[PATCH v3 2/2] efi_loader: provide tool to dump SMBIOS table
Ilias Apalodimas
ilias.apalodimas at linaro.org
Mon Jan 8 11:02:56 CET 2024
On Wed, 3 Jan 2024 at 10:07, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> An EFI binary smbiosdump.efi is provided that can be used to check the
> SMBIOS table for consistency and to dump it as a file.
>
> The tool provides the following commands:
>
> check
> Check the SMBIOS table for consistency.
>
> exit
> Leave the tool.
>
> help
> Show available commands.
>
> save
> Save the SMBIOS table to a file on the EFI system partition. The file
> can be further analyzed with the dmidecode command line tool::
>
> dmidecode --from-dump <filename>
>
> Specifying 'nocolor' as load option data suppresses colored output and
> clearing of the screen.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
> v3:
> rename the tool
> restructure the code
> handle NULL value in starts_with()
> v2:
> fix an incorrect variable usage when checking the result of memcmp
> ---
> lib/efi_loader/Makefile | 7 +
> lib/efi_loader/smbiosdump.c | 622 ++++++++++++++++++++++++++++++++++++
> 2 files changed, 629 insertions(+)
> create mode 100644 lib/efi_loader/smbiosdump.c
>
> diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
> index 24d33d5409..25060bbd95 100644
> --- a/lib/efi_loader/Makefile
> +++ b/lib/efi_loader/Makefile
> @@ -16,6 +16,8 @@ CFLAGS_boothart.o := $(CFLAGS_EFI) -Os -ffreestanding
> CFLAGS_REMOVE_boothart.o := $(CFLAGS_NON_EFI)
> CFLAGS_helloworld.o := $(CFLAGS_EFI) -Os -ffreestanding
> CFLAGS_REMOVE_helloworld.o := $(CFLAGS_NON_EFI)
> +CFLAGS_smbiosdump.o := $(CFLAGS_EFI) -Os -ffreestanding
> +CFLAGS_REMOVE_smbiosdump.o := $(CFLAGS_NON_EFI)
> CFLAGS_dtbdump.o := $(CFLAGS_EFI) -Os -ffreestanding
> CFLAGS_REMOVE_dtbdump.o := $(CFLAGS_NON_EFI)
> CFLAGS_initrddump.o := $(CFLAGS_EFI) -Os -ffreestanding
> @@ -31,6 +33,11 @@ always += helloworld.efi
> targets += helloworld.o
> endif
>
> +ifneq ($(CONFIG_GENERATE_SMBIOS_TABLE),)
> +always += smbiosdump.efi
> +targets += smbiosdump.o
> +endif
> +
> ifeq ($(CONFIG_GENERATE_ACPI_TABLE),)
> always += dtbdump.efi
> targets += dtbdump.o
> diff --git a/lib/efi_loader/smbiosdump.c b/lib/efi_loader/smbiosdump.c
> new file mode 100644
> index 0000000000..8a42794789
> --- /dev/null
> +++ b/lib/efi_loader/smbiosdump.c
> @@ -0,0 +1,622 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright 2023, Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> + *
> + * smbiosdump.efi saves the SMBIOS table as file.
> + *
> + * Specifying 'nocolor' as load option data suppresses colored output and
> + * clearing of the screen.
