MDEV-6284: Sync mariadb-server maintainer scripts as much as possible

There are still some differences in due to systemd and service triggers,
but these differences make sense and are likely to be synced the other
way later so that downstream Debian official packaging adopts them.

The synced changes include among others:
- https://salsa.debian.org/mariadb-team/mariadb-10.4/-/commit/9f49e4b494f3dad8c403972996f7a1ebceb4b34f
- https://salsa.debian.org/mariadb-team/mariadb-10.4/-/commit/6440c0d6e75aeda134f4f942eee4fbfd62b1ce20
- https://salsa.debian.org/mariadb-team/mariadb-10.4/-/commit/6e5ee72d647744bf84c42e02c3dfe888912e739e
- https://salsa.debian.org/mariadb-team/mariadb-10.4/-/commit/e62e67ae4b7679c43e80a20ab3ba3c51f01f0714
- https://salsa.debian.org/mariadb-team/mariadb-10.4/-/commit/df2415a53d5604755768f00aad0c640df1ad815c
- https://salsa.debian.org/mariadb-team/mariadb-10.4/-/commit/643558da74990f8648b3c86039e253dbae337c84

debian/mariadb-server-10.5.postinst

-#!/bin/bash -e
+#!/bin/bash
+set -e
 
 . /usr/share/debconf/confmodule
 
@@ -12,6 +13,7 @@ export PATH=$PATH:/sbin:/usr/sbin:/bin:/usr/bin
 
 # This command can be used as pipe to syslog. With "-s" it also logs to stderr.
 ERR_LOGGER="logger -p daemon.err -t mariadb-server-$MAJOR_VER.postinst -i"
+# Specify syslog tag name so it is clear the entry came from this postinst script.
 # This will make an error in a logged command immediately apparent by aborting
 # the install, rather than failing silently and leaving a broken install.
 set -o pipefail
@@ -31,7 +33,6 @@ case "$1" in
     mysql_statedir=/usr/share/mysql
     mysql_datadir=/var/lib/mysql
     mysql_logdir=/var/log/mysql
-    mysql_rundir=/var/run/mysqld
     mysql_cfgdir=/etc/mysql
     mysql_upgradedir=/var/lib/mysql-upgrade
 
@@ -56,7 +57,7 @@ case "$1" in
           mv "$savelink" "$targetdir"
         else
           # this should never even happen, but just in case...
-          mysql_tmp=`mktemp -d -t mysql-symlink-restore-XXXXXX`
+          mysql_tmp=$(mktemp -d -t mysql-symlink-restore-XXXXXX)
           echo "this is very strange!  see $mysql_tmp/README..." >&2
           mv "$targetdir" "$mysql_tmp"
           cat << EOF > "$mysql_tmp/README"
@@ -79,17 +80,17 @@ EOF
     done
 
     # Ensure the existence and right permissions for the database and
-    # log files.
-    if [ ! -d "$mysql_statedir" -a ! -L "$mysql_statedir" ]; then mkdir "$mysql_statedir"; fi
-    if [ ! -d "$mysql_datadir"  -a ! -L "$mysql_datadir" ]; then mkdir "$mysql_datadir" ; fi
-    if [ ! -d "$mysql_logdir"   -a ! -L "$mysql_logdir"  ]; then mkdir "$mysql_logdir"  ; fi
+    # log files. Use mkdir option 'Z' to create with correct SELinux context.
+    if [ ! -d "$mysql_statedir" ] && [ ! -L "$mysql_statedir" ]; then mkdir -Z "$mysql_statedir"; fi
+    if [ ! -d "$mysql_datadir"  ] && [ ! -L "$mysql_datadir" ]; then mkdir -Z "$mysql_datadir" ; fi
+    if [ ! -d "$mysql_logdir"   ] && [ ! -L "$mysql_logdir"  ]; then mkdir -Z "$mysql_logdir"  ; fi
     # When creating an ext3 jounal on an already mounted filesystem like e.g.
     # /var/lib/mysql, you get a .journal file that is not modifyable by chown.
     # The mysql_statedir must not be writable by the mysql user under any
     # circumstances as it contains scripts that are executed by root.
     set +e
     chown -R 0:0 $mysql_statedir
-    find $mysql_datadir ! -uid $(id -u mysql) -print0 | xargs -0 -r chown mysql
+    find $mysql_datadir ! -uid "$(id -u mysql)" -print0 | xargs -0 -r chown mysql
     chown -R mysql:adm $mysql_logdir
     chmod 2750 $mysql_logdir
     set -e
@@ -105,7 +106,7 @@ EOF
     # Clean up old flags before setting new one
     rm -f $mysql_datadir/debian-*.flag
     # Flag data dir to avoid downgrades
-    touch $mysql_datadir/debian-10.5.flag
+    touch "$mysql_datadir/debian-$MAJOR_VER.flag"
 
