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Systemd/src/gudev/gudevclient.c

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/* -*- Mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
*
* Copyright (C) 2008-2010 David Zeuthen <davidz@redhat.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdlib.h>
#include <string.h>
#include "gudevclient.h"
#include "gudevdevice.h"
#include "gudevmarshal.h"
#include "gudevprivate.h"
/**
* SECTION:gudevclient
* @short_description: Query devices and listen to uevents
*
* #GUdevClient is used to query information about devices on a Linux
* system from the Linux kernel and the udev device
* manager.
*
* Device information is retrieved from the kernel (through the
* <literal>sysfs</literal> filesystem) and the udev daemon (through a
* <literal>tmpfs</literal> filesystem) and presented through
* #GUdevDevice objects. This means that no blocking IO ever happens
* (in both cases, we are essentially just reading data from kernel
* memory) and as such there are no asynchronous versions of the
* provided methods.
*
* To get #GUdevDevice objects, use
* g_udev_client_query_by_subsystem(),
* g_udev_client_query_by_device_number(),
* g_udev_client_query_by_device_file(),
* g_udev_client_query_by_sysfs_path(),
* g_udev_client_query_by_subsystem_and_name()
* or the #GUdevEnumerator type.
*
* To listen to uevents, connect to the #GUdevClient::uevent signal.
*/
struct _GUdevClientPrivate
{
GSource *watch_source;
struct udev *udev;
struct udev_monitor *monitor;
gchar **subsystems;
};
enum
{
PROP_0,
PROP_SUBSYSTEMS,
};
enum
{
UEVENT_SIGNAL,
LAST_SIGNAL,
};
static guint signals[LAST_SIGNAL] = { 0 };
G_DEFINE_TYPE (GUdevClient, g_udev_client, G_TYPE_OBJECT)
/* ---------------------------------------------------------------------------------------------------- */
static gboolean
monitor_event (GIOChannel *source,
GIOCondition condition,
gpointer data)
{
GUdevClient *client = (GUdevClient *) data;
GUdevDevice *device;
struct udev_device *udevice;
if (client->priv->monitor == NULL)
goto out;
udevice = udev_monitor_receive_device (client->priv->monitor);
if (udevice == NULL)
goto out;
device = _g_udev_device_new (udevice);
udev_device_unref (udevice);
g_signal_emit (client,
signals[UEVENT_SIGNAL],
0,
g_udev_device_get_action (device),
device);
g_object_unref (device);
out:
return TRUE;
}
static void
g_udev_client_finalize (GObject *object)
{
GUdevClient *client = G_UDEV_CLIENT (object);
if (client->priv->watch_source != NULL)
{
g_source_destroy (client->priv->watch_source);
client->priv->watch_source = NULL;
}
if (client->priv->monitor != NULL)
{
udev_monitor_unref (client->priv->monitor);
client->priv->monitor = NULL;
}
if (client->priv->udev != NULL)
{
udev_unref (client->priv->udev);
client->priv->udev = NULL;
}
g_strfreev (client->priv->subsystems);
if (G_OBJECT_CLASS (g_udev_client_parent_class)->finalize != NULL)
G_OBJECT_CLASS (g_udev_client_parent_class)->finalize (object);
}
static void
g_udev_client_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GUdevClient *client = G_UDEV_CLIENT (object);
switch (prop_id)
{
case PROP_SUBSYSTEMS:
if (client->priv->subsystems != NULL)
g_strfreev (client->priv->subsystems);
client->priv->subsystems = g_strdupv (g_value_get_boxed (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
g_udev_client_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GUdevClient *client = G_UDEV_CLIENT (object);
switch (prop_id)
{
case PROP_SUBSYSTEMS:
g_value_set_boxed (value, client->priv->subsystems);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
g_udev_client_constructed (GObject *object)
{
GUdevClient *client = G_UDEV_CLIENT (object);
GIOChannel *channel;
guint n;
client->priv->udev = udev_new ();
/* connect to event source */
client->priv->monitor = udev_monitor_new_from_netlink (client->priv->udev, "udev");
//g_debug ("ss = %p", client->priv->subsystems);
if (client->priv->subsystems != NULL)
{
/* install subsystem filters to only wake up for certain events */
for (n = 0; client->priv->subsystems[n] != NULL; n++)
{
gchar *subsystem;
gchar *devtype;
gchar *s;
subsystem = g_strdup (client->priv->subsystems[n]);
devtype = NULL;
//g_debug ("s = '%s'", subsystem);
s = strstr (subsystem, "/");
if (s != NULL)
{
devtype = s + 1;
*s = '\0';
}
if (client->priv->monitor != NULL)
udev_monitor_filter_add_match_subsystem_devtype (client->priv->monitor, subsystem, devtype);
g_free (subsystem);
}
/* listen to events, and buffer them */
if (client->priv->monitor != NULL)
{
udev_monitor_enable_receiving (client->priv->monitor);
channel = g_io_channel_unix_new (udev_monitor_get_fd (client->priv->monitor));
client->priv->watch_source = g_io_create_watch (channel, G_IO_IN);
g_io_channel_unref (channel);
g_source_set_callback (client->priv->watch_source, (GSourceFunc) monitor_event, client, NULL);
g_source_attach (client->priv->watch_source, g_main_context_get_thread_default ());
g_source_unref (client->priv->watch_source);
}
else
{
client->priv->watch_source = NULL;
}
}
if (G_OBJECT_CLASS (g_udev_client_parent_class)->constructed != NULL)
G_OBJECT_CLASS (g_udev_client_parent_class)->constructed (object);
}
static void
g_udev_client_class_init (GUdevClientClass *klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
gobject_class->constructed = g_udev_client_constructed;
gobject_class->set_property = g_udev_client_set_property;
gobject_class->get_property = g_udev_client_get_property;
gobject_class->finalize = g_udev_client_finalize;
/**
* GUdevClient:subsystems:
*
* The subsystems to listen for uevents on.
