smbios.c File Reference

System Management BIOS. More...

#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <gpxe/uaccess.h>
#include <gpxe/smbios.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER)
static size_t	find_strings_terminator (size_t offset)
	Find SMBIOS strings terminator.
int	find_smbios_structure (unsigned int type, struct smbios_structure *structure)
	Find specific structure type within SMBIOS.
int	read_smbios_structure (struct smbios_structure *structure, void *data, size_t len)
	Copy SMBIOS structure.
int	read_smbios_string (struct smbios_structure *structure, unsigned int index, void *data, size_t len)
	Find indexed string within SMBIOS structure.
Variables
static struct smbios	smbios
	SMBIOS entry point descriptor.

---

Detailed Description

System Management BIOS.

Definition in file smbios.c.

---

Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

static size_t find_strings_terminator

(

size_t

offset

)

[static]

Find SMBIOS strings terminator.

Parameters:

offset

Offset to start of strings

Return values:

offset

Offset to strings terminator, or 0 if not found

Definition at line 45 of file smbios.c.

References smbios::address, copy_from_user(), and smbios::len.

Referenced by find_smbios_structure().

                                                        {
        size_t max_offset = ( smbios.len - 2 );
        uint16_t nulnul;

        for ( ; offset <= max_offset ; offset++ ) {
                copy_from_user ( &nulnul, smbios.address, offset, 2 );
                if ( nulnul == 0 )
                        return ( offset + 1 );
        }
        return 0;
}

int find_smbios_structure	(	unsigned int	type,
		struct smbios_structure *	structure
	)

Find specific structure type within SMBIOS.

Parameters:

	type	Structure type to search for
	structure	SMBIOS structure descriptor to fill in

Return values:

rc

Return status code

Definition at line 64 of file smbios.c.

References smbios::address, assert, copy_from_user(), smbios::count, DBG, ENOENT, find_smbios(), find_strings_terminator(), smbios_structure::header, smbios_header::len, smbios::len, smbios_structure::offset, offset, smbios_structure::strings_len, smbios_header::type, and UNULL.

Referenced by smbios_fetch().

                                                                 {
        unsigned int count = 0;
        size_t offset = 0;
        size_t strings_offset;
        size_t terminator_offset;
        int rc;

        /* Find SMBIOS */
        if ( ( smbios.address == UNULL ) &&
             ( ( rc = find_smbios ( &smbios ) ) != 0 ) )
                return rc;
        assert ( smbios.address != UNULL );

        /* Scan through list of structures */
        while ( ( ( offset + sizeof ( structure->header ) ) < smbios.len )
                && ( count < smbios.count ) ) {

                /* Read next SMBIOS structure header */
                copy_from_user ( &structure->header, smbios.address, offset,
                                 sizeof ( structure->header ) );

                /* Determine start and extent of strings block */
                strings_offset = ( offset + structure->header.len );
                if ( strings_offset > smbios.len ) {
                        DBG ( "SMBIOS structure at offset %zx with length "
                              "%x extends beyond SMBIOS\n", offset,
                              structure->header.len );
                        return -ENOENT;
                }
                terminator_offset = find_strings_terminator ( strings_offset );
                if ( ! terminator_offset ) {
                        DBG ( "SMBIOS structure at offset %zx has "
                              "unterminated strings section\n", offset );
                        return -ENOENT;
                }
                structure->strings_len = ( terminator_offset - strings_offset);

                DBG ( "SMBIOS structure at offset %zx has type %d, length %x, "
                      "strings length %zx\n", offset, structure->header.type,
                      structure->header.len, structure->strings_len );

                /* If this is the structure we want, return */
                if ( structure->header.type == type ) {
                        structure->offset = offset;
                        return 0;
                }

                /* Move to next SMBIOS structure */
                offset = ( terminator_offset + 1 );
                count++;
        }

        DBG ( "SMBIOS structure type %d not found\n", type );
        return -ENOENT;
}

int read_smbios_structure	(	struct smbios_structure *	structure,
		void *	data,
		size_t	len
	)

Copy SMBIOS structure.

Parameters:

	structure	SMBIOS structure descriptor
	data	Buffer to hold SMBIOS structure
	len	Length of buffer

Return values:

rc

Return status code

Definition at line 129 of file smbios.c.

References smbios::address, assert, copy_from_user(), smbios_structure::header, smbios_header::len, smbios_structure::offset, and UNULL.

Referenced by smbios_fetch().

                                                     {

        assert ( smbios.address != UNULL );

        if ( len > structure->header.len )
                len = structure->header.len;
        copy_from_user ( data, smbios.address, structure->offset, len );
        return 0;
}

int read_smbios_string	(	struct smbios_structure *	structure,
		unsigned int	index,
		void *	data,
		size_t	len
	)

Find indexed string within SMBIOS structure.

Parameters:

	structure	SMBIOS structure descriptor
	index	String index
	data	Buffer for string
	len	Length of string buffer

Return values:

rc

Length of string, or negative error

Definition at line 149 of file smbios.c.

References smbios::address, assert, copy_from_user(), DBG, ENOENT, smbios_structure::header, smbios_header::len, offset, smbios_structure::offset, smbios_structure::strings_len, strlen_user(), and UNULL.

Referenced by smbios_fetch().

                                                                      {
        size_t strings_start = ( structure->offset + structure->header.len );
        size_t strings_end = ( strings_start + structure->strings_len );
        size_t offset;
        size_t string_len;

        assert ( smbios.address != UNULL );

        /* String numbers start at 1 (0 is used to indicate "no string") */
        if ( ! index )
                return -ENOENT;

        for ( offset = strings_start ; offset < strings_end ;
              offset += ( string_len + 1 ) ) {
                /* Get string length.  This is known safe, since the
                 * smbios_strings struct is constructed so as to
                 * always end on a string boundary.
                 */
                string_len = strlen_user ( smbios.address, offset );
                if ( --index == 0 ) {
                        /* Copy string, truncating as necessary. */
                        if ( len > string_len )
                                len = string_len;
                        copy_from_user ( data, smbios.address, offset, len );
                        return string_len;
                }
        }

        DBG ( "SMBIOS string index %d not found\n", index );
        return -ENOENT;
}

---

Variable Documentation

struct smbios smbios [static]

Initial value:

 {
        .address = UNULL,
}

SMBIOS entry point descriptor.

Definition at line 35 of file smbios.c.