server/mr_main.c

   1 /*
   2  *      $Source$
   3  *      $Author$
   4  *      $Header$
   5  *
   6  *      Copyright (C) 1987 by the Massachusetts Institute of Technology
   7  *      For copying and distribution information, please see the file
   8  *      <mit-copyright.h>.
   9  *
  10  *      SMS server process.
  11  *
  12  *      Most of this is stolen from ../gdb/tsr.c
  13  *
  14  *      You are in a maze of twisty little finite automata, all different.
  15  *      Let the reader beware.
  16  *
  17  */
  18
  19 static char *rcsid_sms_main_c = "$Header$";
  20
  21 #include <mit-copyright.h>
  22 #include <strings.h>
  23 #include <sys/types.h>
  24 #include <sys/errno.h>
  25 #include <sys/signal.h>
  26 #include <sys/wait.h>
  27 #include <sys/stat.h>
  28 #include "sms_server.h"
  29 #include <krb_et.h>
  30
  31 extern CONNECTION newconn, listencon;
  32
  33 extern int nclients;
  34 extern client **clients, *cur_client;
  35
  36 extern OPERATION listenop;
  37 extern LIST_OF_OPERATIONS op_list;
  38
  39 extern struct sockaddr_in client_addr;
  40 extern int client_addrlen;
  41 extern TUPLE client_tuple;
  42
  43 extern char *whoami;
  44 extern char buf1[BUFSIZ];
  45 extern char *takedown;
  46 extern int errno;
  47 extern FILE *journal;
  48 #define JOURNAL "/u1/sms/journal"
  49
  50 extern char *malloc();
  51 extern int free();
  52 extern char *inet_ntoa();
  53 extern void sms_com_err();
  54 extern void do_client();
  55
  56 extern int sigshut();
  57 void clist_append();
  58 void oplist_append();
  59 void reapchild(), godormant(), gowakeup();
  60
  61 extern time_t now;
  62
  63 /*
  64  * Main SMS server loop.
  65  *
  66  * Initialize the world, then start accepting connections and
  67  * making progress on current connections.
  68  */
  69
  70 /*ARGSUSED*/
  71 int
  72 main(argc, argv)
  73         int argc;
  74         char **argv;
  75 {
  76         int status;
  77         time_t tardy;
  78         struct stat stbuf;
  79
  80         whoami = argv[0];
  81         /*
  82          * Error handler init.
  83          */
  84         initialize_sms_error_table();
  85         initialize_krb_error_table();
  86         set_com_err_hook(sms_com_err);
  87         setlinebuf(stderr);
  88
  89         if (argc != 1) {
  90                 com_err(whoami, 0, "Usage: smsd");
  91                 exit(1);
  92         }
  93
  94         /* Profiling implies that getting rid of one level of call
  95          * indirection here wins us maybe 1% on the VAX.
  96          */
  97         gdb_amv = malloc;
  98         gdb_fmv = free;
  99
 100         /*
 101          * GDB initialization.
 102          */
 103         if(gdb_init() != 0) {
 104                 com_err(whoami, 0, "GDB initialization failed.");
 105                 exit(1);
 106         }
 107         gdb_debug(0); /* this can be patched, if necessary, to enable */
 108                       /* GDB level debugging .. */
 109         krb_realm = malloc(REALM_SZ);
 110         get_krbrlm(krb_realm, 1);
 111
 112         /*
 113          * Database initialization.  Only init if database should be open.
 114          */
 115
 116         if (stat(SMS_MOTD_FILE, &stbuf) != 0) {
 117             if ((status = sms_open_database()) != 0) {
 118                 com_err(whoami, status, " when trying to open database.");
 119                 exit(1);
 120             }
 121             sanity_check_database();
 122         } else {
 123             dormant = ASLEEP;
 124             com_err(whoami, 0, "sleeping, not opening database");
 125         }
 126
 127         sanity_check_queries();
 128
 129         /*
 130          * Set up client array handler.
 131          */
 132         nclients = 0;
 133         clients = (client **) malloc(0);
 134
 135         sms_setup_signals();
 136
 137         journal = fopen(JOURNAL, "a");
 138         if (journal == NULL) {
 139             com_err(whoami, errno, " while opening journal file");
 140             exit(1);
 141         }
 142
 143         /*
 144          * Establish template connection.
