[Qemu-devel] [PATCH v3] scripts/qemu-binfmt-conf.sh: add bFLT handler registration

[Qemu-devel] [PATCH v3] scripts/qemu-binfmt-conf.sh: add bFLT handler registration

[Max Filippov]

bFLT format header doesn't have enough information to register a handler
for a specific architecture. Add switch -f / --flat that registers one
of the qemu binaries as a handler for bFLT executable images.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
Changes v2->v3:
- fix bFLT in the patch subject

Changes v1->v2:
- drop unintended changes to dtc;

 scripts/qemu-binfmt-conf.sh | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
index b5a16742a149..39f61065c698 100755
--- a/scripts/qemu-binfmt-conf.sh
+++ b/scripts/qemu-binfmt-conf.sh
@@ -132,6 +132,9 @@ or1k_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\
 or1k_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
 or1k_family=or1k
 
+flat_magic='bFLT\x00\x00\x00\x04'
+flat_mask='\xff\xff\xff\xff\xff\xff\xff\xff'
+
 qemu_get_family() {
     cpu=${HOST_ARCH:-$(uname -m)}
     case "$cpu" in
@@ -170,6 +173,7 @@ usage() {
 Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU]
                            [--help][--credential yes|no][--exportdir PATH]
                            [--persistent yes|no][--qemu-suffix SUFFIX]
+                           [--flat CPU]
 
        Configure binfmt_misc to use qemu interpreter
 
@@ -188,7 +192,9 @@ Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU]
                       calculated according to the binary to interpret
        --persistent:  if yes, the interpreter is loaded when binfmt is
                       configured and remains in memory. All future uses
-                      are cloned from the open file.
+                      are cloned from the open file
+       --flat:        register QEMU for this CPU architecture as a handler
+                      for the bFLT executable format.
 
     To import templates with update-binfmts, use :
 
@@ -311,6 +317,13 @@ qemu_set_binfmts() {
             $BINFMT_SET
         fi
     done
+    if [ -n "$QEMU_FLAT" ] ; then
+        cpu="${QEMU_FLAT}_bflt"
+        qemu="$QEMU_PATH/qemu-$QEMU_FLAT"
+        magic=$flat_magic
+        mask=$flat_mask
+        $BINFMT_SET
+    fi
 }
 
 CHECK=qemu_check_bintfmt_misc
@@ -324,7 +337,7 @@ CREDENTIAL=no
 PERSISTENT=no
 QEMU_SUFFIX=""
 
-options=$(getopt -o ds:Q:S:e:hc:p: -l debian,systemd:,qemu-path:,qemu-suffix:,exportdir:,help,credential:,persistent: -- "$@")
+options=$(getopt -o ds:Q:S:e:hc:p:f: -l debian,systemd:,qemu-path:,qemu-suffix:,exportdir:,help,credential:,persistent:,flat: -- "$@")
 eval set -- "$options"
 
 while true ; do
@@ -380,6 +393,21 @@ while true ; do
         shift
         PERSISTENT="$1"
         ;;
+    -f|--flat)
+        shift
+        QEMU_FLAT="$1"
+        for cpu in ${qemu_target_list} ; do
+            if [ "$cpu" = "$1" ] ; then
+                break
+            fi
+        done
+
+        if [ "$cpu" != "$1" ] ; then
+            echo "ERROR: unknown CPU \"$1\"" 1>&2
+            usage
+            exit 1
+        fi
+        ;;
     *)
         break
         ;;
-- 
2.11.0

Re: [Qemu-devel] [PATCH v3] scripts/qemu-binfmt-conf.sh: add bFLT handler registration

[Laurent Vivier]

