source: bootcd/isolinux/syslinux-6.03/gnu-efi/gnu-efi-3.0/lib/smbios.c

/*++

Copyright (c) 2000  Intel Corporation

Module Name:

    Smbios.c
    
Abstract:

    Lib fucntions for SMBIOS. Used to get system serial number and GUID

Revision History

--*/

#include "lib.h"


EFI_STATUS
LibGetSmbiosSystemGuidAndSerialNumber (
    IN  EFI_GUID    *SystemGuid,
    OUT CHAR8       **SystemSerialNumber
    )
{
    EFI_STATUS                  Status;
    SMBIOS_STRUCTURE_TABLE      *SmbiosTable;
    SMBIOS_STRUCTURE_POINTER    Smbios;  
    SMBIOS_STRUCTURE_POINTER    SmbiosEnd;  
    UINT16                      Index;
    
    Status = LibGetSystemConfigurationTable(&SMBIOSTableGuid, (VOID**)&SmbiosTable);
    if (EFI_ERROR(Status)) {
        return EFI_NOT_FOUND;
    }

    Smbios.Hdr = (SMBIOS_HEADER *)SmbiosTable->TableAddress;
    SmbiosEnd.Raw = (UINT8 *)(SmbiosTable->TableAddress + SmbiosTable->TableLength);
    for (Index = 0; Index < SmbiosTable->TableLength ; Index++) {
        if (Smbios.Hdr->Type == 1) {
            if (Smbios.Hdr->Length < 0x19) {
                //
                // Older version did not support Guid and Serial number
                //
                continue;
            }

            //
            // SMBIOS tables are byte packed so we need to do a byte copy to
            //  prevend alignment faults on IA-64.
            
            CopyMem (SystemGuid, &Smbios.Type1->Uuid, sizeof(EFI_GUID));
            *SystemSerialNumber = LibGetSmbiosString(&Smbios, Smbios.Type1->SerialNumber);
            return EFI_SUCCESS;
        }

        //
        // Make Smbios point to the next record
        //
        LibGetSmbiosString (&Smbios, -1);

        if (Smbios.Raw >= SmbiosEnd.Raw) {
            //
            // SMBIOS 2.1 incorrectly stated the length of SmbiosTable as 0x1e. 
            //  given this we must double check against the lenght of
            /// the structure. My home PC has this bug.ruthard
            //
            return EFI_SUCCESS;
        }
    }

    return EFI_SUCCESS;
}

CHAR8*
LibGetSmbiosString (
    IN  SMBIOS_STRUCTURE_POINTER    *Smbios,
    IN  UINT16                      StringNumber
    )
/*++

    Return SMBIOS string given the string number.

    Arguments:
        Smbios - Pointer to SMBIOS structure
        StringNumber - String number to return. -1 is used to skip all strings and 
            point to the next SMBIOS structure.

    Returns:
        Pointer to string, or pointer to next SMBIOS strcuture if StringNumber == -1
--*/
{
    UINT16  Index;
    CHAR8   *String;

    //
    // Skip over formatted section
    //
    String = (CHAR8 *)(Smbios->Raw + Smbios->Hdr->Length);

    //
    // Look through unformated section
    //
    for (Index = 1; Index <= StringNumber; Index++) {
        if (StringNumber == Index) {
            return String;
        }

        //
        // Skip string
        //
        for (; *String != 0; String++);
        String++;

        if (*String == 0) {
            //
            // If double NULL then we are done.
            //  Retrun pointer to next structure in Smbios.
            //  if you pass in a -1 you will always get here
            //
            Smbios->Raw = (UINT8 *)++String;
            return NULL;        
        }
    }
    return NULL;        
}