Re: [PATCH v4] Let user specify the action after fail

[Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 03/29/2013 06:36 PM, Baoquan He wrote:
> Currently the default action is emergency_shell when failure happened
> during system boot. In kdump, this default may not be expected. E.g,
> if dump target is not rootfs, it does not matter if mount root failed.
> Adding an action which allow dracut always go ahead though failure
> happens is needed by kdump.
> 
> So here add a function action_on_fail() and cmdline parameter
> action_on_fail=<shell | continue>. Use action_to_fail() to replace
> emergency_shell which was called after failure. By $(getarg action_on_fail=),
> decide to drop into shell, or to leave away the failure and go ahead.
> 
> v3->v4:
> add handling of selinux policy loaded failure, and change code format to
> be consitent

There's still fsck error path to handle...

> 
> Signed-off-by: Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  dracut.cmdline.7.asc                      |    4 ++++
>  modules.d/95rootfs-block/mount-root.sh    |    7 ++++---
>  modules.d/98selinux/selinux-loadpolicy.sh |    6 ++----
>  modules.d/98systemd/dracut-initqueue.sh   |    2 +-
>  modules.d/98systemd/dracut-mount.sh       |    2 +-
>  modules.d/98usrmount/mount-usr.sh         |   14 ++++++++------
>  modules.d/99base/dracut-lib.sh            |   18 ++++++++++++++++++
>  modules.d/99base/init.sh                  |   12 ++++++------
>  8 files changed, 44 insertions(+), 21 deletions(-)
> 
> diff --git a/dracut.cmdline.7.asc b/dracut.cmdline.7.asc
> index f1457d5..e777715 100644
> --- a/dracut.cmdline.7.asc
> +++ b/dracut.cmdline.7.asc
> @@ -121,6 +121,10 @@ Misc
>     specify the controlling terminal for the console.
>     This is useful, if you have multiple "console=" arguments.
>  
> +**action_on_fail=**_{shell|continue}_::
> +   Specify the action after failure. By default it's emergency_shell.
> +   'continue' means leave away current failure and go ahead.
> +
>  [[dracutkerneldebug]]
>  Debug
>  ~~~~~
> diff --git a/modules.d/95rootfs-block/mount-root.sh b/modules.d/95rootfs-block/mount-root.sh
> index c7626c3..d020338 100755
> --- a/modules.d/95rootfs-block/mount-root.sh
> +++ b/modules.d/95rootfs-block/mount-root.sh
> @@ -66,9 +66,10 @@ mount_root() {
>              fi
>              if [ -n "$AUTOFSCK_SINGLEUSER" ]; then
>                  warn "*** Warning -- the system did not shut down cleanly. "
> -                warn "*** Dropping you to a shell; the system will continue"
> -                warn "*** when you leave the shell."
> -                emergency_shell
> +                warn "*** Dropping you to a shell by default; the system"
> +                warn "*** will continue when you leave the shell."
> +                warn "*** You can also spicify other actions."

It's not clear, better to print different content for different actions...

> +                action_on_fail
>              fi
>              fsckoptions="$AUTOFSCK_OPT $fsckoptions"
>          fi
> diff --git a/modules.d/98selinux/selinux-loadpolicy.sh b/modules.d/98selinux/selinux-loadpolicy.sh
> index d6e24d6..6f796b4 100755
> --- a/modules.d/98selinux/selinux-loadpolicy.sh
> +++ b/modules.d/98selinux/selinux-loadpolicy.sh
> @@ -52,16 +52,14 @@ rd_load_policy()
>          if [ $ret -eq 3 -o $permissive -eq 0 ]; then
>              warn "Machine in enforcing mode."
>              warn "Not continuing"
> -            emergency_shell -n selinux
> -            exit 1
> +            ! action_on_fail -n selinux && exit 1
>          fi
>          return 0
>      elif [ $permissive -eq 0 -a "$SELINUX" != "disabled" ]; then
>          warn "Machine in enforcing mode and cannot execute load_policy."
>          warn "To disable selinux, add selinux=0 to the kernel command line."
>          warn "Not continuing"
> -        emergency_shell -n selinux
> -        exit 1
> +        ! action_on_fail -n selinux && exit 1
>      fi
>  }
>  
> diff --git a/modules.d/98systemd/dracut-initqueue.sh b/modules.d/98systemd/dracut-initqueue.sh
> index c6fab30..2c71bf4 100755
> --- a/modules.d/98systemd/dracut-initqueue.sh
> +++ b/modules.d/98systemd/dracut-initqueue.sh
> @@ -62,7 +62,7 @@ while :; do
>      fi
>  
>      main_loop=$(($main_loop+1))
> -    [ $main_loop -gt $RDRETRY ] && emergency_shell "Could not boot."
> +    [ $main_loop -gt $RDRETRY ] && action_on_fail "Could not boot." && break
>  done
>  
>  unset job
> diff --git a/modules.d/98systemd/dracut-mount.sh b/modules.d/98systemd/dracut-mount.sh
> index 5f3d9f0..ae01512 100755
> --- a/modules.d/98systemd/dracut-mount.sh
> +++ b/modules.d/98systemd/dracut-mount.sh
> @@ -31,7 +31,7 @@ while :; do
>      done
>  
>      i=$(($i+1))
> -    [ $i -gt 20 ] && emergency_shell "Can't mount root filesystem"
> +    [ $i -gt 20 ] && action_on_fail "Can't mount root filesystem" && break
>  done
>  
>  export -p > /dracut-state.sh
> diff --git a/modules.d/98usrmount/mount-usr.sh b/modules.d/98usrmount/mount-usr.sh
> index 5aaefbc..823338b 100755
> --- a/modules.d/98usrmount/mount-usr.sh
> +++ b/modules.d/98usrmount/mount-usr.sh
> @@ -40,9 +40,10 @@ fsck_usr()
>          fi
>          if [ -n "$AUTOFSCK_SINGLEUSER" ]; then
>              warn "*** Warning -- the system did not shut down cleanly. "
> -            warn "*** Dropping you to a shell; the system will continue"
> -            warn "*** when you leave the shell."
> -            emergency_shell
> +            warn "*** Dropping you to a shell by default; the system"
> +            warn "*** will continue when you leave the shell."
> +            warn "*** You can also spicify other actions."
> +            action_on_fail
>          fi
>          _fsckoptions="$AUTOFSCK_OPT $_fsckoptions"
>      fi
> @@ -103,9 +104,10 @@ mount_usr()
>  
>          if ! ismounted "$NEWROOT/usr"; then
>              warn "Mounting /usr to $NEWROOT/usr failed"
> -            warn "*** Dropping you to a shell; the system will continue"
> -            warn "*** when you leave the shell."
> -            emergency_shell
> +            warn "*** Dropping you to a shell by default; the system"
> +            warn "*** will continue when you leave the shell."
> +            warn "*** You can also spicify other actions."
> +            action_on_fail
>          fi
>      fi
>  }
> diff --git a/modules.d/99base/dracut-lib.sh b/modules.d/99base/dracut-lib.sh
> index e456b01..8d1bf0a 100755
> --- a/modules.d/99base/dracut-lib.sh
> +++ b/modules.d/99base/dracut-lib.sh
> @@ -975,6 +975,24 @@ emergency_shell()
>      [ -e /run/initramfs/.die ] && exit 1
>  }
>  
> +action_on_fail()
> +{
> +    local _action=$(getarg action_on_fail=)
> +    case "$_action" in
> +        continue)

