aboutsummaryrefslogtreecommitdiff
path: root/tools/wmi/dell-smbios-example.c
blob: 9d3bde081249f461947531f649f240b00d5ef522 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
/*
 *  Sample application for SMBIOS communication over WMI interface
 *  Performs the following:
 *  - Simple cmd_class/cmd_select lookup for TPM information
 *  - Simple query of known tokens and their values
 *  - Simple activation of a token
 *
 *  Copyright (C) 2017 Dell, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <unistd.h>

/* if uapi header isn't installed, this might not yet exist */
#ifndef __packed
#define __packed __attribute__((packed))
#endif
#include <linux/wmi.h>

/* It would be better to discover these using udev, but for a simple
 * application they're hardcoded
 */
static const char *ioctl_devfs = "/dev/wmi/dell-smbios";
static const char *token_sysfs =
			"/sys/bus/platform/devices/dell-smbios.0/tokens";

static void show_buffer(struct dell_wmi_smbios_buffer *buffer)
{
	printf("Call: %x/%x [%x,%x,%x,%x]\nResults: [%8x,%8x,%8x,%8x]\n",
	buffer->std.cmd_class, buffer->std.cmd_select,
	buffer->std.input[0], buffer->std.input[1],
	buffer->std.input[2], buffer->std.input[3],
	buffer->std.output[0], buffer->std.output[1],
	buffer->std.output[2], buffer->std.output[3]);
}

static int run_wmi_smbios_cmd(struct dell_wmi_smbios_buffer *buffer)
{
	int fd;
	int ret;

	fd = open(ioctl_devfs, O_NONBLOCK);
	ret = ioctl(fd, DELL_WMI_SMBIOS_CMD, buffer);
	close(fd);
	return ret;
}

static int find_token(__u16 token, __u16 *location, __u16 *value)
{
	char location_sysfs[60];
	char value_sysfs[57];
	char buf[4096];
	FILE *f;
	int ret;

	ret = sprintf(value_sysfs, "%s/%04x_value", token_sysfs, token);
	if (ret < 0) {
		printf("sprintf value failed\n");
		return 2;
	}
	f = fopen(value_sysfs, "rb");
	if (!f) {
		printf("failed to open %s\n", value_sysfs);
		return 2;
	}
	fread(buf, 1, 4096, f);
	fclose(f);
	*value = (__u16) strtol(buf, NULL, 16);

	ret = sprintf(location_sysfs, "%s/%04x_location", token_sysfs, token);
	if (ret < 0) {
		printf("sprintf location failed\n");
		return 1;
	}
	f = fopen(location_sysfs, "rb");
	if (!f) {
		printf("failed to open %s\n", location_sysfs);
		return 2;
	}
	fread(buf, 1, 4096, f);
	fclose(f);
	*location = (__u16) strtol(buf, NULL, 16);

	if (*location)
		return 0;
	return 2;
}

static int token_is_active(__u16 *location, __u16 *cmpvalue,
			   struct dell_wmi_smbios_buffer *buffer)
{
	int ret;

	buffer->std.cmd_class = CLASS_TOKEN_READ;
	buffer->std.cmd_select = SELECT_TOKEN_STD;
	buffer->std.input[0] = *location;
	ret = run_wmi_smbios_cmd(buffer);
	if (ret != 0 || buffer->std.output[0] != 0)
		return ret;
	ret = (buffer->std.output[1] == *cmpvalue);
	return ret;
}

static int query_token(__u16 token, struct dell_wmi_smbios_buffer *buffer)
{
	__u16 location;
	__u16 value;
	int ret;

	ret = find_token(token, &location, &value);
	if (ret != 0) {
		printf("unable to find token %04x\n", token);
		return 1;
	}
	return token_is_active(&location, &value, buffer);
}

static int activate_token(struct dell_wmi_smbios_buffer *buffer,
		   __u16 token)
{
	__u16 location;
	__u16 value;
	int ret;

	ret = find_token(token, &location, &value);
	if (ret != 0) {
		printf("unable to find token %04x\n", token);
		return 1;
	}
	buffer->std.cmd_class = CLASS_TOKEN_WRITE;
	buffer->std.cmd_select = SELECT_TOKEN_STD;
	buffer->std.input[0] = location;
	buffer->std.input[1] = 1;
	ret = run_wmi_smbios_cmd(buffer);
	return ret;
}

static int query_buffer_size(__u64 *buffer_size)
{
	FILE *f;

	f = fopen(ioctl_devfs, "rb");
	if (!f)
		return -EINVAL;
	fread(buffer_size, sizeof(__u64), 1, f);
	fclose(f);
	return EXIT_SUCCESS;
}

int main(void)
{
	struct dell_wmi_smbios_buffer *buffer;
	int ret;
	__u64 value = 0;

	ret = query_buffer_size(&value);
	if (ret == EXIT_FAILURE || !value) {
		printf("Unable to read buffer size\n");
		goto out;
	}
	printf("Detected required buffer size %lld\n", value);

	buffer = malloc(value);
	if (buffer == NULL) {
		printf("failed to alloc memory for ioctl\n");
		ret = -ENOMEM;
		goto out;
	}
	buffer->length = value;

	/* simple SMBIOS call for looking up TPM info */
	buffer->std.cmd_class = CLASS_FLASH_INTERFACE;
	buffer->std.cmd_select = SELECT_FLASH_INTERFACE;
	buffer->std.input[0] = 2;
	ret = run_wmi_smbios_cmd(buffer);
	if (ret) {
		printf("smbios ioctl failed: %d\n", ret);
		ret = EXIT_FAILURE;
		goto out;
	}
	show_buffer(buffer);

	/* query some tokens */
	ret = query_token(CAPSULE_EN_TOKEN, buffer);
	printf("UEFI Capsule enabled token is: %d\n", ret);
	ret = query_token(CAPSULE_DIS_TOKEN, buffer);
	printf("UEFI Capsule disabled token is: %d\n", ret);

	/* activate UEFI capsule token if disabled */
	if (ret) {
		printf("Enabling UEFI capsule token");
		if (activate_token(buffer, CAPSULE_EN_TOKEN)) {
			printf("activate failed\n");
			ret = -1;
			goto out;
		}
	}
	ret = EXIT_SUCCESS;
out:
	free(buffer);
	return ret;
}