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) 1987-2022 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                 ip_version = 4;
 133                 sin4.sin_addr.s_addr = INADDR_ANY;
 134         }
 135         else if ((strchr(ip_addr, '.')) && (!strchr(ip_addr, ':'))) {                   // specific IPv4
 136                 ip_version = 4;
 137                 if (inet_pton(AF_INET, ip_addr, &sin4.sin_addr) <= 0) {
 138                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 139                         return (-1);
 140                 }
 141         }
 142         else {                                                                          // specific IPv6
 143                 ip_version = 6;
 144                 if (inet_pton(AF_INET6, ip_addr, &sin6.sin6_addr) <= 0) {
 145                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 146                         return (-1);
 147                 }
 148         }
 149
 150         if (port_number == 0) {
 151                 syslog(LOG_ALERT, "tcpserver: no port number was specified");
 152                 return (-1);
 153         }
 154         sin6.sin6_port = htons((u_short) port_number);
 155         sin4.sin_port = htons((u_short) port_number);
 156
 157         p = getprotobyname("tcp");
 158         if (p == NULL) {
 159                 syslog(LOG_ALERT, "tcpserver: getprotobyname: %m");
 160                 return (-1);
 161         }
 162
 163         s = socket( ((ip_version == 6) ? PF_INET6 : PF_INET), SOCK_STREAM, (p->p_proto));
 164         if (s < 0) {
 165                 syslog(LOG_ALERT, "tcpserver: socket: %m");
 166                 return (-1);
 167         }
 168         // Set some socket options that make sense.
 169         i = 1;
 170         setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 171
 172         if (ip_version == 6) {
 173                 b = bind(s, (struct sockaddr *) &sin6, sizeof(sin6));
 174         }
 175         else {
 176                 b = bind(s, (struct sockaddr *) &sin4, sizeof(sin4));
 177         }
 178
 179         if (b < 0) {
 180                 syslog(LOG_ALERT, "tcpserver: bind: %m");
 181                 return (-1);
 182         }
 183
 184         fcntl(s, F_SETFL, O_NONBLOCK);
 185
 186         if (listen(s, ((queue_len >= 5) ? queue_len : 5) ) < 0) {
 187                 syslog(LOG_ALERT, "tcpserver: listen: %m");
 188                 return (-1);
 189         }
 190         return (s);
 191 }
 192
 193
 194 // Create a Unix domain socket and listen on it
 195 int ctdl_uds_server(char *sockpath, int queue_len) {
 196         struct sockaddr_un addr;
 197         int s;
 198         int i;
 199         int actual_queue_len;
 200 #ifdef HAVE_STRUCT_UCRED
 201         int passcred = 1;
 202 #endif
 203
 204         actual_queue_len = queue_len;
 205         if (actual_queue_len < 5) actual_queue_len = 5;
 206
 207         i = unlink(sockpath);
 208         if ((i != 0) && (errno != ENOENT)) {
 209                 syslog(LOG_ERR, "udsserver: %m");
 210                 return(-1);
 211         }
 212
 213         memset(&addr, 0, sizeof(addr));
 214         addr.sun_family = AF_UNIX;
 215         safestrncpy(addr.sun_path, sockpath, sizeof addr.sun_path);
 216
 217         s = socket(AF_UNIX, SOCK_STREAM, 0);
 218         if (s < 0) {
 219                 syslog(LOG_ERR, "udsserver: socket: %m");
 220                 return(-1);
 221         }
 222
 223         if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 224                 syslog(LOG_ERR, "udsserver: bind: %m");
 225                 return(-1);
 226         }
 227
 228         // set to nonblock - we need this for some obscure situations
 229         if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) {
 230                 syslog(LOG_ERR, "udsserver: fcntl: %m");
 231                 close(s);
 232                 return(-1);
 233         }
 234
 235         if (listen(s, actual_queue_len) < 0) {
 236                 syslog(LOG_ERR, "udsserver: listen: %m");
 237                 return(-1);
 238         }
 239
 240 #ifdef HAVE_STRUCT_UCRED
 241         setsockopt(s, SOL_SOCKET, SO_PASSCRED, &passcred, sizeof(passcred));
 242 #endif
 243
 244         chmod(sockpath, S_ISGID|S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IWGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH);
 245         return(s);
 246 }
 247
 248
 249 // The following functions implement output buffering on operating systems which
 250 // support it (such as Linux and various BSD flavors).
