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) 1987-2023 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 #include "sysdep.h"
  12 #include <stdlib.h>
  13 #include <unistd.h>
  14 #include <sys/stat.h>
  15 #include <errno.h>
  16 #include <signal.h>
  17 #include <stdio.h>
  18 #include <syslog.h>
  19 #include <sys/syslog.h>
  20 #include <execinfo.h>
  21 #include <netdb.h>
  22 #include <sys/un.h>
  23 #include <sys/types.h>
  24 #include <sys/socket.h>
  25 #include <netinet/in.h>
  26 #include <arpa/inet.h>
  27 #include <netinet/tcp.h>
  28 #include <arpa/inet.h>
  29 #define SHOW_ME_VAPPEND_PRINTF
  30 #include <libcitadel.h>
  31 #include "citserver.h"
  32 #include "config.h"
  33 #include "ctdl_module.h"
  34 #include "sysdep_decls.h"
  35 #include "modules/crypto/serv_crypto.h" // Needed for init_ssl, client_write_ssl, client_read_ssl
  36 #include "housekeeping.h"
  37 #include "context.h"
  38
  39 // Signal handler to shut down the server.
  40 volatile int exit_signal = 0;
  41 volatile int shutdown_and_halt = 0;
  42 volatile int restart_server = 0;
  43 volatile int running_as_daemon = 0;
  44
  45
  46 static RETSIGTYPE signal_cleanup(int signum) {
  47         syslog(LOG_DEBUG, "sysdep: caught signal %d", signum);
  48         signal(SIGINT, SIG_DFL);
  49         signal(SIGHUP, SIG_DFL);
  50         signal(SIGTERM, SIG_DFL);
  51         signal(SIGSEGV, SIG_DFL);
  52         exit_signal = signum;
  53         server_shutting_down = 1;
  54         master_cleanup(signum);
  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                 exit(CTDLEXIT_THREAD);
  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                 exit(CTDLEXIT_THREAD);
  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         sigaddset(&set, SIGSEGV);
  94         sigprocmask(SIG_UNBLOCK, &set, NULL);
  95
  96         signal(SIGINT, signal_cleanup);
  97         signal(SIGHUP, signal_cleanup);
  98         signal(SIGTERM, signal_cleanup);
  99         signal(SIGSEGV, signal_cleanup);
 100
 101         // Do not shut down the server on broken pipe signals, otherwise the
 102         // whole Citadel service would come down whenever a single client
 103         // socket breaks.
 104         signal(SIGPIPE, SIG_IGN);
 105 }
 106
 107
 108 // This is a generic function to set up a master socket for listening on
 109 // a TCP port.  The server shuts down if the bind fails.  (IPv4/IPv6 version)
 110 //
 111 // ip_addr      IP address to bind
 112 // port_number  port number to bind
 113 // queue_len    number of incoming connections to allow in the queue
 114 int ctdl_tcp_server(char *ip_addr, int port_number, int queue_len) {
 115         struct protoent *p;
 116         struct sockaddr_in6 sin6;
 117         struct sockaddr_in sin4;
 118         int s, i, b;
 119         int ip_version = 6;
 120
 121         memset(&sin6, 0, sizeof(sin6));
 122         memset(&sin4, 0, sizeof(sin4));
 123         sin6.sin6_family = AF_INET6;
 124         sin4.sin_family = AF_INET;
 125
 126         if (    (ip_addr == NULL)                                                       // any IPv6
 127                 || (IsEmptyStr(ip_addr))
 128                 || (!strcmp(ip_addr, "*"))
 129         ) {
 130                 ip_version = 6;
 131                 sin6.sin6_addr = in6addr_any;
 132         }
 133         else if (!strcmp(ip_addr, "0.0.0.0")) {                                         // any IPv4
 134                 ip_version = 4;
 135                 sin4.sin_addr.s_addr = INADDR_ANY;
 136         }
 137         else if ((strchr(ip_addr, '.')) && (!strchr(ip_addr, ':'))) {                   // specific IPv4
 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                 ip_version = 6;
 146                 if (inet_pton(AF_INET6, ip_addr, &sin6.sin6_addr) <= 0) {
 147                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 148                         return (-1);
 149                 }
 150         }
 151
 152         if (port_number == 0) {
 153                 syslog(LOG_ALERT, "tcpserver: no port number was specified");
 154                 return (-1);
 155         }
 156         sin6.sin6_port = htons((u_short) port_number);
 157         sin4.sin_port = htons((u_short) port_number);
 158
 159         p = getprotobyname("tcp");
 160         if (p == NULL) {
 161                 syslog(LOG_ALERT, "tcpserver: getprotobyname: %m");
 162                 return (-1);
 163         }
 164
 165         s = socket( ((ip_version == 6) ? PF_INET6 : PF_INET), SOCK_STREAM, (p->p_proto));
 166         if (s < 0) {
 167                 syslog(LOG_ALERT, "tcpserver: socket: %m");
 168                 return (-1);
 169         }
 170         // Set some socket options that make sense.
