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 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 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 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 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