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Release 4.18 tools/wmi/dell-smbios-example.c

Directory: tools/wmi
/*
 *  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]); }

Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello100100.00%1100.00%
Total100100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello45100.00%1100.00%
Total45100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello225100.00%1100.00%
Total225100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello96100.00%1100.00%
Total96100.00%1100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello66100.00%1100.00%
Total66100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello102100.00%1100.00%
Total102100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello54100.00%1100.00%
Total54100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello231100.00%1100.00%
Total231100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Mario Limonciello968100.00%1100.00%
Total968100.00%1100.00%
Directory: tools/wmi
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