[Xen-devel] [PATCH v2] libvchan: handle libxc evtchn failures properly in init functions

[Matthew Daley <mattjd@xxxxxxxxx>]

The reasoning behind this patch is that ctrl->event_port is a uint32_t
(ie. unsigned), so the current checks on it for negative error results,
non-negative port presence etc. are incorrect.

Fix by using evtchn_port_or_error_t in the init functions instead,
adjusting the error handling, and removing the now-unnecessary check
from the close function.

Coverity-ID: 1055609
Coverity-ID: 1055610
Coverity-ID: 1055611
Signed-off-by: Matthew Daley <mattjd@xxxxxxxxx>
Reviewed-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
v2: Elaborate patch purpose in commit message. Change from int to
evtchn_port_or_error_t, suggested by Daniel De Graaf.

 tools/libvchan/init.c |   47 +++++++++++++++++++++++++++++++++++++++--------
 tools/libvchan/io.c   |    2 +-
 2 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/tools/libvchan/init.c b/tools/libvchan/init.c
index 0c7cff6..c080a1c 100644
--- a/tools/libvchan/init.c
+++ b/tools/libvchan/init.c
@@ -215,15 +215,30 @@ static int init_gnt_cli(struct libxenvchan *ctrl, int 
domain, uint32_t ring_ref)
 
 static int init_evt_srv(struct libxenvchan *ctrl, int domain, 
xentoollog_logger *logger)
 {
+       evtchn_port_or_error_t port;
+
        ctrl->event = xc_evtchn_open(logger, 0);
        if (!ctrl->event)
                return -1;
-       ctrl->event_port = xc_evtchn_bind_unbound_port(ctrl->event, domain);
-       if (ctrl->event_port < 0)
-               return -1;
+
+       port = xc_evtchn_bind_unbound_port(ctrl->event, domain);
+       if (port < 0)
+               goto fail;
+       ctrl->event_port = port;
+
        if (xc_evtchn_unmask(ctrl->event, ctrl->event_port))
-               return -1;
+               goto fail;
+
        return 0;
+
+fail:
+       if (port >= 0)
+               xc_evtchn_unbind(ctrl->event, port);
+
+       xc_evtchn_close(ctrl->event);
+       ctrl->event = NULL;
+
+       return -1;
 }
 
 static int init_xs_srv(struct libxenvchan *ctrl, int domain, const char* 
xs_base, int ring_ref)
@@ -330,15 +345,31 @@ out:
 
 static int init_evt_cli(struct libxenvchan *ctrl, int domain, 
xentoollog_logger *logger)
 {
+       evtchn_port_or_error_t port;
+
        ctrl->event = xc_evtchn_open(logger, 0);
        if (!ctrl->event)
                return -1;
-       ctrl->event_port = xc_evtchn_bind_interdomain(ctrl->event,
+
+       port = xc_evtchn_bind_interdomain(ctrl->event,
                domain, ctrl->event_port);
-       if (ctrl->event_port < 0)
-               return -1;
-       xc_evtchn_unmask(ctrl->event, ctrl->event_port);
+       if (port < 0)
+               goto fail;
+       ctrl->event_port = port;
+
+       if (xc_evtchn_unmask(ctrl->event, ctrl->event_port))
+               goto fail;
+
        return 0;
+
+fail:
+       if (port >= 0)
+               xc_evtchn_unbind(ctrl->event, port);
+
+       xc_evtchn_close(ctrl->event);
+       ctrl->event = NULL;
+
+       return -1;
 }
 
 
diff --git a/tools/libvchan/io.c b/tools/libvchan/io.c
index 3c8d236..2383364 100644
--- a/tools/libvchan/io.c
+++ b/tools/libvchan/io.c
@@ -337,7 +337,7 @@ void libxenvchan_close(struct libxenvchan *ctrl)
                }
        }
        if (ctrl->event) {
-               if (ctrl->event_port >= 0 && ctrl->ring)
+               if (ctrl->ring)
                        xc_evtchn_notify(ctrl->event, ctrl->event_port);
                xc_evtchn_close(ctrl->event);
        }
-- 
1.7.10.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel