citadel/sysdep.c

   1 // Citadel "system dependent" stuff.
   2 //
   3 // Here's where we (hopefully) have most parts of the Citadel server that
   4 // might need tweaking when run on different operating system variants.
   5 //
   6 // Copyright (c) 1987-2021 by the citadel.org team
   7 //
   8 // This program is open source software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License, version 3.
  10 //
  11 // This program is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 #include "sysdep.h"
  17 #include <stdlib.h>
  18 #include <unistd.h>
  19 #include <sys/stat.h>
  20 #include <errno.h>
  21 #include <signal.h>
  22 #include <stdio.h>
  23 #include <syslog.h>
  24 #include <sys/syslog.h>
  25 #include <execinfo.h>
  26 #include <netdb.h>
  27 #include <sys/un.h>
  28 #include <sys/types.h>
  29 #include <sys/socket.h>
  30 #include <netinet/in.h>
  31 #include <arpa/inet.h>
  32 #include <netinet/tcp.h>
  33 #include <arpa/inet.h>
  34 #define SHOW_ME_VAPPEND_PRINTF
  35 #include <libcitadel.h>
  36 #include "citserver.h"
  37 #include "config.h"
  38 #include "ctdl_module.h"
  39 #include "sysdep_decls.h"
  40 #include "modules/crypto/serv_crypto.h" // Needed for init_ssl, client_write_ssl, client_read_ssl, destruct_ssl
  41 #include "housekeeping.h"
  42 #include "context.h"
  43
  44 // Signal handler to shut down the server.
  45 volatile int exit_signal = 0;
  46 volatile int shutdown_and_halt = 0;
  47 volatile int restart_server = 0;
  48 volatile int running_as_daemon = 0;
  49
  50
  51 static RETSIGTYPE signal_cleanup(int signum) {
  52         syslog(LOG_DEBUG, "sysdep: caught signal %d - backtrace follows:", signum);
  53
  54         void *bt[1024];
  55         int bt_size;
  56         char **bt_syms;
  57         int i;
  58
  59         bt_size = backtrace(bt, 1024);
  60         bt_syms = backtrace_symbols(bt, bt_size);
  61         for (i = 1; i < bt_size; i++) {
  62                 syslog(LOG_DEBUG, "%s", bt_syms[i]);
  63         }
  64         free(bt_syms);
  65
  66         exit_signal = signum;
  67         server_shutting_down = 1;
  68 }
  69
  70
  71 // Some initialization stuff...
  72 void init_sysdep(void) {
  73         sigset_t set;
  74
  75         // Avoid vulnerabilities related to FD_SETSIZE if we can.
  76 #ifdef FD_SETSIZE
  77 #ifdef RLIMIT_NOFILE
  78         struct rlimit rl;
  79         getrlimit(RLIMIT_NOFILE, &rl);
  80         rl.rlim_cur = FD_SETSIZE;
  81         rl.rlim_max = FD_SETSIZE;
  82         setrlimit(RLIMIT_NOFILE, &rl);
  83 #endif
  84 #endif
  85
  86         // If we've got OpenSSL, we're going to use it.
  87 #ifdef HAVE_OPENSSL
  88         init_ssl();
  89 #endif
  90
  91         if (pthread_key_create(&ThreadKey, NULL) != 0) {                        // TSD for threads
  92                 syslog(LOG_ERR, "pthread_key_create() : %m");
  93                 abort();
  94         }
  95
  96         if (pthread_key_create(&MyConKey, NULL) != 0) {                         // TSD for sessions
  97                 syslog(LOG_CRIT, "sysdep: can't create TSD key: %m");
  98                 abort();
  99         }
 100
 101         // Interript, hangup, and terminate signals should cause the server to shut down.
 102         sigemptyset(&set);
 103         sigaddset(&set, SIGINT);
 104         sigaddset(&set, SIGHUP);
 105         sigaddset(&set, SIGTERM);
 106         sigaddset(&set, SIGSEGV);
 107         sigprocmask(SIG_UNBLOCK, &set, NULL);
 108
 109         signal(SIGINT, signal_cleanup);
 110         signal(SIGHUP, signal_cleanup);
 111         signal(SIGTERM, signal_cleanup);
 112         signal(SIGSEGV, signal_cleanup);
 113
 114         // Do not shut down the server on broken pipe signals, otherwise the
 115         // whole Citadel service would come down whenever a single client
 116         // socket breaks.
