X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fvlog.c;h=a7d9e48b9ddd9d7fef59c7854b946191f28910b8;hb=e0edde6fee279cdbbf3c179f5f50adaf0c7c7f1e;hp=5496f010e6bfeea5e1d7152d4e0f4381c2845343;hpb=d65349ea28bb67a0062a9b4b60ff97538206373b;p=sliver-openvswitch.git

diff --git a/lib/vlog.c b/lib/vlog.c
index 5496f010e..a7d9e48b9 100644
--- a/lib/vlog.c
+++ b/lib/vlog.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,6 +22,7 @@
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <syslog.h>
 #include <time.h>
@@ -29,11 +30,12 @@
 #include "dirs.h"
 #include "dynamic-string.h"
 #include "sat-math.h"
+#include "svec.h"
 #include "timeval.h"
 #include "unixctl.h"
 #include "util.h"
 
-#define THIS_MODULE VLM_vlog
+VLOG_DEFINE_THIS_MODULE(vlog);
 
 /* Name for each logging level. */
 static const char *level_names[VLL_N_LEVELS] = {
@@ -49,12 +51,24 @@ static int syslog_levels[VLL_N_LEVELS] = {
 #undef VLOG_LEVEL
 };
 
-/* Name for each logging module */
-static const char *module_names[VLM_N_MODULES] = { 
-#define VLOG_MODULE(NAME) #NAME,
+/* The log modules. */
+#if USE_LINKER_SECTIONS
+extern struct vlog_module *__start_vlog_modules[];
+extern struct vlog_module *__stop_vlog_modules[];
+#define vlog_modules __start_vlog_modules
+#define n_vlog_modules (__stop_vlog_modules - __start_vlog_modules)
+#else
+#define VLOG_MODULE VLOG_DEFINE_MODULE__
+#include "vlog-modules.def"
+#undef VLOG_MODULE
+
+struct vlog_module *vlog_modules[] = {
+#define VLOG_MODULE(NAME) &VLM_##NAME,
 #include "vlog-modules.def"
 #undef VLOG_MODULE
 };
+#define n_vlog_modules ARRAY_SIZE(vlog_modules)
+#endif
 
 /* Information about each facility. */
 struct facility {
@@ -68,21 +82,14 @@ static struct facility facilities[VLF_N_FACILITIES] = {
 #undef VLOG_FACILITY
 };
 
-/* Current log levels. */
-static int levels[VLM_N_MODULES][VLF_N_FACILITIES];
-
-/* For fast checking whether we're logging anything for a given module and
- * level.*/
-enum vlog_level min_vlog_levels[VLM_N_MODULES];
-
-/* Time at which vlog was initialized, in milliseconds. */
-static long long int boot_time;
-
 /* VLF_FILE configuration. */
 static char *log_file_name;
 static FILE *log_file;
 
-static void format_log_message(enum vlog_module, enum vlog_level,
+/* vlog initialized? */
+static bool vlog_inited;
+
+static void format_log_message(const struct vlog_module *, enum vlog_level,
                                enum vlog_facility, unsigned int msg_num,
                                const char *message, va_list, struct ds *)
     PRINTF_FORMAT(5, 0);
@@ -90,7 +97,7 @@ static void format_log_message(enum vlog_module, enum vlog_level,
 /* Searches the 'n_names' in 'names'.  Returns the index of a match for
  * 'target', or 'n_names' if no name matches. */
 static size_t
-search_name_array(const char *target, const char **names, size_t n_names) 
+search_name_array(const char *target, const char **names, size_t n_names)
 {
     size_t i;
 
@@ -114,14 +121,14 @@ vlog_get_level_name(enum vlog_level level)
 /* Returns the logging level with the given 'name', or VLL_N_LEVELS if 'name'
  * is not the name of a logging level. */
 enum vlog_level
-vlog_get_level_val(const char *name) 
+vlog_get_level_val(const char *name)
 {
     return search_name_array(name, level_names, ARRAY_SIZE(level_names));
 }
 
