udev: fix crash in libudev logging

Call virLogVMessage instead of virLogMessage, since libudev
called us with a va_list object, not a list of arguments.

Honor message priority and strip the trailing newline.

https://bugzilla.redhat.com/show_bug.cgi?id=969152
(cherry picked from commit f753dd62)

Conflicts:
	src/libvirt_private.syms
	src/node_device/node_device_udev.c
	src/util/logging.c
	src/util/logging.h

src/libvirt_private.syms

@@ -809,11 +809,13 @@ virLogMessage;
 virLogParseDefaultPriority;
 virLogParseFilters;
 virLogParseOutputs;
+virLogPriorityFromSyslog;
 virLogReset;
 virLogSetBufferSize;
 virLogSetDefaultPriority;
 virLogSetFromEnv;
 virLogUnlock;
+virLogVMessage;
 
 
 # memory.h

src/node_device/node_device_udev.c

@@ -350,15 +350,36 @@ static int udevGenerateDeviceName(struct udev_device *device,
 }
 
 
-static void udevLogFunction(struct udev *udev ATTRIBUTE_UNUSED,
-                            int priority ATTRIBUTE_UNUSED,
-                            const char *file,
-                            int line,
-                            const char *fn,
-                            const char *fmt,
-                            va_list args)
+typedef void (*udevLogFunctionPtr)(struct udev *udev,
+                                   int priority,
+                                   const char *file,
+                                   int line,
+                                   const char *fn,
+                                   const char *format,
+                                   va_list args);
+
+static void
+ATTRIBUTE_FMT_PRINTF(6,0)
+udevLogFunction(struct udev *udev ATTRIBUTE_UNUSED,
+                int priority,
+                const char *file,
+                int line,
+                const char *fn,
+                const char *fmt,
+                va_list args)
 {
-    VIR_ERROR_INT(file, fn, line, fmt, args);
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    const char *format = NULL;
+
+    virBufferAdd(&buf, fmt, -1);
+    virBufferTrim(&buf, "\n", -1);
+
+    format = virBufferContentAndReset(&buf);
+
+    virLogVMessage(file, virLogPriorityFromSyslog(priority),
+                   fn, line, 0, format ? format : fmt, args);
+
+    VIR_FREE(format);
 }
 
 
@@ -1662,7 +1683,8 @@ static int udevDeviceMonitorStartup(int privileged ATTRIBUTE_UNUSED)
      * its return value.
      */
     udev = udev_new();
-    udev_set_log_fn(udev, udevLogFunction);
+    /* cast to get rid of missing-format-attribute warning */
+    udev_set_log_fn(udev, (udevLogFunctionPtr) udevLogFunction);
 
     priv->udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
     if (priv->udev_monitor == NULL) {

src/util/logging.c

@@ -919,6 +919,31 @@ static int virLogAddOutputToSyslog(int priority, const char *ident) {
     }
     return 0;
 }
+
+int virLogPriorityFromSyslog(int priority)
+{
+    switch (priority) {
+    case LOG_EMERG:
+    case LOG_ALERT:
+    case LOG_CRIT:
+    case LOG_ERR:
+        return VIR_LOG_ERROR;
+    case LOG_WARNING:
+    case LOG_NOTICE:
+        return VIR_LOG_WARN;
+    case LOG_INFO:
+        return VIR_LOG_INFO;
+    case LOG_DEBUG:
+        return VIR_LOG_DEBUG;
+    }
+    return VIR_LOG_ERROR;
+}
+
+#else /* HAVE_SYSLOG_H */
+int virLogPriorityFromSyslog(int priority ATTRIBUTE_UNUSED)
+{
+    return VIR_LOG_ERROR;
+}
 #endif /* HAVE_SYSLOG_H */
 
 #define IS_SPACE(cur)                                                   \

src/util/logging.h

@@ -137,6 +137,7 @@ extern int virLogReset(void);
 extern int virLogParseDefaultPriority(const char *priority);
 extern int virLogParseFilters(const char *filters);
 extern int virLogParseOutputs(const char *output);
+extern int virLogPriorityFromSyslog(int priority);
 extern void virLogMessage(const char *category, int priority,
                           const char *funcname, long long linenr,
                           unsigned int flags,