commit 42e04f36f5f8eea0017915bb35e56ee285b394d7
Merge: 7c6296db 940fede7
Author: Johannes Meixner <jsmeix@suse.com>
Date: Tue Jan 31 13:13:56 2023 +0100
Merge pull request #2915 from rear/jsmeix-serial-devs-fail-safe
In lib/serial-functions.sh make the
get_serial_console_devices() function
fail-safe if no serial device node exists, see
https://github.com/rear/rear/issues/2914
diff --git a/usr/share/rear/lib/serial-functions.sh b/usr/share/rear/lib/serial-functions.sh
index aac5dc88..3d421b52 100644
--- a/usr/share/rear/lib/serial-functions.sh
+++ b/usr/share/rear/lib/serial-functions.sh
@@ -1,13 +1,24 @@
# Get available serial devices:
function get_serial_console_devices () {
- test "$SERIAL_CONSOLE_DEVICES" && echo $SERIAL_CONSOLE_DEVICES || ls /dev/ttyS[0-9]* /dev/hvsi[0-9]* | sort
+ # Via SERIAL_CONSOLE_DEVICES the user specifies which ones to use (and no others):
+ if test "$SERIAL_CONSOLE_DEVICES" ; then
+ echo $SERIAL_CONSOLE_DEVICES
+ return 0
+ fi
+ # Test if there is /dev/ttyS[0-9]* or /dev/hvsi[0-9]*
+ # because when there is neither /dev/ttyS[0-9]* nor /dev/hvsi[0-9]*
+ # the ls command below would become plain 'ls' because of 'nullglob'
+ # cf. "Beware of the emptiness" in https://github.com/rear/rear/wiki/Coding-Style
+ # see https://github.com/rear/rear/issues/2914#issuecomment-1396659184
+ # and return 0 because it is no error when no serial device node exists
+ test "$( echo -n /dev/ttyS[0-9]* /dev/hvsi[0-9]* )" || return 0
# Use plain 'sort' which results /dev/ttyS0 /dev/ttyS1 /dev/ttyS10 ... /dev/ttyS19 /dev/ttyS2 /dev/ttyS20 ...
# to get at least /dev/ttyS0 and /dev/ttyS1 before the other /dev/ttyS* devices because
# we cannot use "sort -V" which would result /dev/ttyS0 /dev/ttyS1 ... /dev/ttyS9 /dev/ttyS10 ...
# because in older Linux distributions 'sort' does not support '-V' e.g. SLES10 with GNU coreutils 5.93
# (SLES11 with GNU coreutils 8.12 supports 'sort -V') but if 'sort' fails there is no output at all
- # cf. "Maintain backward compatibility" at https://github.com/rear/rear/wiki/Coding-Style
+ # cf. "Maintain backward compatibility" in https://github.com/rear/rear/wiki/Coding-Style
# Furthermore 'sort' results that /dev/hvsi* devices appear before /dev/ttyS* devices
# so the create_grub2_serial_entry function in lib/bootloader-functions.sh
# which uses by default the first one and skips the rest will result that
@@ -16,7 +27,8 @@ function get_serial_console_devices () {
# that have the HVSI driver loaded (a console driver for IBM's p5 servers)
# cf. https://lwn.net/Articles/98442/
# and it seems right that when special console drivers are loaded
- # then their devices should be preferred by default.
+ # then their devices should be preferred by default:
+ ls /dev/ttyS[0-9]* /dev/hvsi[0-9]* | sort
}
# Get the serial device speed for those device nodes that belong to actual serial devices.
commit 07da02143b5597b202e66c187e53103561018255
Merge: 91942f63 75a23e79
Author: Johannes Meixner <jsmeix@suse.com>
Date: Fri Oct 20 14:45:23 2023 +0200
Merge pull request #2961 from rear/jsmeix-copy-serial-console
For the automated serial console setup for the recovery system
use only the 'console=...' kernel arguments from the original system
which fixes https://github.com/rear/rear/issues/2843
and it means that no longer all "real serial devices" get
auto-enabled as serial consoles in the recovery system, see
https://github.com/rear/rear/pull/2749#issuecomment-1196650631
That new default behaviour is described in default.conf.
