[Installer] One-step install command leads to minimal whiptail sizes

[MichaIng]

In raising this issue, I confirm the following:

• I have read and understood the contributors guide.
• The issue I am reporting can be replicated.
• The issue I am reporting isn't a duplicate (see FAQs, closed issues, and open issues).

How familiar are you with the the source code relevant to this issue?:

10

---

Expected behaviour:

• The installer should estimate terminal dimensions correctly to show whiptail dialogs in intended size.

Actual behaviour:

• When calling the installer with the official one-step command curl -sSL https://install.pi-hole.net | bash, the whiptail dialogs have always minimal size.

Steps to reproduce:

• Check actual terminal dimensions: stty size
  • Increase screen/terminal dimensions if it is equal or below 40x140 to assure that the effect is visible.
• Run installer: curl -sSL https://install.pi-hole.net | bash
• Verify that first whiptail dialog has neither half height nor half width of terminal dimensions, as intended, instead it is 20x70, the forced minimum:
  

Troubleshooting undertaken, and/or other relevant information:

• https://github.com/pi-hole/pi-hole/blob/development/automated%20install/basic-install.sh#L87-L104
• The installer checks for an attached standard input [ -t 0 ], before checking terminal dimensions. If bash is called within a pipe, it does not have one:

2020-05-10 14:55:12 root@VM-Buster:~# echo '[ -t 0 ] && echo STDIN available || echo STDIN not available' | bash
STDIN not available
2020-05-10 14:56:19 root@VM-Buster:~# bash <<< '[ -t 0 ] && echo STDIN available || echo STDIN not available'
STDIN not available
2020-05-10 14:56:46 root@VM-Buster:~# bash -c '[ -t 0 ] && echo STDIN available || echo STDIN not available'
STDIN available

• This makes sense of course since in the first two cases STDIN is blocked for bash code input.
• Because of this the installer defaults to 24 80 which leads to minimum 20x70 whiptail dimensions.
• It totally makes sense to check for STDIN since this is indeed required for stty to work:

2020-05-10 14:56:55 root@VM-Buster:~# echo 'stty size' | bash
stty: 'standard input': Inappropriate ioctl for device
2020-05-10 14:59:05 root@VM-Buster:~# bash <<< 'stty size'
stty: 'standard input': Inappropriate ioctl for device
2020-05-10 14:59:18 root@VM-Buster:~# bash -c 'stty size'
71 237

• tput is an alternative to get terminal dimensions, which does not rely on SDTIN, hence can be called from within a pipe:

2020-05-10 14:59:26 root@VM-Buster:~# echo 'tput lines; tput cols' | bash
71
237
2020-05-10 15:01:08 root@VM-Buster:~# bash <<< 'tput lines; tput cols'
71
237
2020-05-10 15:01:16 root@VM-Buster:~# bash -c 'tput lines; tput cols'
71
237

• However at least on Debian/Ubuntu it is part of the ncurses-bin package. It has the "required" tag, hence can be expected in most cases, but it is not marked as "essential" (stronger than "required") like coreutils, which contains the stty command.
• Moreover tput has another issue, at least on Debian until including Stretch. Instead of STDIN it requires either STDOUT or STDERR to be attached to the terminal. If both are redirected, e.g. someone pipes installer output to tee to create a log file, it does not work:

2020-05-10 15:08:37 root@VM-Stretch:~# tput lines
71
2020-05-10 15:08:47 root@VM-Stretch:~# tput lines 2>1 | tee
24
2020-05-10 15:08:52 root@VM-Stretch:~# tput lines | tee
71
2020-05-10 15:08:56 root@VM-Stretch:~# tput lines 2>/dev/null
71
2020-05-10 15:09:08 root@VM-Stretch:~# tput lines 2>1 > log
2020-05-10 15:09:25 root@VM-Stretch:~# cat log
24
2020-05-10 15:09:28 root@VM-Stretch:~# tput lines > log
2020-05-10 15:09:31 root@VM-Stretch:~# cat log
71

• Since Debian Buster this is not an issue anymore.