 /* Returns the name for logging facility 'facility'. */
 const char *
-vlog_get_facility_name(enum vlog_facility facility) 
+vlog_get_facility_name(enum vlog_facility facility)
 {
     assert(facility < VLF_N_FACILITIES);
     return facilities[facility].name;
@@ -130,7 +137,7 @@ vlog_get_facility_name(enum vlog_facility facility)
 /* Returns the logging facility named 'name', or VLF_N_FACILITIES if 'name' is
  * not the name of a logging facility. */
 enum vlog_facility
-vlog_get_facility_val(const char *name) 
+vlog_get_facility_val(const char *name)
 {
     size_t i;
 
@@ -143,65 +150,77 @@ vlog_get_facility_val(const char *name)
 }
 
 /* Returns the name for logging module 'module'. */
-const char *vlog_get_module_name(enum vlog_module module) 
+const char *
+vlog_get_module_name(const struct vlog_module *module)
 {
-    assert(module < VLM_N_MODULES);
-    return module_names[module];
+    return module->name;
 }
 
-/* Returns the logging module named 'name', or VLM_N_MODULES if 'name' is not
- * the name of a logging module. */
-enum vlog_module
-vlog_get_module_val(const char *name) 
+/* Returns the logging module named 'name', or NULL if 'name' is not the name
+ * of a logging module. */
+struct vlog_module *
+vlog_module_from_name(const char *name)
 {
-    return search_name_array(name, module_names, ARRAY_SIZE(module_names));
+    struct vlog_module **mp;
+
+    for (mp = vlog_modules; mp < &vlog_modules[n_vlog_modules]; mp++) {
+        if (!strcasecmp(name, (*mp)->name)) {
+            return *mp;
+        }
+    }
+    return NULL;
 }
 
 /* Returns the current logging level for the given 'module' and 'facility'. */
 enum vlog_level
-vlog_get_level(enum vlog_module module, enum vlog_facility facility) 
+vlog_get_level(const struct vlog_module *module, enum vlog_facility facility)
 {
-    assert(module < VLM_N_MODULES);
     assert(facility < VLF_N_FACILITIES);
-    return levels[module][facility];
+    return module->levels[facility];
 }
 
 static void
-update_min_level(enum vlog_module module)
+update_min_level(struct vlog_module *module)
 {
-    enum vlog_level min_level = VLL_EMER;
     enum vlog_facility facility;
 
+    module->min_level = VLL_OFF;
     for (facility = 0; facility < VLF_N_FACILITIES; facility++) {
         if (log_file || facility != VLF_FILE) {
-            min_level = MAX(min_level, levels[module][facility]); 
+            enum vlog_level level = module->levels[facility];
+            if (level > module->min_level) {
+                module->min_level = level;
+            }
         }
     }
-    min_vlog_levels[module] = min_level;
 }
 
 static void
-set_facility_level(enum vlog_facility facility, enum vlog_module module,
+set_facility_level(enum vlog_facility facility, struct vlog_module *module,
                    enum vlog_level level)
 {
     assert(facility >= 0 && facility < VLF_N_FACILITIES);
     assert(level < VLL_N_LEVELS);
 
-    if (module == VLM_ANY_MODULE) {
-        for (module = 0; module < VLM_N_MODULES; module++) {
-            levels[module][facility] = level;
-            update_min_level(module);
+    if (!module) {
+        struct vlog_module **mp;
+
+        for (mp = vlog_modules; mp < &vlog_modules[n_vlog_modules]; mp++) {
+            (*mp)->levels[facility] = level;
+            update_min_level(*mp);
         }
     } else {
-        levels[module][facility] = level;
+        module->levels[facility] = level;
         update_min_level(module);
     }
 }
 
