volume_manager/Disk.cpp - LeafOS-Project/android_bootable_recovery - Gitiles

 /*
  * Copyright (C) 2015 The Android Open Source Project
  * Copyright (C) 2019 The LineageOS 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 "PublicVolume.h"
 #include <volume_manager/ResponseCode.h>
 #include <volume_manager/VolumeManager.h>
 #include "Utils.h"
 #include "VolumeBase.h"

 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <diskconfig/diskconfig.h>

 #include <sgdisk.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::WriteStringToFile;
 using android::base::StringPrintf;

 namespace android {
 namespace volmgr {

 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 char* kGptBasicData = "EBD0A0A2-B9E5-4433-87C0-68B6B72699C7";
 static const char* kGptLinuxFilesystem = "0FC63DAF-8483-4772-8E79-3D69D8477DE4";

 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;
 }

 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),
       mSkipChange(false) {
     mId = StringPrintf("disk:%u_%u", major(device), minor(device));
     mEventPath = eventPath;
     mSysPath = StringPrintf("/sys/%s", eventPath.c_str());
     mDevPath = StringPrintf("/dev/block/volmgr/%s", mId.c_str());
     CreateDeviceNode(mDevPath, mDevice);
 }

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

 void Disk::getVolumeInfo(std::vector<VolumeInfo>& info) {
     for (auto vol : mVolumes) {
         info.push_back(VolumeInfo(vol.get()));
     }
 }

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

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

 status_t Disk::create() {
     CHECK(!mCreated);
     mCreated = true;
     VolumeManager::Instance()->notifyEvent(ResponseCode::DiskCreated, StringPrintf("%d", mFlags));
     readMetadata();
     readPartitions();
     return OK;
 }

 status_t Disk::destroy() {
     CHECK(mCreated);
     destroyAllVolumes();
     mCreated = false;
     VolumeManager::Instance()->notifyEvent(ResponseCode::DiskDestroyed);
     return OK;
 }

 void Disk::createPublicVolume(dev_t device, const std::string& fstype /* = "" */,
                               const std::string& mntopts /* = "" */) {
     auto vol = std::shared_ptr<VolumeBase>(new PublicVolume(device, mNickname, fstype, mntopts));

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

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

 status_t Disk::readMetadata() {
     if (mSkipChange) {
         return OK;
     }

     mSize = -1;
     mLabel.clear();

     int fd = open(mDevPath.c_str(), O_RDONLY | O_CLOEXEC);
     if (fd != -1) {
         if (ioctl(fd, BLKGETSIZE64, &mSize)) {
             mSize = -1;
         }
         close(fd);
     }

     unsigned int majorId = major(mDevice);
     switch (majorId) {
         case kMajorBlockLoop: {
             mLabel = "Virtual";
             break;
         }
         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: {
             std::string path(mSysPath + "/device/vendor");
             std::string tmp;
             if (!ReadFileToString(path, &tmp)) {
                 PLOG(WARNING) << "Failed to read vendor from " << path;
                 return -errno;
             }
             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;
             }
             uint64_t manfid = strtoll(tmp.c_str(), nullptr, 16);
             // 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) {
                 case 0x000003:
                     mLabel = "SanDisk";
                     break;
                 case 0x00001b:
                     mLabel = "Samsung";
                     break;
                 case 0x000028:
                     mLabel = "Lexar";
                     break;
                 case 0x000074:
                     mLabel = "Transcend";
                     break;
             }
             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;
             }
             LOG(WARNING) << "Unsupported block major type " << majorId;
             return -ENOTSUP;
         }
     }

     VolumeManager::Instance()->notifyEvent(ResponseCode::DiskSizeChanged,
                                            StringPrintf("%" PRIu64, mSize));
     VolumeManager::Instance()->notifyEvent(ResponseCode::DiskLabelChanged, mLabel);
     VolumeManager::Instance()->notifyEvent(ResponseCode::DiskSysPathChanged, mSysPath);
     return OK;
 }

 status_t Disk::readPartitions() {
     int8_t maxMinors = getMaxMinors();
     if (maxMinors < 0) {
         return -ENOTSUP;
     }

     if (mSkipChange) {
         mSkipChange = false;
         LOG(INFO) << "Skip first change";
         return OK;
     }

     destroyAllVolumes();

     // Parse partition table
     sgdisk_partition_table ptbl;
     std::vector<sgdisk_partition> partitions;
     int res = sgdisk_read(mDevPath.c_str(), ptbl, partitions);
     if (res != 0) {
         LOG(WARNING) << "sgdisk failed to scan " << mDevPath;
         VolumeManager::Instance()->notifyEvent(ResponseCode::DiskScanned);
         return res;
     }

