citadel/server/sysdep.c

   1 // This started as a portability layer, but then everything got more standard.
   2 // Most of it handles network communication.
   3 //
   4 // Copyright (c) 1987-2023 by the citadel.org team
   5 //
   6 // This program is open source software.  Use, duplication, or disclosure
   7 // is subject to the terms of the GNU General Public License, version 3.
   8
   9 #include "sysdep.h"
  10 #include <stdlib.h>
  11 #include <unistd.h>
  12 #include <sys/stat.h>
  13 #include <errno.h>
  14 #include <signal.h>
  15 #include <stdio.h>
  16 #include <syslog.h>
  17 #include <sys/syslog.h>
  18 #include <execinfo.h>
  19 #include <netdb.h>
  20 #include <sys/un.h>
  21 #include <sys/types.h>
  22 #include <sys/socket.h>
  23 #include <netinet/in.h>
  24 #include <arpa/inet.h>
  25 #include <netinet/tcp.h>
  26 #include <arpa/inet.h>
  27 #define SHOW_ME_VAPPEND_PRINTF
  28 #include <libcitadel.h>
  29 #include "citserver.h"
  30 #include "config.h"
  31 #include "ctdl_module.h"
  32 #include "sysdep_decls.h"
  33 #include "modules/crypto/serv_crypto.h" // Needed for init_ssl, client_write_ssl, client_read_ssl
  34 #include "housekeeping.h"
  35 #include "context.h"
  36
  37 // Signal handler to shut down the server.
  38 volatile int exit_signal = 0;
  39 volatile int shutdown_and_halt = 0;
  40 volatile int restart_server = 0;
  41 volatile int running_as_daemon = 0;
  42
  43
  44 static RETSIGTYPE signal_cleanup(int signum) {
  45         syslog(LOG_DEBUG, "sysdep: caught signal %d", signum);
  46         signal(SIGINT, SIG_DFL);
  47         signal(SIGHUP, SIG_DFL);
  48         signal(SIGTERM, SIG_DFL);
  49         signal(SIGSEGV, SIG_DFL);
  50         exit_signal = signum;
  51         server_shutting_down = 1;
  52         master_cleanup(signum);
  53 }
  54
  55
  56 // Some initialization stuff...
  57 void init_sysdep(void) {
  58         sigset_t set;
  59
  60         // Avoid vulnerabilities related to FD_SETSIZE if we can.
  61 #ifdef FD_SETSIZE
  62 #ifdef RLIMIT_NOFILE
  63         struct rlimit rl;
  64         getrlimit(RLIMIT_NOFILE, &rl);
  65         rl.rlim_cur = FD_SETSIZE;
  66         rl.rlim_max = FD_SETSIZE;
  67         setrlimit(RLIMIT_NOFILE, &rl);
  68 #endif
  69 #endif
  70
  71         // If we've got OpenSSL, we're going to use it.
  72 #ifdef HAVE_OPENSSL
  73         init_ssl();
  74 #endif
  75
  76         if (pthread_key_create(&MyConKey, NULL) != 0) {                         // TSD for sessions
  77                 syslog(LOG_CRIT, "sysdep: can't create TSD key: %m");
  78                 exit(CTDLEXIT_THREAD);
  79         }
  80
  81         // Interript, hangup, and terminate signals should cause the server to shut down.
  82         sigemptyset(&set);
  83         sigaddset(&set, SIGINT);
  84         sigaddset(&set, SIGHUP);
  85         sigaddset(&set, SIGTERM);
  86         sigaddset(&set, SIGSEGV);
  87         sigprocmask(SIG_UNBLOCK, &set, NULL);
  88
  89         signal(SIGINT, signal_cleanup);
  90         signal(SIGHUP, signal_cleanup);
  91         signal(SIGTERM, signal_cleanup);
  92         signal(SIGSEGV, signal_cleanup);
  93
  94         // Do not shut down the server on broken pipe signals, otherwise the
  95         // whole Citadel service would come down whenever a single client
  96         // socket breaks.