     # initiate databases. Output is not allowed by debconf :-(
     # This will fail if we are upgrading an existing database; in this case
@@ -115,12 +116,12 @@ EOF
     # Debian: can safely run on upgrades with existing databases
     set +e
     bash /usr/bin/mysql_install_db --rpm --cross-bootstrap --user=mysql \
-                                   --disable-log-bin --skip-test-db 2>&1 | \
+                                   --disable-log-bin  --skip-test-db 2>&1 | \
                                    $ERR_LOGGER
     set -e
 
     # To avoid downgrades.
-    touch $mysql_statedir/debian-$MAJOR_VER.flag
+    touch "$mysql_statedir/debian-$MAJOR_VER.flag"
 
     # On new installations root user can connect via unix_socket.
     # But on upgrades, scripts rely on debian-sys-maint user and
@@ -130,6 +131,9 @@ EOF
     # --defaults-file option for tools (for the sake of upgrades)
     # and thus need /etc/mysql/debian.cnf to exist, even if it's empty.
     dc=$mysql_cfgdir/debian.cnf;
+    if [ ! -d "$mysql_cfgdir" ]; then
+      install -o 0 -g 0 -m 0755 -d $mysql_cfgdir
+    fi
     if [ ! -e "$dc" ]; then
         cat /dev/null > $dc
         echo "# Automatically generated for Debian scripts. DO NOT TOUCH!" >>$dc
@@ -146,11 +150,11 @@ EOF
     # any profile installed and maintained by users themselves.
     profile="/etc/apparmor.d/usr.sbin.mysqld"
     if [ -f "$profile" ] && aa-status --enabled 2>/dev/null; then
-        if grep -q /usr/sbin/mysqld "$profile" 2>/dev/null ; then
-            apparmor_parser -r "$profile" || true
-        else
-            echo "/usr/sbin/mysqld { }" | apparmor_parser --remove 2>/dev/null || true
-	fi
+      if grep -q /usr/sbin/mysqld "$profile" 2>/dev/null ; then
+        apparmor_parser -r "$profile" || true
+      else
+        echo "/usr/sbin/mysqld { }" | apparmor_parser --remove 2>/dev/null || true
+      fi
     fi
 
     # copy out any mysqld_safe settings
@@ -189,5 +193,3 @@ if [ -x "$(command -v deb-systemd-helper)" ]; then
 fi
 
 #DEBHELPER#
-
-exit 0

debian/mariadb-server-10.5.postrm

-#!/bin/bash -e
+#!/bin/bash
+set -e
 
 . /usr/share/debconf/confmodule
 
+# Automatically set version to ease maintenance of this file
+MAJOR_VER="${DPKG_MAINTSCRIPT_PACKAGE#mariadb-server-}"
+
 if [ -n "$DEBIAN_SCRIPT_DEBUG" ]; then set -v -x; DEBIAN_SCRIPT_TRACE=1; fi
 ${DEBIAN_SCRIPT_TRACE:+ echo "#42#DEBUG# RUNNING $0 $*" 1>&2 }
 
@@ -37,17 +41,18 @@ case "$1" in
 esac
 
 #
-# - Do NOT purge logs or data if another mysql-sever* package is installed (#307473)
+# - Purge logs and data only if they are ours (#307473)
 # - Remove the mysql user only after all his owned files are purged.
+# - Cleanup the initscripts only if this was the last provider of them
 #
-if [ "$1" = "purge" -a ! \( -x /usr/sbin/mysqld -o -L /usr/sbin/mysqld \) ]; then
+if [ "$1" = "purge" ] && [ -f "/var/lib/mysql/debian-$MAJOR_VER.flag" ]; then
   # we remove the mysql user only after all his owned files are purged
   rm -f /var/log/mysql.{log,err}{,.0,.[1234567].gz}
   rm -rf /var/log/mysql
 