     Table table = Table::kUnknown;
     bool foundParts = false;

     switch (ptbl.type) {
         case MBR:
             table = Table::kMbr;
             break;
         case GPT:
             table = Table::kGpt;
             break;
         default:
             table = Table::kUnknown;
     }

     foundParts = partitions.size() > 0;
     for (const auto& part : partitions) {
         if (part.num <= 0 || part.num > maxMinors) {
             LOG(WARNING) << mId << " is ignoring partition " << part.num
                          << " beyond max supported devices";
             continue;
         }
         dev_t partDevice = makedev(major(mDevice), minor(mDevice) + part.num);
         if (table == Table::kMbr) {
             switch (strtol(part.type.c_str(), nullptr, 16)) {
                 case 0x06:  // FAT16
                 case 0x07:  // NTFS/exFAT
                 case 0x0b:  // W95 FAT32 (LBA)
                 case 0x0c:  // W95 FAT32 (LBA)
                 case 0x0e:  // W95 FAT16 (LBA)
                 case 0x83:  // Linux EXT4/F2FS/...
                     createPublicVolume(partDevice);
                     break;
             }
         } else if (table == Table::kGpt) {
             if (!strcasecmp(part.guid.c_str(), kGptBasicData) ||
                 !strcasecmp(part.guid.c_str(), kGptLinuxFilesystem)) {
                 createPublicVolume(partDevice);
             }
         }
     }

     // 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";
         }
     }

     VolumeManager::Instance()->notifyEvent(ResponseCode::DiskScanned);
     return OK;
 }

 status_t Disk::unmountAll() {
     for (const auto& vol : mVolumes) {
         vol->unmount();
     }
     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 atoi(tmp.c_str());
         }
         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: {
             // 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 atoi(tmp.c_str());
         }
         default: {
             if (isVirtioBlkDevice(majorId)) {
                 // drivers/block/virtio_blk.c has "#define PART_BITS 4", so max is
                 // 2^4 - 1 = 15
                 return 15;
             }
         }
     }

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

 }  // namespace volmgr
 }  // namespace android
	/*
	* Copyright (C) 2015 The Android Open Source Project
	* Copyright (C) 2019 The LineageOS 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 "PublicVolume.h"
	#include <volume_manager/ResponseCode.h>
	#include <volume_manager/VolumeManager.h>
	#include "Utils.h"
	#include "VolumeBase.h"

	#include <android-base/file.h>
	#include <android-base/logging.h>
	#include <android-base/properties.h>
	#include <android-base/stringprintf.h>
	#include <diskconfig/diskconfig.h>

	#include <sgdisk.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::WriteStringToFile;
	using android::base::StringPrintf;

	namespace android {
	namespace volmgr {

	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 char* kGptBasicData = "EBD0A0A2-B9E5-4433-87C0-68B6B72699C7";
	static const char* kGptLinuxFilesystem = "0FC63DAF-8483-4772-8E79-3D69D8477DE4";

	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;
	}

	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),
	mSkipChange(false) {
	mId = StringPrintf("disk:%u_%u", major(device), minor(device));
	mEventPath = eventPath;
	mSysPath = StringPrintf("/sys/%s", eventPath.c_str());
	mDevPath = StringPrintf("/dev/block/volmgr/%s", mId.c_str());
	CreateDeviceNode(mDevPath, mDevice);
	}

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

	void Disk::getVolumeInfo(std::vector<VolumeInfo>& info) {
	for (auto vol : mVolumes) {
	info.push_back(VolumeInfo(vol.get()));
	}
	}

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

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

	status_t Disk::create() {
	CHECK(!mCreated);
	mCreated = true;
	VolumeManager::Instance()->notifyEvent(ResponseCode::DiskCreated, StringPrintf("%d", mFlags));
	readMetadata();
	readPartitions();
	return OK;
	}

	status_t Disk::destroy() {
	CHECK(mCreated);
	destroyAllVolumes();
	mCreated = false;
	VolumeManager::Instance()->notifyEvent(ResponseCode::DiskDestroyed);
	return OK;
	}

	void Disk::createPublicVolume(dev_t device, const std::string& fstype /* = "" */,
	const std::string& mntopts /* = "" */) {
	auto vol = std::shared_ptr<VolumeBase>(new PublicVolume(device, mNickname, fstype, mntopts));