In particular prep/GNU/Linux/200_include_serial_console.sh
and lib/serial-functions.sh were overhauled which results
that rescue/GNU/Linux/400_use_serial_console.sh is obsolete.
Cherry-picked-by: Lukáš Zaoral <lzaoral@redhat.com>
diff --git a/usr/share/rear/conf/default.conf b/usr/share/rear/conf/default.conf
index ec1691b6..76355fb8 100644
--- a/usr/share/rear/conf/default.conf
+++ b/usr/share/rear/conf/default.conf
@@ -3320,39 +3320,90 @@ SIMPLIFY_TEAMING=no
SIMPLIFY_TEAMING=no
# Serial console support for the ReaR rescue/recovery system:
-# By default serial consoles get enabled if serial devices are found and
-# then matching kernel command line parameters like 'console=ttyS0,9600 console=ttyS1,9600'
-# are set when booting the rescue/recovery system (see KERNEL_CMDLINE above).
# IA64 platforms require it and people need it when no VGA console is available.
-# Specify 'yes' or 'no' or leave it empty to use ReaR's automatism:
+# By default there is serial console support in the ReaR recovery system
+# when 'getty' or 'agetty' and 'stty' can be found,
+# otherwise USE_SERIAL_CONSOLE is automatically set to 'no'.
+# When 'getty' or 'agetty' and 'stty' can be found
+# and there is a 'console=...' option in /proc/cmdline,
+# then USE_SERIAL_CONSOLE is automatically set to 'yes'.
+# With USE_SERIAL_CONSOLE="no" no serial console gets set up,
+# neither for the recovery system kernel nor for the recovery system bootloader.
+# With USE_SERIAL_CONSOLE="yes" plus appropriate SERIAL_CONSOLE_DEVICE... settings
+# serial consoles can be specified for the recovery system kernel and bootloader
+# for example when there is no 'console=...' option in /proc/cmdline
+# or when serial consoles for the recovery system kernel and bootloader
+# should differ from what 'console=...' options in /proc/cmdline tell.
+# By default (when empty) the automatism further described below is used:
USE_SERIAL_CONSOLE=
-# If you do not want to use all serial devices found as console you can specify the ones to use
-# e.g. SERIAL_CONSOLE_DEVICES="/dev/ttyS0 /dev/ttyS1" provided USE_SERIAL_CONSOLE is turned on.
-# By default (when empty) all serial devices found are used:
+#
+# Devices to be used in general for serial console setup
+# unless explicitly specified via SERIAL_CONSOLE_DEVICES_KERNEL
+# or SERIAL_CONSOLE_DEVICE_SYSLINUX or SERIAL_CONSOLE_DEVICE_GRUB:
+# E.g. SERIAL_CONSOLE_DEVICES="/dev/ttyS0 /dev/ttyS1"
SERIAL_CONSOLE_DEVICES=
-# Serial consoles for the kernel of the recovery system:
+#
+# Serial consoles for the kernel of the recovery system
+# provided USE_SERIAL_CONSOLE is not 'no':
# SERIAL_CONSOLE_DEVICES_KERNEL can be device nodes like "/dev/ttyS0 /dev/ttyS1"
# or 'console=...' kernel parameters like "console=ttyS1,9600 console=tty0" or both like
# SERIAL_CONSOLE_DEVICES_KERNEL="/dev/ttyS0 console=ttyS1,9600 console=tty0"
-# provided USE_SERIAL_CONSOLE is turned on.
-# By default (when empty) the SERIAL_CONSOLE_DEVICES are used for the kernel:
+# When SERIAL_CONSOLE_DEVICES_KERNEL is empty but SERIAL_CONSOLE_DEVICES is specified
+# then the specified SERIAL_CONSOLE_DEVICES are used for the kernel.
+# By default (when SERIAL_CONSOLE_DEVICES_KERNEL and SERIAL_CONSOLE_DEVICES are empty)
+# serial consoles get enabled for the recovery system kernel via COPY_KERNEL_PARAMETERS
+# for all 'console=...' options that are found in /proc/cmdline.
