model/Disk.cpp - SHIFTPHONES/android_system_vold - Gitiles

 /*
  * Copyright (C) 2015 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "Disk.h"
 #include "FsCrypt.h"
 #include "KeyUtil.h"
 #include "PrivateVolume.h"
 #include "PublicVolume.h"
 #include "Utils.h"
 #include "VolumeBase.h"
 #include "VolumeManager.h"

 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <fscrypt/fscrypt.h>

 #include "cryptfs.h"

 #include <fcntl.h>
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/sysmacros.h>
 #include <sys/types.h>
 #include <vector>

 using android::base::ReadFileToString;
 using android::base::StringPrintf;
 using android::base::WriteStringToFile;

 namespace android {
 namespace vold {

 static const char* kSgdiskPath = "/system/bin/sgdisk";
 static const char* kSgdiskToken = " \t\n";

 static const char* kSysfsLoopMaxMinors = "/sys/module/loop/parameters/max_part";
 static const char* kSysfsMmcMaxMinorsDeprecated = "/sys/module/mmcblk/parameters/perdev_minors";
 static const char* kSysfsMmcMaxMinors = "/sys/module/mmc_block/parameters/perdev_minors";

 static const unsigned int kMajorBlockLoop = 7;
 static const unsigned int kMajorBlockScsiA = 8;
 static const unsigned int kMajorBlockScsiB = 65;
 static const unsigned int kMajorBlockScsiC = 66;
 static const unsigned int kMajorBlockScsiD = 67;
 static const unsigned int kMajorBlockScsiE = 68;
 static const unsigned int kMajorBlockScsiF = 69;
 static const unsigned int kMajorBlockScsiG = 70;
 static const unsigned int kMajorBlockScsiH = 71;
 static const unsigned int kMajorBlockScsiI = 128;
 static const unsigned int kMajorBlockScsiJ = 129;
 static const unsigned int kMajorBlockScsiK = 130;
 static const unsigned int kMajorBlockScsiL = 131;
 static const unsigned int kMajorBlockScsiM = 132;
 static const unsigned int kMajorBlockScsiN = 133;
 static const unsigned int kMajorBlockScsiO = 134;
 static const unsigned int kMajorBlockScsiP = 135;
 static const unsigned int kMajorBlockMmc = 179;
 static const unsigned int kMajorBlockExperimentalMin = 240;
 static const unsigned int kMajorBlockExperimentalMax = 254;
 static const unsigned int kMajorBlockDynamicMin = 234;
 static const unsigned int kMajorBlockDynamicMax = 512;

 static const char* kGptBasicData = "EBD0A0A2-B9E5-4433-87C0-68B6B72699C7";
 static const char* kGptAndroidMeta = "19A710A2-B3CA-11E4-B026-10604B889DCF";
 static const char* kGptAndroidExpand = "193D1EA4-B3CA-11E4-B075-10604B889DCF";

 enum class Table {
     kUnknown,
     kMbr,
     kGpt,
 };

 static bool isVirtioBlkDevice(unsigned int major) {
     /*
      * The new emulator's "ranchu" virtual board no longer includes a goldfish
      * MMC-based SD card device; instead, it emulates SD cards with virtio-blk,
      * which has been supported by upstream kernel and QEMU for quite a while.
      * Unfortunately, the virtio-blk block device driver does not use a fixed
      * major number, but relies on the kernel to assign one from a specific
      * range of block majors, which are allocated for "LOCAL/EXPERIMENAL USE"
      * per Documentation/devices.txt. This is true even for the latest Linux
      * kernel (4.4; see init() in drivers/block/virtio_blk.c).
      *
      * This makes it difficult for vold to detect a virtio-blk based SD card.
      * The current solution checks two conditions (both must be met):
      *
      *  a) If the running environment is the emulator;
      *  b) If the major number is an experimental block device major number (for
      *     x86/x86_64 3.10 ranchu kernels, virtio-blk always gets major number
      *     253, but it is safer to match the range than just one value).
      *
      * Other conditions could be used, too, e.g. the hardware name should be
      * "ranchu", the device's sysfs path should end with "/block/vd[d-z]", etc.
      * But just having a) and b) is enough for now.
      */
     return IsRunningInEmulator() && major >= kMajorBlockExperimentalMin &&
            major <= kMajorBlockExperimentalMax;
 }

 static bool isNvmeBlkDevice(unsigned int major, const std::string& sysPath) {
     return sysPath.find("nvme") != std::string::npos && major >= kMajorBlockDynamicMin &&
            major <= kMajorBlockDynamicMax;
 }

 Disk::Disk(const std::string& eventPath, dev_t device, const std::string& nickname, int flags)
     : mDevice(device),
       mSize(-1),
       mNickname(nickname),
       mFlags(flags),
       mCreated(false),
       mJustPartitioned(false) {
     mId = StringPrintf("disk:%u,%u", major(device), minor(device));
     mEventPath = eventPath;
     mSysPath = StringPrintf("/sys/%s", eventPath.c_str());
     mDevPath = StringPrintf("/dev/block/vold/%s", mId.c_str());
     CreateDeviceNode(mDevPath, mDevice);
 }

