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207 lines
4.7 KiB
207 lines
4.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Sample application for SMBIOS communication over WMI interface |
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* Performs the following: |
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* - Simple cmd_class/cmd_select lookup for TPM information |
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* - Simple query of known tokens and their values |
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* - Simple activation of a token |
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* |
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* Copyright (C) 2017 Dell, Inc. |
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*/ |
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#include <errno.h> |
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#include <fcntl.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <sys/ioctl.h> |
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#include <unistd.h> |
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/* if uapi header isn't installed, this might not yet exist */ |
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#ifndef __packed |
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#define __packed __attribute__((packed)) |
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#endif |
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#include <linux/wmi.h> |
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/* It would be better to discover these using udev, but for a simple |
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* application they're hardcoded |
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*/ |
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static const char *ioctl_devfs = "/dev/wmi/dell-smbios"; |
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static const char *token_sysfs = |
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"/sys/bus/platform/devices/dell-smbios.0/tokens"; |
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static void show_buffer(struct dell_wmi_smbios_buffer *buffer) |
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{ |
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printf("Call: %x/%x [%x,%x,%x,%x]\nResults: [%8x,%8x,%8x,%8x]\n", |
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buffer->std.cmd_class, buffer->std.cmd_select, |
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buffer->std.input[0], buffer->std.input[1], |
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buffer->std.input[2], buffer->std.input[3], |
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buffer->std.output[0], buffer->std.output[1], |
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buffer->std.output[2], buffer->std.output[3]); |
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} |
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static int run_wmi_smbios_cmd(struct dell_wmi_smbios_buffer *buffer) |
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{ |
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int fd; |
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int ret; |
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fd = open(ioctl_devfs, O_NONBLOCK); |
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ret = ioctl(fd, DELL_WMI_SMBIOS_CMD, buffer); |
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close(fd); |
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return ret; |
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} |
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static int find_token(__u16 token, __u16 *location, __u16 *value) |
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{ |
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char location_sysfs[60]; |
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char value_sysfs[57]; |
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char buf[4096]; |
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FILE *f; |
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int ret; |
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ret = sprintf(value_sysfs, "%s/%04x_value", token_sysfs, token); |
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if (ret < 0) { |
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printf("sprintf value failed\n"); |
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return 2; |
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} |
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f = fopen(value_sysfs, "rb"); |
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if (!f) { |
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printf("failed to open %s\n", value_sysfs); |
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return 2; |
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} |
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fread(buf, 1, 4096, f); |
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fclose(f); |
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*value = (__u16) strtol(buf, NULL, 16); |
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ret = sprintf(location_sysfs, "%s/%04x_location", token_sysfs, token); |
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if (ret < 0) { |
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printf("sprintf location failed\n"); |
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return 1; |
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} |
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f = fopen(location_sysfs, "rb"); |
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if (!f) { |
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printf("failed to open %s\n", location_sysfs); |
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return 2; |
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} |
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fread(buf, 1, 4096, f); |
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fclose(f); |
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*location = (__u16) strtol(buf, NULL, 16); |
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if (*location) |
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return 0; |
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return 2; |
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} |
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static int token_is_active(__u16 *location, __u16 *cmpvalue, |
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struct dell_wmi_smbios_buffer *buffer) |
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{ |
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int ret; |
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buffer->std.cmd_class = CLASS_TOKEN_READ; |
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buffer->std.cmd_select = SELECT_TOKEN_STD; |
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buffer->std.input[0] = *location; |
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ret = run_wmi_smbios_cmd(buffer); |
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if (ret != 0 || buffer->std.output[0] != 0) |
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return ret; |
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ret = (buffer->std.output[1] == *cmpvalue); |
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return ret; |
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} |
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static int query_token(__u16 token, struct dell_wmi_smbios_buffer *buffer) |
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{ |
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__u16 location; |
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__u16 value; |
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int ret; |
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ret = find_token(token, &location, &value); |
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if (ret != 0) { |
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printf("unable to find token %04x\n", token); |
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return 1; |
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} |
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return token_is_active(&location, &value, buffer); |
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} |
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static int activate_token(struct dell_wmi_smbios_buffer *buffer, |
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__u16 token) |
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{ |
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__u16 location; |
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__u16 value; |
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int ret; |
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ret = find_token(token, &location, &value); |
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if (ret != 0) { |
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printf("unable to find token %04x\n", token); |
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return 1; |
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} |
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buffer->std.cmd_class = CLASS_TOKEN_WRITE; |
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buffer->std.cmd_select = SELECT_TOKEN_STD; |
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buffer->std.input[0] = location; |
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buffer->std.input[1] = 1; |
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ret = run_wmi_smbios_cmd(buffer); |
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return ret; |
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} |
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static int query_buffer_size(__u64 *buffer_size) |
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{ |
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FILE *f; |
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f = fopen(ioctl_devfs, "rb"); |
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if (!f) |
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return -EINVAL; |
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fread(buffer_size, sizeof(__u64), 1, f); |
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fclose(f); |
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return EXIT_SUCCESS; |
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} |
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int main(void) |
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{ |
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struct dell_wmi_smbios_buffer *buffer; |
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int ret; |
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__u64 value = 0; |
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ret = query_buffer_size(&value); |
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if (ret == EXIT_FAILURE || !value) { |
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printf("Unable to read buffer size\n"); |
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goto out; |
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} |
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printf("Detected required buffer size %lld\n", value); |
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buffer = malloc(value); |
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if (buffer == NULL) { |
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printf("failed to alloc memory for ioctl\n"); |
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ret = -ENOMEM; |
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goto out; |
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} |
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buffer->length = value; |
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/* simple SMBIOS call for looking up TPM info */ |
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buffer->std.cmd_class = CLASS_FLASH_INTERFACE; |
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buffer->std.cmd_select = SELECT_FLASH_INTERFACE; |
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buffer->std.input[0] = 2; |
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ret = run_wmi_smbios_cmd(buffer); |
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if (ret) { |
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printf("smbios ioctl failed: %d\n", ret); |
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ret = EXIT_FAILURE; |
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goto out; |
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} |
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show_buffer(buffer); |
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/* query some tokens */ |
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ret = query_token(CAPSULE_EN_TOKEN, buffer); |
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printf("UEFI Capsule enabled token is: %d\n", ret); |
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ret = query_token(CAPSULE_DIS_TOKEN, buffer); |
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printf("UEFI Capsule disabled token is: %d\n", ret); |
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/* activate UEFI capsule token if disabled */ |
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if (ret) { |
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printf("Enabling UEFI capsule token"); |
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if (activate_token(buffer, CAPSULE_EN_TOKEN)) { |
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printf("activate failed\n"); |
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ret = -1; |
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goto out; |
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} |
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} |
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ret = EXIT_SUCCESS; |
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out: |
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free(buffer); |
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return ret; |
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}
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