 117         signal(SIGPIPE, SIG_IGN);
 118 }
 119
 120
 121 // This is a generic function to set up a master socket for listening on
 122 // a TCP port.  The server shuts down if the bind fails.  (IPv4/IPv6 version)
 123 //
 124 // ip_addr      IP address to bind
 125 // port_number  port number to bind
 126 // queue_len    number of incoming connections to allow in the queue
 127 int ctdl_tcp_server(char *ip_addr, int port_number, int queue_len) {
 128         struct protoent *p;
 129         struct sockaddr_in6 sin6;
 130         struct sockaddr_in sin4;
 131         int s, i, b;
 132         int ip_version = 6;
 133
 134         memset(&sin6, 0, sizeof(sin6));
 135         memset(&sin4, 0, sizeof(sin4));
 136         sin6.sin6_family = AF_INET6;
 137         sin4.sin_family = AF_INET;
 138
 139         if (    (ip_addr == NULL)                                                       // any IPv6
 140                 || (IsEmptyStr(ip_addr))
 141                 || (!strcmp(ip_addr, "*"))
 142         ) {
 143                 ip_version = 6;
 144                 sin6.sin6_addr = in6addr_any;
 145         }
 146         else if (!strcmp(ip_addr, "0.0.0.0"))                                           // any IPv4
 147         {
 148                 ip_version = 4;
 149                 sin4.sin_addr.s_addr = INADDR_ANY;
 150         }
 151         else if ((strchr(ip_addr, '.')) && (!strchr(ip_addr, ':')))                     // specific IPv4
 152         {
 153                 ip_version = 4;
 154                 if (inet_pton(AF_INET, ip_addr, &sin4.sin_addr) <= 0) {
 155                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 156                         return (-1);
 157                 }
 158         }
 159         else                                                                            // specific IPv6
 160         {
 161                 ip_version = 6;
 162                 if (inet_pton(AF_INET6, ip_addr, &sin6.sin6_addr) <= 0) {
 163                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 164                         return (-1);
 165                 }
 166         }
 167
 168         if (port_number == 0) {
 169                 syslog(LOG_ALERT, "tcpserver: no port number was specified");
 170                 return (-1);
 171         }
 172         sin6.sin6_port = htons((u_short) port_number);
 173         sin4.sin_port = htons((u_short) port_number);
 174
 175         p = getprotobyname("tcp");
 176         if (p == NULL) {
 177                 syslog(LOG_ALERT, "tcpserver: getprotobyname: %m");
 178                 return (-1);
 179         }
 180
 181         s = socket( ((ip_version == 6) ? PF_INET6 : PF_INET), SOCK_STREAM, (p->p_proto));
 182         if (s < 0) {
 183                 syslog(LOG_ALERT, "tcpserver: socket: %m");
 184                 return (-1);
 185         }
 186         // Set some socket options that make sense.
 187         i = 1;
 188         setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 189
 190         if (ip_version == 6) {
 191                 b = bind(s, (struct sockaddr *) &sin6, sizeof(sin6));
 192         }
 193         else {
 194                 b = bind(s, (struct sockaddr *) &sin4, sizeof(sin4));
 195         }
 196
 197         if (b < 0) {
 198                 syslog(LOG_ALERT, "tcpserver: bind: %m");
 199                 return (-1);
 200         }
 201
 202         fcntl(s, F_SETFL, O_NONBLOCK);
 203
 204         if (listen(s, ((queue_len >= 5) ? queue_len : 5) ) < 0) {
 205                 syslog(LOG_ALERT, "tcpserver: listen: %m");
 206                 return (-1);
 207         }
 208         return (s);
 209 }
 210
 211
 212 // Create a Unix domain socket and listen on it
 213 int ctdl_uds_server(char *sockpath, int queue_len) {
 214         struct sockaddr_un addr;
 215         int s;
 216         int i;
 217         int actual_queue_len;
 218 #ifdef HAVE_STRUCT_UCRED
 219         int passcred = 1;
 220 #endif
 221
 222         actual_queue_len = queue_len;
 223         if (actual_queue_len < 5) actual_queue_len = 5;
 224
 225         i = unlink(sockpath);
 226         if ((i != 0) && (errno != ENOENT)) {
 227                 syslog(LOG_ERR, "udsserver: %m");
 228                 return(-1);
 229         }
 230
 231         memset(&addr, 0, sizeof(addr));
 232         addr.sun_family = AF_UNIX;
 233         safestrncpy(addr.sun_path, sockpath, sizeof addr.sun_path);
 234
 235         s = socket(AF_UNIX, SOCK_STREAM, 0);
 236         if (s < 0) {
 237                 syslog(LOG_ERR, "udsserver: socket: %m");
 238                 return(-1);
 239         }
 240
 241         if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 242                 syslog(LOG_ERR, "udsserver: bind: %m");
 243                 return(-1);
 244         }
 245
 246         // set to nonblock - we need this for some obscure situations
 247         if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) {
 248                 syslog(LOG_ERR, "udsserver: fcntl: %m");
 249                 close(s);
 250                 return(-1);
 251         }
 252
 253         if (listen(s, actual_queue_len) < 0) {
 254                 syslog(LOG_ERR, "udsserver: listen: %m");
 255                 return(-1);
 256         }
 257
 258 #ifdef HAVE_STRUCT_UCRED
 259         setsockopt(s, SOL_SOCKET, SO_PASSCRED, &passcred, sizeof(passcred));
 260 #endif
 261
 262         chmod(sockpath, S_ISGID|S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IWGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH);
 263         return(s);
 264 }
 265
 266
 267 // The following functions implement output buffering on operating systems which
 268 // support it (such as Linux and various BSD flavors).