 Disk::~Disk() {
     CHECK(!mCreated);
     DestroyDeviceNode(mDevPath);
 }

 std::shared_ptr<VolumeBase> Disk::findVolume(const std::string& id) {
     for (auto vol : mVolumes) {
         if (vol->getId() == id) {
             return vol;
         }
         auto stackedVol = vol->findVolume(id);
         if (stackedVol != nullptr) {
             return stackedVol;
         }
     }
     return nullptr;
 }

 void Disk::listVolumes(VolumeBase::Type type, std::list<std::string>& list) const {
     for (const auto& vol : mVolumes) {
         if (vol->getType() == type) {
             list.push_back(vol->getId());
         }
         // TODO: consider looking at stacked volumes
     }
 }

 std::vector<std::shared_ptr<VolumeBase>> Disk::getVolumes() const {
     std::vector<std::shared_ptr<VolumeBase>> vols;
     for (const auto& vol : mVolumes) {
         vols.push_back(vol);
         auto stackedVolumes = vol->getVolumes();
         vols.insert(vols.end(), stackedVolumes.begin(), stackedVolumes.end());
     }

     return vols;
 }

 status_t Disk::create() {
     CHECK(!mCreated);
     mCreated = true;

     auto listener = VolumeManager::Instance()->getListener();
     if (listener) listener->onDiskCreated(getId(), mFlags);

     if (isStub()) {
         createStubVolume();
         return OK;
     }
     readMetadata();
     readPartitions();
     return OK;
 }

 status_t Disk::destroy() {
     CHECK(mCreated);
     destroyAllVolumes();
     mCreated = false;

     auto listener = VolumeManager::Instance()->getListener();
     if (listener) listener->onDiskDestroyed(getId());

     return OK;
 }

 void Disk::createPublicVolume(dev_t device) {
     auto vol = std::shared_ptr<VolumeBase>(new PublicVolume(device));
     if (mJustPartitioned) {
         LOG(DEBUG) << "Device just partitioned; silently formatting";
         vol->setSilent(true);
         vol->create();
         vol->format("auto");
         vol->destroy();
         vol->setSilent(false);
     }

     mVolumes.push_back(vol);
     vol->setDiskId(getId());
     vol->create();
 }

 void Disk::createPrivateVolume(dev_t device, const std::string& partGuid) {
     std::string normalizedGuid;
     if (NormalizeHex(partGuid, normalizedGuid)) {
         LOG(WARNING) << "Invalid GUID " << partGuid;
         return;
     }

     std::string keyRaw;
     if (!ReadFileToString(BuildKeyPath(normalizedGuid), &keyRaw)) {
         PLOG(ERROR) << "Failed to load key for GUID " << normalizedGuid;
         return;
     }

     LOG(DEBUG) << "Found key for GUID " << normalizedGuid;

     auto keyBuffer = KeyBuffer(keyRaw.begin(), keyRaw.end());
     auto vol = std::shared_ptr<VolumeBase>(new PrivateVolume(device, keyBuffer));
     if (mJustPartitioned) {
         LOG(DEBUG) << "Device just partitioned; silently formatting";
         vol->setSilent(true);
         vol->create();
         vol->format("auto");
         vol->destroy();
         vol->setSilent(false);
     }

     mVolumes.push_back(vol);
     vol->setDiskId(getId());
     vol->setPartGuid(partGuid);
     vol->create();
 }

 void Disk::createStubVolume() {
     CHECK(mVolumes.size() == 1);
     auto listener = VolumeManager::Instance()->getListener();
     if (listener) listener->onDiskMetadataChanged(getId(), mSize, mLabel, mSysPath);
     if (listener) listener->onDiskScanned(getId());
     mVolumes[0]->setDiskId(getId());
     mVolumes[0]->create();
 }

 void Disk::destroyAllVolumes() {
     for (const auto& vol : mVolumes) {
         vol->destroy();
     }
     mVolumes.clear();
 }

 status_t Disk::readMetadata() {
     mSize = -1;
     mLabel.clear();

     if (GetBlockDevSize(mDevPath, &mSize) != OK) {
         mSize = -1;
     }

     unsigned int majorId = major(mDevice);
     switch (majorId) {
         case kMajorBlockLoop: {
             mLabel = "Virtual";
             break;
         }
         // clang-format off
         case kMajorBlockScsiA: case kMajorBlockScsiB: case kMajorBlockScsiC:
         case kMajorBlockScsiD: case kMajorBlockScsiE: case kMajorBlockScsiF:
         case kMajorBlockScsiG: case kMajorBlockScsiH: case kMajorBlockScsiI:
         case kMajorBlockScsiJ: case kMajorBlockScsiK: case kMajorBlockScsiL:
         case kMajorBlockScsiM: case kMajorBlockScsiN: case kMajorBlockScsiO:
         case kMajorBlockScsiP: {
             // clang-format on
             std::string path(mSysPath + "/device/vendor");
             std::string tmp;
             if (!ReadFileToString(path, &tmp)) {
                 PLOG(WARNING) << "Failed to read vendor from " << path;
                 return -errno;
             }
             tmp = android::base::Trim(tmp);
             mLabel = tmp;
             break;
         }
         case kMajorBlockMmc: {
             std::string path(mSysPath + "/device/manfid");
             std::string tmp;
             if (!ReadFileToString(path, &tmp)) {
                 PLOG(WARNING) << "Failed to read manufacturer from " << path;
                 return -errno;
             }
             tmp = android::base::Trim(tmp);
             int64_t manfid;
             if (!android::base::ParseInt(tmp, &manfid)) {
                 PLOG(WARNING) << "Failed to parse manufacturer " << tmp;
                 return -EINVAL;
             }
             // Our goal here is to give the user a meaningful label, ideally
             // matching whatever is silk-screened on the card.  To reduce
             // user confusion, this list doesn't contain white-label manfid.
             switch (manfid) {
                 // clang-format off
                 case 0x000003: mLabel = "SanDisk"; break;
                 case 0x00001b: mLabel = "Samsung"; break;
                 case 0x000028: mLabel = "Lexar"; break;
                 case 0x000074: mLabel = "Transcend"; break;
                     // clang-format on
             }
             break;
         }
         default: {
             if (isVirtioBlkDevice(majorId)) {
                 LOG(DEBUG) << "Recognized experimental block major ID " << majorId
                            << " as virtio-blk (emulator's virtual SD card device)";
                 mLabel = "Virtual";
                 break;
             }
             if (isNvmeBlkDevice(majorId, mSysPath)) {
                 std::string path(mSysPath + "/device/model");
                 std::string tmp;
                 if (!ReadFileToString(path, &tmp)) {
                     PLOG(WARNING) << "Failed to read vendor from " << path;
                     return -errno;
                 }
                 mLabel = tmp;
                 break;
             }
             LOG(WARNING) << "Unsupported block major type " << majorId;
             return -ENOTSUP;
         }
     }

