citadel/citserver.c

   1 /*
   2  * Main source module for the Citadel server
   3  *
   4  * Copyright (c) 1987-2011 by the citadel.org team
   5  *
   6  * This program is open source software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 3.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include "sysdep.h"
  16 #include <stdlib.h>
  17 #include <unistd.h>
  18 #include <stdio.h>
  19 #include <fcntl.h>
  20 #include <signal.h>
  21 #include <sys/types.h>
  22 #include <sys/stat.h>
  23
  24 #if TIME_WITH_SYS_TIME
  25 # include <sys/time.h>
  26 # include <time.h>
  27 #else
  28 # if HAVE_SYS_TIME_H
  29 #  include <sys/time.h>
  30 # else
  31 #  include <time.h>
  32 # endif
  33 #endif
  34
  35 #if HAVE_BACKTRACE
  36 #include <execinfo.h>
  37 #endif
  38
  39 #include <ctype.h>
  40 #include <string.h>
  41 #include <dirent.h>
  42 #include <errno.h>
  43 #include <limits.h>
  44 #include <netdb.h>
  45 #include <sys/types.h>
  46 #include <sys/socket.h>
  47 #include <netinet/in.h>
  48 #include <arpa/inet.h>
  49 #include <libcitadel.h>
  50 #include "citadel.h"
  51 #include "server.h"
  52 #include "sysdep_decls.h"
  53 #include "threads.h"
  54 #include "citserver.h"
  55 #include "config.h"
  56 #include "database.h"
  57 #include "housekeeping.h"
  58 #include "user_ops.h"
  59 #include "msgbase.h"
  60 #include "support.h"
  61 #include "locate_host.h"
  62 #include "room_ops.h"
  63 #include "control.h"
  64 #include "euidindex.h"
  65 #include "context.h"
  66 #include "svn_revision.h"
  67 #include "ctdl_module.h"
  68
  69 char *unique_session_numbers;
  70 int ScheduledShutdown = 0;
  71 time_t server_startup_time;
  72 int panic_fd;
  73 int openid_level_supported = 0;
  74
  75 /*
  76  * print the actual stack frame.
  77  */
  78 void cit_backtrace(void)
  79 {
  80 #ifdef HAVE_BACKTRACE
  81         void *stack_frames[50];
  82         size_t size, i;
  83         char **strings;
  84
  85
  86         size = backtrace(stack_frames, sizeof(stack_frames) / sizeof(void*));
  87         strings = backtrace_symbols(stack_frames, size);
  88         for (i = 0; i < size; i++) {
  89                 if (strings != NULL)
  90                         syslog(LOG_ALERT, "%s\n", strings[i]);
  91                 else
  92                         syslog(LOG_ALERT, "%p\n", stack_frames[i]);
  93         }
  94         free(strings);
  95 #endif
  96 }
  97
  98 void cit_oneline_backtrace(void)
  99 {
 100 #ifdef HAVE_BACKTRACE
 101         void *stack_frames[50];
 102         size_t size, i;
 103         char **strings;
 104         StrBuf *Buf;
 105
 106         size = backtrace(stack_frames, sizeof(stack_frames) / sizeof(void*));
 107         strings = backtrace_symbols(stack_frames, size);
 108         if (size > 0)
 109         {
 110                 Buf = NewStrBuf();
 111                 for (i = 1; i < size; i++) {
 112                         if (strings != NULL)
 113                                 StrBufAppendPrintf(Buf, "%s : ", strings[i]);
 114                         else
 115                                 StrBufAppendPrintf(Buf, "%p : ", stack_frames[i]);
 116                 }
 117                 free(strings);
 118                 syslog(LOG_ALERT, "%s\n", ChrPtr(Buf));
 119                 FreeStrBuf(&Buf);
 120         }
 121 #endif
 122 }
 123
 124 /*
 125  * print the actual stack frame.