 145          */
 146         if ((status = do_listen()) != 0) {
 147                 com_err(whoami, status,
 148                         " while trying to create listening connection");
 149                 exit(1);
 150         }
 151
 152         op_list = create_list_of_operations(1, listenop);
 153
 154         com_err(whoami, 0, "started (pid %d)", getpid());
 155         com_err(whoami, 0, rcsid_sms_main_c);
 156         if (dormant != ASLEEP)
 157           send_zgram("SMS", "server started");
 158         else
 159           send_zgram("SMS", "server started, but database closed");
 160
 161         /*
 162          * Run until shut down.
 163          */
 164         while(!takedown) {
 165                 register int i;
 166                 /*
 167                  * Block until something happens.
 168                  */
 169 #ifdef notdef
 170                 com_err(whoami, 0, "tick");
 171 #endif notdef
 172                 if (dormant == SLEEPY) {
 173                     sms_close_database();
 174                     com_err(whoami, 0, "database closed");
 175                     sms_setup_signals();
 176                     send_zgram("SMS", "database closed");
 177                     dormant = ASLEEP;
 178                 } else if (dormant == GROGGY) {
 179                     sms_open_database();
 180                     com_err(whoami, 0, "database open");
 181                     sms_setup_signals();
 182                     send_zgram("SMS", "database open again");
 183                     dormant = AWAKE;
 184                 }
 185
 186                 errno = 0;
 187                 status = op_select_any(op_list, 0,
 188                                        (fd_set *)NULL, (fd_set *)NULL,
 189                                        (fd_set *)NULL, (struct timeval *)NULL);
 190
 191                 if (status == -1) {
 192                         com_err(whoami, errno, " error from op_select");
 193                         continue;
 194                 } else if (status != -2) {
 195                         com_err(whoami, 0, " wrong return from op_select_any");
 196                         continue;
 197                 }
 198                 if (takedown) break;
 199                 time(&now);
 200 #ifdef notdef
 201                 fprintf(stderr, "    tick\n");
 202 #endif notdef
 203                 /*
 204                  * Handle any new connections; this comes first so
 205                  * errno isn't tromped on.
 206                  */
 207                 if (OP_DONE(listenop)) {
 208                         if (OP_STATUS(listenop) == OP_CANCELLED) {
 209                                 if (errno == EWOULDBLOCK) {
 210                                         do_reset_listen();
 211                                 } else {
 212                                         com_err(whoami, errno,
 213                                                 " error on listen");
 214                                         exit(1);
 215                                 }
 216                         } else if ((status = new_connection()) != 0) {
 217                                 com_err(whoami, errno,
 218                                         " Error on listening operation.");
 219                                 /*
 220                                  * Sleep here to prevent hosing?
 221                                  */
 222                         }
 223                         /* if the new connection is our only connection,
 224                          * and the server is supposed to be down, then go
 225                          * down now.
 226                          */
 227                         if ((dormant == AWAKE) && (nclients == 1) &&
 228                             (stat(SMS_MOTD_FILE, &stbuf) == 0)) {
 229                             com_err(whoami, 0, "motd file exists, slumbertime");
 230                             dormant = SLEEPY;
 231                         }
 232                         /* on new connection, if we are no longer supposed
 233                          * to be down, then wake up.
 234                          */
 235                         if ((dormant == ASLEEP) &&
 236                             (stat(SMS_MOTD_FILE, &stbuf) == -1) &&
 237                             (errno == ENOENT)) {
 238                             com_err(whoami, 0, "motd file no longer exists, waking up");
 239                             dormant = GROGGY;
 240                         }
 241
 242                 }
 243                 /*
 244                  * Handle any existing connections.
 245                  */
 246                 tardy = now - 30*60;
 247
 248                 for (i=0; i<nclients; i++) {
 249                         cur_client = clients[i];
 250                         if (OP_DONE(clients[i]->pending_op)) {
 251                                 cur_client->last_time_used = now;
 252                                 do_client(cur_client);
 253                         } else if (clients[i]->last_time_used < tardy) {
 254                                 com_err(whoami, 0, "Shutting down connection due to inactivity");
 255                                 shutdown(cur_client->con->in.fd, 0);
 256                         }
 257                         cur_client = NULL;
 258                         if (takedown) break;
 259                 }
 260         }
 261         com_err(whoami, 0, "%s", takedown);
 262         sms_close_database();
 263         send_zgram("SMS", takedown);
 264         return 0;
 265 }
 266
 267 /*
 268  * Set up the template connection and queue the first accept.
