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authordavid@fubar.dk <david@fubar.dk>2003-12-08 09:19:19 -0800
committerGreg KH <gregkh@suse.de>2005-04-26 21:13:06 -0700
commit5aebfbcb62614fc2bf2b1579d62e3fe272c6751a (patch)
treeafe2093652343ee02e95880d25cf3b3e48779c74
parent3d150dfb28efbaf0b25f154fb8955c47d606c3d5 (diff)
[PATCH] D-BUS patch for udev-008
Attached is a patch against udev-008 to send out a D-BUS message when a device node is added or removed. Using D-BUS lingo, udev acquires the org.kernel.udev service and sends out a NodeCreated or NodeDeleted signal on the org.kernel.udev.NodeMonitor interface. Each signal carries two parameters: the node in question and the corresponding sysfs path. [Note: the D-BUS concepts of service, interface, object can be a bit confusing at first glance] An example program listening for these messages looks like this #!/usr/bin/python import dbus import gtk def udev_signal_received(dbus_iface, member, service, object_path, message): [filename, sysfs_path] = message.get_args_list() if member=='NodeCreated': print 'Node %s created for %s'%(filename, sysfs_path) elif member=='NodeDeleted': print 'Node %s deleted for %s'%(filename, sysfs_path) def main(): bus = dbus.Bus(dbus.Bus.TYPE_SYSTEM) bus.add_signal_receiver(udev_signal_received, 'org.kernel.udev.NodeMonitor', # interface 'org.kernel.udev', # service '/org/kernel/udev/NodeMonitor') # object gtk.mainloop() if __name__ == '__main__': main() and this is the output when hot-plugging some usb-storage. [david@laptop udev-008]$ ~/node_monitor.py Node /udev/sda created for /block/sda Node /udev/sda1 created for /block/sda/sda1 Node /udev/sda1 deleted for /block/sda/sda1 Node /udev/sda deleted for /block/sda The patch requires D-BUS 0.20 or later while the python example program requires D-BUS from CVS as I only recently applied a patch against the python bindings.
-rw-r--r--Makefile29
-rw-r--r--TODO1
-rw-r--r--udev-add.c42
-rw-r--r--udev-remove.c41
-rw-r--r--udev.c64
-rw-r--r--udev.h9
-rw-r--r--udev_sysbus_policy.conf23
7 files changed, 206 insertions, 3 deletions
diff --git a/Makefile b/Makefile
index aa1d45bdb7..c50bd04824 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,10 @@
# Leave this set to `false' for production use.
DEBUG = false
+# Set the following to `true' to make udev emit a D-BUS signal when a
+# new node is created.
+USE_DBUS = true
+
ROOT = udev
VERSION = 008_bk
@@ -34,6 +38,7 @@ etcdir = ${prefix}/etc
sbindir = ${exec_prefix}/sbin
mandir = ${prefix}/usr/share/man
hotplugdir = ${etcdir}/hotplug.d/default
+dbusdir = ${etcdir}/dbus-1/system.d
configdir = ${etcdir}/udev/
srcdir = .
@@ -138,6 +143,13 @@ endif
CFLAGS += -I$(PWD)/libsysfs
+ifeq ($(USE_DBUS), true)
+ CFLAGS += -DUSE_DBUS
+ CFLAGS += $(shell pkg-config --cflags dbus-1)
+ LIB_OBJS += $(shell pkg-config --libs-only-l dbus-1)
+endif
+
+
all: $(ROOT)
@for target in $(EXTRAS) ; do \
echo $$target ; \
@@ -240,7 +252,20 @@ small_release: $(DISTFILES) clean
@echo "Built $(RELEASE_NAME).tar.gz"
-install: all
+ifeq ($(USE_DBUS), true)
+install-dbus-policy:
+ $(INSTALL) -d $(DESTDIR)$(dbusdir)
+ $(INSTALL_DATA) udev_sysbus_policy.conf $(DESTDIR)$(dbusdir)
+uninstall-dbus-policy:
+ - rm $(DESTDIR)$(dbusdir)/udev_sysbus_policy.conf
+else
+install-dbus-policy:
+ -
+uninstall-dbus-policy:
+ -
+endif
+
+install: install-dbus-policy all
$(INSTALL) -d $(DESTDIR)$(udevdir)
$(INSTALL) -d $(DESTDIR)$(configdir)
$(INSTALL) -d $(DESTDIR)$(hotplugdir)
@@ -257,7 +282,7 @@ install: all
-C $$target $@ ; \
done ; \
-uninstall:
+uninstall: uninstall-dbus-policy
- rm $(hotplugdir)/udev.hotplug
- rm $(configdir)/udev.permissions
- rm $(configdir)/udev.rules
diff --git a/TODO b/TODO
index d5cc9194e6..e227834f36 100644
--- a/TODO
+++ b/TODO
@@ -21,7 +21,6 @@ greg@kroah.com
will have an upgrade path.