On 21/10/2018 17:55, Max Filippov wrote:
> bFLT format header doesn't have enough information to register a handler
> for a specific architecture. Add switch -f / --flat that registers one
> of the qemu binaries as a handler for bFLT executable images.
> 
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
> Changes v2->v3:
> - fix bFLT in the patch subject
> 
> Changes v1->v2:
> - drop unintended changes to dtc;
> 
>  scripts/qemu-binfmt-conf.sh | 32 ++++++++++++++++++++++++++++++--
>  1 file changed, 30 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
> index b5a16742a149..39f61065c698 100755
> --- a/scripts/qemu-binfmt-conf.sh
> +++ b/scripts/qemu-binfmt-conf.sh
> @@ -132,6 +132,9 @@ or1k_magic='\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\
>  or1k_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'
>  or1k_family=or1k
>  
> +flat_magic='bFLT\x00\x00\x00\x04'
> +flat_mask='\xff\xff\xff\xff\xff\xff\xff\xff'
> +
>  qemu_get_family() {
>      cpu=${HOST_ARCH:-$(uname -m)}
>      case "$cpu" in
> @@ -170,6 +173,7 @@ usage() {
>  Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU]
>                             [--help][--credential yes|no][--exportdir PATH]
>                             [--persistent yes|no][--qemu-suffix SUFFIX]
> +                           [--flat CPU]
>  
>         Configure binfmt_misc to use qemu interpreter
>  
> @@ -188,7 +192,9 @@ Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU]
>                        calculated according to the binary to interpret
>         --persistent:  if yes, the interpreter is loaded when binfmt is
>                        configured and remains in memory. All future uses
> -                      are cloned from the open file.
> +                      are cloned from the open file
> +       --flat:        register QEMU for this CPU architecture as a handler
> +                      for the bFLT executable format.
>  
>      To import templates with update-binfmts, use :
>  
> @@ -311,6 +317,13 @@ qemu_set_binfmts() {
>              $BINFMT_SET
>          fi
>      done
> +    if [ -n "$QEMU_FLAT" ] ; then
> +        cpu="${QEMU_FLAT}_bflt"

I think you don't need this, you can let the user to use "--qemu-suffix"
for that.

Thanks,
Laurent

Re: [Qemu-devel] [PATCH v3] scripts/qemu-binfmt-conf.sh: add bFLT handler registration

[Laurent Vivier]

On 21/10/2018 17:55, Max Filippov wrote:
> bFLT format header doesn't have enough information to register a handler
> for a specific architecture. Add switch -f / --flat that registers one
> of the qemu binaries as a handler for bFLT executable images.
> 
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
> Changes v2->v3:
> - fix bFLT in the patch subject
> 
> Changes v1->v2:
> - drop unintended changes to dtc;
> 
>  scripts/qemu-binfmt-conf.sh | 32 ++++++++++++++++++++++++++++++--
>  1 file changed, 30 insertions(+), 2 deletions(-)


BTW, I'm not sure it's the good way to do that. The script has been
written with ELF in mind and no other alternative format.

Perhaps we can add a format parameter, like "--format elf" (default),
"--format bflt"  and then take the availabled CPU and mask/magic from
the list corresponding for the selected format.

And then rename qemu_set_binfmts() to qemu_elf_set_binfmts(), add
function qemu_bflt_set_binfmt() and call the one you you need according
the format you have selected.

Somehing like:

FORMAT_BINFMT_MISC_SET=qemu_elf_set_binfmts
...
    -F|--format)
       shift
       FORMAT_BINFMT_MISC_SET=qemu_$1_set_binfmts
       ;;
...

$CHECK
$FORMAT_BINFMT_MISC_SET

and then

qemu_bflt_set_binfmts()
{
   for cpu in ${qemu_target_list} ; do
       magic='bFLT\x00\x00\x00\x04'
       mask='\xff\xff\xff\xff\xff\xff\xff\xff'
       qemu="$QEMU_PATH/qemu-$cpu"
       qemu="$qemu$QEMU_SUFFIX"
       $BINFMT_SET
   done
}

Then with --systemd you provide only the cpu you want to generate, with
--debian you use update-binfmts to select the only one to import, for
/proc case we could add another parameter to only register one
interpreter (--proc CPU ?)

Thanks,
Laurent