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