- do early boot logic (putting udev into initramfs, handle pivot-root,
etc.)
-- add hooks to call D-BUS when new node is created or removed
- lots of other stuff...
- actually use the BUS= value to determine where the LABEL rule should look
(right now it's ignored, and we only look in the current sysfs directory.)
diff --git a/udev-add.c b/udev-add.c
index ddf432bbc7..174331fade 100644
--- a/udev-add.c
+++ b/udev-add.c
@@ -100,6 +100,42 @@ static int create_path(char *file)
return 0;
}
+#ifdef USE_DBUS
+/** Send out a signal that a device node is created
+ *
+ * @param dev udevice object
+ * @param path Sysfs path of device
+ */
+static void sysbus_send_create(struct udevice *dev, const char *path)
+{
+ char filename[255];
+ DBusMessage* message;
+ DBusMessageIter iter;
+
+ if (sysbus_connection == NULL)
+ return;
+
+ strncpy(filename, udev_root, sizeof(filename));
+ strncat(filename, dev->name, sizeof(filename));
+
+ /* object, interface, member */
+ message = dbus_message_new_signal("/org/kernel/udev/NodeMonitor",
+ "org.kernel.udev.NodeMonitor",
+ "NodeCreated");
+
+ dbus_message_iter_init(message, &iter);
+ dbus_message_iter_append_string(&iter, filename);
+ dbus_message_iter_append_string(&iter, path);
+
+ if ( !dbus_connection_send(sysbus_connection, message, NULL) )
+ dbg("error sending d-bus signal");
+
+ dbus_message_unref(message);
+
+ dbus_connection_flush(sysbus_connection);
+}
+#endif /* USE_DBUS */
+
/*
* we possibly want to add some symlinks here
* only numeric owner/group id's are supported
@@ -323,6 +359,12 @@ int udev_add_device(char *path, char *subsystem)
dbg("name='%s'", dev.name);
retval = create_node(&dev);
+#ifdef USE_DBUS
+ if (retval == 0) {
+ sysbus_send_create(&dev, path);
+ }
+#endif /* USE_DBUS */
+
exit:
if (class_dev)
sysfs_close_class_device(class_dev);
diff --git a/udev-remove.c b/udev-remove.c
index d42ed4be78..307b907c88 100644
--- a/udev-remove.c
+++ b/udev-remove.c
@@ -100,6 +100,42 @@ static int delete_node(struct udevice *dev)
return retval;
}
+#ifdef USE_DBUS
+/** Send out a signal that a device node is deleted
+ *
+ * @param name Name of the device node, e.g. /udev/sda1
+ * @param path Sysfs path of device
+ */
+static void sysbus_send_remove(const char* name, const char *path)
+{
+ char filename[255];
+ DBusMessage* message;
+ DBusMessageIter iter;
+
+ if (sysbus_connection == NULL)
+ return;
+
+ strncpy(filename, udev_root, sizeof(filename));
+ strncat(filename, name, sizeof(filename));
+
+ /* object, interface, member */
+ message = dbus_message_new_signal("/org/kernel/udev/NodeMonitor",
+ "org.kernel.udev.NodeMonitor",
+ "NodeDeleted");
+
+ dbus_message_iter_init(message, &iter);
+ dbus_message_iter_append_string(&iter, filename);
+ dbus_message_iter_append_string(&iter, path);
+
+ if ( !dbus_connection_send(sysbus_connection, message, NULL) )
+ dbg("error sending d-bus signal");
+
+ dbus_message_unref(message);
+
+ dbus_connection_flush(sysbus_connection);
+}
+#endif /* USE_DBUS */
+
/*
* Look up the sysfs path in the database to see if we have named this device
* something different from the kernel name. If we have, us it. If not, use
@@ -122,5 +158,10 @@ int udev_remove_device(char *path, char *subsystem)
dbg("name is '%s'", dev->name);
udevdb_delete_dev(path);
+
+#ifdef USE_DBUS
+ sysbus_send_remove(name, device);
+#endif /* USE_DBUS */
+
return delete_node(dev);
}
diff --git a/udev.c b/udev.c
index bf18a568ea..67b86e5916 100644
--- a/udev.c
+++ b/udev.c
