/*
 * Copyright (C) 2012 Intel Corporation.
 * Copyright (C) 2017 Google, Inc.
 * Copyright (C) 2017 Richard Hughes <richard@hughsie.com>
 *
 * SPDX-License-Identifier: LGPL-2.1+
 */

#include "config.h"

#include <fwupdplugin.h>

#include <errno.h>
#include <fcntl.h>
#include <linux/mei.h>
#include <string.h>
#include <sys/ioctl.h>

typedef struct {
	uuid_le guid;
	guint buf_size;
	guchar prot_ver;
	gint fd;
} mei_context;

static void
mei_context_free(mei_context *cl)
{
	if (cl->fd != -1)
		close(cl->fd);
	g_free(cl);
}

static gboolean
mei_context_new(mei_context *ctx, const uuid_le *guid, guchar req_protocol_version, GError **error)
{
	gint result;
	struct mei_client *cl;
	struct mei_connect_client_data data;

	ctx->fd = open("/dev/mei0", O_RDWR);
	if (ctx->fd == -1 && errno == ENOENT)
		ctx->fd = open("/dev/mei", O_RDWR);
	if (ctx->fd == -1) {
		if (errno == ENOENT) {
			g_set_error(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_NOT_FOUND,
				    "Unable to find a ME interface");
		} else {
			g_set_error_literal(error,
					    FWUPD_ERROR,
					    FWUPD_ERROR_NOT_FOUND,
					    "Cannot open /dev/mei0");
		}
		return FALSE;
	}
	memcpy(&ctx->guid, guid, sizeof(*guid));
	memset(&data, 0, sizeof(data));
	memcpy(&data.in_client_uuid, &ctx->guid, sizeof(ctx->guid));
	result = ioctl(ctx->fd, IOCTL_MEI_CONNECT_CLIENT, &data);
	if (result != 0) {
		g_set_error(error, FWUPD_ERROR, FWUPD_ERROR_NOT_SUPPORTED, "ME refused connection");
		return FALSE;
	}
	cl = &data.out_client_properties;
	if ((req_protocol_version > 0) && (cl->protocol_version != req_protocol_version)) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_NOT_SUPPORTED,
			    "Intel MEI protocol version not supported %i",
			    cl->protocol_version);
		return FALSE;
	}

	ctx->buf_size = cl->max_msg_length;
	ctx->prot_ver = cl->protocol_version;
	return TRUE;
}

static gboolean
mei_recv_msg(mei_context *ctx,
	     guchar *buffer,
	     gssize len,
	     guint32 *readsz,
	     unsigned long timeout,
	     GError **error)
{
	gssize rc;
	rc = read(ctx->fd, buffer, len);
	if (rc < 0) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_READ,
			    "read failed with status %zd %s",
			    rc,
			    strerror(errno));
		return FALSE;
	}
	if (readsz != NULL)
		*readsz = rc;
	return TRUE;
}

static gboolean
mei_send_msg(mei_context *ctx,
	     const guchar *buffer,
	     gssize len,
	     unsigned long timeout,
	     GError **error)
{
	struct timeval tv;
	gssize written;
	gssize rc;
	fd_set set;

	tv.tv_sec = timeout / 1000;
	tv.tv_usec = (timeout % 1000) * 1000000;

	written = write(ctx->fd, buffer, len);
	if (written < 0) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_WRITE,
			    "write failed with status %zd %s",
			    written,
			    strerror(errno));
		return FALSE;
	}
	if (written != len) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_WRITE,
			    "only wrote %" G_GSSIZE_FORMAT " of %" G_GSSIZE_FORMAT,
			    written,
			    len);
		return FALSE;
	}

	FD_ZERO(&set);
	FD_SET(ctx->fd, &set);
	rc = select(ctx->fd + 1, &set, NULL, NULL, &tv);
	if (rc > 0 && FD_ISSET(ctx->fd, &set))
		return TRUE;

	/* timed out */
	if (rc == 0) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_WRITE,
			    "write failed on timeout with status");
		return FALSE;
	}

	/* rc < 0 */
	g_set_error(error,
		    FWUPD_ERROR,
		    FWUPD_ERROR_WRITE,
		    "write failed on select with status %zd",
		    rc);
	return FALSE;
}

/***************************************************************************
 * Intel Advanced Management Technology ME Client
 ***************************************************************************/

