smbios.c File Reference

System Management BIOS. More...

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

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
static uint8_t	smbios_checksum (const void *start, size_t len)
	Calculate SMBIOS entry point structure checksum.
const struct smbios_entry *	find_smbios_entry (const void *start, size_t len)
	Scan for SMBIOS 32-bit entry point structure.
const struct smbios3_entry *	find_smbios3_entry (const void *start, size_t len)
	Scan for SMBIOS 64-bit entry point structure.
static size_t	find_strings_terminator (size_t offset)
	Find SMBIOS strings terminator.
const struct smbios_header *	smbios_structure (unsigned int type, unsigned int instance)
	Find specific structure type within SMBIOS.
const char *	smbios_string (const struct smbios_header *structure, unsigned int index)
	Get indexed string within SMBIOS structure.
int	smbios_version (void)
	Get SMBIOS version.
void	smbios_clear (void)
	Clear SMBIOS entry point descriptor.

Variables
static struct smbios	smbios
	SMBIOS entry point descriptor.

Detailed Description

System Management BIOS.

Definition in file smbios.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

smbios_checksum()

uint8_t smbios_checksum ( const void * start, size_t len )

static

Calculate SMBIOS entry point structure checksum.

Parameters

start	Start address of region
len	Length of entry point structure

Return values

sum	Byte checksum

Definition at line 52 of file smbios.c.

                                                                 {
        const uint8_t *byte = start;
        uint8_t sum = 0;
 
        /* Compute checksum */
        while ( len-- )
                sum += *(byte++);
 
        return sum;
}

References len, and start.

Referenced by find_smbios3_entry(), and find_smbios_entry().

find_smbios_entry()

const struct smbios_entry * find_smbios_entry	(	const void *	start,
		size_t	len )

Scan for SMBIOS 32-bit entry point structure.

Parameters

start	Start address of region to scan
len	Length of region to scan

Return values

entry

SMBIOS entry point structure, or NULL if not found

Definition at line 70 of file smbios.c.

                                                             {
        static size_t offset = 0; /* Avoid repeated attempts to locate SMBIOS */
        const struct smbios_entry *entry;
        uint8_t sum;
 
        /* Try to find SMBIOS */
        for ( ; ( offset + sizeof ( *entry ) ) <= len ; offset += 0x10 ) {
 
                /* Verify signature */
                entry = ( start + offset );
                if ( entry->signature != SMBIOS_SIGNATURE )
                        continue;
 
                /* Verify length */
                if ( ( entry->len < sizeof ( *entry ) ) ||
                     ( ( offset + entry->len ) > len ) ) {
                        DBGC ( &smbios, "SMBIOS at %#08lx has bad length "
                               "%#02x\n", virt_to_phys ( entry ), entry->len );
                        continue;
                }
 
                /* Verify checksum */
                if ( ( sum = smbios_checksum ( entry, entry->len ) ) != 0 ) {
                        DBGC ( &smbios, "SMBIOS at %#08lx has bad checksum "
                               "%#02x\n", virt_to_phys ( entry ), sum );
                        continue;
                }
 
                /* Fill result structure */
                DBGC ( &smbios, "Found SMBIOS v%d.%d entry point at %#08lx\n",
                       entry->major, entry->minor, virt_to_phys ( entry ) );
                return entry;
        }
 
        DBGC ( &smbios, "No SMBIOS found\n" );
        return NULL;
}

References DBGC, len, smbios_entry::len, smbios_entry::major, smbios_entry::minor, NULL, offset, smbios_entry::signature, smbios_checksum(), SMBIOS_SIGNATURE, and start.

Referenced by bios_find_smbios2().

find_smbios3_entry()

const struct smbios3_entry * find_smbios3_entry	(	const void *	start,
		size_t	len )

Scan for SMBIOS 64-bit entry point structure.

Parameters

start	Start address of region to scan
len	Length of region to scan

Return values

entry

SMBIOS entry point structure, or NULL if not found

Definition at line 116 of file smbios.c.

                                                               {
        static size_t offset = 0; /* Avoid repeated attempts to locate SMBIOS */
        const struct smbios3_entry *entry;
        uint8_t sum;
 
        /* Try to find SMBIOS */
        for ( ; ( offset + sizeof ( *entry ) ) <= len ; offset += 0x10 ) {
 
                /* Verify signature */
                entry = ( start + offset );
                if ( entry->signature != SMBIOS3_SIGNATURE )
                        continue;
 
                /* Verify length */
                if ( ( entry->len < sizeof ( *entry ) ) ||
                     ( ( offset + entry->len ) > len ) ) {
                        DBGC ( &smbios, "SMBIOS at %#08lx has bad length "
                               "%#02x\n", virt_to_phys ( entry ), entry->len );
                        continue;
                }
 
                /* Verify checksum */
                if ( ( sum = smbios_checksum ( entry, entry->len ) ) != 0 ) {
                        DBGC ( &smbios, "SMBIOS3 at %#08lx has bad checksum "
                               "%#02x\n", virt_to_phys ( entry ), sum );
                        continue;
                }
 
                /* Fill result structure */
                DBGC ( &smbios, "Found SMBIOS3 v%d.%d entry point at %#08lx\n",
                       entry->major, entry->minor, virt_to_phys ( entry ) );
                return entry;
        }
 
        DBGC ( &smbios, "No SMBIOS3 found\n" );
        return NULL;
}

References DBGC, len, smbios3_entry::len, smbios3_entry::major, smbios3_entry::minor, NULL, offset, smbios3_entry::signature, SMBIOS3_SIGNATURE, smbios_checksum(), and start.

