| // Copyright 2020 The Monogon Project Authors. |
| // |
| // SPDX-License-Identifier: Apache-2.0 |
| // |
| // 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. |
| |
| // Installer creates a Metropolis image at a suitable block device based on the |
| // installer bundle present in the installation medium's ESP, after which it |
| // reboots. It's meant to be used as an init process. |
| package main |
| |
| import ( |
| "archive/zip" |
| "fmt" |
| "io" |
| "log" |
| "os" |
| "path/filepath" |
| "strings" |
| "syscall" |
| |
| "golang.org/x/sys/unix" |
| "source.monogon.dev/metropolis/node/build/mkimage/osimage" |
| "source.monogon.dev/metropolis/pkg/efivarfs" |
| "source.monogon.dev/metropolis/pkg/sysfs" |
| ) |
| |
| const mib = 1024 * 1024 |
| |
| // mountPseudoFS mounts efivarfs, devtmpfs and sysfs, used by the installer in |
| // the block device discovery stage. |
| func mountPseudoFS() error { |
| for _, m := range []struct { |
| dir string |
| fs string |
| flags uintptr |
| }{ |
| {"/sys", "sysfs", unix.MS_NOEXEC | unix.MS_NOSUID | unix.MS_NODEV}, |
| {efivarfs.Path, "efivarfs", unix.MS_NOEXEC | unix.MS_NOSUID | unix.MS_NODEV}, |
| {"/dev", "devtmpfs", unix.MS_NOEXEC | unix.MS_NOSUID}, |
| } { |
| if err := unix.Mkdir(m.dir, 0700); err != nil && !os.IsExist(err) { |
| return fmt.Errorf("couldn't create the mountpoint at %q: %w", m.dir, err) |
| } |
| if err := unix.Mount(m.fs, m.dir, m.fs, m.flags, ""); err != nil { |
| return fmt.Errorf("couldn't mount %q at %q: %w", m.fs, m.dir, err) |
| } |
| } |
| return nil |
| } |
| |
| // mountInstallerESP mounts the filesystem the installer was loaded from based |
| // on espPath, which must point to the appropriate partition block device. The |
| // filesystem is mounted at /installer. |
| func mountInstallerESP(espPath string) error { |
| // Create the mountpoint. |
| if err := unix.Mkdir("/installer", 0700); err != nil { |
| return fmt.Errorf("couldn't create the installer mountpoint: %w", err) |
| } |
| // Mount the filesystem. |
| if err := unix.Mount(espPath, "/installer", "vfat", unix.MS_NOEXEC|unix.MS_RDONLY, ""); err != nil { |
| return fmt.Errorf("couldn't mount the installer ESP (%q -> %q): %w", espPath, "/installer", err) |
| } |
| return nil |
| } |
| |
| // findInstallableBlockDevices returns names of all the block devices suitable |
| // for hosting a Metropolis installation, limited by the size expressed in |
| // bytes minSize. The install medium espDev will be excluded from the result. |
| func findInstallableBlockDevices(espDev string, minSize uint64) ([]string, error) { |
| // Use the partition's name to find and return the name of its parent |
| // device. It will be excluded from the list of suitable target devices. |
| srcDev, err := sysfs.ParentBlockDevice(espDev) |
| // Build the exclusion list containing forbidden handle prefixes. |
| exclude := []string{"dm-", "zram", "ram", "loop", srcDev} |
| |
| // Get the block device handles by looking up directory contents. |
| const blkDirPath = "/sys/class/block" |
| blkDevs, err := os.ReadDir(blkDirPath) |
| if err != nil { |
| return nil, fmt.Errorf("couldn't read %q: %w", blkDirPath, err) |
| } |
| // Iterate over the handles, skipping any block device that either points to |
| // a partition, matches the exclusion list, or is smaller than minSize. |
| var suitable []string |
| probeLoop: |
| for _, devInfo := range blkDevs { |
| // Skip devices according to the exclusion list. |
| for _, prefix := range exclude { |
| if strings.HasPrefix(devInfo.Name(), prefix) { |
| continue probeLoop |
| } |
| } |
| |
| // Skip partition symlinks. |
| if _, err := os.Stat(filepath.Join(blkDirPath, devInfo.Name(), "partition")); err == nil { |
| continue |
| } else if !os.IsNotExist(err) { |
| return nil, fmt.Errorf("while probing sysfs: %w", err) |
