diff mbox

scripts: update (rewrite) qemu-binfmt-conf.h

Message ID 1433014102-19878-1-git-send-email-laurent@vivier.eu
State New
Headers show

Commit Message

Laurent Vivier May 30, 2015, 7:28 p.m. UTC 
Orginal qemu-binfmt-conf.h is only able to write configuration
into /proc/sys/fs/binfmt_misc, and the configuration is lost on reboot.

This script can configure debian and systemd services to restore
configuration on reboot. Moreover, it is able to manage binfmt
credential and to configure the path of the interpreter.

Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian [--exportdir PATH]]
                           [--help][--credential yes|no][--systemd CPU]

       Configure binfmt_misc to use qemu interpreter

       --help:       display this usage
       --qemu-path:  set path to qemu interpreter
       --debian:     don't write into /proc,
                     instead generate update-binfmts templates
       --systemd:    don't write into /proc,
                     instead generate file for systemd-binfmt.service
                     for the given CPU
       --exportdir:  define where to write update-binfmts templates
       --credential: if yes, credential an security tokens are
                     calculated according to the binary to interpret

    To import templates with update-binfmts, use :

        sudo update-binfmts --importdir $EXPORTDIR --import qemu-CPU

    To remove interpreter, use :

        sudo update-binfmts --package qemu-CPU --remove qemu-CPU $QEMU_PATH

    With systemd, binfmt files are loaded by systemd-binfmt.service

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 scripts/qemu-binfmt-conf.sh | 366 +++++++++++++++++++++++++++++++++++---------
 1 file changed, 297 insertions(+), 69 deletions(-)
 mode change 100644 => 100755 scripts/qemu-binfmt-conf.sh

Comments

Peter Maydell May 30, 2015, 7:32 p.m. UTC | #1 
On 30 May 2015 at 20:28, Laurent Vivier <laurent@vivier.eu> wrote:
> Orginal qemu-binfmt-conf.h is only able to write configuration
> into /proc/sys/fs/binfmt_misc, and the configuration is lost on reboot.
>
> This script can configure debian and systemd services to restore
> configuration on reboot. Moreover, it is able to manage binfmt
> credential and to configure the path of the interpreter.


> +i386_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00'
> +i386_mask='\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
> +i386_family=i386

Personally I think it would be nice to store these in
update-binfmts(8) style format files rather than directly
in the script. That way we separate data from the
implementation, and it's convenient if you want to do
something else with the data than what the script does.

-- PMM
Laurent Vivier May 30, 2015, 7:51 p.m. UTC | #2 
Le 30/05/2015 21:32, Peter Maydell a écrit :
> On 30 May 2015 at 20:28, Laurent Vivier <laurent@vivier.eu> wrote:
>> Orginal qemu-binfmt-conf.h is only able to write configuration
>> into /proc/sys/fs/binfmt_misc, and the configuration is lost on reboot.
>>
>> This script can configure debian and systemd services to restore
>> configuration on reboot. Moreover, it is able to manage binfmt
>> credential and to configure the path of the interpreter.
> 
> 
>> +i386_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00'
>> +i386_mask='\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
>> +i386_family=i386
> 
> Personally I think it would be nice to store these in
> update-binfmts(8) style format files rather than directly
> in the script. That way we separate data from the
> implementation, and it's convenient if you want to do
> something else with the data than what the script does.

To separate data and implementation was my idea 2 years ago:
https://patchwork.ozlabs.org/patch/213887/
https://patchwork.ozlabs.org/patch/213886/

but it is easier to manage if all stuffs are in the same file.

The first idea is to keep compatibility of the original script by adding
only features. As I'd like to have a script working on
debian/fedora(suse?)/generic, we must keep the base format as simple as
possible. With this format, we are able to generate easily
update-binfmts format, systemd-binfmt.service format or to write
directly into /proc.