> + */
> +
> +#include <efi_api.h>
> +#include <part.h>
> +#include <smbios.h>
> +#include <string.h>
> +
> +#define BUFFER_SIZE 64
> +
> +static struct efi_simple_text_output_protocol *cerr;
> +static struct efi_simple_text_output_protocol *cout;
> +static struct efi_simple_text_input_protocol *cin;
> +static struct efi_boot_services *bs;
> +static efi_handle_t handle;
> +static struct efi_system_table *systable;
> +static const efi_guid_t smbios_guid = SMBIOS_TABLE_GUID;
> +static const efi_guid_t smbios3_guid = SMBIOS3_TABLE_GUID;
> +static const efi_guid_t loaded_image_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
> +static const efi_guid_t guid_simple_file_system_protocol =
> + EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
> +static const efi_guid_t efi_system_partition_guid = PARTITION_SYSTEM_GUID;
> +static bool nocolor;
> +
> +/**
> + * color() - set foreground color
> + *
> + * @color: foreground color
> + */
> +static void color(u8 color)
> +{
> + if (!nocolor)
> + cout->set_attribute(cout, color | EFI_BACKGROUND_BLACK);
> +}
> +
> +/**
> + * print() - print string
> + *
> + * @string: text
> + */
> +static void print(u16 *string)
> +{
> + cout->output_string(cout, string);
> +}
> +
> +/**
> + * cls() - clear screen
> + */
> +static void cls(void)
> +{
> + if (nocolor)
> + print(u"\r\n");
> + else
> + cout->clear_screen(cout);
> +}
> +
> +/**
> + * error() - print error string
> + *
> + * @string: error text
> + */
> +static void error(u16 *string)
> +{
> + color(EFI_LIGHTRED);
> + print(string);
> + color(EFI_LIGHTBLUE);
> +}
> +
> +/**
> + * efi_input_yn() - get answer to yes/no question
> + *
> + * Return:
> + * y or Y
> + * EFI_SUCCESS
> + * n or N
> + * EFI_ACCESS_DENIED
> + * ESC
> + * EFI_ABORTED
> + */
> +static efi_status_t efi_input_yn(void)
> +{
> + struct efi_input_key key = {0};
> + efi_uintn_t index;
> + efi_status_t ret;
> +
> + /* Drain the console input */
> + ret = cin->reset(cin, true);
> + for (;;) {
> + ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
> + if (ret != EFI_SUCCESS)
> + continue;
> + ret = cin->read_key_stroke(cin, &key);
> + if (ret != EFI_SUCCESS)
> + continue;
> + switch (key.scan_code) {
> + case 0x17: /* Escape */
> + return EFI_ABORTED;
> + default:
> + break;
> + }
> + /* Convert to lower case */
> + switch (key.unicode_char | 0x20) {
> + case 'y':
> + return EFI_SUCCESS;
> + case 'n':
> + return EFI_ACCESS_DENIED;
> + default:
> + break;
> + }
> + }
> +}
> +
> +/**
> + * efi_input() - read string from console
> + *
> + * @buffer: input buffer
> + * @buffer_size: buffer size
> + * Return: status code
> + */
> +static efi_status_t efi_input(u16 *buffer, efi_uintn_t buffer_size)
> +{
> + struct efi_input_key key = {0};
> + efi_uintn_t index;
> + efi_uintn_t pos = 0;
> + u16 outbuf[2] = u" ";
> + efi_status_t ret;
> +
> + /* Drain the console input */
> + ret = cin->reset(cin, true);
> + *buffer = 0;
> + for (;;) {
> + ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
> + if (ret != EFI_SUCCESS)
> + continue;
> + ret = cin->read_key_stroke(cin, &key);
> + if (ret != EFI_SUCCESS)
> + continue;
> + switch (key.scan_code) {
> + case 0x17: /* Escape */
> + print(u"\r\nAborted\r\n");
> + return EFI_ABORTED;
> + default:
> + break;
> + }
> + switch (key.unicode_char) {
> + case 0x08: /* Backspace */
> + if (pos) {
> + buffer[pos--] = 0;
> + print(u"\b \b");
> + }
> + break;
> + case 0x0a: /* Linefeed */
> + case 0x0d: /* Carriage return */
> + print(u"\r\n");
> + return EFI_SUCCESS;
> + default:
> + break;
> + }
> + /* Ignore surrogate codes */
> + if (key.unicode_char >= 0xD800 && key.unicode_char <= 0xDBFF)
> + continue;
> + if (key.unicode_char >= 0x20 &&
> + pos < buffer_size - 1) {
> + *outbuf = key.unicode_char;
> + buffer[pos++] = key.unicode_char;
