added support for server going dormant

diff --git a/server/mr_main.c b/server/mr_main.c
index 351f38500731fb845b77b225ca88fcc5693d52ec..9e589be37f2f35ea53c38d0eda8ec3d000f1fcf8 100644 (file)
--- a/server/mr_main.c
+++ b/server/mr_main.c
@@ -20,9 +20,11 @@ static char *rcsid_sms_main_c = "$Header$";
 
 #include <mit-copyright.h>
 #include <strings.h>
+#include <sys/types.h>
 #include <sys/errno.h>
 #include <sys/signal.h>
 #include <sys/wait.h>
+#include <sys/stat.h>
 #include "sms_server.h"
 #include <krb_et.h>
 
@@ -54,7 +56,7 @@ extern void do_client();
 extern int sigshut();
 void clist_append();
 void oplist_append();
-void reapchild();
+void reapchild(), godormant(), gowakeup();
 
 extern time_t now;
 
@@ -73,6 +75,7 @@ main(argc, argv)
 {
        int status;
        time_t tardy;
+       struct stat stbuf;
        
        whoami = argv[0];
        /*
@@ -126,13 +129,17 @@ main(argc, argv)
        
        /*
         * Signal handlers
-        *      There should probably be a few more of these.
+        *      There should probably be a few more of these. This is
+        *      duplicated on the next page, be sure to also add any
+        *      additional handlers there.
         */
        
        if ((((int)signal (SIGTERM, sigshut)) < 0) ||
            (((int)signal (SIGCHLD, reapchild)) < 0) ||
+           (((int)signal (SIGUSR1, godormant)) < 0) ||
+           (((int)signal (SIGUSR2, gowakeup)) < 0) ||
            (((int)signal (SIGHUP, sigshut)) < 0)) {
-               com_err(whoami, errno, " Unable to establish signal handler.");
+               com_err(whoami, errno, " Unable to establish signal handlers.");
                exit(1);
        }
        
@@ -168,13 +175,34 @@ main(argc, argv)
 #ifdef notdef
                com_err(whoami, 0, "tick");
 #endif notdef
+               if (dormant == SLEEPY) {
+                   sms_close_database();
+                   com_err(whoami, 0, "database closed");
+                   send_zgram("SMS", "database closed");
+                   dormant = ASLEEP;
+               } else if (dormant == GROGGY) {
+                   sms_open_database();
+                   com_err(whoami, 0, "database open");
+                   if ((((int)signal (SIGTERM, sigshut)) < 0) ||
+                       (((int)signal (SIGCHLD, reapchild)) < 0) ||
+                       (((int)signal (SIGUSR1, godormant)) < 0) ||
+                       (((int)signal (SIGUSR2, gowakeup)) < 0) ||
+                       (((int)signal (SIGHUP, sigshut)) < 0)) {
+                       com_err(whoami, errno,
+                               " Unable to reestablish signal handlers.");
+                       exit(1);
+                   }
+                   send_zgram("SMS", "database open again");
+                   dormant = AWAKE;
+               }
+
                errno = 0;
                status = op_select_any(op_list, 0,
                                       (fd_set *)NULL, (fd_set *)NULL,
                                       (fd_set *)NULL, (struct timeval *)NULL);
 
                if (status == -1) {
-                       com_err(whoami, errno, " error from op_select");
+                       com_err(whoami, errno, " error from op_select");
                        continue;
                } else if (status != -2) {
                        com_err(whoami, 0, " wrong return from op_select_any");
@@ -205,6 +233,25 @@ main(argc, argv)
                                 * Sleep here to prevent hosing?
                                 */
                        }
+                       /* if the new connection is our only connection,
+                        * and the server is supposed to be down, then go
+                        * down now.
+                        */
+                       if ((dormant == AWAKE) && (nclients == 1) &&
+                           (stat(SMS_MOTD_FILE, &stbuf) == 0)) {
+                           com_err(whoami, 0, "motd file exists, slumbertime");
+                           dormant = SLEEPY;
+                       }
+                       /* on new connection, if we are no longer supposed
+                        * to be down, then wake up.
+                        */
+                       if ((dormant == ASLEEP) &&
+                           (stat(SMS_MOTD_FILE, &stbuf) == -1) &&
+                           (errno == ENOENT)) {
+                           com_err(whoami, 0, "motd file no longer exists, waking up");
+                           dormant = GROGGY;
+                       }
+                         
                }
                /*
                 * Handle any existing connections.
@@ -442,13 +489,47 @@ void reapchild()
     union wait status;
     int pid;
 
-    if (takedown)
+    if (takedown || dormant == ASLEEP)
       return;
     while ((pid = wait3(&status, WNOHANG, (struct rusage *)0)) > 0) {
        if  (status.w_termsig == 0 && status.w_retcode == 0)
-         com_err(whoami, 0, "dcm started successfully");
+         com_err(whoami, 0, "child exited successfully");
        else
-         com_err(whoami, 0, "%d: startdcm exits with signal %d status %d",
+         com_err(whoami, 0, "%d: child exits with signal %d status %d",
                  pid, status.w_termsig, status.w_retcode);
     }
 }
+
+
+void godormant()
+{
+    switch (dormant) {
+    case AWAKE:
+    case GROGGY:
+       com_err(whoami, 0, "requested to go dormant");
+       break;
+    case ASLEEP:
+       com_err(whoami, 0, "already asleep");
+       break;
+    case SLEEPY:
+       break;
+    }
+    dormant = SLEEPY;
+}
+
+
+void gowakeup()
+{
+    switch (dormant) {
+    case ASLEEP:
+    case SLEEPY:
+       com_err(whoami, 0, "Good morning");
+       break;
+    case AWAKE:
+       com_err(whoami, 0, "already awake");
+       break;
+    case GROGGY:
+       break;
+    }
+    dormant = GROGGY;
+}