 269 #ifndef HAVE_DARWIN
 270 #ifdef TCP_CORK
 271 #       define HAVE_TCP_BUFFERING
 272 #else
 273 #       ifdef TCP_NOPUSH
 274 #               define HAVE_TCP_BUFFERING
 275 #               define TCP_CORK TCP_NOPUSH
 276 #       endif
 277 #endif // TCP_CORK
 278 #endif // HAVE_DARWIN
 279
 280 static unsigned on = 1, off = 0;
 281
 282 void buffer_output(void) {
 283 #ifdef HAVE_TCP_BUFFERING
 284 #ifdef HAVE_OPENSSL
 285         if (!CC->redirect_ssl)
 286 #endif
 287                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 288 #endif
 289 }
 290
 291 void unbuffer_output(void) {
 292 #ifdef HAVE_TCP_BUFFERING
 293 #ifdef HAVE_OPENSSL
 294         if (!CC->redirect_ssl)
 295 #endif
 296                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 297 #endif
 298 }
 299
 300 void flush_output(void) {
 301 #ifdef HAVE_TCP_BUFFERING
 302         struct CitContext *CCC = CC;
 303         setsockopt(CCC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 304         setsockopt(CCC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 305 #endif
 306 }
 307
 308
 309 // close the client socket
 310 void client_close(void) {
 311         CitContext *CCC = CC;
 312
 313         if (!CCC) return;
 314         if (CCC->client_socket <= 0) return;
 315         syslog(LOG_DEBUG, "sysdep: closing socket %d", CCC->client_socket);
 316         close(CCC->client_socket);
 317         CCC->client_socket = -1 ;
 318 }
 319
 320
 321 // Send binary data to the client.
 322 int client_write(const char *buf, int nbytes)
 323 {
 324         int bytes_written = 0;
 325         int retval;
 326 #ifndef HAVE_TCP_BUFFERING
 327         int old_buffer_len = 0;
 328 #endif
 329         fd_set wset;
 330         CitContext *Ctx;
 331         int fdflags;
 332
 333         if (nbytes < 1) return(0);
 334
 335         Ctx = CC;
 336
 337         if (Ctx->redirect_buffer != NULL) {
 338                 StrBufAppendBufPlain(Ctx->redirect_buffer,
 339                                      buf, nbytes, 0);
 340                 return 0;
 341         }
 342
 343 #ifdef HAVE_OPENSSL
 344         if (Ctx->redirect_ssl) {
 345                 client_write_ssl(buf, nbytes);
 346                 return 0;
 347         }
 348 #endif
 349         if (Ctx->client_socket == -1) return -1;
 350
 351         fdflags = fcntl(Ctx->client_socket, F_GETFL);
 352
 353         while ((bytes_written < nbytes) && (Ctx->client_socket != -1)){
 354                 if ((fdflags & O_NONBLOCK) == O_NONBLOCK) {
 355                         FD_ZERO(&wset);
 356                         FD_SET(Ctx->client_socket, &wset);
 357                         if (select(1, NULL, &wset, NULL, NULL) == -1) {
 358                                 if (errno == EINTR)
 359                                 {
 360                                         syslog(LOG_DEBUG, "sysdep: client_write(%d bytes) select() interrupted.", nbytes-bytes_written);
 361                                         if (server_shutting_down) {
 362                                                 CC->kill_me = KILLME_SELECT_INTERRUPTED;
 363                                                 return (-1);
 364                                         } else {
 365                                                 // can't trust fd's and stuff so we need to re-create them
 366                                                 continue;
 367                                         }
 368                                 } else {
 369                                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) select failed: %m", nbytes - bytes_written);
 370                                         client_close();
 371                                         Ctx->kill_me = KILLME_SELECT_FAILED;
 372                                         return -1;
 373                                 }
 374                         }
 375                 }
 376
 377                 retval = write(Ctx->client_socket, &buf[bytes_written], nbytes - bytes_written);
 378                 if (retval < 1) {
 379                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) failed: %m", nbytes - bytes_written);
 380                         client_close();
 381                         Ctx->kill_me = KILLME_WRITE_FAILED;
 382                         return -1;
 383                 }
 384                 bytes_written = bytes_written + retval;
 385         }
 386         return 0;
 387 }
 388
 389 void cputbuf(const StrBuf *Buf) {
 390         client_write(ChrPtr(Buf), StrLength(Buf));
 391 }
 392
 393
 394 // Send formatted printable data to the client.
 395 // Implemented in terms of client_write() so it's technically not sysdep...
 396 void cprintf(const char *format, ...) {
 397         va_list arg_ptr;
 398         char buf[1024];
 399
 400         va_start(arg_ptr, format);
 401         if (vsnprintf(buf, sizeof buf, format, arg_ptr) == -1)
 402                 buf[sizeof buf - 2] = '\n';
 403         client_write(buf, strlen(buf));
 404         va_end(arg_ptr);
 405 }
 406
 407
 408 // Read data from the client socket.
 409 //
 410 // sock         socket fd to read from
 411 // buf          buffer to read into
 412 // bytes        number of bytes to read
 413 // timeout      Number of seconds to wait before timing out
 414 //
 415 // Possible return values:
 416 //      1       Requested number of bytes has been read.
 417 //      0       Request timed out.
 418 //      -1      Connection is broken, or other error.
