smbios_settings.c

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/*
 * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <ipxe/settings.h>
#include <ipxe/init.h>
#include <ipxe/uuid.h>
#include <ipxe/smbios.h>

/** SMBIOS settings scope */
static const struct settings_scope smbios_settings_scope;

/**
 * Construct SMBIOS raw-data tag
 *
 * @v _type             SMBIOS structure type number
 * @v _structure        SMBIOS structure data type
 * @v _field            Field within SMBIOS structure data type
 * @ret tag             SMBIOS setting tag
 */
#define SMBIOS_RAW_TAG( _type, _structure, _field )             \
        ( ( (_type) << 16 ) |                                   \
          ( offsetof ( _structure, _field ) << 8 ) |            \
          ( sizeof ( ( ( _structure * ) 0 )->_field ) ) )

/**
 * Construct SMBIOS string tag
 *
 * @v _type             SMBIOS structure type number
 * @v _structure        SMBIOS structure data type
 * @v _field            Field within SMBIOS structure data type
 * @ret tag             SMBIOS setting tag
 */
#define SMBIOS_STRING_TAG( _type, _structure, _field )          \
        ( ( (_type) << 16 ) |                                   \
          ( offsetof ( _structure, _field ) << 8 ) )

/**
 * Check applicability of SMBIOS setting
 *
 * @v settings          Settings block
 * @v setting           Setting
 * @ret applies         Setting applies within this settings block
 */
static int smbios_applies ( struct settings *settings __unused,
                            const struct setting *setting ) {

        return ( setting->scope == &smbios_settings_scope );
}

/**
 * Fetch value of SMBIOS setting
 *
 * @v settings          Settings block, or NULL to search all blocks
 * @v setting           Setting to fetch
 * @v data              Buffer to fill with setting data
 * @v len               Length of buffer
 * @ret len             Length of setting data, or negative error
 */
static int smbios_fetch ( struct settings *settings, struct setting *setting,
                          void *data, size_t len ) {
        const struct smbios_header *structure;
        unsigned int tag_instance;
        unsigned int tag_type;
        unsigned int tag_offset;
        unsigned int tag_len;
        const void *src;
        size_t src_len;
        unsigned int string;
        union uuid uuid;

        /* Split tag into instance, type, offset and length */
        tag_instance = ( ( setting->tag >> 24 ) & 0xff );
        tag_type = ( ( setting->tag >> 16 ) & 0xff );
        tag_offset = ( ( setting->tag >> 8 ) & 0xff );
        tag_len = ( setting->tag & 0xff );

        /* Find SMBIOS structure */
        structure = smbios_structure ( tag_type, tag_instance );
        if ( ! structure )
                return -ENOENT;
        src = structure;
        src_len = structure->len;
        string = 0;

        /* A <length> of zero indicates that the byte at <offset>
         * contains a string index.  An <offset> of zero indicates
         * that the <length> contains a literal string index.
         *
         * Since the byte at offset zero can never contain a string
         * index, and a literal string index can never be zero, the
         * combination of both <length> and <offset> being zero
         * indicates that the entire structure is to be read.
         */
        if ( ( tag_len == 0 ) && ( tag_offset == 0 ) ) {
                /* Read whole structure */
        } else if ( ( tag_len == 0 ) || ( tag_offset == 0 ) ) {
                /* Read string */
                string = tag_len;
                if ( ( string == 0 ) && ( tag_offset < src_len ) )
                        string = *( ( uint8_t * ) src + tag_offset );
                src = smbios_string ( structure, string );
                if ( ! src )
                        return -ENOENT;
                assert ( string > 0 );
                src_len = strlen ( src );
        } else if ( tag_offset > src_len ) {
                /* Empty read beyond end of structure */
                src_len = 0;
        } else {
                /* Read partial structure */
                src += tag_offset;
                src_len -= tag_offset;
                if ( src_len > tag_len )
                        src_len = tag_len;
        }

        /* Mangle UUIDs if necessary.  iPXE treats UUIDs as being in
         * network byte order (big-endian).  SMBIOS specification
         * version 2.6 states that UUIDs are stored with little-endian
         * values in the first three fields; earlier versions did not
         * specify an endianness.  dmidecode assumes that the byte
         * order is little-endian if and only if the SMBIOS version is
         * 2.6 or higher; we match this behaviour.
         */
        if ( ( ( setting->type == &setting_type_uuid ) ||
               ( setting->type == &setting_type_guid ) ) &&
             ( src_len == sizeof ( uuid ) ) &&
             ( smbios_version() >= SMBIOS_VERSION ( 2, 6 ) ) ) {
                DBGC ( settings, "SMBIOS detected mangled UUID\n" );
                memcpy ( &uuid, src, sizeof ( uuid ) );
                uuid_mangle ( &uuid );
                src = &uuid;
        }

