From: David Taylor <taylor@candd.org>
To: sourcenav@sources.redhat.com
Subject: "multiple" users of a SN project & a bug report
Date: Sun, 15 Jul 2001 18:47:00 -0000 [thread overview]
Message-ID: <200107160147.VAA03032@houston.candd.org> (raw)
From looking at the code and reading some of the archives of this
mailing list, I conclude that it isn't intended for a SN project to be
allowed to be open in two or more processes simultaneously -- which is
a real shame!
For instance, I'd like to be able to
. bring up SN at work
. open a project
. go home (without closing the project)
. login to work from home
. bring up SN from home
. open the project that I have open at work
Having the second one say "it's already open for modification, you
have to open it read-only", might not be too bad. Right now though it
totally refuses to open it.
[At least in SN 5.0; I tried the snapshot dated April 12th, but it
failed to build for me on Red Hat Linux 6.2.]
NOTE: there *IS* a bug in the function sn_is_project_busy
(snavigator/gui/misc.tcl).
Assuming we are on unix, ignore the issue of root opening the project,
and we have a real project, the remaining logic in sn_is_project_busy
reduces to roughly:
. open the project read-only; get list of users; close the project
. if no one is using the project, return ""
. if the project user is on the same machine, then
. if the pid matches our's, return "me"
. if the platform is "unix"
. if the process no longer exists OR is owned by someone else,
then return "" <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< BUG
(you fail to distinguish between failure due to the process
not existing [ESRCH] versus you don't have permission to send
the signal to that process [EPERM].)
. else ...
. if project user matches current user, return "me"
. return "busy"
So,
. if two users, same or different, on different machines try to open
the same project, the second one will fail
. if the same user, tries to open the same project twice on the same
machine, the second attempt will fail
. if different users try to open the same project on the same machine,
the second one will succeed!
[Additionally, there appears to be a race condition present -- two
processes could open the project read-only, check whether there are
current users, see that there are none, and go ahead and re-open
it...]
Take care,
David
--
David Taylor
taylor@candd.org
next reply other threads:[~2001-07-15 18:47 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-15 18:47 David Taylor [this message]
2001-07-16 11:04 ` Mo DeJong
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