[PATCH 1/3] efi_loader: print boot device and file path in helloworld

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

Let helloworld.efi print the device path of the boot device and the file
path as provided by the loaded image protocol.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
 lib/efi_loader/helloworld.c | 167 +++++++++++++++++++++++++++++-------
 1 file changed, 137 insertions(+), 30 deletions(-)

diff --git a/lib/efi_loader/helloworld.c b/lib/efi_loader/helloworld.c
index 9ae2ee3389..5c8b7a96f9 100644
--- a/lib/efi_loader/helloworld.c
+++ b/lib/efi_loader/helloworld.c
@@ -1,43 +1,41 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
- * EFI hello world
+ * Hello world EFI application
  *
- * Copyright (c) 2016 Google, Inc
- * Written by Simon Glass <sjg@chromium.org>
+ * Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
  *
- * This program demonstrates calling a boottime service.
- * It writes a greeting and the load options to the console.
+ * This test program is used to test the invocation of an EFI application.
+ * It writes
+ *
+ * * a greeting
+ * * the firmware's UEFI version
+ * * the installed configuration tables
+ * * the boot device's device path and the file path
+ *
+ * to the console.
  */

-#include <common.h>
 #include <efi_api.h>

 static const efi_guid_t loaded_image_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
+static const efi_guid_t device_path_to_text_protocol_guid =
+	EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID;
+static const efi_guid_t device_path_guid = EFI_DEVICE_PATH_PROTOCOL_GUID;
 static const efi_guid_t fdt_guid = EFI_FDT_GUID;
 static const efi_guid_t acpi_guid = EFI_ACPI_TABLE_GUID;
 static const efi_guid_t smbios_guid = SMBIOS_TABLE_GUID;

+static struct efi_system_table *systable;
+static struct efi_boot_services *boottime;
+static struct efi_simple_text_output_protocol *con_out;
+
 /**
- * efi_main() - entry point of the EFI application.
- *
- * @handle:	handle of the loaded image
- * @systable:	system table
- * @return:	status code
+ * print_uefi_revision() - print UEFI revision number
  */
-efi_status_t EFIAPI efi_main(efi_handle_t handle,
-			     struct efi_system_table *systable)
+static void print_uefi_revision(void)
 {
-	struct efi_simple_text_output_protocol *con_out = systable->con_out;
-	struct efi_boot_services *boottime = systable->boottime;
-	struct efi_loaded_image *loaded_image;
-	efi_status_t ret;
-	efi_uintn_t i;
 	u16 rev[] = L"0.0.0";

-	/* UEFI requires CR LF */
-	con_out->output_string(con_out, L"Hello, world!\r\n");
-
-	/* Print the revision number */
 	rev[0] = (systable->hdr.revision >> 16) + '0';
 	rev[4] = systable->hdr.revision & 0xffff;
 	for (; rev[4] >= 10;) {
@@ -53,15 +51,15 @@ efi_status_t EFIAPI efi_main(efi_handle_t handle,
 	con_out->output_string(con_out, L"Running on UEFI ");
 	con_out->output_string(con_out, rev);
 	con_out->output_string(con_out, L"\r\n");
+}
+
+/**
+ * print_config_tables() - print configuration tables
+ */
+static void print_config_tables(void)
+{
+	efi_uintn_t i;

