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+/*
+ * Portability wrapper around krb5.h.
+ *
+ * This header includes krb5.h and then adjusts for various portability
+ * issues, primarily between MIT Kerberos and Heimdal, so that code can be
+ * written to a consistent API.
+ *
+ * Unfortunately, due to the nature of the differences between MIT Kerberos
+ * and Heimdal, it's not possible to write code to either one of the APIs and
+ * adjust for the other one.  In general, this header tries to make available
+ * the Heimdal API and fix it for MIT Kerberos, but there are places where MIT
+ * Kerberos requires a more specific call.  For those cases, it provides the
+ * most specific interface.
+ *
+ * For example, MIT Kerberos has krb5_free_unparsed_name() whereas Heimdal
+ * prefers the generic krb5_xfree().  In this case, this header provides
+ * krb5_free_unparsed_name() for both APIs since it's the most specific call.
+ *
+ * Written by Russ Allbery <rra@stanford.edu>
+ * This work is hereby placed in the public domain by its author.
+ */
+
+#ifndef PORTABLE_KRB5_H
+#define PORTABLE_KRB5_H 1
+
+#include <config.h>
+#include <portable/macros.h>
+
+#include <krb5.h>
+
+BEGIN_DECLS
+
+/* Default to a hidden visibility for all portability functions. */
+#pragma GCC visibility push(hidden)
+
+/*
+ * krb5_{get,free}_error_message are the preferred APIs for both current MIT
+ * and current Heimdal, but there are tons of older APIs we may have to fall
+ * back on for earlier versions.
+ *
+ * This function should be called immediately after the corresponding error
+ * without any intervening Kerberos calls.  Otherwise, the correct error
+ * message and supporting information may not be returned.
+ */
+#ifndef HAVE_KRB5_GET_ERROR_MESSAGE
+const char *krb5_get_error_message(krb5_context, krb5_error_code);
+#endif
+#ifndef HAVE_KRB5_FREE_ERROR_MESSAGE
+void krb5_free_error_message(krb5_context, const char *);
+#endif
+
+/*
+ * Both current MIT and current Heimdal prefer _opt_alloc, but older versions
+ * of both require allocating your own struct and calling _opt_init.
+ */
+#ifndef HAVE_KRB5_GET_INIT_CREDS_OPT_ALLOC
+krb5_error_code krb5_get_init_creds_opt_alloc(krb5_context,
+                                              krb5_get_init_creds_opt **);
+#endif
+
+/* Heimdal-specific. */
+#ifndef HAVE_KRB5_GET_INIT_CREDS_OPT_SET_DEFAULT_FLAGS
+#define krb5_get_init_creds_opt_set_default_flags(c, p, r, o) /* empty */
+#endif
+
+/* Heimdal: krb5_kt_free_entry, MIT: krb5_free_keytab_entry_contents. */
+#ifndef HAVE_KRB5_KT_FREE_ENTRY
+# define krb5_kt_free_entry(c, e) krb5_free_keytab_entry_contents((c), (e))
+#endif
+
+/* Undo default visibility change. */
+#pragma GCC visibility pop
+
+#endif /* !PORTABLE_KRB5_H */