1 /*
2 * Copyright (C) 2019 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 #define LOG_TAG "bootcontrolhal"
18
19 #include "GptUtils.h"
20
21 #include <errno.h>
22 #include <log/log.h>
23 #include <android-base/file.h>
24 #include <linux/fs.h>
25 #include <zlib.h>
26
27 namespace android {
28 namespace hardware {
29 namespace boot {
30 namespace V1_0 {
31 namespace implementation {
32
33 namespace {
34
ValidateGptHeader(gpt_header * gpt)35 static int ValidateGptHeader(gpt_header *gpt)
36 {
37 if (gpt->signature != GPT_SIGNATURE) {
38 ALOGE("invalid gpt signature 0x%lx\n", gpt->signature);
39 return -1;
40 }
41
42 if (gpt->header_size != sizeof(gpt_header)) {
43 ALOGE("invalid gpt header size %u\n", gpt->header_size);
44 return -1;
45 }
46
47 if (gpt->entry_size != sizeof(gpt_entry)) {
48 ALOGE("invalid gpt entry size %u\n", gpt->entry_size);
49 return -1;
50 }
51
52 return 0;
53 }
54
55 }
56
GptUtils(const std::string dev_path)57 GptUtils::GptUtils(const std::string dev_path) : dev_path(dev_path), fd(0) {}
58
Load(void)59 int GptUtils::Load(void)
60 {
61 fd = open(dev_path.c_str(), O_RDWR);
62 if (fd < 0) {
63 ALOGE("failed to open block dev %s, %d\n", dev_path.c_str(), errno);
64 return -1;
65 }
66
67 int ret = ioctl(fd, BLKSSZGET, &block_size);
68 if (ret < 0) {
69 ALOGE("failed to get block size %d\n", errno);
70 return -1;
71 }
72
73 // read primary header
74 lseek64(fd, block_size, SEEK_SET);
75 ret = read(fd, &gpt_primary, sizeof gpt_primary);
76 if (ret < 0) {
77 ALOGE("failed to read gpt primary header %d\n", errno);
78 return -1;
79 }
80
81 if (ValidateGptHeader(&gpt_primary)) {
82 ALOGE("error validating gpt header\n");
83 return -1;
84 }
85
86 // read partition entries
87 entry_array.resize(gpt_primary.entry_count);
88 uint32_t entries_size = gpt_primary.entry_size * gpt_primary.entry_count;
89 lseek64(fd, block_size * gpt_primary.start_lba, SEEK_SET);
90 ret = read(fd, entry_array.data(), entries_size);
91 if (ret < 0) {
92 ALOGE("failed to read gpt partition entries %d\n", errno);
93 return -1;
94 }
95
96 // read gpt back header
97 lseek64(fd, block_size * gpt_primary.backup_lba, SEEK_SET);
98 ret = read(fd, &gpt_backup, sizeof gpt_backup);
99 if (ret < 0) {
100 ALOGE("failed to read gpt backup header %d\n", errno);
101 return -1;
102 }
103
104 if (ValidateGptHeader(&gpt_backup)) {
105 ALOGW("error validating gpt backup\n"); // just warn about it, not fail
106 }
107
108 // Create map <partition name, gpt_entry pointer>
109 auto get_name = [](const uint16_t *efi_name) {
110 char name[37] = {};
111 for (int i = 0; efi_name[i] && i < sizeof name - 1; ++i)
112 name[i] = efi_name[i];
113 return std::string(name);
114 };
115
116 for (auto const &e: entry_array) {
117 if (e.name[0] == 0)
118 break; // stop at the first partition with no name
119 std::string s = get_name(e.name);
120 entries[s] = const_cast<gpt_entry *>(&e);
121 }
122
123 return 0;
124 }
125
GetPartitionEntry(std::string name)126 gpt_entry *GptUtils::GetPartitionEntry(std::string name)
127 {
128 return entries.find(name) != entries.end() ? entries[name] : nullptr;
129 }
130
Sync(void)131 int GptUtils::Sync(void)
132 {
133 if (!fd)
134 return -1;
135
136 // calculate crc and check if we need to update gpt
137 gpt_primary.entries_crc32 = crc32(0, reinterpret_cast<uint8_t *>(entry_array.data()),
138 entry_array.size() * sizeof(gpt_entry));
139
140 // save old crc
141 uint32_t crc = gpt_primary.crc32;
142 gpt_primary.crc32 = 0;
143
144 gpt_primary.crc32 = crc32(0, reinterpret_cast<uint8_t *>(&gpt_primary), sizeof gpt_primary);
145 if (crc == gpt_primary.crc32)
146 return 0; // nothing to do (no changes)
147
148 ALOGI("updating GPT\n");
149
150 lseek64(fd, block_size * gpt_primary.current_lba, SEEK_SET);
151 int ret = write(fd, &gpt_primary, sizeof gpt_primary);
152 if (ret < 0) {
153 ALOGE("failed to write gpt primary header %d\n", errno);
154 return -1;
155 }
156
157 lseek64(fd, block_size * gpt_primary.start_lba, SEEK_SET);
158 ret = write(fd, entry_array.data(), entry_array.size() * sizeof(gpt_entry));
159 if (ret < 0) {
160 ALOGE("failed to write gpt partition entries %d\n", errno);
161 return -1;
162 }
163
164 //update GPT backup entries and backup
165 lseek64(fd, block_size * gpt_backup.start_lba, SEEK_SET);
166 ret = write(fd, entry_array.data(), entry_array.size() * sizeof(gpt_entry));
167 if (ret < 0) {
168 ALOGE("failed to write gpt backup partition entries %d\n", errno);
169 return -1;
170 }
171
172 gpt_backup.entries_crc32 = gpt_primary.entries_crc32;
173 gpt_backup.crc32 = 0;
174 gpt_backup.crc32 = crc32(0, reinterpret_cast<uint8_t *>(&gpt_backup), sizeof gpt_backup);
175 lseek64(fd, block_size * gpt_primary.backup_lba, SEEK_SET);
176 ret = write(fd, &gpt_backup, sizeof gpt_backup);
177 if (ret < 0) {
178 ALOGE("failed to write gpt backup header %d\n", errno);
179 return -1;
180 }
181
182 fsync(fd);
183
184 return 0;
185 }
186
~GptUtils()187 GptUtils::~GptUtils()
188 {
189 if (fd) {
190 Sync();
191 close(fd);
192 }
193 }
194
195 } // namespace implementation
196 } // namespace V1_0
197 } // namespace boot
198 } // namespace hardware
199 } // namespace android
200