 269  */
 270
 271 int
 272 do_listen()
 273 {
 274         char *service = index(SMS_GDB_SERV, ':') + 1;
 275
 276         listencon = create_listening_connection(service);
 277
 278         if (listencon == NULL)
 279                 return errno;
 280
 281         listenop = create_operation();
 282         client_addrlen = sizeof(client_addr);
 283
 284         start_accepting_client(listencon, listenop, &newconn,
 285                                (char *)&client_addr,
 286                                &client_addrlen, &client_tuple);
 287         return 0;
 288 }
 289
 290
 291 do_reset_listen()
 292 {
 293         client_addrlen = sizeof(client_addr);
 294         start_accepting_client(listencon, listenop, &newconn,
 295                                (char *)&client_addr,
 296                                &client_addrlen, &client_tuple);
 297 }
 298
 299 /*
 300  * This routine is called when a new connection comes in.
 301  *
 302  * It sets up a new client and adds it to the list of currently active clients.
 303  */
 304 int
 305 new_connection()
 306 {
 307         register client *cp;
 308         static counter = 0;
 309
 310         /*
 311          * Make sure there's been no error
 312          */
 313         if(OP_STATUS(listenop) != OP_COMPLETE) {
 314                 return errno;
 315         }
 316
 317         if (newconn == NULL) {
 318                 return SMS_NOT_CONNECTED;
 319         }
 320
 321         /*
 322          * Set up the new connection and reply to the client
 323          */
 324         cp = (client *)malloc(sizeof *cp);
 325         bzero(cp, sizeof(*cp));
 326         cp->action = CL_ACCEPT;
 327         cp->con = newconn;
 328         cp->id = counter++;
 329         cp->args = NULL;
 330         cp->clname = NULL;
 331         cp->reply.sms_argv = NULL;
 332         cp->first = NULL;
 333         cp->last = NULL;
 334         cp->last_time_used = now;
 335         newconn = NULL;
 336
 337         cp->pending_op = create_operation();
 338         reset_operation(cp->pending_op);
 339         oplist_append(&op_list, cp->pending_op);
 340         cur_client = cp;
 341
 342         /*
 343          * Add a new client to the array..
 344          */
 345         clist_append(cp);
 346
 347         /*
 348          * Let him know we heard him.
 349          */
 350         start_replying_to_client(cp->pending_op, cp->con, GDB_ACCEPTED,
 351                                  "", "");
 352
 353         cp->haddr = client_addr;
 354
 355         /*
 356          * Log new connection.
 357          */
 358
 359         com_err(whoami, 0, "New connection from %s port %d (now %d client%s)",
 360                 inet_ntoa(cp->haddr.sin_addr),
 361                 (int)ntohs(cp->haddr.sin_port),
 362                 nclients,
 363                 nclients!=1?"s":"");
 364
 365         /*
 366          * Get ready to accept the next connection.
 367          */
 368         reset_operation(listenop);
 369         client_addrlen = sizeof(client_addr);
 370
 371         start_accepting_client(listencon, listenop, &newconn,
 372                                (char *)&client_addr,
 373                                &client_addrlen, &client_tuple);
 374         return 0;
 375 }
 376
 377 /*
 378  * Add a new client to the known clients.