 251 #ifndef HAVE_DARWIN
 252 #ifdef TCP_CORK
 253 #       define HAVE_TCP_BUFFERING
 254 #else
 255 #       ifdef TCP_NOPUSH
 256 #               define HAVE_TCP_BUFFERING
 257 #               define TCP_CORK TCP_NOPUSH
 258 #       endif
 259 #endif // TCP_CORK
 260 #endif // HAVE_DARWIN
 261
 262 static unsigned on = 1, off = 0;
 263
 264 void buffer_output(void) {
 265 #ifdef HAVE_TCP_BUFFERING
 266 #ifdef HAVE_OPENSSL
 267         if (!CC->redirect_ssl)
 268 #endif
 269                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 270 #endif
 271 }
 272
 273 void unbuffer_output(void) {
 274 #ifdef HAVE_TCP_BUFFERING
 275 #ifdef HAVE_OPENSSL
 276         if (!CC->redirect_ssl)
 277 #endif
 278                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 279 #endif
 280 }
 281
 282 void flush_output(void) {
 283 #ifdef HAVE_TCP_BUFFERING
 284         setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 285         setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 286 #endif
 287 }
 288
 289
 290 // close the client socket
 291 void client_close(void) {
 292         if (!CC) return;
 293         if (CC->client_socket <= 0) return;
 294         syslog(LOG_DEBUG, "sysdep: closing socket %d", CC->client_socket);
 295         close(CC->client_socket);
 296         CC->client_socket = -1 ;
 297 }
 298
 299
 300 // Send binary data to the client.
 301 int client_write(const char *buf, int nbytes) {
 302         int bytes_written = 0;
 303         int retval;
 304 #ifndef HAVE_TCP_BUFFERING
 305         int old_buffer_len = 0;
 306 #endif
 307         fd_set wset;
 308         CitContext *Ctx;
 309         int fdflags;
 310
 311         if (nbytes < 1) return(0);
 312
 313         Ctx = CC;
 314         if (Ctx->redirect_buffer != NULL) {
 315                 StrBufAppendBufPlain(Ctx->redirect_buffer, buf, nbytes, 0);
 316                 return 0;
 317         }
 318
 319 #ifdef HAVE_OPENSSL
 320         if (Ctx->redirect_ssl) {
 321                 client_write_ssl(buf, nbytes);
 322                 return 0;
 323         }
 324 #endif
 325         if (Ctx->client_socket == -1) return -1;
 326
 327         fdflags = fcntl(Ctx->client_socket, F_GETFL);
 328
 329         while ((bytes_written < nbytes) && (Ctx->client_socket != -1)){
 330                 if ((fdflags & O_NONBLOCK) == O_NONBLOCK) {
 331                         FD_ZERO(&wset);
 332                         FD_SET(Ctx->client_socket, &wset);
 333                         if (select(1, NULL, &wset, NULL, NULL) == -1) {
 334                                 if (errno == EINTR) {
 335                                         syslog(LOG_DEBUG, "sysdep: client_write(%d bytes) select() interrupted.", nbytes-bytes_written);
 336                                         if (server_shutting_down) {
 337                                                 CC->kill_me = KILLME_SELECT_INTERRUPTED;
 338                                                 return (-1);
 339                                         }
 340                                         else {
 341                                                 // can't trust fd's and stuff so we need to re-create them
 342                                                 continue;
 343                                         }
 344                                 }
 345                                 else {
 346                                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) select failed: %m", nbytes - bytes_written);
 347                                         client_close();
 348                                         Ctx->kill_me = KILLME_SELECT_FAILED;
 349                                         return -1;
 350                                 }
 351                         }
 352                 }
 353
 354                 retval = write(Ctx->client_socket, &buf[bytes_written], nbytes - bytes_written);
 355                 if (retval < 1) {
 356                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) failed: %m", nbytes - bytes_written);
 357                         client_close();
 358                         Ctx->kill_me = KILLME_WRITE_FAILED;
 359                         return -1;
 360                 }
 361                 bytes_written = bytes_written + retval;
 362         }
 363         return 0;
 364 }
 365
 366
 367 void cputbuf(const StrBuf *Buf) {
 368         client_write(ChrPtr(Buf), StrLength(Buf));
 369 }
 370
 371
 372 // Send formatted printable data to the client.
 373 // Implemented in terms of client_write() so it's technically not sysdep...