-  db_input high mariadb-server-10.5/postrm_remove_databases || true
+  db_input high "mariadb-server-$MAJOR_VER/postrm_remove_databases" || true
   db_go || true
-  db_get mariadb-server-10.5/postrm_remove_databases || true
+  db_get "mariadb-server-$MAJOR_VER/postrm_remove_databases" || true
   if [ "$RET" = "true" ]; then
     # never remove the debian.cnf when the databases are still existing
     # else we ran into big trouble on the next install!
@@ -56,13 +61,19 @@ if [ "$1" = "purge" -a ! \( -x /usr/sbin/mysqld -o -L /usr/sbin/mysqld \) ]; the
     # directory with file system data. See #829491 for details and
     # #608938 for potential mysql-server leftovers which erroneously
     # had been renamed.
-    find /var/lib/mysql -mindepth 1 \
-         -not -path '*/lost+found/*'     -not -name 'lost+found' \
-         -not -path '*/lost@002bfound/*' -not -name 'lost@002bfound' \
-         -delete
-    # "|| true" still needed as rmdir still exits with non-zero if
-    # /var/lib/mysql is a mount point
-    rmdir --ignore-fail-on-non-empty /var/lib/mysql || true
+    # Attempt removal only if the directory hasn't already been removed
+    # by dpkg to avoid failing on "No such file or directory" errors.
+    if [ -d /var/lib/mysql ]
+    then
+      find /var/lib/mysql -mindepth 1 \
+           -not -path '*/lost+found/*'     -not -name 'lost+found' \
+           -not -path '*/lost@002bfound/*' -not -name 'lost@002bfound' \
+           -delete
+
+      # "|| true" still needed as rmdir still exits with non-zero if
+      # /var/lib/mysql is a mount point
+      rmdir --ignore-fail-on-non-empty /var/lib/mysql || true
+    fi
     rm -rf /var/run/mysqld # this directory is created by the init script, don't leave behind
     userdel mysql || true
   fi
@@ -70,5 +81,3 @@ if [ "$1" = "purge" -a ! \( -x /usr/sbin/mysqld -o -L /usr/sbin/mysqld \) ]; the
 fi
 
 #DEBHELPER#
-
-exit 0

debian/mariadb-server-10.5.preinst

@@ -9,6 +9,14 @@
 
 . /usr/share/debconf/confmodule
 
+# Automatically set version to ease maintenance of this file
+MAJOR_VER="${DPKG_MAINTSCRIPT_PACKAGE#mariadb-server-}"
+
+# Just kill the invalid insserv.conf.d directory without fallback
+if [ -d "/etc/insserv.conf.d/mariadb/" ]; then
+    rm -rf "/etc/insserv.conf.d/mariadb/"
+fi
+
 if [ -n "$DEBIAN_SCRIPT_DEBUG" ]; then set -v -x; DEBIAN_SCRIPT_TRACE=1; fi
 ${DEBIAN_SCRIPT_TRACE:+ echo "#42#DEBUG# RUNNING $0 $*" 1>&2 }
 
@@ -41,7 +49,7 @@ stop_server() {
 
 ################################ main() ##########################
 
-this_version=10.5
+this_version=$MAJOR_VER
 max_upgradeable_version=5.7
 
 # Check if a flag file is found that indicates a previous MariaDB or MySQL
@@ -53,12 +61,12 @@ do
   # The for loop leaves $flag as the query string if there are no results,
   # so the check below is needed to stop further processing when there are
   # no real results.
-  if [ $flag = "$mysql_datadir/debian-*.flag" ]
+  if [ "$flag" = "$mysql_datadir/debian-*.flag" ]
   then
     break
   fi
 
-  flag_version=`echo $flag | sed 's/.*debian-\([0-9\.]\+\).flag/\1/'`
+  flag_version=$(echo "$flag" | sed 's/.*debian-\([0-9\.]\+\).flag/\1/')
 