 419 int client_read_blob(StrBuf *Target, int bytes, int timeout) {
 420         CitContext *CCC=CC;
 421         const char *Error;
 422         int retval = 0;
 423
 424 #ifdef HAVE_OPENSSL
 425         if (CCC->redirect_ssl) {
 426                 retval = client_read_sslblob(Target, bytes, timeout);
 427                 if (retval < 0) {
 428                         syslog(LOG_ERR, "sysdep: client_read_blob() failed");
 429                 }
 430         }
 431         else
 432 #endif
 433         {
 434                 retval = StrBufReadBLOBBuffered(Target,
 435                                                 CCC->RecvBuf.Buf,
 436                                                 &CCC->RecvBuf.ReadWritePointer,
 437                                                 &CCC->client_socket,
 438                                                 1,
 439                                                 bytes,
 440                                                 O_TERM,
 441                                                 &Error
 442                 );
 443                 if (retval < 0) {
 444                         syslog(LOG_ERR, "sysdep: client_read_blob() failed: %s", Error);
 445                         client_close();
 446                         return retval;
 447                 }
 448         }
 449         return retval;
 450 }
 451
 452
 453 // to make client_read_random_blob() more efficient, increase buffer size.
 454 // just use in greeting function, else your buffer may be flushed
 455 void client_set_inbound_buf(long N)
 456 {
 457         CitContext *CCC=CC;
 458         FlushStrBuf(CCC->RecvBuf.Buf);
 459         ReAdjustEmptyBuf(CCC->RecvBuf.Buf, N * SIZ, N * SIZ);
 460 }
 461
 462 int client_read_random_blob(StrBuf *Target, int timeout)
 463 {
 464         CitContext *CCC=CC;
 465         int rc;
 466
 467         rc =  client_read_blob(Target, 1, timeout);
 468         if (rc > 0)
 469         {
 470                 long len;
 471                 const char *pch;
 472
 473                 len = StrLength(CCC->RecvBuf.Buf);
 474                 pch = ChrPtr(CCC->RecvBuf.Buf);
 475
 476                 if (len > 0)
 477                 {
 478                         if (CCC->RecvBuf.ReadWritePointer != NULL) {
 479                                 len -= CCC->RecvBuf.ReadWritePointer - pch;
 480                                 pch = CCC->RecvBuf.ReadWritePointer;
 481                         }
 482                         StrBufAppendBufPlain(Target, pch, len, 0);
 483                         FlushStrBuf(CCC->RecvBuf.Buf);
 484                         CCC->RecvBuf.ReadWritePointer = NULL;
 485                         return StrLength(Target);
 486                 }
 487                 return rc;
 488         }
 489         else
 490                 return rc;
 491 }
 492
 493 int client_read_to(char *buf, int bytes, int timeout)
 494 {
 495         CitContext *CCC=CC;
 496         int rc;
 497
 498         rc = client_read_blob(CCC->MigrateBuf, bytes, timeout);
 499         if (rc < 0)
 500         {
 501                 *buf = '\0';
 502                 return rc;
 503         }
 504         else
 505         {
 506                 memcpy(buf,
 507                        ChrPtr(CCC->MigrateBuf),
 508                        StrLength(CCC->MigrateBuf) + 1);
 509                 FlushStrBuf(CCC->MigrateBuf);
 510                 return rc;
 511         }
 512 }
 513
 514
 515 int HaveMoreLinesWaiting(CitContext *CCC) {
 516         if ((CCC->kill_me != 0) ||
 517             ( (CCC->RecvBuf.ReadWritePointer == NULL) &&
 518               (StrLength(CCC->RecvBuf.Buf) == 0) &&
 519               (CCC->client_socket != -1)) )
 520                 return 0;
 521         else
 522                 return 1;
 523 }
 524
 525
 526 // Read data from the client socket with default timeout.
 527 // (This is implemented in terms of client_read_to() and could be
 528 // justifiably moved out of sysdep.c)
 529 INLINE int client_read(char *buf, int bytes) {
 530         return(client_read_to(buf, bytes, CtdlGetConfigInt("c_sleeping")));
 531 }
 532
 533 int CtdlClientGetLine(StrBuf *Target) {
 534         CitContext *CCC=CC;
 535         const char *Error;
 536         int rc;
 537
 538         FlushStrBuf(Target);
 539 #ifdef HAVE_OPENSSL
 540         if (CCC->redirect_ssl) {
 541                 rc = client_readline_sslbuffer(Target, CCC->RecvBuf.Buf, &CCC->RecvBuf.ReadWritePointer, 1);
 542                 return rc;
 543         }
 544         else
 545 #endif
 546         {
 547                 rc = StrBufTCP_read_buffered_line_fast(Target,
 548                                                        CCC->RecvBuf.Buf,
 549                                                        &CCC->RecvBuf.ReadWritePointer,
 550                                                        &CCC->client_socket,
 551                                                        5,
 552                                                        1,
 553                                                        &Error
 554                 );
 555                 return rc;
 556         }
 557 }
 558
 559
 560 // Get a LF-terminated line of text from the client.
 561 // (This is implemented in terms of client_read() and could be
 562 // justifiably moved out of sysdep.c)
 563 int client_getln(char *buf, int bufsize) {
 564         int i, retval;
 565         CitContext *CCC=CC;
 566         const char *pCh;
 567
 568         retval = CtdlClientGetLine(CCC->MigrateBuf);
 569         if (retval < 0)
 570           return(retval >= 0);
 571
 572
 573         i = StrLength(CCC->MigrateBuf);
 574         pCh = ChrPtr(CCC->MigrateBuf);
 575         // Strip the trailing LF, and the trailing CR if present.