     auto listener = VolumeManager::Instance()->getListener();
     if (listener) listener->onDiskMetadataChanged(getId(), mSize, mLabel, mSysPath);

     return OK;
 }

 status_t Disk::readPartitions() {
     int maxMinors = getMaxMinors();
     if (maxMinors < 0) {
         return -ENOTSUP;
     }

     destroyAllVolumes();

     // Parse partition table

     std::vector<std::string> cmd;
     cmd.push_back(kSgdiskPath);
     cmd.push_back("--android-dump");
     cmd.push_back(mDevPath);

     std::vector<std::string> output;
     status_t res = ForkExecvp(cmd, &output);
     if (res != OK) {
         LOG(WARNING) << "sgdisk failed to scan " << mDevPath;

         auto listener = VolumeManager::Instance()->getListener();
         if (listener) listener->onDiskScanned(getId());

         mJustPartitioned = false;
         return res;
     }

     Table table = Table::kUnknown;
     bool foundParts = false;
     for (const auto& line : output) {
         auto split = android::base::Split(line, kSgdiskToken);
         auto it = split.begin();
         if (it == split.end()) continue;

         if (*it == "DISK") {
             if (++it == split.end()) continue;
             if (*it == "mbr") {
                 table = Table::kMbr;
             } else if (*it == "gpt") {
                 table = Table::kGpt;
             } else {
                 LOG(WARNING) << "Invalid partition table " << *it;
                 continue;
             }
         } else if (*it == "PART") {
             foundParts = true;

             if (++it == split.end()) continue;
             int i = 0;
             if (!android::base::ParseInt(*it, &i, 1, maxMinors)) {
                 LOG(WARNING) << "Invalid partition number " << *it;
                 continue;
             }
             dev_t partDevice = makedev(major(mDevice), minor(mDevice) + i);

             if (table == Table::kMbr) {
                 if (++it == split.end()) continue;
                 int type = 0;
                 if (!android::base::ParseInt("0x" + *it, &type)) {
                     LOG(WARNING) << "Invalid partition type " << *it;
                     continue;
                 }

                 switch (type) {
                     case 0x06:  // FAT16
                     case 0x07:  // HPFS/NTFS/exFAT
                     case 0x0b:  // W95 FAT32 (LBA)
                     case 0x0c:  // W95 FAT32 (LBA)
                     case 0x0e:  // W95 FAT16 (LBA)
                         createPublicVolume(partDevice);
                         break;
                 }
             } else if (table == Table::kGpt) {
                 if (++it == split.end()) continue;
                 auto typeGuid = *it;
                 if (++it == split.end()) continue;
                 auto partGuid = *it;

                 if (android::base::EqualsIgnoreCase(typeGuid, kGptBasicData)) {
                     createPublicVolume(partDevice);
                 } else if (android::base::EqualsIgnoreCase(typeGuid, kGptAndroidExpand)) {
                     createPrivateVolume(partDevice, partGuid);
                 }
             }
         }
     }

     // Ugly last ditch effort, treat entire disk as partition
     if (table == Table::kUnknown || !foundParts) {
         LOG(WARNING) << mId << " has unknown partition table; trying entire device";

         std::string fsType;
         std::string unused;
         if (ReadMetadataUntrusted(mDevPath, &fsType, &unused, &unused) == OK) {
             createPublicVolume(mDevice);
         } else {
             LOG(WARNING) << mId << " failed to identify, giving up";
         }
     }

     auto listener = VolumeManager::Instance()->getListener();
     if (listener) listener->onDiskScanned(getId());

     mJustPartitioned = false;
     return OK;
 }

 void Disk::initializePartition(std::shared_ptr<StubVolume> vol) {
     CHECK(isStub());
     CHECK(mVolumes.empty());
     mVolumes.push_back(vol);
 }

 status_t Disk::unmountAll() {
     for (const auto& vol : mVolumes) {
         vol->unmount();
     }
     return OK;
 }

 status_t Disk::partitionPublic() {
     int res;

     destroyAllVolumes();
     mJustPartitioned = true;

     // First nuke any existing partition table
     std::vector<std::string> cmd;
     cmd.push_back(kSgdiskPath);
     cmd.push_back("--zap-all");
     cmd.push_back(mDevPath);

     // Zap sometimes returns an error when it actually succeeded, so
     // just log as warning and keep rolling forward.
     if ((res = ForkExecvp(cmd)) != 0) {
         LOG(WARNING) << "Failed to zap; status " << res;
     }

