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>

4 files changed, 26 insertions, 54 deletions

diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
index a032d3a..dd2dd23 100644
--- a/lib/efi_loader/efi_bootmgr.c
+++ b/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,
-					  bootefi_image_path);
+		file_path = efi_dp_concat(bootefi_device_path,
+					  bootefi_image_path, false);
 		msg_path = bootefi_image_path;
 		log_debug("Loaded from disk\n");
 	}
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index c579d89..1951291 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/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;
diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
index 8dbd810..500fa10 100644
--- a/lib/efi_loader/efi_device_path.c
+++ b/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.
- *				    Concatenated device path will be separated
- *				    by a sub-type 0xff end node
+ * efi_dp_concat() - Concatenate two device paths and add and terminate them
+ *                   with an end node.
  *
- * @dp1:	First device path
- * @dp2:	Second device path
- * @concat:	If true the two device paths will be concatenated and separated
- *		by an end of entrire device path sub-type 0xff end node.
- *		If true the second device path will be appended to the first and
- *		terminated by an end node
+ * @dp1:	    First device path
+ * @dp2:	    Second device path
+ * @split_end_node: If true the two device paths will be concatenated and
+ *                  separated by an end node (DEVICE_PATH_SUB_TYPE_END).
+ *		    If false the second device path will be concatenated to the
+ *		    first one as-is.
  *
  * Return:
  * concatenated device path or NULL. Caller must free the returned value
  */
-static struct
-efi_device_path *efi_dp_append_or_concatenate(const struct efi_device_path *dp1,
-					      const struct efi_device_path *dp2,
-					      bool concat)
+struct
+efi_device_path *efi_dp_concat(const struct efi_device_path *dp1,
+			       const struct efi_device_path *dp2,
+			       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)
 {
diff --git a/lib/efi_loader/efi_device_path_utilities.c b/lib/efi_loader/efi_device_path_utilities.c
index 844d8ac..c95dbfa 100644
--- a/lib/efi_loader/efi_device_path_utilities.c
+++ b/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));
 }
 
 /*