tests/vm: Allow to set qemu-img path

By default VM build test use qemu-img from system's PATH to
create the image disk. Due the lack of qemu-img on the system
or the desire to simply use a version built with QEMU, it would
be nice to allow one to set its path. So this patch makes that
possible by reading the path to qemu-img from QEMU_IMG if set,
otherwise it fallback to default behavior.

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-Id: <20191114134246.12073-2-wainersm@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

docs/devel/testing.rst

@@ -418,13 +418,15 @@ access, so they SHOULD NOT be exposed to external interfaces if you are
 concerned about attackers taking control of the guest and potentially
 exploiting a QEMU security bug to compromise the host.
 
-QEMU binary
+QEMU binaries
------------
+-------------
 
 By default, qemu-system-x86_64 is searched in $PATH to run the guest. If there
 isn't one, or if it is older than 2.10, the test won't work. In this case,
 provide the QEMU binary in env var: ``QEMU=/path/to/qemu-2.10+``.
 
+Likewise the path to qemu-img can be set in QEMU_IMG environment variable.
+
 Make jobs
 ---------
 

tests/vm/Makefile.include

@@ -34,6 +34,7 @@ vm-help vm-test:
 	@echo "    DEBUG=1              	 - Enable verbose output on host and interactive debugging"
 	@echo "    V=1				 - Enable verbose ouput on host and guest commands"
 	@echo "    QEMU=/path/to/qemu		 - Change path to QEMU binary"
+	@echo "    QEMU_IMG=/path/to/qemu-img	 - Change path to qemu-img tool"
 
 vm-build-all: $(addprefix vm-build-, $(IMAGES))
 

tests/vm/basevm.py

@@ -152,6 +152,11 @@ class BaseVM(object):
     def build_image(self, img):
         raise NotImplementedError
 
+    def exec_qemu_img(self, *args):
+        cmd = [os.environ.get("QEMU_IMG", "qemu-img")]
+        cmd.extend(list(args))
+        subprocess.check_call(cmd)
+
     def add_source_dir(self, src_dir):
         name = "data-" + hashlib.sha1(src_dir.encode("utf-8")).hexdigest()[:5]
         tarfile = os.path.join(self._tmpdir, name + ".tar")

tests/vm/centos

@@ -68,7 +68,7 @@ class CentosVM(basevm.BaseVM):
         sys.stderr.write("Extracting the image...\n")
         subprocess.check_call(["ln", "-f", cimg, img_tmp + ".xz"])
         subprocess.check_call(["xz", "--keep", "-dvf", img_tmp + ".xz"])
-        subprocess.check_call(["qemu-img", "resize", img_tmp, "50G"])
+        self.exec_qemu_img("resize", img_tmp, "50G")
         self.boot(img_tmp, extra_args = ["-cdrom", self._gen_cloud_init_iso()])
         self.wait_ssh()
         self.ssh_root_check("touch /etc/cloud/cloud-init.disabled")

tests/vm/fedora

@@ -74,9 +74,7 @@ class FedoraVM(basevm.BaseVM):
 
         self.print_step("Preparing iso and disk image")
         subprocess.check_call(["cp", "-f", cimg, iso])
-        subprocess.check_call(["qemu-img", "create", "-f", "qcow2",
+        self.exec_qemu_img("create", "-f", "qcow2", img_tmp, self.size)
-                               img_tmp, self.size])
-
         self.print_step("Booting installer")
         self.boot(img_tmp, extra_args = [
             "-bios", "pc-bios/bios-256k.bin",

tests/vm/freebsd

@@ -82,8 +82,7 @@ class FreeBSDVM(basevm.BaseVM):
         self.print_step("Preparing iso and disk image")
         subprocess.check_call(["cp", "-f", cimg, iso_xz])
         subprocess.check_call(["xz", "-dvf", iso_xz])
-        subprocess.check_call(["qemu-img", "create", "-f", "qcow2",
+        self.exec_qemu_img("create", "-f", "qcow2", img_tmp, self.size)
-                               img_tmp, self.size])
 
         self.print_step("Booting installer")
         self.boot(img_tmp, extra_args = [

tests/vm/netbsd

@@ -77,8 +77,7 @@ class NetBSDVM(basevm.BaseVM):
 
         self.print_step("Preparing iso and disk image")
         subprocess.check_call(["ln", "-f", cimg, iso])
-        subprocess.check_call(["qemu-img", "create", "-f", "qcow2",
+        self.exec_qemu_img("create", "-f", "qcow2", img_tmp, self.size)
-                               img_tmp, self.size])
 
         self.print_step("Booting installer")
         self.boot(img_tmp, extra_args = [

tests/vm/openbsd

@@ -73,8 +73,7 @@ class OpenBSDVM(basevm.BaseVM):
 
         self.print_step("Preparing iso and disk image")
         subprocess.check_call(["cp", "-f", cimg, iso])
-        subprocess.check_call(["qemu-img", "create", "-f", "qcow2",
+        self.exec_qemu_img("create", "-f", "qcow2", img_tmp, self.size)
-                               img_tmp, self.size])
 
         self.print_step("Booting installer")
         self.boot(img_tmp, extra_args = [

tests/vm/ubuntu.i386

@@ -70,7 +70,7 @@ class UbuntuX86VM(basevm.BaseVM):
             sha256sum="28969840626d1ea80bb249c08eef1a4533e8904aa51a327b40f37ac4b4ff04ef")
         img_tmp = img + ".tmp"
         subprocess.check_call(["cp", "-f", cimg, img_tmp])
-        subprocess.check_call(["qemu-img", "resize", img_tmp, "50G"])
+        self.exec_qemu_img("resize", img_tmp, "50G")
         self.boot(img_tmp, extra_args = ["-cdrom", self._gen_cloud_init_iso()])
         self.wait_ssh()
         self.ssh_root_check("touch /etc/cloud/cloud-init.disabled")