MDEV-3796 various RPM problems

cmake/cpack_rpm.cmake:
  * mark all cnf files with %config(noreplace)
  * add the forgotten postun script
sql/sys_vars.cc:
  0 for a string variable means "no default. But datadir has the default value.
support-files/rpm/server-postin.sh:
  * use mysqld --help to determine the correct datadir in the presence of my.cnf files
    (better than my_print_defaults, because it considers the correct group set).
  * Only create users, and chown/chmod if it's a fresh install, not an upgrade.
  * only run mysql_install_db if datadir does not exist

cmake/cpack_rpm.cmake

@@ -64,8 +64,10 @@ SET(CPACK_RPM_SPEC_MORE_DEFINE "${CPACK_RPM_SPEC_MORE_DEFINE}
 
 SET(CPACK_RPM_PACKAGE_REQUIRES "MariaDB-common")
 
-SET(CPACK_RPM_server_USER_FILELIST "%ignore /etc" "%ignore /etc/init.d")
+SET(CPACK_RPM_server_USER_FILELIST "%ignore /etc" "%ignore /etc/init.d" "%config(noreplace) /etc/my.cnf.d/*")
 SET(CPACK_RPM_common_USER_FILELIST "%config(noreplace) /etc/my.cnf")
+SET(CPACK_RPM_shared_USER_FILELIST "%config(noreplace) /etc/my.cnf.d/*")
+SET(CPACK_RPM_client_USER_FILELIST "%config(noreplace) /etc/my.cnf.d/*")
 
 SET(CPACK_RPM_client_PACKAGE_OBSOLETES "mysql-client MySQL-client MySQL-OurDelta-client")
 SET(CPACK_RPM_client_PACKAGE_PROVIDES "MariaDB-client MySQL-client mysql-client")
@@ -84,6 +86,7 @@ SET(CPACK_RPM_server_PACKAGE_PROVIDES "MariaDB MariaDB-server MySQL-server confi
 SET(CPACK_RPM_server_PRE_INSTALL_SCRIPT_FILE ${CMAKE_SOURCE_DIR}/support-files/rpm/server-prein.sh)
 SET(CPACK_RPM_server_PRE_UNINSTALL_SCRIPT_FILE ${CMAKE_SOURCE_DIR}/support-files/rpm/server-preun.sh)
 SET(CPACK_RPM_server_POST_INSTALL_SCRIPT_FILE ${CMAKE_SOURCE_DIR}/support-files/rpm/server-postin.sh)
+SET(CPACK_RPM_server_POST_UNINSTALL_SCRIPT_FILE ${CMAKE_SOURCE_DIR}/support-files/rpm/server-postun.sh)
 
 SET(CPACK_RPM_shared_PACKAGE_OBSOLETES "mysql-shared MySQL-shared-standard MySQL-shared-pro MySQL-shared-pro-cert MySQL-shared-pro-gpl MySQL-shared-pro-gpl-cert MySQL-shared MySQL-OurDelta-shared")
 SET(CPACK_RPM_shared_PACKAGE_PROVIDES "MariaDB-shared MySQL-shared mysql-shared libmysqlclient.so.${SHARED_LIB_MAJOR_VERSION} libmysqlclient.so.${SHARED_LIB_MAJOR_VERSION}(libmysqlclient_${SHARED_LIB_MAJOR_VERSION}) libmysqlclient_r.so.${SHARED_LIB_MAJOR_VERSION} libmysqlclient_r.so.${SHARED_LIB_MAJOR_VERSION}(libmysqlclient_${SHARED_LIB_MAJOR_VERSION})")

sql/sys_vars.cc

@@ -568,7 +568,7 @@ static Sys_var_ulong Sys_connect_timeout(
 static Sys_var_charptr Sys_datadir(
        "datadir", "Path to the database root directory",
        READ_ONLY GLOBAL_VAR(mysql_real_data_home_ptr),
-       CMD_LINE(REQUIRED_ARG, 'h'), IN_FS_CHARSET, DEFAULT(0));
+       CMD_LINE(REQUIRED_ARG, 'h'), IN_FS_CHARSET, DEFAULT(mysql_real_data_home));
 
 #ifndef DBUG_OFF
 static Sys_var_dbug Sys_dbug(

support-files/rpm/server-postin.sh

-mysql_datadir=%{mysqldatadir}
-
-# Create data directory
-mkdir -p $mysql_datadir/{mysql,test}
 
 # Make MySQL start/shutdown automatically when the machine does it.
 if [ $1 = 1 ] ; then
   if [ -x /sbin/chkconfig ] ; then
           /sbin/chkconfig --add mysql
   fi
-fi
 
-# Create a MySQL user and group. Do not report any problems if it already
-# exists.
-groupadd -r %{mysqld_group} 2> /dev/null || true
-useradd -M -r -d $mysql_datadir -s /bin/bash -c "MySQL server" -g %{mysqld_group} %{mysqld_user} 2> /dev/null || true 
-# The user may already exist, make sure it has the proper group nevertheless (BUG#12823)
-usermod -g %{mysqld_group} %{mysqld_user} 2> /dev/null || true
+  mysql_dirs=(`%{_sbindir}/mysqld --verbose --help 2>/dev/null|sed -ne 's/^\(basedir\|datadir\)[[:space:]]*\(.*\)$/\2/p'`)
+  basedir="${mysql_dirs[0]}"
+  datadir="${mysql_dirs[1]}"
+  # datadir may be relative to a basedir!
+  if expr $datadir : / > /dev/null; then
+    mysql_datadir=$datadir
+  else
+    mysql_datadir=$basedir/$datadir
+  fi
+
+  # Create a MySQL user and group. Do not report any problems if it already
+  # exists.
+  groupadd -r %{mysqld_group} 2> /dev/null || true
+  useradd -M -r -d $mysql_datadir -s /bin/bash -c "MySQL server" -g %{mysqld_group} %{mysqld_user} 2> /dev/null || true 
+  # The user may already exist, make sure it has the proper group nevertheless (BUG#12823)
+  usermod -g %{mysqld_group} %{mysqld_user} 2> /dev/null || true
 
-# Change permissions so that the user that will run the MySQL daemon
-# owns all database files.
-chown -R %{mysqld_user}:%{mysqld_group} $mysql_datadir
+  # Change permissions so that the user that will run the MySQL daemon
+  # owns all database files.
+  chown -R %{mysqld_user}:%{mysqld_group} $mysql_datadir
 
-# Initiate databases
-%{_bindir}/mysql_install_db --rpm --user=%{mysqld_user}
+  if [ ! -e $mysql_datadir ]; then
+    # Create data directory
+    mkdir -p $mysql_datadir/{mysql,test}
 
-# Upgrade databases if needed would go here - but it cannot be automated yet
+    # Initiate databases
+    %{_bindir}/mysql_install_db --rpm --user=%{mysqld_user}
+  fi
 
-# Change permissions again to fix any new files.
-chown -R %{mysqld_user}:%{mysqld_group} $mysql_datadir
+  # Change permissions again to fix any new files.
+  chown -R %{mysqld_user}:%{mysqld_group} $mysql_datadir
 
-# Fix permissions for the permission database so that only the user
-# can read them.
-chmod -R og-rw $mysql_datadir/mysql
+  # Fix permissions for the permission database so that only the user
+  # can read them.
+  chmod -R og-rw $mysql_datadir/mysql
+fi
 
 # install SELinux files - but don't override existing ones
 SETARGETDIR=/etc/selinux/targeted/src/policy