Start building standalone falco kernel modules. (#789)

* Start building standalone falco kernel modules.

falcosecurity/falco#215 pointed out a problem with
compatibility between latest sysdig kernel module and falco 0.5.0. The
(newer) driver had different events than falco was expecting, causing a
crash.

To fix this, I'm changing falco to package its own driver. It was
already building its own driver, but the remaining changes are to change
the device name from sysdig to falco, module falco-probe, etc.

These changes will allow for automatically building the falco-probe
kernel module on a variety of kernel platforms and running
sysdig-probe-loader (under the name falco-probe-loader) to get a module
as needed.

While doing this, merge the nearly identical
build_{falco,sysdig,sysdigcloud} functions into build_probe. It now does
the work of checking out the right code based on the PROBE_* variables,
runs make driver from the main code repository, and verifies it can be
loaded.

* Add autoconf for falco builds.

The falco builds need autoconf so add it to the set of installed yum
packages.

scripts/Dockerfile.ol6

@@ -5,6 +5,7 @@ RUN yum -y install \
     git \
     gcc \
     gcc-c++ \
+    autoconf \
     make \
     cmake \
     libdtrace-ctf \

scripts/Dockerfile.ol7

@@ -5,6 +5,7 @@ RUN yum -y install \
     git \
     gcc \
     gcc-c++ \
+    autoconf \
     make \
     cmake \
     libdtrace-ctf \

scripts/build-probe-binaries

@@ -29,106 +29,65 @@ if [ ! -d $BASEDIR/output ]; then
 	mkdir $BASEDIR/output
 fi
 
-function build_probe {
-	if [ "$PROBE_NAME" = "sysdig-probe" ]; then
-		build_sysdig
-	elif [ "$PROBE_NAME" = "sysdigcloud-probe" ]; then
-		build_sysdigcloud
-	else
-		exit 1
-	fi
-}
-
-function build_sysdig {
-
-	if [ ! -f $BASEDIR/output/$PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH.ko ] || [ ! -f $BASEDIR/output/$PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH_ORIG.ko ]; then
-
-		echo Building $PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH.ko [${FUNCNAME[1]}]
-
-		if [ ! -d sysdig ]; then
-			git clone [email protected]:draios/sysdig.git
-		fi
+if [ $PROBE_NAME = "sysdigcloud-probe" ]; then
+        PROBE_REPO_NAME="agent"
+else
+        PROBE_REPO_NAME=$(echo $PROBE_NAME | cut -f1 -d-)
+fi
 
-		cd sysdig
-		git checkout master
-		# The UEK builder container doesn't have git credentials
-		# It relies on the non-UEK builds doing the pull earlier
-		if [[ ! "$KERNEL_TYPE" =~ "UEK" ]]; then
-			git pull
-		fi
-		git checkout $PROBE_VERSION
-		make -C driver clean || true
-		rm -rf build || true
-		mkdir build
-		cd build
-		cmake -DCMAKE_BUILD_TYPE=Release -DSYSDIG_VERSION=$PROBE_VERSION ..
-		make driver
-		strip -g driver/$PROBE_NAME.ko
+function update_code_for {
+        repo=$1
+	if [ ! -d $repo ]; then
+                git clone [email protected]:draios/$repo.git
+	fi
 
-		KO_VERSION=$(/sbin/modinfo driver/$PROBE_NAME.ko | grep vermagic | tr -s " " | cut -d " " -f 2)
-		if [ "$KO_VERSION" != "$KERNEL_RELEASE" ]; then
-			echo "Corrupted probe, KO_VERSION " $KO_VERSION ", KERNEL_RELEASE " $KERNEL_RELEASE
-			exit 1
-		fi
+	cd $repo
+	git checkout master
+	# The UEK builder container doesn't have git credentials
+	# It relies on the non-UEK builds doing the pull earlier
+	if [[ ! "$KERNEL_TYPE" =~ "UEK" ]]; then
+	        git pull
+	fi
 
