libxl: events: timedereg internal unit test

Test timeout deregistration idempotency.  In the current tree this
test fails because ev->func is not cleared, meaning that a timeout
can be removed from the list more than once, corrupting the list.

It is necessary to use multiple timeouts to demonstrate this bug,
because removing the very same entry twice from a list in quick
succession, without modifying the list in other ways in between,
doesn't actually corrupt the list.  (Since removing an entry from a
doubly-linked list just copies next and back from the disappearing
entry into its neighbours.)

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Jim Fehlig <jfehlig@suse.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>

diff --git a/.gitignore b/.gitignore
index 3504584c89eb9bd56e076bb6bba856e227daa009..db3b0831cb376f164047bd9d0385c66415dccdad 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -361,6 +361,7 @@ tools/libxl/testidl
 tools/libxl/testidl.c
 tools/libxl/*.pyc
 tools/libxl/libxl-save-helper
+tools/libxl/test_timedereg
 tools/blktap2/control/tap-ctl
 tools/firmware/etherboot/eb-roms.h
 tools/firmware/etherboot/gpxe-git-snapshot.tar.gz

diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index cc21247fe7900b4f677996728fd404c2710db3c2..66f3f3f7f119885d5b837f1f7909e53128c75668 100644 (file)
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -79,7 +79,7 @@ LIBXL_OBJS = flexarray.o libxl.o libxl_create.o libxl_dm.o libxl_pci.o \
                        libxl_qmp.o libxl_event.o libxl_fork.o $(LIBXL_OBJS-y)
 LIBXL_OBJS += _libxl_types.o libxl_flask.o _libxl_types_internal.o
 
-LIBXL_TESTS +=
+LIBXL_TESTS += timedereg
 # Each entry FOO in LIBXL_TESTS has two main .c files:
 #   libxl_test_FOO.c  "inside libxl" code to support the test case
 #   test_FOO.c        "outside libxl" code to exercise the test case

diff --git a/tools/libxl/libxl_test_timedereg.c b/tools/libxl/libxl_test_timedereg.c
new file mode 100644 (file)
index 0000000..a44639f
--- /dev/null
+++ b/tools/libxl/libxl_test_timedereg.c
@@ -0,0 +1,97 @@
+/*
+ * timedereg test case for the libxl event system
+ *
+ * To run this test:
+ *    ./test_timedereg
+ * Success:
+ *    program takes a few seconds, prints some debugging output and exits 0
+ * Failure:
+ *    crash
+ *
+ * set up [0]-group timeouts 0 1 2
+ * wait for timeout 1 to occur
+ * deregister 0 and 2.  1 is supposed to be deregistered already
+ * register [1]-group 0 1 2
+ * deregister 1 (should be a no-op)
+ * wait for [1]-group 0 1 2 in turn
+ * on final callback assert that all have been deregistered
+ */
+
+#include "libxl_internal.h"
+
+#include "libxl_test_timedereg.h"
+
+#define NTIMES 3
+static const int ms[2][NTIMES] = { { 2000,1000,2000 }, { 1000,2000,3000 } };
+static libxl__ev_time et[2][NTIMES];
+static libxl__ao *tao;
+static int seq;
+
+static void occurs(libxl__egc *egc, libxl__ev_time *ev,
+                   const struct timeval *requested_abs);
+
+static void regs(libxl__gc *gc, int j)
+{
+    int rc, i;
+    LOG(DEBUG,"regs(%d)", j);
+    for (i=0; i<NTIMES; i++) {
+        rc = libxl__ev_time_register_rel(gc, &et[j][i], occurs, ms[j][i]);
+        assert(!rc);
+    }    
+}
+
+int libxl_test_timedereg(libxl_ctx *ctx, libxl_asyncop_how *ao_how)
+{
+    int i;
+    AO_CREATE(ctx, 0, ao_how);
+
+    tao = ao;
+
+    for (i=0; i<NTIMES; i++) {
+        libxl__ev_time_init(&et[0][i]);
+        libxl__ev_time_init(&et[1][i]);
+    }
+
+    regs(gc, 0);
+
+    return AO_INPROGRESS;
+}
+
+static void occurs(libxl__egc *egc, libxl__ev_time *ev,
+                   const struct timeval *requested_abs)
+{
+    EGC_GC;
+    int i;
+
+    int off = ev - &et[0][0];
+    LOG(DEBUG,"occurs[%d][%d] seq=%d", off/NTIMES, off%NTIMES, seq);
+
+    switch (seq) {
+    case 0:
+        assert(ev == &et[0][1]);
+        libxl__ev_time_deregister(gc, &et[0][0]);
+        libxl__ev_time_deregister(gc, &et[0][2]);
+        regs(gc, 1);
+        libxl__ev_time_deregister(gc, &et[0][1]);
+        break;
+
+    case 1:
+    case 2:
+        assert(ev == &et[1][seq-1]);
+        break;
+        
+    case 3:
+        assert(ev == &et[1][2]);
+        for (i=0; i<NTIMES; i++) {
+            assert(!libxl__ev_time_isregistered(&et[0][i]));
+            assert(!libxl__ev_time_isregistered(&et[1][i]));
+        }
+        libxl__ao_complete(egc, tao, 0);
+        return;
+
+    default:
+        abort();
+    }
+
+    seq++;
+}

diff --git a/tools/libxl/libxl_test_timedereg.h b/tools/libxl/libxl_test_timedereg.h
new file mode 100644 (file)
index 0000000..9547dba
--- /dev/null
+++ b/tools/libxl/libxl_test_timedereg.h
@@ -0,0 +1,9 @@
+#ifndef TEST_TIMEDEREG_H
+#define TEST_TIMEDEREG_H
+
+#include <pthread.h>
+
+int libxl_test_timedereg(libxl_ctx *ctx, libxl_asyncop_how *ao_how)
+    LIBXL_EXTERNAL_CALLERS_ONLY;
+
+#endif /*TEST_TIMEDEREG_H*/

diff --git a/tools/libxl/test_timedereg.c b/tools/libxl/test_timedereg.c
new file mode 100644 (file)
index 0000000..0081ce3
--- /dev/null
+++ b/tools/libxl/test_timedereg.c
@@ -0,0 +1,11 @@
+#include "test_common.h"
+#include "libxl_test_timedereg.h"
+
+int main(int argc, char **argv) {
+    int rc;
+
+    test_common_setup(XTL_DEBUG);
+
+    rc = libxl_test_timedereg(ctx, 0);
+    assert(!rc);
+}