rocm-systems/projects/rdc/src/DEBIAN_postinst.in

#!/bin/bash

do_update_alternatives(){
    # skip update if program doesn't exist
    command -v update-alternatives >/dev/null || return 0
    local binaries altscore now
    now=$(date -u +%s)          # Number of seconds since 1 Jan 1970

    # The reason for this approach rather than using the build number
    # is to allow for jobs from different builds. In one build job the
    # job number might be at 1200, whilst in a release job the number
    # may be only 1. This approach assums that if you install a build
    # with a different semantic version then the highest is the
    # desired one, but if you install two with the same semver then
    # the newest is the desired version.

    # Build up a score. It needs to fit in 32 bits
    altscore=$((@VERSION_MAJOR@ - 3))
    altscore=$((altscore * 14 + @VERSION_MINOR@)) # Allow up to 14 minor
    altscore=$((altscore * 14 + @VERSION_PATCH@)) # Allow up to 14 patch

    # So far if the version is less than 9 we have a number (altscore)
    # that is less than 1175.  2**31/1175 is about 1.8 million. So
    # multiply altscore by 1,000,000 and add in a factor of how many
    # minutes have passed from an arbitary point in time (1,600,000,000
    # seconds after 1 Jan 1970 or Sep 13 12:26:40 2020) on the
    # basis that no one is going to be installing a new version more
    # often than every minute. This does get things wrong if a million
    # minutes pass and you are downgrading, but the chances of someone
    # waiting almost 2 years between installing a version and the
    # previous patch level is small.

    altscore=$((altscore*1000000+(now-1600000000)/60))

    binaries=(
        rdcd
        rdci
    )

    for i in "${binaries[@]}"
    do
        # No obvious recover strategy if things fail
        # No manual or other slave pages to install
        if [ -e @CPACK_PACKAGING_INSTALL_PREFIX@/@CMAKE_INSTALL_BINDIR@/"$i" ]
        then
            update-alternatives --install /usr/bin/"$i" "$i" \
                                @CPACK_PACKAGING_INSTALL_PREFIX@/@CMAKE_INSTALL_BINDIR@/"$i" "$altscore"
        else
            echo "@CPACK_PACKAGING_INSTALL_PREFIX@/@CMAKE_INSTALL_BINDIR@/$i not found, but that is OK" >&2
        fi
    done
    true
}

# This will return 0 if an id is created and non-zero if
# it already exists
# https://www.debian.org/doc/debian-policy/ch-opersys.html#users-and-groups
do_create_rdc_user() {
    # create rdc group
    if ! getent group rdc > /dev/null 2>&1 ; then
        addgroup --system rdc
    fi

    # create rdc user
    if ! getent passwd rdc > /dev/null 2>&1 ; then
        adduser \
            --system \
            --quiet \
            --home /nonexistent \
            --no-create-home \
            --disabled-password \
            --ingroup rdc \
            rdc
    fi

    # only add render if it exists
    if getent group render > /dev/null 2>&1 ; then
        usermod -a -G render rdc
    fi

    # add video always
    usermod -a -G video rdc

    # Make sure this doesn't return non-zero if an id already exists
    return 0
}

create_rdc_service() {
    #Symlink RDC Service
    if [ -d /run/systemd/system ]; then
        ln -s -f -r @CPACK_PACKAGING_INSTALL_PREFIX@/@CMAKE_INSTALL_LIBEXECDIR@/rdc/rdc.service /lib/systemd/system/rdc.service
    fi
}

reload_systemd() {
    if [ -d /run/systemd/system ]; then
        systemctl daemon-reload
    fi
    return 0
}

case "$1" in
   configure)
       do_update_alternatives
       do_create_rdc_user
       create_rdc_service
       reload_systemd
       exit 0
   ;;
   abort-upgrade|abort-remove|abort-deconfigure)
       echo "$1"
   ;;
   *)
       exit 0
   ;;
esac