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References: <1454011696-2119-1-git-send-email-laurent@vivier.eu>
From: Alexander Graf <agraf@suse.de>
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Date: Thu, 28 Jan 2016 21:20:11 +0100
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Subject: Re: [Qemu-devel] [PATCH] linux-user: Original qemu-binfmt-conf.h is
 only able to write configuration into /proc/sys/fs/binfmt_misc,
 and the configuration is lost on reboot.
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To: Laurent Vivier <laurent@vivier.eu>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, riku.voipio@linaro.org, mjt@tls.msk.ru



On 01/28/2016 09:08 PM, Laurent Vivier wrote:
> 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 [--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 (/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 update-binfmts templates
>                       (/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
>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>   scripts/qemu-binfmt-conf.sh | 371 ++++++++++++++++++++++++++++++++++++--------
>   1 file changed, 302 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..f34b282
> --- a/scripts/qemu-binfmt-conf.sh
> +++ b/scripts/qemu-binfmt-conf.sh
> @@ -1,72 +1,305 @@
>   #!/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=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

One envisioned use case of this script would be file generation inside 
of a package build. During the package build, there may not be systemd 
running at all - or it might just be a chroot.

So this check needs to be optional :).

> +    if [ "$UID" != "0" ] ; then
> +        echo "ERROR: you must be root to be able to write systemd configuration files !" 1>&2
> +        exit 1
> +    fi

Better check the directory permissions and see whether you have write 
access to /etc/binfmt.d?

> +}
> +
> +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"

This is duplicating the binfmt lines. While not terrible, I think it'd 
be awesome if we could move it out into a separate function that gets 
called from the self-register and systemd-register functions.

> +}
> +
> +qemu_generate_packages() {

This is the debian version, right? Should be reflected in its function name.

> +    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)

Debian had quite sophisticated groupings and logic to not register 
certain handlers under certain circumstances. Michael, can you please 
double-check that we're not regressing for you guys?

> +
> +        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

Ah, nice, so the old behavior does get preserved. Great :)

Alex