-/* Sets the logging level for the given 'module' and 'facility' to 'level'. */
+/* Sets the logging level for the given 'module' and 'facility' to 'level'.  A
+ * null 'module' or a 'facility' of VLF_ANY_FACILITY is treated as a wildcard
+ * across all modules or facilities, respectively. */
 void
-vlog_set_levels(enum vlog_module module, enum vlog_facility facility,
-                enum vlog_level level) 
+vlog_set_levels(struct vlog_module *module, enum vlog_facility facility,
+                enum vlog_level level)
 {
     assert(facility < VLF_N_FACILITIES || facility == VLF_ANY_FACILITY);
     if (facility == VLF_ANY_FACILITY) {
@@ -214,7 +233,7 @@ vlog_set_levels(enum vlog_module module, enum vlog_facility facility,
 }
 
 static void
-do_set_pattern(enum vlog_facility facility, const char *pattern) 
+do_set_pattern(enum vlog_facility facility, const char *pattern)
 {
     struct facility *f = &facilities[facility];
     if (!f->default_pattern) {
@@ -256,7 +275,7 @@ int
 vlog_set_log_file(const char *file_name)
 {
     char *old_log_file_name;
-    enum vlog_module module;
+    struct vlog_module **mp;
     int error;
 
     /* Close old log file. */
@@ -271,15 +290,15 @@ vlog_set_log_file(const char *file_name)
     old_log_file_name = log_file_name;
     log_file_name = (file_name
                      ? xstrdup(file_name)
-                     : xasprintf("%s/%s.log", ovs_logdir, program_name));
+                     : xasprintf("%s/%s.log", ovs_logdir(), program_name));
     free(old_log_file_name);
     file_name = NULL;           /* Might have been freed. */
 
     /* Open new log file and update min_levels[] to reflect whether we actually
      * have a log_file. */
     log_file = fopen(log_file_name, "a");
-    for (module = 0; module < VLM_N_MODULES; module++) {
-        update_min_level(module);
+    for (mp = vlog_modules; mp < &vlog_modules[n_vlog_modules]; mp++) {
+        update_min_level(*mp);
     }
 
     /* Log success or failure. */
@@ -301,72 +320,99 @@ vlog_set_log_file(const char *file_name)
 int
 vlog_reopen_log_file(void)
 {
-    return log_file_name ? vlog_set_log_file(log_file_name) : 0;
+    struct stat old, new;
+
+    /* Skip re-opening if there's nothing to reopen. */
+    if (!log_file_name) {
+        return 0;
+    }
+
+    /* Skip re-opening if it would be a no-op because the old and new files are
+     * the same.  (This avoids writing "closing log file" followed immediately
+     * by "opened log file".) */
+    if (log_file
+        && !fstat(fileno(log_file), &old)
+        && !stat(log_file_name, &new)
+        && old.st_dev == new.st_dev
+        && old.st_ino == new.st_ino) {
+        return 0;
+    }
+
+    return vlog_set_log_file(log_file_name);
 }
 
-/* Set debugging levels:
- *
- *  mod[:facility[:level]] mod2[:facility[:level]] ...
- *
- * Return null if successful, otherwise an error message that the caller must
- * free().
- */
+/* Set debugging levels.  Returns null if successful, otherwise an error
+ * message that the caller must free(). */
 char *
 vlog_set_levels_from_string(const char *s_)
 {
-    char *save_ptr = NULL;
     char *s = xstrdup(s_);
-    char *module, *facility;
-
-    for (module = strtok_r(s, ": \t", &save_ptr); module != NULL;
-         module = strtok_r(NULL, ": \t", &save_ptr)) {
-        enum vlog_module e_module;
-        enum vlog_facility e_facility;
+    char *save_ptr = NULL;
+    char *msg = NULL;
+    char *word;
 
-        facility = strtok_r(NULL, ":", &save_ptr);
+    word = strtok_r(s, " ,:\t", &save_ptr);
+    if (word && !strcasecmp(word, "PATTERN")) {
+        enum vlog_facility facility;
 
