repart: Do offline encryption instead of online

Offline encryption can be done without mounting the luks device. For
now we still use loop devices to split out the partition we want to
write to but in a later commit we'll replace this with a regular file.

For offline encryption, we need to keep 2x the luks header size space
free at the end of the partition, so this means our encrypted partitions
will be 16M larger than before.

src/shared/cryptsetup-util.c

@@ -49,6 +49,18 @@ int (*sym_crypt_token_max)(const char *type);
 #endif
 crypt_token_info (*sym_crypt_token_status)(struct crypt_device *cd, int token, const char **type);
 int (*sym_crypt_volume_key_get)(struct crypt_device *cd, int keyslot, char *volume_key, size_t *volume_key_size, const char *passphrase, size_t passphrase_size);
+#if HAVE_CRYPT_REENCRYPT_INIT_BY_PASSPHRASE
+int (*sym_crypt_reencrypt_init_by_passphrase)(struct crypt_device *cd, const char *name, const char *passphrase, size_t passphrase_size, int keyslot_old, int keyslot_new, const char *cipher, const char *cipher_mode, const struct crypt_params_reencrypt *params);
+#endif
+#if HAVE_CRYPT_REENCRYPT
+int (*sym_crypt_reencrypt)(struct crypt_device *cd, int (*progress)(uint64_t size, uint64_t offset, void *usrptr));
+#endif
+int (*sym_crypt_metadata_locking)(struct crypt_device *cd, int enable);
+#if HAVE_CRYPT_SET_DATA_OFFSET
+int (*sym_crypt_set_data_offset)(struct crypt_device *cd, uint64_t data_offset);
+#endif
+int (*sym_crypt_header_restore)(struct crypt_device *cd, const char *requested_type, const char *backup_file);
+int (*sym_crypt_volume_key_keyring)(struct crypt_device *cd, int enable);
 
 static void cryptsetup_log_glue(int level, const char *msg, void *usrptr) {
 
@@ -234,7 +246,19 @@ int dlopen_cryptsetup(void) {
                         DLSYM_ARG(crypt_token_max),
 #endif
                         DLSYM_ARG(crypt_token_status),
-                        DLSYM_ARG(crypt_volume_key_get));
+                        DLSYM_ARG(crypt_volume_key_get),
+#if HAVE_CRYPT_REENCRYPT_INIT_BY_PASSPHRASE
+                        DLSYM_ARG(crypt_reencrypt_init_by_passphrase),
+#endif
+#if HAVE_CRYPT_REENCRYPT
+                        DLSYM_ARG(crypt_reencrypt),
+#endif
+                        DLSYM_ARG(crypt_metadata_locking),
+#if HAVE_CRYPT_SET_DATA_OFFSET
+                        DLSYM_ARG(crypt_set_data_offset),
+#endif
+                        DLSYM_ARG(crypt_header_restore),
+                        DLSYM_ARG(crypt_volume_key_keyring));
         if (r <= 0)
                 return r;