diff --git a/contrib/elftoolchain/elfcopy/binary.c b/contrib/elftoolchain/elfcopy/binary.c
index 621362345f11..bc5f9fd8d041 100644
--- a/contrib/elftoolchain/elfcopy/binary.c
+++ b/contrib/elftoolchain/elfcopy/binary.c
@@ -37,16 +37,6 @@
 
 ELFTC_VCSID("$Id: binary.c 3174 2015-03-27 17:13:41Z emaste $");
 
-static int
-basename_length(const char *filename)
-{
-	char *p;
-
-	if ((p = strchr(filename, '.')) != NULL)
-		return (p - filename);
-	return (strlen(filename));
-}
-
 /*
  * Convert ELF object to `binary'. Sections with SHF_ALLOC flag set
  * are copied to the result binary. The relative offsets for each section
@@ -150,6 +140,7 @@ create_elf_from_binary(struct elfcopy *ecp, int ifd, const char *ifn)
 	GElf_Shdr sh;
 	void *content;
 	uint64_t off, data_start, data_end, data_size;
+	char *sym_basename, *p;
 
 	/* Reset internal section list. */
 	if (!TAILQ_EMPTY(&ecp->v_sec))
@@ -220,9 +211,13 @@ create_elf_from_binary(struct elfcopy *ecp, int ifd, const char *ifn)
 	/* Count in .symtab and .strtab section headers.  */
 	shtab->sz += gelf_fsize(ecp->eout, ELF_T_SHDR, 2, EV_CURRENT);
 
+	if ((sym_basename = strdup(ifn)) == NULL)
+		err(1, "strdup");
+	p = sym_basename;
+	while ((p = strchr(p, '.')) != NULL)
+		*p++ = '_';
 #define	_GEN_SYMNAME(S) do {						\
-	snprintf(name, sizeof(name), "%s%.*s%s", "_binary_",		\
-	    basename_length(ifn), ifn, S);				\
+	snprintf(name, sizeof(name), "%s%s%s", "_binary_", sym_basename, S); \
 } while (0)
 
 	/*
@@ -244,6 +239,7 @@ create_elf_from_binary(struct elfcopy *ecp, int ifd, const char *ifn)
 	finalize_external_symtab(ecp);
 	create_symtab_data(ecp);
 #undef	_GEN_SYMNAME
+	free(sym_basename);
 
 	/*
 	 * Write the underlying ehdr. Note that it should be called