SERIAL_CONSOLE_DEVICES_KERNEL=
-# Serial console for SYSLINUX/EXTLINUX when it is used as bootloader for the recovery system:
+#
+# Serial console for SYSLINUX/EXTLINUX when it is used as bootloader for the recovery system
+# provided USE_SERIAL_CONSOLE is 'yes' (automatically with 'console=...' in /proc/cmdline):
# SYSLINUX supports only one serial device (because the last SYSLINUX 'serial' directive wins).
# The right /dev/ttyS* can be specified like SERIAL_CONSOLE_DEVICE_SYSLINUX="/dev/ttyS0"
# or a whole SYSLINUX 'serial' directive can be specified e.g. for /dev/ttyS1 like
# SERIAL_CONSOLE_DEVICE_SYSLINUX="serial 1 9600"
-# provided USE_SERIAL_CONSOLE is turned on.
-# By default (when empty) the first one of SERIAL_CONSOLE_DEVICES is used for SYSLINUX:
+# When SERIAL_CONSOLE_DEVICE_SYSLINUX is empty but SERIAL_CONSOLE_DEVICES is specified
+# then the first one of SERIAL_CONSOLE_DEVICES is used for SYSLINUX.
+# By default (when SERIAL_CONSOLE_DEVICE_SYSLINUX and SERIAL_CONSOLE_DEVICES are empty)
+# the devices of the 'console=...' options in /proc/cmdline
+# that exist as /dev/ttyS* or /dev/hvsi* character device nodes are used
+# (which excludes /dev/tty0 when there is 'console=tty0' in /proc/cmdline).
SERIAL_CONSOLE_DEVICE_SYSLINUX=
-# Serial console for GRUB when it is used as bootloader for the recovery system:
+#
+# Serial console for GRUB when it is used as bootloader for the recovery system
+# provided USE_SERIAL_CONSOLE is 'yes' (automatically with 'console=...' in /proc/cmdline):
# GRUB supports only one serial device (because the last GRUB 'serial' command wins).
# The right /dev/ttyS* can be specified like SERIAL_CONSOLE_DEVICE_GRUB="/dev/ttyS0"
# or a whole GRUB 'serial' command can be specified e.g. for /dev/ttyS1 like
# SERIAL_CONSOLE_DEVICE_GRUB="serial --unit=1 --speed=9600"
-# provided USE_SERIAL_CONSOLE is turned on.
-# By default (when empty) the first one of SERIAL_CONSOLE_DEVICES is used for GRUB:
+# When SERIAL_CONSOLE_DEVICE_GRUB is empty but SERIAL_CONSOLE_DEVICES is specified
+# then the first one of SERIAL_CONSOLE_DEVICES is used for GRUB.
+# By default (when SERIAL_CONSOLE_DEVICE_GRUB and SERIAL_CONSOLE_DEVICES are empty)
+# the devices of the 'console=...' options in /proc/cmdline
+# that exist as /dev/ttyS* or /dev/hvsi* character device nodes are used
+# (which excludes /dev/tty0 when there is 'console=tty0' in /proc/cmdline).
SERIAL_CONSOLE_DEVICE_GRUB=
+#
+# Examples
+# (provided USE_SERIAL_CONSOLE is not 'no'
+# and 'getty' or 'agetty' and 'stty' can be found):
+#
+# Default behaviour
+# when there is no 'console=...' option in /proc/cmdline
+# then no serial console is set up for the recovery system.
+#
+# Default behaviour when there are for example
+# 'console=ttyS0,9600' and 'console=tty0' in /proc/cmdline
+# then 'console=ttyS0,9600' and 'console=tty0'
+# are used for the recovery system kernel
+# and only /dev/ttyS0 is used as serial console
+# for the recovery system bootloader (SYSLINUX or GRUB).
+#
+# On a headless machine without VGA card but with serial device /dev/ttyS0
+# the kernel would choose /dev/ttyS0 as its console automatically
+# so no 'console=...' kernel option needs to be used and then the automatism described above
+# would not set up a console for the recovery system (in particular not for the bootloader).
+# In this case USE_SERIAL_CONSOLE="yes" and appropriate SERIAL_CONSOLE_DEVICE... settings
+# are needed to manually specify the right console setup for the recovery system.