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

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

	status_t Disk::readMetadata() {
	if (mSkipChange) {
	return OK;
	}

	mSize = -1;
	mLabel.clear();

	int fd = open(mDevPath.c_str(), O_RDONLY \| O_CLOEXEC);
	if (fd != -1) {
	if (ioctl(fd, BLKGETSIZE64, &mSize)) {
	mSize = -1;
	}
	close(fd);
	}

	unsigned int majorId = major(mDevice);
	switch (majorId) {
	case kMajorBlockLoop: {
	mLabel = "Virtual";
	break;
	}
	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: {
	std::string path(mSysPath + "/device/vendor");
	std::string tmp;
	if (!ReadFileToString(path, &tmp)) {
	PLOG(WARNING) << "Failed to read vendor from " << path;
	return -errno;
	}
	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;
	}
	uint64_t manfid = strtoll(tmp.c_str(), nullptr, 16);
	// 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) {
	case 0x000003:
	mLabel = "SanDisk";
	break;
	case 0x00001b:
	mLabel = "Samsung";
	break;
	case 0x000028:
	mLabel = "Lexar";
	break;
	case 0x000074:
	mLabel = "Transcend";
	break;
	}
	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;
	}
	LOG(WARNING) << "Unsupported block major type " << majorId;
	return -ENOTSUP;
	}
	}

	VolumeManager::Instance()->notifyEvent(ResponseCode::DiskSizeChanged,
	StringPrintf("%" PRIu64, mSize));
	VolumeManager::Instance()->notifyEvent(ResponseCode::DiskLabelChanged, mLabel);
	VolumeManager::Instance()->notifyEvent(ResponseCode::DiskSysPathChanged, mSysPath);
	return OK;
	}

	status_t Disk::readPartitions() {
	int8_t maxMinors = getMaxMinors();
	if (maxMinors < 0) {
	return -ENOTSUP;
	}

	if (mSkipChange) {
	mSkipChange = false;
	LOG(INFO) << "Skip first change";
	return OK;
	}

	destroyAllVolumes();

	// Parse partition table
	sgdisk_partition_table ptbl;
	std::vector<sgdisk_partition> partitions;
	int res = sgdisk_read(mDevPath.c_str(), ptbl, partitions);
	if (res != 0) {
	LOG(WARNING) << "sgdisk failed to scan " << mDevPath;
	VolumeManager::Instance()->notifyEvent(ResponseCode::DiskScanned);
	return res;
	}

	Table table = Table::kUnknown;
	bool foundParts = false;

	switch (ptbl.type) {
	case MBR:
	table = Table::kMbr;
	break;
	case GPT:
	table = Table::kGpt;
	break;
	default:
	table = Table::kUnknown;
	}

	foundParts = partitions.size() > 0;
	for (const auto& part : partitions) {
	if (part.num <= 0 \|\| part.num > maxMinors) {
	LOG(WARNING) << mId << " is ignoring partition " << part.num
	<< " beyond max supported devices";
	continue;
	}
	dev_t partDevice = makedev(major(mDevice), minor(mDevice) + part.num);
	if (table == Table::kMbr) {
	switch (strtol(part.type.c_str(), nullptr, 16)) {
	case 0x06: // FAT16
	case 0x07: // NTFS/exFAT
	case 0x0b: // W95 FAT32 (LBA)
	case 0x0c: // W95 FAT32 (LBA)
	case 0x0e: // W95 FAT16 (LBA)
	case 0x83: // Linux EXT4/F2FS/...
	createPublicVolume(partDevice);
	break;
	}
	} else if (table == Table::kGpt) {
	if (!strcasecmp(part.guid.c_str(), kGptBasicData) \|\|
	!strcasecmp(part.guid.c_str(), kGptLinuxFilesystem)) {
	createPublicVolume(partDevice);
	}
	}
	}

	// 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";
	}
	}

	VolumeManager::Instance()->notifyEvent(ResponseCode::DiskScanned);
	return OK;
	}

	status_t Disk::unmountAll() {
	for (const auto& vol : mVolumes) {
	vol->unmount();
	}
	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 atoi(tmp.c_str());
	}
	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: {
	// 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 atoi(tmp.c_str());
	}
	default: {
	if (isVirtioBlkDevice(majorId)) {
	// drivers/block/virtio_blk.c has "#define PART_BITS 4", so max is
	// 2^4 - 1 = 15
	return 15;
	}
	}
	}

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

	} // namespace volmgr
	} // namespace android