 374 void cprintf(const char *format, ...) {
 375         va_list arg_ptr;
 376         char buf[1024];
 377
 378         va_start(arg_ptr, format);
 379         if (vsnprintf(buf, sizeof buf, format, arg_ptr) == -1)
 380                 buf[sizeof buf - 2] = '\n';
 381         client_write(buf, strlen(buf));
 382         va_end(arg_ptr);
 383 }
 384
 385
 386 // Read data from the client socket.
 387 //
 388 // sock         socket fd to read from
 389 // buf          buffer to read into
 390 // bytes        number of bytes to read
 391 // timeout      Number of seconds to wait before timing out
 392 //
 393 // Possible return values:
 394 //      1       Requested number of bytes has been read.
 395 //      0       Request timed out.
 396 //      -1      Connection is broken, or other error.
 397 int client_read_blob(StrBuf *Target, int bytes, int timeout) {
 398         const char *Error;
 399         int retval = 0;
 400
 401 #ifdef HAVE_OPENSSL
 402         if (CC->redirect_ssl) {
 403                 retval = client_read_sslblob(Target, bytes, timeout);
 404                 if (retval < 0) {
 405                         syslog(LOG_ERR, "sysdep: client_read_blob() failed");
 406                 }
 407         }
 408         else
 409 #endif
 410         {
 411                 retval = StrBufReadBLOBBuffered(Target,
 412                                                 CC->RecvBuf.Buf,
 413                                                 &CC->RecvBuf.ReadWritePointer,
 414                                                 &CC->client_socket,
 415                                                 1,
 416                                                 bytes,
 417                                                 O_TERM,
 418                                                 &Error
 419                 );
 420                 if (retval < 0) {
 421                         syslog(LOG_ERR, "sysdep: client_read_blob() failed: %s", Error);
 422                         client_close();
 423                         return retval;
 424                 }
 425         }
 426         return retval;
 427 }
 428
 429
 430 // to make client_read_random_blob() more efficient, increase buffer size.
 431 // just use in greeting function, else your buffer may be flushed
 432 void client_set_inbound_buf(long N) {
 433         FlushStrBuf(CC->RecvBuf.Buf);
 434         ReAdjustEmptyBuf(CC->RecvBuf.Buf, N * SIZ, N * SIZ);
 435 }
 436
 437
 438 int client_read_random_blob(StrBuf *Target, int timeout) {
 439         int rc;
 440
 441         rc =  client_read_blob(Target, 1, timeout);
 442         if (rc > 0) {
 443                 long len;
 444                 const char *pch;
 445
 446                 len = StrLength(CC->RecvBuf.Buf);
 447                 pch = ChrPtr(CC->RecvBuf.Buf);
 448
 449                 if (len > 0) {
 450                         if (CC->RecvBuf.ReadWritePointer != NULL) {
 451                                 len -= CC->RecvBuf.ReadWritePointer - pch;
 452                                 pch = CC->RecvBuf.ReadWritePointer;
 453                         }
 454                         StrBufAppendBufPlain(Target, pch, len, 0);
 455                         FlushStrBuf(CC->RecvBuf.Buf);
 456                         CC->RecvBuf.ReadWritePointer = NULL;
 457                         return StrLength(Target);
 458                 }
 459                 return rc;
 460         }
 461         else
 462                 return rc;
 463 }
 464
 465
 466 int client_read_to(char *buf, int bytes, int timeout) {
 467         int rc;
 468
 469         rc = client_read_blob(CC->MigrateBuf, bytes, timeout);
 470         if (rc < 0) {
 471                 *buf = '\0';
 472                 return rc;
 473         }
 474         else {
 475                 memcpy(buf,
 476                        ChrPtr(CC->MigrateBuf),
 477                        StrLength(CC->MigrateBuf) + 1);
 478                 FlushStrBuf(CC->MigrateBuf);
 479                 return rc;
 480         }
 481 }
 482
 483
 484 int HaveMoreLinesWaiting(CitContext *ctx) {
 485         if (    (ctx->kill_me != 0)
 486                 || ( (ctx->RecvBuf.ReadWritePointer == NULL)
 487                 && (StrLength(ctx->RecvBuf.Buf) == 0)
 488                 && (ctx->client_socket != -1))
 489         )
 490                 return 0;
 491         else
 492                 return 1;
 493 }
 494
 495
 496 // Read data from the client socket with default timeout.