Suggested solution:

Since stty simply cannot work without free STDIN and there might be other commands affected as well, and since tput has another limitation on older distro versions + adds a package dependency, I suggest to change the one-line install command:

bash -c "$(curl -sSfL https://install.pi-hole.net)"

• bash -c allows to preserve all file descriptors (STDIN, STDOUT, STDERR) for best compatibility with commands that interact with the terminal in any way.
• The additional curl -f option leads to 40X responses to be treated as errors, so that curl exits, instead of forwarding a possible error page html code to be executed by bash: https://manpages.debian.org/buster/curl/curl.1.en.html#OPTIONS

[dschaper]

curl -sSL https://install.pi-hole.net | bash hasn't ever had a problem with whiptail for me. This is the first issue mentioning it, so "whiptail dialogs have always minimal size" seems to be a bit of a misstatement?

[dschaper]

Is that a terminal emulator screencap? Is it really 150x300? Or do you just have it set to really small fonts?

[MichaIng]

@dschaper
In my case it's via PuTTY, made fullscreen on full HD display, see stty size output above: 71 lines 237 chars
Ah, did you mix up pixels with lines/chars? E.g. 1920x1200 pixels (my screen) means with usual font size (16x8) 75 lines height and 240 characters width, minus PuTTY window borders this fits the 71x237 available characters I got.

Please rerun the troubleshooting commands I've posted above, so you can try to replicate the underlying issues on your setup. I don't believe that this is different on different distros but at least I never tested it on Fedora or CentOS.

[dschaper]

I have 4k display, my terminal emulator is set to 140x50, this seems more of a self-inflicted issue.

The information in the dialog boxes won't change, you'll just have huge whiptail boxes with a single sentence and acres of whitespace. I'd rather have small boxes.

For me this isn't an issue.

[dschaper]

And really, you don't need to @ me, I read everything.

[PromoFaux]

I mean, I rarely fullscreen my terminal on my 3840x1080 monitor, but just for fun:

Current one liner command:

With the proposed:

Personally I prefer the former. I don't need the whiptail to expand to fit the screen, the information within stays at the same size, and looks better in the smaller window.

Besides which, I think the proposed command is arguably more prone to user error (obviously not if they copy paste), but there is more to go wrong when typing it out.

[MichaIng]

If you mean the minimum dimensions are enough and beautiful for all dialog boxes, why the whole effort of estimating terminal dimensions is done? Basically it is true, besides in some cases (upstream DNS selection) one needs to scroll through the selection menu while with bigger dialog it is shown fully expended.

But there is one dialog for which the minimum is too small, when you reset/refresh the install with the one-liner:

Running pihole -r btw leads to this bigger whiptail dialogs of course. So if this is not wanted, I suggest to remove the terminal size estimation and instead set dimensions for all whiptail dialogues individually so that everything fits inside nicely.

[dschaper]

If your argument is "Why even do it?" my response will be to remove it completely instead of changing it for your edge case.

[dschaper]

We just need to make the Reconfigure response shorter or break it to two lines.

[MichaIng]

@dschaper
This is not "my edge case". You can simply run the troubleshooting commands I did above and verify yourself that the current estimation is simply broken with the one-liner. However yeah I agree that it is probably easier to remove this, indeed very large whiptails look ugly as well. It should be just assured that every whiptail fits into a reasonable minimum screen, e.g. the 20x70 that is used as minimum already.

[dschaper]

@MichaIng

Great, will look it over.

[dschaper]

@MichaIng

It's whiptail, not a responsive webpage.

[dschaper]

@MichaIng

I prefer the smaller dialog box.

[MichaIng]

I only know this from Debian for sure, but actually whiptail allows to auto-adjust the dimensions based on content, by using 0 0 0 for the dimensions, e.g.:

whiptail --menu 'short' 0 0 0 1 one 2 two

whiptail --menu 'looooooooooooooooooooooooooooooooooooooooooooooooooonger\nand\nwith\nmultiple\nlines' 0 0 0 1 one 2 two 3 three 4 four 5 five

First the menu, then the text is made scrollable automatically when content exceeds terminal dimensions:

Only a few very long lines on large terminal make it again ugly, so line breaks need to be added manually then:

This is undocumented, hence not sure if supported on all distros/newt/whiptail versions, but easier then verifying whiptail size on every content change?

[yubiuser]

@MichaIng

Is this issue fixed by your PR #4229

[MichaIng]

Ah yes, it is 👍.