 171         i = 1;
 172         setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 173
 174         if (ip_version == 6) {
 175                 b = bind(s, (struct sockaddr *) &sin6, sizeof(sin6));
 176         }
 177         else {
 178                 b = bind(s, (struct sockaddr *) &sin4, sizeof(sin4));
 179         }
 180
 181         if (b < 0) {
 182                 syslog(LOG_ALERT, "tcpserver: bind: %m");
 183                 return (-1);
 184         }
 185
 186         fcntl(s, F_SETFL, O_NONBLOCK);
 187
 188         if (listen(s, ((queue_len >= 5) ? queue_len : 5) ) < 0) {
 189                 syslog(LOG_ALERT, "tcpserver: listen: %m");
 190                 return (-1);
 191         }
 192         return (s);
 193 }
 194
 195
 196 // Create a Unix domain socket and listen on it
 197 int ctdl_uds_server(char *sockpath, int queue_len) {
 198         struct sockaddr_un addr;
 199         int s;
 200         int i;
 201         int actual_queue_len;
 202 #ifdef HAVE_STRUCT_UCRED
 203         int passcred = 1;
 204 #endif
 205
 206         actual_queue_len = queue_len;
 207         if (actual_queue_len < 5) actual_queue_len = 5;
 208
 209         i = unlink(sockpath);
 210         if ((i != 0) && (errno != ENOENT)) {
 211                 syslog(LOG_ERR, "udsserver: %m");
 212                 return(-1);
 213         }
 214
 215         memset(&addr, 0, sizeof(addr));
 216         addr.sun_family = AF_UNIX;
 217         safestrncpy(addr.sun_path, sockpath, sizeof addr.sun_path);
 218
 219         s = socket(AF_UNIX, SOCK_STREAM, 0);
 220         if (s < 0) {
 221                 syslog(LOG_ERR, "udsserver: socket: %m");
 222                 return(-1);
 223         }
 224
 225         if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 226                 syslog(LOG_ERR, "udsserver: bind: %m");
 227                 return(-1);
 228         }
 229
 230         // set to nonblock - we need this for some obscure situations
 231         if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) {
 232                 syslog(LOG_ERR, "udsserver: fcntl: %m");
 233                 close(s);
 234                 return(-1);
 235         }
 236
 237         if (listen(s, actual_queue_len) < 0) {
 238                 syslog(LOG_ERR, "udsserver: listen: %m");
 239                 return(-1);
 240         }
 241
 242 #ifdef HAVE_STRUCT_UCRED
 243         setsockopt(s, SOL_SOCKET, SO_PASSCRED, &passcred, sizeof(passcred));
 244 #endif
 245
 246         chmod(sockpath, S_ISGID|S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IWGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH);
 247         return(s);
 248 }
 249
 250
 251 // The following functions implement output buffering on operating systems which
 252 // support it (such as Linux and various BSD flavors).
 253 #ifndef HAVE_DARWIN
 254 #ifdef TCP_CORK
 255 #       define HAVE_TCP_BUFFERING
 256 #else
 257 #       ifdef TCP_NOPUSH
 258 #               define HAVE_TCP_BUFFERING
 259 #               define TCP_CORK TCP_NOPUSH
 260 #       endif
 261 #endif // TCP_CORK
 262 #endif // HAVE_DARWIN
 263
 264 static unsigned on = 1, off = 0;
 265
 266 void buffer_output(void) {
 267 #ifdef HAVE_TCP_BUFFERING
 268 #ifdef HAVE_OPENSSL
 269         if (!CC->redirect_ssl)
 270 #endif
 271                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 272 #endif
 273 }
 274
 275 void unbuffer_output(void) {
 276 #ifdef HAVE_TCP_BUFFERING
 277 #ifdef HAVE_OPENSSL
 278         if (!CC->redirect_ssl)
 279 #endif
 280                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 281 #endif
 282 }
 283
 284 void flush_output(void) {
 285 #ifdef HAVE_TCP_BUFFERING
 286         setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 287         setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 288 #endif
 289 }
 290
 291
 292 // close the client socket
 293 void client_close(void) {
 294         if (!CC) return;
 295         if (CC->client_socket <= 0) return;
 296         syslog(LOG_DEBUG, "sysdep: closing socket %d", CC->client_socket);
 297         close(CC->client_socket);
 298         CC->client_socket = -1 ;
 299 }
 300
 301
 302 // Send binary data to the client.
