diff --git a/usr.sbin/kldxref/ef.h b/usr.sbin/kldxref/ef.h
index f10af49fafba..94aaca279a80 100644
--- a/usr.sbin/kldxref/ef.h
+++ b/usr.sbin/kldxref/ef.h
@@ -1,72 +1,105 @@
+/*-
+ * SPDX-License-Identifier: BSD-4-Clause
+ *
+ * Copyright (c) 2000, Boris Popov
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *    This product includes software developed by Boris Popov.
+ * 4. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
 
 #ifndef _EF_H_
 #define _EF_H_
 
 #define	EFT_KLD		1
 #define	EFT_KERNEL	2
 
 #define EF_RELOC_REL	1
 #define EF_RELOC_RELA	2
 
 #define EF_GET_TYPE(ef) \
     (ef)->ef_ops->get_type((ef)->ef_ef)
 #define EF_CLOSE(ef) \
     (ef)->ef_ops->close((ef)->ef_ef)
 #define EF_READ(ef, offset, len, dest) \
     (ef)->ef_ops->read((ef)->ef_ef, offset, len, dest)
 #define EF_READ_ENTRY(ef, offset, len, ptr) \
     (ef)->ef_ops->read_entry((ef)->ef_ef, offset, len, ptr)
 #define EF_SEG_READ(ef, offset, len, dest) \
     (ef)->ef_ops->seg_read((ef)->ef_ef, offset, len, dest)
 #define EF_SEG_READ_REL(ef, offset, len, dest) \
     (ef)->ef_ops->seg_read_rel((ef)->ef_ef, offset, len, dest)
 #define EF_SEG_READ_STRING(ef, offset, len, dest) \
     (ef)->ef_ops->seg_read_string((ef)->ef_ef, offset, len, dest)
 #define EF_SEG_READ_ENTRY(ef, offset, len, ptr) \
     (ef)->ef_ops->seg_read_entry((ef)->kf_ef, offset, len, ptr)
 #define EF_SEG_READ_ENTRY_REL(ef, offset, len, ptr) \
     (ef)->ef_ops->seg_read_entry_rel((ef)->ef_ef, offset, len, ptr)
 #define EF_SYMADDR(ef, symidx) \
     (ef)->ef_ops->symaddr((ef)->ef_ef, symidx)
 #define EF_LOOKUP_SET(ef, name, startp, stopp, countp) \
     (ef)->ef_ops->lookup_set((ef)->ef_ef, name, startp, stopp, countp)
 #define EF_LOOKUP_SYMBOL(ef, name, sym) \
     (ef)->ef_ops->lookup_symbol((ef)->ef_ef, name, sym)
 
 /* XXX, should have a different name. */
 typedef struct ef_file *elf_file_t;
 
 struct elf_file_ops {
 	int (*get_type)(elf_file_t ef);
 	int (*close)(elf_file_t ef);
 	int (*read)(elf_file_t ef, Elf_Off offset, size_t len, void* dest);
 	int (*read_entry)(elf_file_t ef, Elf_Off offset, size_t len,
 	    void **ptr);
 	int (*seg_read)(elf_file_t ef, Elf_Off offset, size_t len, void *dest);
 	int (*seg_read_rel)(elf_file_t ef, Elf_Off offset, size_t len,
 	    void *dest);
 	int (*seg_read_string)(elf_file_t, Elf_Off offset, size_t len,
 	    char *dest);
 	int (*seg_read_entry)(elf_file_t ef, Elf_Off offset, size_t len,
 	    void**ptr);
 	int (*seg_read_entry_rel)(elf_file_t ef, Elf_Off offset, size_t len,
 	    void**ptr);
 	Elf_Addr (*symaddr)(elf_file_t ef, Elf_Size symidx);
 	int (*lookup_set)(elf_file_t ef, const char *name, long *startp,
 	    long *stopp, long *countp);
 	int (*lookup_symbol)(elf_file_t ef, const char* name, Elf_Sym** sym);
 };
 
 struct elf_file {
 	elf_file_t ef_ef;
 	struct elf_file_ops *ef_ops;
 };
 
 __BEGIN_DECLS
 int ef_open(const char *filename, struct elf_file *ef, int verbose);
 int ef_obj_open(const char *filename, struct elf_file *ef, int verbose);
 int ef_reloc(struct elf_file *ef, const void *reldata, int reltype,
     Elf_Off relbase, Elf_Off dataoff, size_t len, void *dest);
 __END_DECLS
 
 #endif /* _EF_H_*/