Deprecate KCL in /etc/default/{zfsbootmenu,grub}

ZBM will complain when reading kernel command-line parameters from
/etc/default/{zfsbootmenu,grub} within a BE rather than from the ZFS
property org.zfsbootmenu:commandline. By default, the contents of these
files will be migrated to a ZFS property on the BE after the warning is
shown. This will happen once for each BE that provides a configuration
file and no property. The file /etc/default/zfsbootmenu will be removed
from the BE if that was the source for the KCL; /etc/default/grub is
never removed.

By pressing Esc, the user can ignore the deprecation warning without
attempting to migrate the KCL configuration. This allows ZBM to operate
as before. When the warning is ignored, ZBM will export an environment
variable and write to /etc/zfsbootmenu.conf in the initramfs to suppress
subsequent warnings until the next reboot.

Co-authored-by: Andrew J. Hesford <ajh@sideband.org>
Co-authored-by: Zach Dykstra <dykstra.zachary@gmail.com>

90zfsbootmenu/zfsbootmenu-lib.sh

@@ -1041,10 +1041,13 @@ find_be_kernels() {
         done
       done
     done
-
   done
 
+  # No further need for the mount
+  umount "${mnt}"
+
   defaults="$( select_kernel "${fs}" )"
+
   # shellcheck disable=SC2034
   IFS=' ' read -r def_fs def_kernel def_initramfs <<<"${defaults}"
 
@@ -1053,19 +1056,16 @@ find_be_kernels() {
   # If no default kernel is found, there are no kernels; leave the BE
   # directory in the same state it would be in had no /boot existed
   if [ -z "${def_kernel}" ]; then
-    umount "${mnt}"
     zdebug "no default kernel found for ${fs}"
     rm -f "${kernel_records}" "${def_kernel_file}"
     return 1
   fi
-  zdebug "default kernel set to ${def_kernel}"
 
+  zdebug "default kernel set to ${def_kernel}"
   echo "${def_kernel##*/}" > "${def_kernel_file}"
 
-  # Pre-load cmdline arguments, possibly from files on the mount
-  preload_be_cmdline "${fs}" "${mnt}"
-
-  umount "${mnt}"
+  # Pre-load cmdline arguments, possibly from files in the environment
+  preload_be_cmdline "${fs}"
   return 0
 }
 
@@ -1242,50 +1242,93 @@ read_kcl_prop() {
 }
 
 # arg1: ZFS filesystem
-# arg2: path for a mounted filesystem
 # prints: nothing
 # returns: 0 on success
 
 preload_be_cmdline() {
-  local zfsbe_mnt zfsbe_fs zfsbe_args args_file
-
-  zfsbe_fs="${1}"
-  if [ -z "${zfsbe_fs}" ]; then
-    zerror "zfsbe_fs is undefined"
-    return 1
-  fi
-  zdebug "zfsbe_fs set to ${zfsbe_fs}"
+  local fs mnt args args_file deprecated need_rw zsout
 
-  zfsbe_mnt="${2}"
-  if [ -z "${zfsbe_mnt}" ]; then
-    zerror "zfsbe_mnt is undefined"
+  fs="${1}"
+  if [ -z "${fs}" ]; then
+    zerror "fs is undefined"
     return 1
   fi
-  zdebug "zfsbe_mnt set to ${zfsbe_mnt}"
+  zdebug "fs set to ${fs}"
 
-  args_file="${BASE}/${zfsbe_fs}/cmdline"
+  args_file="${BASE}/${fs}/cmdline"
 
-  if zfsbe_args="$( read_kcl_prop "${zfsbe_fs}" )" && [ -n "${zfsbe_args}" ]; then
+  if args="$( read_kcl_prop "${fs}" )" && [ -n "${args}" ]; then
     zdebug "using org.zfsbootmenu:commandline"
-    echo "${zfsbe_args}" > "${args_file}"
-    return
+    echo "${args}" > "${args_file}"
+    return 0
   fi
 
-  if [ -n "${zfsbe_mnt}" ] && [ -r "${zfsbe_mnt}/etc/default/zfsbootmenu" ]; then
-    zdebug "using ${zfsbe_mnt}/etc/default/zfsbootmenu"
-    head -1 "${zfsbe_mnt}/etc/default/zfsbootmenu" | tr -d '\n' > "${args_file}"
-    return
+  # Mount R/O to check for config files
+  if ! mnt="$( mount_zfs "${fs}" )"; then
+    zerror "unable to mount ${fs}"
+    return 1
   fi
 
