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authorMario Limonciello <mario.limonciello@dell.com>2017-11-01 22:25:37 +0300
committerDarren Hart (VMware) <dvhart@infradead.org>2017-11-04 02:34:00 +0300
commit9d64fc08f6fe59a7d71e84f650dd2c0f080254dd (patch)
tree9c1129c2bb3ef63e0f58e8cb914b38ac43f46a15 /tools/wmi/dell-smbios-example.c
parentf2645fa317b8905b8934f06a0601d5b7fa66aba0 (diff)
downloadlinux-9d64fc08f6fe59a7d71e84f650dd2c0f080254dd.tar.xz
tools/wmi: add a sample for dell smbios communication over WMI
This application uses the character device /dev/wmi/dell-smbios to perform SMBIOS communications from userspace. It offers demonstrations of a few simple tasks: - Running a class/select command - Querying a token value - Activating a token Signed-off-by: Mario Limonciello <mario.limonciello@dell.com> Reviewed-by: Edward O'Callaghan <quasisec@google.com> Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Diffstat (limited to 'tools/wmi/dell-smbios-example.c')
-rw-r--r--tools/wmi/dell-smbios-example.c210
1 files changed, 210 insertions, 0 deletions
diff --git a/tools/wmi/dell-smbios-example.c b/tools/wmi/dell-smbios-example.c
new file mode 100644
index 000000000000..9d3bde081249
--- /dev/null
+++ b/tools/wmi/dell-smbios-example.c
@@ -0,0 +1,210 @@
+/*
+ * 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;
+}