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kay.sievers@vrfy.org 33db4b8da0 [PATCH] udev - next round of udev event order daemon
Here is the next round of udevd/udevsend:

udevsend - If the IPC message we send is not catched by a receiver we fork
           the udevd daemon to process this and the following events

udevd    - We reorder the events we receive and execute our current udev for
           every event. If one or more events are missing, we wait
           10 seconds and then go ahead in the queue.
           If the queue is empty and we don't receive any event for the next
           30 seconds, the daemon exits.
           The next incoming event will fork the daemon again.

config   - The path's to the executable are specified in udevd.h
           Now they are pointing to the current directory only.


I don't like daemons hiding secrets (and mem leaks :)) inside,
so I want to try this model. It should be enough logic to get all possible
hotplug events executed in the right order.

If no event, then no daemon! So everybody should be happy :)


Here we see:
  1. the daemon fork,
  2. the udev work,
  3. the 10 sec timeout and the skipped events,
  4. the udev work,
     ...,
  5. and the 30 sec timeout and exit.

EVENTS:
  pim:/home/kay/src/udev.kay# test/udevd_test.sh
  pim:/home/kay/src/udev.kay# SEQNUM=15 ./udevsend block
  pim:/home/kay/src/udev.kay# SEQNUM=16 ./udevsend block
  pim:/home/kay/src/udev.kay# SEQNUM=17 ./udevsend block
  pim:/home/kay/src/udev.kay# SEQNUM=18 ./udevsend block
  pim:/home/kay/src/udev.kay# SEQNUM=20 ./udevsend block
  pim:/home/kay/src/udev.kay# SEQNUM=21 ./udevsend block


LOG:
  Jan 23 15:35:35 pim udev[11795]: message is still in the ipc queue, starting daemon...
  Jan 23 15:35:35 pim udev[11799]: configured rule in '/etc/udev/udev.rules' at line 19 applied, 'sda' becomes '%k-flash'
  Jan 23 15:35:35 pim udev[11799]: creating device node '/udev/sda-flash'
  Jan 23 15:35:35 pim udev[11800]: creating device node '/udev/sdb'
  Jan 23 15:35:35 pim udev[11804]: creating device node '/udev/sdc'
  Jan 23 15:35:35 pim udev[11805]: removing device node '/udev/sda-flash'
  Jan 23 15:35:35 pim udev[11808]: removing device node '/udev/sdb'
  Jan 23 15:35:35 pim udev[11809]: removing device node '/udev/sdc'
  Jan 23 15:35:45 pim udev[11797]: timeout reached, skip events 7 - 7
  Jan 23 15:35:45 pim udev[11811]: creating device node '/udev/sdb'
  Jan 23 15:35:45 pim udev[11812]: creating device node '/udev/sdc'
  Jan 23 15:36:01 pim udev[11797]: timeout reached, skip events 10 - 14
  Jan 23 15:36:01 pim udev[11814]: creating device node '/udev/sdc'
  Jan 23 15:36:04 pim udev[11816]: creating device node '/udev/sdc'
  Jan 23 15:36:12 pim udev[11818]: creating device node '/udev/sdc'
  Jan 23 15:36:16 pim udev[11820]: creating device node '/udev/sdc'
  Jan 23 15:36:38 pim udev[11797]: timeout reached, skip events 19 - 19
  Jan 23 15:36:38 pim udev[11823]: creating device node '/udev/sdc'
  Jan 23 15:36:38 pim udev[11824]: creating device node '/udev/sdc'
  Jan 23 15:37:08 pim udev[11797]: we have nothing to do, so daemon exits...
2005-04-26 21:13:18 -07:00
docs [PATCH] minor grammer fixes for the udev_vs_devfs document 2005-04-26 21:13:14 -07:00
etc [PATCH] set default owner/group in db - update 2005-04-26 21:13:17 -07:00
extras [PATCH] udev - udevinfo with device chain walk 2005-04-26 21:13:18 -07:00
klibc [PATCH] sync klibc with release 0.95 2005-04-26 21:13:08 -07:00
libsysfs [PATCH] libsysfs update for refresh + namedev.c changes 2005-04-26 21:13:16 -07:00
tdb [PATCH] signal fixes due to klibc update. 2005-04-26 21:13:08 -07:00
test [PATCH] udev - next round of udev event order daemon 2005-04-26 21:13:18 -07:00
ChangeLog [PATCH] 014 release 2005-04-26 21:13:17 -07:00
COPYING [PATCH] added initial documentation and gpl license 2005-04-26 21:00:32 -07:00
FAQ [PATCH] update the FAQ with info about bad modprobe events from the devfs scheme... 2005-04-26 21:13:08 -07:00
klibc_fixups.c [PATCH] get rid of functions in klibc_fixups that are now in klibc 2005-04-26 21:13:02 -07:00
klibc_fixups.h [PATCH] udev - exec status fix for klibc 2005-04-26 21:13:14 -07:00
list.h [PATCH] Initial namedev parsing of config files 2005-04-26 21:01:38 -07:00
logging.c [PATCH] add udev logging to info log 2005-04-26 21:13:17 -07:00
logging.h [PATCH] misc code cleanups. 2005-04-26 21:13:17 -07:00
Makefile [PATCH] spilt udev into pieces 2005-04-26 21:13:17 -07:00
namedev_parse.c [PATCH] misc code cleanups. 2005-04-26 21:13:17 -07:00
namedev.c [PATCH] add support for figuring out which device on the sysfs "chain" the rule applies to. 2005-04-26 21:13:17 -07:00
namedev.h [PATCH] add udev logging to info log 2005-04-26 21:13:17 -07:00
README [PATCH] clean up the logging patch a bit to make the option more like the other options. 2005-04-26 21:13:17 -07:00
TODO [PATCH] remove TODO item about BUS value, as it is now done. 2005-04-26 21:13:17 -07:00
udev_config.c [PATCH] set default owner/group in db - update 2005-04-26 21:13:17 -07:00
udev_dbus.c [PATCH] fix formatting of udev_dbus.c to use tabs. Also get it to build properly now. 2005-04-26 21:13:06 -07:00
udev_dbus.h [PATCH] move all of the DBUS logic into one file and remove all of the #ifdef crud from the main code. 2005-04-26 21:13:06 -07:00
udev-add.c [PATCH] set default owner/group in db - update 2005-04-26 21:13:17 -07:00
udev-remove.c [PATCH] add udev logging to info log 2005-04-26 21:13:17 -07:00
udev.8 [PATCH] set default owner/group in db - update 2005-04-26 21:13:17 -07:00
udev.c [PATCH] udev - reverse user query options 2005-04-26 21:13:17 -07:00
udev.h [PATCH] set default owner/group in db - update 2005-04-26 21:13:17 -07:00
udev.spec [PATCH] 014_bk mark 2005-04-26 21:13:17 -07:00
udevd.c [PATCH] udev - next round of udev event order daemon 2005-04-26 21:13:18 -07:00
udevd.h [PATCH] udev - next round of udev event order daemon 2005-04-26 21:13:18 -07:00
udevdb.c [PATCH] udev - reverse user query options 2005-04-26 21:13:17 -07:00
udevdb.h [PATCH] udev - reverse user query options 2005-04-26 21:13:17 -07:00
udevsend.c [PATCH] udev - next round of udev event order daemon 2005-04-26 21:13:18 -07:00