 576         if (bufsize <= i)
 577                 i = bufsize - 1;
 578         while ( (i > 0)
 579                 && ( (pCh[i - 1]==13)
 580                      || ( pCh[i - 1]==10)) ) {
 581                 i--;
 582         }
 583         memcpy(buf, pCh, i);
 584         buf[i] = 0;
 585
 586         FlushStrBuf(CCC->MigrateBuf);
 587         if (retval < 0) {
 588                 safestrncpy(&buf[i], "000", bufsize - i);
 589         }
 590         return(retval >= 0);
 591 }
 592
 593
 594 // Cleanup any contexts that are left lying around
 595 void close_masters(void) {
 596         struct ServiceFunctionHook *serviceptr;
 597         const char *Text;
 598
 599         // close all protocol master sockets
 600         for (serviceptr = ServiceHookTable; serviceptr != NULL;
 601             serviceptr = serviceptr->next ) {
 602
 603                 if (serviceptr->tcp_port > 0) {
 604                         if (serviceptr->msock == -1) {
 605                                 Text = "not closing again";
 606                         }
 607                         else {
 608                                 Text = "Closing";
 609                         }
 610                         syslog(LOG_INFO, "sysdep: %s %d listener on port %d",
 611                                Text,
 612                                serviceptr->msock,
 613                                serviceptr->tcp_port
 614                         );
 615                         serviceptr->tcp_port = 0;
 616                 }
 617
 618                 if (serviceptr->sockpath != NULL) {
 619                         if (serviceptr->msock == -1) {
 620                                 Text = "not closing again";
 621                         }
 622                         else {
 623                                 Text = "Closing";
 624                         }
 625                         syslog(LOG_INFO, "sysdep: %s %d listener on '%s'",
 626                                Text,
 627                                serviceptr->msock,
 628                                serviceptr->sockpath
 629                         );
 630                 }
 631
 632                 if (serviceptr->msock != -1) {
 633                         close(serviceptr->msock);
 634                         serviceptr->msock = -1;
 635                 }
 636
 637                 // If it's a Unix domain socket, remove the file.
 638                 if (serviceptr->sockpath != NULL) {
 639                         unlink(serviceptr->sockpath);
 640                         serviceptr->sockpath = NULL;
 641                 }
 642         }
 643 }
 644
 645
 646 // The system-dependent part of master_cleanup() - close the master socket.
 647 void sysdep_master_cleanup(void) {
 648         close_masters();
 649         context_cleanup();
 650 #ifdef HAVE_OPENSSL
 651         destruct_ssl();
 652 #endif
 653 }
 654
 655
 656
 657 pid_t current_child;
 658 void graceful_shutdown(int signum) {
 659         kill(current_child, signum);
 660         unlink(file_pid_file);
 661         exit(0);
 662 }
 663
 664 int nFireUps = 0;
 665 int nFireUpsNonRestart = 0;
 666 pid_t ForkedPid = 1;
 667
 668 // Start running as a daemon.
 669 void start_daemon(int unused) {
 670         int status = 0;
 671         pid_t child = 0;
 672         FILE *fp;
 673         int do_restart = 0;
 674         current_child = 0;
 675
 676         // Close stdin/stdout/stderr and replace them with /dev/null.
 677         // We don't just call close() because we don't want these fd's
 678         // to be reused for other files.
 679         child = fork();
 680         if (child != 0) {
 681                 exit(0);
 682         }
 683
 684         signal(SIGHUP, SIG_IGN);
 685         signal(SIGINT, SIG_IGN);
 686         signal(SIGQUIT, SIG_IGN);
 687
 688         setsid();
 689         umask(0);
 690         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
 691                 (freopen("/dev/null", "w", stdout) != stdout) ||
 692                 (freopen("/dev/null", "w", stderr) != stderr)
 693         ) {
 694                 syslog(LOG_ERR, "sysdep: unable to reopen stdio: %m");
 695         }
 696
 697         do {
 698                 current_child = fork();
 699                 signal(SIGTERM, graceful_shutdown);
 700                 if (current_child < 0) {
 701                         perror("fork");
 702                         exit(errno);
 703                 }
 704                 else if (current_child == 0) {
 705                         return; // continue starting citadel.
 706                 }
 707                 else {
 708                         fp = fopen(file_pid_file, "w");
 709                         if (fp != NULL) {
 710                                 fprintf(fp, ""F_PID_T"\n", getpid());
 711                                 fclose(fp);
 712                         }
 713                         waitpid(current_child, &status, 0);
 714                 }
 715                 nFireUpsNonRestart = nFireUps;
 716
 717                 // Exit code 0 means the watcher should exit
 718                 if (WIFEXITED(status) && (WEXITSTATUS(status) == CTDLEXIT_SHUTDOWN)) {
 719                         do_restart = 0;
 720                 }
 721
 722                 // Exit code 101-109 means the watcher should exit
 723                 else if (WIFEXITED(status) && (WEXITSTATUS(status) >= 101) && (WEXITSTATUS(status) <= 109)) {
 724                         do_restart = 0;
 725                 }
 726
 727                 // Any other exit code, or no exit code, means we should restart.