 303 int client_write(const char *buf, int nbytes) {
 304         int bytes_written = 0;
 305         int retval;
 306 #ifndef HAVE_TCP_BUFFERING
 307         int old_buffer_len = 0;
 308 #endif
 309         fd_set wset;
 310         CitContext *Ctx;
 311         int fdflags;
 312
 313         if (nbytes < 1) return(0);
 314
 315         Ctx = CC;
 316         if (Ctx->redirect_buffer != NULL) {
 317                 StrBufAppendBufPlain(Ctx->redirect_buffer, buf, nbytes, 0);
 318                 return 0;
 319         }
 320
 321 #ifdef HAVE_OPENSSL
 322         if (Ctx->redirect_ssl) {
 323                 client_write_ssl(buf, nbytes);
 324                 return 0;
 325         }
 326 #endif
 327         if (Ctx->client_socket == -1) return -1;
 328
 329         fdflags = fcntl(Ctx->client_socket, F_GETFL);
 330
 331         while ((bytes_written < nbytes) && (Ctx->client_socket != -1)){
 332                 if ((fdflags & O_NONBLOCK) == O_NONBLOCK) {
 333                         FD_ZERO(&wset);
 334                         FD_SET(Ctx->client_socket, &wset);
 335                         if (select(1, NULL, &wset, NULL, NULL) == -1) {
 336                                 if (errno == EINTR) {
 337                                         syslog(LOG_DEBUG, "sysdep: client_write(%d bytes) select() interrupted.", nbytes-bytes_written);
 338                                         if (server_shutting_down) {
 339                                                 CC->kill_me = KILLME_SELECT_INTERRUPTED;
 340                                                 return (-1);
 341                                         }
 342                                         else {
 343                                                 // can't trust fd's and stuff so we need to re-create them
 344                                                 continue;
 345                                         }
 346                                 }
 347                                 else {
 348                                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) select failed: %m", nbytes - bytes_written);
 349                                         client_close();
 350                                         Ctx->kill_me = KILLME_SELECT_FAILED;
 351                                         return -1;
 352                                 }
 353                         }
 354                 }
 355
 356                 retval = write(Ctx->client_socket, &buf[bytes_written], nbytes - bytes_written);
 357                 if (retval < 1) {
 358                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) failed: %m", nbytes - bytes_written);
 359                         client_close();
 360                         Ctx->kill_me = KILLME_WRITE_FAILED;
 361                         return -1;
 362                 }
 363                 bytes_written = bytes_written + retval;
 364         }
 365         return 0;
 366 }
 367
 368
 369 void cputbuf(const StrBuf *Buf) {
 370         client_write(ChrPtr(Buf), StrLength(Buf));
 371 }
 372
 373
 374 // Send formatted printable data to the client.
 375 // Implemented in terms of client_write() so it's technically not sysdep...
 376 void cprintf(const char *format, ...) {
 377         va_list arg_ptr;
 378         char buf[1024];
 379         int rc;
 380
 381         va_start(arg_ptr, format);
 382         rc = vsnprintf(buf, sizeof buf, format, arg_ptr);
 383         if (rc < 0) {
 384                 syslog(LOG_ERR,"Console output error occured. Format: %s",format);
 385         } else {
 386                 if (rc >= sizeof buf) {
 387                         // Output was truncated.
 388                         // Chop at the end of the buffer
 389                         buf[sizeof buf - 2] = '\n';
 390                         buf[sizeof buf - 1] = 0;
 391                 }
 392                 client_write(buf, strlen(buf));
 393         }
 394         va_end(arg_ptr);
 395 }
 396
 397
 398 // Read data from the client socket.
 399 //
 400 // sock         socket fd to read from
 401 // buf          buffer to read into
 402 // bytes        number of bytes to read
 403 // timeout      Number of seconds to wait before timing out
 404 //
 405 // Possible return values:
 406 //      1       Requested number of bytes has been read.
 407 //      0       Request timed out.
 408 //      -1      Connection is broken, or other error.
 409 int client_read_blob(StrBuf *Target, int bytes, int timeout) {
 410         const char *Error;
 411         int retval = 0;
 412
 413 #ifdef HAVE_OPENSSL
 414         if (CC->redirect_ssl) {
 415                 retval = client_read_sslblob(Target, bytes, timeout);
 416                 if (retval < 0) {
 417                         syslog(LOG_ERR, "sysdep: client_read_blob() failed");
 418                 }
 419         }
 420         else
 421 #endif
 422         {
 423                 retval = StrBufReadBLOBBuffered(Target,
 424                                                 CC->RecvBuf.Buf,
 425                                                 &CC->RecvBuf.ReadWritePointer,
 426                                                 &CC->client_socket,
 427                                                 1,
 428                                                 bytes,
 429                                                 O_TERM,
 430                                                 &Error
 431                 );
 432                 if (retval < 0) {
 433                         syslog(LOG_ERR, "sysdep: client_read_blob() failed: %s", Error);
 434                         client_close();
 435                         return retval;
 436                 }
 437         }
 438         return retval;
 439 }
 440
 441
 442 // to make client_read_random_blob() more efficient, increase buffer size.