The arguments need to be handled here as well as emergency_shell, ie.
print the messages, so later we can know there's something wrong
happened but it just been ignored, thus we can check the log to fix the
root cause of the failure..

> +            return 0
> +            ;;
> +        shell)
> +            emergency_shell $@
> +            return 1
> +            ;;
> +        *)
> +            emergency_shell $@
> +            return 1
> +            ;;
> +    esac
> +}
> +
>  # Retain the values of these variables but ensure that they are unexported
>  # This is a POSIX-compliant equivalent of bash's "export -n"
>  export_n()
> diff --git a/modules.d/99base/init.sh b/modules.d/99base/init.sh
> index b441a27..64d7e3c 100755
> --- a/modules.d/99base/init.sh
> +++ b/modules.d/99base/init.sh
> @@ -79,7 +79,7 @@ if ! ismounted /run; then
>      rm -fr /newrun
>  fi
>  
> -trap "emergency_shell Signal caught!" 0
> +trap "action_on_fail Signal caught!" 0
>  
>  [ -d /run/initramfs ] || mkdir -p -m 0755 /run/initramfs
>  [ -d /run/log ] || mkdir -p -m 0755 /run/log
> @@ -199,7 +199,7 @@ while :; do
>  
>      main_loop=$(($main_loop+1))
>      [ $main_loop -gt $RDRETRY ] \
> -        && { flock -s 9 ; emergency_shell "Could not boot."; } 9>/.console_lock
> +        && { flock -s 9 ; action_on_fail "Could not boot." && break; } 9>/.console_lock
>  done
>  unset job
>  unset queuetriggered
> @@ -234,7 +234,7 @@ while :; do
>  
>      i=$(($i+1))
>      [ $i -gt 20 ] \
> -        && { flock -s 9 ; emergency_shell "Can't mount root filesystem"; } 9>/.console_lock
> +        && { flock -s 9 ; action_on_fail "Can't mount root filesystem" && break; } 9>/.console_lock
>  done
>  
>  {
> @@ -268,7 +268,7 @@ done
>  [ "$INIT" ] || {
>      echo "Cannot find init!"
>      echo "Please check to make sure you passed a valid root filesystem!"
> -    emergency_shell
> +    action_on_fail
>  }
>  
>  if [ $UDEVVERSION -lt 168 ]; then
> @@ -370,13 +370,13 @@ if [ -f /etc/capsdrop ]; then
>  	warn "Command:"
>  	warn capsh --drop=$CAPS_INIT_DROP -- -c exec switch_root "$NEWROOT" "$INIT" $initargs
>  	warn "failed."
> -	emergency_shell
> +	action_on_fail
>      }
>  else
>      unset RD_DEBUG
>      exec $SWITCH_ROOT "$NEWROOT" "$INIT" $initargs || {
>  	warn "Something went very badly wrong in the initramfs.  Please "
>  	warn "file a bug against dracut."
> -	emergency_shell
> +	action_on_fail
>      }
>  fi
> 


-- 
Thanks
Dave