regression sysctl: skip if sysctl not available

Some kernels have CONFIG_SYSCALL_SYSCTL disabled, which is something to
be encouraged. This patch separates out the two different kind of sysctl
tests (syscall based and /proc/sys based) into separate shell functions,
and then checks to see that the test environment supports each before
invoking each shell function, issuing a warning (but not failing the
tests) if not available.

Signed-off-by: Steve Beattie <steve@nxnw.org>
Acked-by: John Johansen <john.johansen@canonical.com>

tests/regression/apparmor/syscall_sysctl.sh

@@ -25,6 +25,9 @@ bin=$pwd
 ##
 ## C. SYSCTL
 ##
+
+test_syscall_sysctl()
+{
     settest syscall_sysctl
 
     runchecktest "SYSCTL (no confinement read only)" pass ro
@@ -66,9 +69,10 @@ runchecktest "SYSCTL (confinement/bad r w/ rw perm)" fail ro
 
     genprofile $sysctlbad:rw
     runchecktest "SYSCTL (confinement/bad rw w/ rw perm)" fail
+}
 
-# now test /proc/sys/ paths
-
+test_sysctl_proc()
+{
     settest sysctl_proc
 
     #unconfined
@@ -138,6 +142,23 @@ runchecktest "SYSCTL /proc (confinement/bad rw w/ w perm)" fail $sysctlgood rw
 
     genprofile $sysctlbad:rw
     runchecktest "SYSCTL /proc (confinement/bad rw w/ rw perm)" fail $sysctlgood rw
+}
 
 
+# check if the kernel supports CONFIG_SYSCTL_SYSCALL
+# generally we want to encourage kernels to disable it, but if it's
+# enabled we want to test against it
+settest syscall_sysctl
+res=$(${test} ro)
+if [ $? -ne 0 -a $res == "FAIL: sysctl read failed - Function not implemented" ] ; then
+    echo "	WARNING: syscall sysctl not implemented, skipping tests ..."
+else
+    test_syscall_sysctl
+fi
 
+# now test /proc/sys/ paths
+if [ ! -f "${sysctlgood}" ] ; then
+    echo "	WARNING: proc sysctl path not found, /proc not mounted? Skipping tests ..."
+else
+    test_sysctl_proc
+fi