hook-helper: repurpose third arg for skip options now that qemu-user info does not need to be propagated anymore (was only needed for proot)

mmdebstrap

@@ -1755,7 +1755,8 @@ sub run_hooks {
                     # does for python
                     my @args = shellwords $script;
                     hookhelper($options->{root}, $options->{mode}, $name,
-                        $options->{qemu}, $verbosity_level, @args);
+                        (join ',', @{ $options->{skip} }),
+                        $verbosity_level, @args);
                     exit 0;
                 }
                 waitpid($pid, 0);
@@ -3356,8 +3357,20 @@ sub pivot_root {
 }
 
 sub hookhelper {
-    my ($root, $mode, $hook, $qemu, $verbosity, $command, @args) = @_;
+    my ($root, $mode, $hook, $skipopt, $verbosity, $command, @args) = @_;
     $verbosity_level = $verbosity;
+    my @skipopts = ();
+    if (length $skipopt) {
+        for my $skip (split /[,\s]+/, $skipopt) {
+            # strip leading and trailing whitespace
+            $skip =~ s/^\s+|\s+$//g;
+            # skip if the remainder is an empty string
+            if ($skip eq '') {
+                next;
+            }
+            push @skipopts, $skip;
+        }
+    }
     # we put everything in an eval block because that way we can easily handle
     # errors without goto labels or much code duplication: the error handler
     # has to send an "error" message to the other side

tests/special-hooks-using-helpers

@@ -8,7 +8,7 @@ mkdir /tmp/root/real
 run_testA() {
   echo content > /tmp/foo
   # shellcheck disable=SC2094
-  { { { {{ CMD }} --hook-helper /tmp/root root setup env 1 upload /tmp/foo "$1" < /tmp/myfifo 3>&-; echo $? >&3; printf "\\000\\000adios";
+  { { { {{ CMD }} --hook-helper /tmp/root root setup '' 1 upload /tmp/foo "$1" < /tmp/myfifo 3>&-; echo $? >&3; printf "\\000\\000adios";
       } | {{ CMD }} --hook-listener 1 3>&- >/tmp/myfifo; echo $?; } 3>&1;
   } | { read -r xs1; [ "$xs1" -eq 0 ]; read -r xs2; [ "$xs2" -eq 0 ]; }
   echo content | diff -u - /tmp/root/real/foo

tests/special-hooks-using-helpers-and-env-vars

@@ -8,12 +8,12 @@ echo "MMDEBSTRAP_APT_CONFIG $MMDEBSTRAP_APT_CONFIG"
 echo "$MMDEBSTRAP_HOOK" >> /tmp/hooks
 [ "$MMDEBSTRAP_MODE" = "root" ]
 echo test-content $MMDEBSTRAP_HOOK > test
-{{ CMD }} --hook-helper "$1" "$MMDEBSTRAP_MODE" "$MMDEBSTRAP_HOOK" env 1 upload test /test <&$MMDEBSTRAP_HOOKSOCK >&$MMDEBSTRAP_HOOKSOCK
+{{ CMD }} --hook-helper "$1" "$MMDEBSTRAP_MODE" "$MMDEBSTRAP_HOOK" '' 1 upload test /test <&$MMDEBSTRAP_HOOKSOCK >&$MMDEBSTRAP_HOOKSOCK
 rm test
 echo "content inside chroot:"
 cat "$1/test"
 [ "test-content $MMDEBSTRAP_HOOK" = "$(cat "$1/test")" ]
-{{ CMD }} --hook-helper "$1" "$MMDEBSTRAP_MODE" "$MMDEBSTRAP_HOOK" env 1 download /test test <&$MMDEBSTRAP_HOOKSOCK >&$MMDEBSTRAP_HOOKSOCK
+{{ CMD }} --hook-helper "$1" "$MMDEBSTRAP_MODE" "$MMDEBSTRAP_HOOK" '' 1 download /test test <&$MMDEBSTRAP_HOOKSOCK >&$MMDEBSTRAP_HOOKSOCK
 echo "content outside chroot:"
 cat test
 [ "test-content $MMDEBSTRAP_HOOK" = "$(cat test)" ]