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.\"
.\" Copyright 2016 Netflix, Inc.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd October 25, 2018
.Dt LIBEFIVAR 3
.Os
.Sh NAME
.Nm libefivar
.Nd EFI Non Volatile Variable Support
.Sh SYNOPSIS
.In efivar.h
.Ft int
.Fn efi_append_variable "efi_guid_t guid" "const char *name" "void *data" "size_t data_size" "uint32_t attributes"
.Ft int
.Fn efi_del_variable "efi_guid_t guid" "const char *name"
.Ft int
.Fn efi_get_variable "efi_guid_t guid" "const char *name" "void **data" "ssize_t *data_size" "uint32_t *attributes"
.Ft int
.Fn efi_get_variable_attributes "efi_guid_t guid" "const char *name" "uint32_t *attributes"
.Ft int
.Fn efi_get_variable_size "efi_guid_t guid" "const char *name" "size_t *size"
.Ft int
.Fn efi_get_next_variable_name "efi_guid_t **guid" "char **name"
.Ft int
.Fn efi_guid_to_name "efi_guid_t *guid" "char **name"
.Ft int
.Fn efi_guid_to_symbol "efi_guid_t *guid" "char **symbol"
.Ft int
.Fn efi_guid_to_str "const efi_guid_t *guid" "char **sp"
.Ft int
.Fn efi_name_to_guid "const char *name" "efi_guid_t *guid"
.Ft int
.Fn efi_set_variable "efi_guid_t guid" "const char *name" "void *data" "size_t data_size" "uint32_t attributes"
.Ft int
.Fn efi_str_to_guid "const char *s" "efi_guid_t *guid"
.Ft int
.Fn efi_variables_supported "void"
.Sh DESCRIPTION
The
.Nm
library implements access to EFI Variables via the EFI Runtime
Services.
All
.Vt "char *"
strings are converted to 16-bit UTF strings before passing
them to EFI.
.Pp
.Fn efi_variables_supported
returns non-zero if the current machine supports setting of EFI firmware
variables and the kernel support for doing so is present.
Otherwise zero is returned.
.Pp
.Fn efi_del_variable
deletes the EFI variable selected by
.Va guid
and
.Va name .
.Pp
The following functions have not been implemented yet:
.Bl -dash -offset indent -compact
.It
.Fn efi_append_variable
.It
.Fn efi_get_next_variable_name
.It
.Fn efi_get_variable
.It
.Fn efi_get_variable_attributes
.It
.Fn efi_get_variable_size
.It
.Fn efi_guid_to_name
.It
.Fn efi_guid_to_str
.It
.Fn efi_guid_to_symbol
.It
.Fn efi_name_to_guid
.It
.Fn efi_set_variable
.It
.Fn efi_str_to_guid
.El
.Sh SEE ALSO
.Xr efidev 4
.Sh HISTORY
The
.Nm
library first appeared in
.Fx 12.0 .
.Sh AUTHORS
.An -nosplit
This software was originally written by
.An Warner Losh .
.Sh BUGS
No facilities exist to process the strings as native UTF.
This is a limitation in the Linux
.Nm
library interface.
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