-        if (!facility || !strcmp(facility, "ANY")) {
-            e_facility = VLF_ANY_FACILITY;
-        } else {
-            e_facility = vlog_get_facility_val(facility);
-            if (e_facility >= VLF_N_FACILITIES) {
-                char *msg = xasprintf("unknown facility \"%s\"", facility);
-                free(s);
-                return msg;
-            }
+        word = strtok_r(NULL, " ,:\t", &save_ptr);
+        if (!word) {
+            msg = xstrdup("missing facility");
+            goto exit;
         }
 
-        if (!strcmp(module, "PATTERN")) {
-            vlog_set_pattern(e_facility, save_ptr);
-            break;
-        } else {
-            char *level;
-            enum vlog_level e_level;
-
-            if (!strcmp(module, "ANY")) {
-                e_module = VLM_ANY_MODULE;
-            } else {
-                e_module = vlog_get_module_val(module);
-                if (e_module >= VLM_N_MODULES) {
-                    char *msg = xasprintf("unknown module \"%s\"", module);
-                    free(s);
-                    return msg;
+        facility = (!strcasecmp(word, "ANY")
+                    ? VLF_ANY_FACILITY
+                    : vlog_get_facility_val(word));
+        if (facility == VLF_N_FACILITIES) {
+            msg = xasprintf("unknown facility \"%s\"", word);
+            goto exit;
+        }
+        vlog_set_pattern(facility, save_ptr);
+    } else {
+        struct vlog_module *module = NULL;
+        enum vlog_level level = VLL_N_LEVELS;
+        enum vlog_facility facility = VLF_N_FACILITIES;
+
+        for (; word != NULL; word = strtok_r(NULL, " ,:\t", &save_ptr)) {
+            if (!strcasecmp(word, "ANY")) {
+                continue;
+            } else if (vlog_get_facility_val(word) != VLF_N_FACILITIES) {
+                if (facility != VLF_N_FACILITIES) {
+                    msg = xstrdup("cannot specify multiple facilities");
+                    goto exit;
                 }
+                facility = vlog_get_facility_val(word);
+            } else if (vlog_get_level_val(word) != VLL_N_LEVELS) {
+                if (level != VLL_N_LEVELS) {
+                    msg = xstrdup("cannot specify multiple levels");
+                    goto exit;
+                }
+                level = vlog_get_level_val(word);
+            } else if (vlog_module_from_name(word)) {
+                if (module) {
+                    msg = xstrdup("cannot specify multiple modules");
+                    goto exit;
+                }
+                module = vlog_module_from_name(word);
+            } else {
+                msg = xasprintf("no facility, level, or module \"%s\"", word);
+                goto exit;
             }
+        }
 
-            level = strtok_r(NULL, ":", &save_ptr);
-            e_level = level ? vlog_get_level_val(level) : VLL_DBG;
-            if (e_level >= VLL_N_LEVELS) {
-                char *msg = xasprintf("unknown level \"%s\"", level);
-                free(s);
-                return msg;
-            }
-
-            vlog_set_levels(e_module, e_facility, e_level);
+        if (facility == VLF_N_FACILITIES) {
+            facility = VLF_ANY_FACILITY;
         }
+        if (level == VLL_N_LEVELS) {
+            level = VLL_DBG;
+        }
+        vlog_set_levels(module, facility, level);
     }
+
+exit:
     free(s);
-    return NULL;
+    return msg;
 }
 