 443 // just use in greeting function, else your buffer may be flushed
 444 void client_set_inbound_buf(long N) {
 445         FlushStrBuf(CC->RecvBuf.Buf);
 446         ReAdjustEmptyBuf(CC->RecvBuf.Buf, N * SIZ, N * SIZ);
 447 }
 448
 449
 450 int client_read_random_blob(StrBuf *Target, int timeout) {
 451         int rc;
 452
 453         rc =  client_read_blob(Target, 1, timeout);
 454         if (rc > 0) {
 455                 long len;
 456                 const char *pch;
 457
 458                 len = StrLength(CC->RecvBuf.Buf);
 459                 pch = ChrPtr(CC->RecvBuf.Buf);
 460
 461                 if (len > 0) {
 462                         if (CC->RecvBuf.ReadWritePointer != NULL) {
 463                                 len -= CC->RecvBuf.ReadWritePointer - pch;
 464                                 pch = CC->RecvBuf.ReadWritePointer;
 465                         }
 466                         StrBufAppendBufPlain(Target, pch, len, 0);
 467                         FlushStrBuf(CC->RecvBuf.Buf);
 468                         CC->RecvBuf.ReadWritePointer = NULL;
 469                         return StrLength(Target);
 470                 }
 471                 return rc;
 472         }
 473         else
 474                 return rc;
 475 }
 476
 477
 478 int client_read_to(char *buf, int bytes, int timeout) {
 479         int rc;
 480
 481         rc = client_read_blob(CC->MigrateBuf, bytes, timeout);
 482         if (rc < 0) {
 483                 *buf = '\0';
 484                 return rc;
 485         }
 486         else {
 487                 memcpy(buf,
 488                        ChrPtr(CC->MigrateBuf),
 489                        StrLength(CC->MigrateBuf) + 1);
 490                 FlushStrBuf(CC->MigrateBuf);
 491                 return rc;
 492         }
 493 }
 494
 495
 496 int HaveMoreLinesWaiting(CitContext *ctx) {
 497         if (    (ctx->kill_me != 0)
 498                 || ( (ctx->RecvBuf.ReadWritePointer == NULL)
 499                 && (StrLength(ctx->RecvBuf.Buf) == 0)
 500                 && (ctx->client_socket != -1))
 501         )
 502                 return 0;
 503         else
 504                 return 1;
 505 }
 506
 507
 508 // Read data from the client socket with default timeout.
 509 // (This is implemented in terms of client_read_to() and could be
 510 // justifiably moved out of sysdep.c)
 511 INLINE int client_read(char *buf, int bytes) {
 512         return(client_read_to(buf, bytes, CtdlGetConfigInt("c_sleeping")));
 513 }
 514
 515
 516 int CtdlClientGetLine(StrBuf *Target) {
 517         const char *Error;
 518         int rc;
 519
 520         FlushStrBuf(Target);
 521 #ifdef HAVE_OPENSSL
 522         if (CC->redirect_ssl) {
 523                 rc = client_readline_sslbuffer(Target, CC->RecvBuf.Buf, &CC->RecvBuf.ReadWritePointer, 1);
 524                 return rc;
 525         }
 526         else
 527 #endif
 528         {
 529                 rc = StrBufTCP_read_buffered_line_fast(Target,
 530                                                        CC->RecvBuf.Buf,
 531                                                        &CC->RecvBuf.ReadWritePointer,
 532                                                        &CC->client_socket,
 533                                                        5,
 534                                                        1,
 535                                                        &Error
 536                 );
 537                 return rc;
 538         }
 539 }
 540
 541
 542 // Get a LF-terminated line of text from the client.
 543 // (This is implemented in terms of client_read() and could be
 544 // justifiably moved out of sysdep.c)
 545 int client_getln(char *buf, int bufsize) {
 546         int i, retval;
 547         const char *pCh;
 548
 549         retval = CtdlClientGetLine(CC->MigrateBuf);
 550         if (retval < 0)
 551           return(retval >= 0);
 552
 553
 554         i = StrLength(CC->MigrateBuf);
 555         pCh = ChrPtr(CC->MigrateBuf);
 556         // Strip the trailing LF, and the trailing CR if present.
