Prioritize volumes on boot media

This ensures that kernels are preferably loaded from the boot medium in
case there are multiple partitions with identical label names. For that
purpose, move all volumes on the boot medium to the front of the list.

As we are potentially reordering the list while building it, we need to
postpone its printing to the end when it is fully constructed.

Signed-off-by: Jan Kiszka <[email protected]>

utils.c

@@ -108,7 +108,7 @@ EFI_STATUS get_volumes(VOLUME_DESC **volumes, UINTN *count)
 	EFI_HANDLE *handles = NULL;
 	EFI_GUID sfspGuid = SIMPLE_FILE_SYSTEM_PROTOCOL;
 	UINTN handleCount = 0;
-	UINTN index, rootCount = 0;
+	UINTN index, rootCount = 0, bootCount = 0;
 
 	EFI_FILE_HANDLE tmp;
 
@@ -133,7 +133,6 @@ EFI_STATUS get_volumes(VOLUME_DESC **volumes, UINTN *count)
 
 	for (index = 0; index < handleCount; index++) {
 		EFI_FILE_IO_INTERFACE *fs = NULL;
-		CHAR16 *devpathstr;
 
 		status = BS->HandleProtocol(
 		    handles[index], &sfspGuid, (VOID **)&fs);
@@ -155,29 +154,38 @@ EFI_STATUS get_volumes(VOLUME_DESC **volumes, UINTN *count)
 			ERROR(L"Could not get device path for config partition, skipping.\n");
 			continue;
 		}
-		devpathstr = DevicePathToStr(devpath);
 
+		UINTN target = rootCount;
 		BOOLEAN onbootmedium = IsOnBootMedium(devpath);
-
-		(*volumes)[rootCount].root = tmp;
-		(*volumes)[rootCount].devpath = devpath;
-		(*volumes)[rootCount].onbootmedium = onbootmedium;
-		(*volumes)[rootCount].fslabel =
-		    get_volume_label((*volumes)[rootCount].root);
-		(*volumes)[rootCount].fscustomlabel =
-		    get_volume_custom_label((*volumes)[rootCount].root);
-		INFO(L"Volume %d: ", rootCount);
 		if (onbootmedium) {
-			INFO(L"(On boot medium) ");
+			CopyMem(&(*volumes)[bootCount + 1], &(*volumes)[bootCount],
+				(rootCount - bootCount) * sizeof(VOLUME_DESC));
+			target = bootCount++;
 		}
-		INFO(L"%s, LABEL=%s, CLABEL=%s\n",
-		      devpathstr, (*volumes)[rootCount].fslabel,
-		      (*volumes)[rootCount].fscustomlabel);
 
-		FreePool(devpathstr);
+		(*volumes)[target].root = tmp;
+		(*volumes)[target].devpath = devpath;
+		(*volumes)[target].onbootmedium = onbootmedium;
+		(*volumes)[target].fslabel =
+		    get_volume_label((*volumes)[target].root);
+		(*volumes)[target].fscustomlabel =
+		    get_volume_custom_label((*volumes)[target].root);
 
 		rootCount++;
 	}
+
+	for (index = 0; index < rootCount; index++) {
+		INFO(L"Volume %d: ", index);
+		if ((*volumes)[index].onbootmedium) {
+			INFO(L"(On boot medium) ");
+		}
+		CHAR16 *devpathstr = DevicePathToStr((*volumes)[index].devpath);
+		INFO(L"%s, LABEL=%s, CLABEL=%s\n",
+		      devpathstr, (*volumes)[index].fslabel,
+		      (*volumes)[index].fscustomlabel);
+		FreePool(devpathstr);
+	}
+
 	*count = rootCount;
 	return EFI_SUCCESS;
 }