distro-os.sh

#
# File: distro-os.sh
# Title: Determine OS distro and their directory specifications
# Description:
#   prefix [/usr]
#   sysconfdir [/etc]
#   exec_prefix [/usr]
#   libdir [/var/lib]
#   DEFAULT_PKG_NAME=
#   DEFAULT_ETC_CONF_DIRNAME=
#
# POSIX unix
#
# Privilege required: none
# OS: all
# Kernel: Linux
#
# Files impacted:
#  read   - /etc/os-release
#  create - none
#  modify - none
#  delete - none
#
# Note:
#   This is a bizarre use of Microsoft DotNet for GUI-less hosts.
#   Made NOT an executable due to lack of security review
#
# Environment Variables (read):
#   BUILDROOT - set to '/' to actually install directly into your filesystem
#
# Environment Variables (created):
#   ID (os-release)
#   prefix="${prefix:-${DISTRO_PREFIX}}"
#   sysconfdir="${sysconfdir:-${DISTRO_SYSCONFDIR}}"
#   exec_prefix="${exec_prefix:-${prefix:-$DISTRO_EXEC_PREFIX}}"
#   libdir="${libdir:-$DEFAULT_LIB_DIRSPEC}"
#   libexecdir="${libexecdir:-"${exec_prefix}/libexec"}"
#   localstatedir="${localstatedir:-"$DISTRO_LOCALSTATEDIR"}"
#   datarootdir="${datarootdir:-"${prefix}/share"}"
#   sharedstatedir="${sharedstatedir:-"${prefix}/com"}"
#   bindir="${bindir:-"${exec_prefix}/bin"}"
#   sbindir="${sbindir:-"${exec_prefix}/sbin"}"
#   rundir="${rundir:-"${localstatedir}/run"}"
#
# Prerequisites (package name):
#   /etc/os-release (base-files)
#
# References:
#   none
#

VAR_DIRSPEC="/var"
# shellcheck disable=SC2034
USR_DIRSPEC="/usr"
# shellcheck disable=SC2034
ETC_DIRSPEC="/etc"
# shellcheck disable=SC2034
VAR_CACHE_DIRSPEC="${VAR_DIRSPEC}/cache"
# shellcheck disable=SC2034
VAR_LIB_DIRSPEC="${VAR_DIRSPEC}/lib"
# shellcheck disable=SC2034
USR_LIB_DIRSPEC="${USR_DIRSPEC}/lib"

source /etc/os-release

# Probably should have 'source distro-package-specific' scripting go here
# Needs to deal with 'DEFAULT_ETC_CONF_DIRNAME' there.

# libdir and $HOME are two separate grouping (that Fedora, et. al. merged)
case $ID in
debian | devuan)
  DISTRO_PREFIX="/usr"
  DISTRO_EXEC_PREFIX="/usr"
  DISTRO_LOCALSTATEDIR=""
  DISTRO_SYSCONFDIR="/etc"
  DEFAULT_LIB_DIRSPEC="/var/lib"
  export WHEEL_GROUP="sudo"
  ;;
centos | fedora | redhat)
  DISTRO_PREFIX="/usr"
  DISTRO_EXEC_PREFIX="/usr"
  DISTRO_LOCALSTATEDIR=""
  DISTRO_SYSCONFDIR="/etc"
  DEFAULT_LIB_DIRSPEC="/var" # WTF?!
  export WHEEL_GROUP="wheel"
  ;;
arch)
  DISTRO_PREFIX=""
  DISTRO_EXEC_PREFIX="/usr"
  DISTRO_LOCALSTATEDIR=""
  DISTRO_SYSCONFDIR="/etc"
  DEFAULT_LIB_DIRSPEC="/var" # WTF?!
  export WHEEL_GROUP="wheel"
  ;;
*)
  echo "Unknown Operating System; undefined action; aborted."
  exit 3
  ;;
esac

DISTRO_ETC_DIRSPEC="$DISTRO_SYSCONFDIR"

# Vendor-specific autotool/autoconf,
# only set of violations of lowercase variable names crossing to other scripts
prefix="${prefix:-${DISTRO_PREFIX}}"
sysconfdir="${sysconfdir:-${DISTRO_SYSCONFDIR}}"
exec_prefix="${exec_prefix:-${prefix:-$DISTRO_EXEC_PREFIX}}"
libdir="${libdir:-$DEFAULT_LIB_DIRSPEC}"
libexecdir="${libexecdir:-"${exec_prefix}/libexec"}"
localstatedir="${localstatedir:-"$DISTRO_LOCALSTATEDIR"}"
datarootdir="${datarootdir:-"${prefix}/share"}"
sharedstatedir="${sharedstatedir:-"${prefix}/com"}"
bindir="${bindir:-"${exec_prefix}/bin"}"
sbindir="${sbindir:-"${exec_prefix}/sbin"}"
rundir="${rundir:-"${localstatedir}/run"}"

# Package maintainer-specific

# hesistatingly inserting systemd right here
# systemd really should be a conditional subnet
# systemd
# systemd service filetype
# shellcheck disable=SC2034
SYSTEMD_SERVICE_FILETYPE="service"
# shellcheck disable=SC2034
ETC_SYSTEMD_DIRSPEC="${ETC_DIRSPEC}/systemd"
# shellcheck disable=SC2034
ETC_SYSTEMD_SYSTEM_DIRSPEC="${ETC_SYSTEMD_DIRSPEC}/system"