        /* Return data */
        if ( len > src_len )
                len = src_len;
        memcpy ( data, src, len );

        /* Set default type */
        if ( ! setting->type ) {
                setting->type = ( string ? &setting_type_string :
                                  &setting_type_hex );
        }

        return src_len;
}

/** SMBIOS settings operations */
static struct settings_operations smbios_settings_operations = {
        .applies = smbios_applies,
        .fetch = smbios_fetch,
};

/** SMBIOS settings */
static struct settings smbios_settings = {
        .refcnt = NULL,
        .siblings = LIST_HEAD_INIT ( smbios_settings.siblings ),
        .children = LIST_HEAD_INIT ( smbios_settings.children ),
        .op = &smbios_settings_operations,
        .default_scope = &smbios_settings_scope,
};

/** Initialise SMBIOS settings */
static void smbios_init ( void ) {
        struct settings *settings = &smbios_settings;
        int rc;

        if ( ( rc = register_settings ( settings, NULL, "smbios" ) ) != 0 ) {
                DBGC ( settings, "SMBIOS could not register settings: %s\n",
                       strerror ( rc ) );
                return;
        }
}

/** SMBIOS settings initialiser */
struct init_fn smbios_init_fn __init_fn ( INIT_NORMAL ) = {
        .name = "smbios",
        .initialise = smbios_init,
};

/** UUID setting obtained via SMBIOS */
const struct setting uuid_setting __setting ( SETTING_HOST, uuid ) = {
        .name = "uuid",
        .description = "UUID",
        .tag = SMBIOS_RAW_TAG ( SMBIOS_TYPE_SYSTEM_INFORMATION,
                                struct smbios_system_information, uuid ),
        .type = &setting_type_uuid,
        .scope = &smbios_settings_scope,
};

/** Manufacturer name setting */
const struct setting manufacturer_setting __setting ( SETTING_HOST_EXTRA,
                                                      manufacturer ) = {
        .name = "manufacturer",
        .description = "Manufacturer",
        .tag = SMBIOS_STRING_TAG ( SMBIOS_TYPE_SYSTEM_INFORMATION,
                                   struct smbios_system_information,
                                   manufacturer ),
        .type = &setting_type_string,
        .scope = &smbios_settings_scope,
};

/** Product name setting */
const struct setting product_setting __setting ( SETTING_HOST_EXTRA, product )={
        .name = "product",
        .description = "Product name",
        .tag = SMBIOS_STRING_TAG ( SMBIOS_TYPE_SYSTEM_INFORMATION,
                                   struct smbios_system_information,
                                   product ),
        .type = &setting_type_string,
        .scope = &smbios_settings_scope,
};

/** Serial number setting */
const struct setting serial_setting __setting ( SETTING_HOST_EXTRA, serial ) = {
        .name = "serial",
        .description = "Serial number",
        .tag = SMBIOS_STRING_TAG ( SMBIOS_TYPE_SYSTEM_INFORMATION,
                                   struct smbios_system_information,
                                   serial ),
        .type = &setting_type_string,
        .scope = &smbios_settings_scope,
};

/** Asset tag setting */
const struct setting asset_setting __setting ( SETTING_HOST_EXTRA, asset ) = {
        .name = "asset",
        .description = "Asset tag",
        .tag = SMBIOS_STRING_TAG ( SMBIOS_TYPE_ENCLOSURE_INFORMATION,
                                   struct smbios_enclosure_information,
                                   asset_tag ),
        .type = &setting_type_string,
        .scope = &smbios_settings_scope,
};

/** Board serial number setting (may differ from chassis serial number) */
const struct setting board_serial_setting __setting ( SETTING_HOST_EXTRA,
                                                      board-serial ) = {
        .name = "board-serial",
        .description = "Base board serial",
        .tag = SMBIOS_STRING_TAG ( SMBIOS_TYPE_BASE_BOARD_INFORMATION,
                                   struct smbios_base_board_information,
                                   serial ),
        .type = &setting_type_string,
        .scope = &smbios_settings_scope,
};