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/*
* Copyright (C) 2023 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 );
/**
* @file
*
* EFI variable settings
*
*/
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ipxe/settings.h>
#include <ipxe/init.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/Guid/GlobalVariable.h>
/** An EFI variable settings block */
struct efivar_settings {
/** Settings block */
struct settings settings;
/** Vendor GUID */
EFI_GUID guid;
};
/** EFI settings scope */
static const struct settings_scope efivar_scope;
/**
* Check applicability of EFI variable setting
*
* @v settings Settings block
* @v setting Setting
* @ret applies Setting applies within this settings block
*/
static int efivar_applies ( struct settings *settings __unused,
const struct setting *setting ) {
return ( setting->scope == &efivar_scope );
}
/**
* Fetch value of EFI variable setting
*
* @v settings Settings block
* @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 efivar_fetch ( struct settings *settings, struct setting *setting,
void *data, size_t len ) {
EFI_RUNTIME_SERVICES *rs = efi_systab->RuntimeServices;
struct efivar_settings *efivars =
container_of ( settings, struct efivar_settings, settings );
size_t name_len = strlen ( setting->name );
CHAR16 wname[ name_len + 1 /* wNUL */ ];
UINT32 attrs;
UINTN size;
void *buf;
unsigned int i;
EFI_STATUS efirc;
int rc;
/* Convert name to UCS-2 */
for ( i = 0 ; i <= name_len ; i++ )
wname[i] = setting->name[i];
/* Get variable length */
size = 0;
efirc = rs->GetVariable ( wname, &efivars->guid, &attrs, &size, NULL );
if ( ( efirc != 0 ) && ( efirc != EFI_BUFFER_TOO_SMALL ) ) {
rc = -EEFI ( efirc );
DBGC ( efivars, "EFIVAR %s:%s not present: %s\n",
efi_guid_ntoa ( &efivars->guid ), setting->name,
strerror ( rc ) );
goto err_len;
}
/* Allocate temporary buffer, since GetVariable() is not
* guaranteed to return partial data for an underlength
* buffer.
*/
buf = malloc ( size );
if ( ! buf ) {
rc = -ENOMEM;
goto err_alloc;
}
/* Get variable value */
if ( ( efirc = rs->GetVariable ( wname, &efivars->guid, &attrs, &size,
buf ) ) != 0 ) {
rc = -EEFI ( efirc );
DBGC ( efivars, "EFIVAR %s:%s could not get %zd bytes: %s\n",
efi_guid_ntoa ( &efivars->guid ), setting->name,
( ( size_t ) size ), strerror ( rc ) );
goto err_get;
}
DBGC ( efivars, "EFIVAR %s:%s:\n", efi_guid_ntoa ( &efivars->guid ),
setting->name );
DBGC_HDA ( efivars, 0, buf, size );
/* Return setting value */
if ( len > size )
len = size;
memcpy ( data, buf, len );
if ( ! setting->type )
setting->type = &setting_type_hex;
/* Free temporary buffer */
free ( buf );
return size;
err_get:
free ( buf );
err_alloc:
err_len:
return rc;
}
/** EFI variable settings operations */
static struct settings_operations efivar_operations = {
.applies = efivar_applies,
.fetch = efivar_fetch,
};
/** Well-known EFI variable settings blocks */
static struct efivar_settings efivar_settings[] = {
{ .settings = { .name = "efi" }, .guid = EFI_GLOBAL_VARIABLE },
};
/**
* Initialise EFI variable settings
*
*/
static void efivar_init ( void ) {
struct efivar_settings *efivars;
const char *name;
unsigned int i;
int rc;
/* Register all settings blocks */
for ( i = 0 ; i < ( sizeof ( efivar_settings ) /
sizeof ( efivar_settings[0] ) ) ; i++ ) {
/* Initialise settings block */
efivars = &efivar_settings[i];
settings_init ( &efivars->settings, &efivar_operations, NULL,
&efivar_scope );
/* Register settings block */
name = efivars->settings.name;
if ( ( rc = register_settings ( &efivars->settings, NULL,
name ) ) != 0 ) {
DBGC ( &efivar_settings, "EFIVAR could not register "
"%s: %s\n", name, strerror ( rc ) );
/* Continue trying to register remaining blocks */
}
}
}
/** EFI variable settings initialiser */
struct init_fn efivar_init_fn __init_fn ( INIT_NORMAL ) = {
.initialise = efivar_init,
};
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