# Say "y", "Yes", etc, to enable or "n", "No" etc. to disable the DHCP client protocol or leave empty to autodetect.
# When enabled, lets the rescue/recovery system run dhclient to get an IP address
# instead of using the same IP address as the original system:
diff --git a/usr/share/rear/lib/serial-functions.sh b/usr/share/rear/lib/serial-functions.sh
index 3d421b52..a586d357 100644
--- a/usr/share/rear/lib/serial-functions.sh
+++ b/usr/share/rear/lib/serial-functions.sh
@@ -6,29 +6,34 @@ function get_serial_console_devices () {
echo $SERIAL_CONSOLE_DEVICES
return 0
fi
- # Test if there is /dev/ttyS[0-9]* or /dev/hvsi[0-9]*
- # because when there is neither /dev/ttyS[0-9]* nor /dev/hvsi[0-9]*
- # the ls command below would become plain 'ls' because of 'nullglob'
- # cf. "Beware of the emptiness" in https://github.com/rear/rear/wiki/Coding-Style
- # see https://github.com/rear/rear/issues/2914#issuecomment-1396659184
- # and return 0 because it is no error when no serial device node exists
- test "$( echo -n /dev/ttyS[0-9]* /dev/hvsi[0-9]* )" || return 0
- # Use plain 'sort' which results /dev/ttyS0 /dev/ttyS1 /dev/ttyS10 ... /dev/ttyS19 /dev/ttyS2 /dev/ttyS20 ...
- # to get at least /dev/ttyS0 and /dev/ttyS1 before the other /dev/ttyS* devices because
- # we cannot use "sort -V" which would result /dev/ttyS0 /dev/ttyS1 ... /dev/ttyS9 /dev/ttyS10 ...
- # because in older Linux distributions 'sort' does not support '-V' e.g. SLES10 with GNU coreutils 5.93
- # (SLES11 with GNU coreutils 8.12 supports 'sort -V') but if 'sort' fails there is no output at all
- # cf. "Maintain backward compatibility" in https://github.com/rear/rear/wiki/Coding-Style
- # Furthermore 'sort' results that /dev/hvsi* devices appear before /dev/ttyS* devices
- # so the create_grub2_serial_entry function in lib/bootloader-functions.sh
- # which uses by default the first one and skips the rest will result that
- # the first /dev/hvsi* device becomes used for the GRUB serial console by default
- # which looks right because /dev/hvsi* devices should exist only on systems
- # that have the HVSI driver loaded (a console driver for IBM's p5 servers)
- # cf. https://lwn.net/Articles/98442/
- # and it seems right that when special console drivers are loaded
- # then their devices should be preferred by default:
- ls /dev/ttyS[0-9]* /dev/hvsi[0-9]* | sort
+ # Scan the kernel command line of the currently running original system
+ # for 'console=<device>[,<options>]' settings e.g. 'console=ttyS1,9600n8 ... console=ttyS3 ... console=tty0'
+ # and extract the specified serial device nodes e.g. ttyS1 -> /dev/ttyS1 ... ttyS3 -> /dev/ttyS3
+ local kernel_option console_option_value console_option_device
+ for kernel_option in $( cat /proc/cmdline ) ; do
+ # Continue with next kernel option when the option name (part before leftmost "=") is not 'console':
+ test "${kernel_option%%=*}" = "console" || continue
+ # Get the console option value (part after leftmost "=") e.g. 'ttyS1,9600n8' 'ttyS3' 'tty0'
+ console_option_value="${kernel_option#*=}"
+ # Get the console option device (part before leftmost optional ',' separator) e.g. 'ttyS1' 'ttyS3' 'tty0'
+ console_option_device="${console_option_value%%,*}"
+ # Continue with next kernel option when the current console option device is no serial device (exclude 'tty0').
+ # The special /dev/hvsi* devices should exist only on systems that have the HVSI driver loaded
+ # (a console driver for IBM's p5 servers) cf. https://lwn.net/Articles/98442/
+ [[ $console_option_device == ttyS* ]] || [[ $console_option_device == hvsi* ]] || continue
+ # Test that the matching serial device node e.g. ttyS1 -> /dev/ttyS1 and ttyS3 -> /dev/ttyS3' exists
+ # to avoid that this automated serial console setup may not work in the ReaR recovery system
+ # when serial device nodes get specified for the recovery system that do not exist
+ # in the currently running original system because the default assumption is
+ # that the replacement system has same hardware as the original system,
+ # cf. https://github.com/rear/rear/pull/2749#issuecomment-1196650631
+ # (if needed the user can specify what he wants via SERIAL_CONSOLE_DEVICES, see above):
+ if ! test -c "/dev/$console_option_device" ; then
+ LogPrintError "Found '$kernel_option' in /proc/cmdline but '/dev/$console_option_device' is no character device"
