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Manual Pages  — LIBEFIVAR

NAME

libefivar – EFI Non Volatile Variable Support

CONTENTS

SYNOPSIS

#include <efivar.h>

int
efi_append_variable(efi_guid_t guid, const char *name, void *data, size_t data_size, uint32_t attributes);

int
efi_del_variable(efi_guid_t guid, const char *name);

int
efi_get_variable(efi_guid_t guid, const char *name, void **data, ssize_t *data_size, uint32_t *attributes);

int
efi_get_variable_attributes(efi_guid_t guid, const char *name, uint32_t *attributes);

int
efi_get_variable_size(efi_guid_t guid, const char *name, size_t *size);

int
efi_get_next_variable_name(efi_guid_t **guid, char **name);

int
efi_guid_to_name(efi_guid_t *guid, char **name);

int
efi_guid_to_symbol(efi_guid_t *guid, char **symbol);

int
efi_guid_to_str(const efi_guid_t *guid, char **sp);

int
efi_name_to_guid(const char *name, efi_guid_t *guid);

int
efi_set_variable(efi_guid_t guid, const char *name, void *data, size_t data_size, uint32_t attributes);

int
efi_str_to_guid(const char *s, efi_guid_t *guid);

int
efi_variables_supported(void);

DESCRIPTION

The libefivar library implements access to EFI Variables via the EFI Runtime Services. All char * strings are converted to 16-bit UTF strings before passing them to EFI.

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.

efi_del_variable() deletes the EFI variable selected by guid and name.

The following functions have not been implemented yet:
efi_append_variable()
efi_get_next_variable_name()
efi_get_variable()
efi_get_variable_attributes()
efi_get_variable_size()
efi_guid_to_name()
efi_guid_to_str()
efi_guid_to_symbol()
efi_name_to_guid()
efi_set_variable()
efi_str_to_guid()

SEE ALSO

efidev(4)

HISTORY

The libefivar library first appeared in FreeBSD 12.0 .

AUTHORS

This software was originally written by Warner Losh.

BUGS

No facilities exist to process the strings as native UTF. This is a limitation in the Linux libefivar library interface.

LIBEFIVAR (3) October 25, 2018

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