Regards,
Laurent
diff mbox

Patch

diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
old mode 100644
new mode 100755
index 289b1a3..f780f1a
--- a/scripts/qemu-binfmt-conf.sh
+++ b/scripts/qemu-binfmt-conf.sh
@@ -1,72 +1,300 @@ 
 #!/bin/sh
 # enable automatic i386/ARM/M68K/MIPS/SPARC/PPC/s390 program execution by the kernel
 
-# load the binfmt_misc module
-if [ ! -d /proc/sys/fs/binfmt_misc ]; then
-  /sbin/modprobe binfmt_misc
-fi
-if [ ! -f /proc/sys/fs/binfmt_misc/register ]; then
-  mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
-fi
-
-# probe cpu type
-cpu=`uname -m`
-case "$cpu" in
-  i386|i486|i586|i686|i86pc|BePC|x86_64)
-    cpu="i386"
-  ;;
-  m68k)
-    cpu="m68k"
-  ;;
-  mips*)
-    cpu="mips"
-  ;;
-  "Power Macintosh"|ppc|ppc64)
-    cpu="ppc"
-  ;;
-  armv[4-9]*)
-    cpu="arm"
-  ;;
-esac
-
-# register the interpreter for each cpu except for the native one
-if [ $cpu != "i386" ] ; then
-    echo ':i386:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-i386:' > /proc/sys/fs/binfmt_misc/register
-    echo ':i486:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06\x00:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-i386:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "alpha" ] ; then
-    echo ':alpha:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x26\x90:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-alpha:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "arm" ] ; then
-    echo   ':arm:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-arm:' > /proc/sys/fs/binfmt_misc/register
-    echo   ':armeb:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-armeb:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "aarch64" ] ; then
-    echo ':aarch64:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-aarch64:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "sparc" ] ; then
-    echo   ':sparc:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x02:\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-sparc:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "ppc" ] ; then
-    echo   ':ppc:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x14:\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-ppc:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "m68k" ] ; then
-    echo   'Please check cpu value and header information for m68k!'
-    echo   ':m68k:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x04:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-m68k:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "mips" ] ; then
-    # FIXME: We could use the other endianness on a MIPS host.
-    echo   ':mips:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-mips:' > /proc/sys/fs/binfmt_misc/register
-    echo   ':mipsel:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-mipsel:' > /proc/sys/fs/binfmt_misc/register
-    echo   ':mipsn32:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-mipsn32:' > /proc/sys/fs/binfmt_misc/register
-    echo   ':mipsn32el:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-mipsn32el:' > /proc/sys/fs/binfmt_misc/register
-    echo   ':mips64:M::\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-mips64:' > /proc/sys/fs/binfmt_misc/register
-    echo   ':mips64el:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-mips64el:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "sh" ] ; then
-    echo    ':sh4:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a\x00:\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-sh4:' > /proc/sys/fs/binfmt_misc/register
-    echo    ':sh4eb:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a:\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-sh4eb:' > /proc/sys/fs/binfmt_misc/register
-fi
-if [ $cpu != "s390x" ] ; then
-    echo   ':s390x:M::\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x16:\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/local/bin/qemu-s390x:' > /proc/sys/fs/binfmt_misc/register
-fi
+qemu_target_list="i386 i486 alpha arm sparc32plus ppc ppc64 m68k mips mipsel \
+                  mipsn32 mipsn32el mips64 mips64el sh4 sh4eb s390x aarch64"
+
+i386_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00'