| } |
| |
| // Skip devices of insufficient size. |
| devPath := filepath.Join("/dev", devInfo.Name()) |
| dev, err := os.Open(devPath) |
| if err != nil { |
| return nil, fmt.Errorf("couldn't open a block device at %q: %w", devPath, err) |
| } |
| size, err := unix.IoctlGetInt(int(dev.Fd()), unix.BLKGETSIZE64) |
| dev.Close() |
| if err != nil { |
| return nil, fmt.Errorf("couldn't probe the size of %q: %w", devPath, err) |
| } |
| if uint64(size) < minSize { |
| continue |
| } |
| |
| suitable = append(suitable, devInfo.Name()) |
| } |
| return suitable, nil |
| } |
| |
| // rereadPartitionTable causes the kernel to read the partition table present |
| // in the block device at blkdevPath. It may return an error. |
| func rereadPartitionTable(blkdevPath string) error { |
| dev, err := os.Open(blkdevPath) |
| if err != nil { |
| return fmt.Errorf("couldn't open the block device at %q: %w", blkdevPath, err) |
| } |
| defer dev.Close() |
| ret, err := unix.IoctlRetInt(int(dev.Fd()), unix.BLKRRPART) |
| if err != nil { |
| return fmt.Errorf("while doing an ioctl: %w", err) |
| } |
| if syscall.Errno(ret) == unix.EINVAL { |
| return fmt.Errorf("got an EINVAL from BLKRRPART ioctl") |
| } |
| return nil |
| } |
| |
| // initializeSystemPartition writes image contents to the node's system |
| // partition using the block device abstraction layer as opposed to slower |
| // go-diskfs. tgtBlkdev must contain a path pointing to the block device |
| // associated with the system partition. It may return an error. |
| func initializeSystemPartition(image io.Reader, tgtBlkdev string) error { |
| // Check that tgtBlkdev points at an actual block device. |
| info, err := os.Stat(tgtBlkdev) |
| if err != nil { |
| return fmt.Errorf("couldn't stat the system partition at %q: %w", tgtBlkdev, err) |
| } |
| if info.Mode()&os.ModeDevice == 0 { |
| return fmt.Errorf("system partition path %q doesn't point to a block device", tgtBlkdev) |
| } |
| |
| // Get the system partition's file descriptor. |
| sys, err := os.OpenFile(tgtBlkdev, os.O_WRONLY, 0600) |
| if err != nil { |
| return fmt.Errorf("couldn't open the system partition at %q: %w", tgtBlkdev, err) |
| } |
| defer sys.Close() |
| // Copy the system partition contents. Use a bigger buffer to optimize disk |
| // writes. |
| buf := make([]byte, mib) |
| if _, err := io.CopyBuffer(sys, image, buf); err != nil { |
| return fmt.Errorf("couldn't copy partition contents: %w", err) |
| } |
| return nil |
| } |
| |
| func main() { |
| // Mount sysfs, devtmpfs and efivarfs. |
| if err := mountPseudoFS(); err != nil { |
| log.Fatalf("while mounting pseudo-filesystems: %s", err.Error()) |
| } |
| // Read the installer ESP UUID from efivarfs. |
| espUuid, err := efivarfs.ReadLoaderDevicePartUUID() |
| if err != nil { |
| log.Fatalf("while reading the installer ESP UUID: %s", err.Error()) |
| } |
| // Look up the installer partition based on espUuid. |
| espDev, err := sysfs.DeviceByPartUUID(espUuid) |
| espPath := filepath.Join("/dev", espDev) |
| if err != nil { |
| log.Fatalf("while resolving the installer device handle: %s", err.Error()) |
| } |
| // Mount the installer partition. The installer bundle will be read from it. |
| if err := mountInstallerESP(espPath); err != nil { |
| log.Fatalf("while mounting the installer ESP: %s", err.Error()) |
| } |
| |
| nodeParameters, err := os.Open("/installer/EFI/metropolis-installer/nodeparams.pb") |
| if err != nil { |
| log.Fatalf("failed to open node parameters from ESP: %v", err) |
| } |
| |
| // TODO(lorenz): Replace with proper bundles |
| bundle, err := zip.OpenReader("/installer/EFI/metropolis-installer/bundle.bin") |
| if err != nil { |
| log.Fatalf("failed to open node bundle from ESP: %v", err) |
| } |
| defer bundle.Close() |
| efiPayload, err := bundle.Open("kernel_efi.efi") |
