fwupd/plugins/modem-manager/fu-mm-utils.c

/*
 * Copyright (C) 2019 Aleksander Morgado <aleksander@aleksander.es>
 *
 * SPDX-License-Identifier: LGPL-2.1+
 */

#include "config.h"

#include <fwupdplugin.h>
#include <gio/gio.h>

#include "fu-mm-utils.h"

static gchar *
find_device_bus_subsystem (GUdevDevice *device)
{
	g_autoptr(GUdevDevice) iter = NULL;

	iter = g_object_ref (device);
	while (iter != NULL) {
		g_autoptr(GUdevDevice) next = NULL;
		const gchar *subsys;

		/* stop search as soon as we find a parent object
		 * of one of the bus subsystems supported in
		 * ModemManager */
		subsys = g_udev_device_get_subsystem (iter);
		if ((g_strcmp0 (subsys, "usb") == 0)      ||
		    (g_strcmp0 (subsys, "pcmcia") == 0)   ||
		    (g_strcmp0 (subsys, "pci") == 0)      ||
		    (g_strcmp0 (subsys, "platform") == 0) ||
		    (g_strcmp0 (subsys, "pnp") == 0)      ||
		    (g_strcmp0 (subsys, "sdio") == 0)) {
			return g_ascii_strup (subsys, -1);
		}

		next = g_udev_device_get_parent (iter);
		g_set_object (&iter, next);
	}

	/* no more parents to check */
	return NULL;
}

gboolean
fu_mm_utils_get_udev_port_info (GUdevDevice	 *device,
				gchar		**out_device_bus,
				gchar		**out_device_sysfs_path,
				gint		 *out_port_usb_ifnum,
				GError		**error)
{
	gint port_usb_ifnum = -1;
	g_autoptr(GUdevDevice) parent = NULL;
	g_autofree gchar *device_sysfs_path = NULL;
	g_autofree gchar *device_bus = NULL;

	/* lookup the main bus the device is in; for supported devices it will
	 * usually be either 'PCI' or 'USB' */
	device_bus = find_device_bus_subsystem (device);
	if (device_bus == NULL) {
		g_set_error (error,
			     G_IO_ERROR,
			     G_IO_ERROR_NOT_FOUND,
			     "failed to lookup device info: bus not found");
		return FALSE;
	}

	if (g_strcmp0 (device_bus, "USB") == 0) {
		/* ID_USB_INTERFACE_NUM is set on the port device itself */
		const gchar *aux = g_udev_device_get_property (device, "ID_USB_INTERFACE_NUM");
		if (aux != NULL)
			port_usb_ifnum = (guint16) g_ascii_strtoull (aux, NULL, 16);

		/* we need to traverse all parents of the give udev device until we find
		 * the first 'usb_device' reported, which is the GUdevDevice associated with
		 * the full USB device (i.e. all ports of the same device).
		 */
		parent = g_udev_device_get_parent (device);
		while (parent != NULL) {
			g_autoptr(GUdevDevice) next = NULL;

			if (g_strcmp0 (g_udev_device_get_devtype (parent), "usb_device") == 0) {
				device_sysfs_path = g_strdup (g_udev_device_get_sysfs_path (parent));
				break;
			}

			/* check next parent */
			next = g_udev_device_get_parent (parent);
			g_set_object (&parent, next);
		}
	} else if (g_strcmp0 (device_bus, "PCI") == 0) {
		/* the first parent in the 'pci' subsystem is our physical device */
		parent = g_udev_device_get_parent (device);
		while (parent != NULL) {
			g_autoptr(GUdevDevice) next = NULL;

			if (g_strcmp0 (g_udev_device_get_subsystem (parent), "pci") == 0) {
				device_sysfs_path = g_strdup (g_udev_device_get_sysfs_path (parent));
				break;
			}

			/* check next parent */
			next = g_udev_device_get_parent (parent);
			g_set_object (&parent, next);
		}
	} else {
		/* other subsystems, we don't support firmware upgrade for those */
		g_set_error (error,
			     G_IO_ERROR,
			     G_IO_ERROR_NOT_SUPPORTED,
			     "device bus unsupported: %s", device_bus);
		return FALSE;
	}

	if (device_sysfs_path == NULL) {
		g_set_error (error,
			     G_IO_ERROR,
			     G_IO_ERROR_NOT_FOUND,
			     "failed to lookup device info: physical device not found");
		return FALSE;
	}

	if (out_port_usb_ifnum != NULL)
		*out_port_usb_ifnum = port_usb_ifnum;
	if (out_device_sysfs_path != NULL)
		*out_device_sysfs_path = g_steal_pointer (&device_sysfs_path);
	if (out_device_bus != NULL)
		*out_device_bus = g_steal_pointer (&device_bus);
	return TRUE;
}

gboolean
fu_mm_utils_get_port_info (const gchar	 *path,
			   gchar	**out_device_bus,
			   gchar	**out_device_sysfs_path,
			   gint		 *out_port_usb_ifnum,
			   GError	**error)
{
	g_autoptr(GUdevClient) client = NULL;
	g_autoptr(GUdevDevice) dev = NULL;

	client = g_udev_client_new (NULL);
	dev = g_udev_client_query_by_device_file (client, path);
	if (dev == NULL) {
		g_set_error (error,
			     G_IO_ERROR,
			     G_IO_ERROR_NOT_FOUND,
			     "failed to lookup device by path");
		return FALSE;
	}

	return fu_mm_utils_get_udev_port_info (dev, out_device_bus, out_device_sysfs_path, out_port_usb_ifnum, error);
}