I'm current trying to install an app into /Applications using SUPlainInstallerInternals (cut out from the Sparkle framework) see here
Even when logged in on an admin account, I'm still being prompted for a username/password to install the .app into /Applications because this line checks both /Applications and / for write permissions, and of course my admin account doesn't have write permission to /Applications (only root does)
So my question is: why check this parent parent folder, it seems irrelevant to me.
Secondly: this means I must authenticate as root to install, and the files when moved subsequently get the user/group of root/admin. Here's the Info.plist file once it's moved to /Applications/Quicksilver.app/Contents/Info.plist
-rw------- 1 root admin 3033 Mar 29 18:30 Info.plist
This means the app can't be launched as there's no read access.
I can also confirm that when trying to copy the app over to /Applications from a guest account, the same permissions are set on the files in /Applications/Quicksilver.app and hence I cannot open the app on a guest account either.