 557         if (bufsize <= i)
 558                 i = bufsize - 1;
 559         while ( (i > 0)
 560                 && ( (pCh[i - 1]==13)
 561                      || ( pCh[i - 1]==10)) ) {
 562                 i--;
 563         }
 564         memcpy(buf, pCh, i);
 565         buf[i] = 0;
 566
 567         FlushStrBuf(CC->MigrateBuf);
 568         if (retval < 0) {
 569                 safestrncpy(&buf[i], "000", bufsize - i);
 570         }
 571         return(retval >= 0);
 572 }
 573
 574
 575 // The system-dependent part of master_cleanup() - close the master socket.
 576 void sysdep_master_cleanup(void) {
 577         context_cleanup();
 578 }
 579
 580
 581
 582 pid_t current_child;
 583 void supervisor_process_shutdown(int signum) {
 584         kill(current_child, signum);
 585         unlink(file_pid_file);
 586         exit(0);
 587 }
 588
 589 int nFireUps = 0;
 590 int nFireUpsNonRestart = 0;
 591 pid_t ForkedPid = 1;
 592
 593 // Start running as a daemon.
 594 void start_daemon(int unused) {
 595         int status = 0;
 596         pid_t child = 0;
 597         FILE *fp;
 598         int do_restart = 0;
 599         current_child = 0;
 600
 601         // Close stdin/stdout/stderr and replace them with /dev/null.
 602         // We don't just call close() because we don't want these fd's
 603         // to be reused for other files.
 604         child = fork();
 605         if (child != 0) {
 606                 exit(0);
 607         }
 608
 609         signal(SIGHUP, SIG_IGN);
 610         signal(SIGINT, SIG_IGN);
 611         signal(SIGQUIT, SIG_IGN);
 612
 613         setsid();
 614         umask(0);
 615         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
 616                 (freopen("/dev/null", "w", stdout) != stdout) ||
 617                 (freopen("/dev/null", "w", stderr) != stderr)
 618         ) {
 619                 syslog(LOG_ERR, "sysdep: unable to reopen stdio: %m");
 620         }
 621
 622         do {
 623                 current_child = fork();
 624                 signal(SIGTERM, supervisor_process_shutdown);
 625                 if (current_child < 0) {
 626                         perror("fork");
 627                         exit(errno);
 628                 }
 629                 else if (current_child == 0) {
 630                         return; // continue starting citadel.
 631                 }
 632                 else {
 633                         fp = fopen(file_pid_file, "w");
 634                         if (fp != NULL) {
 635                                 fprintf(fp, ""F_PID_T"\n", getpid());
 636                                 fclose(fp);
 637                         }
 638                         waitpid(current_child, &status, 0);
 639                 }
 640                 nFireUpsNonRestart = nFireUps;
 641
 642                 // Exit code 0 means the watcher should exit
 643                 if (WIFEXITED(status) && (WEXITSTATUS(status) == CTDLEXIT_SHUTDOWN)) {
 644                         do_restart = 0;
 645                 }
 646
 647                 // Exit code 101-109 means the watcher should exit
 648                 else if (WIFEXITED(status) && (WEXITSTATUS(status) >= 101) && (WEXITSTATUS(status) <= 109)) {
 649                         do_restart = 0;
 650                 }
 651
 652                 // Any other exit code, or no exit code, means we should restart.
 653                 else {
 654                         do_restart = 1;
 655                         nFireUps++;
 656                         ForkedPid = current_child;
 657                 }
 658
 659         } while (do_restart);
 660
 661         unlink(file_pid_file);
 662         exit(WEXITSTATUS(status));
 663 }
 664
 665
 666 void checkcrash(void) {
 667         if (nFireUpsNonRestart != nFireUps) {
 668                 StrBuf *CrashMail;
 669                 CrashMail = NewStrBuf();
 670                 syslog(LOG_ALERT, "sysdep: posting crash message");
 671                 StrBufPrintf(CrashMail,
 672                         " \n"
 673                         " The Citadel server process (citserver) terminated unexpectedly."