 728                 else {
 729                         do_restart = 1;
 730                         nFireUps++;
 731                         ForkedPid = current_child;
 732                 }
 733
 734         } while (do_restart);
 735
 736         unlink(file_pid_file);
 737         exit(WEXITSTATUS(status));
 738 }
 739
 740
 741 void checkcrash(void) {
 742         if (nFireUpsNonRestart != nFireUps) {
 743                 StrBuf *CrashMail;
 744                 CrashMail = NewStrBuf();
 745                 syslog(LOG_ALERT, "sysdep: posting crash message");
 746                 StrBufPrintf(CrashMail,
 747                         " \n"
 748                         " The Citadel server process (citserver) terminated unexpectedly."
 749                         "\n \n"
 750                         " This could be the result of a bug in the server program, or some external "
 751                         "factor.\n \n"
 752                         " You can obtain more information about this by enabling core dumps.\n \n"
 753                         " For more information, please see:\n \n"
 754                         " http://citadel.org/doku.php?id=faq:mastering_your_os:gdb#how.do.i.make.my.system.produce.core-files"
 755                         "\n \n"
 756
 757                         " If you have already done this, the core dump is likely to be found at %score.%d\n"
 758                         ,
 759                         ctdl_run_dir, ForkedPid);
 760                 CtdlAideMessage(ChrPtr(CrashMail), "Citadel server process terminated unexpectedly");
 761                 FreeStrBuf(&CrashMail);
 762         }
 763 }
 764
 765
 766 // Generic routine to convert a login name to a full name (gecos)
 767 // Returns nonzero if a conversion took place
 768 int convert_login(char NameToConvert[]) {
 769         struct passwd *pw;
 770         unsigned int a;
 771
 772         pw = getpwnam(NameToConvert);
 773         if (pw == NULL) {
 774                 return(0);
 775         }
 776         else {
 777                 strcpy(NameToConvert, pw->pw_gecos);
 778                 for (a=0; a<strlen(NameToConvert); ++a) {
 779                         if (NameToConvert[a] == ',') NameToConvert[a] = 0;
 780                 }
 781                 return(1);
 782         }
 783 }
 784
 785
 786 void HuntBadSession(void) {
 787         int highest;
 788         CitContext *ptr;
 789         fd_set readfds;
 790         struct timeval tv;
 791         struct ServiceFunctionHook *serviceptr;
 792
 793         // Next, add all of the client sockets
 794         begin_critical_section(S_SESSION_TABLE);
 795         for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 796                 if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 797                         continue;
 798                 // Initialize the fdset.
 799                 FD_ZERO(&readfds);
 800                 highest = 0;
 801                 tv.tv_sec = 0;          // wake up every second if no input
 802                 tv.tv_usec = 0;
 803
 804                 // Don't select on dead sessions, only truly idle ones
 805                 if (    (ptr->state == CON_IDLE)
 806                         && (ptr->kill_me == 0)
 807                         && (ptr->client_socket > 0)
 808                 ) {
 809                         FD_SET(ptr->client_socket, &readfds);
 810                         if (ptr->client_socket > highest)
 811                                 highest = ptr->client_socket;
 812
 813                         if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) && (errno == EBADF))
 814                         {
 815                                 // Gotcha!
 816                                 syslog(LOG_ERR,
 817                                        "sysdep: killing session CC[%d] bad FD: [%d] User[%s] Host[%s:%s]",
 818                                         ptr->cs_pid,
 819                                         ptr->client_socket,
 820                                         ptr->curr_user,
 821                                         ptr->cs_host,
 822                                         ptr->cs_addr
 823                                 );
 824                                 ptr->kill_me = 1;
 825                                 ptr->client_socket = -1;
 826                                 break;
 827                         }
 828                 }
 829         }
 830         end_critical_section(S_SESSION_TABLE);
 831
 832         // First, add the various master sockets to the fdset.
 833         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 834
 835                 // Initialize the fdset.
 836                 highest = 0;
 837                 tv.tv_sec = 0;          // wake up every second if no input
 838                 tv.tv_usec = 0;
 839
 840                 FD_SET(serviceptr->msock, &readfds);
 841                 if (serviceptr->msock > highest) {
 842                         highest = serviceptr->msock;
 843                 }
 844                 if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) &&
 845                     (errno == EBADF))
 846                 {
 847                         // Gotcha! server socket dead? commit suicide!
 848                         syslog(LOG_ERR, "sysdep: found bad FD: %d and its a server socket! Shutting Down!", serviceptr->msock);
 849                         server_shutting_down = 1;
 850                         break;
 851                 }
 852         }
 853 }
 854
 855
 856 // This loop just keeps going and going and going...
