[Bug 584936] Re: gpsd cannot open /dev/ttyUSB0

[Ubuntu Foundations Team Bug Bot]

The attachment "gpsd_default_group.patch" seems to be a patch.  If it
isn't, please remove the "patch" flag from the attachment, remove the
"patch" tag, and if you are a member of the ~ubuntu-reviewers,
unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by
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** Tags added: patch

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https://bugs.launchpad.net/bugs/584936

Title:
  gpsd cannot open /dev/ttyUSB0

Status in “gpsd” package in Ubuntu:
  Confirmed

Bug description:
  Binary package hint: gpsd

  from the man page:

  > gpsd must start up as root in order to open the NTPD shared-memory segment, open its logfile, and create its local control
  > socket. Before doing any processing of GPS data, it tries to drop root privileges by setting its UID to "nobody" (or another userid
  > as set by configure) and its group ID to the group of the initial GPS passed on the command line — or, if that device doesn't
  > exist, to the group of /dev/ttyS0.

  > The assumption behind gpsd's particular behavior is that all the tty devices to which a GPS might be connected are owned by
  > the same non-root group and allow group read/write, though the group may vary because of distribution-specific or local
  > administrative practice. If this assumption is false, gpsd may not be able to open GPS devices in order to read them (such
  > failures will be logged)."

  since I have no /dev/ttyS0 and gpsd is configured for start up without
  any devices / adding devices later via hotplug / control socket it
  switches it's user-/group-id to nobody(65535) / root(0) and can
  therefore not open /dev/ttyUSB0 which is later created with group id
  dialout by udev.

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