   # Initialize value if empty
   if [ -z "$found_version" ]
@@ -85,6 +93,15 @@ done
 if [ ! -z "$found_version" ]
 then
 
+  # MySQL 8.0 in Ubuntu has a bug in packaging and the file is name wrongly
+  # 'debian-5.7.flag', so in case '5.7' was encountered an extra check needs to
+  # be done to see is there is a file called undo_001, which is a sign of 8.0.
+  if [ "$found_version" == "5.7" ] && [ -f "$mysql_datadir/undo_001" ]
+  then
+    # Seems to be a 8.0, flag has wrongly 5.7 (know bug)
+    found_version=8.0
+  fi
+
   echo "$mysql_datadir: found previous version $found_version"
 
   if dpkg --compare-versions "$found_version" '>>' "$this_version"
@@ -105,17 +122,17 @@ fi
 # Instead simply move the old datadir and create a new for this_version.
 if [ ! -z "$downgrade_detected" ]
 then
-  db_input critical mariadb-server-10.5/old_data_directory_saved || true
+  db_input critical "mariadb-server-$MAJOR_VER/old_data_directory_saved" || true
   db_go
   echo "The file $mysql_datadir/debian-$found_version.flag indicates a" 1>&2
   echo "version that cannot automatically be upgraded. Therefore the" 1>&2
   echo "previous data directory will be renamed to $mysql_datadir-$found_version and" 1>&2
   echo "a new data directory will be initialized at $mysql_datadir." 1>&2
   echo "Please manually export/import your data (e.g. with mysqldump) if needed." 1>&2
-  mv -f $mysql_datadir $mysql_datadir-$found_version
+  mv -f "$mysql_datadir" "$mysql_datadir-$found_version"
   # Also move away the old debian.cnf file that included credentials that are
   # no longer valid
-  mv -f /etc/mysql/debian.cnf /etc/mysql/debian.cnf-$found_version
+  mv -f /etc/mysql/debian.cnf "/etc/mysql/debian.cnf-$found_version"
 fi
 
 # to be sure
@@ -124,7 +141,7 @@ stop_server
 # If we use NIS then errors should be tolerated. It's up to the
 # user to ensure that the mysql user is correctly setup.
 # Beware that there are two ypwhich one of them needs the 2>/dev/null!
-if test -n "`which ypwhich 2>/dev/null`"  &&  ypwhich >/dev/null 2>&1; then
+if test -n "$(which ypwhich 2>/dev/null)"  &&  ypwhich >/dev/null 2>&1; then
   set +e
 fi
 
@@ -164,16 +181,18 @@ set -e
 # if there's a symlink, let's store where it's pointing, because otherwise
 # it's going to be lost in some situations
 for dir in DATADIR LOGDIR; do
-    checkdir=`eval echo "$"$dir`
-    if [ -L "$checkdir" ]; then
-	mkdir -p "$mysql_upgradedir"
-	cp -dT "$checkdir" "$mysql_upgradedir/$dir.link"
-    fi
+  checkdir=$(eval echo "$"$dir)
+  if [ -L "$checkdir" ]; then
+    # Use mkdir option 'Z' to create with correct SELinux context.
+    mkdir -pZ "$mysql_upgradedir"
+    cp -dT "$checkdir" "$mysql_upgradedir/$dir.link"
+  fi
 done
 
 # creating mysql home directory
-if [ ! -d $mysql_datadir -a ! -L $mysql_datadir ]; then
- 	mkdir $mysql_datadir
+if [ ! -d $mysql_datadir ] && [ ! -L $mysql_datadir ]; then
+	# Use mkdir option 'Z' to create with correct SELinux context.
+  mkdir -Z $mysql_datadir
 fi
 
 # checking disc space
@@ -191,7 +210,7 @@ fi
 # The "set +e" is necessary as e.g. a ".journal" of a ext3 partition is
 # not chgrp'able (#318435).
 set +e
-find $mysql_datadir ! -uid $(id -u mysql) -print0 | xargs -0 -r chown mysql
+find $mysql_datadir ! -uid "$(id -u mysql)" -print0 | xargs -0 -r chown mysql
 find $mysql_datadir -follow -not -group mysql -print0 2>/dev/null \
   | xargs -0 --no-run-if-empty chgrp mysql
 set -e
@@ -200,5 +219,3 @@ set -e
 db_stop
 
 #DEBHELPER#
-
-exit 0

debian/mariadb-server-10.5.prerm

-#!/bin/bash
-
+#!/bin/sh
 set -e
 
-. /usr/share/debconf/confmodule
-
-if [ -n "$DEBIAN_SCRIPT_DEBUG" ]; then set -v -x; DEBIAN_SCRIPT_TRACE=1; fi
-${DEBIAN_SCRIPT_TRACE:+ echo "#42#DEBUG# RUNNING $0 $*" 1>&2 }
-
 #DEBHELPER#