| // +build linux |
| |
| package overlay |
| |
| import ( |
| "fmt" |
| "io" |
| "os" |
| "path/filepath" |
| "syscall" |
| |
| "github.com/docker/docker/pkg/system" |
| ) |
| |
| type CopyFlags int |
| |
| const ( |
| CopyHardlink CopyFlags = 1 << iota |
| ) |
| |
| func copyRegular(srcPath, dstPath string, mode os.FileMode) error { |
| srcFile, err := os.Open(srcPath) |
| if err != nil { |
| return err |
| } |
| defer srcFile.Close() |
| |
| dstFile, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE, mode) |
| if err != nil { |
| return err |
| } |
| defer dstFile.Close() |
| |
| _, err = io.Copy(dstFile, srcFile) |
| |
| return err |
| } |
| |
| func copyXattr(srcPath, dstPath, attr string) error { |
| data, err := system.Lgetxattr(srcPath, attr) |
| if err != nil { |
| return err |
| } |
| if data != nil { |
| if err := system.Lsetxattr(dstPath, attr, data, 0); err != nil { |
| return err |
| } |
| } |
| return nil |
| } |
| |
| func copyDir(srcDir, dstDir string, flags CopyFlags) error { |
| err := filepath.Walk(srcDir, func(srcPath string, f os.FileInfo, err error) error { |
| if err != nil { |
| return err |
| } |
| |
| // Rebase path |
| relPath, err := filepath.Rel(srcDir, srcPath) |
| if err != nil { |
| return err |
| } |
| |
| dstPath := filepath.Join(dstDir, relPath) |
| if err != nil { |
| return err |
| } |
| |
| stat, ok := f.Sys().(*syscall.Stat_t) |
| if !ok { |
| return fmt.Errorf("Unable to get raw syscall.Stat_t data for %s", srcPath) |
| } |
| |
| isHardlink := false |
| |
| switch f.Mode() & os.ModeType { |
| case 0: // Regular file |
| if flags&CopyHardlink != 0 { |
| isHardlink = true |
| if err := os.Link(srcPath, dstPath); err != nil { |
| return err |
| } |
| } else { |
| if err := copyRegular(srcPath, dstPath, f.Mode()); err != nil { |
| return err |
| } |
| } |
| |
| case os.ModeDir: |
| if err := os.Mkdir(dstPath, f.Mode()); err != nil && !os.IsExist(err) { |
| return err |
| } |
| |
| case os.ModeSymlink: |
| link, err := os.Readlink(srcPath) |
| if err != nil { |
| return err |
| } |
| |
| if err := os.Symlink(link, dstPath); err != nil { |
| return err |
| } |
| |
| case os.ModeNamedPipe: |
| fallthrough |
| case os.ModeSocket: |
| if err := syscall.Mkfifo(dstPath, stat.Mode); err != nil { |
| return err |
| } |
| |
| case os.ModeDevice: |
| if err := syscall.Mknod(dstPath, stat.Mode, int(stat.Rdev)); err != nil { |
| return err |
| } |
| |
| default: |
| return fmt.Errorf("Unknown file type for %s\n", srcPath) |
| } |
| |
| // Everything below is copying metadata from src to dst. All this metadata |
| // already shares an inode for hardlinks. |
| if isHardlink { |
| return nil |
| } |
| |
| if err := os.Lchown(dstPath, int(stat.Uid), int(stat.Gid)); err != nil { |
| return err |
| } |
| |
| if err := copyXattr(srcPath, dstPath, "security.capability"); err != nil { |
| return err |
| } |
| |
| // We need to copy this attribute if it appears in an overlay upper layer, as |
| // this function is used to copy those. It is set by overlay if a directory |
| // is removed and then re-created and should not inherit anything from the |
| // same dir in the lower dir. |
| if err := copyXattr(srcPath, dstPath, "trusted.overlay.opaque"); err != nil { |
| return err |
| } |
| |
| isSymlink := f.Mode()&os.ModeSymlink != 0 |
| |
| // There is no LChmod, so ignore mode for symlink. Also, this |
| // must happen after chown, as that can modify the file mode |
| if !isSymlink { |
| if err := os.Chmod(dstPath, f.Mode()); err != nil { |
| return err |
| } |
| } |
| |
| ts := []syscall.Timespec{stat.Atim, stat.Mtim} |
| // syscall.UtimesNano doesn't support a NOFOLLOW flag atm, and |
| if !isSymlink { |
| if err := system.UtimesNano(dstPath, ts); err != nil { |
| return err |
| } |
| } else { |
| if err := system.LUtimesNano(dstPath, ts); err != nil { |
| return err |
| } |
| } |
| return nil |
| }) |
| return err |
| } |