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

[AKASHI Takahiro]

Heinrich,

On Tue, Jan 12, 2021 at 08:58:40PM +0100, Heinrich Schuchardt wrote:
> 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 at 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 at chromium.org>
> + * Copyright 2020, Heinrich Schuchardt <xypron.glpk at 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

If this kind of information is quite useful for users, why not add
that (printing) feature as an option of bootefi (or efidebug)?
I'm afraid that most users who are irritated as you said won't be able
to imagine such information be printed by helloworld app.

-Takahiro Akashi

> + *
> + * 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
>