[Qemu-devel] [PATCH v3 6/10] qemu-binfmt-conf.sh: generalize <CPU> to positional <CPUS>

[Unai Martinez-Corral <unai.martinezcorral@ehu.eus>]

This breaks brackward compatibility.

Option '--systemd CPU' allows to register binfmt interpreters for a
single target architecture or for 'ALL' (of them). This patch
generalizes the approach to support it in any mode (default, '--debian'
or '--systemd'). To do so, option 'systemd' is changed to be boolean
(no args). Then, all the positional arguments are considered to be a
list of target architectures.

The list can be separated by spaces, tabs, newlines or commas. If no
positional argument is provided, or when it is 'ALL', all of the
architectures in qemu_target_list are registered.

Conversely, argument value 'NONE' allows to make a 'dry run' of the
script. I.e., checks are executed according to the mode, but no
interpreter is registered.

Signed-off-by: Unai Martinez-Corral <unai.martinezcorral@ehu.eus>
---
 scripts/qemu-binfmt-conf.sh | 92 +++++++++++++++++++++++--------------
 1 file changed, 57 insertions(+), 35 deletions(-)

diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
index c113ff131e..2751363089 100755
--- a/scripts/qemu-binfmt-conf.sh
+++ b/scripts/qemu-binfmt-conf.sh
@@ -6,6 +6,36 @@ mips mipsel mipsn32 mipsn32el mips64 mips64el \
 sh4 sh4eb s390x aarch64 aarch64_be hppa riscv32 riscv64 xtensa xtensaeb \
 microblaze microblazeel or1k x86_64"

+# check if given target CPUS is/are in the supported target list
+qemu_check_target_list() {
+    all="$qemu_target_list"
+    if [ "x$1" = "xALL" ] ; then
+      checked_target_list="$all"
+      return
+    fi
+    list=""
+    bIFS="$IFS"
+    IFS=$"$IFS",
+    for target ; do
+        unknown_target="true"
+        for cpu in $all ; do
+            if [ "x$cpu" = "x$target" ] ; then
+                list="$list $target"
+                unknown_target="false"
+                break
+            fi
+        done
+        if [ "$unknown_target" = "true" ] ; then
+            IFS="$bIFS"
+            echo "ERROR: unknown CPU \"$target\"" 1>&2
+            usage
+            exit 1
+        fi
+    done
+    IFS="$bIFS"
+    checked_target_list="$list"
+}
+
 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\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
 i386_family=i386
@@ -167,11 +197,14 @@ qemu_get_family() {

 usage() {
     cat <<EOF
-Usage: qemu-binfmt-conf.sh [--path PATH][--debian][--systemd CPU]
+Usage: qemu-binfmt-conf.sh [--path PATH][--debian][--systemd]
                            [--help][--credential][--exportdir PATH]
-                           [--persistent][--suffix SUFFIX]
+                           [--persistent][--suffix SUFFIX][CPUS]

-       Configure binfmt_misc to use qemu interpreter
+       Configure binfmt_misc to use qemu interpreter for the given CPUS.
+       Supported formats for CPUS are: single arch or comma/space separated list.
+       See QEMU target list below. If CPUS is 'ALL' or empty, configure all known
+       cpus. If CPUS is 'NONE', no interpreter is configured.

        --help:        display this usage
        --path:        set path to qemu interpreter ($QEMU_PATH)
@@ -180,9 +213,10 @@ Usage: qemu-binfmt-conf.sh [--path PATH][--debian][--systemd CPU]
        --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. If CPU is "ALL", generate a
-                      file for all known cpus
+                      instead generate file for systemd-binfmt.service;
+                      environment variable HOST_ARCH allows to override 'uname'
+                      to generate configuration files for a different
+                      architecture than the current one.
        --exportdir:   define where to write configuration files
                       (default: $SYSTEMDDIR or $DEBIANDIR)
        --credential:  if present, credential and security tokens are
@@ -201,14 +235,7 @@ Usage: qemu-binfmt-conf.sh [--path PATH][--debian][--systemd CPU]

         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
+    QEMU target list: $qemu_target_list

 EOF
 }
@@ -289,12 +316,22 @@ EOF
 }

 qemu_set_binfmts() {
+    if [ "x$1" = "xNONE" ] ; then
+      return
+    fi
+
     # probe cpu type
     host_family=$(qemu_get_family)

+    # reduce the list of target interpreters to those given in the CLI
+    targets="$@"
+    if [ $# -eq 0 ] ; then
+      targets="ALL"
+    fi
+    qemu_check_target_list $targets
+
     # register the interpreter for each cpu except for the native one
-
-    for cpu in ${qemu_target_list} ; do
+    for cpu in $checked_target_list ; do
         magic=$(eval echo \$${cpu}_magic)
         mask=$(eval echo \$${cpu}_mask)
         family=$(eval echo \$${cpu}_family)
@@ -327,7 +364,7 @@ QEMU_SUFFIX="${QEMU_SUFFIX:-}"
 QEMU_CREDENTIAL="${QEMU_CREDENTIAL:-no}"
 QEMU_PERSISTENT="${QEMU_PERSISTENT:-no}"

-options=$(getopt -o ds:Q:S:e:hcp -l debian,systemd:,path:,suffix:,exportdir:,help,credential,persistent -- "$@")
+options=$(getopt -o :dsQ:S:e:hcp -l debian,systemd,path:,suffix:,exportdir:,help,credential,persistent -- "$@")
 eval set -- "$options"

 while true ; do
@@ -341,23 +378,6 @@ while true ; do
         CHECK=qemu_check_systemd
         BINFMT_SET=qemu_generate_systemd
         EXPORTDIR=${EXPORTDIR:-$SYSTEMDDIR}
-        shift
-        # check given cpu is in the supported CPU list
-        if [ "$1" != "ALL" ] ; then
-            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
-        fi
         ;;
     -Q|--path)
         shift
@@ -388,5 +408,7 @@ while true ; do
     shift
 done

+shift
+
 $CHECK
-qemu_set_binfmts
+qemu_set_binfmts "$@"
--
2.20.1