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