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.\" $FreeBSD$ 27.\" 28.Dd October 25, 2018 29.Dt LIBEFIVAR 3 30.Os 31.Sh NAME 32.Nm libefivar 33.Nd EFI Non Volatile Variable Support 34.Sh SYNOPSIS 35.In efivar.h 36.Ft int 37.Fn efi_append_variable "efi_guid_t guid" "const char *name" "void *data" "size_t data_size" "uint32_t attributes" 38.Ft int 39.Fn efi_del_variable "efi_guid_t guid" "const char *name" 40.Ft int 41.Fn efi_get_variable "efi_guid_t guid" "const char *name" "void **data" "ssize_t *data_size" "uint32_t *attributes" 42.Ft int 43.Fn efi_get_variable_attributes "efi_guid_t guid" "const char *name" "uint32_t *attributes" 44.Ft int 45.Fn efi_get_variable_size "efi_guid_t guid" "const char *name" "size_t *size" 46.Ft int 47.Fn efi_get_next_variable_name "efi_guid_t **guid" "char **name" 48.Ft int 49.Fn efi_guid_to_name "efi_guid_t *guid" "char **name" 50.Ft int 51.Fn efi_guid_to_symbol "efi_guid_t *guid" "char **symbol" 52.Ft int 53.Fn efi_guid_to_str "const efi_guid_t *guid" "char **sp" 54.Ft int 55.Fn efi_name_to_guid "const char *name" "efi_guid_t *guid" 56.Ft int 57.Fn efi_set_variable "efi_guid_t guid" "const char *name" "void *data" "size_t data_size" "uint32_t attributes" 58.Ft int 59.Fn efi_str_to_guid "const char *s" "efi_guid_t *guid" 60.Ft int 61.Fn efi_variables_supported "void" 62.Sh DESCRIPTION 63The 64.Nm 65library implements access to EFI Variables via the EFI Runtime 66Services. 67All 68.Vt "char *" 69strings are converted to 16-bit UTF strings before passing 70them to EFI. 71.Pp 72.Fn efi_variables_supported 73returns non-zero if the current machine supports setting of EFI firmware 74variables and the kernel support for doing so is present. 75Otherwise zero is returned. 76.Pp 77.Fn efi_del_variable 78deletes the EFI variable selected by 79.Va guid 80and 81.Va name . 82.Pp 83The following functions have not been implemented yet: 84.Bl -dash -offset indent -compact 85.It 86.Fn efi_append_variable 87.It 88.Fn efi_get_next_variable_name 89.It 90.Fn efi_get_variable 91.It 92.Fn efi_get_variable_attributes 93.It 94.Fn efi_get_variable_size 95.It 96.Fn efi_guid_to_name 97.It 98.Fn efi_guid_to_str 99.It 100.Fn efi_guid_to_symbol 101.It 102.Fn efi_name_to_guid 103.It 104.Fn efi_set_variable 105.It 106.Fn efi_str_to_guid 107.El 108.Sh SEE ALSO 109.Xr efidev 4 110.Sh HISTORY 111The 112.Nm 113library first appeared in 114.Fx 12.0 . 115.Sh AUTHORS 116.An -nosplit 117This software was originally written by 118.An Warner Losh . 119.Sh BUGS 120No facilities exist to process the strings as native UTF. 121This is a limitation in the Linux 122.Nm 123library interface. 124