/*
 * Copyright (C) 2021 Richard Hughes <richard@hughsie.com>
 *
 * SPDX-License-Identifier: LGPL-2.1+
 */

#include "config.h"

#include <fwupdplugin.h>

#include <gio/gunixmounts.h>

#include "fu-uefi-backend-linux.h"
#include "fu-uefi-cod-device.h"
#include "fu-uefi-common.h"
#include "fu-uefi-nvram-device.h"

#ifndef HAVE_GIO_2_55_0
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-function"
G_DEFINE_AUTOPTR_CLEANUP_FUNC(GUnixMountEntry, g_unix_mount_free)
#pragma clang diagnostic pop
#endif

struct _FuUefiBackendLinux {
	FuUefiBackend parent_instance;
	gboolean use_rt_set_variable;
};

G_DEFINE_TYPE(FuUefiBackendLinux, fu_uefi_backend_linux, FU_TYPE_UEFI_BACKEND)

/* yes, unsized uint_t */
static guint
fu_uefi_backend_linux_read(const gchar *path, const gchar *filename)
{
	return fu_uefi_read_file_as_uint64(path, filename);
}

static FuUefiDevice *
fu_uefi_backend_linux_device_new(FuUefiBackendLinux *self, const gchar *path)
{
	g_autoptr(FuUefiDevice) dev = NULL;
	g_autofree gchar *fw_class = NULL;
	g_autofree gchar *fw_class_fn = NULL;

	g_return_val_if_fail(path != NULL, NULL);

	/* read values from sysfs */
	fw_class_fn = g_build_filename(path, "fw_class", NULL);
	if (g_file_get_contents(fw_class_fn, &fw_class, NULL, NULL))
		g_strdelimit(fw_class, "\n", '\0');

	/* Create object, assuming a verfmt of NUMBER unless told otherwise by
	 * a quirk entry or metadata.
	 *
	 * The hardware instance is not in the ESRT table and we should really
	 * write the EFI stub to query with FMP -- but we still have not ever
	 * seen a PCIe device with FMP support... */
	dev = g_object_new(fu_uefi_backend_get_device_gtype(FU_UEFI_BACKEND(self)),
			   "fw-class",
			   fw_class,
			   "capsule-flags",
			   fu_uefi_backend_linux_read(path, "capsule_flags"),
			   "kind",
			   fu_uefi_backend_linux_read(path, "fw_type"),
			   "fw-version",
			   fu_uefi_backend_linux_read(path, "fw_version"),
			   "last-attempt-status",
			   fu_uefi_backend_linux_read(path, "last_attempt_status"),
			   "last-attempt-version",
			   fu_uefi_backend_linux_read(path, "last_attempt_version"),
			   "fw-version-lowest",
			   fu_uefi_backend_linux_read(path, "lowest_supported_fw_version"),
			   "fmp-hardware-instance",
			   (guint64)0x0,
			   "version-format",
			   FWUPD_VERSION_FORMAT_NUMBER,
			   NULL);

	/* u-boot for instance */
	if (!self->use_rt_set_variable)
		fu_device_add_private_flag(FU_DEVICE(dev), FU_UEFI_DEVICE_FLAG_NO_RT_SET_VARIABLE);

	/* set ID */
	fu_device_set_physical_id(FU_DEVICE(dev), path);
	return g_steal_pointer(&dev);
}

static gboolean
fu_uefi_backend_linux_check_efivarfs(FuUefiBackendLinux *self, GError **error)
{
	g_autofree gchar *sysfsfwdir = fu_common_get_path(FU_PATH_KIND_SYSFSDIR_FW);
	g_autofree gchar *sysfsefivardir = g_build_filename(sysfsfwdir, "efi", "efivars", NULL);
	g_autoptr(GUnixMountEntry) mount = g_unix_mount_at(sysfsefivardir, NULL);

	/* in the self tests */
	if (g_getenv("FWUPD_UEFI_TEST") != NULL)
		return TRUE;

	if (mount == NULL) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_NOT_FOUND,
			    "%s was not mounted",
			    sysfsefivardir);
		return FALSE;
	}
	if (g_unix_mount_is_readonly(mount)) {
		GType gtype = fu_uefi_backend_get_device_gtype(FU_UEFI_BACKEND(self));
		if (gtype != FU_TYPE_UEFI_COD_DEVICE) {
			g_set_error(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_WRITE,
				    "%s is read only and no CoD",
				    sysfsefivardir);
			return FALSE;
		}