> + buffer[pos] = 0;
> + print(outbuf);
> + }
> + }
> +}
> +
> +/**
> + * skip_whitespace() - skip over leading whitespace
> + *
> + * @pos: UTF-16 string
> + * Return: pointer to first non-whitespace
> + */
> +static u16 *skip_whitespace(u16 *pos)
> +{
> + for (; *pos && *pos <= 0x20; ++pos)
> + ;
> + return pos;
> +}
> +
> +/**
> + * starts_with() - check if @string starts with @keyword
> + *
> + * @string: string to search for keyword
> + * @keyword: keyword to be searched
> + * Return: true fi @string starts with the keyword
> + */
> +static bool starts_with(u16 *string, u16 *keyword)
> +{
> + if (!string || !keyword)
> + return NULL;
> +
> + for (; *keyword; ++string, ++keyword) {
> + if (*string != *keyword)
> + return false;
> + }
> + return true;
> +}
> +
> +/**
> + * open_file_system() - open simple file system protocol
> + *
> + * file_system: interface of the simple file system protocol
> + * Return: status code
> + */
> +static efi_status_t
> +open_file_system(struct efi_simple_file_system_protocol **file_system)
> +{
> + struct efi_loaded_image *loaded_image;
> + efi_status_t ret;
> + efi_handle_t *handle_buffer = NULL;
> + efi_uintn_t count;
> +
> + ret = bs->open_protocol(handle, &loaded_image_guid,
> + (void **)&loaded_image, NULL, NULL,
> + EFI_OPEN_PROTOCOL_GET_PROTOCOL);
> + if (ret != EFI_SUCCESS) {
> + error(u"Loaded image protocol not found\r\n");
> + return ret;
> + }
> +
> + /* Open the simple file system protocol on the same partition */
> + ret = bs->open_protocol(loaded_image->device_handle,
> + &guid_simple_file_system_protocol,
> + (void **)file_system, NULL, NULL,
> + EFI_OPEN_PROTOCOL_GET_PROTOCOL);
> + if (ret == EFI_SUCCESS)
> + return ret;
> +
> + /* Open the simple file system protocol on the UEFI system partition */
> + ret = bs->locate_handle_buffer(BY_PROTOCOL, &efi_system_partition_guid,
> + NULL, &count, &handle_buffer);
> + if (ret == EFI_SUCCESS && handle_buffer)
> + ret = bs->open_protocol(handle_buffer[0],
> + &guid_simple_file_system_protocol,
> + (void **)file_system, NULL, NULL,
> + EFI_OPEN_PROTOCOL_GET_PROTOCOL);
> + if (ret != EFI_SUCCESS)
> + error(u"Failed to open simple file system protocol\r\n");
> + if (handle)
> + bs->free_pool(handle_buffer);
> +
> + return ret;
> +}
> +
> +/**
> + * do_help() - print help
> + */
> +static void do_help(void)
> +{
> + error(u"check - check SMBIOS table\r\n");
> + error(u"save <file> - save SMBIOS table to file\r\n");
> + error(u"exit - exit the shell\r\n");
> +}
> +
> +/**
> + * get_config_table() - get configuration table
> + *
> + * @guid: GUID of the configuration table
> + * Return: pointer to configuration table or NULL
> + */
> +static void *get_config_table(const efi_guid_t *guid)
> +{
> + size_t i;
> +
> + for (i = 0; i < systable->nr_tables; ++i) {
> + if (!memcmp(guid, &systable->tables[i].guid, 16))
> + return systable->tables[i].table;
> + }
> +
> + return NULL;
> +}
> +
> +/**
> + * checksum() - calculate checksum
> + *
> + * @buf: buffer to checksum
> + * @len: length of buffer
> + * Return: checksum
> + */
> +u8 checksum(void *buf, int len)
> +{
> + u8 ret = 0;
> +
> + for (u8 *ptr = buf; len; --len, ++ptr)
> + ret -= *ptr;
> +
> + return ret;
> +}
> +
> +/**
> + * do_check() - check SMBIOS table
> + *
> + * Return: status code
> + */
> +efi_status_t do_check(void)
> +{
> + struct smbios3_entry *smbios3_anchor;
> + void *table, *table_end;
> + u32 len;
> +
> + smbios3_anchor = get_config_table(&smbios3_guid);
> + if (smbios3_anchor) {
> + int r;
> +
> + r = memcmp(smbios3_anchor->anchor, "_SM3_", 5);
> + if (r) {
> + error(u"Invalid anchor string\n");
> + return EFI_LOAD_ERROR;
> + }
> + print(u"Found SMBIOS 3 entry point\n");
> + if (smbios3_anchor->length != 0x18) {
> + error(u"Invalid anchor length\n");
> + return EFI_LOAD_ERROR;
