Merge pull request #2303 from jsmeix/enhanced_make_syslinux_config_fu…

…nction_to_specify_boot_default_related_to_issue2276

Enhanced recovery system BIOS boot default settings for USB and ISO:
For OUTPUT=ISO the user can now explicitly specify
what to boot by default when booting the ISO on BIOS systems via
ISO_DEFAULT="boothd0" to boot from the first disk and
ISO_DEFAULT="boothd1" to boot from the second disk.
For OUTPUT=USB the user can now explicitly specify
what to boot by default when booting the disk on BIOS systems via
USB_BIOS_BOOT_DEFAULT="boothd0" to boot from the first disk.
The default USB_BIOS_BOOT_DEFAULT="" boots the second disk.
Cf. #2276 (comment)

usr/share/rear/conf/default.conf

@@ -604,15 +604,15 @@ RAMDISK_SUFFIX="$HOSTNAME"
 ##
 # OUTPUT=ISO stuff
 ##
-# ISO produces files suitable for booting with isolinux and assumes that the result
-# will be written sequentially to a read-only media with limited size (e.g. optical media)
-
+# OUTPUT=ISO produces files suitable for booting with SYSLINUX/ISOLINUX and assumes that the result
+# will be written sequentially to a read-only medium with limited size (e.g. optical medium like CD-ROM).
+#
 # Default "local" ISO directory (usually /var/lib/rear/output). However, to avoid duplicate ISO images when
 # also using the OUTPUT_URL variable with a file syntax, it is then better only to use ISO_DIR.
 # Keep in mind that ISO_DIR works only with an absolute directory path and does not replace OUTPUT_URL
 # which supports the NETFS syntax (to copy the ISO image across the network).
 ISO_DIR=$VAR_DIR/output
-
+#
 # Default ISO label:
 # When the backup is split on multiple ISOs (cf. ISO_MAX_SIZE below)
 # the first ISO 'rear-HOSTNAME.iso' has the label $ISO_VOLID
@@ -625,11 +625,11 @@ ISO_DIR=$VAR_DIR/output
 # filesystem that only support short volume labels the ISO_VOLID value
 # must be appropriately specified in /etc/rear/local.conf
 ISO_VOLID="RELAXRECOVER"
-
+#
 # How to find isolinux.bin.
 # Possible values are "" (meaning search for it) or "/path/to/isolinux.bin"
 ISO_ISOLINUX_BIN=""
-
+#
 # Maximum size of generated ISO images.
 # Multiple ISO images will be generated if the size exceeds ISO_MAX_SIZE.
 # The ISO_MAX_SIZE value is specified in MiB
@@ -651,7 +651,7 @@ ISO_ISOLINUX_BIN=""
 # Accordingly when ISO_MAX_SIZE is set the mkrescue workflow is forbidden
 # to be on the safe side to not possibly destroy an existing backup.
 ISO_MAX_SIZE=
-
+#
 # How to find mkisofs:
 # Guess the common names mkisofs or genisoimage
 # script in prep stage will verify this and complain if not found
@@ -662,38 +662,59 @@ ISO_MAX_SIZE=
 # xorrisofs is now used as the preferred method for generating the iso image
 # with mkisofs and genisoimage as second and third option
 ISO_MKISOFS_BIN="$( type -p xorrisofs || type -p mkisofs || type -p genisoimage )"
-
+#
 # Additional options passed to the $ISO_MKISOFS_BIN binary
 ISO_MKISOFS_OPTS=""
-
+#
 # Which files to include in the ISO image:
 ISO_FILES=()
-
+#
 # Prefix name for ISO images without the .iso suffix.
 # This might get a number appended (for splitting data onto multiple CDs).
 ISO_PREFIX="rear-$HOSTNAME"
-
-# Default boot option for ISO image. If unset, system will boot from first HD
-# by default. This is useful in almost all cases. If empty "boothd" will be used.
-# Change this only, if you are about to automate things
-# E.g. ISO_DEFAULT=manual
-# This will start the REAR system and you can connect via ssh and issue 'rear recover'
-ISO_DEFAULT=boothd
-
-# The ISO_RECOVER_MODE variable can be set to "" (blank: default), "unattended" (export mode:
-# where rear will not wait for a question, but is only meant for experts and testing purposes),
 #
-ISO_RECOVER_MODE=
+# Default boot option (i.e. what gets booted automatically after some timeout)
+# when SYSLINUX boots the ISO image on BIOS systems.
+# This variable ISO_DEFAULT should be better named ISO_BIOS_BOOT_DEFAULT
+# (cf. USB_BIOS_BOOT_DEFAULT below) but we won't rename existing config variables
+# to avoid regressions for users who use existing config variable names
+# cf. https://github.com/rear/rear/pull/2293#issuecomment-564439509
+# If ISO_DEFAULT is unset or empty or only blanks "boothd" is used by default.
+# ISO_DEFAULT="boothd" is an automatism that intends to boot from the original first disk.
+# In case of ISOLINUX "boothd" means to boot from the first disk 'boothd0' because
+# usually ISOLINUX is used for booting from CD-ROM which is usually not the first disk
+# so that the original first disk still is the first disk when booting the ISO from CD-ROM.
+# In case of EXTLINUX "boothd" would mean to boot from the second disk 'boothd1' because
+# usually when EXTLINUX is used the device with the ISO would be the first disk 
+# and the original first disk would become the second disk (cf. USB_BIOS_BOOT_DEFAULT below).
+# ISO_DEFAULT="boothd0" boots from the first disk.
+# ISO_DEFAULT="boothd1" boots from the second disk.
+# The ISO_DEFAULT values 'boothd' 'boothd0' 'boothd1' are only supported
+# when the SYSLINUX module 'chain.c32' for chain booting is available.
+# ISO_DEFAULT="manual" boots the ReaR recovery system in normal mode
+# where one must manually log in as 'root', manually type "rear recover", and manually reboot.
+# ISO_DEFAULT="automatic" boots the ReaR recovery system with the 'auto_recover' kernel command line option
+# that runs "rear recover" automatically without automated reboot (see "man rear").
+# For details see the make_syslinux_config function in lib/bootloader-functions.sh
+ISO_DEFAULT="boothd"
+#
+# ISO_RECOVER_MODE="unattended" boots the ReaR recovery system with the 'unattended' kernel command line option
+# that runs "rear recover" automatically plus automated reboot after successful rear recover (see "man rear").
+# Together with ISO_DEFAULT="automatic" full-automated recovery happens when the ISO image is booted
+# which could result an endless full-automated recovery cycle when the ISO is booted by default
+# (e.g. when the device with the ISO is the first one in the BIOS boot order list).
+# The default ISO_RECOVER_MODE="" results the normal behaviour:
+ISO_RECOVER_MODE=""
 
