Re: [gpsd-dev] Another release seems called for

[Fulup Le Foll]

Gary

If udev is able to create /dev/ttyUSB0 once, then it has enough permission to create it twice.

When you unplug a device, a good program like gpsd will detect the error and try to reopen the same path (ex: /dev/ttyUSB0) . The "bad" news: If the path does point to an existing file/device with an open syscall Linux will try to create the missing file.

As a result when a program running under "dialout" group try to open /dev/ttyUSB0

• if /dev/ttyUSB0 already exist, then the open call succeeds
  
• if /dev/ttyUSB0 does not exist. You get a permission error because "dialout" is not enough to create the missing file in /dev. Worse if you had enough right to create an empty file in /dev, then 'udev' would move to next available name and would create /dev/ttyUSB1
  

Fulup


Le 24/07/2013 21:56, Gary E. Miller a écrit :

Yo Fulup!

On Wed, 24 Jul 2013 21:37:12 +0200
Fulup Le Foll <address@hidden> wrote:

Naming of device is not a question of timeout but a question of
availability of the path. 

Potentially, but not in my case.  I always have ttyUSB0.  My case is a
permission problem.

RGDS
GARY
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