efi_loader: Clean up efi_dp_append and efi_dp_concat

Looking back at the initrd storing functionality, we introduced three
functions, efi_dp_append_or_concatenate(), efi_dp_append/concat(). In
hindsight we could have simplified that by a lot. First of all none of
the functions append anything. They all allocate a new device path and
concatenate the contents of two device paths in one. A boolean parameter
controls the final device path -- if that's true an end node is injected
between the two device paths.

So let's rewrite this and make it a bit easier to read. Get rid of
efi_dp_append(), efi_dp_concat() and rename
efi_dp_append_or_concatenate() to efi_dp_concat(). This is far more
intuitive and the only adjustment that is needed is an extra boolean
argument on all callsites.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

cmd/eficonfig.c

@@ -531,7 +531,7 @@ struct efi_device_path *eficonfig_create_device_path(struct efi_device_path *dp_
 	dp = efi_dp_shorten(dp_volume);
 	if (!dp)
 		dp = dp_volume;
-	dp = efi_dp_append(dp, &fp->dp);
+	dp = efi_dp_concat(dp, &fp->dp, false);
 	free(buf);
 
 	return dp;
@@ -1484,7 +1484,8 @@ static efi_status_t eficonfig_edit_boot_option(u16 *varname, struct eficonfig_bo
 			ret = EFI_OUT_OF_RESOURCES;
 			goto out;
 		}
-		initrd_dp = efi_dp_append((const struct efi_device_path *)&id_dp, dp);
+		initrd_dp = efi_dp_concat((const struct efi_device_path *)&id_dp,
+					  dp, false);
 		efi_free_pool(dp);
 	}
 
@@ -1495,7 +1496,7 @@ static efi_status_t eficonfig_edit_boot_option(u16 *varname, struct eficonfig_bo
 	}
 	final_dp_size = efi_dp_size(dp) + sizeof(END);
 	if (initrd_dp) {
-		final_dp = efi_dp_concat(dp, initrd_dp);
+		final_dp = efi_dp_concat(dp, initrd_dp, true);
 		final_dp_size += efi_dp_size(initrd_dp) + sizeof(END);
 	} else {
 		final_dp = efi_dp_dup(dp);

cmd/efidebug.c

@@ -699,8 +699,8 @@ struct efi_device_path *create_initrd_dp(const char *dev, const char *part,
 	if (!short_fp)
 		short_fp = tmp_fp;
 
-	initrd_dp = efi_dp_append((const struct efi_device_path *)&id_dp,
+	initrd_dp = efi_dp_concat((const struct efi_device_path *)&id_dp,
-				  short_fp);
+				  short_fp, false);
 
 out:
 	efi_free_pool(tmp_dp);
@@ -916,7 +916,7 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
 		goto out;
 	}
 
-	final_fp = efi_dp_concat(file_path, initrd_dp);
+	final_fp = efi_dp_concat(file_path, initrd_dp, true);
 	if (!final_fp) {
 		printf("Cannot create final device path\n");
 		r = CMD_RET_FAILURE;

include/efi_loader.h

@@ -819,8 +819,6 @@ efi_uintn_t efi_dp_instance_size(const struct efi_device_path *dp);
 /* size of multi-instance device path excluding end node */
 efi_uintn_t efi_dp_size(const struct efi_device_path *dp);
 struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp);
-struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
-				      const struct efi_device_path *dp2);
 struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
 					   const struct efi_device_path *node);
 /* Create a device path node of given type, sub-type, length */
@@ -937,7 +935,8 @@ struct efi_load_option {
 struct efi_device_path *efi_dp_from_lo(struct efi_load_option *lo,
 				       const efi_guid_t *guid);
 struct efi_device_path *efi_dp_concat(const struct efi_device_path *dp1,
-				      const struct efi_device_path *dp2);
+				      const struct efi_device_path *dp2,
+				      bool split_end_node);
 struct efi_device_path *search_gpt_dp_node(struct efi_device_path *device_path);
 efi_status_t efi_deserialize_load_option(struct efi_load_option *lo, u8 *data,
 					 efi_uintn_t *size);

lib/efi_loader/efi_bootmgr.c

@@ -143,7 +143,7 @@ static efi_status_t try_load_from_file_path(efi_handle_t *fs_handles,
 		if (!dp)
 			continue;
 
-		dp = efi_dp_append(dp, fp);
+		dp = efi_dp_concat(dp, fp, false);
 		if (!dp)
 			continue;
 
