diff options
Diffstat (limited to 'tools/wmi/dell-smbios-example.c')
| -rw-r--r-- | tools/wmi/dell-smbios-example.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/tools/wmi/dell-smbios-example.c b/tools/wmi/dell-smbios-example.c new file mode 100644 index 000000000..1f3e7ab14 --- /dev/null +++ b/tools/wmi/dell-smbios-example.c @@ -0,0 +1,207 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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. + */ + +#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; +} |