 857 void *worker_thread(void *blah) {
 858         int highest;
 859         CitContext *ptr;
 860         CitContext *bind_me = NULL;
 861         fd_set readfds;
 862         int retval = 0;
 863         struct timeval tv;
 864         int force_purge = 0;
 865         struct ServiceFunctionHook *serviceptr;
 866         int ssock;                      // Descriptor for client socket
 867         CitContext *con = NULL;         // Temporary context pointer
 868         int i;
 869
 870         pthread_mutex_lock(&ThreadCountMutex);
 871         ++num_workers;
 872         pthread_mutex_unlock(&ThreadCountMutex);
 873
 874         while (!server_shutting_down) {
 875
 876                 // make doubly sure we're not holding any stale db handles which might cause a deadlock
 877                 cdb_check_handles();
 878 do_select:      force_purge = 0;
 879                 bind_me = NULL;         // Which session shall we handle?
 880
 881                 // Initialize the fdset
 882                 FD_ZERO(&readfds);
 883                 highest = 0;
 884
 885                 // First, add the various master sockets to the fdset.
 886                 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 887                         FD_SET(serviceptr->msock, &readfds);
 888                         if (serviceptr->msock > highest) {
 889                                 highest = serviceptr->msock;
 890                         }
 891                 }
 892
 893                 // Next, add all of the client sockets.
 894                 begin_critical_section(S_SESSION_TABLE);
 895                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 896                         if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 897                             continue;
 898
 899                         // Don't select on dead sessions, only truly idle ones
 900                         if (    (ptr->state == CON_IDLE)
 901                                 && (ptr->kill_me == 0)
 902                                 && (ptr->client_socket > 0)
 903                         ) {
 904                                 FD_SET(ptr->client_socket, &readfds);
 905                                 if (ptr->client_socket > highest)
 906                                         highest = ptr->client_socket;
 907                         }
 908                         if ((bind_me == NULL) && (ptr->state == CON_READY)) {
 909                                 bind_me = ptr;
 910                                 ptr->state = CON_EXECUTING;
 911                                 break;
 912                         }
 913                         if ((bind_me == NULL) && (ptr->state == CON_GREETING)) {
 914                                 bind_me = ptr;
 915                                 ptr->state = CON_STARTING;
 916                                 break;
 917                         }
 918                 }
 919                 end_critical_section(S_SESSION_TABLE);
 920
 921                 if (bind_me) {
 922                         goto SKIP_SELECT;
 923                 }
 924
 925                 // If we got this far, it means that there are no sessions
 926                 // which a previous thread marked for attention, so we go
 927                 // ahead and get ready to select().
 928
 929                 if (!server_shutting_down) {
 930                         tv.tv_sec = 1;          // wake up every second if no input
 931                         tv.tv_usec = 0;
 932                         retval = select(highest + 1, &readfds, NULL, NULL, &tv);
 933                 }
 934                 else {
 935                         --num_workers;
 936                         return NULL;
 937                 }
 938
 939                 // Now figure out who made this select() unblock.
 940                 // First, check for an error or exit condition.
 941                 if (retval < 0) {
 942                         if (errno == EBADF) {
 943                                 syslog(LOG_ERR, "sysdep: select() failed: %m");
 944                                 HuntBadSession();
 945                                 goto do_select;
 946                         }
 947                         if (errno != EINTR) {
 948                                 syslog(LOG_ERR, "sysdep: exiting: %m");
 949                                 server_shutting_down = 1;
 950                                 continue;
 951                         } else {
 952                                 if (server_shutting_down) {
 953                                         --num_workers;
 954                                         return(NULL);
 955                                 }
 956                                 goto do_select;
 957                         }
 958                 }
 959                 else if (retval == 0) {
 960                         if (server_shutting_down) {
 961                                 --num_workers;
 962                                 return(NULL);
 963                         }
 964                 }
 965
 966                 // Next, check to see if it's a new client connecting on a master socket.
 967
 968                 else if ((retval > 0) && (!server_shutting_down)) for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next) {
 969
 970                         if (FD_ISSET(serviceptr->msock, &readfds)) {
 971                                 ssock = accept(serviceptr->msock, NULL, 0);
 972                                 if (ssock >= 0) {
 973                                         syslog(LOG_DEBUG, "sysdep: new client socket %d", ssock);
 974
 975                                         // The master socket is non-blocking but the client
 976                                         // sockets need to be blocking, otherwise certain
 977                                         // operations barf on FreeBSD.  Not a fatal error.
 978                                         if (fcntl(ssock, F_SETFL, 0) < 0) {
 979                                                 syslog(LOG_ERR, "sysdep: Can't set socket to blocking: %m");
 980                                         }
 981
 982                                         // New context will be created already
 983                                         // set up in the CON_EXECUTING state.
 984                                         con = CreateNewContext();
 985
 986                                         // Assign our new socket number to it.
 987                                         con->tcp_port = serviceptr->tcp_port;
 988                                         con->client_socket = ssock;
 989                                         con->h_command_function = serviceptr->h_command_function;
 990                                         con->h_async_function = serviceptr->h_async_function;
 991                                         con->h_greeting_function = serviceptr->h_greeting_function;
 992                                         con->ServiceName = serviceptr->ServiceName;
 993
 994                                         // Connections on a local client are always from the same host
 995                                         if (serviceptr->sockpath != NULL) {
 996                                                 con->is_local_client = 1;
 997                                         }
 998
 999                                         // Set the SO_REUSEADDR socket option
1000                                         i = 1;
1001                                         setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
1002                                         con->state = CON_GREETING;
1003                                         retval--;
1004                                         if (retval == 0)
1005                                                 break;
1006                                 }
1007                         }
1008                 }
1009
1010                 // It must be a client socket.  Find a context that has data
1011                 // waiting on its socket *and* is in the CON_IDLE state.  Any
1012                 // active sockets other than our chosen one are marked as
1013                 // CON_READY so the next thread that comes around can just bind
1014                 // to one without having to select() again.
