */
172 return;
173 }
174
175 dbglp = BLOCK_TO_LIST(dbg);
176 while (dbglp->next != dbglp) {
177 _dwarf_p_dealloc(dbg, LIST_TO_BLOCK(dbglp->next));
178 }
179 if (dbglp->next != dbglp ||
180 dbglp->prev != dbglp) {
181
182 /* should throw error */
183 /* For some reason we couldn't free all the blocks? */
184 return;
185 }
186 _dwarf_p_dealloc(NULL, (void*)dbg);
187 }
188
189