 /* If 'arg' is null, configure maximum verbosity.  Otherwise, sets
@@ -380,52 +426,67 @@ vlog_set_verbosity(const char *arg)
             ovs_fatal(0, "processing \"%s\": %s", arg, msg);
         }
     } else {
-        vlog_set_levels(VLM_ANY_MODULE, VLF_ANY_FACILITY, VLL_DBG);
+        vlog_set_levels(NULL, VLF_ANY_FACILITY, VLL_DBG);
     }
 }
 
 static void
-vlog_unixctl_set(struct unixctl_conn *conn, const char *args)
+vlog_unixctl_set(struct unixctl_conn *conn, int argc, const char *argv[],
+                 void *aux OVS_UNUSED)
 {
-    char *msg = vlog_set_levels_from_string(args);
-    unixctl_command_reply(conn, msg ? 501 : 202, msg);
-    free(msg);
+    int i;
+
+    for (i = 1; i < argc; i++) {
+        char *msg = vlog_set_levels_from_string(argv[i]);
+        if (msg) {
+            unixctl_command_reply_error(conn, msg);
+            free(msg);
+            return;
+        }
+    }
+    unixctl_command_reply(conn, NULL);
 }
 
 static void
-vlog_unixctl_list(struct unixctl_conn *conn, const char *args UNUSED)
+vlog_unixctl_list(struct unixctl_conn *conn, int argc OVS_UNUSED,
+                  const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
 {
     char *msg = vlog_get_levels();
-    unixctl_command_reply(conn, 200, msg);
+    unixctl_command_reply(conn, msg);
     free(msg);
 }
 
 static void
-vlog_unixctl_reopen(struct unixctl_conn *conn, const char *args UNUSED)
+vlog_unixctl_reopen(struct unixctl_conn *conn, int argc OVS_UNUSED,
+                    const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
 {
     if (log_file_name) {
         int error = vlog_reopen_log_file();
         if (error) {
-            unixctl_command_reply(conn, 503, strerror(errno));
+            unixctl_command_reply_error(conn, strerror(errno));
         } else {
-            unixctl_command_reply(conn, 202, NULL);
+            unixctl_command_reply(conn, NULL);
         }
     } else {
-        unixctl_command_reply(conn, 403, "Logging to file not configured");
+        unixctl_command_reply_error(conn, "Logging to file not configured");
     }
 }
 
-/* Initializes the logging subsystem. */
+/* Initializes the logging subsystem and registers its unixctl server
+ * commands. */
 void
-vlog_init(void) 
+vlog_init(void)
 {
     time_t now;
 
+    if (vlog_inited) {
+        return;
+    }
+    vlog_inited = true;
+
     openlog(program_name, LOG_NDELAY, LOG_DAEMON);
-    vlog_set_levels(VLM_ANY_MODULE, VLF_ANY_FACILITY, VLL_INFO);
 
-    boot_time = time_msec();
-    now = time_now();
+    now = time_wall();
     if (now < 0) {
         struct tm tm;
         char s[128];
@@ -435,16 +496,22 @@ vlog_init(void)
         VLOG_ERR("current time is negative: %s (%ld)", s, (long int) now);
     }
 
-    unixctl_command_register("vlog/set", vlog_unixctl_set);
-    unixctl_command_register("vlog/list", vlog_unixctl_list);
-    unixctl_command_register("vlog/reopen", vlog_unixctl_reopen);
+    unixctl_command_register(
+        "vlog/set", "{spec | PATTERN:facility:pattern}",
+        1, INT_MAX, vlog_unixctl_set, NULL);
+    unixctl_command_register("vlog/list", "", 0, 0, vlog_unixctl_list, NULL);
+    unixctl_command_register("vlog/reopen", "", 0, 0,
+                             vlog_unixctl_reopen, NULL);
 }
 
 /* Closes the logging subsystem. */
 void
-vlog_exit(void) 
+vlog_exit(void)
 {
-    closelog(); 
+    if (vlog_inited) {
+        closelog();
+        vlog_inited = false;
+    }
 }
 
 /* Print the current logging level for each module. */
@@ -452,19 +519,29 @@ char *
 vlog_get_levels(void)
 {
     struct ds s = DS_EMPTY_INITIALIZER;
-    enum vlog_module module;
+    struct vlog_module **mp;
+    struct svec lines = SVEC_EMPTY_INITIALIZER;
+    char *line;
+    size_t i;
 
     ds_put_format(&s, "                 console    syslog    file\n");
     ds_put_format(&s, "                 -------    ------    ------\n");
 