-  if [ -n "${zfsbe_mnt}" ] && [ -r "${zfsbe_mnt}/etc/default/grub" ]; then
-    zdebug "using ${zfsbe_mnt}/etc/default/grub"
+  if [ -r "${mnt}/etc/default/zfsbootmenu" ]; then
+    zdebug "using ${mnt}/etc/default/zfsbootmenu"
+    head -1 "${mnt}/etc/default/zfsbootmenu" | tr -d '\n' > "${args_file}"
+    deprecated="/etc/default/zfsbootmenu"
+  elif [ -r "${mnt}/etc/default/grub" ]; then
+    zdebug "using ${mnt}/etc/default/grub"
     echo "$(
       # shellcheck disable=SC1090,SC1091
-      . "${zfsbe_mnt}/etc/default/grub" ;
+      . "${mnt}/etc/default/grub" ;
       echo "${GRUB_CMDLINE_LINUX_DEFAULT}"
     )" > "${args_file}"
-    return
+    deprecated="/etc/default/grub"
   fi
+
+  # Always unmount, pool must be writable to perform migration
+  umount "${mnt}" || return 1
+
+  if [ "${deprecated}" = "/etc/default/zfsbootmenu" ]; then
+    # Need an R/W mount to remove deprecated config
+    need_rw="yes"
+  elif [ -z "${deprecated}" ] || [ -n "${zbm_ignore_kcl_deprecation}" ]; then
+    # Nothing is deprecated, so there is nothing to do
+    return 0
+  fi
+
+  # It is not an error if user declines automatic migration
+  if ! color=green delay=60 prompt="Will attempt migration in %0.2d seconds" \
+      timed_prompt "Using KCL from ${deprecated} on ${fs}" \
+      "This behavior is DEPRECATED and will be removed soon" "" \
+      "KCL should be migrated to an org.zfsbootmenu:commandline property" "" \
+      "[RETURN] to migrate" "[ESCAPE] to ignore "; then
+    # Suppress repeated messages
+    export zbm_ignore_kcl_deprecation=1
+    echo 'export zbm_ignore_kcl_deprecation="1"' >> /etc/zfsbootmenu.conf
+    return 0
+  fi
+
+  zdebug "migrating ${deprecated} to org.zfsbootmenu:commandline"
+
+  # Pool must be writable to set property and remove config
+  set_rw_pool "${fs%%/*}" || return 1
+  CLEAR_SCREEN=1 load_key "${fs}"
+
+  if ! mnt="$( allow_rw="${need_rw}" mount_zfs "${fs}" )"; then
+    zerror "unable to mount ${fs}"
+    return 1
+  fi
+
+  read -r args < "${args_file}"
+
+  if ! zsout="$( zfs set org.zfsbootmenu:commandline="${args}" "${fs}" 2>&1 )"; then
+    zerror "Unable to migrate ${deprecated} to org.zfsbootmenu:commandline: ${zsout}"
+  elif [ "${deprecated}" = "/etc/default/zfsbootmenu" ] ; then
+    zdebug "removing ${deprecated} from ${fs}"
+    rm "${mnt}${deprecated}" >/dev/null 2>&1
+  else
+    zdebug "not removing ${deprecated} from ${fs}"
+  fi
+
+  umount "${mnt}"
 }
 
 # arg1: key(and associated value) to suppress from KCL
@@ -1560,7 +1603,7 @@ timed_prompt() {
 
   [ $# -gt 0 ] || return
   [ -n "${delay}" ] || delay="30"
-  [ -n "${prompt}" ] || prompt="Press [RETURN] or wait %0.2d seconds to continue"
+  [ -n "${prompt}" ] || prompt="Press [RETURN] or wait %0.${#delay}d seconds to continue"
 
   [ "${delay}" -eq 0 ] && return
 

90zfsbootmenu/zfsbootmenu-preinit.sh

@@ -23,7 +23,7 @@ mkdir -p "${BASE}"
 
 # shellcheck disable=SC2154
 cat >> "/etc/zfsbootmenu.conf" <<EOF
-# Added by zfsbootmenu-preinit.sh
+# BEGIN additions by zfsbootmenu-preinit.sh
 export BASE="/zfsbootmenu"
 export endian="${endian}"
 export spl_hostid="${spl_hostid}"
@@ -37,6 +37,7 @@ export zbm_sort="${zbm_sort}"
 export zbm_set_hostid="${zbm_set_hostid}"
 export zbm_import_delay="${zbm_import_delay}"
 export control_term="${control_term}"
+# END additions by zfsbootmenu-preinit.sh
 EOF
 
 getcmdline > "${BASE}/zbm.cmdline"