*
* To listen for only a specific DEVTYPE for a given SUBSYSTEM, use
* "subsystem/devtype". For example, to only listen for uevents
* where SUBSYSTEM is usb and DEVTYPE is usb_interface, use
* "usb/usb_interface".
*
* If this property is %NULL, then no events will be reported. If
* it's the empty array, events from all subsystems will be
* reported.
*/
g_object_class_install_property (gobject_class,
PROP_SUBSYSTEMS,
g_param_spec_boxed ("subsystems",
"The subsystems to listen for changes on",
"The subsystems to listen for changes on",
G_TYPE_STRV,
G_PARAM_CONSTRUCT_ONLY |
G_PARAM_READWRITE));
/**
* GUdevClient::uevent:
* @client: The #GUdevClient receiving the event.
* @action: The action for the uevent e.g. "add", "remove", "change", "move", etc.
* @device: Details about the #GUdevDevice the event is for.
*
* Emitted when @client receives an uevent.
*
* This signal is emitted in the
* <link linkend="g-main-context-push-thread-default">thread-default main loop</link>
* of the thread that @client was created in.
*/
signals[UEVENT_SIGNAL] = g_signal_new ("uevent",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GUdevClientClass, uevent),
NULL,
NULL,
g_udev_marshal_VOID__STRING_OBJECT,
G_TYPE_NONE,
2,
G_TYPE_STRING,
G_UDEV_TYPE_DEVICE);
g_type_class_add_private (klass, sizeof (GUdevClientPrivate));
}
static void
g_udev_client_init (GUdevClient *client)
{
client->priv = G_TYPE_INSTANCE_GET_PRIVATE (client,
G_UDEV_TYPE_CLIENT,
GUdevClientPrivate);
}
/**
* g_udev_client_new:
* @subsystems: (array zero-terminated=1) (element-type utf8) (transfer none) (allow-none): A %NULL terminated string array of subsystems to listen for uevents on, %NULL to not listen on uevents at all, or an empty array to listen to uevents on all subsystems. See the documentation for the #GUdevClient:subsystems property for details on this parameter.
*
* Constructs a #GUdevClient object that can be used to query
* information about devices. Connect to the #GUdevClient::uevent
* signal to listen for uevents. Note that signals are emitted in the
* <link linkend="g-main-context-push-thread-default">thread-default main loop</link>
* of the thread that you call this constructor from.
*
* Returns: A new #GUdevClient object. Free with g_object_unref().
*/
GUdevClient *
g_udev_client_new (const gchar * const *subsystems)
{
return G_UDEV_CLIENT (g_object_new (G_UDEV_TYPE_CLIENT, "subsystems", subsystems, NULL));
}
/**
* g_udev_client_query_by_subsystem:
* @client: A #GUdevClient.
* @subsystem: (allow-none): The subsystem to get devices for or %NULL to get all devices.
*
* Gets all devices belonging to @subsystem.
*
* Returns: (element-type GUdevDevice) (transfer full): A list of #GUdevDevice objects. The caller should free the result by using g_object_unref() on each element in the list and then g_list_free() on the list.