 497 // (This is implemented in terms of client_read_to() and could be
 498 // justifiably moved out of sysdep.c)
 499 INLINE int client_read(char *buf, int bytes) {
 500         return(client_read_to(buf, bytes, CtdlGetConfigInt("c_sleeping")));
 501 }
 502
 503
 504 int CtdlClientGetLine(StrBuf *Target) {
 505         const char *Error;
 506         int rc;
 507
 508         FlushStrBuf(Target);
 509 #ifdef HAVE_OPENSSL
 510         if (CC->redirect_ssl) {
 511                 rc = client_readline_sslbuffer(Target, CC->RecvBuf.Buf, &CC->RecvBuf.ReadWritePointer, 1);
 512                 return rc;
 513         }
 514         else
 515 #endif
 516         {
 517                 rc = StrBufTCP_read_buffered_line_fast(Target,
 518                                                        CC->RecvBuf.Buf,
 519                                                        &CC->RecvBuf.ReadWritePointer,
 520                                                        &CC->client_socket,
 521                                                        5,
 522                                                        1,
 523                                                        &Error
 524                 );
 525                 return rc;
 526         }
 527 }
 528
 529
 530 // Get a LF-terminated line of text from the client.
 531 // (This is implemented in terms of client_read() and could be
 532 // justifiably moved out of sysdep.c)
 533 int client_getln(char *buf, int bufsize) {
 534         int i, retval;
 535         const char *pCh;
 536
 537         retval = CtdlClientGetLine(CC->MigrateBuf);
 538         if (retval < 0)
 539           return(retval >= 0);
 540
 541
 542         i = StrLength(CC->MigrateBuf);
 543         pCh = ChrPtr(CC->MigrateBuf);
 544         // Strip the trailing LF, and the trailing CR if present.
 545         if (bufsize <= i)
 546                 i = bufsize - 1;
 547         while ( (i > 0)
 548                 && ( (pCh[i - 1]==13)
 549                      || ( pCh[i - 1]==10)) ) {
 550                 i--;
 551         }
 552         memcpy(buf, pCh, i);
 553         buf[i] = 0;
 554
 555         FlushStrBuf(CC->MigrateBuf);
 556         if (retval < 0) {
 557                 safestrncpy(&buf[i], "000", bufsize - i);
 558         }
 559         return(retval >= 0);
 560 }
 561
 562
 563 // Cleanup any contexts that are left lying around
 564 void close_masters(void) {
 565         struct ServiceFunctionHook *serviceptr;
 566         const char *Text;
 567
 568         // close all protocol master sockets
 569         for (serviceptr = ServiceHookTable; serviceptr != NULL;
 570             serviceptr = serviceptr->next ) {
 571
 572                 if (serviceptr->tcp_port > 0) {
 573                         if (serviceptr->msock == -1) {
 574                                 Text = "not closing again";
 575                         }
 576                         else {
 577                                 Text = "Closing";
 578                         }
 579                         syslog(LOG_INFO, "sysdep: %s %d listener on port %d",
 580                                Text,
 581                                serviceptr->msock,
 582                                serviceptr->tcp_port
 583                         );
 584                         serviceptr->tcp_port = 0;
 585                 }
 586
 587                 if (serviceptr->sockpath != NULL) {
 588                         if (serviceptr->msock == -1) {
 589                                 Text = "not closing again";
 590                         }
 591                         else {
 592                                 Text = "Closing";
 593                         }
 594                         syslog(LOG_INFO, "sysdep: %s %d listener on '%s'",
 595                                Text,
 596                                serviceptr->msock,
 597                                serviceptr->sockpath
 598                         );
 599                 }
 600
 601                 if (serviceptr->msock != -1) {
 602                         close(serviceptr->msock);
 603                         serviceptr->msock = -1;
 604                 }
 605
 606                 // If it's a Unix domain socket, remove the file.
 607                 if (serviceptr->sockpath != NULL) {
 608                         unlink(serviceptr->sockpath);
 609                         serviceptr->sockpath = NULL;
 610                 }
 611         }
 612 }
 613
 614
 615 // The system-dependent part of master_cleanup() - close the master socket.
 616 void sysdep_master_cleanup(void) {
 617         close_masters();
 618         context_cleanup();
 619 }
 620
 621
 622
 623 pid_t current_child;
 624 void graceful_shutdown(int signum) {
 625         kill(current_child, signum);
 626         unlink(file_pid_file);
 627         exit(0);
 628 }
 629
 630 int nFireUps = 0;
 631 int nFireUpsNonRestart = 0;
 632 pid_t ForkedPid = 1;
 633
 634 // Start running as a daemon.
 635 void start_daemon(int unused) {
 636         int status = 0;
 637         pid_t child = 0;
 638         FILE *fp;
 639         int do_restart = 0;
 640         current_child = 0;
 641
 642         // Close stdin/stdout/stderr and replace them with /dev/null.