#define AMT_MAJOR_VERSION 1
#define AMT_MINOR_VERSION 1

#define AMT_STATUS_SUCCESS		  0x0
#define AMT_STATUS_INTERNAL_ERROR	  0x1
#define AMT_STATUS_NOT_READY		  0x2
#define AMT_STATUS_INVALID_AMT_MODE	  0x3
#define AMT_STATUS_INVALID_MESSAGE_LENGTH 0x4

#define AMT_STATUS_HOST_IF_EMPTY_RESPONSE 0x4000
#define AMT_STATUS_SDK_RESOURCES	  0x1004

#define AMT_BIOS_VERSION_LEN   65
#define AMT_VERSIONS_NUMBER    50
#define AMT_UNICODE_STRING_LEN 20

struct amt_unicode_string {
	guint16 length;
	char string[AMT_UNICODE_STRING_LEN];
} __attribute__((packed));

struct amt_version_type {
	struct amt_unicode_string description;
	struct amt_unicode_string version;
} __attribute__((packed));

struct amt_version {
	guint8 major;
	guint8 minor;
} __attribute__((packed));

struct amt_code_versions {
	guint8 bios[AMT_BIOS_VERSION_LEN];
	guint32 count;
	struct amt_version_type versions[AMT_VERSIONS_NUMBER];
} __attribute__((packed));

struct amt_provisioning_state {
	guint8 bios[AMT_BIOS_VERSION_LEN];
	guint32 count;
	guint8 state;
} __attribute__((packed));

/***************************************************************************
 * Intel Advanced Management Technology Host Interface
 ***************************************************************************/

struct amt_host_if_msg_header {
	struct amt_version version;
	guint16 _reserved;
	guint32 command;
	guint32 length;
} __attribute__((packed));

struct amt_host_if_resp_header {
	struct amt_host_if_msg_header header;
	guint32 status;
	guchar data[0];
} __attribute__((packed));

#define AMT_HOST_IF_CODE_VERSIONS_REQUEST  0x0400001A
#define AMT_HOST_IF_CODE_VERSIONS_RESPONSE 0x0480001A

const struct amt_host_if_msg_header CODE_VERSION_REQ = {
    .version = {AMT_MAJOR_VERSION, AMT_MINOR_VERSION},
    ._reserved = 0,
    .command = AMT_HOST_IF_CODE_VERSIONS_REQUEST,
    .length = 0};

#define AMT_HOST_IF_PROVISIONING_MODE_REQUEST  0x04000008
#define AMT_HOST_IF_PROVISIONING_MODE_RESPONSE 0x04800008

const struct amt_host_if_msg_header PROVISIONING_MODE_REQUEST = {
    .version = {AMT_MAJOR_VERSION, AMT_MINOR_VERSION},
    ._reserved = 0,
    .command = AMT_HOST_IF_PROVISIONING_MODE_REQUEST,
    .length = 0};

#define AMT_HOST_IF_PROVISIONING_STATE_REQUEST	0x04000011
#define AMT_HOST_IF_PROVISIONING_STATE_RESPONSE 0x04800011

const struct amt_host_if_msg_header PROVISIONING_STATE_REQUEST = {
    .version = {AMT_MAJOR_VERSION, AMT_MINOR_VERSION},
    ._reserved = 0,
    .command = AMT_HOST_IF_PROVISIONING_STATE_REQUEST,
    .length = 0};

struct amt_host_if {
	mei_context mei_cl;
};

static gboolean
amt_verify_code_versions(const struct amt_host_if_resp_header *resp, GError **error)
{
	struct amt_code_versions *code_ver = (struct amt_code_versions *)resp->data;
	gsize code_ver_len = resp->header.length - sizeof(guint32);
	guint32 ver_type_cnt = code_ver_len - sizeof(code_ver->bios) - sizeof(code_ver->count);
	if (code_ver->count != ver_type_cnt / sizeof(struct amt_version_type)) {
		g_set_error_literal(error, FWUPD_ERROR, FWUPD_ERROR_INTERNAL, "invalid offset");
		return FALSE;
	}
	for (guint32 i = 0; i < code_ver->count; i++) {
		guint32 len = code_ver->versions[i].description.length;
		if (len > AMT_UNICODE_STRING_LEN) {
			g_set_error_literal(error,
					    FWUPD_ERROR,
					    FWUPD_ERROR_INTERNAL,
					    "string too large");
			return FALSE;
		}
		len = code_ver->versions[i].version.length;
		if (code_ver->versions[i].version.string[len] != '\0' ||
		    len != strlen(code_ver->versions[i].version.string)) {
			g_set_error_literal(error,
					    FWUPD_ERROR,
					    FWUPD_ERROR_INTERNAL,
					    "string was invalid size");
			return FALSE;
		}
	}
	return TRUE;
}