+ continue
+ fi
+ echo /dev/$console_option_device
+ done
}
# Get the serial device speed for those device nodes that belong to actual serial devices.
@@ -39,64 +44,15 @@ function get_serial_device_speed () {
# Run it in a subshell so that 'set -o pipefail' does not affect the current shell and
# it can run in a subshell because the caller of this function only needs its stdout
# cf. the function get_root_disk_UUID in lib/bootloader-functions.sh
- # so when stty fails the get_serial_device_speed return code is the stty exit code and not the awk exit code
- # therefore one can call get_serial_device_speed with error checking for example like
+ # so when stty fails the get_serial_device_speed return code is the stty exit code and not the awk exit code.
+ # Therefore one can call get_serial_device_speed with error checking for example like
# speed=$( get_serial_device_speed $serial_device ) && COMMAND_WITH_speed || COMMAND_WITHOUT_speed
- # because the return code of variable=$( PIPE ) is the return code of the pipe,
- # cf. how get_serial_device_speed is called in cmdline_add_console below.
+ # because the return code of variable=$( PIPE ) is the return code of the pipe
+ # cf. how get_serial_device_speed is called in lib/bootloader-functions.sh
+ # and output/USB/Linux-i386/300_create_extlinux.sh
# Suppress stty stderr output because for most /dev/ttyS* device nodes the result is
# stty: /dev/ttyS...: Input/output error
# when the device node does not belong to an actual serial device (i.e. to real serial hardware)
# so get_serial_device_speed is also used to get those device nodes that belong to real serial devices:
( set -o pipefail ; stty -F $devnode 2>/dev/null | awk '/^speed / { print $2 }' )
}
-
-# Add serial console to kernel cmdline:
-function cmdline_add_console {
- # Nothing to do when using serial console is not wanted:
- is_true "$USE_SERIAL_CONSOLE" || return 0
-
- # Strip existing 'console=...' kernel cmd parameters:
- local param cmdline=""
- for param in $KERNEL_CMDLINE ; do
- case "$param" in
- (console=*) ;;
- (*) cmdline+=" $param";;
- esac
- done
-
- # Add serial console config to kernel cmd line:
- local devnode speed=""
- if test "$SERIAL_CONSOLE_DEVICES_KERNEL" ; then
- # When the user has specified SERIAL_CONSOLE_DEVICES_KERNEL use only that (no automatisms):
- for devnode in $SERIAL_CONSOLE_DEVICES_KERNEL ; do
- # devnode can be a character device node like "/dev/ttyS0" or "/dev/lp0" or "/dev/ttyUSB0"
- # cf. https://www.kernel.org/doc/html/latest/admin-guide/serial-console.html
- # or devnode can be a 'console=...' kernel cmd parameter like "console=ttyS1,9600"
- if test -c "$devnode" ; then
- if speed=$( get_serial_device_speed $devnode ) ; then
- cmdline+=" console=${devnode##/dev/},$speed"
- else
- cmdline+=" console=${devnode##/dev/}"
- fi
- else
- # When devnode is a 'console=...' kernel cmd parameter use it as specified:
- cmdline+=" $devnode"
- fi
- done
- else
- local real_consoles=""
- for devnode in $( get_serial_console_devices ) ; do
- # Only add for those device nodes that belong to actual serial devices:
- speed=$( get_serial_device_speed $devnode ) && real_consoles+=" console=${devnode##/dev/},$speed"
- done
- cmdline+=" $real_consoles"
-
- # Add fallback console if no real serial device was found:
- test "$real_consoles" || cmdline+=" console=tty0"
- fi
-
- # Have a trailing space to be on the safe side
- # so that more kernel cmd parameters could be "just appended" by other scripts:
- echo "$cmdline "
-}
diff --git a/usr/share/rear/prep/GNU/Linux/200_include_serial_console.sh b/usr/share/rear/prep/GNU/Linux/200_include_serial_console.sh
index 214af3c4..14ec113e 100644
--- a/usr/share/rear/prep/GNU/Linux/200_include_serial_console.sh
+++ b/usr/share/rear/prep/GNU/Linux/200_include_serial_console.sh
@@ -1,31 +1,115 @@
-# If possible auto-enable serial console when not specified:
-if [[ -z "$USE_SERIAL_CONSOLE" ]] ; then
- local devnode speed=""
- for devnode in $( get_serial_console_devices ) ; do
- # Enable serial console when there is at least one real serial device:
- if speed=$( get_serial_device_speed $devnode ) ; then
- USE_SERIAL_CONSOLE="yes"
- break
- fi
- done
-fi
+# This script prep/GNU/Linux/200_include_serial_console.sh
+# is the first ...console... script that is run for "rear mkrescue/mkbackup".
