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 <android-base/file.h>
22 #include <errno.h>
23 #include <linux/fs.h>
24 #include <log/log.h>
25 #include <zlib.h>
26
27 namespace android {
28 namespace hardware {
29 namespace boot {
30 namespace V1_2 {
31 namespace implementation {
32
33 namespace {
34
ValidateGptHeader(gpt_header * gpt)35 static int ValidateGptHeader(gpt_header *gpt) {
36 if (gpt->signature != GPT_SIGNATURE) {
37 ALOGE("invalid gpt signature 0x%lx\n", gpt->signature);
38 return -1;
39 }
40
41 if (gpt->header_size != sizeof(gpt_header)) {
42 ALOGE("invalid gpt header size %u\n", gpt->header_size);
43 return -1;
44 }
45
46 if (gpt->entry_size != sizeof(gpt_entry)) {
47 ALOGE("invalid gpt entry size %u\n", gpt->entry_size);
48 return -1;
49 }
50
51 return 0;
52 }
53
54 } // namespace
55
GptUtils(const std::string dev_path)56 GptUtils::GptUtils(const std::string dev_path) : dev_path(dev_path), fd(0) {}
57
Load(void)58 int GptUtils::Load(void) {
59 fd = open(dev_path.c_str(), O_RDWR);
60 if (fd < 0) {
61 ALOGE("failed to open block dev %s, %d\n", dev_path.c_str(), errno);
62 return -1;
63 }
64
65 int ret = ioctl(fd, BLKSSZGET, &block_size);
66 if (ret < 0) {
67 ALOGE("failed to get block size %d\n", errno);
68 return -1;
69 }
70
71 // read primary header
72 lseek64(fd, block_size, SEEK_SET);
73 ret = read(fd, &gpt_primary, sizeof gpt_primary);
74 if (ret < 0) {
75 ALOGE("failed to read gpt primary header %d\n", errno);
76 return -1;
77 }
78
79 if (ValidateGptHeader(&gpt_primary)) {
80 ALOGE("error validating gpt header\n");
81 return -1;
82 }
83
84 // read partition entries
85 entry_array.resize(gpt_primary.entry_count);
86 uint32_t entries_size = gpt_primary.entry_size * gpt_primary.entry_count;
87 lseek64(fd, block_size * gpt_primary.start_lba, SEEK_SET);
88 ret = read(fd, entry_array.data(), entries_size);
89 if (ret < 0) {
90 ALOGE("failed to read gpt partition entries %d\n", errno);
91 return -1;
92 }
93
94 // read gpt back header
95 lseek64(fd, block_size * gpt_primary.backup_lba, SEEK_SET);
96 ret = read(fd, &gpt_backup, sizeof gpt_backup);
97 if (ret < 0) {
98 ALOGE("failed to read gpt backup header %d\n", errno);
99 return -1;
100 }
101
102 if (ValidateGptHeader(&gpt_backup)) {
103 ALOGW("error validating gpt backup\n"); // just warn about it, not fail
104 }
105
106 // Create map <partition name, gpt_entry pointer>
107 auto get_name = [](const uint16_t *efi_name) {
108 char name[37] = {};
109 for (int i = 0; efi_name[i] && i < sizeof name - 1; ++i) name[i] = efi_name[i];
110 return std::string(name);
111 };
112
113 for (auto const &e : entry_array) {
114 if (e.name[0] == 0)
115 break; // stop at the first partition with no name
116 std::string s = get_name(e.name);
117 entries[s] = const_cast<gpt_entry *>(&e);
118 }
119
120 return 0;
121 }
122
GetPartitionEntry(std::string name)123 gpt_entry *GptUtils::GetPartitionEntry(std::string name) {
124 return entries.find(name) != entries.end() ? entries[name] : nullptr;
125 }
126
Sync(void)127 int GptUtils::Sync(void) {
128 if (!fd)
129 return -1;
130
131 // calculate crc and check if we need to update gpt
132 gpt_primary.entries_crc32 = crc32(0, reinterpret_cast<uint8_t *>(entry_array.data()),
133 entry_array.size() * sizeof(gpt_entry));
134
135 // save old crc
136 uint32_t crc = gpt_primary.crc32;
137 gpt_primary.crc32 = 0;
138
139 gpt_primary.crc32 = crc32(0, reinterpret_cast<uint8_t *>(&gpt_primary), sizeof gpt_primary);
140 if (crc == gpt_primary.crc32)
141 return 0; // nothing to do (no changes)
142
143 ALOGI("updating GPT\n");
144
145 lseek64(fd, block_size * gpt_primary.current_lba, SEEK_SET);
146 int ret = write(fd, &gpt_primary, sizeof gpt_primary);
147 if (ret < 0) {
148 ALOGE("failed to write gpt primary header %d\n", errno);
149 return -1;
150 }
151
152 lseek64(fd, block_size * gpt_primary.start_lba, SEEK_SET);
153 ret = write(fd, entry_array.data(), entry_array.size() * sizeof(gpt_entry));
154 if (ret < 0) {
155 ALOGE("failed to write gpt partition entries %d\n", errno);
156 return -1;
157 }
158
159 // update GPT backup entries and backup
160 lseek64(fd, block_size * gpt_backup.start_lba, SEEK_SET);
161 ret = write(fd, entry_array.data(), entry_array.size() * sizeof(gpt_entry));
162 if (ret < 0) {
163 ALOGE("failed to write gpt backup partition entries %d\n", errno);
164 return -1;
165 }
166
167 gpt_backup.entries_crc32 = gpt_primary.entries_crc32;
168 gpt_backup.crc32 = 0;
169 gpt_backup.crc32 = crc32(0, reinterpret_cast<uint8_t *>(&gpt_backup), sizeof gpt_backup);
170 lseek64(fd, block_size * gpt_primary.backup_lba, SEEK_SET);
171 ret = write(fd, &gpt_backup, sizeof gpt_backup);
172 if (ret < 0) {
173 ALOGE("failed to write gpt backup header %d\n", errno);
174 return -1;
175 }
176
177 fsync(fd);
178
179 return 0;
180 }
181
~GptUtils()182 GptUtils::~GptUtils() {
183 if (fd) {
184 Sync();
185 close(fd);
186 }
187 }
188
189 } // namespace implementation
190 } // namespace V1_2
191 } // namespace boot
192 } // namespace hardware
193 } // namespace android
194