udev - a userspace implementation of devfs

For more information on the design, and structure of this project, see the
files in the docs/ directory.

To use:

- You must be running a 2.6 version of the Linux kernel.

- Your 2.6 kernel must have had CONFIG_HOTPLUG enabled when it was built.

- Make sure sysfs is mounted.  udev will figure out where sysfs is mounted, but
  the traditional place for it is at /sys.  You can mount it by hand by running:
  	mount -t sysfs none /sys

- Make sure you have the latest version of the linux-hotplug scripts.  They are
  available at linux-hotplug.sf.net or from your local kernel.org mirror at:
	kernel.org/pub/linux/utils/kernel/hotplug/
  They are required in order for udev to work properly.

  If for some reason you do not install the hotplug scripts, you must tell the
  kernel to point the hotplug binary at wherever you install udev at.  This can
  be done by:
	echo "/sbin/udev" > /proc/sys/kernel/hotplug

- Build the project:
	make

  Note:
      There are a number of different flags that you can use when building
      udev.  They are as follows:
	prefix
		set this to the default root that you want udev to be
		installed into.  This works just like the 'configure --prefix'
		script does.  Default value is ''.  Only override this if you
		really know what you are doing.
	USE_KLIBC
		if set to 'true', udev is built and linked against the
		included version of klibc.  Default value is 'false'.
	USE_LOG
		if set to 'true', udev will emit messages to the syslog when
		it creates or removes device nodes.  This is helpful to see
		what udev is doing.  This is enabled by default.  Note, if you
		are building udev against klibc it is recommended that you
		disable this option (due to klibc's syslog implementation.)
	USE_DBUS
		if set to 'true', DBUS messages will be sent everytime udev
		creates or removes a device node.  This requires that DBUS
		development headers and libraries be present on your system to
		build properly.  Default value is 'false'.
	DEBUG
		if set to 'true', debugging messages will be sent to the syslog
		as udev is run.  Default value is 'false'.

      So, if you want to build udev using klibc with debugging messages, you
      would do:
	make USE_KLIBC=true DEBUG=true

      Note: If you want to use klibc, you will have to set up the "linux"
            symlink properly.  See the file klibc/klibc/README and pay
	    attention to step "a)" there.

- Install the project:
	make install

  This will put the udev binary in /sbin, create the /udev and /etc/udev
  directories, and place the udev configuration files in /etc/udev.  You
  will probably want to edit the namedev.* files to create custom naming
  rules.  More info on how the config files are set up are contained in
  comments in the files, and is located in the documentation.

- Add and remove devices from the system and marvel as nodes are created
  and removed in /udev/ based on the device types.

- If you later get sick of it, uninstall it:
	make uninstall


Things are still quite rough, but it should work properly.  If nothing
seems to happen, make sure your build worked properly by running the
udev-test.pl script as root in the test/ subdirectory of the udev source
tree.

Development and documentation help is very much appreciated, see the TODO
file for a list of things left to be done.


Any comment/questions/concerns please let me and the other udev developers
know by sending a message to the linux-hotplug-devel mailing list at:
	linux-hotplug-devel@lists.sourceforge.net

greg k-h
greg@kroah.com