1015                 begin_critical_section(S_SESSION_TABLE);
1016                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
1017                         int checkfd = ptr->client_socket;
1018                         if ((checkfd != -1) && (ptr->state == CON_IDLE) ){
1019                                 if (FD_ISSET(checkfd, &readfds)) {
1020                                         ptr->input_waiting = 1;
1021                                         if (!bind_me) {
1022                                                 bind_me = ptr;  // I choose you!
1023                                                 bind_me->state = CON_EXECUTING;
1024                                         }
1025                                         else {
1026                                                 ptr->state = CON_READY;
1027                                         }
1028                                 } else if ((ptr->is_async) && (ptr->async_waiting) && (ptr->h_async_function)) {
1029                                         if (!bind_me) {
1030                                                 bind_me = ptr;  // I choose you!
1031                                                 bind_me->state = CON_EXECUTING;
1032                                         }
1033                                         else {
1034                                                 ptr->state = CON_READY;
1035                                         }
1036                                 }
1037                         }
1038                 }
1039                 end_critical_section(S_SESSION_TABLE);
1040
1041 SKIP_SELECT:
1042                 // We're bound to a session
1043                 pthread_mutex_lock(&ThreadCountMutex);
1044                 ++active_workers;
1045                 pthread_mutex_unlock(&ThreadCountMutex);
1046
1047                 if (bind_me != NULL) {
1048                         become_session(bind_me);
1049
1050                         if (bind_me->state == CON_STARTING) {
1051                                 bind_me->state = CON_EXECUTING;
1052                                 begin_session(bind_me);
1053                                 bind_me->h_greeting_function();
1054                         }
1055                         // If the client has sent a command, execute it.
1056                         if (CC->input_waiting) {
1057                                 CC->h_command_function();
1058
1059                                 while (HaveMoreLinesWaiting(CC))
1060                                        CC->h_command_function();
1061
1062                                 CC->input_waiting = 0;
1063                         }
1064
1065                         // If there are asynchronous messages waiting and the client supports it, do those now
1066                         if ((CC->is_async) && (CC->async_waiting) && (CC->h_async_function != NULL)) {
1067                                 CC->h_async_function();
1068                                 CC->async_waiting = 0;
1069                         }
1070
1071                         force_purge = CC->kill_me;
1072                         become_session(NULL);
1073                         bind_me->state = CON_IDLE;
1074                 }
1075
1076                 dead_session_purge(force_purge);
1077                 do_housekeeping();
1078
1079                 pthread_mutex_lock(&ThreadCountMutex);
1080                 --active_workers;
1081                 if ((active_workers + CtdlGetConfigInt("c_min_workers") < num_workers) &&
1082                     (num_workers > CtdlGetConfigInt("c_min_workers")))
1083                 {
1084                         num_workers--;
1085                         pthread_mutex_unlock(&ThreadCountMutex);
1086                         return (NULL);
1087                 }
1088                 pthread_mutex_unlock(&ThreadCountMutex);
1089         }
1090
1091         // If control reaches this point, the server is shutting down
1092         pthread_mutex_lock(&ThreadCountMutex);
1093         --num_workers;
1094         pthread_mutex_unlock(&ThreadCountMutex);
1095         return(NULL);
1096 }
1097
1098
1099 // SyslogFacility()
1100 // Translate text facility name to syslog.h defined value.
1101 int SyslogFacility(char *name)
1102 {
1103         int i;
1104         struct
1105         {
1106                 int facility;
1107                 char *name;
1108         }   facTbl[] =
1109         {
1110                 {   LOG_KERN,   "kern"          },
1111                 {   LOG_USER,   "user"          },
1112                 {   LOG_MAIL,   "mail"          },
1113                 {   LOG_DAEMON, "daemon"        },
1114                 {   LOG_AUTH,   "auth"          },
1115                 {   LOG_SYSLOG, "syslog"        },
1116                 {   LOG_LPR,    "lpr"           },
1117                 {   LOG_NEWS,   "news"          },
1118                 {   LOG_UUCP,   "uucp"          },
1119                 {   LOG_LOCAL0, "local0"        },
1120                 {   LOG_LOCAL1, "local1"        },
1121                 {   LOG_LOCAL2, "local2"        },
1122                 {   LOG_LOCAL3, "local3"        },
1123                 {   LOG_LOCAL4, "local4"        },
1124                 {   LOG_LOCAL5, "local5"        },
1125                 {   LOG_LOCAL6, "local6"        },
1126                 {   LOG_LOCAL7, "local7"        },
1127                 {   0,            NULL          }
1128         };
1129         for(i = 0; facTbl[i].name != NULL; i++) {
1130                 if(!strcasecmp(name, facTbl[i].name))
1131                         return facTbl[i].facility;
1132         }
1133         return LOG_DAEMON;
1134 }