MXS-1914: Move maxscale_shutdown() into the core

The core library now contains the maxscale_shutdown() command. This makes
it possible to resolve all symbols at link time even for administrative
modules.

include/maxscale/log_manager.h

@@ -96,6 +96,18 @@ typedef struct mxs_log_throttling
 bool mxs_log_init(const char* ident, const char* logdir, mxs_log_target_t target);
 void mxs_log_finish(void);
 
+/**
+ * Start log flushing thread
+ *
+ * @return True if log flusher thread was started
+ */
+bool mxs_log_start_flush_thr();
+
+/**
+ * Stop log flushing thread
+ */
+void mxs_log_stop_flush_thr();
+
 int mxs_log_flush();
 int mxs_log_flush_sync();
 int mxs_log_rotate();

server/core/gateway.cc

@@ -90,11 +90,6 @@ static bool     datadir_defined = false; /*< If the datadir was already set */
 static char     pidfile[PATH_MAX + 1] = "";
 static int pidfd = PIDFD_CLOSED;
 
-/**
- * exit flag for log flusher.
- */
-static bool do_exit = false;
-
 /**
  * If MaxScale is started to run in daemon process the value is true.
  */
@@ -146,8 +141,6 @@ static bool unload_modules_at_exit = true;
 static std::string redirect_output_to;
 
 static int cnf_preparser(void* data, const char* section, const char* name, const char* value);
-static void log_flush_shutdown(void);
-static void log_flush_cb(void* arg);
 static int write_pid_file(); /* write MaxScale pidfile */
 static void unlink_pidfile(void); /* remove pidfile */
 static void unlock_pidfile();
@@ -1420,7 +1413,6 @@ int main(int argc, char **argv)
     int      child_status;
     char*    cnf_file_path = NULL;        /*< conf file, to be freed */
     char*    cnf_file_arg = NULL;         /*< conf filename from cmd-line arg */
-    THREAD    log_flush_thr;
     char*    tmp_path;
     int      option_index;
     MXS_CONFIG* cnf = config_get_global_options();
@@ -1428,7 +1420,6 @@ int main(int argc, char **argv)
     int      *syslog_enabled = &cnf->syslog; /** Log to syslog */
     int      *maxlog_enabled = &cnf->maxlog; /** Log with MaxScale */
     int      *log_to_shm = &cnf->log_to_shm; /** Log to shared memory */
-    ssize_t  log_flush_timeout_ms = 0;
     sigset_t sigpipe_mask;
     sigset_t saved_mask;
     bool to_stdout = false;
@@ -2185,12 +2176,7 @@ int main(int argc, char **argv)
         goto return_main;
     }
 
-    /*<
+    if (!mxs_log_start_flush_thr())
-     * Start periodic log flusher thread.
-     */
-    log_flush_timeout_ms = 1000;
-
-    if (thread_start(&log_flush_thr, log_flush_cb, (void *) &log_flush_timeout_ms, 0) == NULL)
     {
         const char* logerr = "Failed to start log flushing thread.";
         print_log_n_stderr(true, true, logerr, logerr, 0);
@@ -2283,10 +2269,7 @@ int main(int argc, char **argv)
     Worker::finish();
     MessageQueue::finish();
 
-    /*<
+    mxs_log_stop_flush_thr();
-     * Wait the flush thread.
-     */
-    thread_wait(log_flush_thr);
 
     /*< Call finish on all modules. */
     modules_process_finish();
@@ -2336,57 +2319,6 @@ return_main:
     return rc;
 } /*< End of main */
 
-/*<
- * Shutdown MaxScale server
- */
-int maxscale_shutdown()
-{
-    static int n_shutdowns = 0;
-
-    int n = atomic_add(&n_shutdowns, 1);
-
-    if (n == 0)
-    {
-        service_shutdown();
-        Worker::shutdown_all();
-        log_flush_shutdown();
-    }
-
-    return n + 1;
-}
-
-static void log_flush_shutdown(void)
-{
-    do_exit = true;
-}
-
-
-/**
- * Periodic log flusher to ensure that log buffers are
- * written to log even if block buffer used for temporarily
- * storing log contents are not full.
- *
- * @param arg - Flush frequency in milliseconds
- *
- *
- */
-static void log_flush_cb(void* arg)
-{
-    ssize_t timeout_ms = *(ssize_t *)arg;
-    struct timespec ts1;
-
-    ts1.tv_sec = timeout_ms / 1000;
-    ts1.tv_nsec = (timeout_ms % 1000) * 1000000;
-
-    MXS_NOTICE("Started MaxScale log flusher.");
-    while (!do_exit)
-    {
-        mxs_log_flush();
-        nanosleep(&ts1, NULL);
-    }
-    MXS_NOTICE("Finished MaxScale log flusher.");
-}
-
 static void unlock_pidfile()
 {
     if (pidfd != PIDFD_CLOSED)

server/core/log_manager.cc

@@ -25,6 +25,7 @@
 #include <sys/types.h>
 #include <syslog.h>
 #include <unistd.h>
+#include <atomic>
 
 #include <maxscale/alloc.h>
 #include <maxscale/atomic.h>
@@ -34,6 +35,7 @@
 #include <maxscale/platform.h>
 #include <maxscale/session.h>
 #include <maxscale/spinlock.hh>
+#include <maxscale/thread.h>
 #include <maxscale/utils.h>
 #include "internal/mlist.h"
 
@@ -821,6 +823,32 @@ void mxs_log_finish(void)
     spinlock_release(&lmlock);
 }
 
+static struct
+{
+    THREAD thr;
+    std::atomic<bool> running{true};
+} log_flusher;
+
+static void log_flush_cb(void* arg)
+{
+    while (log_flusher.running)
+    {
+        mxs_log_flush();
+        sleep(1);
+    }
+}
+
+bool mxs_log_start_flush_thr()
+{
+    return thread_start(&log_flusher.thr, log_flush_cb, NULL, 0);
+}
+
+void mxs_log_stop_flush_thr()
+{
+    log_flusher.running = false;
+    thread_wait(log_flusher.thr);
+}
+
 static logfile_t* logmanager_get_logfile(logmanager_t* lmgr)
 {
     logfile_t* lf;

server/core/misc.cc

@@ -14,7 +14,11 @@
 #include <maxscale/maxscale.h>
 
 #include <time.h>
+
+#include <maxscale/worker.hh>
+
 #include "internal/maxscale.h"
+#include "internal/service.h"
 
 static time_t started;
 
@@ -32,3 +36,18 @@ int maxscale_uptime()
 {
     return time(0) - started;
 }
+
+int maxscale_shutdown()
+{
+    static int n_shutdowns = 0;
+
+    int n = atomic_add(&n_shutdowns, 1);
+
+    if (n == 0)
+    {
+        service_shutdown();
+        mxs::Worker::shutdown_all();
+    }
+
+    return n + 1;
+}