Messages in this thread | | | Date | Fri, 10 Jun 2005 11:36:54 +0200 (CEST) | From | moreau francis <> | Subject | Re: [TTY] exclusive mode question |
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--- Denis Vlasenko <vda@ilport.com.ua> a écrit :
> On Thursday 09 June 2005 18:12, Russell King wrote: > > On Thu, Jun 09, 2005 at 04:22:49PM +0200, moreau francis wrote: > > > --- Frederik Deweerdt <dev.deweerdt@laposte.net> a écrit : > > > > Le 09/06/05 13:41 +0200, moreau francis écrivit: > > > > > > > > > > oh ok...sorry I misunderstood TIOEXCL meaning ;) > > > > > Do you know how I could implement such exclusive mode (the one I > described) > > > > ? > > > > > > > > > This is handled through lock files, google for LCK..ttyS0 > > > > > > > > > > This lock mechanism is a convention but nothing prevent a user > application to > > > issue a "echo foo > /dev/ttyS0" command while "LCK..ttyS0" file exists... > > > > Which is absolutely necessary to work if you think about an application > > like minicom and its file transfer helpers, which may need to re-open > > the serial port. > > > > TTY locking is done via lock files only, and all non-helper applications > > must coordinate their access via the lock files. There is no other > > mechanism. > > I think original reporter is saying that TIOEXCL is nearly useless then. >
Why not using mandatory locks instead of this "weak" user lock mechanism ?
Francis
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