     // Now let's build the new MBR table. We heavily rely on sgdisk to
     // force optimal alignment on the created partitions.
     cmd.clear();
     cmd.push_back(kSgdiskPath);
     cmd.push_back("--new=0:0:-0");
     cmd.push_back("--typecode=0:0c00");
     cmd.push_back("--gpttombr=1");
     cmd.push_back(mDevPath);

     if ((res = ForkExecvp(cmd)) != 0) {
         LOG(ERROR) << "Failed to partition; status " << res;
         return res;
     }

     return OK;
 }

 status_t Disk::partitionPrivate() {
     return partitionMixed(0);
 }

 status_t Disk::partitionMixed(int8_t ratio) {
     int res;

     destroyAllVolumes();
     mJustPartitioned = true;

     // First nuke any existing partition table
     std::vector<std::string> cmd;
     cmd.push_back(kSgdiskPath);
     cmd.push_back("--zap-all");
     cmd.push_back(mDevPath);

     // Zap sometimes returns an error when it actually succeeded, so
     // just log as warning and keep rolling forward.
     if ((res = ForkExecvp(cmd)) != 0) {
         LOG(WARNING) << "Failed to zap; status " << res;
     }

     // We've had some success above, so generate both the private partition
     // GUID and encryption key and persist them.
     std::string partGuidRaw;
     if (GenerateRandomUuid(partGuidRaw) != OK) {
         LOG(ERROR) << "Failed to generate GUID";
         return -EIO;
     }

     KeyBuffer key;
     if (!generateStorageKey(cryptfs_get_keygen(), &key)) {
         LOG(ERROR) << "Failed to generate key";
         return -EIO;
     }
     std::string keyRaw(key.begin(), key.end());

     std::string partGuid;
     StrToHex(partGuidRaw, partGuid);

     if (!WriteStringToFile(keyRaw, BuildKeyPath(partGuid))) {
         LOG(ERROR) << "Failed to persist key";
         return -EIO;
     } else {
         LOG(DEBUG) << "Persisted key for GUID " << partGuid;
     }

     // Now let's build the new GPT table. We heavily rely on sgdisk to
     // force optimal alignment on the created partitions.
     cmd.clear();
     cmd.push_back(kSgdiskPath);

     // If requested, create a public partition first. Mixed-mode partitioning
     // like this is an experimental feature.
     if (ratio > 0) {
         if (ratio < 10 || ratio > 90) {
             LOG(ERROR) << "Mixed partition ratio must be between 10-90%";
             return -EINVAL;
         }

         uint64_t splitMb = ((mSize / 100) * ratio) / 1024 / 1024;
         cmd.push_back(StringPrintf("--new=0:0:+%" PRId64 "M", splitMb));
         cmd.push_back(StringPrintf("--typecode=0:%s", kGptBasicData));
         cmd.push_back("--change-name=0:shared");
     }

     // Define a metadata partition which is designed for future use; there
     // should only be one of these per physical device, even if there are
     // multiple private volumes.
     cmd.push_back("--new=0:0:+16M");
     cmd.push_back(StringPrintf("--typecode=0:%s", kGptAndroidMeta));
     cmd.push_back("--change-name=0:android_meta");

     // Define a single private partition filling the rest of disk.
     cmd.push_back("--new=0:0:-0");
     cmd.push_back(StringPrintf("--typecode=0:%s", kGptAndroidExpand));
     cmd.push_back(StringPrintf("--partition-guid=0:%s", partGuid.c_str()));
     cmd.push_back("--change-name=0:android_expand");

     cmd.push_back(mDevPath);

     if ((res = ForkExecvp(cmd)) != 0) {
         LOG(ERROR) << "Failed to partition; status " << res;
         return res;
     }

     return OK;
 }

 int Disk::getMaxMinors() {
     // Figure out maximum partition devices supported
     unsigned int majorId = major(mDevice);
     switch (majorId) {
         case kMajorBlockLoop: {
             std::string tmp;
             if (!ReadFileToString(kSysfsLoopMaxMinors, &tmp)) {
                 LOG(ERROR) << "Failed to read max minors";
                 return -errno;
             }
             return std::stoi(tmp);
         }
         // clang-format off
         case kMajorBlockScsiA: case kMajorBlockScsiB: case kMajorBlockScsiC:
         case kMajorBlockScsiD: case kMajorBlockScsiE: case kMajorBlockScsiF:
         case kMajorBlockScsiG: case kMajorBlockScsiH: case kMajorBlockScsiI:
         case kMajorBlockScsiJ: case kMajorBlockScsiK: case kMajorBlockScsiL:
         case kMajorBlockScsiM: case kMajorBlockScsiN: case kMajorBlockScsiO:
         case kMajorBlockScsiP: {
             // clang-format on
             // Per Documentation/devices.txt this is static
             return 15;
         }
         case kMajorBlockMmc: {
             // Per Documentation/devices.txt this is dynamic
             std::string tmp;
             if (!ReadFileToString(kSysfsMmcMaxMinors, &tmp) &&
                 !ReadFileToString(kSysfsMmcMaxMinorsDeprecated, &tmp)) {
                 LOG(ERROR) << "Failed to read max minors";
                 return -errno;
             }
             return std::stoi(tmp);
         }
         default: {
             if (isVirtioBlkDevice(majorId)) {
                 // drivers/block/virtio_blk.c has "#define PART_BITS 4", so max is
                 // 2^4 - 1 = 15
                 return 15;
             }
             if (isNvmeBlkDevice(majorId, mSysPath)) {
                 // despite kernel nvme driver supports up to 1M minors,
                 //     #define NVME_MINORS (1U << MINORBITS)
                 // sgdisk can not support more than 127 partitions, due to
                 //     #define MAX_MBR_PARTS 128
                 return 127;
             }
         }
     }

     LOG(ERROR) << "Unsupported block major type " << majorId;
     return -ENOTSUP;
 }