 643         // We don't just call close() because we don't want these fd's
 644         // to be reused for other files.
 645         child = fork();
 646         if (child != 0) {
 647                 exit(0);
 648         }
 649
 650         signal(SIGHUP, SIG_IGN);
 651         signal(SIGINT, SIG_IGN);
 652         signal(SIGQUIT, SIG_IGN);
 653
 654         setsid();
 655         umask(0);
 656         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
 657                 (freopen("/dev/null", "w", stdout) != stdout) ||
 658                 (freopen("/dev/null", "w", stderr) != stderr)
 659         ) {
 660                 syslog(LOG_ERR, "sysdep: unable to reopen stdio: %m");
 661         }
 662
 663         do {
 664                 current_child = fork();
 665                 signal(SIGTERM, graceful_shutdown);
 666                 if (current_child < 0) {
 667                         perror("fork");
 668                         exit(errno);
 669                 }
 670                 else if (current_child == 0) {
 671                         return; // continue starting citadel.
 672                 }
 673                 else {
 674                         fp = fopen(file_pid_file, "w");
 675                         if (fp != NULL) {
 676                                 fprintf(fp, ""F_PID_T"\n", getpid());
 677                                 fclose(fp);
 678                         }
 679                         waitpid(current_child, &status, 0);
 680                 }
 681                 nFireUpsNonRestart = nFireUps;
 682
 683                 // Exit code 0 means the watcher should exit
 684                 if (WIFEXITED(status) && (WEXITSTATUS(status) == CTDLEXIT_SHUTDOWN)) {
 685                         do_restart = 0;
 686                 }
 687
 688                 // Exit code 101-109 means the watcher should exit
 689                 else if (WIFEXITED(status) && (WEXITSTATUS(status) >= 101) && (WEXITSTATUS(status) <= 109)) {
 690                         do_restart = 0;
 691                 }
 692
 693                 // Any other exit code, or no exit code, means we should restart.
 694                 else {
 695                         do_restart = 1;
 696                         nFireUps++;
 697                         ForkedPid = current_child;
 698                 }
 699
 700         } while (do_restart);
 701
 702         unlink(file_pid_file);
 703         exit(WEXITSTATUS(status));
 704 }
 705
 706
 707 void checkcrash(void) {
 708         if (nFireUpsNonRestart != nFireUps) {
 709                 StrBuf *CrashMail;
 710                 CrashMail = NewStrBuf();
 711                 syslog(LOG_ALERT, "sysdep: posting crash message");
 712                 StrBufPrintf(CrashMail,
 713                         " \n"
 714                         " The Citadel server process (citserver) terminated unexpectedly."
 715                         "\n \n"
 716                         " This could be the result of a bug in the server program, or some external "
 717                         "factor.\n \n"
 718                         " You can obtain more information about this by enabling core dumps.\n \n"
 719                         " For more information, please see:\n \n"
 720                         " http://citadel.org/doku.php?id=faq:mastering_your_os:gdb#how.do.i.make.my.system.produce.core-files"
 721                         "\n \n"
 722
 723                         " If you have already done this, the core dump is likely to be found at %score.%d\n"
 724                         ,
 725                         ctdl_run_dir, ForkedPid);
 726                 CtdlAideMessage(ChrPtr(CrashMail), "Citadel server process terminated unexpectedly");
 727                 FreeStrBuf(&CrashMail);
 728         }
 729 }
 730
 731
 732 // Generic routine to convert a login name to a full name (gecos)
 733 // Returns nonzero if a conversion took place
 734 int convert_login(char NameToConvert[]) {
 735         struct passwd *pw;
 736         unsigned int a;
 737
 738         pw = getpwnam(NameToConvert);
 739         if (pw == NULL) {
 740                 return(0);
 741         }
 742         else {
 743                 strcpy(NameToConvert, pw->pw_gecos);
 744                 for (a=0; a<strlen(NameToConvert); ++a) {
 745                         if (NameToConvert[a] == ',') NameToConvert[a] = 0;
 746                 }
 747                 return(1);
 748         }
 749 }
 750
 751
 752 void HuntBadSession(void) {
 753         int highest;
 754         CitContext *ptr;
 755         fd_set readfds;
 756         struct timeval tv;
 757         struct ServiceFunctionHook *serviceptr;
 758
 759         // Next, add all of the client sockets
 760         begin_critical_section(S_SESSION_TABLE);
 761         for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 762                 if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 763                         continue;
 764                 // Initialize the fdset.
