efi_settings.c File Reference

EFI variable settings. More...

#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/efi_strings.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
static int	efivars_applies (struct settings *settings __unused, const struct setting *setting)
	Check applicability of EFI variable setting. More...
static int	efivars_find (const CHAR16 *wname, EFI_GUID *guid)
	Find first matching EFI variable name. More...
static int	efivars_fetch (struct settings *settings __unused, struct setting *setting, void *data, size_t len)
	Fetch value of EFI variable setting. More...
static void	efivars_init (void)
	Initialise EFI variable settings. More...
struct init_fn efivars_init_fn	__init_fn (INIT_NORMAL)
	EFI variable settings initialiser. More...

Variables
static const struct settings_scope	efivars_scope
	EFI variable settings scope. More...
static struct settings	efivars
	EFI variable settings. More...
static struct settings_operations	efivars_operations
	EFI variable settings operations. More...

Detailed Description

EFI variable settings.

Definition in file efi_settings.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

efivars_applies()

static int efivars_applies ( struct settings *settings  __unused, const struct setting *  setting  )

static

Check applicability of EFI variable setting.

Parameters

settings	Settings block
setting	Setting

Return values

applies

Setting applies within this settings block

Definition at line 55 of file efi_settings.c.

                                                             {

        return ( setting->scope == &efivars_scope );
}

References efivars_scope, and setting::scope.

efivars_find()

static int efivars_find ( const CHAR16 *  wname, EFI_GUID *  guid  )

static

Find first matching EFI variable name.

Parameters

wname	Name
guid	GUID to fill in

Return values

rc	Return status code

Definition at line 68 of file efi_settings.c.

                                                                {
        EFI_RUNTIME_SERVICES *rs = efi_systab->RuntimeServices;
        size_t wname_len = ( ( wcslen ( wname ) + 1 ) * sizeof ( wname[0] ) );
        CHAR16 *buf;
        CHAR16 *tmp;
        UINTN size;
        EFI_STATUS efirc;
        int rc;

        /* Allocate single wNUL for first call to GetNextVariableName() */
        size = sizeof ( buf[0] );
        buf = zalloc ( size );
        if ( ! buf )
                return -ENOMEM;

        /* Iterate over all veriables */
        while ( 1 ) {

                /* Get next variable name */
                efirc = rs->GetNextVariableName ( &size, buf, guid );
                if ( efirc == EFI_BUFFER_TOO_SMALL ) {
                        tmp = realloc ( buf, size );
                        if ( ! tmp ) {
                                rc = -ENOMEM;
                                break;
                        }
                        buf = tmp;
                        efirc = rs->GetNextVariableName ( &size, buf, guid );
                }
                if ( efirc == EFI_NOT_FOUND ) {
                        rc = -ENOENT;
                        break;
                }
                if ( efirc != 0 ) {
                        rc = -EEFI ( efirc );
                        DBGC ( &efivars, "EFIVARS %s:%ls could not fetch next "
                               "variable name: %s\n",
                               efi_guid_ntoa ( guid ), buf, strerror ( rc ) );
                        break;
                }
                DBGC2 ( &efivars, "EFIVARS %s:%ls exists\n",
                        efi_guid_ntoa ( guid ), buf );

                /* Check for matching variable name */
                if ( memcmp ( wname, buf, wname_len ) == 0 ) {
                        rc = 0;
                        break;
                }
        }

        /* Free temporary buffer */
        free ( buf );

        return rc;
}

References DBGC, DBGC2, EEFI, EFI_BUFFER_TOO_SMALL, efi_guid_ntoa(), EFI_NOT_FOUND, efi_systab, efivars, ENOENT, ENOMEM, free, EFI_RUNTIME_SERVICES::GetNextVariableName, guid, memcmp(), rc, realloc(), EFI_SYSTEM_TABLE::RuntimeServices, size, strerror(), tmp, wcslen(), and zalloc().