-    for (module = 0; module < VLM_N_MODULES; module++) {
-        ds_put_format(&s, "%-16s  %4s       %4s       %4s\n",
-           vlog_get_module_name(module),
-           vlog_get_level_name(vlog_get_level(module, VLF_CONSOLE)),
-           vlog_get_level_name(vlog_get_level(module, VLF_SYSLOG)),
-           vlog_get_level_name(vlog_get_level(module, VLF_FILE)));
+    for (mp = vlog_modules; mp < &vlog_modules[n_vlog_modules]; mp++) {
+        line = xasprintf("%-16s  %4s       %4s       %4s\n",
+           vlog_get_module_name(*mp),
+           vlog_get_level_name(vlog_get_level(*mp, VLF_CONSOLE)),
+           vlog_get_level_name(vlog_get_level(*mp, VLF_SYSLOG)),
+           vlog_get_level_name(vlog_get_level(*mp, VLF_FILE)));
+        svec_add_nocopy(&lines, line);
     }
 
+    svec_sort(&lines);
+    SVEC_FOR_EACH (i, line, &lines) {
+        ds_put_cstr(&s, line);
+    }
+    svec_destroy(&lines);
+
     return ds_cstr(&s);
 }
 
@@ -472,9 +549,9 @@ vlog_get_levels(void)
  * would cause some log output, false if that module and level are completely
  * disabled. */
 bool
-vlog_is_enabled(enum vlog_module module, enum vlog_level level)
+vlog_is_enabled(const struct vlog_module *module, enum vlog_level level)
 {
-    return min_vlog_levels[module] >= level;
+    return module->min_level >= level;
 }
 
 static const char *
@@ -493,7 +570,7 @@ fetch_braces(const char *p, const char *def, char *out, size_t out_size)
 }
 
 static void
-format_log_message(enum vlog_module module, enum vlog_level level,
+format_log_message(const struct vlog_module *module, enum vlog_level level,
                    enum vlog_facility facility, unsigned int msg_num,
                    const char *message, va_list args_, struct ds *s)
 {
@@ -538,7 +615,11 @@ format_log_message(enum vlog_module module, enum vlog_level level,
             break;
         case 'd':
             p = fetch_braces(p, "%Y-%m-%d %H:%M:%S", tmp, sizeof tmp);
-            ds_put_strftime(s, tmp, NULL);
+            ds_put_strftime(s, tmp, false);
+            break;
+        case 'D':
+            p = fetch_braces(p, "%Y-%m-%d %H:%M:%S", tmp, sizeof tmp);
+            ds_put_strftime(s, tmp, true);
             break;
         case 'm':
             /* Format user-supplied log message and trim trailing new-lines. */
@@ -563,7 +644,7 @@ format_log_message(enum vlog_module module, enum vlog_level level,
             ds_put_format(s, "%ld", (long int) getpid());
             break;
         case 'r':
-            ds_put_format(s, "%lld", time_msec() - boot_time);
+            ds_put_format(s, "%lld", time_msec() - time_boot_msec());
             break;
         default:
             ds_put_char(s, p[-1]);
@@ -588,17 +669,19 @@ format_log_message(enum vlog_module module, enum vlog_level level,
  *
  * Guaranteed to preserve errno. */
 void
-vlog_valist(enum vlog_module module, enum vlog_level level,
+vlog_valist(const struct vlog_module *module, enum vlog_level level,
             const char *message, va_list args)
 {
-    bool log_to_console = levels[module][VLF_CONSOLE] >= level;
-    bool log_to_syslog = levels[module][VLF_SYSLOG] >= level;
-    bool log_to_file = levels[module][VLF_FILE] >= level && log_file;
+    bool log_to_console = module->levels[VLF_CONSOLE] >= level;
+    bool log_to_syslog = module->levels[VLF_SYSLOG] >= level;
+    bool log_to_file = module->levels[VLF_FILE] >= level && log_file;
     if (log_to_console || log_to_syslog || log_to_file) {
         int save_errno = errno;
         static unsigned int msg_num;
         struct ds s;
 