+#
+# When USE_SERIAL_CONSOLE is empty then this script decides
+# if USE_SERIAL_CONSOLE is kept empty
+# or (provided there is sufficient reason)
+# it sets USE_SERIAL_CONSOLE to 'no' or 'yes'.
+# It sets USE_SERIAL_CONSOLE to 'no'
+# when serial consoles cannot work in the recovery system.
+# It sets USE_SERIAL_CONSOLE to 'yes'
+# when a serial console will be set up for the recovery system kernel.
+# Only when a serial console will be actually set up for the recovery system kernel,
+# then it makes sense to also set up a serial console for the recovery system bootloader.
+# So serial console setup for the recovery system bootloader is only done if USE_SERIAL_CONSOLE="yes"
+# because an empty USE_SERIAL_CONSOLE must not result serial console setup for the recovery system bootloader
+# (without actual serial console setup for the recovery system kernel).
-# Always include getty or agetty as we don't know in advance whether they are needed
+# Always try to include getty or agetty as we do not know in advance whether they are needed
# (the user may boot the recovery system with manually specified kernel options
# to get serial console support in his recovery system).
-# For serial support we need to include the agetty binary,
-# but Debian distro's use getty instead of agetty:
-local getty_binary=""
+# For serial console support we need to include 'getty' or 'agetty'.
+# Debian distributions (in particular Ubuntu) use 'getty'.
+# Fedora, RHEL, SLES,... use 'agetty'.
if has_binary getty ; then
- # Debian, Ubuntu,...
- getty_binary="getty"
+ PROGS+=( getty )
elif has_binary agetty ; then
- # Fedora, RHEL, SLES,...
- getty_binary="agetty"
+ PROGS+=( agetty )
+else
+ is_true "$USE_SERIAL_CONSOLE" && Error "Failed to find 'getty' or 'agetty' (USE_SERIAL_CONSOLE is 'true')"
+ LogPrintError "No serial console support (failed to find 'getty' or 'agetty')"
+ USE_SERIAL_CONSOLE="no"
+fi
+
+# Also try to include 'stty' which is (currently) only needed for serial console support
+# in skel/default/etc/scripts/system-setup.d/45-serial-console.sh
+# and lib/serial-functions.sh
+if has_binary stty ; then
+ PROGS+=( stty )
else
- # The user must have the programs in REQUIRED_PROGS installed on his system:
- Error "Failed to find 'getty' or 'agetty' for serial console"
+ is_true "$USE_SERIAL_CONSOLE" && Error "Failed to find 'stty' (USE_SERIAL_CONSOLE is 'true')"
+ LogPrintError "No serial console support (failed to find 'stty')"
+ USE_SERIAL_CONSOLE="no"
fi
-REQUIRED_PROGS+=( "$getty_binary" stty )
+# Auto-enable serial console support for the recovery system
+# provided console support is not impossible because there is no getty or agetty and stty
+# and unless the user specified to not have serial console support:
+is_false "$USE_SERIAL_CONSOLE" && return 0
+
+# When the user has specified SERIAL_CONSOLE_DEVICES_KERNEL use only that,
+# otherwise use SERIAL_CONSOLE_DEVICES if the user has specified it:
+local serial_console_devices=""
+test "$SERIAL_CONSOLE_DEVICES" && serial_console_devices="$SERIAL_CONSOLE_DEVICES"
+test "$SERIAL_CONSOLE_DEVICES_KERNEL" && serial_console_devices="$SERIAL_CONSOLE_DEVICES_KERNEL"
+if test "$serial_console_devices" ; then
+ local serial_console speed="" cmdline_add_console=""
+ for serial_console in $serial_console_devices ; do
+ # serial_console can be a character device node like "/dev/ttyS0" or "/dev/lp0" or "/dev/ttyUSB0"