 126  */
 127 void cit_panic_backtrace(int SigNum)
 128 {
 129 #ifdef HAVE_BACKTRACE
 130         void *stack_frames[10];
 131         size_t size, i;
 132         char **strings;
 133
 134         printf("caught signal 11\n");
 135         size = backtrace(stack_frames, sizeof(stack_frames) / sizeof(void*));
 136         strings = backtrace_symbols(stack_frames, size);
 137         for (i = 0; i < size; i++) {
 138                 if (strings != NULL)
 139                         syslog(LOG_ALERT, "%s\n", strings[i]);
 140                 else
 141                         syslog(LOG_ALERT, "%p\n", stack_frames[i]);
 142         }
 143         free(strings);
 144 #endif
 145         exit(-1);
 146 }
 147
 148 /*
 149  * Various things that need to be initialized at startup
 150  */
 151 void master_startup(void) {
 152         struct timeval tv;
 153         unsigned int seed;
 154         FILE *urandom;
 155         struct ctdlroom qrbuf;
 156         int rv;
 157
 158         syslog(LOG_DEBUG, "master_startup() started\n");
 159         time(&server_startup_time);
 160         get_config();
 161
 162         syslog(LOG_INFO, "Opening databases\n");
 163         open_databases();
 164         check_ref_counts();
 165
 166         syslog(LOG_INFO, "Creating base rooms (if necessary)\n");
 167         CtdlCreateRoom(config.c_baseroom,       0, "", 0, 1, 0, VIEW_BBS);
 168         CtdlCreateRoom(AIDEROOM,                3, "", 0, 1, 0, VIEW_BBS);
 169         CtdlCreateRoom(SYSCONFIGROOM,           3, "", 0, 1, 0, VIEW_BBS);
 170         CtdlCreateRoom(config.c_twitroom,       0, "", 0, 1, 0, VIEW_BBS);
 171
 172         /* The "Local System Configuration" room doesn't need to be visible */
 173         if (CtdlGetRoomLock(&qrbuf, SYSCONFIGROOM) == 0) {
 174                 qrbuf.QRflags2 |= QR2_SYSTEM;
 175                 CtdlPutRoomLock(&qrbuf);
 176         }
 177
 178         /* Aide needs to be public postable, else we're not RFC conformant. */
 179         if (CtdlGetRoomLock(&qrbuf, AIDEROOM) == 0) {
 180                 qrbuf.QRflags2 |= QR2_SMTP_PUBLIC;
 181                 CtdlPutRoomLock(&qrbuf);
 182         }
 183
 184         syslog(LOG_INFO, "Seeding the pseudo-random number generator...\n");
 185         urandom = fopen("/dev/urandom", "r");
 186         if (urandom != NULL) {
 187                 rv = fread(&seed, sizeof seed, 1, urandom);
 188                 if (rv == -1)
 189                         syslog(LOG_EMERG, "failed to read random seed: %s\n",
 190                                strerror(errno));
 191                 fclose(urandom);
 192         }
 193         else {
 194                 gettimeofday(&tv, NULL);
 195                 seed = tv.tv_usec;
 196         }
 197         srand(seed);
 198         srandom(seed);
 199
 200         put_config();
 201
 202         syslog(LOG_DEBUG, "master_startup() finished\n");
 203 }
 204
 205
 206 /*
 207  * Cleanup routine to be called when the server is shutting down.
 208  */
 209 void master_cleanup(int exitcode) {
 210         struct CleanupFunctionHook *fcn;
 211         static int already_cleaning_up = 0;
 212
 213         if (already_cleaning_up) while(1) usleep(1000000);
 214         already_cleaning_up = 1;
 215
 216         /* Run any cleanup routines registered by loadable modules */
 217         for (fcn = CleanupHookTable; fcn != NULL; fcn = fcn->next) {
 218                 (*fcn->h_function_pointer)();
 219         }
 220
 221         /* Close the AdjRefCount queue file */
 222         AdjRefCount(-1, 0);
 223
 224         /* Do system-dependent stuff */
 225         sysdep_master_cleanup();
 226
 227         /* Close databases */
 228         syslog(LOG_INFO, "Closing databases\n");
 229         close_databases();
 230
 231         /* If the operator requested a halt but not an exit, halt here. */
 232         if (shutdown_and_halt) {
 233                 syslog(LOG_NOTICE, "citserver: Halting server without exiting.\n");
 234                 fflush(stdout); fflush(stderr);
 235                 while(1) {
 236                         sleep(32767);
 237                 }
 238         }
 239
 240         release_control();
 241
 242         /* Now go away. */
 243         syslog(LOG_NOTICE, "citserver: Exiting with status %d\n", exitcode);
 244         fflush(stdout); fflush(stderr);
 245
 246         if (restart_server != 0)
 247                 exit(1);
 248         if ((running_as_daemon != 0) && ((exitcode == 0) ))
 249                 exitcode = CTDLEXIT_SHUTDOWN;
 250         exit(exitcode);
 251 }
 252
 253
 254
 255 /*
 256  * returns an asterisk if there are any instant messages waiting,
 257  * space otherwise.
