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[Settings] Expose SMBIOS via settings API
In particular, expose the system UUID as a setting ("smbios/uuid").
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Michael Brown committed Mar 28, 2008
1 parent aa74a7d commit feade5d
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Showing 9 changed files with 329 additions and 138 deletions.
193 changes: 81 additions & 112 deletions src/arch/i386/firmware/pcbios/smbios.c
Expand Up @@ -18,10 +18,9 @@

#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <assert.h>
#include <gpxe/uaccess.h>
#include <gpxe/uuid.h>
#include <realmode.h>
#include <pnpbios.h>
#include <smbios.h>
Expand Down Expand Up @@ -51,7 +50,7 @@ struct smbios_entry {
/** Checksum */
uint8_t checksum;
/** Length */
uint8_t length;
uint8_t len;
/** Major version */
uint8_t major;
/** Minor version */
Expand All @@ -67,7 +66,7 @@ struct smbios_entry {
/** DMI checksum */
uint8_t dmi_checksum;
/** Structure table length */
uint16_t smbios_length;
uint16_t smbios_len;
/** Structure table address */
physaddr_t smbios_address;
/** Number of SMBIOS structures */
Expand All @@ -86,49 +85,37 @@ struct smbios {
/** Start of SMBIOS structures */
userptr_t address;
/** Length of SMBIOS structures */
size_t length;
size_t len;
/** Number of SMBIOS structures */
unsigned int count;
};

/**
* SMBIOS strings descriptor
*
* This is returned as part of the search for an SMBIOS structure, and
* contains the information needed for extracting the strings within
* the "unformatted" portion of the structure.
*/
struct smbios_strings {
/** Start of strings data */
userptr_t data;
/** Length of strings data */
size_t length;
/** SMBIOS entry point descriptor */
static struct smbios smbios = {
.address = UNULL,
};

/**
* Find SMBIOS
*
* @ret smbios SMBIOS entry point descriptor, or NULL if not found
* @ret rc Return status code
*/
static struct smbios * find_smbios ( void ) {
static struct smbios smbios = {
.address = UNULL,
};
static int find_smbios ( void ) {
union {
struct smbios_entry entry;
uint8_t bytes[256]; /* 256 is maximum length possible */
} u;
unsigned int offset;
static unsigned int offset = 0;
size_t len;
unsigned int i;
uint8_t sum;

/* Return cached result if available */
/* Return cached result if avaiable */
if ( smbios.address != UNULL )
return &smbios;
return 0;

/* Try to find SMBIOS */
for ( offset = 0 ; offset < 0x10000 ; offset += 0x10 ) {
for ( ; offset < 0x10000 ; offset += 0x10 ) {

/* Read start of header and verify signature */
copy_from_real ( &u.entry, BIOS_SEG, offset,
Expand All @@ -137,7 +124,7 @@ static struct smbios * find_smbios ( void ) {
continue;

/* Read whole header and verify checksum */
len = u.entry.length;
len = u.entry.len;
copy_from_real ( &u.bytes, BIOS_SEG, offset, len );
for ( i = 0 , sum = 0 ; i < len ; i++ ) {
sum += u.bytes[i];
Expand All @@ -152,29 +139,27 @@ static struct smbios * find_smbios ( void ) {
DBG ( "Found SMBIOS entry point at %04x:%04x\n",
BIOS_SEG, offset );
smbios.address = phys_to_user ( u.entry.smbios_address );
smbios.length = u.entry.smbios_length;
smbios.len = u.entry.smbios_len;
smbios.count = u.entry.smbios_count;
return &smbios;
return 0;
}

