Background
I was attempting to upgrade my libc6 version in a "not" nice way. It all started with me trying to update my MariaDB from 10.1 to 10.2. I somehow then managed to find out that libc6=1.24 that was installed, was not good enough, and that it required libc6=1.27. I managed to break my installation, when I used dpkg -i on a downloaded package here: http://archive.ubuntu.com/ubuntu/pool/main/g/glibc/ (specifically libc6_2.27-3ubuntu1_amd64.deb). I allowed it to automatically deconfigure my other packages, and this is when I know I ruined it.
My system is running
root@redfox:~# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 9.13 (stretch)
Release: 9.13
Codename: stretch
Current issue
Now, whenever i try to use dpkg, or try to run apt-get upgrade I run in to missing programs and also having missing / broken dependencies. Here is output:
root@redfox:~# sudo apt-get install -f
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... Done
The following packages were automatically installed and are no longer required:
cups-core-drivers hplip-data libart-2.0-2 libcupscgi1 libgutenprint2 libsane-hpaio python3-pexpect python3-pil python3-ptyprocess
python3-renderpm python3-reportlab python3-reportlab-accel
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
hplip libgcc1:i386 printer-driver-gutenprint printer-driver-hpcups printer-driver-postscript-hp
0 upgraded, 0 newly installed, 5 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 4370 kB disk space will be freed.
Do you want to continue? [Y/n] n
Abort.
root@redfox:~# dpkg --configure -a
dpkg: warning: 'ldconfig' not found in PATH or not executable
dpkg: error: 1 expected program not found in PATH or not executable
Note: root's PATH should usually contain /usr/local/sbin, /usr/sbin and /sbin
What have I done to try to fix it?
I have attempted to downgrade to libc6 version 1.24 again, but I am not sure if that worked out too well. I have also tried to clear package cache, autoclean etc, but I am unfortunately quite stuck on where to go next. I have tried to research what I can do, but it is hard to understand as I feel this is a very specific problem to my state, unfortunately.
Edit #1
I have tried to cp /bin/true /sbin/ldconfig, as I found that /sbin/ldconfig was missing. However, it seems like the system is even more damaged than first assumed. Here is output when i try to install packages suggested in the answer of Stephen Kitt below:
sudo dpkg -i libc-bin_2.24-11+deb9u4_amd64.deb locales_2.24-11+deb9u4_all.deb
Selecting previously unselected package libc-bin.
(Reading database ... 202484 files and directories currently installed.)
Preparing to unpack libc-bin_2.24-11+deb9u4_amd64.deb ...
Unpacking libc-bin (2.24-11+deb9u4) ...
Selecting previously unselected package locales.
Preparing to unpack locales_2.24-11+deb9u4_all.deb ...
Unpacking locales (2.24-11+deb9u4) ...
dpkg: dependency problems prevent configuration of libc-bin:
libc-bin depends on libc6 (>> 2.24); however:
Package libc6:amd64 is not configured yet.
libc-bin depends on libc6 (<< 2.25); however:
Version of libc6:amd64 on system is 2.27-3ubuntu1.
dpkg: error processing package libc-bin (--install):
dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of locales:
locales depends on libc-bin (>> 2.24); however:
Package libc-bin is not configured yet.
libc6:amd64 (2.27-3ubuntu1) breaks locales (<< 2.27) and is unpacked but not configured.
Version of locales to be configured is 2.24-11+deb9u4.
dpkg: error processing package locales (--install):
dependency problems - leaving unconfigured
Errors were encountered while processing:
libc-bin
locales
