Re: [Qemu-devel] [PATCH v3] linux-user: Fix qemu-binfmt-conf.h to store config across reboot

[Laurent Vivier]

Please, Alex, Michael:

We need your ack/review.

Thanks,
Laurent

Le 17/02/2016 10:59, Riku Voipio a écrit :
> Hi,
> 
> On 16 February 2016 at 00:47, Laurent Vivier <address@hidden> wrote:
>> Ping?
> 
> It looks good to me. But I'd like to see some ack/review from
> Alexander or Michael.
> 
> Riku
> 
>> Le 29/01/2016 17:07, Laurent Vivier a écrit :
>>> Original 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.
>>>
>>> List of supported CPU is:
>>>
>>> i386 i486 alpha arm sparc32plus ppc ppc64 ppc64le
>>> m68k mips mipsel mipsn32 mipsn32el mips64 mips64el
>>> sh4 sh4eb s390x aarch64
>>>
>>> Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU]
>>>                            [--help][--credential yes|no][--exportdir PATH]
>>>
>>>        Configure binfmt_misc to use qemu interpreter
>>>
>>>        --help:       display this usage
>>>        --qemu-path:  set path to qemu interpreter (/usr/local/bin)
>>>        --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 configuration files
>>>                      (default: /etc/binfmt.d or /usr/share/binfmts)
>>>        --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 /usr/share/binfmts --import qemu-CPU
>>>
>>>     To remove interpreter, use :
>>>
>>>         sudo update-binfmts --package qemu-CPU --remove qemu-CPU 
>>> /usr/local/bin
>>>
>>>     With systemd, binfmt files are loaded by systemd-binfmt.service
>>>
>>>     The environment variable HOST_ARCH allows to override 'uname' to 
>>> generate
>>>     configuration files for a different architecture than the current one.
>>>
>>> Signed-off-by: Laurent Vivier <address@hidden>
>>> ---
>>> v3: change subject to be shorter
>>>     fix typo
>>>     remove "!EOF", "echo -n" and "[ ... -o ... ]"
>>>     check cpu given by --systemd is in the list
>>> v2: replace some ERRORS by WARNINGS to be able to use the script inside a 
>>> package build
>>>     check only the right to write in the directory, no need to be root
>>>     merge systemd and binfmt_misc configuration generation
>>>     s/qemu_generate_packages/qemu_generate_debian/
>>>     add support of HOST_ARCH from debian, and update CPU families.
>>>     allow to use --exportdir with --systemd and update "Usage".
>>>
>>>  scripts/qemu-binfmt-conf.sh | 389 
>>> ++++++++++++++++++++++++++++++++++++--------
>>>  1 file changed, 320 insertions(+), 69 deletions(-)
>>>  mode change 100644 => 100755 scripts/qemu-binfmt-conf.sh
>>>
>>> diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
>>> old mode 100644
>>> new mode 100755
>>> index 289b1a3..de4d1c1
>>> --- a/scripts/qemu-binfmt-conf.sh
>>> +++ b/scripts/qemu-binfmt-conf.sh
>>> @@ -1,72 +1,323 @@
>>>  #!/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 ppc64le 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
>>> +
>>> +ppc64le_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x15\x00'
>>> +ppc64le_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\x00'
>>> +ppc64le_family=ppcle
>>> +
>>> +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=arm
>>> +
>>> +qemu_get_family() {
>>> +    cpu=${HOST_ARCH:-$(uname -m)}
>>> +    case "$cpu" in
>>> +    amd64|i386|i486|i586|i686|i86pc|BePC|x86_64)
>>> +        echo "i386"
>>> +        ;;
>>> +    mips*)
>>> +        echo "mips"
>>> +        ;;
>>> +    "Power Macintosh"|ppc64|powerpc|ppc)
>>> +        echo "ppc"
>>> +        ;;
>>> +    ppc64el|ppc64le)
>>> +        echo "ppcle"
>>> +        ;;
>>> +    arm|armel|armhf|arm64|armv[4-9]*)
>>> +        echo "arm"
>>> +        ;;
>>> +    sparc*)
>>> +        echo "sparc"
>>> +        ;;
>>> +    *)
>>> +        echo "$cpu"
>>> +        ;;
>>> +    esac
>>> +}
>>> +
>>> +usage() {
>>> +    cat <<EOF
>>> +Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU]
>>> +                           [--help][--credential yes|no][--exportdir PATH]
>>> +
>>> +       Configure binfmt_misc to use qemu interpreter