 258  */
 259 char CtdlCheckExpress(void) {
 260         if (CC->FirstExpressMessage == NULL) {
 261                 return(' ');
 262         }
 263         else {
 264                 return('*');
 265         }
 266 }
 267
 268
 269 /*
 270  * Check originating host against the public_clients file.  This determines
 271  * whether the client is allowed to change the hostname for this session
 272  * (for example, to show the location of the user rather than the location
 273  * of the client).
 274  */
 275 int CtdlIsPublicClient(void)
 276 {
 277         char buf[1024];
 278         char addrbuf[1024];
 279         FILE *fp;
 280         int i;
 281         char *public_clientspos;
 282         char *public_clientsend;
 283         char *paddr = NULL;
 284         struct stat statbuf;
 285         static time_t pc_timestamp = 0;
 286         static char public_clients[SIZ];
 287         static char public_clients_file[SIZ];
 288
 289 #define LOCALHOSTSTR "127.0.0.1"
 290
 291         snprintf(public_clients_file, sizeof public_clients_file, "%s/public_clients", ctdl_etc_dir);
 292
 293         /*
 294          * Check the time stamp on the public_clients file.  If it's been
 295          * updated since the last time we were here (or if this is the first
 296          * time we've been through the loop), read its contents and learn
 297          * the IP addresses of the listed hosts.
 298          */
 299         if (stat(public_clients_file, &statbuf) != 0) {
 300                 /* No public_clients file exists, so bail out */
 301                 syslog(LOG_WARNING, "Warning: '%s' does not exist\n",
 302                                 public_clients_file);
 303                 return(0);
 304         }
 305
 306         if (statbuf.st_mtime > pc_timestamp) {
 307                 begin_critical_section(S_PUBLIC_CLIENTS);
 308                 syslog(LOG_INFO, "Loading %s\n", public_clients_file);
 309
 310                 public_clientspos = &public_clients[0];
 311                 public_clientsend = public_clientspos + SIZ;
 312                 safestrncpy(public_clientspos, LOCALHOSTSTR, sizeof public_clients);
 313                 public_clientspos += sizeof(LOCALHOSTSTR) - 1;
 314
 315                 if (hostname_to_dotted_quad(addrbuf, config.c_fqdn) == 0) {
 316                         *(public_clientspos++) = '|';
 317                         paddr = &addrbuf[0];
 318                         while (!IsEmptyStr (paddr) &&
 319                                (public_clientspos < public_clientsend))
 320                                 *(public_clientspos++) = *(paddr++);
 321                 }
 322
 323                 fp = fopen(public_clients_file, "r");
 324                 if (fp != NULL)
 325                         while ((fgets(buf, sizeof buf, fp)!=NULL) &&
 326                                (public_clientspos < public_clientsend)){
 327                                 char *ptr;
 328                                 ptr = buf;
 329                                 while (!IsEmptyStr(ptr)) {
 330                                         if (*ptr == '#') {
 331                                                 *ptr = 0;
 332                                                 break;
 333                                         }
 334                                 else ptr++;
 335                                 }
 336                                 ptr--;
 337                                 while (ptr>buf && isspace(*ptr)) {
 338                                         *(ptr--) = 0;
 339                                 }
 340                                 if (hostname_to_dotted_quad(addrbuf, buf) == 0) {
 341                                         *(public_clientspos++) = '|';
 342                                         paddr = addrbuf;
 343                                         while (!IsEmptyStr(paddr) &&
 344                                                (public_clientspos < public_clientsend)){
