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