		/* this is fine! just do not use SetVariable... */
		self->use_rt_set_variable = FALSE;
	}

	return TRUE;
}

static gboolean
fu_uefi_backend_linux_coldplug(FuBackend *backend, GError **error)
{
	FuUefiBackendLinux *self = FU_UEFI_BACKEND_LINUX(backend);
	const gchar *fn;
	g_autofree gchar *esrt_entries = NULL;
	g_autofree gchar *esrt_path = NULL;
	g_autofree gchar *sysfsfwdir = NULL;
	g_autoptr(GDir) dir = NULL;

	/* make sure that efivarfs is suitable */
	if (!fu_uefi_backend_linux_check_efivarfs(self, error))
		return FALSE;

	/* get the directory of ESRT entries */
	sysfsfwdir = fu_common_get_path(FU_PATH_KIND_SYSFSDIR_FW);
	esrt_path = g_build_filename(sysfsfwdir, "efi", "esrt", NULL);
	esrt_entries = g_build_filename(esrt_path, "entries", NULL);
	dir = g_dir_open(esrt_entries, 0, error);
	if (dir == NULL)
		return FALSE;

	/* add each device */
	while ((fn = g_dir_read_name(dir)) != NULL) {
		g_autofree gchar *path = g_build_filename(esrt_entries, fn, NULL);
		g_autoptr(FuUefiDevice) dev = fu_uefi_backend_linux_device_new(self, path);
		fu_backend_device_added(backend, FU_DEVICE(dev));
	}

	/* success */
	return TRUE;
}

static gboolean
fu_uefi_backend_linux_check_smbios_enabled(FuContext *ctx, GError **error)
{
	const guint8 *data;
	gsize sz;
	g_autoptr(GBytes) bios_information = fu_context_get_smbios_data(ctx, 0);
	if (bios_information == NULL) {
		const gchar *tmp = g_getenv("FWUPD_DELL_FAKE_SMBIOS");
		if (tmp != NULL)
			return TRUE;
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_NOT_SUPPORTED,
				    "SMBIOS not supported");
		return FALSE;
	}
	data = g_bytes_get_data(bios_information, &sz);
	if (sz < 0x14) {
		g_set_error(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_INVALID_FILE,
			    "offset bigger than size %" G_GSIZE_FORMAT,
			    sz);
		return FALSE;
	}
	if (data[1] < 0x14) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_NOT_SUPPORTED,
				    "SMBIOS 2.3 not supported");
		return FALSE;
	}
	if (!(data[0x13] & (1 << 3))) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_NOT_SUPPORTED,
				    "System does not support UEFI mode");
		return FALSE;
	}
	return TRUE;
}

static gboolean
fu_uefi_backend_linux_setup(FuBackend *backend, GError **error)
{
	g_autoptr(GError) error_local = NULL;

	/* using a pre-cooked SMBIOS */
	if (g_getenv("FWUPD_SYSFSFWDIR") != NULL)
		return TRUE;

	/* check SMBIOS for 'UEFI Specification is supported' */
	if (!fu_uefi_backend_linux_check_smbios_enabled(fu_backend_get_context(backend),
							&error_local)) {
		g_autofree gchar *fw = fu_common_get_path(FU_PATH_KIND_SYSFSDIR_FW);
		g_autofree gchar *fn = g_build_filename(fw, "efi", NULL);
		if (g_file_test(fn, G_FILE_TEST_EXISTS)) {
			g_warning("SMBIOS BIOS Characteristics Extension Byte 2 is invalid -- "
				  "UEFI Specification is unsupported, but %s exists: %s",
				  fn,
				  error_local->message);
			return TRUE;
		}
		g_propagate_error(error, g_steal_pointer(&error_local));
		return FALSE;
	}
	return TRUE;
}

static void
fu_uefi_backend_linux_init(FuUefiBackendLinux *self)
{
	self->use_rt_set_variable = TRUE;
}

static void
fu_uefi_backend_linux_class_init(FuUefiBackendLinuxClass *klass)
{
	FuBackendClass *klass_backend = FU_BACKEND_CLASS(klass);
	klass_backend->coldplug = fu_uefi_backend_linux_coldplug;
	klass_backend->setup = fu_uefi_backend_linux_setup;
}

FuBackend *
fu_uefi_backend_new(FuContext *ctx)
{
	return g_object_new(FU_TYPE_UEFI_BACKEND_LINUX, "name", "uefi", "context", ctx, NULL);
}