  97         signal(SIGPIPE, SIG_IGN);
  98 }
  99
 100
 101 // This is a generic function to set up a master socket for listening on
 102 // a TCP port.  The server shuts down if the bind fails.  (IPv4/IPv6 version)
 103 //
 104 // ip_addr      IP address to bind
 105 // port_number  port number to bind
 106 // queue_len    number of incoming connections to allow in the queue
 107 int ctdl_tcp_server(char *ip_addr, int port_number, int queue_len) {
 108         struct protoent *p;
 109         struct sockaddr_in6 sin6;
 110         struct sockaddr_in sin4;
 111         int s, i, b;
 112         int ip_version = 6;
 113
 114         memset(&sin6, 0, sizeof(sin6));
 115         memset(&sin4, 0, sizeof(sin4));
 116         sin6.sin6_family = AF_INET6;
 117         sin4.sin_family = AF_INET;
 118
 119         if (    (ip_addr == NULL)                                                       // any IPv6
 120                 || (IsEmptyStr(ip_addr))
 121                 || (!strcmp(ip_addr, "*"))
 122                 || (!strcmp(ip_addr, "::"))
 123         ) {
 124                 ip_version = 6;
 125                 sin6.sin6_addr = in6addr_any;
 126         }
 127         else if (!strcmp(ip_addr, "0.0.0.0")) {                                         // any IPv4
 128                 ip_version = 4;
 129                 sin4.sin_addr.s_addr = INADDR_ANY;
 130         }
 131         else if ((strchr(ip_addr, '.')) && (!strchr(ip_addr, ':'))) {                   // specific IPv4
 132                 ip_version = 4;
 133                 if (inet_pton(AF_INET, ip_addr, &sin4.sin_addr) <= 0) {
 134                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 135                         return (-1);
 136                 }
 137         }
 138         else {                                                                          // specific IPv6
 139                 ip_version = 6;
 140                 if (inet_pton(AF_INET6, ip_addr, &sin6.sin6_addr) <= 0) {
 141                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 142                         return (-1);
 143                 }
 144         }
 145
 146         if (port_number == 0) {
 147                 syslog(LOG_ALERT, "tcpserver: no port number was specified");
 148                 return (-1);
 149         }
 150         sin6.sin6_port = htons((u_short) port_number);
 151         sin4.sin_port = htons((u_short) port_number);
 152
 153         p = getprotobyname("tcp");
 154         if (p == NULL) {
 155                 syslog(LOG_ALERT, "tcpserver: getprotobyname: %m");
 156                 return (-1);
 157         }
 158
 159         s = socket( ((ip_version == 6) ? PF_INET6 : PF_INET), SOCK_STREAM, (p->p_proto));
 160         if (s < 0) {
 161                 syslog(LOG_ALERT, "tcpserver: socket: %m");
 162                 return (-1);
 163         }
 164         // Set some socket options that make sense.
 165         i = 1;
 166         setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 167
 168         if (ip_version == 6) {
 169                 b = bind(s, (struct sockaddr *) &sin6, sizeof(sin6));
 170         }
 171         else {
 172                 b = bind(s, (struct sockaddr *) &sin4, sizeof(sin4));
 173         }
 174
 175         if (b < 0) {
 176                 syslog(LOG_ALERT, "tcpserver: bind: %m");
 177                 return (-1);
 178         }
 179
 180         fcntl(s, F_SETFL, O_NONBLOCK);
 181
 182         if (listen(s, ((queue_len >= 5) ? queue_len : 5) ) < 0) {
 183                 syslog(LOG_ALERT, "tcpserver: listen: %m");
 184                 return (-1);
 185         }
 186         return (s);
 187 }
 188
 189
 190 // Create a Unix domain socket and listen on it
 191 int ctdl_uds_server(char *sockpath, int queue_len) {
 192         struct sockaddr_un addr;
 193         int s;
 194         int i;
 195         int actual_queue_len;
 196 #ifdef HAVE_STRUCT_UCRED
 197         int passcred = 1;
 198 #endif
 199
 200         actual_queue_len = queue_len;
 201         if (actual_queue_len < 5) actual_queue_len = 5;
 202
 203         i = unlink(sockpath);
 204         if ((i != 0) && (errno != ENOENT)) {
 205                 syslog(LOG_ERR, "udsserver: %m");
 206                 return(-1);
 207         }
 208
 209         memset(&addr, 0, sizeof(addr));
 210         addr.sun_family = AF_UNIX;
 211         safestrncpy(addr.sun_path, sockpath, sizeof addr.sun_path);
 212
 213         s = socket(AF_UNIX, SOCK_STREAM, 0);
 214         if (s < 0) {
 215                 syslog(LOG_ERR, "udsserver: socket: %m");
 216                 return(-1);
 217         }
 218
 219         if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 220                 syslog(LOG_ERR, "udsserver: bind: %m");
 221                 return(-1);
 222         }
 223
 224         // set to nonblock - we need this for some obscure situations
 225         if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) {
 226                 syslog(LOG_ERR, "udsserver: fcntl: %m");
 227                 close(s);
 228                 return(-1);
 229         }
 230
 231         if (listen(s, actual_queue_len) < 0) {
 232                 syslog(LOG_ERR, "udsserver: listen: %m");
 233                 return(-1);
 234         }
 235
 236 #ifdef HAVE_STRUCT_UCRED
 237         setsockopt(s, SOL_SOCKET, SO_PASSCRED, &passcred, sizeof(passcred));
 238 #endif
 239
 240         chmod(sockpath, S_ISGID|S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IWGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH);
 241         return(s);
 242 }
 243
 244
 245 // The following functions implement output buffering on operating systems which
 246 // support it (such as Linux and various BSD flavors).