 674                         "\n \n"
 675                         " This could be the result of a bug in the server program, or some external "
 676                         "factor.\n \n"
 677                         " You can obtain more information about this by enabling core dumps.\n \n"
 678                         " For more information, please see:\n \n"
 679                         " http://citadel.org/doku.php?id=faq:mastering_your_os:gdb#how.do.i.make.my.system.produce.core-files"
 680                         "\n \n"
 681
 682                         " If you have already done this, the core dump is likely to be found at %score.%d\n"
 683                         ,
 684                         ctdl_run_dir, ForkedPid);
 685                 CtdlAideMessage(ChrPtr(CrashMail), "Citadel server process terminated unexpectedly");
 686                 FreeStrBuf(&CrashMail);
 687         }
 688 }
 689
 690
 691 // Generic routine to convert a login name to a full name (gecos)
 692 // Returns nonzero if a conversion took place
 693 int convert_login(char NameToConvert[]) {
 694         struct passwd *pw;
 695         unsigned int a;
 696
 697         pw = getpwnam(NameToConvert);
 698         if (pw == NULL) {
 699                 return(0);
 700         }
 701         else {
 702                 strcpy(NameToConvert, pw->pw_gecos);
 703                 for (a=0; a<strlen(NameToConvert); ++a) {
 704                         if (NameToConvert[a] == ',') NameToConvert[a] = 0;
 705                 }
 706                 return(1);
 707         }
 708 }
 709
 710
 711 void HuntBadSession(void) {
 712         int highest;
 713         CitContext *ptr;
 714         fd_set readfds;
 715         struct timeval tv;
 716         struct ServiceFunctionHook *serviceptr;
 717
 718         // Next, add all of the client sockets
 719         begin_critical_section(S_SESSION_TABLE);
 720         for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 721                 if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 722                         continue;
 723                 // Initialize the fdset.
 724                 FD_ZERO(&readfds);
 725                 highest = 0;
 726                 tv.tv_sec = 0;          // wake up every second if no input
 727                 tv.tv_usec = 0;
 728
 729                 // Don't select on dead sessions, only truly idle ones
 730                 if (    (ptr->state == CON_IDLE)
 731                         && (ptr->kill_me == 0)
 732                         && (ptr->client_socket > 0)
 733                 ) {
 734                         FD_SET(ptr->client_socket, &readfds);
 735                         if (ptr->client_socket > highest)
 736                                 highest = ptr->client_socket;
 737
 738                         if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) && (errno == EBADF)) {
 739                                 // Gotcha!
 740                                 syslog(LOG_ERR,
 741                                        "sysdep: killing session CC[%d] bad FD: [%d] User[%s] Host[%s:%s]",
 742                                         ptr->cs_pid,
 743                                         ptr->client_socket,
 744                                         ptr->curr_user,
 745                                         ptr->cs_host,
 746                                         ptr->cs_addr
 747                                 );
 748                                 ptr->kill_me = 1;
 749                                 ptr->client_socket = -1;
 750                                 break;
 751                         }
 752                 }
 753         }
 754         end_critical_section(S_SESSION_TABLE);
 755
 756         // First, add the various master sockets to the fdset.
 757         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 758
 759                 // Initialize the fdset.
 760                 highest = 0;
 761                 tv.tv_sec = 0;          // wake up every second if no input
 762                 tv.tv_usec = 0;
 763
 764                 FD_SET(serviceptr->msock, &readfds);
 765                 if (serviceptr->msock > highest) {
 766                         highest = serviceptr->msock;
 767                 }
 768                 if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) && (errno == EBADF)) {
 769                         // Gotcha! server socket dead? commit suicide!
 770                         syslog(LOG_ERR, "sysdep: found bad FD: %d and its a server socket! Shutting Down!", serviceptr->msock);
 771                         server_shutting_down = 1;
 772                         break;
 773                 }
 774         }
 775 }
 776
 777
 778 // Main server loop
 779 // select() can wake up on any of the following conditions:
 780 // 1. A new client connection on a master socket
 781 // 2. Received data on a client socket
 782 // 3. A timer event
 783 // That's why we are blocking on select() and not accept().
 784 void *worker_thread(void *blah) {
 785         int highest;
 786         CitContext *ptr;
 787         CitContext *bind_me = NULL;
 788         fd_set readfds;
 789         int retval = 0;
 790         struct timeval tv;
 791         int force_purge = 0;
 792         struct ServiceFunctionHook *serviceptr;
 793         int ssock;                      // Descriptor for client socket
 794         CitContext *con = NULL;         // Temporary context pointer
 795         int i;
 796
 797         pthread_mutex_lock(&ThreadCountMutex);
 798         ++num_workers;
 799         pthread_mutex_unlock(&ThreadCountMutex);
 800
 801         while (!server_shutting_down) {
 802
 803                 // make doubly sure we're not holding any stale db handles which might cause a deadlock
 804                 cdb_check_handles();
 805 do_select:      force_purge = 0;
 806                 bind_me = NULL;         // Which session shall we handle?
 807
 808                 // Initialize the fdset
 809                 FD_ZERO(&readfds);
 810                 highest = 0;
 811
 812                 // First, add the various master sockets to the fdset.
 813                 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 814                         FD_SET(serviceptr->msock, &readfds);
 815                         if (serviceptr->msock > highest) {
 816                                 highest = serviceptr->msock;
 817                         }
 818                 }
 819
 820                 // Next, add all of the client sockets.
