From: Martin Wilck <mwilck@suse.com>
Date: Wed, 19 May 2021 17:24:45 +0200
Subject: qemu-binfmt-conf.sh: allow overriding SUSE-specific argv[0] handling

Git-commit: 0000000000000000000000000000000000000000
References: bsc#1186256

Since abbc0ce ("qemu-binfmt-conf: use qemu-ARCH-binfmt"),
qemu-binfmt-conf.sh automatically replaces the default qemu binfmt wrapper
qemu-$ARCH with qemu-$ARCH-binfmt in order to ensure that argv[0] is
preserved; qemu-$ARCH-binfmt is a link to qemu-binfmt, which is just a
simple wrapper that mangles argv to achieve the desired result.

This is inconvenient in some situations. In particular for running
foreign-arch containers, it's useful to use the binfmt_misc "F" ("fix
binary") flag to pre-load the qemu wrapper in the kernel. That way,
foreign-arch containers can be run just like native containers, without
having to bind-mount interpreters into the container. But that's impossible
with the SUSE binfmt wrapper that needs to exec() a different (native)
executable.

As the qemu-binfmt-conf script supports the --qemu-suffix option anyway,
use it to set the "-binfmt" suffix, thus allowing admins to override the
SUSE default with the option "--qemu-suffix ''".

Signed-off-by: Martin Wilck <mwilck@suse.com>
Acked-by: Jose R Ziviani <jose.ziviani@suse.com>
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
---
 scripts/qemu-binfmt-conf.sh | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
index a73232edfd7f9dedb3a7c32218fb..93e2c7c83fded06c598b8e844464 100755
--- a/scripts/qemu-binfmt-conf.sh
+++ b/scripts/qemu-binfmt-conf.sh
@@ -185,6 +185,7 @@ Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU]
        --help:          display this usage
        --qemu-path:     set path to qemu interpreter ($QEMU_PATH)
        --qemu-suffix:   add a suffix to the default interpreter name
+                        (default: "-binfmt")
        --debian:        don't write into /proc,
                         instead generate update-binfmts templates
        --systemd:       don't write into /proc,
@@ -316,9 +317,9 @@ qemu_set_binfmts() {
             continue
         fi
 
-        qemu="$QEMU_PATH/qemu-$cpu-binfmt"
+        qemu="$QEMU_PATH/qemu-$cpu"
         if [ "$cpu" = "i486" ] ; then
-            qemu="$QEMU_PATH/qemu-i386-binfmt"
+            qemu="$QEMU_PATH/qemu-i386"
         fi
 
         qemu="$qemu$QEMU_SUFFIX"
@@ -338,7 +339,7 @@ QEMU_PATH=/usr/bin
 CREDENTIAL=no
 PERSISTENT=no
 PRESERVE_ARG0=no
-QEMU_SUFFIX=""
+QEMU_SUFFIX="-binfmt"
 
 options=$(getopt -o ds:Q:S:e:hc:p:g:F: -l debian,systemd:,qemu-path:,qemu-suffix:,exportdir:,help,credential:,persistent:,preserve-argv0: -- "$@")
 eval set -- "$options"