 247 #ifndef HAVE_DARWIN
 248 #ifdef TCP_CORK
 249 #       define HAVE_TCP_BUFFERING
 250 #else
 251 #       ifdef TCP_NOPUSH
 252 #               define HAVE_TCP_BUFFERING
 253 #               define TCP_CORK TCP_NOPUSH
 254 #       endif
 255 #endif // TCP_CORK
 256 #endif // HAVE_DARWIN
 257
 258 static unsigned on = 1, off = 0;
 259
 260 void buffer_output(void) {
 261 #ifdef HAVE_TCP_BUFFERING
 262 #ifdef HAVE_OPENSSL
 263         if (!CC->redirect_ssl)
 264 #endif
 265                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 266 #endif
 267 }
 268
 269 void unbuffer_output(void) {
 270 #ifdef HAVE_TCP_BUFFERING
 271 #ifdef HAVE_OPENSSL
 272         if (!CC->redirect_ssl)
 273 #endif
 274                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 275 #endif
 276 }
 277
 278 void flush_output(void) {
 279 #ifdef HAVE_TCP_BUFFERING
 280         setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 281         setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 282 #endif
 283 }
 284
 285
 286 // close the client socket
 287 void client_close(void) {
 288         if (!CC) return;
 289         if (CC->client_socket <= 0) return;
 290         syslog(LOG_DEBUG, "sysdep: closing socket %d", CC->client_socket);
 291         close(CC->client_socket);
 292         CC->client_socket = -1 ;
 293 }
 294
 295
 296 // Send binary data to the client.
 297 int client_write(const char *buf, int nbytes) {
 298         int bytes_written = 0;
 299         int retval;
 300 #ifndef HAVE_TCP_BUFFERING
 301         int old_buffer_len = 0;
 302 #endif
 303         fd_set wset;
 304         CitContext *Ctx;
 305         int fdflags;
 306
 307         if (nbytes < 1) return(0);
 308
 309         Ctx = CC;
 310         if (Ctx->redirect_buffer != NULL) {
 311                 StrBufAppendBufPlain(Ctx->redirect_buffer, buf, nbytes, 0);
 312                 return 0;
 313         }
 314
 315 #ifdef HAVE_OPENSSL
 316         if (Ctx->redirect_ssl) {
 317                 client_write_ssl(buf, nbytes);
 318                 return 0;
 319         }
 320 #endif
 321         if (Ctx->client_socket == -1) return -1;
 322
 323         fdflags = fcntl(Ctx->client_socket, F_GETFL);
 324
 325         while ((bytes_written < nbytes) && (Ctx->client_socket != -1)){
 326                 if ((fdflags & O_NONBLOCK) == O_NONBLOCK) {
 327                         FD_ZERO(&wset);
 328                         FD_SET(Ctx->client_socket, &wset);
 329                         if (select(1, NULL, &wset, NULL, NULL) == -1) {
 330                                 if (errno == EINTR) {
 331                                         syslog(LOG_DEBUG, "sysdep: client_write(%d bytes) select() interrupted.", nbytes-bytes_written);
 332                                         if (server_shutting_down) {
 333                                                 CC->kill_me = KILLME_SELECT_INTERRUPTED;
 334                                                 return (-1);
 335                                         }
 336                                         else {
 337                                                 // can't trust fd's and stuff so we need to re-create them
 338                                                 continue;
 339                                         }
 340                                 }
 341                                 else {
 342                                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) select failed: %m", nbytes - bytes_written);
 343                                         client_close();
 344                                         Ctx->kill_me = KILLME_SELECT_FAILED;
 345                                         return -1;
 346                                 }
 347                         }
 348                 }
 349
 350                 retval = write(Ctx->client_socket, &buf[bytes_written], nbytes - bytes_written);
 351                 if (retval < 1) {
 352                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) failed: %m", nbytes - bytes_written);
 353                         client_close();
 354                         Ctx->kill_me = KILLME_WRITE_FAILED;
 355                         return -1;
 356                 }
 357                 bytes_written = bytes_written + retval;
 358         }
 359         return 0;
 360 }
 361
 362
 363 void cputbuf(const StrBuf *Buf) {
 364         client_write(ChrPtr(Buf), StrLength(Buf));
 365 }
 366
 367
 368 // Send formatted printable data to the client.
 369 // Implemented in terms of client_write() so it's technically not sysdep...
 370 void cprintf(const char *format, ...) {
 371         va_list arg_ptr;
 372         char buf[1024];
 373         int rc;
 374
 375         va_start(arg_ptr, format);
 376         rc = vsnprintf(buf, sizeof buf, format, arg_ptr);
 377         if (rc < 0) {
 378                 syslog(LOG_ERR,"Console output error occured. Format: %s",format);
 379         } else {
 380                 if (rc >= sizeof buf) {
 381                         // Output was truncated.
 382                         // Chop at the end of the buffer
 383                         buf[sizeof buf - 2] = '\n';
 384                         buf[sizeof buf - 1] = 0;
 385                 }
 386                 client_write(buf, strlen(buf));
 387         }
 388         va_end(arg_ptr);
 389 }
 390
 391
 392 // Read data from the client socket.