+i386_mask='\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+i386_family=i386
+
+i486_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06\x00'
+i486_mask='\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+i486_family=i386
+
+alpha_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x26\x90'
+alpha_mask='\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+alpha_family=alpha
+
+arm_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28\x00'
+arm_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+arm_family=arm
+
+armeb_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28'
+armeb_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+armeb_family=arm
+
+sparc_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x02'
+sparc_mask='\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+sparc_family=sparc
+
+sparc32plus_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x12'
+sparc32plus_mask='\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+sparc32plus_family=sparc
+
+ppc_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x14'
+ppc_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+ppc_family=ppc
+
+ppc64_magic='\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x15'
+ppc64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+ppc64_family=ppc
+
+m68k_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x04'
+m68k_mask='\xff\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+m68k_family=m68k
+
+# FIXME: We could use the other endianness on a MIPS host.
+
+mips_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
+mips_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+mips_family=mips
+
+mipsel_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'
+mipsel_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+mipsel_family=mips
+
+mipsn32_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
+mipsn32_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+mipsn32_family=mips
+
+mipsn32el_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'
+mipsn32el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+mipsn32el_family=mips
+
+mips64_magic='\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'
+mips64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+mips64_family=mips
+
+mips64el_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'
+mips64el_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+mips64el_family=mips
+
+sh4_magic='\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a\x00'
+sh4_mask='\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+sh4_family=sh4
+
+sh4eb_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a'
+sh4eb_mask='\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+sh4eb_family=sh4
+
+s390x_magic='\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x16'
+s390x_mask='\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
+s390x_family=s390x
+
+aarch64_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00'
+aarch64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
+aarch64_family=aarch64
+
+qemu_get_family() {
+    cpu=$(uname -m)
+    case "$cpu" in
+    i386|i486|i586|i686|i86pc|BePC|x86_64)
+        echo "i386"
+        ;;
+    mips*)
+        echo "mips"
+        ;;
+    "Power Macintosh")
+        echo "ppc"
+        ;;
+    armv[4-9]*)
+        echo "arm"
+        ;;
+    sparc*)
+        echo "sparc"
+        ;;
+    *)
+        echo "$cpu"
+        ;;
+    esac
+}
+
+usage() {
+    cat <<!EOF
+Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian [--exportdir PATH]]
+                           [--help][--credential yes|no][--systemd CPU]
+
+       Configure binfmt_misc to use qemu interpreter
+
+       --help:       display this usage
+       --qemu-path:  set path to qemu interpreter ($QEMU_PATH)
+       --debian:     don't write into /proc,
+                     instead generate update-binfmts templates
+       --systemd:    don't write into /proc,
+                     instead generate file for systemd-binfmt.service
+                     for the given CPU
+       --exportdir:  define where to write update-binfmts templates
+                     ($EXPORTDIR)
+       --credential: if yes, credential an security tokens are
+                     calculated according to the binary to interpret
