[patch] binfmt wrapper

qemu-9999-binfmt-wrapper.patch (text/plain), 2.35 KB, created by Andrew Aladjev on 2014-07-05 15:32:18 UTC

diff --git a/Makefile.target b/Makefile.target
old mode 100755
new mode 100644
index ba12340..8e87b8e
--- a/Makefile.target
+++ b/Makefile.target
@@ -31,6 +31,10 @@ PROGS+=$(QEMU_PROGW)
 endif
 STPFILES=
 
+ifdef CONFIG_LINUX_USER
+PROGS+=$(QEMU_PROG)-binfmt-wrapper
+endif
+
 config-target.h: config-target.h-timestamp
 config-target.h-timestamp: config-target.mak
 
@@ -92,6 +96,8 @@ QEMU_CFLAGS+=-I$(SRC_PATH)/linux-user/$(TARGET_ABI_DIR) -I$(SRC_PATH)/linux-user
 obj-y += linux-user/
 obj-y += gdbstub.o thunk.o user-exec.o
 
+obj-binfmt-wrapper-y += linux-user/binfmt-wrapper.o
+
 endif #CONFIG_LINUX_USER
 
 #########################################################
@@ -173,6 +179,9 @@ $(QEMU_PROG): $(all-obj-y) ../libqemuutil.a ../libqemustub.a
 	$(call LINK,$^)
 endif
 
+$(QEMU_PROG)-binfmt-wrapper: $(obj-binfmt-wrapper-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/linux-user/binfmt-wrapper.c b/linux-user/binfmt-wrapper.c
new file mode 100644
index 0000000..ce3c1bd
--- /dev/null
+++ b/linux-user/binfmt-wrapper.c
@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <string.h>
+#include <stdlib.h>
+
+int main ( int argc, char ** argv, char ** envp )
+{
+    char * binfmt;
+    char ** new_argv;
+
+    // Check if our file name ends with -binfmt-wrapper
+    binfmt = argv[0] + strlen( argv[0] ) - strlen ( "-binfmt-wrapper" );
+    if ( strcmp ( binfmt, "-binfmt-wrapper" ) ) {
+        fprintf ( stderr, "%s: Invalid executable name\n", argv[0] );
+        return 1;
+    }
+    if ( argc < 3 ) {
+        fprintf ( stderr, "%s: Please use me through binfmt with P flag\n", argv[0] );
+        return 2;
+    }
+
+    binfmt[0] = '\0';
+    // Now argv[0] is the real qemu binary name
+
+    new_argv = ( char ** ) malloc ( ( argc + 2 ) * sizeof ( * new_argv ) );
+    if ( argc > 3 ) {
+        memcpy ( &new_argv[4], &argv[3], ( argc - 3 ) * sizeof ( * new_argv ) );
+    }
+    new_argv[0]        = argv[0];
+    new_argv[1]        = ( char * ) "-0";
+    new_argv[2]        = argv[2];
+    new_argv[3]        = argv[1];
+    new_argv[argc + 1] = NULL;
+
+    return execve ( new_argv[0], new_argv, envp );
+}
\ No newline at end of file