-		cp driver/$PROBE_NAME.ko $BASEDIR/output/$PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH.ko
-		cp driver/$PROBE_NAME.ko $BASEDIR/output/$PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH_ORIG.ko
+	if [ $PROBE_REPO_NAME = $repo ]; then
+	        git checkout $PROBE_VERSION
 	else
-		echo Skipping $PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH.ko \(already built\)
+	        git checkout $PROBE_REPO_NAME/$PROBE_VERSION
 	fi
 
-	cd $BASEDIR
+	# Remove everything other than the files actually belonging to
+	# the repo.
+	git clean -d -f -x
+
+	# Reset the state of the files belonging to the repo to the
+	# state associated with the tag.
+	git reset --hard
+
+	cd ..
 }
 
-function build_sysdigcloud {
+function build_probe {
 
 	if [ ! -f $BASEDIR/output/$PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH.ko ] || [ ! -f $BASEDIR/output/$PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH_ORIG.ko ]; then
 
 		echo Building $PROBE_NAME-$PROBE_VERSION-$ARCH-$KERNEL_RELEASE-$HASH.ko [${FUNCNAME[1]}]
 
-		if [ ! -d sysdig ]; then
-			git clone [email protected]:draios/sysdig.git
-		fi
-
-		if [ ! -d falco ]; then
-			git clone [email protected]:draios/falco.git
-		fi
+		update_code_for sysdig
 
-		if [ ! -d agent ]; then
-			git clone [email protected]:draios/agent.git
+		if [ $PROBE_NAME != "sysdig-probe" ]; then
+		        update_code_for falco
 		fi
 
-		cd sysdig
-		git checkout master
-		# The UEK builder container doesn't have git credentials
-		# It relies on the non-UEK builds doing the pull earlier
-		if [[ ! "$KERNEL_TYPE" =~ "UEK" ]]; then
-			git pull
+		if [ $PROBE_NAME = "sysdigcloud-probe" ]; then
+		        update_code_for agent
 		fi
-		git checkout agent/$PROBE_VERSION
-		make -C driver clean || true
-		rm -rf build || true
-		cd ..
 
-		cd falco
-		git checkout master
-		if [[ ! "$KERNEL_TYPE" =~ "UEK" ]]; then
-			git pull
-		fi
-		git checkout agent/$PROBE_VERSION
-		rm -fr build || true
-		cd ..
-
-		cd agent
-		git checkout master
-		if [[ ! "$KERNEL_TYPE" =~ "UEK" ]]; then
-			git pull
-		fi
-		git checkout $PROBE_VERSION
-		rm -rf build || true
+		cd $PROBE_REPO_NAME
 		mkdir build
 		cd build
-		cmake -DCMAKE_BUILD_TYPE=Release -DAGENT_VERSION=$PROBE_VERSION ..
+		version_name=-D$(echo $PROBE_REPO_NAME | tr [a-z] [A-Z])_VERSION
+
+		cmake -DCMAKE_BUILD_TYPE=Release $version_name=$PROBE_VERSION ..
 		make driver
 		strip -g driver/$PROBE_NAME.ko
 

scripts/sysdig-probe-loader

@@ -46,8 +46,12 @@ elif [ "$SCRIPT_NAME" = "sysdigcloud-probe-loader" ]; then
 	SYSDIG_VERSION=$(/opt/draios/bin/dragent --version)
 	PROBE_NAME="sysdigcloud-probe"
 	PACKAGE_NAME="draios-agent"
+elif [ "$SCRIPT_NAME" = "falco-probe-loader" ]; then
+	SYSDIG_VERSION=$(falco --version | cut -d' ' -f3)
+	PROBE_NAME="falco-probe"
+	PACKAGE_NAME="falco"
 else
-	echo "This script must be called as sysdig-probe-loader or sysdigcloud-probe-loader"
+	echo "This script must be called as sysdig-probe-loader, sysdigcloud-probe-loader, or falco-probe-loader"
 	exit 1
 fi