 765                 FD_ZERO(&readfds);
 766                 highest = 0;
 767                 tv.tv_sec = 0;          // wake up every second if no input
 768                 tv.tv_usec = 0;
 769
 770                 // Don't select on dead sessions, only truly idle ones
 771                 if (    (ptr->state == CON_IDLE)
 772                         && (ptr->kill_me == 0)
 773                         && (ptr->client_socket > 0)
 774                 ) {
 775                         FD_SET(ptr->client_socket, &readfds);
 776                         if (ptr->client_socket > highest)
 777                                 highest = ptr->client_socket;
 778
 779                         if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) && (errno == EBADF)) {
 780                                 // Gotcha!
 781                                 syslog(LOG_ERR,
 782                                        "sysdep: killing session CC[%d] bad FD: [%d] User[%s] Host[%s:%s]",
 783                                         ptr->cs_pid,
 784                                         ptr->client_socket,
 785                                         ptr->curr_user,
 786                                         ptr->cs_host,
 787                                         ptr->cs_addr
 788                                 );
 789                                 ptr->kill_me = 1;
 790                                 ptr->client_socket = -1;
 791                                 break;
 792                         }
 793                 }
 794         }
 795         end_critical_section(S_SESSION_TABLE);
 796
 797         // First, add the various master sockets to the fdset.
 798         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 799
 800                 // Initialize the fdset.
 801                 highest = 0;
 802                 tv.tv_sec = 0;          // wake up every second if no input
 803                 tv.tv_usec = 0;
 804
 805                 FD_SET(serviceptr->msock, &readfds);
 806                 if (serviceptr->msock > highest) {
 807                         highest = serviceptr->msock;
 808                 }
 809                 if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) && (errno == EBADF)) {
 810                         // Gotcha! server socket dead? commit suicide!
 811                         syslog(LOG_ERR, "sysdep: found bad FD: %d and its a server socket! Shutting Down!", serviceptr->msock);
 812                         server_shutting_down = 1;
 813                         break;
 814                 }
 815         }
 816 }
 817
 818
 819 // This loop just keeps going and going and going...
 820 //
 821 // TECHNICAL NOTE -- AJC 2022-JUN-20
 822 // This loop was designed in the 20th Century when accept() was susceptible to the "thundering herd" problem.
 823 // Today we can simplify it by having all worker threads block on accept() and the OS will do the right thing when a
 824 // connection arrives and only unblock one thread.   This will require a separate execution path for non-client activity
 825 // such as housekeeping but maybe we can move those to a "supervisor thread".
 826 //
 827 // This implementation works and is not broken in any way, but if we can simplify it we should.
 828 //
 829 void *worker_thread(void *blah) {
 830         int highest;
 831         CitContext *ptr;
 832         CitContext *bind_me = NULL;
 833         fd_set readfds;
 834         int retval = 0;
 835         struct timeval tv;
 836         int force_purge = 0;
 837         struct ServiceFunctionHook *serviceptr;
 838         int ssock;                      // Descriptor for client socket
 839         CitContext *con = NULL;         // Temporary context pointer
 840         int i;
 841
 842         pthread_mutex_lock(&ThreadCountMutex);
 843         ++num_workers;
 844         pthread_mutex_unlock(&ThreadCountMutex);
 845
 846         while (!server_shutting_down) {
 847
 848                 // make doubly sure we're not holding any stale db handles which might cause a deadlock
 849                 cdb_check_handles();
 850 do_select:      force_purge = 0;
 851                 bind_me = NULL;         // Which session shall we handle?
 852
 853                 // Initialize the fdset
 854                 FD_ZERO(&readfds);
 855                 highest = 0;
 856
 857                 // First, add the various master sockets to the fdset.
 858                 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 859                         FD_SET(serviceptr->msock, &readfds);
 860                         if (serviceptr->msock > highest) {
 861                                 highest = serviceptr->msock;
 862                         }
 863                 }
 864
 865                 // Next, add all of the client sockets.
