set_gtm_env appends duplicate entries to $PATH

[Jon Tai]

We currently just blindly append the instance's GT.M directory to the $PATH. This is sloppy at best, but because we're appending to the end, it could be wrong in some cases, e.g., when another instance's GT.M directory is already in the $PATH.

We should strip out existing GT.M directories from the $PATH before appending ours.

[Jon Tai (jontai)]

Here's a specific failure scenario for this bug. Let's say you have two OpenVista instances, A and B. A was created with GT.M V5.3-004A, but B was created with GT.M V.4-000. Both have running processes (TaskMan, RPC broker etc.). During the nightly backup, the /etc/cron.daily/openvista calls set_gtm_env and appends the /opt/openvista/A/gtm to the $PATH, then runs ovbackup to back up A. ovbackup appends /opt/openvista/A/gtm to the $PATH again before calling mupip. Since the two entries are the same, it's not a problem (although it's redundant).

Once A is backed up, /etc/cron.daily/openvista calls ovbackup to back up B. ovbackup appends /opt/openvista/B/gtm to the $PATH before calling mupip, but /opt/openvista/A/gtm comes first in the $PATH, so the mupip from GT.M V5.3-004A is used instead of the mupip from GT.M V5.4-000. The backup fails with a %GTM-E-VERMISMATCH error.