1.\" 2.\" Copyright 2016 Netflix, Inc. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.Dd October 25, 2018 27.Dt LIBEFIVAR 3 28.Os 29.Sh NAME 30.Nm libefivar 31.Nd EFI Non Volatile Variable Support 32.Sh SYNOPSIS 33.In efivar.h 34.Ft int 35.Fn efi_append_variable "efi_guid_t guid" "const char *name" "void *data" "size_t data_size" "uint32_t attributes" 36.Ft int 37.Fn efi_del_variable "efi_guid_t guid" "const char *name" 38.Ft int 39.Fn efi_get_variable "efi_guid_t guid" "const char *name" "void **data" "ssize_t *data_size" "uint32_t *attributes" 40.Ft int 41.Fn efi_get_variable_attributes "efi_guid_t guid" "const char *name" "uint32_t *attributes" 42.Ft int 43.Fn efi_get_variable_size "efi_guid_t guid" "const char *name" "size_t *size" 44.Ft int 45.Fn efi_get_next_variable_name "efi_guid_t **guid" "char **name" 46.Ft int 47.Fn efi_guid_to_name "efi_guid_t *guid" "char **name" 48.Ft int 49.Fn efi_guid_to_symbol "efi_guid_t *guid" "char **symbol" 50.Ft int 51.Fn efi_guid_to_str "const efi_guid_t *guid" "char **sp" 52.Ft int 53.Fn efi_name_to_guid "const char *name" "efi_guid_t *guid" 54.Ft int 55.Fn efi_set_variable "efi_guid_t guid" "const char *name" "void *data" "size_t data_size" "uint32_t attributes" 56.Ft int 57.Fn efi_str_to_guid "const char *s" "efi_guid_t *guid" 58.Ft int 59.Fn efi_variables_supported "void" 60.Sh DESCRIPTION 61The 62.Nm 63library implements access to EFI Variables via the EFI Runtime 64Services. 65All 66.Vt "char *" 67strings are converted to 16-bit UTF strings before passing 68them to EFI. 69.Pp 70.Fn efi_variables_supported 71returns non-zero if the current machine supports setting of EFI firmware 72variables and the kernel support for doing so is present. 73Otherwise zero is returned. 74.Pp 75.Fn efi_del_variable 76deletes the EFI variable selected by 77.Va guid 78and 79.Va name . 80.Pp 81The following functions have not been implemented yet: 82.Bl -dash -offset indent -compact 83.It 84.Fn efi_append_variable 85.It 86.Fn efi_get_next_variable_name 87.It 88.Fn efi_get_variable 89.It 90.Fn efi_get_variable_attributes 91.It 92.Fn efi_get_variable_size 93.It 94.Fn efi_guid_to_name 95.It 96.Fn efi_guid_to_str 97.It 98.Fn efi_guid_to_symbol 99.It 100.Fn efi_name_to_guid 101.It 102.Fn efi_set_variable 103.It 104.Fn efi_str_to_guid 105.El 106.Sh SEE ALSO 107.Xr efidev 4 108.Sh HISTORY 109The 110.Nm 111library first appeared in 112.Fx 12.0 . 113.Sh AUTHORS 114.An -nosplit 115This software was originally written by 116.An Warner Losh . 117.Sh BUGS 118No facilities exist to process the strings as native UTF. 119This is a limitation in the Linux 120.Nm 121library interface. 122