static gboolean
amt_status_set_error(guint32 status, GError **error)
{
	if (status == AMT_STATUS_SUCCESS)
		return TRUE;
	if (status == AMT_STATUS_INTERNAL_ERROR) {
		g_set_error_literal(error, FWUPD_ERROR, FWUPD_ERROR_INTERNAL, "internal error");
		return FALSE;
	}
	if (status == AMT_STATUS_NOT_READY) {
		g_set_error_literal(error, FWUPD_ERROR, FWUPD_ERROR_INTERNAL, "not ready");
		return FALSE;
	}
	if (status == AMT_STATUS_INVALID_AMT_MODE) {
		g_set_error_literal(error, FWUPD_ERROR, FWUPD_ERROR_INTERNAL, "invalid AMT mode");
		return FALSE;
	}
	if (status == AMT_STATUS_INVALID_MESSAGE_LENGTH) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_INTERNAL,
				    "invalid message length");
		return FALSE;
	}
	if (status == AMT_STATUS_HOST_IF_EMPTY_RESPONSE) {
		g_set_error(error, FWUPD_ERROR, FWUPD_ERROR_NOT_SUPPORTED, "Intel AMT is disabled");
		return FALSE;
	}
	g_set_error_literal(error, FWUPD_ERROR, FWUPD_ERROR_INTERNAL, "unknown error");
	return FALSE;
}

static gboolean
amt_host_if_call(mei_context *mei_cl,
		 const guchar *command,
		 gssize command_sz,
		 guint8 **read_buf,
		 guint32 rcmd,
		 guint expected_sz,
		 unsigned long send_timeout,
		 GError **error)
{
	guint32 in_buf_sz;
	guint32 out_buf_sz;
	struct amt_host_if_resp_header *msg_hdr;

	in_buf_sz = mei_cl->buf_size;
	*read_buf = (guint8 *)g_malloc0(in_buf_sz);
	msg_hdr = (struct amt_host_if_resp_header *)*read_buf;

	if (!mei_send_msg(mei_cl, command, command_sz, send_timeout, error))
		return FALSE;
	if (!mei_recv_msg(mei_cl, *read_buf, in_buf_sz, &out_buf_sz, 2000, error))
		return FALSE;
	if (out_buf_sz <= 0) {
		g_set_error_literal(error, FWUPD_ERROR, FWUPD_ERROR_READ, "empty response");
		return FALSE;
	}
	if (expected_sz && expected_sz != out_buf_sz) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_WRITE,
			    "expected %u but got %" G_GUINT32_FORMAT,
			    expected_sz,
			    out_buf_sz);
		return FALSE;
	}
	if (!amt_status_set_error(msg_hdr->status, error))
		return FALSE;
	if (out_buf_sz < sizeof(struct amt_host_if_resp_header)) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_READ,
				    "invalid response: too small");
		return FALSE;
	}
	if (out_buf_sz != (msg_hdr->header.length + sizeof(struct amt_host_if_msg_header))) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_READ,
				    "invalid response: headerlen");
		return FALSE;
	}
	if (msg_hdr->header.command != rcmd) {
		g_set_error_literal(error, FWUPD_ERROR, FWUPD_ERROR_READ, "invalid response: rcmd");
		return FALSE;
	}
	if (msg_hdr->header._reserved != 0) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_READ,
				    "invalid response: reserved");
		return FALSE;
	}
	if (msg_hdr->header.version.major != AMT_MAJOR_VERSION ||
	    msg_hdr->header.version.minor < AMT_MINOR_VERSION) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_READ,
				    "invalid response: version");
		return FALSE;
	}
	return TRUE;
}

static gboolean
amt_get_provisioning_state(mei_context *mei_cl, guint8 *state, GError **error)
{
	g_autofree struct amt_host_if_resp_header *response = NULL;
	if (!amt_host_if_call(mei_cl,
			      (const guchar *)&PROVISIONING_STATE_REQUEST,
			      sizeof(PROVISIONING_STATE_REQUEST),
			      (guint8 **)&response,
			      AMT_HOST_IF_PROVISIONING_STATE_RESPONSE,
			      0,
			      5000,
			      error)) {
		g_prefix_error(error, "unable to get provisioning state: ");
		return FALSE;
	}
	*state = response->data[0];
	return TRUE;
}

