[Qemu-devel] [PATCH for-3.0 ?] tests/libqtest: Improve kill_qemu() assert

[Peter Maydell <peter.maydell@linaro.org>]

In kill_qemu() we have an assert that checks that the QEMU process
didn't dump core:
            assert(!WCOREDUMP(wstatus));

Unfortunately the WCOREDUMP macro here means the resulting message
is not very easy to comprehend on at least some systems:

ahci-test: tests/libqtest.c:113: kill_qemu: Assertion `!(((__extension__ (((union { __typeof(wstatus) __in; int __i; }) { .__in = (wstatus) }).__i))) & 0x80)' failed.

and it doesn't identify what signal the process took.

Instead of using a raw assert, print the information in an
easier to understand way:

/i386/ahci/sanity: libqtest.c: kill_qemu() tried to terminate QEMU process but it dumped core with signal 11
ahci-test: tests/libqtest.c:118: kill_qemu: Assertion `0' failed.
Aborted (core dumped)

(Of course, the really useful information would be why the QEMU
process dumped core in the first place, but we don't have that
by the time the test program has picked up the exit status.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
In particular, the travis test config that enables gprof
seems to (a) run into this every so often and (b) have the
really unhelpful assertion text quoted above:
 https://travis-ci.org/qemu/qemu/jobs/406192798

Maybe for 3.0 since it's only test code.

 tests/libqtest.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tests/libqtest.c b/tests/libqtest.c
index 098af6aec44..99341e1b47d 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -110,7 +110,13 @@ static void kill_qemu(QTestState *s)
         pid = waitpid(s->qemu_pid, &wstatus, 0);
 
         if (pid == s->qemu_pid && WIFSIGNALED(wstatus)) {
-            assert(!WCOREDUMP(wstatus));
+            if (WCOREDUMP(wstatus)) {
+                fprintf(stderr,
+                        "libqtest.c: kill_qemu() tried to terminate QEMU "
+                        "process but it dumped core with signal %d\n",
+                        WTERMSIG(wstatus));
+                assert(0);
+            }
         }
     }
 }
-- 
2.17.1