 345                                                 *(public_clientspos++) = *(paddr++);
 346                                         }
 347                                 }
 348                         }
 349                 if (fp != NULL) fclose(fp);
 350                 pc_timestamp = time(NULL);
 351                 end_critical_section(S_PUBLIC_CLIENTS);
 352         }
 353
 354         syslog(LOG_DEBUG, "Checking whether %s is a local or public client\n",
 355                 CC->cs_addr);
 356         for (i=0; i<num_parms(public_clients); ++i) {
 357                 extract_token(addrbuf, public_clients, i, '|', sizeof addrbuf);
 358                 if (!strcasecmp(CC->cs_addr, addrbuf)) {
 359                         syslog(LOG_DEBUG, "... yes its local.\n");
 360                         return(1);
 361                 }
 362         }
 363
 364         /* No hits.  This is not a public client. */
 365         syslog(LOG_DEBUG, "... no it isn't.\n");
 366         return(0);
 367 }
 368
 369
 370
 371 /*
 372  * help_subst()  -  support routine for help file viewer
 373  */
 374 void help_subst(char *strbuf, char *source, char *dest)
 375 {
 376         char workbuf[SIZ];
 377         int p;
 378
 379         while (p = pattern2(strbuf, source), (p >= 0)) {
 380                 strcpy(workbuf, &strbuf[p + strlen(source)]);
 381                 strcpy(&strbuf[p], dest);
 382                 strcat(strbuf, workbuf);
 383         }
 384 }
 385
 386 void do_help_subst(char *buffer)
 387 {
 388         char buf2[16];
 389
 390         help_subst(buffer, "^nodename", config.c_nodename);
 391         help_subst(buffer, "^humannode", config.c_humannode);
 392         help_subst(buffer, "^fqdn", config.c_fqdn);
 393         help_subst(buffer, "^username", CC->user.fullname);
 394         snprintf(buf2, sizeof buf2, "%ld", CC->user.usernum);
 395         help_subst(buffer, "^usernum", buf2);
 396         help_subst(buffer, "^sysadm", config.c_sysadm);
 397         help_subst(buffer, "^variantname", CITADEL);
 398         snprintf(buf2, sizeof buf2, "%d", config.c_maxsessions);
 399         help_subst(buffer, "^maxsessions", buf2);
 400         help_subst(buffer, "^bbsdir", ctdl_message_dir);
 401 }
 402
 403
 404 typedef const char *ccharp;
 405 /*
 406  * display system messages or help
 407  */
 408 void cmd_mesg(char *mname)
 409 {
 410         FILE *mfp;
 411         char targ[256];
 412         char buf[256];
 413         char buf2[256];
 414         char *dirs[2];
 415         DIR *dp;
 416         struct dirent *d;
 417
 418         extract_token(buf, mname, 0, '|', sizeof buf);
 419
 420         dirs[0] = strdup(ctdl_message_dir);
 421         dirs[1] = strdup(ctdl_hlp_dir);
 422
 423         snprintf(buf2, sizeof buf2, "%s.%d.%d",
 424                 buf, CC->cs_clientdev, CC->cs_clienttyp);
 425
 426         /* If the client requested "?" then produce a listing */
 427         if (!strcmp(buf, "?")) {
 428                 cprintf("%d %s\n", LISTING_FOLLOWS, buf);
 429                 dp = opendir(dirs[1]);
 430                 if (dp != NULL) {
 431                         while (d = readdir(dp), d != NULL) {
 432                                 if (d->d_name[0] != '.') {
 433                                         cprintf(" %s\n", d->d_name);
 434                                 }
 435                         }
 436                         closedir(dp);
 437                 }
 438                 cprintf("000\n");
 439                 free(dirs[0]);
 440                 free(dirs[1]);
 441                 return;
 442         }
 443
 444         /* Otherwise, look for the requested file by name. */
 445         else {
 446                 mesg_locate(targ, sizeof targ, buf2, 2, (const ccharp*)dirs);
 447                 if (IsEmptyStr(targ)) {
 448                         snprintf(buf2, sizeof buf2, "%s.%d",
 449                                                         buf, CC->cs_clientdev);
