Adding losetup utility package to core pkg

Signed-off-by: Christian Wuerdig <christian.wuerdig@gmail.com>

test/cases/040_packages/012_losetup/check.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+function failed {
+	printf "losetup test suite FAILED\n" >&1
+	exit 1
+}
+
+LOOPFILE=$(losetup /dev/loop0 2>/dev/null | cut -d' ' -f3)
+
+[ "$LOOPFILE" = "/var/test.img" ] || failed
+
+printf "losetup test suite PASSED\n" >&1

test/cases/040_packages/012_losetup/test.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+# SUMMARY: Check that the losetup package works
+# LABELS:
+# REPEAT:
+
+set -e
+
+# Source libraries. Uncomment if needed/defined
+#. "${RT_LIB}"
+. "${RT_PROJECT_ROOT}/_lib/lib.sh"
+
+NAME=losetup
+
+clean_up() {
+	rm -rf ${NAME}-*
+}
+trap clean_up EXIT
+
+# Test code goes here
+linuxkit build -format kernel+initrd -name "${NAME}" test.yml
+RESULT="$(linuxkit run $NAME)"
+echo "${RESULT}"
+echo "${RESULT}" | grep -q "suite PASSED"
+
+exit 0

test/cases/040_packages/012_losetup/test.yml

@@ -0,0 +1,28 @@
+kernel:
+  image: linuxkit/kernel:4.14.88
+  cmdline: "console=ttyS0 console=ttyAMA0"
+init:
+  - linuxkit/init:c563953a2277eb73a89d89f70e4b6dcdcfebc2d1
+  - linuxkit/runc:83d0edb4552b1a5df1f0976f05f442829eac38fe
+onboot:
+  - name: losetup
+    image: linuxkit/losetup:aaceeea49ac519bc3b87da239436dd997d67b431
+    command: ["/usr/bin/loopy", "-c", "/var/test.img"]
+  - name: test
+    image: alpine:3.8
+    net: host
+    binds:
+      - /check.sh:/check.sh
+      - /dev:/dev
+    command: ["sh", "./check.sh"]
+  - name: poweroff
+    image: linuxkit/poweroff:afe8f7dd0d47a7991c54519b0f09124cb8c4e300
+    command: ["/bin/sh", "/poweroff.sh", "10"]
+files:
+  - path: check.sh
+    source: ./check.sh
+trust:
+  org:
+    - linuxkit
+  image:
+    - alpine:3.8