How does Trash Can works? Where can i find official specification / documentation / reference about it?

Posted by MestreLion on Ask Ubuntu See other posts from Ask Ubuntu or by MestreLion
Published on 2011-02-19T23:42:27Z Indexed on 2011/02/20 7:33 UTC
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When trying to manage trash can from mounted NTFS volumes, I ended up reading FreeDesktop.org's reference on it.

Poking around and doing some tests, I realized Ubuntu/Gnome does not follow the specs 100%. Here's why:

  • For non-/ partitions, it always use <driveroot>/.Trash-<uid>, It never used <driveroot>/.Trash/<uid>, even when i created it in advance. While this works, its annoying: if i have 15 users, i end up with 15 /.Trash-xxx folders in my drive, while the other approach would still give a single folder (with 15 sub-folders). That "pollution" in my drives is very unpleasant. And specs say "If an $topdir/.Trash directory is absent, an $topdir/.Trash-$uid directory is to be used". Well, it IS present, so why it never uses it?

  • root trash does not work, at least not out of the box. Open nautilus as root and click on trash, it gives error. Try to delete any file, it says "it cant move to trash". Ok, i know this can be fixed by creating /root/.local/share. But specs says "A “home trash” directory SHOULD be automatically created for any new user. If this directory is needed for a trashing operation but does not exist, the implementation SHOULD automatically create it, without any warnings or delays.". Why error then? Bug?

  • Why do i must change /etc/fstab entries for mounted volumes, adding options like uid and guid, if the volumes are already mounted as RW for everyone?

These are just some examples of deviation from standard. So, the question is:

"If Ubuntu does not adhere 100% to the spec, HOW exactly does the trash work? WHERE can i find technical reference about Ubuntu's implementation of the trash?"

By the way: if Ubuntu does happen to follow specs, please tell me what am i doing wrong, specially regarding the /.Trash-<uid> vs /.Trash/<uid> issue.

Thanks!

EDIT:

Some more info:

  • If a given fs has no support for sticky bit (VFAT, NTFS), it probably dont have for permitions either (at least VFAT surely doesnt). So what prevents one user for purging / restoring other users ./Trash-xxx ? If one can read/write his own Trash, he can also do the same for the whole drive, including other's trashes, isnt it? Or does Gnome has any "extra" protection on ./Trash-xxx folders on VFAT/NTFS fs?

  • If Linux can "emulate" file permitions on NTFS mounting by editing /fstab uid and gid options, can it also "emulate" the sticky bit? I would really want to use /.Trash/xxx format...

  • For the root issue: for the / partition, i can trash as root, and it goes to /root/.local/shate/Trash. But if i click on Nautilus "Trash" (as root), i get an error. Dont you? So files are correctly trashed, but i cant access it. All i can do is manually "purge" them (by deleting files on /root/.local/shate/Trash), but restoring would be very tricky (opening info files and manually moving, etc)

  • For non-/ partitions (or at least for VFAT/NTFS), I can not even trash as root: it does not create a ./Trash-0 folder, it simply says "Cannot trash, want to permantly delete?" Why?

  • About fstab: i use it for a permanent mount for my NTFS partitions. I have several, and if not "pre-mounted" they really cluttter desktop and/or Nautilus. Id rather have it pre mounted, integrated in my fs, in mounts like /data , /windows/xp , /windows/vista , and so on, and leave /media and its "mount/unmount" flexibility just for truly removable drives

Si, if Ubuntu/Gnome truly follow the spec, is there any way to fix the root issues and to "emulate" the sticky bit for (at least) my fstab'ed NTFS fixed partitions?

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