add module for testing module patching

A simple kernel module for testing basic kernel module patching.

Just run doit.sh from test/testmod.

Signed-off-by: Seth Jennings <sjenning@redhat.com>

test/testmod/Makefile

@@ -0,0 +1,23 @@
+BUILD ?= /lib/modules/$(shell uname -r)/build
+
+testmod.ko: testmod_drv.c
+	patch < patch
+	KCFLAGS="-ffunction-sections -fdata-sections" $(MAKE) -C $(BUILD) M=$(PWD) testmod.ko
+	strip --keep-file-symbols -d testmod_drv.o
+	cp testmod_drv.o testmod_drv.o.patched
+	patch -R < patch
+	KCFLAGS="-ffunction-sections -fdata-sections" $(MAKE) -C $(BUILD) M=$(PWD) testmod.ko
+	strip --keep-file-symbols -d testmod_drv.o
+	cp testmod_drv.o testmod_drv.o.orig
+	$(MAKE) -C $(BUILD) M=$(PWD) clean
+	$(MAKE) -C $(BUILD) M=$(PWD) testmod.ko
+
+all: testmod.ko
+
+clean:
+	$(MAKE) -C $(BUILD) M=$(PWD) clean
+	rm *.orig *.patched
+
+# kbuild rules
+obj-m := testmod.o
+testmod-y := testmod_drv.o

test/testmod/README

@@ -0,0 +1,4 @@
+To test, run ./doit.sh from the current directory.
+
+To test on a remote system, set remote system using REMOTE in doit.sh.
+Then run ./doit.sh.

test/testmod/doit-client.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+#set -x
+
+rmmod testmod 2> /dev/null
+rmmod kpatch 2> /dev/null
+insmod testmod.ko || exit 1
+insmod kpatch.ko || exit 1
+if [[ "$(cat /sys/kernel/testmod/value)" != "2" ]]
+then
+	exit 1
+fi
+insmod kpatch-patch.ko
+dmesg | tail
+if [[ "$(cat /sys/kernel/testmod/value)" != "3" ]]
+then
+	exit 1
+fi
+echo 0 > /sys/kernel/kpatch/patches/kpatch_patch/enabled
+rmmod kpatch-patch
+if [[ "$(cat /sys/kernel/testmod/value)" != "2" ]]
+then
+	exit 1
+fi
+rmmod kpatch
+rmmod testmod
+echo "SUCCESS"

test/testmod/doit.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+
+#set -x
+
+# If testing on a remote machine, set it here
+# Probably want to use preshared keys.
+
+unset REMOTE
+#REMOTE="192.168.100.150"
+
+cd ../../ || exit 1
+make clean || exit 1
+make || exit 1
+cd test/testmod || exit 1
+make || exit 1
+../../kpatch-build/create-diff-object testmod_drv.o.orig testmod_drv.o.patched testmod.ko output.o || exit 1
+cd ../../kmod/patch || exit 1
+make clean || exit 1
+cp ../../test/testmod/output.o . || exit 1
+make || exit 1
+cd ../../test/testmod
+
+if [[ -z "$REMOTE" ]]
+then
+	cp ../../kmod/core/kpatch.ko .
+	cp ../../kmod/patch/kpatch-patch.ko .
+	sudo ./doit-client.sh
+else
+	scp ../../kmod/core/kpatch.ko root@$REMOTE:~/. || exit 1
+	scp ../../kmod/patch/kpatch-patch.ko root@$REMOTE:~/. || exit 1
+	scp testmod.ko root@$REMOTE:~/. || exit 1
+	scp doit-client.sh root@$REMOTE:~/. || exit 1
+	ssh root@$REMOTE ./doit-client.sh
+fi

test/testmod/patch

@@ -0,0 +1,11 @@
+--- testmod_drv.c.orig	2014-06-02 16:49:49.428509600 -0500
++++ testmod_drv.c	2014-06-02 16:49:56.973656791 -0500
+@@ -11,7 +11,7 @@
+ static ssize_t value_show(struct kobject *kobj,
+                           struct kobj_attribute *attr, char *buf)
+ {
+-	return sprintf(buf, "%d\n", value);
++	return sprintf(buf, "%d\n", value+1);
+ }
+ 
+ static struct kobj_attribute testmod_value_attr = __ATTR_RO(value);

test/testmod/testmod_drv.c

@@ -0,0 +1,44 @@
+#define pr_fmt(fmt) "testmod: " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+
+static struct kobject *testmod_kobj;
+int value = 2;
+
+static ssize_t value_show(struct kobject *kobj,
+                          struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", value);
+}
+
+static struct kobj_attribute testmod_value_attr = __ATTR_RO(value);
+
+static int testmod_init(void)
+{
+	int ret;
+
+	testmod_kobj = kobject_create_and_add("testmod", kernel_kobj);
+	if (!testmod_kobj)
+		return -ENOMEM;
+
+	ret = sysfs_create_file(testmod_kobj, &testmod_value_attr.attr);
+	if (ret) {
+		kobject_put(testmod_kobj);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void testmod_exit(void)
+{
+	sysfs_remove_file(testmod_kobj, &testmod_value_attr.attr);
+	kobject_put(testmod_kobj);
+}
+
+module_init(testmod_init);
+module_exit(testmod_exit);
+MODULE_LICENSE("GPL");