 393 //
 394 // sock         socket fd to read from
 395 // buf          buffer to read into
 396 // bytes        number of bytes to read
 397 // timeout      Number of seconds to wait before timing out
 398 //
 399 // Possible return values:
 400 //      1       Requested number of bytes has been read.
 401 //      0       Request timed out.
 402 //      -1      Connection is broken, or other error.
 403 int client_read_blob(StrBuf *Target, int bytes, int timeout) {
 404         const char *Error;
 405         int retval = 0;
 406
 407 #ifdef HAVE_OPENSSL
 408         if (CC->redirect_ssl) {
 409                 retval = client_read_sslblob(Target, bytes, timeout);
 410                 if (retval < 0) {
 411                         syslog(LOG_ERR, "sysdep: client_read_blob() failed");
 412                 }
 413         }
 414         else
 415 #endif
 416         {
 417                 retval = StrBufReadBLOBBuffered(Target,
 418                                                 CC->RecvBuf.Buf,
 419                                                 &CC->RecvBuf.ReadWritePointer,
 420                                                 &CC->client_socket,
 421                                                 1,
 422                                                 bytes,
 423                                                 O_TERM,
 424                                                 &Error
 425                 );
 426                 if (retval < 0) {
 427                         syslog(LOG_ERR, "sysdep: client_read_blob() failed: %s", Error);
 428                         client_close();
 429                         return retval;
 430                 }
 431         }
 432         return retval;
 433 }
 434
 435
 436 // to make client_read_random_blob() more efficient, increase buffer size.
 437 // just use in greeting function, else your buffer may be flushed
 438 void client_set_inbound_buf(long N) {
 439         FlushStrBuf(CC->RecvBuf.Buf);
 440         ReAdjustEmptyBuf(CC->RecvBuf.Buf, N * SIZ, N * SIZ);
 441 }
 442
 443
 444 int client_read_random_blob(StrBuf *Target, int timeout) {
 445         int rc;
 446
 447         rc =  client_read_blob(Target, 1, timeout);
 448         if (rc > 0) {
 449                 long len;
 450                 const char *pch;
 451
 452                 len = StrLength(CC->RecvBuf.Buf);
 453                 pch = ChrPtr(CC->RecvBuf.Buf);
 454
 455                 if (len > 0) {
 456                         if (CC->RecvBuf.ReadWritePointer != NULL) {
 457                                 len -= CC->RecvBuf.ReadWritePointer - pch;
 458                                 pch = CC->RecvBuf.ReadWritePointer;
 459                         }
 460                         StrBufAppendBufPlain(Target, pch, len, 0);
 461                         FlushStrBuf(CC->RecvBuf.Buf);
 462                         CC->RecvBuf.ReadWritePointer = NULL;
 463                         return StrLength(Target);
 464                 }
 465                 return rc;
 466         }
 467         else
 468                 return rc;
 469 }
 470
 471
 472 int client_read_to(char *buf, int bytes, int timeout) {
 473         int rc;
 474
 475         rc = client_read_blob(CC->MigrateBuf, bytes, timeout);
 476         if (rc < 0) {
 477                 *buf = '\0';
 478                 return rc;
 479         }
 480         else {
 481                 memcpy(buf,
 482                        ChrPtr(CC->MigrateBuf),
 483                        StrLength(CC->MigrateBuf) + 1);
 484                 FlushStrBuf(CC->MigrateBuf);
 485                 return rc;
 486         }
 487 }
 488
 489
 490 int HaveMoreLinesWaiting(CitContext *ctx) {
 491         if (    (ctx->kill_me != 0)
 492                 || ( (ctx->RecvBuf.ReadWritePointer == NULL)
 493                 && (StrLength(ctx->RecvBuf.Buf) == 0)
 494                 && (ctx->client_socket != -1))
 495         )
 496                 return 0;
 497         else
 498                 return 1;
 499 }
 500
 501
 502 // Read data from the client socket with default timeout.
 503 // (This is implemented in terms of client_read_to() and could be
 504 // justifiably moved out of sysdep.c)
 505 INLINE int client_read(char *buf, int bytes) {
 506         return(client_read_to(buf, bytes, CtdlGetConfigInt("c_sleeping")));
 507 }
 508
 509
 510 int CtdlClientGetLine(StrBuf *Target) {
 511         const char *Error;
 512         int rc;
 513
 514         FlushStrBuf(Target);
 515 #ifdef HAVE_OPENSSL
 516         if (CC->redirect_ssl) {
 517                 rc = client_readline_sslbuffer(Target, CC->RecvBuf.Buf, &CC->RecvBuf.ReadWritePointer, 1);
 518                 return rc;
 519         }
 520         else
 521 #endif
 522         {
 523                 rc = StrBufTCP_read_buffered_line_fast(Target,
 524                                                        CC->RecvBuf.Buf,
 525                                                        &CC->RecvBuf.ReadWritePointer,
 526                                                        &CC->client_socket,
 527                                                        5,
 528                                                        1,
 529                                                        &Error
 530                 );
 531                 return rc;
 532         }
 533 }
 534
 535
 536 // Get a LF-terminated line of text from the client.