 450                         mesg_locate(targ, sizeof targ, buf2, 2,
 451                                     (const ccharp*)dirs);
 452                         if (IsEmptyStr(targ)) {
 453                                 mesg_locate(targ, sizeof targ, buf, 2,
 454                                             (const ccharp*)dirs);
 455                         }
 456                 }
 457         }
 458
 459         free(dirs[0]);
 460         free(dirs[1]);
 461
 462         if (IsEmptyStr(targ)) {
 463                 cprintf("%d '%s' not found.  (Searching in %s and %s)\n",
 464                         ERROR + FILE_NOT_FOUND,
 465                         mname,
 466                         ctdl_message_dir,
 467                         ctdl_hlp_dir
 468                 );
 469                 return;
 470         }
 471
 472         mfp = fopen(targ, "r");
 473         if (mfp==NULL) {
 474                 cprintf("%d Cannot open '%s': %s\n",
 475                         ERROR + INTERNAL_ERROR, targ, strerror(errno));
 476                 return;
 477         }
 478         cprintf("%d %s\n", LISTING_FOLLOWS,buf);
 479
 480         while (fgets(buf, (sizeof buf - 1), mfp) != NULL) {
 481                 buf[strlen(buf)-1] = 0;
 482                 do_help_subst(buf);
 483                 cprintf("%s\n",buf);
 484         }
 485
 486         fclose(mfp);
 487         cprintf("000\n");
 488 }
 489
 490
 491 /*
 492  * enter system messages or help
 493  */
 494 void cmd_emsg(char *mname)
 495 {
 496         FILE *mfp;
 497         char targ[256];
 498         char buf[256];
 499         char *dirs[2];
 500         int a;
 501
 502         unbuffer_output();
 503
 504         if (CtdlAccessCheck(ac_aide)) return;
 505
 506         extract_token(buf, mname, 0, '|', sizeof buf);
 507         for (a=0; !IsEmptyStr(&buf[a]); ++a) {          /* security measure */
 508                 if (buf[a] == '/') buf[a] = '.';
 509         }
 510
 511         dirs[0] = strdup(ctdl_message_dir);
 512         dirs[1] = strdup(ctdl_hlp_dir);
 513
 514         mesg_locate(targ, sizeof targ, buf, 2, (const ccharp*)dirs);
 515         free(dirs[0]);
 516         free(dirs[1]);
 517
 518         if (IsEmptyStr(targ)) {
 519                 snprintf(targ, sizeof targ,
 520                                  "%s/%s",
 521                                  ctdl_hlp_dir, buf);
 522         }
 523
 524         mfp = fopen(targ,"w");
 525         if (mfp==NULL) {
 526                 cprintf("%d Cannot open '%s': %s\n",
 527                         ERROR + INTERNAL_ERROR, targ, strerror(errno));
 528                 return;
 529         }
 530         cprintf("%d %s\n", SEND_LISTING, targ);
 531
 532         while (client_getln(buf, sizeof buf) >=0 && strcmp(buf, "000")) {
 533                 fprintf(mfp, "%s\n", buf);
 534         }
 535
 536         fclose(mfp);
 537 }
 538
 539
 540 /* Don't show the names of private rooms unless the viewing
 541  * user also knows the rooms.
 542  */
 543 void GenerateRoomDisplay(char *real_room,
 544                         CitContext *viewed,
 545                         CitContext *viewer) {
 546
 547         int ra;
 548
 549         strcpy(real_room, viewed->room.QRname);
 550         if (viewed->room.QRflags & QR_MAILBOX) {
 551                 strcpy(real_room, &real_room[11]);
 552         }
 553         if (viewed->room.QRflags & QR_PRIVATE) {
 554                 CtdlRoomAccess(&viewed->room, &viewer->user, &ra, NULL);
 555                 if ( (ra & UA_KNOWN) == 0) {
 556                         strcpy(real_room, " ");
 557                 }
 558         }
 559
 560         if (viewed->cs_flags & CS_CHAT) {
 561                 while (strlen(real_room) < 14) {
 562                         strcat(real_room, " ");
 563                 }
 564                 strcpy(&real_room[14], "<chat>");
 565         }
 566
 567 }
 568
 569 /*
 570  * Convenience function.