@@ -1579,8 +1579,8 @@ efi_status_t efi_run_image(void *source_buffer, efi_uintn_t source_size)
 			goto out;
 		msg_path = file_path;
 	} else {
-		file_path = efi_dp_append(bootefi_device_path,
+		file_path = efi_dp_concat(bootefi_device_path,
-					  bootefi_image_path);
+					  bootefi_image_path, false);
 		msg_path = bootefi_image_path;
 		log_debug("Loaded from disk\n");
 	}

lib/efi_loader/efi_boottime.c

@@ -1816,7 +1816,7 @@ efi_status_t efi_setup_loaded_image(struct efi_device_path *device_path,
 	if (device_path) {
 		info->device_handle = efi_dp_find_obj(device_path, NULL, NULL);
 
-		dp = efi_dp_append(device_path, file_path);
+		dp = efi_dp_concat(device_path, file_path, false);
 		if (!dp) {
 			ret = EFI_OUT_OF_RESOURCES;
 			goto failure;

lib/efi_loader/efi_device_path.c

@@ -271,30 +271,27 @@ struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp)
 }
 
 /**
- * efi_dp_append_or_concatenate() - Append or concatenate two device paths.
+ * efi_dp_concat() - Concatenate two device paths and add and terminate them
- *				    Concatenated device path will be separated
+ *                   with an end node.
- *				    by a sub-type 0xff end node
  *
  * @dp1:	    First device path
  * @dp2:	    Second device path
- * @concat:	If true the two device paths will be concatenated and separated
+ * @split_end_node: If true the two device paths will be concatenated and
- *		by an end of entrire device path sub-type 0xff end node.
+ *                  separated by an end node (DEVICE_PATH_SUB_TYPE_END).
- *		If true the second device path will be appended to the first and
+ *		    If false the second device path will be concatenated to the
- *		terminated by an end node
+ *		    first one as-is.
  *
  * Return:
  * concatenated device path or NULL. Caller must free the returned value
  */
-static struct
+struct
-efi_device_path *efi_dp_append_or_concatenate(const struct efi_device_path *dp1,
+efi_device_path *efi_dp_concat(const struct efi_device_path *dp1,
 			       const struct efi_device_path *dp2,
-					      bool concat)
+			       bool split_end_node)
 {
 	struct efi_device_path *ret;
-	size_t end_size = sizeof(END);
+	size_t end_size;
 
-	if (concat)
-		end_size = 2 * sizeof(END);
 	if (!dp1 && !dp2) {
 		/* return an end node */
 		ret = efi_dp_dup(&END);
@@ -306,14 +303,20 @@ efi_device_path *efi_dp_append_or_concatenate(const struct efi_device_path *dp1,
 		/* both dp1 and dp2 are non-null */
 		unsigned sz1 = efi_dp_size(dp1);
 		unsigned sz2 = efi_dp_size(dp2);
-		void *p = efi_alloc(sz1 + sz2 + end_size);
+		void *p;
+
+		if (split_end_node)
+			end_size = 2 * sizeof(END);
+		else
+			end_size = sizeof(END);
+		p = efi_alloc(sz1 + sz2 + end_size);
 		if (!p)
 			return NULL;
 		ret = p;
 		memcpy(p, dp1, sz1);
 		p += sz1;
 
-		if (concat) {
+		if (split_end_node) {
 			memcpy(p, &END, sizeof(END));
 			p += sizeof(END);
 		}
@@ -327,37 +330,6 @@ efi_device_path *efi_dp_append_or_concatenate(const struct efi_device_path *dp1,
 	return ret;
 }
 
-/**
- * efi_dp_append() - Append a device to an existing device path.
- *
- * @dp1:	First device path
- * @dp2:	Second device path
- *
- * Return:
- * concatenated device path or NULL. Caller must free the returned value
- */
-struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
-				      const struct efi_device_path *dp2)
-{
-	return efi_dp_append_or_concatenate(dp1, dp2, false);
-}
-
-/**
- * efi_dp_concat() - Concatenate 2 device paths. The final device path will
- *                   contain two device paths separated by and end node (0xff).
- *
- * @dp1:	First device path
- * @dp2:	Second device path
- *
- * Return:
- * concatenated device path or NULL. Caller must free the returned value
- */
-struct efi_device_path *efi_dp_concat(const struct efi_device_path *dp1,
-				      const struct efi_device_path *dp2)
-{
-	return efi_dp_append_or_concatenate(dp1, dp2, true);
-}
-
 struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
 					   const struct efi_device_path *node)
 {

lib/efi_loader/efi_device_path_utilities.c

@@ -76,7 +76,7 @@ static struct efi_device_path * EFIAPI append_device_path(
 	const struct efi_device_path *src2)
 {
 	EFI_ENTRY("%pD, %pD", src1, src2);
-	return EFI_EXIT(efi_dp_append(src1, src2));
+	return EFI_EXIT(efi_dp_concat(src1, src2, false));
 }
 
 /*