moby--moby/pkg/system/xattrs_linux.go

38 lines
1.1 KiB
Go

package system // import "github.com/docker/docker/pkg/system"
import "golang.org/x/sys/unix"
// Lgetxattr retrieves the value of the extended attribute identified by attr
// and associated with the given path in the file system.
// It will returns a nil slice and nil error if the xattr is not set.
func Lgetxattr(path string, attr string) ([]byte, error) {
// Start with a 128 length byte array
dest := make([]byte, 128)
sz, errno := unix.Lgetxattr(path, attr, dest)
for errno == unix.ERANGE {
// Buffer too small, use zero-sized buffer to get the actual size
sz, errno = unix.Lgetxattr(path, attr, []byte{})
if errno != nil {
return nil, errno
}
dest = make([]byte, sz)
sz, errno = unix.Lgetxattr(path, attr, dest)
}
switch {
case errno == unix.ENODATA:
return nil, nil
case errno != nil:
return nil, errno
}
return dest[:sz], nil
}
// Lsetxattr sets the value of the extended attribute identified by attr
// and associated with the given path in the file system.
func Lsetxattr(path string, attr string, data []byte, flags int) error {
return unix.Lsetxattr(path, attr, data, flags)
}