> + }
> + if (checksum(smbios3_anchor, smbios3_anchor->length)) {
> + error(u"Invalid anchor checksum\n");
> + return EFI_LOAD_ERROR;
> + }
> + table = (void *)(uintptr_t)smbios3_anchor->struct_table_address;
> + len = smbios3_anchor->max_struct_size;
> + } else {
> + struct smbios_entry *smbios_anchor;
> + int r;
> +
> + smbios_anchor = get_config_table(&smbios_guid);
> + if (!smbios_anchor) {
> + error(u"No SMBIOS table\n");
> + return EFI_NOT_FOUND;
> + }
> + r = memcmp(smbios_anchor->anchor, "_SM_", 4);
> + if (r) {
> + error(u"Invalid anchor string\n");
> + return EFI_LOAD_ERROR;
> + }
> + print(u"Found SMBIOS 2.1 entry point\n");
> + if (smbios_anchor->length != 0x1f) {
> + error(u"Invalid anchor length\n");
> + return EFI_LOAD_ERROR;
> + }
> + if (checksum(smbios_anchor, smbios_anchor->length)) {
> + error(u"Invalid anchor checksum\n");
> + return EFI_LOAD_ERROR;
> + }
> + r = memcmp(smbios_anchor->intermediate_anchor, "_DMI_", 5);
> + if (r) {
> + error(u"Invalid intermediate anchor string\n");
> + return EFI_LOAD_ERROR;
> + }
> + if (checksum(&smbios_anchor->intermediate_anchor, 0xf)) {
> + error(u"Invalid intermediate anchor checksum\n");
> + return EFI_LOAD_ERROR;
> + }
> + table = (void *)(uintptr_t)smbios_anchor->struct_table_address;
> + len = smbios_anchor->struct_table_length;
> + }
> +
> + table_end = (void *)((u8 *)table + len);
> + for (struct smbios_header *pos = table; ;) {
> + u8 *str = (u8 *)pos + pos->length;
> +
> + if (!*str)
> + ++str;
> + while (*str) {
> + for (; *str; ++str) {
> + if ((void *)str >= table_end) {
> + error(u"Structure table length exceeded\n");
> + return EFI_LOAD_ERROR;
> + }
> + }
> + ++str;
> + }
> + ++str;
> + if ((void *)str > table_end) {
> + error(u"Structure table length exceeded\n");
> + return EFI_LOAD_ERROR;
> + }
> + if (pos->type == 0x7f) /* End of table */
> + break;
> + pos = (struct smbios_header *)str;
> + }
> +
> + return EFI_SUCCESS;
> +}
> +
> +/**
> + * save_file() - save file to EFI system partition
> + *
> + * @filename: file name
> + * @buf: buffer to write
> + * @size: size of the buffer
> + */
> +efi_status_t save_file(u16 *filename, void *buf, efi_uintn_t size)
> +{
> + efi_uintn_t ret;
> + struct efi_simple_file_system_protocol *file_system;
> + struct efi_file_handle *root, *file;
> +
> + ret = open_file_system(&file_system);
> + if (ret != EFI_SUCCESS)
> + return ret;
> +
> + /* Open volume */
> + ret = file_system->open_volume(file_system, &root);
> + if (ret != EFI_SUCCESS) {
> + error(u"Failed to open volume\r\n");
> + return ret;
> + }
> + /* Check if file already exists */
> + ret = root->open(root, &file, filename, EFI_FILE_MODE_READ, 0);
> + if (ret == EFI_SUCCESS) {
> + file->close(file);
> + print(u"Overwrite existing file (y/n)? ");
> + ret = efi_input_yn();
> + print(u"\r\n");
> + if (ret != EFI_SUCCESS) {
> + root->close(root);
> + error(u"Aborted by user\r\n");
> + bs->free_pool(buf);
> + return ret;
> + }
> + }
> +
> + /* Create file */
> + ret = root->open(root, &file, filename,
> + EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE |
> + EFI_FILE_MODE_CREATE, EFI_FILE_ARCHIVE);
> + if (ret == EFI_SUCCESS) {
> + /* Write file */
> + ret = file->write(file, &size, buf);
> + if (ret != EFI_SUCCESS)
> + error(u"Failed to write file\r\n");
> + file->close(file);
> + } else {
> + error(u"Failed to open file\r\n");
> + }
> + root->close(root);
> +
> + return ret;
> +}
> +
> +/**
> + * do_save() - save SMBIOS table
> + *
> + * @filename: file name
> + * Return: status code
> + */
> +static efi_status_t do_save(u16 *filename)
> +{
> + struct smbios3_entry *smbios3_anchor;
> + u8 *buf;
> + efi_uintn_t size;
> + efi_uintn_t ret;
> +
> + ret = do_check();
> + if (ret != EFI_SUCCESS)
> + return ret;
> +
> + smbios3_anchor = get_config_table(&smbios3_guid);
