crypt_gensalt
extern char *crypt_gensalt(const char *, const struct passwd *);
salt = crypt_gensalt(oldpw, &dummy);
salt = crypt_gensalt(spw->sp_pwdp, pw);
salt = crypt_gensalt(ldapbuf->passwd,
salt = crypt_gensalt(
if ((*salt = crypt_gensalt("$5", pw)) == NULL) {