[PATCH synaptics 3/6] eventcomm: Hook up the libevdev log handler

[Peter Hutterer]

This is a bit problematic: libevdev only has one global log handler.
So if we have another driver use libevdev, we'll either overwrite that handler
or get overwritten, whichever comes first. So we need to re-set the handler
every time we get an event to make sure we log through our handler.
Likewise, if we ever drop the device, we need to unset the log handler back to
NULL because we may unload the module and our handler may disappear.

Use the lowest logging priority, let the server filter based on the verbosity
level instead.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/eventcomm.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/src/eventcomm.c b/src/eventcomm.c
index 0cbbbd0..5871374 100644
--- a/src/eventcomm.c
+++ b/src/eventcomm.c
@@ -87,12 +87,46 @@ struct eventcomm_proto_data {
     enum libevdev_read_flag read_flag;
 };
 
+static void
+libevdev_log_func(enum libevdev_log_priority priority,
+                  void *data,
+                  const char *file, int line, const char *func,
+                  const char *format, va_list args)
+_X_ATTRIBUTE_PRINTF(6, 0);
+
+static void
+libevdev_log_func(enum libevdev_log_priority priority,
+                  void *data,
+                  const char *file, int line, const char *func,
+                  const char *format, va_list args)
+{
+    int verbosity;
+
+    switch(priority) {
+        case LIBEVDEV_LOG_ERROR: verbosity = 0; break;
+        case LIBEVDEV_LOG_INFO: verbosity = 4; break;
+        case LIBEVDEV_LOG_DEBUG: verbosity = 10; break;
+    }
+
+    LogVMessageVerbSigSafe(X_NOTICE, verbosity, format, args);
+}
+
+static void
+set_libevdev_log_handler(void)
+{
+                              /* be quiet, gcc *handwave* */
+    libevdev_set_log_function((libevdev_log_func_t)libevdev_log_func, NULL);
+    libevdev_set_log_priority(LIBEVDEV_LOG_DEBUG);
+}
+
 struct eventcomm_proto_data *
 EventProtoDataAlloc(int fd)
 {
     struct eventcomm_proto_data *proto_data;
     int rc;
 
+    set_libevdev_log_handler();
+
     proto_data = calloc(1, sizeof(struct eventcomm_proto_data));
     if (!proto_data)
         return NULL;
@@ -181,6 +215,8 @@ EventDeviceOnHook(InputInfoPtr pInfo, SynapticsParameters * para)
     struct eventcomm_proto_data *proto_data =
         (struct eventcomm_proto_data *) priv->proto_data;
 
+    set_libevdev_log_handler();
+
     if (libevdev_get_fd(proto_data->evdev) != -1) {
         struct input_event ev;
 
@@ -224,6 +260,8 @@ EventDeviceOffHook(InputInfoPtr pInfo)
 
     UninitializeTouch(pInfo);
     libevdev_grab(proto_data->evdev, LIBEVDEV_UNGRAB);
+    libevdev_set_log_function(NULL, NULL);
+    libevdev_set_log_priority(LIBEVDEV_LOG_INFO); /* reset to default */
 
     return Success;
 }
@@ -625,6 +663,8 @@ EventReadHwState(InputInfoPtr pInfo,
     struct eventcomm_proto_data *proto_data = priv->proto_data;
     Bool sync_cumulative = FALSE;
 
+    set_libevdev_log_handler();
+
     SynapticsResetTouchHwState(hw, FALSE);
 
     /* Reset cumulative values if buttons were not previously pressed,
-- 
1.9.0