 571  */
 572 int CtdlAccessCheck(int required_level) {
 573
 574         if (CC->internal_pgm) return(0);
 575         if (required_level >= ac_internal) {
 576                 cprintf("%d This is not a user-level command.\n",
 577                         ERROR + HIGHER_ACCESS_REQUIRED);
 578                 return(-1);
 579         }
 580
 581         if ((required_level >= ac_logged_in_or_guest) && (CC->logged_in == 0) && (!config.c_guest_logins)) {
 582                 cprintf("%d Not logged in.\n", ERROR + NOT_LOGGED_IN);
 583                 return(-1);
 584         }
 585
 586         if ((required_level >= ac_logged_in) && (CC->logged_in == 0)) {
 587                 cprintf("%d Not logged in.\n", ERROR + NOT_LOGGED_IN);
 588                 return(-1);
 589         }
 590
 591         if (CC->user.axlevel >= AxAideU) return(0);
 592         if (required_level >= ac_aide) {
 593                 cprintf("%d This command requires Admin access.\n",
 594                         ERROR + HIGHER_ACCESS_REQUIRED);
 595                 return(-1);
 596         }
 597
 598         if (is_room_aide()) return(0);
 599         if (required_level >= ac_room_aide) {
 600                 cprintf("%d This command requires Admin or Room Admin access.\n",
 601                         ERROR + HIGHER_ACCESS_REQUIRED);
 602                 return(-1);
 603         }
 604
 605         /* shhh ... succeed quietly */
 606         return(0);
 607 }
 608
 609
 610
 611
 612
 613
 614 /*
 615  * Shut down the server
 616  */
 617 void cmd_down(char *argbuf) {
 618         char *Reply ="%d Shutting down server.  Goodbye.\n";
 619
 620         if (CtdlAccessCheck(ac_aide)) return;
 621
 622         if (!IsEmptyStr(argbuf))
 623         {
 624                 int state = CIT_OK;
 625                 restart_server = extract_int(argbuf, 0);
 626
 627                 if (restart_server > 0)
 628                 {
 629                         Reply = "%d citserver will now shut down and automatically restart.\n";
 630                 }
 631                 if ((restart_server > 0) && !running_as_daemon)
 632                 {
 633                         syslog(LOG_ERR, "The user requested restart, but not running as daemon! Geronimooooooo!\n");
 634                         Reply = "%d Warning: citserver is not running in daemon mode and is therefore unlikely to restart automatically.\n";
 635                         state = ERROR;
 636                 }
 637                 cprintf(Reply, state);
 638         }
 639         else
 640         {
 641                 cprintf(Reply, CIT_OK + SERVER_SHUTTING_DOWN);
 642         }
 643         CC->kill_me = KILLME_SERVER_SHUTTING_DOWN;
 644         server_shutting_down = 1;
 645 }
 646
 647
 648 /*
 649  * Halt the server without exiting the server process.
 650  */
 651 void cmd_halt(char *argbuf) {
 652
 653         if (CtdlAccessCheck(ac_aide)) return;
 654
 655         cprintf("%d Halting server.  Goodbye.\n", CIT_OK);
 656         server_shutting_down = 1;
 657         shutdown_and_halt = 1;
 658 }
 659
 660
 661 /*
 662  * Schedule or cancel a server shutdown
 663  */
 664 void cmd_scdn(char *argbuf)
 665 {
 666         int new_state;
 667         int state = CIT_OK;
 668         char *Reply = "%d %d\n";
 669
 670         if (CtdlAccessCheck(ac_aide)) return;
 671
 672         new_state = extract_int(argbuf, 0);
 673         if ((new_state == 2) || (new_state == 3))
 674         {
 675                 restart_server = 1;
 676                 if (!running_as_daemon)
 677                 {
 678                         syslog(LOG_ERR, "The user requested restart, but not running as deamon! Geronimooooooo!\n");
 679                         Reply = "%d %d Warning, not running in deamon mode. maybe we will come up again, but don't lean on it.\n";
 680                         state = ERROR;
 681                 }
 682
 683                 restart_server = extract_int(argbuf, 0);
 684                 new_state -= 2;
 685         }
 686         if ((new_state == 0) || (new_state == 1)) {
 687                 ScheduledShutdown = new_state;
 688         }
 689         cprintf(Reply, state, ScheduledShutdown);
 690 }
 691
 692
 693
 694 /*
 695  * Back-end function for starting a session
 696  */
 697 void begin_session(CitContext *con)
 698 {
 699         /*
 700          * Initialize some variables specific to our context.