| if err != nil { |
| log.Fatalf("Cannot open EFI payload in bundle: %v", err) |
| } |
| defer efiPayload.Close() |
| systemImage, err := bundle.Open("rootfs.img") |
| if err != nil { |
| log.Fatalf("Cannot open system image in bundle: %v", err) |
| } |
| defer systemImage.Close() |
| |
| // Build the osimage parameters. |
| installParams := osimage.Params{ |
| PartitionSize: osimage.PartitionSizeInfo{ |
| // ESP is the size of the node ESP partition, expressed in mebibytes. |
| ESP: 128, |
| // System is the size of the node system partition, expressed in |
| // mebibytes. |
| System: 4096, |
| // Data must be nonzero in order for the data partition to be created. |
| // osimage will extend the data partition to fill all the available space |
| // whenever it's writing to block devices, such as now. |
| Data: 128, |
| }, |
| // Due to a bug in go-diskfs causing slow writes, SystemImage is explicitly |
| // marked unused here, as system partition contents will be written using |
| // a workaround below instead. |
| // TODO(mateusz@monogon.tech): Address that bug either by patching go-diskfs |
| // or rewriting osimage. |
| SystemImage: nil, |
| |
| EFIPayload: efiPayload, |
| NodeParameters: nodeParameters, |
| } |
| // Calculate the minimum target size based on the installation parameters. |
| minSize := uint64((installParams.PartitionSize.ESP + |
| installParams.PartitionSize.System + |
| installParams.PartitionSize.Data + 1) * mib) |
| |
| // Look for suitable block devices, given the minimum size. |
| blkDevs, err := findInstallableBlockDevices(espDev, minSize) |
| if err != nil { |
| log.Fatal(err.Error()) |
| } |
| if len(blkDevs) == 0 { |
| log.Fatal("couldn't find a suitable block device.") |
| } |
| // Set the first suitable block device found as the installation target. |
| tgtBlkdevName := blkDevs[0] |
| // Update the osimage parameters with a path pointing at the target device. |
| tgtBlkdevPath := filepath.Join("/dev", tgtBlkdevName) |
| installParams.OutputPath = tgtBlkdevPath |
| |
| // Use osimage to partition the target block device and set up its ESP. |
| // Create will return an EFI boot entry on success. |
| log.Printf("Installing to %s\n", tgtBlkdevPath) |
| be, err := osimage.Create(&installParams) |
| if err != nil { |
| log.Fatalf("while installing: %s", err.Error()) |
| } |
| // The target device's partition table has just been updated. Re-read it to |
| // make the node system partition reachable through /dev. |
| if err := rereadPartitionTable(tgtBlkdevPath); err != nil { |
| log.Fatalf("while re-reading the partition table of %q: %s", tgtBlkdevPath, err.Error()) |
| } |
| // Look up the node's system partition path to be later used in the |
| // initialization step. It's always the second partition, right after |
| // the ESP. |
| sysBlkdevName, err := sysfs.PartitionBlockDevice(tgtBlkdevName, 2) |
| if err != nil { |
| log.Fatalf("while looking up the system partition: %s", err.Error()) |
| } |
| sysBlkdevPath := filepath.Join("/dev", sysBlkdevName) |
| // Copy the system partition contents. |
| if err := initializeSystemPartition(systemImage, sysBlkdevPath); err != nil { |
| log.Fatalf("while initializing the system partition at %q: %s", sysBlkdevPath, err.Error()) |
| } |
| |
| // Create an EFI boot entry for Metropolis. |
| en, err := efivarfs.CreateBootEntry(be) |
| if err != nil { |
| log.Fatalf("while creating a boot entry: %s", err.Error()) |
| } |
| // Erase the preexisting boot order, leaving Metropolis as the only option. |
| if err := efivarfs.SetBootOrder(&efivarfs.BootOrder{uint16(en)}); err != nil { |
| log.Fatalf("while adjusting the boot order: %s", err.Error()) |
| } |
| |
| // Reboot. |
| unix.Sync() |
| log.Print("Installation completed. Rebooting.") |
| unix.Reboot(unix.LINUX_REBOOT_CMD_RESTART) |
| } |