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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...
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On Thu, Jan 22, 2004 at 01:27:45AM +0100, Kay Sievers wrote:
> On Wed, Jan 21, 2004 at 02:38:25PM +0100, Kay Sievers wrote:
> > On Thu, Jan 15, 2004 at 01:45:10PM -0800, Greg KH wrote:
> > > On Thu, Jan 15, 2004 at 10:36:25PM +0800, Ling, Xiaofeng wrote:
> > > > Hi, Greg
> > > > I wrote a simple implementation for the two pieces
> > > > of send and receive hotplug event,
> > > > use a message queue and a list for the out of order
> > > > hotplug event. It also has a timeout timer of 3 seconds.
> > > > They are now separate program. the file nseq is the test script.
> > > > Could you have a look to see wether it is feasible?
> > > > If so, I'll continue to merge with udev.
> > >
> > > Yes, very nice start. Please continue on.
> > >
> > > One minor comment, please stick with the kernel coding style when you
> > > are writing new code for udev.
> >
> > I took the code from Xiaofeng, cleaned the whitespace, renamed some bits,
> > tweaked the debugging, added the udev exec and created a patch for the current tree.
> >
> > It seems functional now, by simply executing our current udev (dirty hack).
> > It reorders the incoming events and if one is missing it delays the
> > execution of the following ones up to a maximum of 10 seconds.
> >
> > Test script is included, but you can't mix hotplug sequence numbers and
> > test script numbers, it will result in waiting for the missing numbers :)
>
> Hey, nobody want's to play with me?
> So here I'm chatting with myself :)
>
> This is the next version with signal handling for resetting the expected
> signal number. I changed the behaviour of the timeout to skip all
> missing events at once and to proceed with the next event in the queue.
>
> So it's now possible to use the test script at any time, cause it resets
> the daemon, if real hotplug event coming in later all missing nimbers will
> be skipped after a timeout of 10 seconds and the queued events are applied.
Here is the next updated updated version to apply to the lastet udev.
I've added infrastructure for getting the state of the IPC queue in the
sender and set the program to exec by the daemon. Also the magic key id
is replaced by the usual key generation by path/nr.
It looks promising, I use it on my machine and my 4in1 USB-flash-reader
connect/disconnect emits the events "randomly" but udevd is able to
reorder it and calls our normal udev in the right order.
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