daa1ea522b
Details about CimFs project are discussed in #8346 Signed-off-by: Amit Barve <ambarve@microsoft.com>
135 lines
3.3 KiB
Go
135 lines
3.3 KiB
Go
//go:build windows
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// +build windows
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package cimfs
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import (
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"bytes"
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"context"
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"encoding/binary"
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"fmt"
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"os"
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"path/filepath"
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"github.com/Microsoft/hcsshim/internal/log"
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"github.com/Microsoft/hcsshim/pkg/cimfs/format"
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)
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var (
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// Equivalent to SDDL of "D:NO_ACCESS_CONTROL".
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nullSd = []byte{1, 0, 4, 128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
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)
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type OpError struct {
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Cim string
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Op string
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Err error
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}
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func (e *OpError) Error() string {
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s := "cim " + e.Op + " " + e.Cim
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s += ": " + e.Err.Error()
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return s
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}
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// PathError is the error type returned by most functions in this package.
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type PathError struct {
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Cim string
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Op string
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Path string
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Err error
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}
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func (e *PathError) Error() string {
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s := "cim " + e.Op + " " + e.Cim
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s += ":" + e.Path
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s += ": " + e.Err.Error()
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return s
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}
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type LinkError struct {
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Cim string
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Op string
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Old string
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New string
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Err error
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}
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func (e *LinkError) Error() string {
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return "cim " + e.Op + " " + e.Old + " " + e.New + ": " + e.Err.Error()
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}
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func validateHeader(h *format.CommonHeader) error {
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if !bytes.Equal(h.Magic[:], format.MagicValue[:]) {
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return fmt.Errorf("not a cim file")
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}
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if h.Version.Major > format.CurrentVersion.Major || h.Version.Major < format.MinSupportedVersion.Major {
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return fmt.Errorf("unsupported cim version. cim version %v must be between %v & %v", h.Version, format.MinSupportedVersion, format.CurrentVersion)
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}
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return nil
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}
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func readFilesystemHeader(f *os.File) (format.FilesystemHeader, error) {
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var fsh format.FilesystemHeader
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if err := binary.Read(f, binary.LittleEndian, &fsh); err != nil {
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return fsh, fmt.Errorf("reading filesystem header: %w", err)
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}
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if err := validateHeader(&fsh.Common); err != nil {
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return fsh, fmt.Errorf("validating filesystem header: %w", err)
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}
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return fsh, nil
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}
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// Returns the paths of all the objectID files associated with the cim at `cimPath`.
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func getObjectIDFilePaths(ctx context.Context, cimPath string) ([]string, error) {
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f, err := os.Open(cimPath)
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if err != nil {
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return []string{}, fmt.Errorf("open cim file %s: %w", cimPath, err)
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}
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defer f.Close()
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fsh, err := readFilesystemHeader(f)
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if err != nil {
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return []string{}, fmt.Errorf("readingp cim header: %w", err)
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}
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paths := []string{}
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for i := 0; i < int(fsh.Regions.Count); i++ {
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path := filepath.Join(filepath.Dir(cimPath), fmt.Sprintf("%s_%v_%d", format.ObjectIDFileName, fsh.Regions.ID, i))
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if _, err := os.Stat(path); err == nil {
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paths = append(paths, path)
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} else {
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log.G(ctx).WithError(err).Warnf("stat for object file %s", path)
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}
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}
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return paths, nil
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}
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// Returns the paths of all the region files associated with the cim at `cimPath`.
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func getRegionFilePaths(ctx context.Context, cimPath string) ([]string, error) {
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f, err := os.Open(cimPath)
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if err != nil {
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return []string{}, fmt.Errorf("open cim file %s: %w", cimPath, err)
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}
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defer f.Close()
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fsh, err := readFilesystemHeader(f)
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if err != nil {
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return []string{}, fmt.Errorf("reading cim header: %w", err)
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}
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paths := []string{}
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for i := 0; i < int(fsh.Regions.Count); i++ {
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path := filepath.Join(filepath.Dir(cimPath), fmt.Sprintf("%s_%v_%d", format.RegionFileName, fsh.Regions.ID, i))
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if _, err := os.Stat(path); err == nil {
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paths = append(paths, path)
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} else {
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log.G(ctx).WithError(err).Warnf("stat for region file %s", path)
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}
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}
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return paths, nil
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}
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