 }  // namespace vold
 }  // namespace android
	/*
	* Copyright (C) 2015 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "Disk.h"
	#include "FsCrypt.h"
	#include "KeyUtil.h"
	#include "PrivateVolume.h"
	#include "PublicVolume.h"
	#include "Utils.h"
	#include "VolumeBase.h"
	#include "VolumeManager.h"

	#include <android-base/file.h>
	#include <android-base/logging.h>
	#include <android-base/parseint.h>
	#include <android-base/properties.h>
	#include <android-base/stringprintf.h>
	#include <android-base/strings.h>
	#include <fscrypt/fscrypt.h>

	#include "cryptfs.h"

	#include <fcntl.h>
	#include <inttypes.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/mount.h>
	#include <sys/stat.h>
	#include <sys/sysmacros.h>
	#include <sys/types.h>
	#include <vector>

	using android::base::ReadFileToString;
	using android::base::StringPrintf;
	using android::base::WriteStringToFile;

	namespace android {
	namespace vold {

	static const char* kSgdiskPath = "/system/bin/sgdisk";
	static const char* kSgdiskToken = " \t\n";

	static const char* kSysfsLoopMaxMinors = "/sys/module/loop/parameters/max_part";
	static const char* kSysfsMmcMaxMinorsDeprecated = "/sys/module/mmcblk/parameters/perdev_minors";
	static const char* kSysfsMmcMaxMinors = "/sys/module/mmc_block/parameters/perdev_minors";

	static const unsigned int kMajorBlockLoop = 7;
	static const unsigned int kMajorBlockScsiA = 8;
	static const unsigned int kMajorBlockScsiB = 65;
	static const unsigned int kMajorBlockScsiC = 66;
	static const unsigned int kMajorBlockScsiD = 67;
	static const unsigned int kMajorBlockScsiE = 68;
	static const unsigned int kMajorBlockScsiF = 69;
	static const unsigned int kMajorBlockScsiG = 70;
	static const unsigned int kMajorBlockScsiH = 71;
	static const unsigned int kMajorBlockScsiI = 128;
	static const unsigned int kMajorBlockScsiJ = 129;
	static const unsigned int kMajorBlockScsiK = 130;
	static const unsigned int kMajorBlockScsiL = 131;
	static const unsigned int kMajorBlockScsiM = 132;
	static const unsigned int kMajorBlockScsiN = 133;
	static const unsigned int kMajorBlockScsiO = 134;
	static const unsigned int kMajorBlockScsiP = 135;
	static const unsigned int kMajorBlockMmc = 179;
	static const unsigned int kMajorBlockExperimentalMin = 240;
	static const unsigned int kMajorBlockExperimentalMax = 254;
	static const unsigned int kMajorBlockDynamicMin = 234;
	static const unsigned int kMajorBlockDynamicMax = 512;

	static const char* kGptBasicData = "EBD0A0A2-B9E5-4433-87C0-68B6B72699C7";
	static const char* kGptAndroidMeta = "19A710A2-B3CA-11E4-B026-10604B889DCF";
	static const char* kGptAndroidExpand = "193D1EA4-B3CA-11E4-B075-10604B889DCF";

	enum class Table {
	kUnknown,
	kMbr,
	kGpt,
	};

	static bool isVirtioBlkDevice(unsigned int major) {
	/*
	* The new emulator's "ranchu" virtual board no longer includes a goldfish
	* MMC-based SD card device; instead, it emulates SD cards with virtio-blk,
	* which has been supported by upstream kernel and QEMU for quite a while.
	* Unfortunately, the virtio-blk block device driver does not use a fixed
	* major number, but relies on the kernel to assign one from a specific
	* range of block majors, which are allocated for "LOCAL/EXPERIMENAL USE"
	* per Documentation/devices.txt. This is true even for the latest Linux
	* kernel (4.4; see init() in drivers/block/virtio_blk.c).
	*
	* This makes it difficult for vold to detect a virtio-blk based SD card.
	* The current solution checks two conditions (both must be met):
	*
	* a) If the running environment is the emulator;
	* b) If the major number is an experimental block device major number (for
	* x86/x86_64 3.10 ranchu kernels, virtio-blk always gets major number
	* 253, but it is safer to match the range than just one value).
	*
	* Other conditions could be used, too, e.g. the hardware name should be
	* "ranchu", the device's sysfs path should end with "/block/vd[d-z]", etc.
	* But just having a) and b) is enough for now.
	*/
	return IsRunningInEmulator() && major >= kMajorBlockExperimentalMin &&
	major <= kMajorBlockExperimentalMax;
	}

	static bool isNvmeBlkDevice(unsigned int major, const std::string& sysPath) {
	return sysPath.find("nvme") != std::string::npos && major >= kMajorBlockDynamicMin &&
	major <= kMajorBlockDynamicMax;
	}

	Disk::Disk(const std::string& eventPath, dev_t device, const std::string& nickname, int flags)
	: mDevice(device),
	mSize(-1),
	mNickname(nickname),
	mFlags(flags),
	mCreated(false),
	mJustPartitioned(false) {
	mId = StringPrintf("disk:%u,%u", major(device), minor(device));
	mEventPath = eventPath;
	mSysPath = StringPrintf("/sys/%s", eventPath.c_str());
	mDevPath = StringPrintf("/dev/block/vold/%s", mId.c_str());
	CreateDeviceNode(mDevPath, mDevice);
	}

