Libguestfs - Nov 2014 - Re: [PATCH] customize: firstboot: make sure to run Linux scripts only once

If a script does not finish, hangs, etc, it would be executed again at
the next boot, since the injected firstboot.sh helper removes it only
after it finished.

Since firstboot.sh only runs executable files, then remove the
executable attributes before running it, so it will not run again.
Also, remove any file found in the scripts subdirectory, be it just run
or run in a previous boot.

This fixes RHBZ#1159651.
---
 customize/firstboot.ml | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/customize/firstboot.ml b/customize/firstboot.ml
index 67b9479..5f68a2e 100644
--- a/customize/firstboot.ml
+++ b/customize/firstboot.ml
@@ -57,10 +57,13 @@ then
   for f in $d/* ; do
     if test -x \"$f\"
     then
+      # remove +x from the script being executed, so it is not
+      # executed again at the next boot
+      chmod -x $f
       echo '=== Running' $f '===' 2>&1 | tee $logfile
-      $f 2>&1 | tee $logfile
-      rm -f $f
+      sh $f 2>&1 | tee $logfile
     fi
+    rm -f $f
   done
 fi
 " firstboot_dir
-- 
1.9.3

On Mon, Nov 03, 2014 at 08:49:08PM +0100, Pino Toscano
wrote:
> If a script does not finish, hangs, etc, it would be executed again at
> the next boot, since the injected firstboot.sh helper removes it only
> after it finished.
> 
> Since firstboot.sh only runs executable files, then remove the
> executable attributes before running it, so it will not run again.
> Also, remove any file found in the scripts subdirectory, be it just run
> or run in a previous boot.
> 
> This fixes RHBZ#1159651.
> ---
>  customize/firstboot.ml | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/customize/firstboot.ml b/customize/firstboot.ml
> index 67b9479..5f68a2e 100644
> --- a/customize/firstboot.ml
> +++ b/customize/firstboot.ml
> @@ -57,10 +57,13 @@ then
>    for f in $d/* ; do
>      if test -x \"$f\"
>      then
> +      # remove +x from the script being executed, so it is not
> +      # executed again at the next boot
> +      chmod -x $f
>        echo '=== Running' $f '===' 2>&1 | tee
$logfile
> -      $f 2>&1 | tee $logfile
> -      rm -f $f
> +      sh $f 2>&1 | tee $logfile
I like the idea .. unfortunately I believe this will make it run the
wrong interpreter.  eg. If the firstboot script started with
'#!/usr/bin/perl' then this would run it with 'sh' instead.

I'm not sure how to work around that.  'env' maybe?

Is it better to document the problem instead?  Arguably this bug is
user error.  Perhaps they'd be better off doing something like:

  ( sleep 10 ; reboot ) &

at the end of their script.

Rich.
>      fi
> +    rm -f $f
>    done
>  fi
>  " firstboot_dir
> -- 
> 1.9.3
> 
> _______________________________________________
> Libguestfs mailing list
> Libguestfs@redhat.com
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-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org

If a script does not finish, hangs, etc, it would be executed again at
the next boot, since the injected firstboot.sh helper removes it only
after it finished.

Before executing a script, move it to another internal subdirectory
(scripts-done) and execute it from there, so it is not run again by
firstboot.sh.  The downside is that now scripts are executed only once
at all, so if a script fails it will not be attempted at the next boot.

Also, remove all the files found in scripts-done, as they have been run
(or at least attempted) in a previous boot.

This fixes RHBZ#1159651.
---
 customize/firstboot.ml | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/customize/firstboot.ml b/customize/firstboot.ml
index 67b9479..89821f3 100644
--- a/customize/firstboot.ml
+++ b/customize/firstboot.ml
@@ -47,6 +47,7 @@ module Linux = struct
 ### END INIT INFO
 
 d=%s/scripts
+d_done=%s/scripts-done
 logfile=~root/virt-sysprep-firstboot.log
 
 echo \"$0\" \"$@\" 2>&1 | tee $logfile
@@ -54,16 +55,20 @@ echo \"Scripts dir: $d\" 2>&1 | tee
$logfile
 
 if test \"$1\" = \"start\"
 then
+  mkdir -p $d_done
   for f in $d/* ; do
     if test -x \"$f\"
     then
+      # move the script to the 'scripts-done' directory, so it is not
+      # executed again at the next boot
+      mv $f $d_done
       echo '=== Running' $f '===' 2>&1 | tee $logfile
-      $f 2>&1 | tee $logfile
-      rm -f $f
+      $d_done/$(basename $f) 2>&1 | tee $logfile
     fi
   done
+  rm -f $d_done/*
 fi
-" firstboot_dir
+" firstboot_dir firstboot_dir
 
   let firstboot_service = sprintf "\
 [Unit]
-- 
1.9.3