 866                 begin_critical_section(S_SESSION_TABLE);
 867                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 868                         if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 869                             continue;
 870
 871                         // Don't select on dead sessions, only truly idle ones
 872                         if (    (ptr->state == CON_IDLE)
 873                                 && (ptr->kill_me == 0)
 874                                 && (ptr->client_socket > 0)
 875                         ) {
 876                                 FD_SET(ptr->client_socket, &readfds);
 877                                 if (ptr->client_socket > highest)
 878                                         highest = ptr->client_socket;
 879                         }
 880                         if ((bind_me == NULL) && (ptr->state == CON_READY)) {
 881                                 bind_me = ptr;
 882                                 ptr->state = CON_EXECUTING;
 883                                 break;
 884                         }
 885                         if ((bind_me == NULL) && (ptr->state == CON_GREETING)) {
 886                                 bind_me = ptr;
 887                                 ptr->state = CON_STARTING;
 888                                 break;
 889                         }
 890                 }
 891                 end_critical_section(S_SESSION_TABLE);
 892
 893                 if (bind_me) {
 894                         goto SKIP_SELECT;
 895                 }
 896
 897                 // If we got this far, it means that there are no sessions
 898                 // which a previous thread marked for attention, so we go
 899                 // ahead and get ready to select().
 900
 901                 if (!server_shutting_down) {
 902                         tv.tv_sec = 1;          // wake up every second if no input
 903                         tv.tv_usec = 0;
 904                         retval = select(highest + 1, &readfds, NULL, NULL, &tv);
 905                 }
 906                 else {
 907                         --num_workers;
 908                         return NULL;
 909                 }
 910
 911                 // Now figure out who made this select() unblock.
 912                 // First, check for an error or exit condition.
 913                 if (retval < 0) {
 914                         if (errno == EBADF) {
 915                                 syslog(LOG_ERR, "sysdep: select() failed: %m");
 916                                 HuntBadSession();
 917                                 goto do_select;
 918                         }
 919                         if (errno != EINTR) {
 920                                 syslog(LOG_ERR, "sysdep: exiting: %m");
 921                                 server_shutting_down = 1;
 922                                 continue;
 923                         } else {
 924                                 if (server_shutting_down) {
 925                                         --num_workers;
 926                                         return(NULL);
 927                                 }
 928                                 goto do_select;
 929                         }
 930                 }
 931                 else if (retval == 0) {
 932                         if (server_shutting_down) {
 933                                 --num_workers;
 934                                 return(NULL);
 935                         }
 936                 }
 937
 938                 // Next, check to see if it's a new client connecting on a master socket.
 939
 940                 else if ((retval > 0) && (!server_shutting_down)) for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next) {
 941
 942                         if (FD_ISSET(serviceptr->msock, &readfds)) {
 943                                 ssock = accept(serviceptr->msock, NULL, 0);
 944                                 if (ssock >= 0) {
 945                                         syslog(LOG_DEBUG, "sysdep: new client socket %d", ssock);
 946
 947                                         // The master socket is non-blocking but the client
 948                                         // sockets need to be blocking, otherwise certain
 949                                         // operations barf on FreeBSD.  Not a fatal error.
 950                                         if (fcntl(ssock, F_SETFL, 0) < 0) {
 951                                                 syslog(LOG_ERR, "sysdep: Can't set socket to blocking: %m");
 952                                         }
 953
 954                                         // New context will be created already
 955                                         // set up in the CON_EXECUTING state.
 956                                         con = CreateNewContext();
 957
 958                                         // Assign our new socket number to it.
 959                                         con->tcp_port = serviceptr->tcp_port;
 960                                         con->client_socket = ssock;
 961                                         con->h_command_function = serviceptr->h_command_function;
 962                                         con->h_async_function = serviceptr->h_async_function;
 963                                         con->h_greeting_function = serviceptr->h_greeting_function;
 964                                         con->ServiceName = serviceptr->ServiceName;
 965
 966                                         // Connections on a local client are always from the same host
 967                                         if (serviceptr->sockpath != NULL) {
 968                                                 con->is_local_client = 1;
 969                                         }
 970
 971                                         // Set the SO_REUSEADDR socket option
 972                                         i = 1;
 973                                         setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 974                                         con->state = CON_GREETING;
 975                                         retval--;
 976                                         if (retval == 0)
 977                                                 break;
 978                                 }
 979                         }
 980                 }
 981
 982                 // It must be a client socket.  Find a context that has data
 983                 // waiting on its socket *and* is in the CON_IDLE state.  Any
 984                 // active sockets other than our chosen one are marked as
 985                 // CON_READY so the next thread that comes around can just bind
 986                 // to one without having to select() again.
 987                 begin_critical_section(S_SESSION_TABLE);
 988                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 989                         int checkfd = ptr->client_socket;
 990                         if ((checkfd != -1) && (ptr->state == CON_IDLE) ){
 991                                 if (FD_ISSET(checkfd, &readfds)) {
 992                                         ptr->input_waiting = 1;
 993                                         if (!bind_me) {
 994                                                 bind_me = ptr;  // I choose you!
