[PATCH v3 2/2] efi_loader: provide tool to dump SMBIOS table
Heinrich Schuchardt
heinrich.schuchardt at canonical.com
Wed Jan 3 09:07:21 CET 2024
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
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