+        vlog_init();
+
         ds_init(&s);
         ds_reserve(&s, 1024);
         msg_num++;
@@ -637,7 +720,8 @@ vlog_valist(enum vlog_module module, enum vlog_level level,
 }
 
 void
-vlog(enum vlog_module module, enum vlog_level level, const char *message, ...)
+vlog(const struct vlog_module *module, enum vlog_level level,
+     const char *message, ...)
 {
     va_list args;
 
@@ -646,8 +730,32 @@ vlog(enum vlog_module module, enum vlog_level level, const char *message, ...)
     va_end(args);
 }
 
+void
+vlog_fatal_valist(const struct vlog_module *module_,
+                  const char *message, va_list args)
+{
+    struct vlog_module *module = (struct vlog_module *) module_;
+
+    /* Don't log this message to the console to avoid redundancy with the
+     * message written by the later ovs_fatal_valist(). */
+    module->levels[VLF_CONSOLE] = VLL_OFF;
+
+    vlog_valist(module, VLL_EMER, message, args);
+    ovs_fatal_valist(0, message, args);
+}
+
+void
+vlog_fatal(const struct vlog_module *module, const char *message, ...)
+{
+    va_list args;
+
+    va_start(args, message);
+    vlog_fatal_valist(module, message, args);
+    va_end(args);
+}
+
 bool
-vlog_should_drop(enum vlog_module module, enum vlog_level level,
+vlog_should_drop(const struct vlog_module *module, enum vlog_level level,
                  struct vlog_rate_limit *rl)
 {
     if (!vlog_is_enabled(module, level)) {
@@ -670,6 +778,7 @@ vlog_should_drop(enum vlog_module module, enum vlog_level level,
             if (!rl->n_dropped) {
                 rl->first_dropped = now;
             }
+            rl->last_dropped = now;
             rl->n_dropped++;
             return true;
         }
@@ -677,17 +786,22 @@ vlog_should_drop(enum vlog_module module, enum vlog_level level,
     rl->tokens -= VLOG_MSG_TOKENS;
 
     if (rl->n_dropped) {
+        time_t now = time_now();
+        unsigned int first_dropped_elapsed = now - rl->first_dropped;
+        unsigned int last_dropped_elapsed = now - rl->last_dropped;
+
         vlog(module, level,
-             "Dropped %u log messages in last %u seconds "
-             "due to excessive rate",
-             rl->n_dropped, (unsigned int) (time_now() - rl->first_dropped));
+             "Dropped %u log messages in last %u seconds (most recently, "
+             "%u seconds ago) due to excessive rate",
+             rl->n_dropped, first_dropped_elapsed, last_dropped_elapsed);
+
         rl->n_dropped = 0;
     }
     return false;
 }
 
 void
-vlog_rate_limit(enum vlog_module module, enum vlog_level level,
+vlog_rate_limit(const struct vlog_module *module, enum vlog_level level,
                 struct vlog_rate_limit *rl, const char *message, ...)
 {
     if (!vlog_should_drop(module, level, rl)) {
@@ -700,12 +814,12 @@ vlog_rate_limit(enum vlog_module module, enum vlog_level level,
 }
 
 void
-vlog_usage(void) 
+vlog_usage(void)
 {
     printf("\nLogging options:\n"
-           "  -v, --verbose=MODULE[:FACILITY[:LEVEL]]  set logging levels\n"
+           "  -v, --verbose=[SPEC]    set logging levels\n"
            "  -v, --verbose           set maximum verbosity level\n"
            "  --log-file[=FILE]       enable logging to specified FILE\n"
            "                          (default: %s/%s.log)\n",
-           ovs_logdir, program_name);
+           ovs_logdir(), program_name);
 }