 537 // (This is implemented in terms of client_read() and could be
 538 // justifiably moved out of sysdep.c)
 539 int client_getln(char *buf, int bufsize) {
 540         int i, retval;
 541         const char *pCh;
 542
 543         retval = CtdlClientGetLine(CC->MigrateBuf);
 544         if (retval < 0)
 545           return(retval >= 0);
 546
 547
 548         i = StrLength(CC->MigrateBuf);
 549         pCh = ChrPtr(CC->MigrateBuf);
 550         // Strip the trailing LF, and the trailing CR if present.
 551         if (bufsize <= i)
 552                 i = bufsize - 1;
 553         while ( (i > 0)
 554                 && ( (pCh[i - 1]==13)
 555                      || ( pCh[i - 1]==10)) ) {
 556                 i--;
 557         }
 558         memcpy(buf, pCh, i);
 559         buf[i] = 0;
 560
 561         FlushStrBuf(CC->MigrateBuf);
 562         if (retval < 0) {
 563                 safestrncpy(&buf[i], "000", bufsize - i);
 564         }
 565         return(retval >= 0);
 566 }
 567
 568
 569 pid_t current_child;
 570 void supervisor_process_shutdown(int signum) {
 571         kill(current_child, signum);
 572         unlink(file_pid_file);
 573         exit(0);
 574 }
 575
 576 int nFireUps = 0;
 577 int nFireUpsNonRestart = 0;
 578 pid_t ForkedPid = 1;
 579
 580 // Start running as a daemon.
 581 void start_daemon(int unused) {
 582         int status = 0;
 583         pid_t child = 0;
 584         FILE *fp;
 585         int do_restart = 0;
 586         current_child = 0;
 587
 588         // Close stdin/stdout/stderr and replace them with /dev/null.
 589         // We don't just call close() because we don't want these fd's
 590         // to be reused for other files.
 591         child = fork();
 592         if (child != 0) {
 593                 exit(0);
 594         }
 595
 596         signal(SIGHUP, SIG_IGN);
 597         signal(SIGINT, SIG_IGN);
 598         signal(SIGQUIT, SIG_IGN);
 599
 600         setsid();
 601         umask(0);
 602         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
 603                 (freopen("/dev/null", "w", stdout) != stdout) ||
 604                 (freopen("/dev/null", "w", stderr) != stderr)
 605         ) {
 606                 syslog(LOG_ERR, "sysdep: unable to reopen stdio: %m");
 607         }
 608
 609         do {
 610                 current_child = fork();
 611                 signal(SIGTERM, supervisor_process_shutdown);
 612                 if (current_child < 0) {
 613                         perror("fork");
 614                         exit(errno);
 615                 }
 616                 else if (current_child == 0) {
 617                         return; // continue starting citadel.
 618                 }
 619                 else {
 620                         fp = fopen(file_pid_file, "w");
 621                         if (fp != NULL) {
 622                                 fprintf(fp, ""F_PID_T"\n", getpid());
 623                                 fclose(fp);
 624                         }
 625                         waitpid(current_child, &status, 0);
 626                 }
 627                 nFireUpsNonRestart = nFireUps;
 628
 629                 // Exit code 0 means the watcher should exit
 630                 if (WIFEXITED(status) && (WEXITSTATUS(status) == CTDLEXIT_SHUTDOWN)) {
 631                         do_restart = 0;
 632                 }
 633
 634                 // Exit code 101-109 means the watcher should exit
 635                 else if (WIFEXITED(status) && (WEXITSTATUS(status) >= 101) && (WEXITSTATUS(status) <= 109)) {
 636                         do_restart = 0;
 637                 }
 638
 639                 // Any other exit code, or no exit code, means we should restart.
 640                 else {
 641                         do_restart = 1;
 642                         nFireUps++;
 643                         ForkedPid = current_child;
 644                 }
 645
 646         } while (do_restart);
 647
 648         unlink(file_pid_file);
 649         exit(WEXITSTATUS(status));
 650 }
 651
 652
 653 void checkcrash(void) {
 654         if (nFireUpsNonRestart != nFireUps) {
 655                 StrBuf *CrashMail;
 656                 CrashMail = NewStrBuf();
 657                 syslog(LOG_ALERT, "sysdep: posting crash message");
 658                 StrBufPrintf(CrashMail,
 659                         " \n"
 660                         " The Citadel server process (citserver) terminated unexpectedly."