 821                 begin_critical_section(S_SESSION_TABLE);
 822                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 823                         if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 824                             continue;
 825
 826                         // Don't select on dead sessions, only truly idle ones
 827                         if (    (ptr->state == CON_IDLE)
 828                                 && (ptr->kill_me == 0)
 829                                 && (ptr->client_socket > 0)
 830                         ) {
 831                                 FD_SET(ptr->client_socket, &readfds);
 832                                 if (ptr->client_socket > highest)
 833                                         highest = ptr->client_socket;
 834                         }
 835                         if ((bind_me == NULL) && (ptr->state == CON_READY)) {
 836                                 bind_me = ptr;
 837                                 ptr->state = CON_EXECUTING;
 838                                 break;
 839                         }
 840                         if ((bind_me == NULL) && (ptr->state == CON_GREETING)) {
 841                                 bind_me = ptr;
 842                                 ptr->state = CON_STARTING;
 843                                 break;
 844                         }
 845                 }
 846                 end_critical_section(S_SESSION_TABLE);
 847
 848                 if (bind_me) {
 849                         goto SKIP_SELECT;
 850                 }
 851
 852                 // If we got this far, it means that there are no sessions
 853                 // which a previous thread marked for attention, so we go
 854                 // ahead and get ready to select().
 855
 856                 if (!server_shutting_down) {
 857                         tv.tv_sec = 1;          // wake up every second if no input
 858                         tv.tv_usec = 0;
 859                         retval = select(highest + 1, &readfds, NULL, NULL, &tv);
 860                 }
 861                 else {
 862                         --num_workers;
 863                         return NULL;
 864                 }
 865
 866                 // Now figure out who made this select() unblock.
 867                 // First, check for an error or exit condition.
 868                 if (retval < 0) {
 869                         if (errno == EBADF) {
 870                                 syslog(LOG_ERR, "sysdep: select() failed: %m");
 871                                 HuntBadSession();
 872                                 goto do_select;
 873                         }
 874                         if (errno != EINTR) {
 875                                 syslog(LOG_ERR, "sysdep: exiting: %m");
 876                                 server_shutting_down = 1;
 877                                 continue;
 878                         } else {
 879                                 if (server_shutting_down) {
 880                                         --num_workers;
 881                                         return(NULL);
 882                                 }
 883                                 goto do_select;
 884                         }
 885                 }
 886                 else if (retval == 0) {
 887                         if (server_shutting_down) {
 888                                 --num_workers;
 889                                 return(NULL);
 890                         }
 891                 }
 892
 893                 // Next, check to see if it's a new client connecting on a master socket.
 894
 895                 else if ((retval > 0) && (!server_shutting_down)) for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next) {
 896
 897                         if (FD_ISSET(serviceptr->msock, &readfds)) {
 898                                 ssock = accept(serviceptr->msock, NULL, 0);
 899                                 if (ssock >= 0) {
 900                                         syslog(LOG_DEBUG, "sysdep: new client socket %d", ssock);
 901
 902                                         // The master socket is non-blocking but the client
 903                                         // sockets need to be blocking, otherwise certain
 904                                         // operations barf on FreeBSD.  Not a fatal error.
 905                                         if (fcntl(ssock, F_SETFL, 0) < 0) {
 906                                                 syslog(LOG_ERR, "sysdep: Can't set socket to blocking: %m");
 907                                         }
 908
 909                                         // New context will be created already
 910                                         // set up in the CON_EXECUTING state.
 911                                         con = CreateNewContext();
 912
 913                                         // Assign our new socket number to it.
 914                                         con->tcp_port = serviceptr->tcp_port;
 915                                         con->client_socket = ssock;
 916                                         con->h_command_function = serviceptr->h_command_function;
 917                                         con->h_async_function = serviceptr->h_async_function;
 918                                         con->h_greeting_function = serviceptr->h_greeting_function;
 919                                         con->ServiceName = serviceptr->ServiceName;
 920
 921                                         // Connections on a local client are always from the same host
 922                                         if (serviceptr->sockpath != NULL) {
 923                                                 con->is_local_client = 1;
 924                                         }
 925
 926                                         // Set the SO_REUSEADDR socket option
 927                                         i = 1;
 928                                         setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 929                                         con->state = CON_GREETING;
 930                                         retval--;
 931                                         if (retval == 0)
 932                                                 break;
 933                                 }
 934                         }
 935                 }
 936
 937                 // It must be a client socket.  Find a context that has data
 938                 // waiting on its socket *and* is in the CON_IDLE state.  Any
 939                 // active sockets other than our chosen one are marked as
 940                 // CON_READY so the next thread that comes around can just bind
 941                 // to one without having to select() again.
