Log anything that could prevent a daemon from starting.

[sliver-openvswitch.git] / lib / vlog.h

diff --git a/lib/vlog.h b/lib/vlog.h
index 03f17ea..1feab45 100644 (file)
--- a/lib/vlog.h
+++ b/lib/vlog.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,27 @@
 extern "C" {
 #endif
 
-/* Logging importance levels. */
+/* Logging importance levels.
+ *
+ * The following log levels, in descending order of importance, are enabled by
+ * default:
+ *
+ *   - EMER: Not currently used.
+ *
+ *   - ERR: A high-level operation or a subsystem failed.  Attention is
+ *     warranted.
+ *
+ *   - WARN: A low-level operation failed, but higher-level subsystems may be
+ *     able to recover.
+ *
+ *   - INFO: Information that may be useful in retrospect when investigating
+ *     a problem.
+ *
+ * The lowest log level is not enabled by default:
+ *
+ *   - DBG: Information useful only to someone with intricate knowledge of the
+ *     system, or that would commonly cause too-voluminous log output.
+ */
 #define VLOG_LEVELS                             \
     VLOG_LEVEL(EMER, LOG_ALERT)                 \
     VLOG_LEVEL(ERR, LOG_ERR)                    \
@@ -72,9 +92,9 @@ struct vlog_module {
 #define VLOG_DEFINE_MODULE(MODULE)                                      \
         VLOG_DEFINE_MODULE__(MODULE)                                    \
         struct vlog_module *vlog_module_ptr_##MODULE                    \
-            __attribute__((section("vlog_modules"))) = &VLM_##MODULE;
+            __attribute__((section("vlog_modules"))) = &VLM_##MODULE
 #else
-#define VLOG_DEFINE_MODULE(MODULE) extern struct vlog_module VLM_##MODULE;
+#define VLOG_DEFINE_MODULE(MODULE) extern struct vlog_module VLM_##MODULE
 #endif
 
 const char *vlog_get_module_name(const struct vlog_module *);
@@ -128,14 +148,24 @@ const char *vlog_get_log_file(void);
 int vlog_set_log_file(const char *file_name);
 int vlog_reopen_log_file(void);
 
-/* Function for actual logging. */
+/* Initialization. */
 void vlog_init(void);
 void vlog_exit(void);
+
+/* Functions for actual logging. */
 void vlog(const struct vlog_module *, enum vlog_level, const char *format, ...)
     __attribute__((format(printf, 3, 4)));
 void vlog_valist(const struct vlog_module *, enum vlog_level,
                  const char *, va_list)
     __attribute__((format(printf, 3, 0)));
+
+void vlog_fatal(const struct vlog_module *, enum vlog_level,
+                const char *format, ...)
+    PRINTF_FORMAT (3, 4) NO_RETURN;
+void vlog_fatal_valist(const struct vlog_module *, enum vlog_level,
+                       const char *, va_list)
+    PRINTF_FORMAT (3, 0) NO_RETURN;
+
 void vlog_rate_limit(const struct vlog_module *, enum vlog_level,
                      struct vlog_rate_limit *, const char *, ...)
     __attribute__((format(printf, 4, 5)));
@@ -144,8 +174,8 @@ void vlog_rate_limit(const struct vlog_module *, enum vlog_level,
  * defines a static variable named THIS_MODULE that points to it, for use with
  * the convenience macros below. */
 #define VLOG_DEFINE_THIS_MODULE(MODULE)                                 \
-        VLOG_DEFINE_MODULE(MODULE)                                      \
-        static struct vlog_module *const THIS_MODULE = &VLM_##MODULE;
+        VLOG_DEFINE_MODULE(MODULE);                                     \
+        static struct vlog_module *const THIS_MODULE = &VLM_##MODULE
 
 /* Convenience macros.  These assume that THIS_MODULE points to a "struct
  * vlog_module" for the current module, as set up by e.g. the
@@ -153,6 +183,7 @@ void vlog_rate_limit(const struct vlog_module *, enum vlog_level,
  *
  * Guaranteed to preserve errno.
  */
+#define VLOG_FATAL(...) vlog_fatal(THIS_MODULE, VLL_ERR, __VA_ARGS__)
 #define VLOG_EMER(...) VLOG(VLL_EMER, __VA_ARGS__)
 #define VLOG_ERR(...) VLOG(VLL_ERR, __VA_ARGS__)
 #define VLOG_WARN(...) VLOG(VLL_WARN, __VA_ARGS__)
@@ -181,6 +212,12 @@ void vlog_rate_limit(const struct vlog_module *, enum vlog_level,
 #define VLOG_DROP_INFO(RL) vlog_should_drop(THIS_MODULE, VLL_INFO, RL)
 #define VLOG_DROP_DBG(RL) vlog_should_drop(THIS_MODULE, VLL_DBG, RL)
 
+/* Macros for logging at most once per execution. */
+#define VLOG_ERR_ONCE(...) VLOG_ONCE(VLL_ERR, __VA_ARGS__)
+#define VLOG_WARN_ONCE(...) VLOG_ONCE(VLL_WARN, __VA_ARGS__)
+#define VLOG_INFO_ONCE(...) VLOG_ONCE(VLL_INFO, __VA_ARGS__)
+#define VLOG_DBG_ONCE(...) VLOG_ONCE(VLL_DBG, __VA_ARGS__)
+
 /* Command line processing. */
 #define VLOG_OPTION_ENUMS OPT_LOG_FILE
 #define VLOG_LONG_OPTIONS                                   \
@@ -208,6 +245,15 @@ void vlog_usage(void);
             vlog_rate_limit(THIS_MODULE, LEVEL, RL, __VA_ARGS__);   \
         }                                                           \
     } while (0)
+#define VLOG_ONCE(LEVEL, ...)                       \
+    do {                                            \
+        static bool already_logged;                 \
+        if (!already_logged) {                      \
+            already_logged = true;                  \
+            vlog(THIS_MODULE, LEVEL, __VA_ARGS__);  \
+        }                                           \
+    } while (0)
+
 #define VLOG_DEFINE_MODULE__(MODULE)                                    \
         struct vlog_module VLM_##MODULE =                               \
         {                                                               \