 ##
 # OUTPUT=USB stuff
 ##
-# USB produces files suitable for booting with extlinux, USB sticks are just the main use for this
+# OUTPUT=USB produces files suitable for booting with SYSLINUX/EXTLINUX from a disk device.
+# USB sticks and USB disks are the main use case for this.
+# "USB" also means any local block-storage device and includes eSATA and other external disks.
 # The device is also made bootable and a boot loader installed.
 # The device must be partitioned and formatted with an ext* file system.
 #
-# NOTE: "USB" means any local block-storage device and includes also eSATA and other external disks
-#
 # The device to use, set automatically by BACKUP=NETFS and BACKUP_URL=usb:///dev/sdb1
 USB_DEVICE=
 #
@@ -766,6 +787,18 @@ USB_PARTITION_ALIGN_BLOCK_SIZE="8"
 # USB_PARTITION_ALIGN_BLOCK_SIZE chunk:
 USB_UEFI_PART_SIZE="400"
 #
+# Default boot option (i.e. what gets booted automatically after some timeout)
+# when EXTLINUX boots the USB stick or USB disk or other disk device on BIOS systems.
+# USB_BIOS_BOOT_DEFAULT="boothd0" boots from 'boothd0' which is usually the same disk
+# wherefrom currently EXTLINUX is booting so that this results usually a booting loop.
+# The default USB_BIOS_BOOT_DEFAULT="" boots from the second disk 'boothd1'
+# which should be the original first local harddisk because usually when booting
+# from USB stick or USB disk or other disk device this boot device is the first disk
+# and the original first local harddisk disk becomes the second disk.
+# USB_BIOS_BOOT_DEFAULT is only supported when the SYSLINUX module 'chain.c32' for chain booting is available.
+# For details see output/USB/Linux-i386/300_create_extlinux.sh
+USB_BIOS_BOOT_DEFAULT=""
+#
 # Resulting files that should be copied onto the USB stick:
 USB_FILES=()
 #
@@ -790,19 +823,7 @@ USB_SUFFIX=""
 # What is more than USB_RETAIN_BACKUP_NR gets automatically removed.
 # This setting is ignored when USB_SUFFIX is set (see above).
 USB_RETAIN_BACKUP_NR=2
-
-# Define the default WORKFLOW for the udev handler (empty to disable)
-UDEV_WORKFLOW=mkrescue
 #
-# Beep when udev handler has finished
-UDEV_BEEP=y
-#
-# Suspend the (USB) device when udev handler has finished ?
-UDEV_SUSPEND=y
-#
-# Turn the UID led on during udev workflow
-UDEV_UID_LED=y
-
 # Variable will probably be filled automatically
 # if an USB device was manually mounted to avoid recursive backups:
 AUTOEXCLUDE_USB_PATH=()
@@ -1103,6 +1124,21 @@ FULLBACKUPDAY=()
 # when it is older than 7 days ago:
 FULLBACKUP_OUTDATED_DAYS="7"
 
