From 29fa1af29768c3d069a4b96dc5719a0214a9ed03 Mon Sep 17 00:00:00 2001
From: Andreas Grapentin <andreas@grapentin.org>
Date: Tue, 20 Mar 2018 20:54:00 +0100
Subject: [PATCH] add binfmt wrapper

---
 Makefile.target             |  9 ++++++++
 binfmt.c                    | 55 +++++++++++++++++++++++++++++++++++++++++++++
 scripts/qemu-binfmt-conf.sh | 10 ++++-----
 3 files changed, 68 insertions(+), 6 deletions(-)
 create mode 100644 binfmt.c

diff --git a/Makefile.target b/Makefile.target
index 6549481096..3edb4cc832 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -36,6 +36,10 @@ endif
 PROGS=$(QEMU_PROG) $(QEMU_PROGW)
 STPFILES=
 
+ifdef CONFIG_LINUX_USER
+PROGS+=$(QEMU_PROG)-binfmt
+endif
+
 config-target.h: config-target.h-timestamp
 config-target.h-timestamp: config-target.mak
 
@@ -114,6 +118,8 @@ QEMU_CFLAGS+=-I$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR) \
 obj-y += linux-user/
 obj-y += gdbstub.o thunk.o
 
+obj-binfmt-y += binfmt.o
+
 endif #CONFIG_LINUX_USER
 
 #########################################################
@@ -196,6 +202,9 @@ ifdef CONFIG_DARWIN
 	$(call quiet-command,SetFile -a C $@,"SETFILE","$(TARGET_DIR)$@")
 endif
 
+$(QEMU_PROG)-binfmt: $(obj-binfmt-y)
+	$(call LINK,$^)
+
 gdbstub-xml.c: $(TARGET_XML_FILES) $(SRC_PATH)/scripts/feature_to_c.sh
 	$(call quiet-command,rm -f $@ && $(SHELL) $(SRC_PATH)/scripts/feature_to_c.sh $@ $(TARGET_XML_FILES),"GEN","$(TARGET_DIR)$@")
 
diff --git a/binfmt.c b/binfmt.c
new file mode 100644
index 0000000000..9b19436ee5
--- /dev/null
+++ b/binfmt.c
@@ -0,0 +1,55 @@
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <string.h>
+#include <stdlib.h>
+
+int
+main (int argc, char **argv)
+{
+  if (argc < 3) {
+    fprintf(stderr, "%s: please use me through binfmt\n", argv[0]);
+    return 1;
+  }
+
+  char **nargv = malloc(sizeof(*argv) * (argc + 2));
+  if (NULL == nargv)
+    {
+      perror("malloc");
+      return 1;
+    }
+
+  nargv[0] = strdup(argv[0]);
+  if (NULL == nargv[0])
+    {
+      perror("strdup");
+      return 1;
+    }
+
+  // argv0 is qemu-$cpu-binfmt, and we want to change that to qemu-$cpu-static
+  char *dest = strstr(nargv[0], "-binfmt");
+  if (NULL == dest)
+    {
+      fprintf(stderr, "%s: -binfmt not found in invocation name\n", argv[0]);
+      return 1;
+    }
+  strncpy(dest, "-static", 7);
+
+  nargv[1] = strdup("-0");
+  if (NULL == nargv[1])
+    {
+      perror("strdup");
+      return 1;
+    }
+
+  nargv[2] = argv[2];
+  nargv[3] = argv[1];
+
+  memcpy(&nargv[4], &argv[3], (argc - 3 + 1) * sizeof(*argv));
+
+  int ret = execv(nargv[0], nargv);
+  perror("exec");
+  return ret;
+}
diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
index f39ad344fc..c36b1abd43 100755
--- a/scripts/qemu-binfmt-conf.sh
+++ b/scripts/qemu-binfmt-conf.sh
@@ -274,9 +274,9 @@ qemu_set_binfmts() {
             continue
         fi
 
-        qemu="$QEMU_PATH/qemu-$cpu"
+        qemu="$QEMU_PATH/qemu-$cpu-binfmt"
         if [ "$cpu" = "i486" ] ; then
-            qemu="$QEMU_PATH/qemu-i386"
+            qemu="$QEMU_PATH/qemu-i386-binfmt"
         fi
 
         if [ "$host_family" != "$family" ] ; then
@@ -292,7 +292,7 @@ SYSTEMDDIR="/etc/binfmt.d"
 DEBIANDIR="/usr/share/binfmts"
 
 QEMU_PATH=/usr/local/bin
-FLAGS=""
+FLAGS="P"
 
 options=$(getopt -o ds:Q:e:hc: -l debian,systemd:,qemu-path:,exportdir:,help,credential: -- "$@")
 eval set -- "$options"
@@ -341,9 +341,7 @@ while true ; do
     -c|--credential)
         shift
         if [ "$1" = "yes" ] ; then
-            FLAGS="OC"
-        else
-            FLAGS=""
+            FLAGS+="OC"
         fi
         ;;
     *)
-- 
2.16.2