Non-default wallpapers are not readable by Unity-Greeter

My gut feeling is that we should not do this. If you protect your files to not be world-readable, or they are on an ecryptfs container, the greeter should not subvert this and copy them to other places.

Well Martin the issue has been discussed a bit in another bug (looking for the number), even if the file is publicly available that doesn't work because gnome-desktop store your background in .cache which has permissions set to 700 by default so even if the image can be read the actual copy used and stored can't

I this case, why doesn't the greeter fall back to reading the actual file instead of the cache?

Well I guess that's what this bug is about ;-) The current implementation just store in accountsservice the url of the file used by the desktop which is in .cache, the fact that the dir is 700 and such not accessible to the greeter was probably overlooked

If I may, there is a fix to this, but it requres the use of gsettings or the Dconf editor.

If there was a way to parse the wallpaper file name as it is being set and send it to the gsettings command, this would be easily fixed.

The command would look like:
gsettings set org.gnome.desktop.background picture-urt 'file:://<full_path_name>'

Moustafa Chamli [2012-02-16 18:21 -0000]:
> If I may, there is a fix to this, but it requres the use of gsettings or
> the Dconf editor.

That's not the problem, and it wouldn't help. We know the name of the
wallpaper, but if the file is not accessible to the lightdm user it
still couldn't display it. Also, for e. g. an encrypted home directory
you can't read the gsettings either.

Martin
--
Martin Pitt | http://www.piware.de
Ubuntu Developer (www.ubuntu.com) | Debian Developer (www.debian.org)

Couldn't the Appearance setting tool have a script which would change the dconf value? I'm mainly saying it would be a workaround, having set the wallpaper myself from within the session.

That said, I haven't tried it for an encrypted Home directory, so I can't confirm it would fix it.

I don't really know what happen behind the hood, but when i use wallpaper with the same resolution as your monitor, the wallpaper change does work.

Any idea about this?

The issue is coming quite often, we should try to figure if we want to "fix" things to display backgrounds from "public" dirs like the xdg Image user dir or not...

My monitor is 1280*1024
The image I want is 700*467 and is jpg.

If I am trying to change my wallpaper through system settings, and then disconnect, then my greeter on login is the pink one.

-Now go to your photo through nautilus
-open it with image viewer
- right click the same photo and choose "set as wallpaper" in the menu

disconnect and Tadaa !!! lightdm greeter is my background !!!!

Any clue ?

it didn't work with a picture that was 4000*3000...

Is anyone using the encyrpted home directory option, would the chosen background need to be copied out of the home folder say /usr/share/backgrounds otherwise unity-greeter wouldnt be able to read the image even in .cache

the gnome-control-center update should fix the case where settings public local files was not working, it will probably not solve the non available files in the user dir cases

Most definitely, since this is a behaviour that annoys people and has an apparently unpredictable pattern (in reality, it's just that the partition is encrypted, but nothing prompts the user), this must be fixed.

So either you say "look, your backdrop is not going to be shown in the greeter, which will show the standard one" or you just take the plunge and copy the backdrop to /usr/share/something and let the damn thing bring it up.

Lol i agree ;)

Agree with Carlo, lets just copy the image to '/usr/share/backgrounds-current' for example. We live in 2012, hard disk space is not that rare.

Thanks but it's not very useful telling others what they "must" fix, there is lot to do, if you want to help patches are welcome

Copying would mean you would made any background public where users might not want to share their background

Which is a moot point, since the original background file likely resides somewhere in ~/Pictures, which is world-readable by default.

So... I just installed Precise and I saw this cool new feature of showing up the wallpaper in the login screen... I thought it was great until I used a custom wallpaper.... so I have this problem too. I have encrypted my home directory but I still want to show my non-default wallpaper (located in home/Images directory) in the login screen.

Please fix this. Perhaps an option in the background options window will resolve the "privacy" issues you guys have discussed here. The option would be something like "Show the wallpaper in the login screen" (check for yes or no). So if that option is set to yes, I guess the wallpaper file should then be copied to '/usr/share/backgrounds' (for example) so the login screen has always access to the file and show the wallpaper.

As for the comment of "Sebastien Bacher", which I assume he would also tell he same thing, I must say that I'm not a programmer but I'm sure Ubuntu programmers welcome suggestions, and that they won't take them like we (non-programmers) are telling them what to do without giving any "real help". Our help are the suggestions and bug reports.

Thank you for your time.

A workaround is to copy the desired wallpaper into /usr/share/backgrounds and rename it using one of the filenames of the default files found there:
$ sudo mv /usr/share/backgrounds/Delicate_Petals_by_lefthandgergo.jpg /usr/share/backgrounds/Delicate_Petals_by_lefthandgergo.bkp
$ sudo cp ~/Pictures/a-blue2.jpg /usr/share/backgrounds/Delicate_Petals_by_lefthandgergo.jpg
$ sudo chmod 644 /usr/share/backgrounds/Delicate_Petals_by_lefthandgergo.jpg

Now, opening System Settings -> Apperance should display your photo as Delicate_Petals_by_lefthandgergo.jpg

By the way, default dynamic wallpaper (e.g. the blue stripes, changing with time) are not displayed either.

Maybe the first image (or the last used) should be displayed.

I realized, that this bug still exist in Quantal.
It has to be fixed for now...

Confirmed in Ubuntu 13.04 Raring Ringtail

Making my "images" folder readable by "other group" makes unity-greeter change it's background

Still present in Saucy (and probably Trusty too?).

Yes, still present in Trusty :(

Is there anyone working on this bug?

Personally, I haven't been affected by this bug anymore.

(Also, I stopped having my HOME encrypted, and now I use full disk encryption, which is a better solution anyhow)

Now, when you right click on an image and "Set as wallpaper", it'll get copied to ~/Pictures/Wallpapers this folder is world readable, so if the issue was with the folder, it's now solved. The file itself still retains its permissions, but I think this is on purpose.

If a custom wallpaper is added with the + button inside the control panel, the picture is not copied, so you'd need to workaround that manually.

I think all of this might still be an issue if the HOME is encrypted.

The Precise Pangolin has reached end of life, so this bug will not be fixed for that release