+##
+# UDEV workflow stuff
+##
+# Define the default WORKFLOW for the udev handler (empty to disable)
+UDEV_WORKFLOW=mkrescue
+#
+# Beep when udev handler has finished
+UDEV_BEEP=y
+#
+# Suspend the (USB) device when udev handler has finished ?
+UDEV_SUSPEND=y
+#
+# Turn the UID led on during udev workflow
+UDEV_UID_LED=y
+
 # Program files (as found in PATH) to include in the rescue/recovery system:
 # These progs are optional, if they are missing, nothing happens
 PROGS=( )

usr/share/rear/conf/templates/rear.help

@@ -1,21 +1,21 @@
-09Relax-and-Recover recovery mode07
-01~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~07
-0fRelax-and-Recover07 is a disaster recovery and system migration tool.
+Relax-and-Recover recovery mode
+===============================
+Relax-and-Recover (ReaR) is a disaster recovery tool.
 
-This help is part of the rescue image, you are here because you plan to recover
-or migrate a previously made backup of your system, including the disk layout
-as it was when the rescue environment was created.
+This help is part of the ReaR rescue image. You are here when you need
+to recover your system by restoring a backup that you had made before
+plus recreating the disk layout (partitions, filesystems) as it was
+when you had made the rescue image (via "rear mkbackup/mkrescue).
 
-The menu gives an overview of the various system rescue environments stored on
-the boot media you used for booting this screen (either USB, PXE or ISO). For
-each of the systems one or more rescue environments are stored, when browsing
-through the images more information is shown below the menu.
+The menu lists the rescue images (or recovery environments) stored
+on this boot medium (USB, PXE, ISO) that is used to boot this menu.
+For each system one or more rescue images can be stored.
+When browsing through them more information is shown.
 
-Once you boot into one of the rescue images, you can start recover the system.
-You can do this by typing: 0erear recover07
-
-cfCAUTION:0f Once you start recovery, it is likely the actions cannot be undone and
-         you may loose anything stored on the physical disks of the system.07
+After you booted into a ReaR rescue image, you can recover that system
+by logging in as 'root' and starting the recovery with "rear recover".
 
+CAUTION: Once you launched the recovery, its actions cannot be undone.
+         It will overwrite all what is stored on the system disk(s).
 
 Press ENTER to return to the menu.

usr/share/rear/lib/bootloader-functions.sh

@@ -112,12 +112,10 @@ function set_syslinux_features {
     FEATURE_SYSLINUX_MENU_HIDDEN=
     # true if syslinux supports TEXT HELP directive
     FEATURE_SYSLINUX_TEXT_HELP=
-        # true if syslinux supports modules sub-dir (Version > 5.00)
-        FEATURE_SYSLINUX_MODULES=
-    # If ISO_DEFAULT is not set, set it to default 'boothd'
-    if [ -z "$ISO_DEFAULT" ]; then
-        ISO_DEFAULT="boothd"
-    fi
+    # true if syslinux supports modules sub-dir (Version > 5.00)
+    FEATURE_SYSLINUX_MODULES=
+    # If ISO_DEFAULT is not set or empty or only blanks, set it to default 'boothd'
+    test $ISO_DEFAULT || ISO_DEFAULT="boothd"
     # Define the syslinux directory for later usage (since version 5 the bins and c32 are in separate dirs)
     if [[ -z "$SYSLINUX_DIR" ]]; then
         ISOLINUX_BIN=$(find_syslinux_file isolinux.bin)
@@ -261,9 +259,9 @@ function make_syslinux_config {
     echo "kernel kernel"
     echo "append initrd=$REAR_INITRD_FILENAME root=/dev/ram0 vga=normal rw $KERNEL_CMDLINE"
     if [ "$ISO_DEFAULT" == "manual" ] ; then
-               echo "default rear"
-               syslinux_menu "default"
-        fi
+        echo "default rear"
+        syslinux_menu "default"
+    fi
     echo ""
 