Referenced by efivars_fetch().

efivars_fetch()

static int efivars_fetch ( struct settings *settings  __unused, struct setting *  setting, void *  data, size_t  len  )

static

Fetch value of EFI variable setting.

Parameters

settings	Settings block
setting	Setting to fetch
data	Buffer to fill with setting data
len	Length of buffer

Return values

len	Length of setting data, or negative error

Definition at line 133 of file efi_settings.c.

                                                                             {
        EFI_RUNTIME_SERVICES *rs = efi_systab->RuntimeServices;
        size_t name_len = strlen ( setting->name );
        CHAR16 wname[ name_len + 1 /* wNUL */ ];
        EFI_GUID guid;
        UINT32 attrs;
        UINTN size;
        void *buf;
        EFI_STATUS efirc;
        int rc;

        /* Convert name to UCS-2 */
        efi_snprintf ( wname, sizeof ( wname ), "%s", setting->name );

        /* Find variable GUID */
        if ( ( rc = efivars_find ( wname, &guid ) ) != 0 )
                goto err_find;

        /* Get variable length */
        size = 0;
        if ( ( efirc = rs->GetVariable ( wname, &guid, &attrs, &size,
                                         NULL ) != EFI_BUFFER_TOO_SMALL ) ) {
                rc = -EEFI ( efirc );
                DBGC ( &efivars, "EFIVARS %s:%ls could not get size: %s\n",
                       efi_guid_ntoa ( &guid ), wname, 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, &guid, &attrs, &size,
                                         buf ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( &efivars, "EFIVARS %s:%ls could not get %zd bytes: "
                       "%s\n", efi_guid_ntoa ( &guid ), wname,
                       ( ( size_t ) size ), strerror ( rc ) );
                goto err_get;
        }
        DBGC ( &efivars, "EFIVARS %s:%ls:\n", efi_guid_ntoa ( &guid ), wname );
        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:
 err_find:
        return rc;
}

References data, DBGC, DBGC_HDA, EEFI, EFI_BUFFER_TOO_SMALL, efi_guid_ntoa(), efi_snprintf(), efi_systab, efivars, efivars_find(), ENOMEM, free, EFI_RUNTIME_SERVICES::GetVariable, guid, len, malloc(), memcpy(), setting::name, NULL, rc, EFI_SYSTEM_TABLE::RuntimeServices, size, strerror(), strlen(), and setting::type.

efivars_init()

static void efivars_init ( void  )

static

Initialise EFI variable settings.

Definition at line 223 of file efi_settings.c.

                                  {
        int rc;

        /* Register settings block */
        if ( ( rc = register_settings ( &efivars, NULL, "efi" ) ) != 0 ) {
                DBGC ( &efivars, "EFIVARS could not register: %s\n",
                       strerror ( rc ) );
                return;
        }
}

References DBGC, efivars, NULL, rc, register_settings(), and strerror().

__init_fn()

struct init_fn efivars_init_fn __init_fn

(

INIT_NORMAL

)

EFI variable settings initialiser.

Variable Documentation

efivars_scope

const struct settings_scope efivars_scope

static

EFI variable settings scope.

Definition at line 43 of file efi_settings.c.

Referenced by efivars_applies().

efivars

static struct settings efivars

static

Initial value:

= {
        .refcnt = NULL,
        .siblings = LIST_HEAD_INIT ( efivars.siblings ),
        .children = LIST_HEAD_INIT ( efivars.children ),
        .op = &efivars_operations,
        .default_scope = &efivars_scope,
}

EFI variable settings.

Definition at line 46 of file efi_settings.c.

Referenced by efivars_fetch(), efivars_find(), and efivars_init().

efivars_operations

struct settings_operations efivars_operations

static

Initial value:

= {
        .applies = efivars_applies,
        .fetch = efivars_fetch,
}

EFI variable settings operations.

Definition at line 205 of file efi_settings.c.