 942                 begin_critical_section(S_SESSION_TABLE);
 943                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 944                         int checkfd = ptr->client_socket;
 945                         if ((checkfd != -1) && (ptr->state == CON_IDLE) ){
 946                                 if (FD_ISSET(checkfd, &readfds)) {
 947                                         ptr->input_waiting = 1;
 948                                         if (!bind_me) {
 949                                                 bind_me = ptr;  // I choose you!
 950                                                 bind_me->state = CON_EXECUTING;
 951                                         }
 952                                         else {
 953                                                 ptr->state = CON_READY;
 954                                         }
 955                                 } else if ((ptr->is_async) && (ptr->async_waiting) && (ptr->h_async_function)) {
 956                                         if (!bind_me) {
 957                                                 bind_me = ptr;  // I choose you!
 958                                                 bind_me->state = CON_EXECUTING;
 959                                         }
 960                                         else {
 961                                                 ptr->state = CON_READY;
 962                                         }
 963                                 }
 964                         }
 965                 }
 966                 end_critical_section(S_SESSION_TABLE);
 967
 968 SKIP_SELECT:
 969                 // We're bound to a session
 970                 pthread_mutex_lock(&ThreadCountMutex);
 971                 ++active_workers;
 972                 pthread_mutex_unlock(&ThreadCountMutex);
 973
 974                 if (bind_me != NULL) {
 975                         become_session(bind_me);
 976
 977                         if (bind_me->state == CON_STARTING) {
 978                                 bind_me->state = CON_EXECUTING;
 979                                 begin_session(bind_me);
 980                                 bind_me->h_greeting_function();
 981                         }
 982                         // If the client has sent a command, execute it.
 983                         if (CC->input_waiting) {
 984                                 CC->h_command_function();
 985
 986                                 while (HaveMoreLinesWaiting(CC))
 987                                        CC->h_command_function();
 988
 989                                 CC->input_waiting = 0;
 990                         }
 991
 992                         // If there are asynchronous messages waiting and the client supports it, do those now
 993                         if ((CC->is_async) && (CC->async_waiting) && (CC->h_async_function != NULL)) {
 994                                 CC->h_async_function();
 995                                 CC->async_waiting = 0;
 996                         }
 997
 998                         force_purge = CC->kill_me;
 999                         become_session(NULL);
1000                         bind_me->state = CON_IDLE;
1001                 }
1002
1003                 dead_session_purge(force_purge);
1004                 do_housekeeping();
1005
1006                 pthread_mutex_lock(&ThreadCountMutex);
1007                 --active_workers;
1008                 if ((active_workers + CtdlGetConfigInt("c_min_workers") < num_workers) &&
1009                     (num_workers > CtdlGetConfigInt("c_min_workers")))
1010                 {
1011                         num_workers--;
1012                         pthread_mutex_unlock(&ThreadCountMutex);
1013                         return (NULL);
1014                 }
1015                 pthread_mutex_unlock(&ThreadCountMutex);
1016         }
1017
1018         // If control reaches this point, the server is shutting down
1019         pthread_mutex_lock(&ThreadCountMutex);
1020         --num_workers;
1021         pthread_mutex_unlock(&ThreadCountMutex);
1022         return(NULL);
1023 }
1024
1025
1026 // SyslogFacility()
1027 // Translate text facility name to syslog.h defined value.
1028 int SyslogFacility(char *name)
1029 {
1030         int i;
1031         struct
1032         {
1033                 int facility;
1034                 char *name;
1035         }   facTbl[] =
1036         {
1037                 {   LOG_KERN,   "kern"          },
1038                 {   LOG_USER,   "user"          },
1039                 {   LOG_MAIL,   "mail"          },
1040                 {   LOG_DAEMON, "daemon"        },
1041                 {   LOG_AUTH,   "auth"          },
1042                 {   LOG_SYSLOG, "syslog"        },
1043                 {   LOG_LPR,    "lpr"           },
1044                 {   LOG_NEWS,   "news"          },
1045                 {   LOG_UUCP,   "uucp"          },
1046                 {   LOG_LOCAL0, "local0"        },
1047                 {   LOG_LOCAL1, "local1"        },
1048                 {   LOG_LOCAL2, "local2"        },
1049                 {   LOG_LOCAL3, "local3"        },
1050                 {   LOG_LOCAL4, "local4"        },
1051                 {   LOG_LOCAL5, "local5"        },
1052                 {   LOG_LOCAL6, "local6"        },
1053                 {   LOG_LOCAL7, "local7"        },
1054                 {   0,            NULL          }
1055         };
1056         for(i = 0; facTbl[i].name != NULL; i++) {
1057                 if(!strcasecmp(name, facTbl[i].name))
1058                         return facTbl[i].facility;
1059         }
1060         return LOG_DAEMON;
1061 }