     echo "say rear - Recover $HOSTNAME"
@@ -275,10 +273,10 @@ function make_syslinux_config {
     echo "append initrd=$REAR_INITRD_FILENAME root=/dev/ram0 vga=normal rw $KERNEL_CMDLINE auto_recover $ISO_RECOVER_MODE"
 
     if [ "$ISO_DEFAULT" == "automatic" ] ; then
-               echo "default rear-automatic"
-               syslinux_menu "default"
-               echo "timeout 50"
-        fi
+        echo "default rear-automatic"
+        syslinux_menu "default"
+        echo "timeout 50"
+    fi
     echo ""
 
     syslinux_menu separator
@@ -306,6 +304,11 @@ function make_syslinux_config {
             echo "default boothd0"
             syslinux_menu "default"
         fi
+        if test "boothd0" = "$ISO_DEFAULT" ; then
+            # the user has explicitly specified to boot via boothd0 by default
+            echo "default boothd0"
+            syslinux_menu "default"
+        fi
         echo "kernel chain.c32"
         echo "append hd0"
         echo ""
@@ -319,6 +322,11 @@ function make_syslinux_config {
             echo "default boothd1"
             syslinux_menu "default"
         fi
+        if test "boothd1" = "$ISO_DEFAULT" ; then
+            # the user has explicitly specified to boot via boothd1 by default
+            echo "default boothd1"
+            syslinux_menu "default"
+        fi
         echo "kernel chain.c32"
         echo "append hd1"
         echo ""

usr/share/rear/output/USB/Linux-i386/300_create_extlinux.sh

@@ -214,7 +214,7 @@ EOF
 menu begin $system
     menu label $system
     text help
-Recover backup of $system to this system.
+Recover backup of $system to this system
     endtext
 
 EOF
@@ -341,34 +341,78 @@ EOF
 label help
     menu label ^Help for Relax-and-Recover
     text help
-More information about Relax-and-Recover and the steps for recovering your system
+Information about Relax-and-Recover and steps for recovering your system
     endtext
     menu help rear.help
 
 EOF
     fi
 
     # Use chain booting for booting disk, if chain.c32 is available
-    if syslinux_has "chain.c32"; then
-        syslinux_write <<EOF
+    if syslinux_has "chain.c32" ; then
+        # Boot from boothd0 (which is usually the same USB disk where this syslinux boot menue is currently shown)
+        # only as boot default when that was explicitly specified by the user (results usually a boot loop):
+        if test "boothd0" = "$USB_BIOS_BOOT_DEFAULT" ; then
+            syslinux_write <<EOF
+ontimeout boothd0
+label boothd0
+    say boothd0 - boot first local disk
+    menu label Boot ^First local disk (hd0)
+    text help
+Usually hd0 is the USB disk wherefrom currently is booted
+    endtext
+    menu default
+    kernel chain.c32
+    append hd0
+
+label boothd1
+    say boothd1 - boot second local disk
+    menu label Boot ^Second local disk (hd1)
+    text help
+Usually hd1 is the local harddisk
+    endtext
+    kernel chain.c32
+    append hd1
+
+EOF
+        else
+            # Boot from boothd1 (which is usually the local harddisk) by default (i.e. when USB_BIOS_BOOT_DEFAULT is not boothd0):
+            syslinux_write <<EOF
+label boothd0
+    say boothd0 - boot first local disk
+    menu label Boot ^First local disk (hd0)
+    text help
+Usually hd0 is the USB disk wherefrom currently is booted
+    endtext
+    kernel chain.c32
+    append hd0
+
 ontimeout boothd1
 label boothd1
     say boothd1 - boot second local disk
-    menu label Boot ^Local disk (hd1)
+    menu label Boot ^Second local disk (hd1)
+    text help
+Usually hd1 is the local harddisk
+    endtext
     menu default
     kernel chain.c32
     append hd1
 
+EOF
+        fi
+
+        syslinux_write <<EOF
 label bootlocal
     say bootlocal - boot second local bios disk
     menu label Boot ^BIOS disk (0x81)
     text help
-Use this when booting from local disk 0x81 does not work !
+Try this when booting from local disk does not work
     endtext
     localboot 0x81
 
 EOF
     else
+        # Fallback when chain.c32 is not available:
         syslinux_write <<EOF
 ontimeout bootlocal
 label bootlocal
@@ -383,7 +427,7 @@ EOF
 label bootnext
     menu label Boot ^Next device
     text help
-Boot from the next device in the BIOS boot order list.
+Boot from the next device in the BIOS boot order list
     endtext
     localboot -1