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/*
* Copyright (C) 2018 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 "liblp/partition_opener.h"
#if defined(__linux__)
#include <linux/fs.h>
#endif
#if !defined(_WIN32)
#include <sys/ioctl.h>
#endif
#include <sys/types.h>
#include <unistd.h>
#include <android-base/file.h>
#include <android-base/strings.h>
#include "utility.h"
namespace android {
namespace fs_mgr {
using android::base::unique_fd;
namespace {
std::string GetPartitionAbsolutePath(const std::string& path) {
#if !defined(__ANDROID__)
return path;
#else
if (android::base::StartsWith(path, "/")) {
return path;
}
auto by_name = "/dev/block/by-name/" + path;
if (access(by_name.c_str(), F_OK) != 0) {
// If the by-name symlink doesn't exist, as a special case we allow
// certain devices to be used as partition names. This can happen if a
// Dynamic System Update is installed to an sdcard, which won't be in
// the boot device list.
//
// mmcblk* is allowed because most devices in /dev/block are not valid for
// storing fiemaps.
if (android::base::StartsWith(path, "mmcblk")) {
return "/dev/block/" + path;
}
}
return by_name;
#endif
}
bool GetBlockDeviceInfo(const std::string& block_device, BlockDeviceInfo* device_info) {
#if defined(__linux__)
unique_fd fd = GetControlFileOrOpen(block_device.c_str(), O_RDONLY);
if (fd < 0) {
PERROR << __PRETTY_FUNCTION__ << "open '" << block_device << "' failed";
return false;
}
if (!GetDescriptorSize(fd, &device_info->size)) {
return false;
}
if (ioctl(fd, BLKIOMIN, &device_info->alignment) < 0) {
PERROR << __PRETTY_FUNCTION__ << "BLKIOMIN failed on " << block_device;
return false;
}
int alignment_offset;
if (ioctl(fd, BLKALIGNOFF, &alignment_offset) < 0) {
PERROR << __PRETTY_FUNCTION__ << "BLKALIGNOFF failed on " << block_device;
return false;
}
// The kernel can return -1 here when misaligned devices are stacked (i.e.
// device-mapper).
if (alignment_offset == -1) {
alignment_offset = 0;
}
int logical_block_size;
if (ioctl(fd, BLKSSZGET, &logical_block_size) < 0) {
PERROR << __PRETTY_FUNCTION__ << "BLKSSZGET failed on " << block_device;
return false;
}
device_info->alignment_offset = static_cast<uint32_t>(alignment_offset);
device_info->logical_block_size = static_cast<uint32_t>(logical_block_size);
device_info->partition_name = android::base::Basename(block_device);
return true;
#else
(void)block_device;
(void)device_info;
LERROR << __PRETTY_FUNCTION__ << ": Not supported on this operating system.";
return false;
#endif
}
} // namespace
unique_fd PartitionOpener::Open(const std::string& partition_name, int flags) const {
std::string path = GetPartitionAbsolutePath(partition_name);
return GetControlFileOrOpen(path.c_str(), flags | O_CLOEXEC);
}
bool PartitionOpener::GetInfo(const std::string& partition_name, BlockDeviceInfo* info) const {
std::string path = GetPartitionAbsolutePath(partition_name);
return GetBlockDeviceInfo(path, info);
}
std::string PartitionOpener::GetDeviceString(const std::string& partition_name) const {
return GetPartitionAbsolutePath(partition_name);
}
} // namespace fs_mgr
} // namespace android
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