 995                                                 bind_me->state = CON_EXECUTING;
 996                                         }
 997                                         else {
 998                                                 ptr->state = CON_READY;
 999                                         }
1000                                 } else if ((ptr->is_async) && (ptr->async_waiting) && (ptr->h_async_function)) {
1001                                         if (!bind_me) {
1002                                                 bind_me = ptr;  // I choose you!
1003                                                 bind_me->state = CON_EXECUTING;
1004                                         }
1005                                         else {
1006                                                 ptr->state = CON_READY;
1007                                         }
1008                                 }
1009                         }
1010                 }
1011                 end_critical_section(S_SESSION_TABLE);
1012
1013 SKIP_SELECT:
1014                 // We're bound to a session
1015                 pthread_mutex_lock(&ThreadCountMutex);
1016                 ++active_workers;
1017                 pthread_mutex_unlock(&ThreadCountMutex);
1018
1019                 if (bind_me != NULL) {
1020                         become_session(bind_me);
1021
1022                         if (bind_me->state == CON_STARTING) {
1023                                 bind_me->state = CON_EXECUTING;
1024                                 begin_session(bind_me);
1025                                 bind_me->h_greeting_function();
1026                         }
1027                         // If the client has sent a command, execute it.
1028                         if (CC->input_waiting) {
1029                                 CC->h_command_function();
1030
1031                                 while (HaveMoreLinesWaiting(CC))
1032                                        CC->h_command_function();
1033
1034                                 CC->input_waiting = 0;
1035                         }
1036
1037                         // If there are asynchronous messages waiting and the client supports it, do those now
1038                         if ((CC->is_async) && (CC->async_waiting) && (CC->h_async_function != NULL)) {
1039                                 CC->h_async_function();
1040                                 CC->async_waiting = 0;
1041                         }
1042
1043                         force_purge = CC->kill_me;
1044                         become_session(NULL);
1045                         bind_me->state = CON_IDLE;
1046                 }
1047
1048                 dead_session_purge(force_purge);
1049                 do_housekeeping();
1050
1051                 pthread_mutex_lock(&ThreadCountMutex);
1052                 --active_workers;
1053                 if ((active_workers + CtdlGetConfigInt("c_min_workers") < num_workers) &&
1054                     (num_workers > CtdlGetConfigInt("c_min_workers")))
1055                 {
1056                         num_workers--;
1057                         pthread_mutex_unlock(&ThreadCountMutex);
1058                         return (NULL);
1059                 }
1060                 pthread_mutex_unlock(&ThreadCountMutex);
1061         }
1062
1063         // If control reaches this point, the server is shutting down
1064         pthread_mutex_lock(&ThreadCountMutex);
1065         --num_workers;
1066         pthread_mutex_unlock(&ThreadCountMutex);
1067         return(NULL);
1068 }
1069
1070
1071 // SyslogFacility()
1072 // Translate text facility name to syslog.h defined value.
1073 int SyslogFacility(char *name)
1074 {
1075         int i;
1076         struct
1077         {
1078                 int facility;
1079                 char *name;
1080         }   facTbl[] =
1081         {
1082                 {   LOG_KERN,   "kern"          },
1083                 {   LOG_USER,   "user"          },
1084                 {   LOG_MAIL,   "mail"          },
1085                 {   LOG_DAEMON, "daemon"        },
1086                 {   LOG_AUTH,   "auth"          },
1087                 {   LOG_SYSLOG, "syslog"        },
1088                 {   LOG_LPR,    "lpr"           },
1089                 {   LOG_NEWS,   "news"          },
1090                 {   LOG_UUCP,   "uucp"          },
1091                 {   LOG_LOCAL0, "local0"        },
1092                 {   LOG_LOCAL1, "local1"        },
1093                 {   LOG_LOCAL2, "local2"        },
1094                 {   LOG_LOCAL3, "local3"        },
1095                 {   LOG_LOCAL4, "local4"        },
1096                 {   LOG_LOCAL5, "local5"        },
1097                 {   LOG_LOCAL6, "local6"        },
1098                 {   LOG_LOCAL7, "local7"        },
1099                 {   0,            NULL          }
1100         };
1101         for(i = 0; facTbl[i].name != NULL; i++) {
1102                 if(!strcasecmp(name, facTbl[i].name))
1103                         return facTbl[i].facility;
1104         }
1105         return LOG_DAEMON;
1106 }