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 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. 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 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 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 } 119 120 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 } 126 127 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 } 132 133 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 } 140 141 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 } 146 147 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 } 154 155 bool clear_bootloader_message(std::string* err) { 156 bootloader_message boot = {}; 157 return write_bootloader_message(boot, err); 158 } 159 160 bool write_bootloader_message(const std::vector<std::string>& options, std::string* err) { 161 bootloader_message boot = {}; 162 update_bootloader_message_in_struct(&boot, options); 163 164 return write_bootloader_message(boot, err); 165 } 166 167 bool update_bootloader_message(const std::vector<std::string>& options, std::string* err) { 168 bootloader_message boot; 169 if (!read_bootloader_message(&boot, err)) { 170 return false; 171 } 172 update_bootloader_message_in_struct(&boot, options); 173 174 return write_bootloader_message(boot, err); 175 } 176 177 bool update_bootloader_message_in_struct(bootloader_message* boot, 178 const std::vector<std::string>& options) { 179 if (!boot) return false; 180 // Replace the command & recovery fields. 181 memset(boot->command, 0, sizeof(boot->command)); 182 memset(boot->recovery, 0, sizeof(boot->recovery)); 183 184 strlcpy(boot->command, "boot-recovery", sizeof(boot->command)); 185 strlcpy(boot->recovery, "recovery\n", sizeof(boot->recovery)); 186 for (const auto& s : options) { 187 strlcat(boot->recovery, s.c_str(), sizeof(boot->recovery)); 188 if (s.back() != '\n') { 189 strlcat(boot->recovery, "\n", sizeof(boot->recovery)); 190 } 191 } 192 return true; 193 } 194 195 bool write_reboot_bootloader(std::string* err) { 196 bootloader_message boot; 197 if (!read_bootloader_message(&boot, err)) { 198 return false; 199 } 200 if (boot.command[0] != '\0') { 201 *err = "Bootloader command pending."; 202 return false; 203 } 204 strlcpy(boot.command, "bootonce-bootloader", sizeof(boot.command)); 205 return write_bootloader_message(boot, err); 206 } 207 208 bool read_wipe_package(std::string* package_data, size_t size, std::string* err) { 209 std::string misc_blk_device = get_misc_blk_device(err); 210 if (misc_blk_device.empty()) { 211 return false; 212 } 213 package_data->resize(size); 214 return read_misc_partition(&(*package_data)[0], size, misc_blk_device, 215 WIPE_PACKAGE_OFFSET_IN_MISC, err); 216 } 217 218 bool write_wipe_package(const std::string& package_data, std::string* err) { 219 std::string misc_blk_device = get_misc_blk_device(err); 220 if (misc_blk_device.empty()) { 221 return false; 222 } 223 return write_misc_partition(package_data.data(), package_data.size(), misc_blk_device, 224 WIPE_PACKAGE_OFFSET_IN_MISC, err); 225 } 226 227 extern "C" bool write_reboot_bootloader(void) { 228 std::string err; 229 return write_reboot_bootloader(&err); 230 } 231 232 extern "C" bool write_bootloader_message(const char* options) { 233 std::string err; 234 return write_bootloader_message({options}, &err); 235 } 236