 661                         "\n \n"
 662                         " This could be the result of a bug in the server program, or some external "
 663                         "factor.\n \n"
 664                         " You can obtain more information about this by enabling core dumps.\n \n"
 665                         " For more information, please see:\n \n"
 666                         " http://citadel.org/doku.php?id=faq:mastering_your_os:gdb#how.do.i.make.my.system.produce.core-files"
 667                         "\n \n"
 668
 669                         " If you have already done this, the core dump is likely to be found at %score.%d\n"
 670                         ,
 671                         ctdl_run_dir, ForkedPid);
 672                 CtdlAideMessage(ChrPtr(CrashMail), "Citadel server process terminated unexpectedly");
 673                 FreeStrBuf(&CrashMail);
 674         }
 675 }
 676
 677
 678 // Generic routine to convert a login name to a full name (gecos)
 679 // Returns nonzero if a conversion took place
 680 int convert_login(char NameToConvert[]) {
 681         struct passwd *pw;
 682         unsigned int a;
 683
 684         pw = getpwnam(NameToConvert);
 685         if (pw == NULL) {
 686                 return(0);
 687         }
 688         else {
 689                 strcpy(NameToConvert, pw->pw_gecos);
 690                 for (a=0; a<strlen(NameToConvert); ++a) {
 691                         if (NameToConvert[a] == ',') NameToConvert[a] = 0;
 692                 }
 693                 return(1);
 694         }
 695 }
 696
 697
 698 void HuntBadSession(void) {
 699         int highest;
 700         CitContext *ptr;
 701         fd_set readfds;
 702         struct timeval tv;
 703         struct ServiceFunctionHook *serviceptr;
 704
 705         // Next, add all of the client sockets
 706         begin_critical_section(S_SESSION_TABLE);
 707         for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 708                 if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 709                         continue;
 710                 // Initialize the fdset.
 711                 FD_ZERO(&readfds);
 712                 highest = 0;
 713                 tv.tv_sec = 0;          // wake up every second if no input
 714                 tv.tv_usec = 0;
 715
 716                 // Don't select on dead sessions, only truly idle ones
 717                 if (    (ptr->state == CON_IDLE)
 718                         && (ptr->kill_me == 0)
 719                         && (ptr->client_socket > 0)
 720                 ) {
 721                         FD_SET(ptr->client_socket, &readfds);
 722                         if (ptr->client_socket > highest)
 723                                 highest = ptr->client_socket;
 724
 725                         if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) && (errno == EBADF)) {
 726                                 // Gotcha!
 727                                 syslog(LOG_ERR,
 728                                        "sysdep: killing session CC[%d] bad FD: [%d] User[%s] Host[%s:%s]",
 729                                         ptr->cs_pid,
 730                                         ptr->client_socket,
 731                                         ptr->curr_user,
 732                                         ptr->cs_host,
 733                                         ptr->cs_addr
 734                                 );
 735                                 ptr->kill_me = 1;
 736                                 ptr->client_socket = -1;
 737                                 break;
 738                         }
 739                 }
 740         }
 741         end_critical_section(S_SESSION_TABLE);
 742
 743         // First, add the various master sockets to the fdset.
 744         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 745
 746                 // Initialize the fdset.
 747                 highest = 0;
 748                 tv.tv_sec = 0;          // wake up every second if no input
 749                 tv.tv_usec = 0;
 750
 751                 FD_SET(serviceptr->msock, &readfds);
 752                 if (serviceptr->msock > highest) {
 753                         highest = serviceptr->msock;
 754                 }
 755                 if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) && (errno == EBADF)) {
 756                         // Gotcha! server socket dead? commit suicide!
 757                         syslog(LOG_ERR, "sysdep: found bad FD: %d and its a server socket! Shutting Down!", serviceptr->msock);
 758                         server_shutting_down = 1;
 759                         break;
 760                 }
 761         }
 762 }
 763
 764
 765 // Main server loop
 766 // select() can wake up on any of the following conditions:
 767 // 1. A new client connection on a master socket
 768 // 2. Received data on a client socket
 769 // 3. A timer event
 770 // That's why we are blocking on select() and not accept().
 771 void *worker_thread(void *blah) {
 772         int highest;
 773         CitContext *ptr;
 774         CitContext *bind_me = NULL;
 775         fd_set readfds;
 776         int retval = 0;
 777         struct timeval tv;
 778         int force_purge = 0;
 779         struct ServiceFunctionHook *serviceptr;
 780         int ssock;                      // Descriptor for client socket
 781         CitContext *con = NULL;         // Temporary context pointer
 782         int i;
 783
 784         pthread_mutex_lock(&ThreadCountMutex);
 785         ++num_workers;
 786         pthread_mutex_unlock(&ThreadCountMutex);
 787
 788         while (!server_shutting_down) {
 789
 790                 // make doubly sure we're not holding any stale db handles which might cause a deadlock
 791                 cdb_check_handles();
 792 do_select:      force_purge = 0;
 793                 bind_me = NULL;         // Which session shall we handle?