+ # cf. https://www.kernel.org/doc/html/latest/admin-guide/serial-console.html
+ # or serial_console can be a 'console=...' kernel cmd parameter like "console=ttyS1,9600"
+ if test -c "$serial_console" ; then
+ if speed=$( get_serial_device_speed $serial_console ) ; then
+ cmdline_add_console+=" console=${serial_console##/dev/},$speed"
+ else
+ cmdline_add_console+=" console=${serial_console##/dev/}"
+ fi
+ else
+ # When serial_console is not a character device
+ # it should be a 'console=...' kernel cmd parameter
+ # that is used as specified ("final power to the user"):
+ cmdline_add_console+=" $serial_console"
+ fi
+ done
+ if test "$cmdline_add_console" ; then
+ KERNEL_CMDLINE+="$cmdline_add_console"
+ DebugPrint "Appended '$cmdline_add_console' to KERNEL_CMDLINE"
+ USE_SERIAL_CONSOLE="yes"
+ # No further automatisms when a 'console=...' kernel cmd parameter was set
+ # via SERIAL_CONSOLE_DEVICES_KERNEL or SERIAL_CONSOLE_DEVICES:
+ return
+ fi
+ LogPrintError "SERIAL_CONSOLE_DEVICES_KERNEL or SERIAL_CONSOLE_DEVICES specified but none is a character device"
+fi
+
+# Auto-enable serial console support for the recovery system kernel:
+# The below auto-enable serial console support for the recovery system kernel
+# does not auto-enable serial console support for the recovery system bootloader.
+# Currently auto-enable serial console support for the recovery system bootloader
+# happens for the first real serial device from get_serial_console_devices()
+# in lib/bootloader-functions.sh in make_syslinux_config() and create_grub2_cfg()
+# and in output/USB/Linux-i386/300_create_extlinux.sh
+# The auto-enable serial console support for the recovery system bootloader should be
+# auto-aligned with the auto-enable serial console support for the recovery system kernel.
+# Things are auto-aligned when the first 'console=...' device in /proc/cmdline
+# is also the first real serial device from get_serial_console_devices().
+# When current auto-alignment does not result what the user needs, what is needed can be specified
+# via SERIAL_CONSOLE_DEVICES_KERNEL and SERIAL_CONSOLE_DEVICE_SYSLINUX or SERIAL_CONSOLE_DEVICE_GRUB.
+
+# Scan the kernel command line of the currently running original system
+# and auto-enable serial console for the recovery system kernel
+# only if there is at least one 'console=...' option:
+local kernel_option
+for kernel_option in $( cat /proc/cmdline ) ; do
+ # Get the kernel option name (part before leftmost "="):
+ if test "${kernel_option%%=*}" = "console" ; then
+ USE_SERIAL_CONSOLE="yes"
+ # Get all 'console=...' kernel command line options
+ # copied from the currently running original system
+ # via rescue/GNU/Linux/290_kernel_cmdline.sh that runs later:
+ COPY_KERNEL_PARAMETERS+=( console )
+ return
+ fi
+done
+DebugPrint "No 'console=...' setting for recovery system kernel (none in /proc/cmdline)"
diff --git a/usr/share/rear/rescue/GNU/Linux/400_use_serial_console.sh b/usr/share/rear/rescue/GNU/Linux/400_use_serial_console.sh
deleted file mode 100644
index fc935844..00000000
--- a/usr/share/rear/rescue/GNU/Linux/400_use_serial_console.sh
+++ /dev/null
@@ -1,6 +0,0 @@
-
-# Nothing to do when using serial console is not wanted:
-is_true "$USE_SERIAL_CONSOLE" || return 0
-
-KERNEL_CMDLINE=$( cmdline_add_console )
-Log "Modified kernel commandline to: '$KERNEL_CMDLINE'"