	Disk::~Disk() {
	CHECK(!mCreated);
	DestroyDeviceNode(mDevPath);
	}

	std::shared_ptr<VolumeBase> Disk::findVolume(const std::string& id) {
	for (auto vol : mVolumes) {
	if (vol->getId() == id) {
	return vol;
	}
	auto stackedVol = vol->findVolume(id);
	if (stackedVol != nullptr) {
	return stackedVol;
	}
	}
	return nullptr;
	}

	void Disk::listVolumes(VolumeBase::Type type, std::list<std::string>& list) const {
	for (const auto& vol : mVolumes) {
	if (vol->getType() == type) {
	list.push_back(vol->getId());
	}
	// TODO: consider looking at stacked volumes
	}
	}

	std::vector<std::shared_ptr<VolumeBase>> Disk::getVolumes() const {
	std::vector<std::shared_ptr<VolumeBase>> vols;
	for (const auto& vol : mVolumes) {
	vols.push_back(vol);
	auto stackedVolumes = vol->getVolumes();
	vols.insert(vols.end(), stackedVolumes.begin(), stackedVolumes.end());
	}

	return vols;
	}

	status_t Disk::create() {
	CHECK(!mCreated);
	mCreated = true;

	auto listener = VolumeManager::Instance()->getListener();
	if (listener) listener->onDiskCreated(getId(), mFlags);

	if (isStub()) {
	createStubVolume();
	return OK;
	}
	readMetadata();
	readPartitions();
	return OK;
	}

	status_t Disk::destroy() {
	CHECK(mCreated);
	destroyAllVolumes();
	mCreated = false;

	auto listener = VolumeManager::Instance()->getListener();
	if (listener) listener->onDiskDestroyed(getId());

	return OK;
	}

	void Disk::createPublicVolume(dev_t device) {
	auto vol = std::shared_ptr<VolumeBase>(new PublicVolume(device));
	if (mJustPartitioned) {
	LOG(DEBUG) << "Device just partitioned; silently formatting";
	vol->setSilent(true);
	vol->create();
	vol->format("auto");
	vol->destroy();
	vol->setSilent(false);
	}

	mVolumes.push_back(vol);
	vol->setDiskId(getId());
	vol->create();
	}

	void Disk::createPrivateVolume(dev_t device, const std::string& partGuid) {
	std::string normalizedGuid;
	if (NormalizeHex(partGuid, normalizedGuid)) {
	LOG(WARNING) << "Invalid GUID " << partGuid;
	return;
	}

	std::string keyRaw;
	if (!ReadFileToString(BuildKeyPath(normalizedGuid), &keyRaw)) {
	PLOG(ERROR) << "Failed to load key for GUID " << normalizedGuid;
	return;
	}

	LOG(DEBUG) << "Found key for GUID " << normalizedGuid;

	auto keyBuffer = KeyBuffer(keyRaw.begin(), keyRaw.end());
	auto vol = std::shared_ptr<VolumeBase>(new PrivateVolume(device, keyBuffer));
	if (mJustPartitioned) {
	LOG(DEBUG) << "Device just partitioned; silently formatting";
	vol->setSilent(true);
	vol->create();
	vol->format("auto");
	vol->destroy();
	vol->setSilent(false);
	}

	mVolumes.push_back(vol);
	vol->setDiskId(getId());
	vol->setPartGuid(partGuid);
	vol->create();
	}

	void Disk::createStubVolume() {
	CHECK(mVolumes.size() == 1);
	auto listener = VolumeManager::Instance()->getListener();
	if (listener) listener->onDiskMetadataChanged(getId(), mSize, mLabel, mSysPath);
	if (listener) listener->onDiskScanned(getId());
	mVolumes[0]->setDiskId(getId());
	mVolumes[0]->create();
	}

	void Disk::destroyAllVolumes() {
	for (const auto& vol : mVolumes) {
	vol->destroy();
	}
	mVolumes.clear();
	}

	status_t Disk::readMetadata() {
	mSize = -1;
	mLabel.clear();

	if (GetBlockDevSize(mDevPath, &mSize) != OK) {
	mSize = -1;
	}

	unsigned int majorId = major(mDevice);
	switch (majorId) {
	case kMajorBlockLoop: {
	mLabel = "Virtual";
	break;
	}
	// clang-format off
	case kMajorBlockScsiA: case kMajorBlockScsiB: case kMajorBlockScsiC:
	case kMajorBlockScsiD: case kMajorBlockScsiE: case kMajorBlockScsiF:
	case kMajorBlockScsiG: case kMajorBlockScsiH: case kMajorBlockScsiI:
	case kMajorBlockScsiJ: case kMajorBlockScsiK: case kMajorBlockScsiL:
	case kMajorBlockScsiM: case kMajorBlockScsiN: case kMajorBlockScsiO:
	case kMajorBlockScsiP: {
	// clang-format on
	std::string path(mSysPath + "/device/vendor");
	std::string tmp;
	if (!ReadFileToString(path, &tmp)) {
	PLOG(WARNING) << "Failed to read vendor from " << path;
	return -errno;
	}
	tmp = android::base::Trim(tmp);
	mLabel = tmp;
	break;
	}
	case kMajorBlockMmc: {
	std::string path(mSysPath + "/device/manfid");
	std::string tmp;
	if (!ReadFileToString(path, &tmp)) {
	PLOG(WARNING) << "Failed to read manufacturer from " << path;
	return -errno;
	}
	tmp = android::base::Trim(tmp);
	int64_t manfid;
	if (!android::base::ParseInt(tmp, &manfid)) {
	PLOG(WARNING) << "Failed to parse manufacturer " << tmp;
	return -EINVAL;
	}
	// Our goal here is to give the user a meaningful label, ideally
	// matching whatever is silk-screened on the card. To reduce
	// user confusion, this list doesn't contain white-label manfid.
	switch (manfid) {
	// clang-format off
	case 0x000003: mLabel = "SanDisk"; break;
	case 0x00001b: mLabel = "Samsung"; break;
	case 0x000028: mLabel = "Lexar"; break;
	case 0x000074: mLabel = "Transcend"; break;
	// clang-format on
	}
	break;
	}
	default: {
	if (isVirtioBlkDevice(majorId)) {
	LOG(DEBUG) << "Recognized experimental block major ID " << majorId
	<< " as virtio-blk (emulator's virtual SD card device)";
	mLabel = "Virtual";
	break;
	}
	if (isNvmeBlkDevice(majorId, mSysPath)) {
	std::string path(mSysPath + "/device/model");
	std::string tmp;
	if (!ReadFileToString(path, &tmp)) {
	PLOG(WARNING) << "Failed to read vendor from " << path;
	return -errno;
	}
	mLabel = tmp;
	break;
	}
	LOG(WARNING) << "Unsupported block major type " << majorId;
	return -ENOTSUP;
	}
	}