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-function"
G_DEFINE_AUTOPTR_CLEANUP_FUNC(mei_context, mei_context_free)
#pragma clang diagnostic pop

static FuDevice *
fu_plugin_amt_create_device(FuPlugin *plugin, GError **error)
{
	guint8 state;
	struct amt_code_versions ver;
	fwupd_guid_t uu;
	g_autofree gchar *guid_buf = NULL;
	g_autofree struct amt_host_if_resp_header *response = NULL;
	g_autoptr(FuDevice) dev = NULL;
	g_autoptr(GString) version_bl = g_string_new(NULL);
	g_autoptr(GString) version_fw = g_string_new(NULL);
	g_autoptr(mei_context) ctx = g_new0(mei_context, 1);

	const uuid_le MEI_IAMTHIF =
	    UUID_LE(0x12f80028, 0xb4b7, 0x4b2d, 0xac, 0xa8, 0x46, 0xe0, 0xff, 0x65, 0x81, 0x4c);

	/* create context */
	if (!mei_context_new(ctx, &MEI_IAMTHIF, 0, error))
		return NULL;

	/* check version */
	if (!amt_host_if_call(ctx,
			      (const guchar *)&CODE_VERSION_REQ,
			      sizeof(CODE_VERSION_REQ),
			      (guint8 **)&response,
			      AMT_HOST_IF_CODE_VERSIONS_RESPONSE,
			      0,
			      5000,
			      error)) {
		g_prefix_error(error, "Failed to check version: ");
		return NULL;
	}
	if (!amt_verify_code_versions(response, error)) {
		g_prefix_error(error, "failed to verify code versions: ");
		return NULL;
	}
	memcpy(&ver, response->data, sizeof(struct amt_code_versions));

	dev = fu_device_new_with_context(fu_plugin_get_context(plugin));
	fu_device_set_id(dev, "/dev/mei0");
	fu_device_set_vendor(dev, "Intel Corporation");
	fu_device_add_flag(dev, FWUPD_DEVICE_FLAG_INTERNAL);
	fu_device_add_icon(dev, "computer");
	fu_device_add_parent_guid(dev, "main-system-firmware");
	if (!amt_get_provisioning_state(ctx, &state, error))
		return NULL;
	switch (state) {
	case 0:
		fu_device_set_name(dev, "Intel AMT [unprovisioned]");
		break;
	case 1:
		fu_device_set_name(dev, "Intel AMT [being provisioned]");
		break;
	case 2:
		fu_device_set_name(dev, "Intel AMT [provisioned]");
		break;
	default:
		fu_device_set_name(dev, "Intel AMT [unknown]");
		break;
	}
	fu_device_set_summary(dev,
			      "Hardware and firmware technology for remote "
			      "out-of-band management");

	/* add guid */
	memcpy(&uu, &ctx->guid, 16);
	guid_buf = fwupd_guid_to_string((const fwupd_guid_t *)&uu, FWUPD_GUID_FLAG_NONE);
	fu_device_add_guid(dev, guid_buf);

	/* get version numbers */
	for (guint i = 0; i < ver.count; i++) {
		if (g_strcmp0(ver.versions[i].description.string, "AMT") == 0) {
			g_string_append(version_fw, ver.versions[i].version.string);
			continue;
		}
		if (g_strcmp0(ver.versions[i].description.string, "Recovery Version") == 0) {
			g_string_append(version_bl, ver.versions[i].version.string);
			continue;
		}
		if (g_strcmp0(ver.versions[i].description.string, "Build Number") == 0) {
			g_string_append_printf(version_fw, ".%s", ver.versions[i].version.string);
			continue;
		}
		if (g_strcmp0(ver.versions[i].description.string, "Recovery Build Num") == 0) {
			g_string_append_printf(version_bl, ".%s", ver.versions[i].version.string);
			continue;
		}
	}
	fu_device_set_version_format(dev, FWUPD_VERSION_FORMAT_INTEL_ME);
	if (version_fw->len > 0)
		fu_device_set_version(dev, version_fw->str);
	if (version_bl->len > 0)
		fu_device_set_version_bootloader(dev, version_bl->str);

	return g_steal_pointer(&dev);
}

void
fu_plugin_init(FuPlugin *plugin)
{
	fu_plugin_set_build_hash(plugin, FU_BUILD_HASH);
}

gboolean
fu_plugin_coldplug(FuPlugin *plugin, GError **error)
{
	g_autoptr(FuDevice) dev = NULL;
	dev = fu_plugin_amt_create_device(plugin, error);
	if (dev == NULL)
		return FALSE;
	fu_plugin_device_add(plugin, dev);
	return TRUE;
}