A script to fetch updates for Slackware stable

getupdates

#!/bin/sh
#
# getupdates (0.9.6) - A script to fetch updates for Slackware stable
#
#           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
#                   Version 2, December 2004
#
# Copyright (C) 2017 Ruari Oedegaard, Oslo, Norway
# 
# Everyone is permitted to copy and distribute verbatim or modified
# copies of this license document, and changing it is allowed as long
# as the name is changed.
#
#            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
#   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
#
#  0. You just DO WHAT THE FUCK YOU WANT TO.

# Automatically gather some information about the Slackware release

case `uname -m` in
    i?86) SLACKTYPE="slackware" ;;
  x86_64) SLACKTYPE="slackware64" ;;
     arm) SLACKTYPE="slackwarearm" ;;
       *) printf "\n\n$SLACKTYPE is not supported.\n" ; exit 1 ;;
esac

SLACKVERSION=`awk -F'[ .]' '{print $2"."$3}' /etc/slackware-version`

# Read the 3 variables from the environment or set them to defaults

SLACKMIRROR=${SLACKMIRROR:-https://mirrors.slackware.com/slackware}
LOCALPATCHDIR=${LOCALPATCHDIR:-$HOME/patches}
SAVEMETADATA=${SAVEMETADATA:-NO}

# Create working directory structure if not yet present
mkdir -p "$LOCALPATCHDIR/.metadata"
cd "$LOCALPATCHDIR/.metadata"

# Optionally clean temporary update metadata on exit
cleanmeta ()
{
  if [ "$SAVEMETADATA" = "NO" ]; then
    rm -fr "$LOCALPATCHDIR/.metadata"
  else
    echo "Note: The metadata directory (\"$LOCALPATCHDIR/.metadata\") was retained"
  fi
}

# Fetch the latest package checksums
rm -f CHECKSUMS.md5*
if ! wget -q $SLACKMIRROR/${SLACKTYPE}-${SLACKVERSION}/patches/CHECKSUMS.md5; then
  echo "There were problems accessing $SLACKMIRROR/patches/CHECKSUMS.md5" 2>&1
  cleanmeta
  exit 1
fi

# See if cryptographic verification is possible
if command -v gpg >/dev/null 2>&1; then
  if gpg --list-keys 2>/dev/null | grep -Fq '[email protected]'; then
    SIGNATURE=YES
  else
    SIGNATURE=NO
  fi
else
  SIGNATURE=NO
fi

# If possible verify CHECKSUMS.md5's signature
if [ "$SIGNATURE" = "YES" ]; then
  wget -q $SLACKMIRROR/${SLACKTYPE}-${SLACKVERSION}/patches/CHECKSUMS.md5.asc
  if ! gpg --verify CHECKSUMS.md5.asc 2>/dev/null; then
    echo "ERROR: Could not verify CHECKSUMS.md5! Aborting!" >&2
    cleanmeta
    exit 1
  fi
fi

# If there is no blacklist file present, make a blank one as the file
# is expected and read by this script later on
if [ ! -e "$LOCALPATCHDIR/blacklist" ]; then
  touch "$LOCALPATCHDIR/blacklist"
  # Provide some guidence on blacklist creation to the first time user
  cat <<EOBL> "$LOCALPATCHDIR/blacklist.README.txt"
To blacklist updates, open the blacklist file found in this directory 
and add a regex for any package updates you wish to avoid. The file will 
be read by grep (in extended regex mode) to filter out updates.

NOTE: Do not add any any other lines (including comments or blank 
lines) to the blacklist file as these extra lines will be counted as a
regex, potentially matching and blocking updates!

e.g. to block by package name, use the following format:
packagename(-[[:alnum:]\.\+_]+){3}

Simply adjust "packagename" to the name of the package you wish to
block, e.g. to block kernel-huge-smp:
kernel-huge-smp(-[[:alnum:]\.\+_]+){3}

Or to block all kernel packages:
^kernel

To block updates to all packages created by Alien Bob (e.g. to preserve
multilib packages), you could do the following:
[0-9]+alien$
EOBL
fi

# Create a regex filter of pre-installed packages that aren't
# blacklisted
/bin/ls /var/log/packages \
  | grep -Evf "$LOCALPATCHDIR/blacklist" \
  | sed -nr 's#^([[:graph:]]+)(-[[:alnum:]\.\+_]+){3}$#[[:alnum:]]{32}  \1(-[[:alnum:]\\.\\+_]+){3}\\.t.z(\\.asc)*#p' \
  > filter

# Filter CHECKSUMS.md5 for only the upgrades we are interested in
sed -rn 's#([[:alnum:]]{32}  )\./packages/#\1#p' CHECKSUMS.md5 \
  | grep -xEf filter \
  > md5sums.new

# Exit if none of the potential package updates we might want are
# present on the server
if ! grep -q '.' md5sums.new; then
  echo "No updates available"
  cleanmeta
  exit 0
fi

# Create md5sums for any package updates that are already present
# locally
( cd "$LOCALPATCHDIR"; md5sum *.t?z* 2>/dev/null ) \
  > md5sums.local

# Syncronise package updates, only if there are changes
if diff md5sums.local md5sums.new > md5sums.diff; then
  echo "The directory \"$LOCALPATCHDIR\" was already up to date."
  cleanmeta
  exit 0
else
  for old in $( sed -rn 's#^< [[:alnum:]]{32}  ##p' md5sums.diff ); do
    rm -v "$LOCALPATCHDIR/$old"
  done
  for new in $( sed -rn 's#^> [[:alnum:]]{32}  ##p' md5sums.diff ); do
    wget $SLACKMIRROR/${SLACKTYPE}-${SLACKVERSION}/patches/packages/$new -P "$LOCALPATCHDIR"
  done
fi

# Provide a warning for when cryptographic verification is not possible
# (to use below)
verificationwarning ()
{
  echo "Note: Because the [email protected] signing key was not available"  >&2
  echo "the packages cannot be cryptographically verified. Import the key to"  >&2
  echo "rectify this situation." >&2
}

# Use md5sums to check that the files downloaded correctly
cd "$LOCALPATCHDIR"
if md5sum --quiet -c .metadata/md5sums.new; then
  echo "The directory \"$LOCALPATCHDIR\" is now up to date!"
else
  if [ "$SIGNATURE" = "YES" ]; then
    echo "Note: Exiting early due to failed checksum(s), without checking signatures!" >&2
    cleanmeta
    exit 1
  else
    # Note: The md5sum check will print errors itself but add a warning
    # about cryptographic verification not being possible anyway.
    verificationwarning
    cleanmeta
    exit 1
  fi
fi

# Check security signatures, if the Slackware signing key is available
if [ "$SIGNATURE" = "YES" ]; then
  echo -n "Checking security signatures ... "
  for sig in *.asc; do
    if ! gpg --verify $sig 2>/dev/null; then
      echo -e "\nERROR: Verification failed while testing \"$sig\"! Further processing has been aborted!" >&2
      cleanmeta
      exit 1
    fi
  done
  echo "Done!"
  echo "No problems detected. :)"
else
  verificationwarning
fi

# Final cleanup if not done elsewhere
cleanmeta