 701          */
 702         con->logged_in = 0;
 703         con->internal_pgm = 0;
 704         con->download_fp = NULL;
 705         con->upload_fp = NULL;
 706         con->cached_msglist = NULL;
 707         con->cached_num_msgs = 0;
 708         con->FirstExpressMessage = NULL;
 709         time(&con->lastcmd);
 710         time(&con->lastidle);
 711         strcpy(con->lastcmdname, "    ");
 712         strcpy(con->cs_clientname, "(unknown)");
 713         strcpy(con->curr_user, NLI);
 714         *con->net_node = '\0';
 715         *con->fake_username = '\0';
 716         *con->fake_hostname = '\0';
 717         *con->fake_roomname = '\0';
 718         *con->cs_clientinfo = '\0';
 719         safestrncpy(con->cs_host, config.c_fqdn, sizeof con->cs_host);
 720         safestrncpy(con->cs_addr, "", sizeof con->cs_addr);
 721         con->cs_UDSclientUID = -1;
 722         con->cs_host[sizeof con->cs_host - 1] = 0;
 723         if (!CC->is_local_socket) {
 724                 locate_host(con->cs_host, sizeof con->cs_host,
 725                         con->cs_addr, sizeof con->cs_addr,
 726                         con->client_socket
 727                 );
 728         }
 729         else {
 730                 con->cs_host[0] = 0;
 731                 con->cs_addr[0] = 0;
 732 #ifdef HAVE_STRUCT_UCRED
 733                 {
 734                         /* as http://www.wsinnovations.com/softeng/articles/uds.html told us... */
 735                         struct ucred credentials;
 736                         socklen_t ucred_length = sizeof(struct ucred);
 737
 738                         /*fill in the user data structure */
 739                         if(getsockopt(con->client_socket, SOL_SOCKET, SO_PEERCRED, &credentials, &ucred_length)) {
 740                                 syslog(LOG_NOTICE, "could obtain credentials from unix domain socket");
 741
 742                         }
 743                         else {
 744                                 /* the process ID of the process on the other side of the socket */
 745                                 /* credentials.pid; */
 746
 747                                 /* the effective UID of the process on the other side of the socket  */
 748                                 con->cs_UDSclientUID = credentials.uid;
 749
 750                                 /* the effective primary GID of the process on the other side of the socket */
 751                                 /* credentials.gid; */
 752
 753                                 /* To get supplemental groups, we will have to look them up in our account
 754                                    database, after a reverse lookup on the UID to get the account name.
 755                                    We can take this opportunity to check to see if this is a legit account.
 756                                 */
 757                                 snprintf(con->cs_clientinfo, sizeof(con->cs_clientinfo),
 758                                          "PID: "F_PID_T"; UID: "F_UID_T"; GID: "F_XPID_T" ",
 759                                          credentials.pid,
 760                                          credentials.uid,
 761                                          credentials.gid);
 762                         }
 763                 }
 764 #endif
 765         }
 766         con->cs_flags = 0;
 767         con->upload_type = UPL_FILE;
 768         con->dl_is_net = 0;
 769
 770         con->nologin = 0;
 771         if (((config.c_maxsessions > 0)&&(num_sessions > config.c_maxsessions)) || CtdlWantSingleUser()) {
 772                 con->nologin = 1;
 773         }
 774
 775         if (!CC->is_local_socket) {
 776                 syslog(LOG_NOTICE, "Session (%s) started from %s (%s).\n", con->ServiceName, con->cs_host, con->cs_addr);
 777         }
 778         else {
 779                 syslog(LOG_NOTICE, "Session (%s) started via local socket UID:%d.\n", con->ServiceName, con->cs_UDSclientUID);
 780         }
 781
 782         /* Run any session startup routines registered by loadable modules */
 783         PerformSessionHooks(EVT_START);
 784 }
 785
 786
 787 void citproto_begin_session() {
 788         if (CC->nologin==1) {
 789                 cprintf("%d %s: Too many users are already online (maximum is %d)\n",
 790                         ERROR + MAX_SESSIONS_EXCEEDED,
 791                         config.c_nodename, config.c_maxsessions
 792                 );
 793                 CC->kill_me = KILLME_MAX_SESSIONS_EXCEEDED;
 794         }
 795         else {
 796                 cprintf("%d %s Citadel server ready.\n", CIT_OK, config.c_nodename);
 797                 CC->can_receive_im = 1;
 798         }
 799 }
 800
 801
 802 void citproto_begin_admin_session() {
 803         CC->internal_pgm = 1;
 804         cprintf("%d %s Citadel server ADMIN CONNECTION ready.\n", CIT_OK, config.c_nodename);
 805 }
 806
 807
 808
 809
 810 /*
 811  * This loop recognizes all server commands.
