100 lines
3.0 KiB
Go
100 lines
3.0 KiB
Go
//go:build !windows
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package archive
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import (
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"archive/tar"
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"errors"
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"fmt"
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"math"
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"os"
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"path/filepath"
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"strings"
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"syscall"
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"golang.org/x/sys/unix"
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)
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var errInvalidArchive = errors.New("invalid archive")
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// addLongPathPrefix adds the Windows long path prefix to the path provided if
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// it does not already have it. It is a no-op on platforms other than Windows.
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func addLongPathPrefix(srcPath string) string {
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return srcPath
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}
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// getWalkRoot calculates the root path when performing a TarWithOptions.
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// We use a separate function as this is platform specific. On Linux, we
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// can't use filepath.Join(srcPath,include) because this will clean away
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// a trailing "." or "/" which may be important.
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func getWalkRoot(srcPath string, include string) string {
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return strings.TrimSuffix(srcPath, string(filepath.Separator)) + string(filepath.Separator) + include
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}
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// chmodTarEntry is used to adjust the file permissions used in tar header based
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// on the platform the archival is done.
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func chmodTarEntry(mode int64) int64 {
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return mode // noop for unix as golang APIs provide perm bits correctly
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}
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func getInodeFromStat(stat any) (uint64, error) {
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s, ok := stat.(*syscall.Stat_t)
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if !ok {
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return 0, fmt.Errorf("unexpected stat type %T", stat)
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}
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return s.Ino, nil
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}
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func getFileUIDGID(stat any) (int, int, error) {
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s, ok := stat.(*syscall.Stat_t)
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if !ok {
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return 0, 0, errors.New("cannot convert stat value to syscall.Stat_t")
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}
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return int(s.Uid), int(s.Gid), nil
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}
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// handleTarTypeBlockCharFifo is an OS-specific helper function used by
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// createTarFile to handle the following types of header: Block; Char; Fifo.
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//
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// Creating device nodes is not supported when running in a user namespace,
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// produces a [syscall.EPERM] in most cases.
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func handleTarTypeBlockCharFifo(hdr *tar.Header, dstPath string) error {
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mode := uint32(hdr.Mode & 0o7777)
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switch hdr.Typeflag {
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case tar.TypeBlock:
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mode |= unix.S_IFBLK
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case tar.TypeChar:
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mode |= unix.S_IFCHR
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case tar.TypeFifo:
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mode |= unix.S_IFIFO
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}
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// Devmajor and Devminor come straight from the (untrusted) tar header as
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// int64, but Mkdev only takes uint32. Casting a value that does not fit
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// silently truncates it, so the node created on disk would carry a
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// different major/minor than the header declares. Reject those instead of
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// creating a mismatched device.
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if hdr.Devmajor < 0 || hdr.Devmajor > math.MaxUint32 ||
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hdr.Devminor < 0 || hdr.Devminor > math.MaxUint32 {
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return fmt.Errorf("device number %d:%d for %q out of range: %w", hdr.Devmajor, hdr.Devminor, hdr.Name, errInvalidArchive)
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}
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return mknod(dstPath, mode, unix.Mkdev(uint32(hdr.Devmajor), uint32(hdr.Devminor)))
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}
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func handleLChmod(hdr *tar.Header, dstPath string, hdrInfo os.FileInfo) error {
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if hdr.Typeflag == tar.TypeLink {
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if fi, err := os.Lstat(hdr.Linkname); err == nil && (fi.Mode()&os.ModeSymlink == 0) {
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if err := os.Chmod(dstPath, hdrInfo.Mode()); err != nil {
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return err
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}
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}
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} else if hdr.Typeflag != tar.TypeSymlink {
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if err := os.Chmod(dstPath, hdrInfo.Mode()); err != nil {
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return err
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}
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}
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return nil
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}
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