 794
 795                 // Initialize the fdset
 796                 FD_ZERO(&readfds);
 797                 highest = 0;
 798
 799                 // First, add the various master sockets to the fdset.
 800                 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 801                         FD_SET(serviceptr->msock, &readfds);
 802                         if (serviceptr->msock > highest) {
 803                                 highest = serviceptr->msock;
 804                         }
 805                 }
 806
 807                 // Next, add all of the client sockets.
 808                 begin_critical_section(S_SESSION_TABLE);
 809                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 810                         if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 811                             continue;
 812
 813                         // Don't select on dead sessions, only truly idle ones
 814                         if (    (ptr->state == CON_IDLE)
 815                                 && (ptr->kill_me == 0)
 816                                 && (ptr->client_socket > 0)
 817                         ) {
 818                                 FD_SET(ptr->client_socket, &readfds);
 819                                 if (ptr->client_socket > highest)
 820                                         highest = ptr->client_socket;
 821                         }
 822                         if ((bind_me == NULL) && (ptr->state == CON_READY)) {
 823                                 bind_me = ptr;
 824                                 ptr->state = CON_EXECUTING;
 825                                 break;
 826                         }
 827                         if ((bind_me == NULL) && (ptr->state == CON_GREETING)) {
 828                                 bind_me = ptr;
 829                                 ptr->state = CON_STARTING;
 830                                 break;
 831                         }
 832                 }
 833                 end_critical_section(S_SESSION_TABLE);
 834
 835                 if (bind_me) {
 836                         goto SKIP_SELECT;
 837                 }
 838
 839                 // If we got this far, it means that there are no sessions
 840                 // which a previous thread marked for attention, so we go
 841                 // ahead and get ready to select().
 842
 843                 if (!server_shutting_down) {
 844                         tv.tv_sec = 1;          // wake up every second if no input
 845                         tv.tv_usec = 0;
 846                         retval = select(highest + 1, &readfds, NULL, NULL, &tv);
 847                 }
 848                 else {
 849                         --num_workers;
 850                         return NULL;
 851                 }
 852
 853                 // Now figure out who made this select() unblock.
 854                 // First, check for an error or exit condition.
 855                 if (retval < 0) {
 856                         if (errno == EBADF) {
 857                                 syslog(LOG_ERR, "sysdep: select() failed: %m");
 858                                 HuntBadSession();
 859                                 goto do_select;
 860                         }
 861                         if (errno != EINTR) {
 862                                 syslog(LOG_ERR, "sysdep: exiting: %m");
 863                                 server_shutting_down = 1;
 864                                 continue;
 865                         } else {
 866                                 if (server_shutting_down) {
 867                                         --num_workers;
 868                                         return(NULL);
 869                                 }
 870                                 goto do_select;
 871                         }
 872                 }
 873                 else if (retval == 0) {
 874                         if (server_shutting_down) {
 875                                 --num_workers;
 876                                 return(NULL);
 877                         }
 878                 }
 879
 880                 // Next, check to see if it's a new client connecting on a master socket.
 881
 882                 else if ((retval > 0) && (!server_shutting_down)) for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next) {
 883
 884                         if (FD_ISSET(serviceptr->msock, &readfds)) {
 885                                 ssock = accept(serviceptr->msock, NULL, 0);
 886                                 if (ssock >= 0) {
 887                                         syslog(LOG_DEBUG, "sysdep: new client socket %d", ssock);
 888
 889                                         // The master socket is non-blocking but the client
 890                                         // sockets need to be blocking, otherwise certain
 891                                         // operations barf on FreeBSD.  Not a fatal error.
 892                                         if (fcntl(ssock, F_SETFL, 0) < 0) {
 893                                                 syslog(LOG_ERR, "sysdep: Can't set socket to blocking: %m");
 894                                         }
 895
 896                                         // New context will be created already
 897                                         // set up in the CON_EXECUTING state.
 898                                         con = CreateNewContext();
 899
 900                                         // Assign our new socket number to it.
 901                                         con->tcp_port = serviceptr->tcp_port;
 902                                         con->client_socket = ssock;
 903                                         con->h_command_function = serviceptr->h_command_function;
 904                                         con->h_async_function = serviceptr->h_async_function;
 905                                         con->h_greeting_function = serviceptr->h_greeting_function;
 906                                         con->ServiceName = serviceptr->ServiceName;
 907
 908                                         // Connections on a local client are always from the same host
 909                                         if (serviceptr->sockpath != NULL) {
 910                                                 con->is_local_client = 1;
 911                                         }
 912
 913                                         // Set the SO_REUSEADDR socket option
 914                                         i = 1;
 915                                         setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 916                                         con->state = CON_GREETING;
 917                                         retval--;
 918                                         if (retval == 0)
 919                                                 break;
 920                                 }
 921                         }
 922                 }
 923
 924                 // It must be a client socket.  Find a context that has data
 925                 // waiting on its socket *and* is in the CON_IDLE state.  Any
 926                 // active sockets other than our chosen one are marked as
 927                 // CON_READY so the next thread that comes around can just bind
 928                 // to one without having to select() again.
