1 /*
2 * Copyright (C) 2016 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 "bootloader_message.h"
18
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <string.h>
22
23 #include <string>
24 #include <vector>
25
26 #include <android-base/file.h>
27 #include <android-base/properties.h>
28 #include <android-base/stringprintf.h>
29 #include <android-base/unique_fd.h>
30 #include <fstab/fstab.h>
31
32 using android::fs_mgr::Fstab;
33 using android::fs_mgr::GetEntryForMountPoint;
34 using android::fs_mgr::ReadDefaultFstab;
35
36 constexpr off_t kBootloaderControlOffset = offsetof(bootloader_message_ab, slot_suffix);
37
get_misc_blk_device(std::string * err)38 static std::string get_misc_blk_device(std::string* err) {
39 Fstab fstab;
40 if (!ReadDefaultFstab(&fstab)) {
41 *err = "failed to read default fstab";
42 return "";
43 }
44 auto record = GetEntryForMountPoint(&fstab, "/misc");
45 if (record == nullptr) {
46 *err = "failed to find /misc partition";
47 return "";
48 }
49 return record->blk_device;
50 }
51
52 // In recovery mode, recovery can get started and try to access the misc
53 // device before the kernel has actually created it.
wait_for_device(const std::string & blk_device,std::string * err)54 static bool wait_for_device(const std::string& blk_device, std::string* err) {
55 int tries = 0;
56 int ret;
57 err->clear();
58 do {
59 ++tries;
60 struct stat buf;
61 ret = stat(blk_device.c_str(), &buf);
62 if (ret == -1) {
63 *err += android::base::StringPrintf("failed to stat %s try %d: %s\n",
64 blk_device.c_str(), tries, strerror(errno));
65 sleep(1);
66 }
67 } while (ret && tries < 10);
68
69 if (ret) {
70 *err += android::base::StringPrintf("failed to stat %s\n", blk_device.c_str());
71 }
72 return ret == 0;
73 }
74
read_misc_partition(void * p,size_t size,const std::string & misc_blk_device,size_t offset,std::string * err)75 static bool read_misc_partition(void* p, size_t size, const std::string& misc_blk_device,
76 size_t offset, std::string* err) {
77 if (!wait_for_device(misc_blk_device, err)) {
78 return false;
79 }
80 android::base::unique_fd fd(open(misc_blk_device.c_str(), O_RDONLY));
81 if (fd == -1) {
82 *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(),
83 strerror(errno));
84 return false;
85 }
86 if (lseek(fd, static_cast<off_t>(offset), SEEK_SET) != static_cast<off_t>(offset)) {
87 *err = android::base::StringPrintf("failed to lseek %s: %s", misc_blk_device.c_str(),
88 strerror(errno));
89 return false;
90 }
91 if (!android::base::ReadFully(fd, p, size)) {
92 *err = android::base::StringPrintf("failed to read %s: %s", misc_blk_device.c_str(),
93 strerror(errno));
94 return false;
95 }
96 return true;
97 }
98
write_misc_partition(const void * p,size_t size,const std::string & misc_blk_device,size_t offset,std::string * err)99 static bool write_misc_partition(const void* p, size_t size, const std::string& misc_blk_device,
100 size_t offset, std::string* err) {
101 android::base::unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY));
102 if (fd == -1) {
103 *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(),
104 strerror(errno));
105 return false;
106 }
107 if (lseek(fd, static_cast<off_t>(offset), SEEK_SET) != static_cast<off_t>(offset)) {
108 *err = android::base::StringPrintf("failed to lseek %s: %s", misc_blk_device.c_str(),
109 strerror(errno));
110 return false;
111 }
112 if (!android::base::WriteFully(fd, p, size)) {
113 *err = android::base::StringPrintf("failed to write %s: %s", misc_blk_device.c_str(),
114 strerror(errno));
115 return false;
116 }
117 if (fsync(fd) == -1) {
118 *err = android::base::StringPrintf("failed to fsync %s: %s", misc_blk_device.c_str(),
119 strerror(errno));
120 return false;
121 }
122 return true;
123 }
124
get_bootloader_message_blk_device(std::string * err)125 std::string get_bootloader_message_blk_device(std::string* err) {
126 std::string misc_blk_device = get_misc_blk_device(err);
127 if (misc_blk_device.empty()) return "";
128 if (!wait_for_device(misc_blk_device, err)) return "";
129 return misc_blk_device;
130 }
131
read_bootloader_message_from(bootloader_message * boot,const std::string & misc_blk_device,std::string * err)132 bool read_bootloader_message_from(bootloader_message* boot, const std::string& misc_blk_device,
133 std::string* err) {
134 return read_misc_partition(boot, sizeof(*boot), misc_blk_device,
135 BOOTLOADER_MESSAGE_OFFSET_IN_MISC, err);
136 }
137
read_bootloader_message(bootloader_message * boot,std::string * err)138 bool read_bootloader_message(bootloader_message* boot, std::string* err) {
139 std::string misc_blk_device = get_misc_blk_device(err);
140 if (misc_blk_device.empty()) {
141 return false;
142 }
143 return read_bootloader_message_from(boot, misc_blk_device, err);
144 }
145