DBG ( "No SMBIOS found\n" );
return NULL;
return -ENODEV;
}

/**
* Find SMBIOS strings terminator
*
* @v smbios SMBIOS entry point descriptor
* @v offset Offset to start of strings
* @ret offset Offset to strings terminator, or 0 if not found
*/
static size_t find_strings_terminator ( struct smbios *smbios,
size_t offset ) {
size_t max_offset = ( smbios->length - 2 );
static size_t find_strings_terminator ( size_t offset ) {
size_t max_offset = ( smbios.len - 2 );
uint16_t nulnul;

for ( ; offset <= max_offset ; offset++ ) {
copy_from_user ( &nulnul, smbios->address, offset, 2 );
copy_from_user ( &nulnul, smbios.address, offset, 2 );
if ( nulnul == 0 )
return ( offset + 1 );
}
Expand All @@ -185,66 +170,52 @@ static size_t find_strings_terminator ( struct smbios *smbios,
* Find specific structure type within SMBIOS
*
* @v type Structure type to search for
* @v structure Buffer to fill in with structure
* @v length Length of buffer
* @v strings Strings descriptor to fill in, or NULL
* @v structure SMBIOS structure descriptor to fill in
* @ret rc Return status code
*/
int find_smbios_structure ( unsigned int type, void *structure,
size_t length, struct smbios_strings *strings ) {
struct smbios *smbios;
struct smbios_header header;
struct smbios_strings temp_strings;
int find_smbios_structure ( unsigned int type,
struct smbios_structure *structure ) {
unsigned int count = 0;
size_t offset = 0;
size_t strings_offset;
size_t terminator_offset;
int rc;

/* Locate SMBIOS entry point */
if ( ! ( smbios = find_smbios() ) )
return -ENOENT;

/* Ensure that we have a usable strings descriptor buffer */
if ( ! strings )
strings = &temp_strings;
/* Find SMBIOS */
if ( ( rc = find_smbios() ) != 0 )
return rc;

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

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

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

DBG ( "SMBIOS structure at offset %zx has type %d, "
"length %x, strings length %zx\n",
offset, header.type, header.length, strings->length );
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 ( header.type == type ) {
if ( length > header.length )
length = header.length;
copy_from_user ( structure, smbios->address,
offset, length );
if ( structure->header.type == type ) {
structure->offset = offset;
return 0;
}

Expand All @@ -257,67 +228,65 @@ int find_smbios_structure ( unsigned int type, void *structure,
return -ENOENT;
}

/**
* Copy SMBIOS structure
*
* @v structure SMBIOS structure descriptor
* @v data Buffer to hold SMBIOS structure
* @v len Length of buffer
* @ret rc Return status code
*/
int read_smbios_structure ( struct smbios_structure *structure,
void *data, size_t len ) {

assert ( smbios.address != UNULL );

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

/**
* Find indexed string within SMBIOS structure
*
* @v strings SMBIOS strings descriptor
* @v structure SMBIOS structure descriptor
* @v index String index
* @v buffer Buffer for string
* @v length Length of string buffer
* @ret rc Return status code
* @v data Buffer for string
* @v len Length of string buffer
* @ret rc Length of string, or negative error
*/
int find_smbios_string ( struct smbios_strings *strings, unsigned int index,
char *buffer, size_t length ) {
size_t offset = 0;
int read_smbios_string ( struct smbios_structure *structure,
unsigned int index, void *data, size_t len ) {
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;

/* Zero buffer. This ensures that a valid NUL terminator is
* always present (unless length==0).
*/
memset ( buffer, 0, length );

assert ( smbios.address != UNULL );

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

while ( offset < strings->length ) {
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 ( strings->data, offset );
string_len = strlen_user ( smbios.address,
( structure->offset + offset ) );
if ( --index == 0 ) {
/* Copy string, truncating as necessary. */
if ( string_len >= length )
string_len = ( length - 1 );
copy_from_user ( buffer, strings->data,
offset, string_len );
return 0;
if ( len > string_len )
len = string_len;
copy_from_user ( data, smbios.address,
( structure->offset + offset ), len );
return string_len;
}
offset += ( string_len + 1 );
}

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

/**
* Get UUID from SMBIOS
*
* @v uuid UUID to fill in
* @ret rc Return status code
*/
int smbios_get_uuid ( union uuid *uuid ) {
struct smbios_system_information sysinfo;
int rc;

if ( ( rc = find_smbios_structure ( SMBIOS_TYPE_SYSTEM_INFORMATION,
&sysinfo, sizeof ( sysinfo ),
NULL ) ) != 0 )
return rc;

memcpy ( uuid, sysinfo.uuid, sizeof ( *uuid ) );
DBG ( "SMBIOS found UUID %s\n", uuid_ntoa ( uuid ) );

return 0;
}

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