	auto listener = VolumeManager::Instance()->getListener();
	if (listener) listener->onDiskMetadataChanged(getId(), mSize, mLabel, mSysPath);

	return OK;
	}

	status_t Disk::readPartitions() {
	int maxMinors = getMaxMinors();
	if (maxMinors < 0) {
	return -ENOTSUP;
	}

	destroyAllVolumes();

	// Parse partition table

	std::vector<std::string> cmd;
	cmd.push_back(kSgdiskPath);
	cmd.push_back("--android-dump");
	cmd.push_back(mDevPath);

	std::vector<std::string> output;
	status_t res = ForkExecvp(cmd, &output);
	if (res != OK) {
	LOG(WARNING) << "sgdisk failed to scan " << mDevPath;

	auto listener = VolumeManager::Instance()->getListener();
	if (listener) listener->onDiskScanned(getId());

	mJustPartitioned = false;
	return res;
	}

	Table table = Table::kUnknown;
	bool foundParts = false;
	for (const auto& line : output) {
	auto split = android::base::Split(line, kSgdiskToken);
	auto it = split.begin();
	if (it == split.end()) continue;

	if (*it == "DISK") {
	if (++it == split.end()) continue;
	if (*it == "mbr") {
	table = Table::kMbr;
	} else if (*it == "gpt") {
	table = Table::kGpt;
	} else {
	LOG(WARNING) << "Invalid partition table " << *it;
	continue;
	}
	} else if (*it == "PART") {
	foundParts = true;

	if (++it == split.end()) continue;
	int i = 0;
	if (!android::base::ParseInt(*it, &i, 1, maxMinors)) {
	LOG(WARNING) << "Invalid partition number " << *it;
	continue;
	}
	dev_t partDevice = makedev(major(mDevice), minor(mDevice) + i);

	if (table == Table::kMbr) {
	if (++it == split.end()) continue;
	int type = 0;
	if (!android::base::ParseInt("0x" + *it, &type)) {
	LOG(WARNING) << "Invalid partition type " << *it;
	continue;
	}

	switch (type) {
	case 0x06: // FAT16
	case 0x07: // HPFS/NTFS/exFAT
	case 0x0b: // W95 FAT32 (LBA)
	case 0x0c: // W95 FAT32 (LBA)
	case 0x0e: // W95 FAT16 (LBA)
	createPublicVolume(partDevice);
	break;
	}
	} else if (table == Table::kGpt) {
	if (++it == split.end()) continue;
	auto typeGuid = *it;
	if (++it == split.end()) continue;
	auto partGuid = *it;

	if (android::base::EqualsIgnoreCase(typeGuid, kGptBasicData)) {
	createPublicVolume(partDevice);
	} else if (android::base::EqualsIgnoreCase(typeGuid, kGptAndroidExpand)) {
	createPrivateVolume(partDevice, partGuid);
	}
	}
	}
	}

	// Ugly last ditch effort, treat entire disk as partition
	if (table == Table::kUnknown \|\| !foundParts) {
	LOG(WARNING) << mId << " has unknown partition table; trying entire device";

	std::string fsType;
	std::string unused;
	if (ReadMetadataUntrusted(mDevPath, &fsType, &unused, &unused) == OK) {
	createPublicVolume(mDevice);
	} else {
	LOG(WARNING) << mId << " failed to identify, giving up";
	}
	}

	auto listener = VolumeManager::Instance()->getListener();
	if (listener) listener->onDiskScanned(getId());

	mJustPartitioned = false;
	return OK;
	}

	void Disk::initializePartition(std::shared_ptr<StubVolume> vol) {
	CHECK(isStub());
	CHECK(mVolumes.empty());
	mVolumes.push_back(vol);
	}

	status_t Disk::unmountAll() {
	for (const auto& vol : mVolumes) {
	vol->unmount();
	}
	return OK;
	}

	status_t Disk::partitionPublic() {
	int res;

	destroyAllVolumes();
	mJustPartitioned = true;

	// First nuke any existing partition table
	std::vector<std::string> cmd;
	cmd.push_back(kSgdiskPath);
	cmd.push_back("--zap-all");
	cmd.push_back(mDevPath);

	// Zap sometimes returns an error when it actually succeeded, so
	// just log as warning and keep rolling forward.
	if ((res = ForkExecvp(cmd)) != 0) {
	LOG(WARNING) << "Failed to zap; status " << res;
	}