read_bootloader_control_from(bootloader_control * boot_ctrl,const std::string & misc_blk_device,std::string * err)146 bool read_bootloader_control_from(bootloader_control* boot_ctrl, const std::string& misc_blk_device,
147 std::string* err) {
148 return read_misc_partition(boot_ctrl, sizeof(bootloader_control), misc_blk_device,
149 kBootloaderControlOffset, err);
150 }
151
write_bootloader_message_to(const bootloader_message & boot,const std::string & misc_blk_device,std::string * err)152 bool write_bootloader_message_to(const bootloader_message& boot, const std::string& misc_blk_device,
153 std::string* err) {
154 return write_misc_partition(&boot, sizeof(boot), misc_blk_device,
155 BOOTLOADER_MESSAGE_OFFSET_IN_MISC, err);
156 }
157
write_bootloader_message(const bootloader_message & boot,std::string * err)158 bool write_bootloader_message(const bootloader_message& boot, std::string* err) {
159 std::string misc_blk_device = get_misc_blk_device(err);
160 if (misc_blk_device.empty()) {
161 return false;
162 }
163 return write_bootloader_message_to(boot, misc_blk_device, err);
164 }
165
write_bootloader_control_to(const bootloader_control * boot_ctrl,const std::string & misc_blk_device,std::string * err)166 bool write_bootloader_control_to(const bootloader_control* boot_ctrl, const std::string& misc_blk_device,
167 std::string* err) {
168 return write_misc_partition(boot_ctrl, sizeof(bootloader_control), misc_blk_device,
169 kBootloaderControlOffset, err);
170 }
171
clear_bootloader_message(std::string * err)172 bool clear_bootloader_message(std::string* err) {
173 bootloader_message boot = {};
174 return write_bootloader_message(boot, err);
175 }
176
write_bootloader_message(const std::vector<std::string> & options,std::string * err)177 bool write_bootloader_message(const std::vector<std::string>& options, std::string* err) {
178 bootloader_message boot = {};
179 update_bootloader_message_in_struct(&boot, options);
180
181 return write_bootloader_message(boot, err);
182 }
183
update_bootloader_message(const std::vector<std::string> & options,std::string * err)184 bool update_bootloader_message(const std::vector<std::string>& options, std::string* err) {
185 bootloader_message boot;
186 if (!read_bootloader_message(&boot, err)) {
187 return false;
188 }
189 update_bootloader_message_in_struct(&boot, options);
190
191 return write_bootloader_message(boot, err);
192 }
193
update_bootloader_message_in_struct(bootloader_message * boot,const std::vector<std::string> & options)194 bool update_bootloader_message_in_struct(bootloader_message* boot,
195 const std::vector<std::string>& options) {
196 if (!boot) return false;
197 // Replace the command & recovery fields.
198 memset(boot->command, 0, sizeof(boot->command));
199 memset(boot->recovery, 0, sizeof(boot->recovery));
200
201 strlcpy(boot->command, "boot-recovery", sizeof(boot->command));
202 strlcpy(boot->recovery, "recovery\n", sizeof(boot->recovery));
203 for (const auto& s : options) {
204 strlcat(boot->recovery, s.c_str(), sizeof(boot->recovery));
205 if (s.back() != '\n') {
206 strlcat(boot->recovery, "\n", sizeof(boot->recovery));
207 }
208 }
209 return true;
210 }
211
write_reboot_bootloader(std::string * err)212 bool write_reboot_bootloader(std::string* err) {
213 bootloader_message boot;
214 if (!read_bootloader_message(&boot, err)) {
215 return false;
216 }
217 if (boot.command[0] != '\0') {
218 *err = "Bootloader command pending.";
219 return false;
220 }
221 strlcpy(boot.command, "bootonce-bootloader", sizeof(boot.command));
222 return write_bootloader_message(boot, err);
223 }
224
read_wipe_package(std::string * package_data,size_t size,std::string * err)225 bool read_wipe_package(std::string* package_data, size_t size, std::string* err) {
226 std::string misc_blk_device = get_misc_blk_device(err);
227 if (misc_blk_device.empty()) {
228 return false;
229 }
230 package_data->resize(size);
231 return read_misc_partition(&(*package_data)[0], size, misc_blk_device,
232 WIPE_PACKAGE_OFFSET_IN_MISC, err);
233 }
234
write_wipe_package(const std::string & package_data,std::string * err)235 bool write_wipe_package(const std::string& package_data, std::string* err) {
236 std::string misc_blk_device = get_misc_blk_device(err);
237 if (misc_blk_device.empty()) {
238 return false;
239 }
240 return write_misc_partition(package_data.data(), package_data.size(), misc_blk_device,
241 WIPE_PACKAGE_OFFSET_IN_MISC, err);
242 }
243
write_reboot_bootloader(void)244 extern "C" bool write_reboot_bootloader(void) {
245 std::string err;
246 return write_reboot_bootloader(&err);
247 }
248
write_bootloader_message(const char * options)249 extern "C" bool write_bootloader_message(const char* options) {
250 std::string err;
251 return write_bootloader_message({options}, &err);
252 }
253