-	/* Get the loaded image protocol */
-	ret = boottime->handle_protocol(handle, &loaded_image_guid,
-					(void **)&loaded_image);
-	if (ret != EFI_SUCCESS) {
-		con_out->output_string
-			(con_out, L"Cannot open loaded image protocol\r\n");
-		goto out;
-	}
 	/* Find configuration tables */
 	for (i = 0; i < systable->nr_tables; ++i) {
 		if (!memcmp(&systable->tables[i].guid, &fdt_guid,
@@ -77,6 +75,16 @@ efi_status_t EFIAPI efi_main(efi_handle_t handle,
 			con_out->output_string
 					(con_out, L"Have SMBIOS table\r\n");
 	}
+}
+
+/**
+ * print_load_options() - print load options
+ *
+ * @systable:	system table
+ * @con_out:	simple text output protocol
+ */
+void print_load_options(struct efi_loaded_image *loaded_image)
+{
 	/* Output the load options */
 	con_out->output_string(con_out, L"Load options: ");
 	if (loaded_image->load_options_size && loaded_image->load_options)
@@ -85,6 +93,105 @@ efi_status_t EFIAPI efi_main(efi_handle_t handle,
 	else
 		con_out->output_string(con_out, L"<none>");
 	con_out->output_string(con_out, L"\r\n");
+}
+
+/**
+ * print_device_path() - print device path
+ *
+ * @device_path:	device path to print
+ * @dp2txt:		device path to text protocol
+ */
+efi_status_t print_device_path(struct efi_device_path *device_path,
+			       struct efi_device_path_to_text_protocol *dp2txt)
+{
+	u16 *string;
+	efi_status_t ret;
+
+	if (!device_path) {
+		con_out->output_string(con_out, L"<none>\r\n");
+		return EFI_SUCCESS;
+	}
+
+	string = dp2txt->convert_device_path_to_text(device_path, true, false);
+	if (!string) {
+		con_out->output_string
+			(con_out, L"Cannot convert device path to text\r\n");
+		return EFI_OUT_OF_RESOURCES;
+	}
+	con_out->output_string(con_out, string);
+	con_out->output_string(con_out, L"\r\n");
+	ret = boottime->free_pool(string);
+	if (ret != EFI_SUCCESS) {
+		con_out->output_string(con_out, L"Cannot free pool memory\r\n");
+		return ret;
+	}
+	return EFI_SUCCESS;
+}
+
+/**
+ * efi_main() - entry point of the EFI application.
+ *
+ * @handle:	handle of the loaded image
+ * @systab:	system table
+ * @return:	status code
+ */
+efi_status_t EFIAPI efi_main(efi_handle_t handle,
+			     struct efi_system_table *systab)
+{
+	struct efi_loaded_image *loaded_image;
+	struct efi_device_path_to_text_protocol *device_path_to_text;
+	struct efi_device_path *device_path;
+	efi_status_t ret;
+
+	systable = systab;
+	boottime = systable->boottime;
+	con_out = systable->con_out;
+
+	/* UEFI requires CR LF */
+	con_out->output_string(con_out, L"Hello, world!\r\n");
+
+	print_uefi_revision();
+	print_config_tables();
+
+	/* Get the loaded image protocol */
+	ret = boottime->handle_protocol(handle, &loaded_image_guid,
+					(void **)&loaded_image);
+	if (ret != EFI_SUCCESS) {
+		con_out->output_string
+			(con_out, L"Cannot open loaded image protocol\r\n");
+		goto out;
+	}
+	print_load_options(loaded_image);
+
+	/* Get the device path to text protocol */
+	ret = boottime->locate_protocol(&device_path_to_text_protocol_guid,
+					NULL, (void **)&device_path_to_text);
+	if (ret != EFI_SUCCESS) {
+		con_out->output_string
+			(con_out, L"Cannot open device path to text protocol\r\n");
+		goto out;
+	}
+	if (!loaded_image->device_handle) {
+		con_out->output_string
+			(con_out, L"Missing device handle\r\n");
+		goto out;
+	}
+	ret = boottime->handle_protocol(loaded_image->device_handle,
+					&device_path_guid,
+					(void **)&device_path);
+	if (ret != EFI_SUCCESS) {
+		con_out->output_string
+			(con_out, L"Missing devide path for device handle\r\n");
+		goto out;
+	}
+	con_out->output_string(con_out, L"Boot device: ");
+	ret = print_device_path(device_path, device_path_to_text);
+	if (ret != EFI_SUCCESS)
+		goto out;
+	con_out->output_string(con_out, L"File path: ");
+	ret = print_device_path(loaded_image->file_path, device_path_to_text);
+	if (ret != EFI_SUCCESS)
+		goto out;

 out:
 	boottime->exit(handle, ret, 0, NULL);
--
2.29.2