> + if (smbios3_anchor) {
> + size = 0x20 + smbios3_anchor->max_struct_size;
> + ret = bs->allocate_pool(EFI_LOADER_DATA, size, (void **)&buf);
> + if (ret != EFI_SUCCESS) {
> + error(u"Out of memory\n");
> + return ret;
> + }
> +
> + memset(buf, 0, size);
> + memcpy(buf, smbios3_anchor, smbios3_anchor->length);
> + memcpy(buf + 0x20,
> + (void *)(uintptr_t)smbios3_anchor->struct_table_address,
> + smbios3_anchor->max_struct_size);
> +
> + smbios3_anchor = (struct smbios3_entry *)buf;
> + smbios3_anchor->struct_table_address = 0x20;
> + smbios3_anchor->checksum +=
> + checksum(smbios3_anchor, smbios3_anchor->length);
> + } else {
> + struct smbios_entry *smbios_anchor;
> +
> + smbios_anchor = get_config_table(&smbios_guid);
> + if (!smbios_anchor) {
> + /* Should not be reached after successful do_check() */
> + error(u"No SMBIOS table\n");
> + return EFI_NOT_FOUND;
> + }
> +
> + size = 0x20 + smbios_anchor->struct_table_length;
> +
> + ret = bs->allocate_pool(EFI_LOADER_DATA, size, (void **)&buf);
> + if (ret != EFI_SUCCESS) {
> + error(u"Out of memory\n");
> + return ret;
> + }
> +
> + memset(buf, 0, size);
> + memcpy(buf, smbios_anchor, smbios_anchor->length);
> + memcpy(buf + 0x20,
> + (void *)(uintptr_t)smbios_anchor->struct_table_address,
> + smbios_anchor->struct_table_length);
> +
> + smbios_anchor = (struct smbios_entry *)buf;
> + smbios_anchor->struct_table_address = 0x20;
> + smbios_anchor->intermediate_checksum +=
> + checksum(&smbios_anchor->intermediate_anchor, 0xf);
> + smbios_anchor->checksum +=
> + checksum(smbios_anchor, smbios_anchor->length);
> + }
> +
> + filename = skip_whitespace(filename);
> +
> + ret = save_file(filename, buf, size);
> +
> + if (ret == EFI_SUCCESS) {
> + print(filename);
> + print(u" written\r\n");
> + }
> +
> + bs->free_pool(buf);
> +
> + return ret;
> +}
> +
> +/**
> + * get_load_options() - get load options
> + *
> + * Return: load options or NULL
> + */
> +static u16 *get_load_options(void)
> +{
> + efi_status_t ret;
> + struct efi_loaded_image *loaded_image;
> +
> + ret = bs->open_protocol(handle, &loaded_image_guid,
> + (void **)&loaded_image, NULL, NULL,
> + EFI_OPEN_PROTOCOL_GET_PROTOCOL);
> + if (ret != EFI_SUCCESS) {
> + error(u"Loaded image protocol not found\r\n");
> + return NULL;
> + }
> +
> + if (!loaded_image->load_options_size || !loaded_image->load_options)
> + return NULL;
> +
> + return loaded_image->load_options;
> +}
> +
> +/**
> + * command_loop - process user commands
> + */
> +static void command_loop(void)
> +{
> + for (;;) {
> + u16 command[BUFFER_SIZE];
> + u16 *pos;
> + efi_uintn_t ret;
> +
> + print(u"=> ");
> + ret = efi_input(command, sizeof(command));
> + if (ret == EFI_ABORTED)
> + break;
> + pos = skip_whitespace(command);
> + if (starts_with(pos, u"exit")) {
> + break;
> + } else if (starts_with(pos, u"check")) {
> + ret = do_check();
> + if (ret == EFI_SUCCESS)
> + print(u"OK\n");
> + } else if (starts_with(pos, u"save ")) {
> + do_save(pos + 5);
> + } else {
> + do_help();
> + }
> + }
> +}
> +
> +/**
> + * 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 image_handle,
> + struct efi_system_table *systab)
> +{
> + u16 *load_options;
> +
> + handle = image_handle;
> + systable = systab;
> + cerr = systable->std_err;
> + cout = systable->con_out;
> + cin = systable->con_in;
> + bs = systable->boottime;
> + load_options = get_load_options();
> +
> + if (starts_with(load_options, u"nocolor"))
> + nocolor = true;
> +
> + color(EFI_WHITE);
> + cls();
> + print(u"DMI Dump\r\n========\r\n\r\n");
> + color(EFI_LIGHTBLUE);
> +
> + command_loop();
> +
> + color(EFI_LIGHTGRAY);
> + cls();
> +
> + return EFI_SUCCESS;
> +}
> --
> 2.43.0
>
Acked-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
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