 812  */
 813 void do_command_loop(void) {
 814         char cmdbuf[SIZ];
 815
 816         time(&CC->lastcmd);
 817         memset(cmdbuf, 0, sizeof cmdbuf); /* Clear it, just in case */
 818         if (client_getln(cmdbuf, sizeof cmdbuf) < 1) {
 819                 syslog(LOG_ERR, "Citadel client disconnected: ending session.\n");
 820                 CC->kill_me = KILLME_CLIENT_DISCONNECTED;
 821                 return;
 822         }
 823
 824         /* Log the server command, but don't show passwords... */
 825         if ( (strncasecmp(cmdbuf, "PASS", 4)) && (strncasecmp(cmdbuf, "SETP", 4)) ) {
 826                 syslog(LOG_INFO, "[%d][%s(%ld)] %s",
 827                         CC->cs_pid, CC->curr_user, CC->user.usernum, cmdbuf
 828                 );
 829         }
 830         else {
 831                 syslog(LOG_INFO, "[%d][%s(%ld)] <password command hidden from log>",
 832                         CC->cs_pid, CC->curr_user, CC->user.usernum
 833                 );
 834         }
 835
 836         buffer_output();
 837
 838         /*
 839          * Let other clients see the last command we executed, and
 840          * update the idle time, but not NOOP, QNOP, PEXP, GEXP, RWHO, or TIME.
 841          */
 842         if ( (strncasecmp(cmdbuf, "NOOP", 4))
 843            && (strncasecmp(cmdbuf, "QNOP", 4))
 844            && (strncasecmp(cmdbuf, "PEXP", 4))
 845            && (strncasecmp(cmdbuf, "GEXP", 4))
 846            && (strncasecmp(cmdbuf, "RWHO", 4))
 847            && (strncasecmp(cmdbuf, "TIME", 4)) ) {
 848                 strcpy(CC->lastcmdname, "    ");
 849                 safestrncpy(CC->lastcmdname, cmdbuf, sizeof(CC->lastcmdname));
 850                 time(&CC->lastidle);
 851         }
 852
 853         if ((strncasecmp(cmdbuf, "ENT0", 4))
 854            && (strncasecmp(cmdbuf, "MESG", 4))
 855            && (strncasecmp(cmdbuf, "MSGS", 4)))
 856         {
 857            CC->cs_flags &= ~CS_POSTING;
 858         }
 859
 860         if (!DLoader_Exec_Cmd(cmdbuf)) {
 861                 cprintf("%d Unrecognized or unsupported command.\n", ERROR + CMD_NOT_SUPPORTED);
 862         }
 863
 864         unbuffer_output();
 865
 866         /* Run any after-each-command routines registered by modules */
 867         PerformSessionHooks(EVT_CMD);
 868 }
 869
 870
 871 /*
 872  * This loop performs all asynchronous functions.
 873  */
 874 void do_async_loop(void) {
 875         PerformSessionHooks(EVT_ASYNC);
 876 }
 877
 878
 879 /*****************************************************************************/
 880 /*                      MODULE INITIALIZATION STUFF                          */
 881 /*****************************************************************************/
 882
 883 CTDL_MODULE_INIT(citserver)
 884 {
 885         if (!threading) {
 886
 887                 CtdlRegisterProtoHook(cmd_mesg, "MESG", "fetch system banners");
 888                 CtdlRegisterProtoHook(cmd_emsg, "EMSG", "submit system banners");
 889 ;
 890                 CtdlRegisterProtoHook(cmd_down, "DOWN", "perform a server shutdown");
 891                 CtdlRegisterProtoHook(cmd_halt, "HALT", "halt the server without exiting the server process");
 892                 CtdlRegisterProtoHook(cmd_scdn, "SCDN", "schedule or cancel a server shutdown");
 893         }
 894         /* return our id for the Log */
 895         return "citserver";
 896 }