>>> +
>>> +       --help:       display this usage
>>> +       --qemu-path:  set path to qemu interpreter ($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 configuration files
>>> +                     (default: $SYSTEMDDIR or $DEBIANDIR)
>>> +       --credential: if yes, credential and security tokens are
>>> +                     calculated according to the binary to interpret
>>> +
>>> +    To import templates with update-binfmts, use :
>>> +
>>> +        sudo update-binfmts --importdir ${EXPORTDIR:-$DEBIANDIR} --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
>>> +
>>> +    The environment variable HOST_ARCH allows to override 'uname' to 
>>> generate
>>> +    configuration files for a different architecture than the current one.
>>> +
>>> +    where CPU is one of:
>>> +
>>> +        $qemu_target_list
>>> +
>>> +EOF
>>> +}
>>> +
>>> +qemu_check_access() {
>>> +    if [ ! -w "$1" ] ; then
>>> +        echo "ERROR: cannot write to $1" 1>&2
>>> +        exit 1
>>> +    fi
>>> +}
>>> +
>>> +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
>>> +
>>> +    qemu_check_access /proc/sys/fs/binfmt_misc/register
>>> +}
>>> +
>>> +installed_dpkg() {
>>> +    dpkg --status "$1" > /dev/null 2>&1
>>> +}
>>> +
>>> +qemu_check_debian() {
>>> +    if [ ! -e /etc/debian_version ] ; then
>>> +        echo "WARNING: your system is not a Debian based distro" 1>&2
>>> +    elif ! installed_dpkg binfmt-support ; then
>>> +        echo "WARNING: package binfmt-support is needed" 1>&2
>>> +    fi
>>> +    qemu_check_access "$EXPORTDIR"
>>> +}
>>> +
>>> +qemu_check_systemd() {
>>> +    if ! systemctl -q is-enabled systemd-binfmt.service ; then
>>> +        echo "WARNING: systemd-binfmt.service is missing or disabled" 1>&2
>>> +    fi
>>> +    qemu_check_access "$EXPORTDIR"
>>> +}
>>> +
>>> +qemu_generate_register() {
>>> +    echo ":qemu-$cpu:M::$magic:$mask:$qemu:$FLAGS"
>>> +}
>>> +
>>> +qemu_register_interpreter() {
>>> +    echo "Setting $qemu as binfmt interpreter for $cpu"
>>> +    qemu_generate_register > /proc/sys/fs/binfmt_misc/register
>>> +}
>>> +
>>> +qemu_generate_systemd() {
>>> +    echo "Setting $qemu as binfmt interpreter for $cpu for 
>>> systemd-binfmt.service"
>>> +    qemu_generate_register > "$EXPORTDIR/qemu-$cpu.conf"
>>> +}
>>> +
>>> +qemu_generate_debian() {
>>> +    cat > "$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 [ "$magic" = "" ] || [ "$mask" = "" ] || [ "$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
>>> +            $BINFMT_SET
>>> +        fi
>>> +    done
>>> +}
>>> +
>>> +CHECK=qemu_check_bintfmt_misc
>>> +BINFMT_SET=qemu_register_interpreter
>>> +
>>> +SYSTEMDDIR="/etc/binfmt.d"
>>> +DEBIANDIR="/usr/share/binfmts"
>>> +
>>> +QEMU_PATH=/usr/local/bin
>>> +FLAGS=""
>>> +
>>> +options=$(getopt -o ds:Q:e:hc: -l 
>>> debian,systemd:,qemu-path:,exportdir:,help,credential: -- "$@")
>>> +eval set -- "$options"
>>> +
>>> +while true ; do
>>> +    case "$1" in
>>> +    -d|--debian)
>>> +        CHECK=qemu_check_debian
>>> +        BINFMT_SET=qemu_generate_debian
>>> +        EXPORTDIR=${EXPORTDIR:-$DEBIANDIR}
>>> +        ;;
>>> +    -s|--systemd)
>>> +        CHECK=qemu_check_systemd
>>> +        BINFMT_SET=qemu_generate_systemd
>>> +        EXPORTDIR=${EXPORTDIR:-$SYSTEMDDIR}
>>> +        shift
>>> +        # check given cpu is in the supported CPU list
>>> +        for cpu in ${qemu_target_list} ; do
>>> +            if [ "$cpu" == "$1" ] ; then
>>> +                break
>>> +            fi
>>> +        done
>>> +
>>> +        if [ "$cpu" == "$1" ] ; then
>>> +            qemu_target_list="$1"
>>> +        else
>>> +            echo "ERROR: unknown CPU \"$1\"" 1>&2
>>> +            usage
>>> +            exit 1
>>> +        fi
>>> +        ;;
>>> +    -Q|--qemu-path)
>>> +        shift
>>> +        QEMU_PATH="$1"
>>> +        ;;
>>> +    -e|--exportdir)
>>> +        shift
>>> +        EXPORTDIR="$1"
>>> +        ;;
>>> +    -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
>>>
>