test: Resolution logic for os-release

dkms.in

@@ -2325,7 +2325,7 @@ unset CC CXX CFLAGS CXXFLAGS LDFLAGS
 # Set important variables
 current_kernel=$(uname -r)
 current_os=$(uname -s)
-running_distribution=$(distro_version)
+running_distribution=$(distro_version) || exit
 dkms_tree="/var/lib/dkms"
 source_tree="/usr/src"
 install_tree="/lib/modules"

run_test.sh

@@ -29,6 +29,7 @@ TEST_MODULES=(
     "dkms_conf_test"
     "dkms_build_exclusive_test"
     "dkms_build_exclusive_dependencies_test"
+    "dkms_osrelease_stub"
 )
 TEST_TMPDIRS=(
     "/usr/src/dkms_test-1.0/"
@@ -44,6 +45,7 @@ TEST_TMPDIRS=(
     "/usr/src/dkms_conf_test-1.0"
     "/usr/src/dkms_build_exclusive_test-1.0"
     "/usr/src/dkms_build_exclusive_dependencies_test-1.0"
+    "/usr/src/dkms_osrelease_stub-1.0"
     "/tmp/dkms_test_dir_${KERNEL_VER}/"
 )
 TEST_TMPFILES=(
@@ -1541,6 +1543,54 @@ EOF
 echo 'Removing /usr/src/dkms_build_exclusive_test-1.0'
 rm -r /usr/src/dkms_build_exclusive_test-1.0
 
+############################################################################
+### Testing os-release detection                                         ###
+############################################################################
+# Get the contents of the os-release file. We do it first so symlinks resolve
+osrelease_contents=$(for f in /etc/os-release /usr/lib/os-release; do
+    cat "$f"
+done)
+osrelease_cleanup() {
+    mv _etc-os-release /etc/os-release &>/dev/null
+    mv _usrlib-os-release /usr/lib/os-release &>/dev/null
+}
+trap osrelease_cleanup EXIT
+mv /etc/os-release _etc-os-release &>/dev/null
+mv /usr/lib/os-release _usrlib-os-release &>/dev/null
+
+echo "Fails when there are no os-release files"
+run_with_expected_error 4 dkms add test/dkms_osrelease_stub-1.0 << EOF
+Error! System is missing os-release file.
+EOF
+
+cat > /etc/os-release <<< "$osrelease_contents"
+echo 'Reads /etc/os-release'
+run_with_expected_output dkms add test/dkms_osrelease_stub-1.0 << EOF
+Creating symlink /var/lib/dkms/dkms_osrelease_stub/1.0/source -> /usr/src/dkms_osrelease_stub-1.0
+EOF
+run_status_with_expected_output 'dkms_osrelease_stub' << EOF
+dkms_osrelease_stub/1.0: added
+EOF
+run_with_expected_output dkms remove dkms_osrelease_stub/1.0 << EOF
+Module dkms_osrelease_stub 1.0 is not installed for kernel 5.15.0-86-generic (x86_64). Skipping...
+Module dkms_osrelease_stub 1.0 is not built for kernel 5.15.0-86-generic (x86_64). Skipping...
+Deleting module dkms_osrelease_stub-1.0 completely from the DKMS tree.
+EOF
+rm -f /etc/os-release
+
+cat > /usr/lib/os-release <<< "$osrelease_contents"
+echo 'Reads /usr/lib/os-release'
+run_with_expected_output dkms add test/dkms_osrelease_stub-1.0 << EOF
+Creating symlink /var/lib/dkms/dkms_osrelease_stub/1.0/source -> /usr/src/dkms_osrelease_stub-1.0
+EOF
+run_status_with_expected_output 'dkms_osrelease_stub' << EOF
+dkms_osrelease_stub/1.0: added
+EOF
+rm -f /usr/lib/os-release
+
+osrelease_cleanup
+trap - EXIT
+
 echo 'Checking that the environment is clean again'
 check_no_dkms_test
 

test/dkms_osrelease_stub-1.0/Makefile

@@ -0,0 +1,7 @@
+obj-m += dkms_test.o
+
+all:
+	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
+
+clean:
+	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

test/dkms_osrelease_stub-1.0/dkms.conf

@@ -0,0 +1,7 @@
+PACKAGE_NAME="dkms_osrelease_stub"
+PACKAGE_VERSION="1.0"
+BUILT_MODULE_NAME="dkms_osrelease_stub"
+
+AUTOINSTALL="yes"
+
+DEST_MODULE_LOCATION="/kernel/extra"

test/dkms_osrelease_stub-1.0/dkms_test.c

@@ -0,0 +1,23 @@
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+
+#define  DKMS_TEST_VER "1.0"
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("A Simple dkms test module");
+
+static int __init dkms_test_init(void)
+{
+    printk(KERN_INFO "DKMS Test Module -%s Loaded\n",DKMS_TEST_VER);
+    return 0;
+}
+
+static void __exit dkms_test_cleanup(void)
+{
+    printk(KERN_INFO "Cleaning up after dkms test module.\n");
+}
+
+module_init(dkms_test_init);
+module_exit(dkms_test_cleanup);
+MODULE_VERSION(DKMS_TEST_VER);