Installation hangs at password prompt

[Jonas Hagen]

1) sudo apt-get install postgresql (on a fresh install of Ubuntu 15.10)
2) Give Password as requested for the configuration of postgresql-common package. (Entered password is visible.)
3) Hit Enter -> process hangs (Ctrl+C or +D do not work either).
4) Only option to exit apt-get is to kill it and delete lock files manually.

Full output of apt-get:
  ...@...:...$ sudo apt-get install postgresql-9.4
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  The following extra packages will be installed:
    postgresql-common postgresql-contrib-9.4
  Suggested packages:
    oidentd ident-server locales-all libdbd-pg-perl
  The following NEW packages will be installed:
    postgresql-9.4 postgresql-common postgresql-contrib-9.4
  0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
  Need to get 0 B/3'433 kB of archives.
  After this operation, 14.8 MB of additional disk space will be used.
  Do you want to continue? [Y/n] y
  Preconfiguring packages ...
  Selecting previously unselected package postgresql-common.
  (Reading database ... 321682 files and directories currently installed.)
  Preparing to unpack .../postgresql-common_169git1_all.deb ...
  Adding 'diversion of /usr/bin/pg_config to /usr/bin/pg_config.libpq-dev by postgresql-common'
  Unpacking postgresql-common (169git1) ...
  Selecting previously unselected package postgresql-9.4.
  Preparing to unpack .../postgresql-9.4_9.4.5-1_amd64.deb ...
  Unpacking postgresql-9.4 (9.4.5-1) ...
  Selecting previously unselected package postgresql-contrib-9.4.
  Preparing to unpack .../postgresql-contrib-9.4_9.4.5-1_amd64.deb ...
  Unpacking postgresql-contrib-9.4 (9.4.5-1) ...
  Processing triggers for man-db (2.7.4-1) ...
  Processing triggers for ureadahead (0.100.0-19) ...
  Processing triggers for systemd (225-1ubuntu9) ...
  Setting up postgresql-common (169git1) ...
  Password:

The configuration via dpkg of postgresql-common also hangs after "Password:" prompt. The password can be entered, but is visible and after hitting enter, nothing happens. Can be aborted by Ctrl+C.

  $ sudo dpkg --configure -a
  Setting up postgresql-common (169git1) ...
  Password: hallo
  ^CPassword change aborted.
  dpkg: error processing package postgresql-common (--configure):
   subprocess installed post-installation script was interrupted
  dpkg: dependency problems prevent configuration of postgresql-9.4:
   postgresql-9.4 depends on postgresql-common (>= 142~); however:
    Package postgresql-common is not configured yet.

System: Ubuntu 15.10
Package: postgresql-common
Version: 169git1

[Christoph Berg (myon)]

I'd think the problem is somewhere in your PAM setup. For some reason "su" is asking for a password even when running as root:

    su -s /bin/sh postgres -c "test -O /var/lib/postgresql &&
            test -G /var/lib/postgresql" || \
        chown postgres:postgres /var/lib/postgresql

To be sure where it is really asking, add "set -x" to the beginning of /var/lib/dpkg/info/postgresql-common.postinst and do the dpkg --configure -a again.

[Jonas Hagen (jonas-hagen3)]

Yes, this was it. Thanks a lot!

[pravin.chaudhary (pravin-chaudhary-6)]

I am facing this on ubuntu 18.04.

I added "set -x" to the beginning of /var/lib/dpkg/info/postgresql-common.postinst and did the dpkg --configure -a again, as suggested by Christoph. The output is given below, I can't make out anything from that:

$ sudo dpkg --configure -a
Setting up postgresql-common (190) ...
+ set -e
+ [ postgresql-common ]
+ . /usr/share/debconf/confmodule
+ [ ! ]
+ PERL_DL_NONLAZY=1
+ export PERL_DL_NONLAZY
+ [ ]
+ exec /usr/share/debconf/frontend /var/lib/dpkg/info/postgresql-common.postinst configure
+ set -e
+ [ postgresql-common ]
+ . /usr/share/debconf/confmodule
+ [ ! 1 ]
+ [ -z ]
+ exec
+ [ ]
+ exec
+ DEBCONF_REDIR=1
+ export DEBCONF_REDIR
+ SSL_ROOT=/etc/postgresql-common/root.crt
+ [ configure = configure ]
+ [ postgresql-common ]
+ quiet=--quiet
+ getent passwd postgres
+ getent group postgres
+ + id -Gn postgres
grep -qw postgres
+ id -u postgres
+ [ 126 -eq 0 ]
+ id -g postgres
+ [ 129 -eq 0 ]
+ mkdir -p /var/lib/postgresql
+ su -s /bin/sh postgres -c test -O /var/lib/postgresql &&
            test -G /var/lib/postgresql

[lai (whlai)]

I have the same issue in a new install of 18.04 as @pravin.chaudhary

How do we fix this?

[Steve Langasek (vorlon)]

As stated previously, if su is blocking prompting for a password when run as root, this is a bug in your pam /config/. It is not a bug in the pam package.

On a default system there is no problem installing postgresql-common.

[Michel Verbist (michel-verbist)]

I also had a smb mount configured via pam_mount.
I solved this by excluding some users (root and postgres) from the mounting of the volume, like this.

<volume fstype="cifs" server="xxxxx" path="%(USER)" mountpoint="/home/%(USER)/xxxx" options="vers=2.0,credentials=/home/%(USER)/.smbcredentials">
  <and>
    <not>
      <user>root</user>
    </not>
    <not>
      <user>postgres</user>
    </not>
  </and>
</volume>