1 /*
2 * Copyright (C) 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "idmap2/BinaryStreamVisitor.h"
18
19 #include <algorithm>
20 #include <cstring>
21 #include <string>
22
23 #include "android-base/macros.h"
24
25 namespace android::idmap2 {
26
Write8(uint8_t value)27 void BinaryStreamVisitor::Write8(uint8_t value) {
28 stream_.write(reinterpret_cast<char*>(&value), sizeof(uint8_t));
29 }
30
Write16(uint16_t value)31 void BinaryStreamVisitor::Write16(uint16_t value) {
32 uint16_t x = htodl(value);
33 stream_.write(reinterpret_cast<char*>(&x), sizeof(uint16_t));
34 }
35
Write32(uint32_t value)36 void BinaryStreamVisitor::Write32(uint32_t value) {
37 uint32_t x = htodl(value);
38 stream_.write(reinterpret_cast<char*>(&x), sizeof(uint32_t));
39 }
40
WriteString(StringPiece value)41 void BinaryStreamVisitor::WriteString(StringPiece value) {
42 // pad with null to nearest word boundary;
43 size_t padding_size = CalculatePadding(value.size());
44 Write32(value.size());
45 stream_.write(value.data(), value.size());
46 stream_.write("\0\0\0\0", padding_size);
47 }
48
visit(const Idmap & idmap ATTRIBUTE_UNUSED)49 void BinaryStreamVisitor::visit(const Idmap& idmap ATTRIBUTE_UNUSED) {
50 // nothing to do
51 }
52
visit(const IdmapHeader & header)53 void BinaryStreamVisitor::visit(const IdmapHeader& header) {
54 Write32(header.GetMagic());
55 Write32(header.GetVersion());
56 Write32(header.GetTargetCrc());
57 Write32(header.GetOverlayCrc());
58 Write32(header.GetFulfilledPolicies());
59 Write32(static_cast<uint8_t>(header.GetEnforceOverlayable()));
60 WriteString(header.GetTargetPath());
61 WriteString(header.GetOverlayPath());
62 WriteString(header.GetOverlayName());
63 WriteString(header.GetDebugInfo());
64 }
65
visit(const IdmapData & data)66 void BinaryStreamVisitor::visit(const IdmapData& data) {
67 for (const auto& target_entry : data.GetTargetEntries()) {
68 Write32(target_entry.target_id);
69 }
70 for (const auto& target_entry : data.GetTargetEntries()) {
71 Write32(target_entry.overlay_id);
72 }
73
74 uint32_t current_inline_entry_values_count = 0;
75 for (const auto& target_inline_entry : data.GetTargetInlineEntries()) {
76 Write32(target_inline_entry.target_id);
77 }
78 for (const auto& target_inline_entry : data.GetTargetInlineEntries()) {
79 Write32(current_inline_entry_values_count);
80 Write32(target_inline_entry.values.size());
81 current_inline_entry_values_count += target_inline_entry.values.size();
82 }
83
84 std::vector<ConfigDescription> configs;
85 configs.reserve(data.GetHeader()->GetConfigCount());
86 for (const auto& target_entry : data.GetTargetInlineEntries()) {
87 for (const auto& target_entry_value : target_entry.values) {
88 auto config_it = std::find(configs.begin(), configs.end(), target_entry_value.first);
89 if (config_it != configs.end()) {
90 Write32(config_it - configs.begin());
91 } else {
92 Write32(configs.size());
93 configs.push_back(target_entry_value.first);
94 }
95 // We're writing a Res_value entry here, and the first 3 bytes of that are
96 // sizeof() + a padding 0 byte
97 static constexpr decltype(android::Res_value::size) kSize = sizeof(android::Res_value);
98 Write16(kSize);
99 Write8(0U);
100 Write8(target_entry_value.second.data_type);
101 Write32(target_entry_value.second.data_value);
102 }
103 }
104
105 if (!configs.empty()) {
106 stream_.write(reinterpret_cast<const char*>(&configs.front()),
107 sizeof(configs.front()) * configs.size());
108 if (configs.size() >= 100) {
109 // Let's write a message to future us so that they know when to replace the linear search
110 // in `configs` vector with something more efficient.
111 LOG(WARNING) << "Idmap got " << configs.size()
112 << " configurations, time to fix the bruteforce search";
113 }
114 }
115
116 for (const auto& overlay_entry : data.GetOverlayEntries()) {
117 Write32(overlay_entry.overlay_id);
118 }
119 for (const auto& overlay_entry : data.GetOverlayEntries()) {
120 Write32(overlay_entry.target_id);
121 }
122
123 WriteString(data.GetStringPoolData());
124 }
125
visit(const IdmapData::Header & header)126 void BinaryStreamVisitor::visit(const IdmapData::Header& header) {
127 Write32(header.GetTargetEntryCount());
128 Write32(header.GetTargetInlineEntryCount());
129 Write32(header.GetTargetInlineEntryValueCount());
130 Write32(header.GetConfigCount());
131 Write32(header.GetOverlayEntryCount());
132 Write32(header.GetStringPoolIndexOffset());
133 }
134
135 } // namespace android::idmap2
136