@@ -63,6 +63,60 @@ static inline char *get_seqnum(void)
return seqnum;
}
+#ifdef USE_DBUS
+
+/** Global variable for the connection the to system message bus or #NULL
+ * if we cannot connect or acquire the org.kernel.udev service
+ */
+DBusConnection* sysbus_connection;
+
+/** Disconnect from the system message bus */
+static void sysbus_disconnect()
+{
+ if (sysbus_connection == NULL)
+ return;
+
+ dbus_connection_disconnect(sysbus_connection);
+ sysbus_connection = NULL;
+}
+
+/** Connect to the system message bus */
+static void sysbus_connect()
+{
+ DBusError error;
+
+ /* Connect to a well-known bus instance, the system bus */
+ dbus_error_init(&error);
+ sysbus_connection = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
+ if (sysbus_connection == NULL) {
+ dbg("cannot connect to system message bus, error %s: %s",
+ error.name, error.message);
+ dbus_error_free(&error);
+ return;
+ }
+
+ /* Acquire the org.kernel.udev service such that listeners
+ * know that the message is really from us and not from a
+ * random attacker. See the file udev_sysbus_policy.conf for
+ * details.
+ *
+ * Note that a service can have multiple owners (though there
+ * is a concept of a primary owner for reception of messages)
+ * so no race is introduced if two copies of udev is running
+ * at the same time.
+ */
+ dbus_bus_acquire_service(sysbus_connection, "org.kernel.udev", 0,
+ &error);
+ if (dbus_error_is_set(&error)) {
+ printf("cannot acquire org.kernel.udev service, error %s: %s'",
+ error.name, error.message);
+ sysbus_disconnect();
+ return;
+ }
+}
+
+#endif /* USE_DBUS */
+
int main(int argc, char **argv, char **envp)
{
char *action;
@@ -111,6 +165,11 @@ int main(int argc, char **argv, char **envp)
/* initialize our configuration */
udev_init_config();
+#ifdef USE_DBUS
+ /* connect to the system message bus */
+ sysbus_connect();
+#endif /* USE_DBUS */
+
/* initialize udev database */
retval = udevdb_init(UDEVDB_DEFAULT);
if (retval != 0) {
@@ -133,6 +192,11 @@ int main(int argc, char **argv, char **envp)
}
udevdb_exit();
+#ifdef USE_DBUS
+ /* disconnect from the system message bus */
+ sysbus_disconnect();
+#endif /* USE_DBUS */
+
exit:
return retval;
}
diff --git a/udev.h b/udev.h
index 05f6b3c225..4ea04d5e71 100644
--- a/udev.h
+++ b/udev.h
@@ -93,4 +93,13 @@ extern char udev_config_filename[PATH_MAX+NAME_MAX];
extern char udev_rules_filename[PATH_MAX+NAME_MAX];
extern char default_mode_str[NAME_MAX];
+#ifdef USE_DBUS
+
+#define DBUS_API_SUBJECT_TO_CHANGE
+#include <dbus/dbus.h>
+
+extern DBusConnection* sysbus_connection;
+
+#endif /* USE_DBUS */
+
#endif
diff --git a/udev_sysbus_policy.conf b/udev_sysbus_policy.conf
new file mode 100644
index 0000000000..b2660e65cf
--- /dev/null
+++ b/udev_sysbus_policy.conf
@@ -0,0 +1,23 @@
+<!DOCTYPE busconfig PUBLIC
+ "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+<busconfig>
+
+ <!-- This configuration file specifies the required security policies
+ for udev to work. -->
+
+ <!-- Only root can own the udev service and only root can use the
+ org.kernel.udev.NodeMonitor interface to send signals -->
+ <policy user="root">
+ <allow own="org.kernel.udev"/>
+
+ <allow send_interface="org.kernel.udev.NodeMonitor"/>
+ </policy>
+
+ <!-- Allow anyone to listen to the org.kernel.udev.NodeMonitor interface
+ for messages send from the owner of the org.kernel.udev service -->
+ <policy context="default">
+ <allow receive_interface="org.kernel.udev.NodeMonitor"/>
+ </policy>
+</busconfig>
+