[GRASS-user] Fwd: GRASS on SSHFS

Glynn Clements glynn at gclements.plus.com
Thu Dec 13 03:48:56 PST 2012

Markus Metz wrote:

> > 1. To prevent multiple GRASS sessions from using the same mapset
> > directory. A lock file prevented a user from having more than one
> > session, and the ownership check prevented anyone other than the
> > directory's owner from using a directory as the current mapset.

> > Point #1 is no longer relevant, but point #2 is, at least on
> > multi-user systems.
> Point #1 still applies in some environments, e.g. centralized GRASS
> database, users can log in with the same user name and uid from
> different machines. We are using such an environment.

Point #1 is no longer relevant, as GRASS now puts the .gislock file in
the mapset directory. It used to put it in the user's home directory. 
This prevented a single user from starting multiple sessions, but the
ownership check was required to prevent other users from starting
sessions in the same mapset directory.

> > On Windows, the checks are bypassed because Windows' stat() function
> > doesn't report the owner and Windows doesn't have getuid().
> There is a new function G_owner(), r49747, which reports the owner and
> works also on Windows. We could now activate lock files and ownership
> tests for Windows.

On Unix, ownership checks should use the UID, not the username.

On Windows, the permission mechanism is sufficiently complicated that
I'd be inclined to disable ownership checks by default.

Glynn Clements <glynn at gclements.plus.com>

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