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528b2c61 | 1 | /* |
bbc27441 | 2 | * Copyright (C) 1996-2014 The Squid Software Foundation and contributors |
528b2c61 | 3 | * |
bbc27441 AJ |
4 | * Squid software is distributed under GPLv2+ license and includes |
5 | * contributions from numerous individuals and organizations. | |
6 | * Please see the COPYING and CONTRIBUTORS files for details. | |
528b2c61 | 7 | */ |
8 | ||
bbc27441 AJ |
9 | /* DEBUG: section 20 Storage Manager Swapfile Unpacker */ |
10 | ||
582c2af2 | 11 | #include "squid.h" |
582c2af2 | 12 | #include "Debug.h" |
602d9612 | 13 | #include "defines.h" |
528b2c61 | 14 | #include "StoreMeta.h" |
602d9612 | 15 | #include "StoreMetaUnpacker.h" |
528b2c61 | 16 | |
57d55dfa | 17 | int const StoreMetaUnpacker::MinimumBufferLength = sizeof(char) + sizeof(int); |
528b2c61 | 18 | |
e2851fe7 AR |
19 | /// useful for meta stored in pre-initialized (with zeros) db files |
20 | bool | |
21 | StoreMetaUnpacker::isBufferZero() | |
22 | { | |
23 | // We could memcmp the entire buffer, but it is probably safe enough | |
24 | // to test a few bytes because if we do not detect a corrupted entry | |
25 | // it is not a big deal. Empty entries are not isBufferSane anyway. | |
26 | const int depth = 10; | |
27 | if (buflen < depth) | |
28 | return false; // cannot be sure enough | |
29 | ||
30 | for (int i = 0; i < depth; ++i) { | |
31 | if (buf[i]) | |
32 | return false; | |
33 | } | |
34 | return true; | |
35 | } | |
36 | ||
528b2c61 | 37 | bool |
38 | StoreMetaUnpacker::isBufferSane() | |
39 | { | |
40 | if (buf[0] != (char) STORE_META_OK) | |
62e76326 | 41 | return false; |
42 | ||
528b2c61 | 43 | /* |
44 | * sanity check on 'buflen' value. It should be at least big | |
45 | * enough to hold one type and one length. | |
46 | */ | |
47 | getBufferLength(); | |
62e76326 | 48 | |
7c209882 | 49 | if (*hdr_len < MinimumBufferLength) |
62e76326 | 50 | return false; |
51 | ||
528b2c61 | 52 | if (*hdr_len > buflen) |
62e76326 | 53 | return false; |
54 | ||
528b2c61 | 55 | return true; |
56 | } | |
57 | ||
58 | void | |
59 | StoreMetaUnpacker::getBufferLength() | |
60 | { | |
41d00cd3 | 61 | memcpy(hdr_len, &buf[1], sizeof(int)); |
528b2c61 | 62 | } |
63 | ||
64 | StoreMetaUnpacker::StoreMetaUnpacker (char const *aBuffer, ssize_t aLen, int *anInt) : buf (aBuffer), buflen(aLen), hdr_len(anInt), position(1 + sizeof(int)) | |
65 | { | |
66 | assert (aBuffer != NULL); | |
67 | } | |
68 | ||
69 | void | |
70 | StoreMetaUnpacker::getType() | |
71 | { | |
f412b2d6 FC |
72 | type = buf[position]; |
73 | ++position; | |
528b2c61 | 74 | } |
75 | ||
76 | void | |
77 | StoreMetaUnpacker::getLength() | |
78 | { | |
41d00cd3 | 79 | memcpy(&length, &buf[position], sizeof(int)); |
528b2c61 | 80 | position += sizeof(int); |
81 | } | |
82 | ||
83 | bool | |
84 | StoreMetaUnpacker::doOneEntry() | |
85 | { | |
86 | getType(); | |
87 | getLength(); | |
62e76326 | 88 | |
528b2c61 | 89 | if (position + length > *hdr_len) { |
fa84c01d FC |
90 | debugs(20, DBG_CRITICAL, "storeSwapMetaUnpack: overflow!"); |
91 | debugs(20, DBG_CRITICAL, "\ttype=" << type << ", length=" << length << ", *hdr_len=" << *hdr_len << ", offset=" << position); | |
528b2c61 | 92 | return false; |
93 | } | |
62e76326 | 94 | |
528b2c61 | 95 | StoreMeta *newNode = StoreMeta::Factory(type, length, &buf[position]); |
62e76326 | 96 | |
5b8ddb2a | 97 | if (newNode) |
26ac0430 | 98 | tail = StoreMeta::Add (tail, newNode); |
62e76326 | 99 | |
528b2c61 | 100 | position += length; |
62e76326 | 101 | |
528b2c61 | 102 | return true; |
103 | } | |
104 | ||
105 | bool | |
106 | StoreMetaUnpacker::moreToProcess() const | |
107 | { | |
7c209882 | 108 | return *hdr_len - position - MinimumBufferLength >= 0; |
528b2c61 | 109 | } |
110 | ||
111 | StoreMeta * | |
112 | StoreMetaUnpacker::createStoreMeta () | |
113 | { | |
114 | tlv *TLV = NULL; | |
115 | tail = &TLV; | |
116 | assert(hdr_len != NULL); | |
62e76326 | 117 | |
528b2c61 | 118 | if (!isBufferSane()) |
62e76326 | 119 | return NULL; |
120 | ||
528b2c61 | 121 | getBufferLength(); |
62e76326 | 122 | |
528b2c61 | 123 | assert (position == 1 + sizeof(int)); |
62e76326 | 124 | |
528b2c61 | 125 | while (moreToProcess()) { |
62e76326 | 126 | if (!doOneEntry()) |
127 | break; | |
528b2c61 | 128 | } |
62e76326 | 129 | |
528b2c61 | 130 | return TLV; |
131 | } |