 929                 begin_critical_section(S_SESSION_TABLE);
 930                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 931                         int checkfd = ptr->client_socket;
 932                         if ((checkfd != -1) && (ptr->state == CON_IDLE)){
 933                                 if (FD_ISSET(checkfd, &readfds)) {
 934                                         ptr->input_waiting = 1;
 935                                         if (!bind_me) {
 936                                                 bind_me = ptr;  // I choose you!
 937                                                 bind_me->state = CON_EXECUTING;
 938                                         }
 939                                         else {
 940                                                 ptr->state = CON_READY;
 941                                         }
 942                                 }
 943                                 else if ((ptr->is_async) && (ptr->async_waiting) && (ptr->h_async_function)) {
 944                                         if (!bind_me) {
 945                                                 bind_me = ptr;  // I choose you!
 946                                                 bind_me->state = CON_EXECUTING;
 947                                         }
 948                                         else {
 949                                                 ptr->state = CON_READY;
 950                                         }
 951                                 }
 952                         }
 953                 }
 954                 end_critical_section(S_SESSION_TABLE);
 955
 956 SKIP_SELECT:
 957                 // We're bound to a session
 958                 pthread_mutex_lock(&ThreadCountMutex);
 959                 ++active_workers;
 960                 pthread_mutex_unlock(&ThreadCountMutex);
 961
 962                 if (bind_me != NULL) {
 963                         become_session(bind_me);
 964
 965                         if (bind_me->state == CON_STARTING) {
 966                                 bind_me->state = CON_EXECUTING;
 967                                 begin_session(bind_me);
 968                                 bind_me->h_greeting_function();
 969                         }
 970                         // If the client has sent a command, execute it.
 971                         if (CC->input_waiting) {
 972                                 CC->h_command_function();
 973
 974                                 while (HaveMoreLinesWaiting(CC))
 975                                        CC->h_command_function();
 976
 977                                 CC->input_waiting = 0;
 978                         }
 979
 980                         // If there are asynchronous messages waiting and the client supports it, do those now
 981                         if ((CC->is_async) && (CC->async_waiting) && (CC->h_async_function != NULL)) {
 982                                 CC->h_async_function();
 983                                 CC->async_waiting = 0;
 984                         }
 985
 986                         force_purge = CC->kill_me;
 987                         become_session(NULL);
 988                         bind_me->state = CON_IDLE;
 989                 }
 990
 991                 dead_session_purge(force_purge);
 992                 do_housekeeping();
 993
 994                 pthread_mutex_lock(&ThreadCountMutex);
 995                 --active_workers;
 996                 if (    (active_workers + CtdlGetConfigInt("c_min_workers") < num_workers)
 997                         && (num_workers > CtdlGetConfigInt("c_min_workers"))
 998                 ) {
 999                         num_workers--;
1000                         pthread_mutex_unlock(&ThreadCountMutex);
1001                         return (NULL);
1002                 }
1003                 pthread_mutex_unlock(&ThreadCountMutex);
1004         }
1005
1006         // If control reaches this point, the server is shutting down
1007         pthread_mutex_lock(&ThreadCountMutex);
1008         --num_workers;
1009         pthread_mutex_unlock(&ThreadCountMutex);
1010         return(NULL);
1011 }
1012
1013
1014 // SyslogFacility()
1015 // Translate text facility name to syslog.h defined value.
1016 int SyslogFacility(char *name) {
1017         int i;
1018         struct {
1019                 int facility;
1020                 char *name;
1021         }   facTbl[] =
1022         {
1023                 {   LOG_KERN,   "kern"          },
1024                 {   LOG_USER,   "user"          },
1025                 {   LOG_MAIL,   "mail"          },
1026                 {   LOG_DAEMON, "daemon"        },
1027                 {   LOG_AUTH,   "auth"          },
1028                 {   LOG_SYSLOG, "syslog"        },
1029                 {   LOG_LPR,    "lpr"           },
1030                 {   LOG_NEWS,   "news"          },
1031                 {   LOG_UUCP,   "uucp"          },
1032                 {   LOG_LOCAL0, "local0"        },
1033                 {   LOG_LOCAL1, "local1"        },
1034                 {   LOG_LOCAL2, "local2"        },
1035                 {   LOG_LOCAL3, "local3"        },
1036                 {   LOG_LOCAL4, "local4"        },
1037                 {   LOG_LOCAL5, "local5"        },
1038                 {   LOG_LOCAL6, "local6"        },
1039                 {   LOG_LOCAL7, "local7"        },
1040                 {   0,            NULL          }
1041         };
1042         for(i = 0; facTbl[i].name != NULL; i++) {
1043                 if(!strcasecmp(name, facTbl[i].name))
1044                         return facTbl[i].facility;
1045         }
1046         return LOG_DAEMON;
1047 }