*/
GList *
g_udev_client_query_by_subsystem (GUdevClient *client,
const gchar *subsystem)
{
struct udev_enumerate *enumerate;
struct udev_list_entry *l, *devices;
GList *ret;
g_return_val_if_fail (G_UDEV_IS_CLIENT (client), NULL);
ret = NULL;
/* prepare a device scan */
enumerate = udev_enumerate_new (client->priv->udev);
/* filter for subsystem */
if (subsystem != NULL)
udev_enumerate_add_match_subsystem (enumerate, subsystem);
/* retrieve the list */
udev_enumerate_scan_devices (enumerate);
/* add devices to the list */
devices = udev_enumerate_get_list_entry (enumerate);
for (l = devices; l != NULL; l = udev_list_entry_get_next (l))
{
struct udev_device *udevice;
GUdevDevice *device;
udevice = udev_device_new_from_syspath (udev_enumerate_get_udev (enumerate),
udev_list_entry_get_name (l));
if (udevice == NULL)
continue;
device = _g_udev_device_new (udevice);
udev_device_unref (udevice);
ret = g_list_prepend (ret, device);
}
udev_enumerate_unref (enumerate);
ret = g_list_reverse (ret);
return ret;
}
/**
* g_udev_client_query_by_device_number:
* @client: A #GUdevClient.
* @type: A value from the #GUdevDeviceType enumeration.
* @number: A device number.
*
* Looks up a device for a type and device number.
*
* Returns: (transfer full): A #GUdevDevice object or %NULL if the device was not found. Free with g_object_unref().
*/
GUdevDevice *
g_udev_client_query_by_device_number (GUdevClient *client,
GUdevDeviceType type,
GUdevDeviceNumber number)
{
struct udev_device *udevice;
GUdevDevice *device;
g_return_val_if_fail (G_UDEV_IS_CLIENT (client), NULL);
device = NULL;
udevice = udev_device_new_from_devnum (client->priv->udev, type, number);
if (udevice == NULL)
goto out;
device = _g_udev_device_new (udevice);
udev_device_unref (udevice);
out:
return device;
}
/**
* g_udev_client_query_by_device_file:
* @client: A #GUdevClient.
* @device_file: A device file.
*
* Looks up a device for a device file.
*
* Returns: (transfer full): A #GUdevDevice object or %NULL if the device was not found. Free with g_object_unref().
*/
GUdevDevice *
g_udev_client_query_by_device_file (GUdevClient *client,
const gchar *device_file)
{
struct stat stat_buf;
GUdevDevice *device;
g_return_val_if_fail (G_UDEV_IS_CLIENT (client), NULL);
g_return_val_if_fail (device_file != NULL, NULL);
device = NULL;
if (stat (device_file, &stat_buf) != 0)
goto out;
if (stat_buf.st_rdev == 0)
goto out;
if (S_ISBLK (stat_buf.st_mode))
device = g_udev_client_query_by_device_number (client, G_UDEV_DEVICE_TYPE_BLOCK, stat_buf.st_rdev);
else if (S_ISCHR (stat_buf.st_mode))
device = g_udev_client_query_by_device_number (client, G_UDEV_DEVICE_TYPE_CHAR, stat_buf.st_rdev);
out:
return device;
}
/**
* g_udev_client_query_by_sysfs_path:
* @client: A #GUdevClient.
* @sysfs_path: A sysfs path.
*
* Looks up a device for a sysfs path.
*
* Returns: (transfer full): A #GUdevDevice object or %NULL if the device was not found. Free with g_object_unref().
*/
GUdevDevice *
g_udev_client_query_by_sysfs_path (GUdevClient *client,
const gchar *sysfs_path)
{
struct udev_device *udevice;
GUdevDevice *device;
g_return_val_if_fail (G_UDEV_IS_CLIENT (client), NULL);
g_return_val_if_fail (sysfs_path != NULL, NULL);
device = NULL;
udevice = udev_device_new_from_syspath (client->priv->udev, sysfs_path);
if (udevice == NULL)
goto out;
device = _g_udev_device_new (udevice);
udev_device_unref (udevice);
out:
return device;
}
/**
* g_udev_client_query_by_subsystem_and_name:
* @client: A #GUdevClient.
* @subsystem: A subsystem name.
* @name: The name of the device.
*
* Looks up a device for a subsystem and name.
*
* Returns: (transfer full): A #GUdevDevice object or %NULL if the device was not found. Free with g_object_unref().
*/
GUdevDevice *
g_udev_client_query_by_subsystem_and_name (GUdevClient *client,
const gchar *subsystem,
const gchar *name)
{
struct udev_device *udevice;
GUdevDevice *device;
g_return_val_if_fail (G_UDEV_IS_CLIENT (client), NULL);
g_return_val_if_fail (subsystem != NULL, NULL);
g_return_val_if_fail (name != NULL, NULL);
device = NULL;
udevice = udev_device_new_from_subsystem_sysname (client->priv->udev, subsystem, name);
if (udevice == NULL)
goto out;
device = _g_udev_device_new (udevice);
udev_device_unref (udevice);
out:
return device;
}
struct udev *
_g_udev_client_get_udev (GUdevClient *client)
{
g_return_val_if_fail (G_UDEV_IS_CLIENT (client), NULL);
return client->priv->udev;
}