	// Now let's build the new MBR table. We heavily rely on sgdisk to
	// force optimal alignment on the created partitions.
	cmd.clear();
	cmd.push_back(kSgdiskPath);
	cmd.push_back("--new=0:0:-0");
	cmd.push_back("--typecode=0:0c00");
	cmd.push_back("--gpttombr=1");
	cmd.push_back(mDevPath);

	if ((res = ForkExecvp(cmd)) != 0) {
	LOG(ERROR) << "Failed to partition; status " << res;
	return res;
	}

	return OK;
	}

	status_t Disk::partitionPrivate() {
	return partitionMixed(0);
	}

	status_t Disk::partitionMixed(int8_t ratio) {
	int res;

	destroyAllVolumes();
	mJustPartitioned = true;

	// First nuke any existing partition table
	std::vector<std::string> cmd;
	cmd.push_back(kSgdiskPath);
	cmd.push_back("--zap-all");
	cmd.push_back(mDevPath);

	// Zap sometimes returns an error when it actually succeeded, so
	// just log as warning and keep rolling forward.
	if ((res = ForkExecvp(cmd)) != 0) {
	LOG(WARNING) << "Failed to zap; status " << res;
	}

	// We've had some success above, so generate both the private partition
	// GUID and encryption key and persist them.
	std::string partGuidRaw;
	if (GenerateRandomUuid(partGuidRaw) != OK) {
	LOG(ERROR) << "Failed to generate GUID";
	return -EIO;
	}

	KeyBuffer key;
	if (!generateStorageKey(cryptfs_get_keygen(), &key)) {
	LOG(ERROR) << "Failed to generate key";
	return -EIO;
	}
	std::string keyRaw(key.begin(), key.end());

	std::string partGuid;
	StrToHex(partGuidRaw, partGuid);

	if (!WriteStringToFile(keyRaw, BuildKeyPath(partGuid))) {
	LOG(ERROR) << "Failed to persist key";
	return -EIO;
	} else {
	LOG(DEBUG) << "Persisted key for GUID " << partGuid;
	}

	// Now let's build the new GPT table. We heavily rely on sgdisk to
	// force optimal alignment on the created partitions.
	cmd.clear();
	cmd.push_back(kSgdiskPath);

	// If requested, create a public partition first. Mixed-mode partitioning
	// like this is an experimental feature.
	if (ratio > 0) {
	if (ratio < 10 \|\| ratio > 90) {
	LOG(ERROR) << "Mixed partition ratio must be between 10-90%";
	return -EINVAL;
	}

	uint64_t splitMb = ((mSize / 100) * ratio) / 1024 / 1024;
	cmd.push_back(StringPrintf("--new=0:0:+%" PRId64 "M", splitMb));
	cmd.push_back(StringPrintf("--typecode=0:%s", kGptBasicData));
	cmd.push_back("--change-name=0:shared");
	}

	// Define a metadata partition which is designed for future use; there
	// should only be one of these per physical device, even if there are
	// multiple private volumes.
	cmd.push_back("--new=0:0:+16M");
	cmd.push_back(StringPrintf("--typecode=0:%s", kGptAndroidMeta));
	cmd.push_back("--change-name=0:android_meta");

	// Define a single private partition filling the rest of disk.
	cmd.push_back("--new=0:0:-0");
	cmd.push_back(StringPrintf("--typecode=0:%s", kGptAndroidExpand));
	cmd.push_back(StringPrintf("--partition-guid=0:%s", partGuid.c_str()));
	cmd.push_back("--change-name=0:android_expand");

	cmd.push_back(mDevPath);

	if ((res = ForkExecvp(cmd)) != 0) {
	LOG(ERROR) << "Failed to partition; status " << res;
	return res;
	}

	return OK;
	}

	int Disk::getMaxMinors() {
	// Figure out maximum partition devices supported
	unsigned int majorId = major(mDevice);
	switch (majorId) {
	case kMajorBlockLoop: {
	std::string tmp;
	if (!ReadFileToString(kSysfsLoopMaxMinors, &tmp)) {
	LOG(ERROR) << "Failed to read max minors";
	return -errno;
	}
	return std::stoi(tmp);
	}
	// clang-format off
	case kMajorBlockScsiA: case kMajorBlockScsiB: case kMajorBlockScsiC:
	case kMajorBlockScsiD: case kMajorBlockScsiE: case kMajorBlockScsiF:
	case kMajorBlockScsiG: case kMajorBlockScsiH: case kMajorBlockScsiI:
	case kMajorBlockScsiJ: case kMajorBlockScsiK: case kMajorBlockScsiL:
	case kMajorBlockScsiM: case kMajorBlockScsiN: case kMajorBlockScsiO:
	case kMajorBlockScsiP: {
	// clang-format on
	// Per Documentation/devices.txt this is static
	return 15;
	}
	case kMajorBlockMmc: {
	// Per Documentation/devices.txt this is dynamic
	std::string tmp;
	if (!ReadFileToString(kSysfsMmcMaxMinors, &tmp) &&
	!ReadFileToString(kSysfsMmcMaxMinorsDeprecated, &tmp)) {
	LOG(ERROR) << "Failed to read max minors";
	return -errno;
	}
	return std::stoi(tmp);
	}
	default: {
	if (isVirtioBlkDevice(majorId)) {
	// drivers/block/virtio_blk.c has "#define PART_BITS 4", so max is
	// 2^4 - 1 = 15
	return 15;
	}
	if (isNvmeBlkDevice(majorId, mSysPath)) {
	// despite kernel nvme driver supports up to 1M minors,
	// #define NVME_MINORS (1U << MINORBITS)
	// sgdisk can not support more than 127 partitions, due to
	// #define MAX_MBR_PARTS 128
	return 127;
	}
	}
	}

	LOG(ERROR) << "Unsupported block major type " << majorId;
	return -ENOTSUP;
	}

	} // namespace vold
	} // namespace android