bluez/peripheral/efivars.c
2015-04-28 09:19:12 -07:00

133 lines
3.0 KiB
C

/*
*
* BlueZ - Bluetooth protocol stack for Linux
*
* Copyright (C) 2015 Intel Corporation. All rights reserved.
*
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/uio.h>
#include "peripheral/efivars.h"
#define SYSFS_EFIVARS "/sys/firmware/efi/efivars"
typedef struct {
uint32_t data1;
uint16_t data2;
uint16_t data3;
uint8_t data4[8];
} efi_guid_t;
#define VENDOR_GUID \
(efi_guid_t) { 0xd5f9d775, 0x1a09, 0x4e89, \
{ 0x96, 0xcf, 0x1d, 0x19, 0x55, 0x4d, 0xa6, 0x67 } }
static void efivars_pathname(const char *name, char *pathname, size_t size)
{
static efi_guid_t guid = VENDOR_GUID;
snprintf(pathname, size - 1,
"%s/%s-%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
SYSFS_EFIVARS, name, guid.data1, guid.data2, guid.data3,
guid.data4[0], guid.data4[1], guid.data4[2], guid.data4[3],
guid.data4[4], guid.data4[5], guid.data4[6], guid.data4[7]);
}
int efivars_read(const char *name, uint32_t *attributes,
void *data, size_t size)
{
char pathname[PATH_MAX];
struct iovec iov[2];
uint32_t attr;
ssize_t len;
int fd;
efivars_pathname(name, pathname, PATH_MAX);
fd = open(pathname, O_RDONLY | O_CLOEXEC);
if (fd < 0)
return -EIO;
iov[0].iov_base = &attr;
iov[0].iov_len = sizeof(attr);
iov[1].iov_base = data;
iov[1].iov_len = size;
len = readv(fd, iov, 2);
close(fd);
if (len < 0)
return -EIO;
if (attributes)
*attributes = attr;
return 0;
}
int efivars_write(const char *name, uint32_t attributes,
const void *data, size_t size)
{
char pathname[PATH_MAX];
void *buf;
ssize_t written;
int fd;
efivars_pathname(name, pathname, PATH_MAX);
buf = malloc(size + sizeof(attributes));
if (!buf)
return -ENOMEM;
fd = open(pathname, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC,
S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (fd < 0) {
free(buf);
return -EIO;
}
memcpy(buf, &attributes, sizeof(attributes));
memcpy(buf + sizeof(attributes), data, size);
written = write(fd, buf, size + sizeof(attributes));
close(fd);
free(buf);
if (written < 0)
return -EIO;
return 0;
}