Referenced by bios_find_smbios3().

find_strings_terminator()

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 161 of file smbios.c.

                                                        {
        const uint16_t *nulnul __attribute__ (( aligned ( 1 ) ));
 
        /* Sanity checks */
        assert ( smbios.address != NULL );
 
        /* Check for presence of terminating empty string */
        for ( ; ( offset + sizeof ( *nulnul ) ) <= smbios.len ; offset++ ) {
                nulnul = ( smbios.address + offset );
                if ( *nulnul == 0 )
                        return ( offset + 1 );
        }
        return 0;
}

References __attribute__, smbios::address, assert, smbios::len, NULL, and offset.

Referenced by smbios_structure().

smbios_structure()

const struct smbios_header * smbios_structure	(	unsigned int	type,
		unsigned int	instance )

Find specific structure type within SMBIOS.

Parameters

type	Structure type to search for
instance	Instance of this type of structure

Return values

structure

SMBIOS structure header, or NULL if not found

Definition at line 183 of file smbios.c.

                                                                        {
        const struct smbios_header *structure;
        unsigned int count = 0;
        size_t offset = 0;
        size_t strings_offset;
        size_t terminator_offset;
        size_t strings_len;
        int rc;
 
        /* Find SMBIOS */
        if ( ( smbios.address == NULL ) &&
             ( ( rc = find_smbios ( &smbios ) ) != 0 ) )
                return NULL;
        assert ( smbios.address != NULL );
 
        /* Scan through list of structures */
        while ( ( ( offset + sizeof ( *structure ) ) < smbios.len ) &&
                ( ( smbios.count == 0 ) || ( count < smbios.count ) ) ) {
 
                /* Access next SMBIOS structure header */
                structure = ( smbios.address + offset );
 
                /* Determine start and extent of strings block */
                strings_offset = ( offset + structure->len );
                if ( strings_offset > smbios.len ) {
                        DBGC ( &smbios, "SMBIOS structure at offset %#zx "
                               "with length %#x extends beyond SMBIOS\n",
                               offset, structure->len );
                        return NULL;
                }
                terminator_offset = find_strings_terminator ( strings_offset );
                if ( ! terminator_offset ) {
                        DBGC ( &smbios, "SMBIOS structure at offset %#zx has "
                               "unterminated strings section\n", offset );
                        return NULL;
                }
                strings_len = ( terminator_offset - strings_offset);
                DBGC ( &smbios, "SMBIOS structure at offset %#zx has type %d, "
                       "length %#x, strings length %#zx\n", offset,
                       structure->type, structure->len, strings_len );
 
                /* Stop if we have reached an end-of-table marker */
                if ( ( smbios.count == 0 ) &&
                     ( structure->type == SMBIOS_TYPE_END ) )
                        break;
 
                /* If this is the structure we want, return */
                if ( ( structure->type == type ) &&
                     ( instance-- == 0 ) ) {
                        return structure;
                }
 
                /* Move to next SMBIOS structure */
                offset = ( terminator_offset + 1 );
                count++;
        }
 
        DBGC ( &smbios, "SMBIOS structure type %d not found\n", type );
        return NULL;
}

References smbios::address, assert, count, smbios::count, DBGC, find_smbios(), find_strings_terminator(), smbios::len, smbios_header::len, NULL, offset, rc, SMBIOS_TYPE_END, smbios_header::type, and type.

Referenced by smbios_fetch(), and smsc95xx_vm3_fetch_mac().

smbios_string()

const char * smbios_string	(	const struct smbios_header *	structure,
		unsigned int	index )

Get indexed string within SMBIOS structure.

Parameters

structure	SMBIOS structure header
index	String index

Return values

string

SMBIOS string, or NULL if not fond

Definition at line 252 of file smbios.c.

                                                  {
        const char *string;
        unsigned int i;
        size_t len;
 
        /* Sanity check */
        assert ( smbios.address != NULL );
 
        /* Step through strings */
        string = ( ( ( const void * ) structure ) + structure->len );
        for ( i = index ; i-- ; ) {
                /* Get string length.  This is known safe, since we
                 * check for the empty-string terminator in
                 * smbios_structure().
                 */
                len = strlen ( string );
                if ( ! len )
                        break;
                if ( i == 0 )
                        return string;
                string += ( len + 1 /* NUL */ );
        }
 
        DBGC ( &smbios, "SMBIOS string index %d not found\n", index );
        return NULL;
}

References smbios::address, assert, DBGC, index, len, smbios_header::len, NULL, string, and strlen().

Referenced by smbios_fetch(), and smsc95xx_vm3_fetch_mac().

smbios_version()

int smbios_version

(

void

)

Get SMBIOS version.

Return values

version

Version, or negative error

Definition at line 285 of file smbios.c.

                            {
        int rc;
 
        /* Find SMBIOS */
        if ( ( smbios.address == NULL ) &&
             ( ( rc = find_smbios ( &smbios ) ) != 0 ) )
                return rc;
        assert ( smbios.address != NULL );
 
        return smbios.version;
}

References smbios::address, assert, find_smbios(), NULL, rc, and smbios::version.

Referenced by smbios_fetch().

smbios_clear()

void smbios_clear

(

void

)

Clear SMBIOS entry point descriptor.

Definition at line 301 of file smbios.c.

                           {
 
        /* Clear address */
        smbios.address = NULL;
}

References smbios::address, and NULL.

Variable Documentation

smbios

struct smbios smbios

static

Initial value:

= {
        .address = NULL,
}

SMBIOS entry point descriptor.

Definition at line 41 of file smbios.c.

                              {
        .address = NULL,
};