+
+    To import templates with update-binfmts, use :
+
+        sudo update-binfmts --importdir $EXPORTDIR --import qemu-CPU
+
+    To remove interpreter, use :
+
+        sudo update-binfmts --package qemu-CPU --remove qemu-CPU $QEMU_PATH
+
+    With systemd, binfmt files are loaded by systemd-binfmt.service
+
+    where CPU is one of:
+
+!EOF
+    echo -n "    "
+    for CPU in $qemu_target_list ;
+    do
+        echo -n "$CPU "
+    done
+    echo
+}
+
+qemu_check_bintfmt_misc() {
+    # load the binfmt_misc module
+    if [ ! -d /proc/sys/fs/binfmt_misc ]; then
+      if ! /sbin/modprobe binfmt_misc ; then
+          exit 1
+      fi
+    fi
+    if [ ! -f /proc/sys/fs/binfmt_misc/register ]; then
+      if ! mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc ; then
+          exit 1
+      fi
+    fi
+
+    if [ ! -w /proc/sys/fs/binfmt_misc/register ] ; then
+        echo "ERROR: cannot write to /proc/sys/fs/binfmt_misc/register" 1>&2
+        exit 1
+    fi
+}
+
+installed_dpkg() {
+    dpkg --status "$1" > /dev/null 2>&1
+}
+
+qemu_check_debian() {
+    if [ ! -e /etc/debian_version ] ; then
+        echo "ERROR: this script works only on Debian based distro" 1>&2
+        exit 1
+    fi
+    if ! installed_dpkg binfmt-support ; then
+        echo "ERROR: package binfmt-support is needed !" 1>&2
+        exit 1
+    fi
+}
+
+qemu_check_systemd() {
+    if ! systemctl -q is-enabled systemd-binfmt.service ; then
+        echo "ERROR: systemd-binfmt.service is missing or disabled !" 1>&2
+        exit 1
+    fi
+    if [ "$UID" != "0" ] ; then
+        echo "ERROR: you must be root to be able to write systemd configuration files !" 1>&2
+        exit 1
+    fi
+}
+
+qemu_register_interpreter() {
+    echo "Setting $qemu as binfmt interpreter for $cpu"
+    echo ":qemu-$cpu:M::$magic:$mask:$qemu:$FLAGS" > /proc/sys/fs/binfmt_misc/register
+}
+
+qemu_generate_systemd() {
+    echo "Setting $qemu as binfmt interpreter for $cpu for systemd-binfmt.service"
+    echo ":qemu-$cpu:M::$magic:$mask:$qemu:$FLAGS" > "/etc/binfmt.d/qemu-$cpu.conf"
+}
+
+qemu_generate_packages() {
+    cat > "$EXPORTDIR/qemu-$cpu" <<!EOF
+package qemu-$cpu
+interpreter $qemu
+magic $magic
+mask $mask
+!EOF
+    if [ "$FLAGS" = "OC" ] ; then
+        echo "credentials yes" >> "$EXPORTDIR/qemu-$cpu"
+    fi
+}
+
+qemu_set_binfmts() {
+    # probe cpu type
+    host_family=$(qemu_get_family)
+
+    # register the interpreter for each cpu except for the native one
+
+    for cpu in ${qemu_target_list} ; do
+        magic=$(eval echo \$${cpu}_magic)
+        mask=$(eval echo \$${cpu}_mask)
+        family=$(eval echo \$${cpu}_family)
+
+        if [ "$magic" = "" -o "$mask" = "" -o "$family" = "" ] ; then
+            echo "INTERNAL ERROR: unknown cpu $cpu" 1>&2
+            continue
+        fi
+
+        qemu="$QEMU_PATH/qemu-$cpu"
+        if [ "$cpu" = "i486" ] ; then
+            qemu="$QEMU_PATH/qemu-i386"
+        fi
+
+        if [ "$host_family" != "$family" ] ; then
+            $BINFMT_SET
+        fi
+    done
+}
+
+BINFMT_SET=qemu_register_interpreter
+QEMU_PATH=/usr/local/bin
+EXPORTDIR="/usr/share/binfmts"
+CHECK=qemu_check_bintfmt_misc
+FLAGS=""
+
+options=$(getopt -o ds:Q:e:hc: -l debian,systemd:,qemu-path:,exportdir:,help,credential: -- "$@")
+eval set -- "$options"
+
+while true ; do
+    case "$1" in
+    -d|--debian)
+        CHECK=qemu_check_debian
+        BINFMT_SET=qemu_generate_packages
+        ;;
+    -s|--systemd)
+        CHECK=qemu_check_systemd
+        BINFMT_SET=qemu_generate_systemd
+        shift
+        qemu_target_list="$1"
+        ;;
+    -Q|--qemu-path)
+        shift
+        QEMU_PATH="$1"
+        ;;
+    -e|--exportdir)
+        shift
+        EXPORTDIR="$1"
+        if [ ! -d "$EXPORTDIR" ] ; then
+            echo "ERROR: $EXPORTDIR doesn't exist" 1>&2
+            exit 1
+        fi
+        ;;
+    -h|--help)
+        usage
+        exit 1
+        ;;
+    -c|--credential)
+        shift
+        if [ "$1" = "yes" ] ; then
+            FLAGS="OC"
+        else
+            FLAGS=""
+        fi
+        ;;
+    *)
+        break
+        ;;
+    esac
+    shift
+done
+
+$CHECK
+qemu_set_binfmts