 379  */
 380 void
 381 clist_append(cp)
 382         client *cp;
 383 {
 384         client **clients_n;
 385
 386         nclients++;
 387         clients_n = (client **)malloc
 388                 ((unsigned)(nclients * sizeof(client *)));
 389         bcopy((char *)clients, (char *)clients_n, (nclients-1)*sizeof(cp));
 390         clients_n[nclients-1] = cp;
 391         free((char *)clients);
 392         clients = clients_n;
 393         clients_n = NULL;
 394 }
 395
 396
 397 void
 398 clist_delete(cp)
 399         client *cp;
 400 {
 401         client **clients_n, **scpp, **dcpp; /* source and dest client */
 402                                             /* ptr ptr */
 403
 404         int found_it = 0;
 405
 406         clients_n = (client **)malloc
 407                 ((unsigned)((nclients - 1)* sizeof(client *)));
 408         for (scpp = clients, dcpp = clients_n; scpp < clients+nclients; ) {
 409                 if (*scpp != cp) {
 410                         *dcpp++ = *scpp++;
 411                 } else {
 412                         scpp++;
 413                         if (found_it) abort();
 414                         found_it = 1;
 415                 }
 416         }
 417         --nclients;
 418         free((char *)clients);
 419         clients = clients_n;
 420         clients_n = NULL;
 421         oplist_delete(op_list, cp->pending_op);
 422         reset_operation(cp->pending_op);
 423         delete_operation(cp->pending_op);
 424         sever_connection(cp->con);
 425         free((char *)cp);
 426 }
 427
 428 /*
 429  * Add a new operation to a list of operations.
 430  *
 431  * This should be rewritten to use realloc instead, since in most
 432  * cases it won't have to copy the array.
 433  */
 434
 435 void
 436 oplist_append(oplp, op)
 437         LIST_OF_OPERATIONS *oplp;
 438         OPERATION op;
 439 {
 440         int count = (*oplp)->count+1;
 441         LIST_OF_OPERATIONS newlist = (LIST_OF_OPERATIONS)
 442                 db_alloc(size_of_list_of_operations(count));
 443         bcopy((char *)(*oplp), (char *)newlist,
 444               size_of_list_of_operations((*oplp)->count));
 445         newlist->count++;
 446         newlist->op[count-1] = op;
 447         db_free((char *)(*oplp), size_of_list_of_operations(count-1));
 448         (*oplp) = newlist;
 449 }
 450
 451
 452 oplist_delete(oplp, op)
 453         LIST_OF_OPERATIONS oplp;
 454         register OPERATION op;
 455 {
 456         register OPERATION *s;
 457         register int c;
 458
 459         for (s = oplp->op, c=oplp->count; c; --c, ++s) {
 460                 if (*s == op) {
 461                         while (c > 0) {
 462                                 *s = *(s+1);
 463                                 ++s;
 464                                 --c;
 465                         }
 466                         oplp->count--;
 467                         return;
 468                 }
 469         }
 470         abort();
 471 }
 472
 473
 474 void reapchild()
 475 {
 476     union wait status;
 477     int pid;
 478
 479     if (takedown || dormant == ASLEEP)
 480       return;
 481     while ((pid = wait3(&status, WNOHANG, (struct rusage *)0)) > 0) {
 482         if  (status.w_termsig == 0 && status.w_retcode == 0)
 483           com_err(whoami, 0, "child exited successfully");
 484         else
 485           com_err(whoami, 0, "%d: child exits with signal %d status %d",
 486                   pid, status.w_termsig, status.w_retcode);
 487     }
 488 }
 489
 490
 491 void godormant()
 492 {
 493     switch (dormant) {
 494     case AWAKE:
 495     case GROGGY:
 496         com_err(whoami, 0, "requested to go dormant");
 497         break;
 498     case ASLEEP:
 499         com_err(whoami, 0, "already asleep");
 500         break;
 501     case SLEEPY:
 502         break;
 503     }
 504     dormant = SLEEPY;
 505 }
 506
 507
 508 void gowakeup()
 509 {
 510     switch (dormant) {
 511     case ASLEEP:
 512     case SLEEPY:
 513         com_err(whoami, 0, "Good morning");
 514         break;
 515     case AWAKE:
 516         com_err(whoami, 0, "already awake");
 517         break;
 518     case GROGGY:
 519         break;
 520     }
 521     dormant = GROGGY;
 522 }
 523
 524
 525 sms_setup_signals()
 526 {
 527     /* There should probably be a few more of these. */
 528
 529     if ((((int)signal (SIGTERM, sigshut)) < 0) ||
 530         (((int)signal (SIGCHLD, reapchild)) < 0) ||
 531         (((int)signal (SIGUSR1, godormant)) < 0) ||
 532         (((int)signal (SIGUSR2, gowakeup)) < 0) ||
 533         (((int)signal (SIGHUP, sigshut)) < 0)) {
 534         com_err(whoami, errno, " Unable to establish signal handlers.");
 535         exit(1);
 536     }
 537 }