citadel/sysdep.c

   1 // Citadel "system dependent" stuff.
   2 //
   3 // Here's where we (hopefully) have most parts of the Citadel server that
   4 // might need tweaking when run on different operating system variants.
   5 //
   6 // Copyright (c) 1987-2021 by the citadel.org team
   7 //
   8 // This program is open source software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License, version 3.
  10 //
  11 // This program is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 #include "sysdep.h"
  17 #include <stdlib.h>
  18 #include <unistd.h>
  19 #include <sys/stat.h>
  20 #include <errno.h>
  21 #include <signal.h>
  22 #include <stdio.h>
  23 #include <syslog.h>
  24 #include <sys/syslog.h>
  25 #include <execinfo.h>
  26 #include <netdb.h>
  27 #include <sys/un.h>
  28 #include <sys/types.h>
  29 #include <sys/socket.h>
  30 #include <netinet/in.h>
  31 #include <arpa/inet.h>
  32 #include <netinet/tcp.h>
  33 #include <arpa/inet.h>
  34 #define SHOW_ME_VAPPEND_PRINTF
  35 #include <libcitadel.h>
  36 #include "citserver.h"
  37 #include "config.h"
  38 #include "ctdl_module.h"
  39 #include "sysdep_decls.h"
  40 #include "modules/crypto/serv_crypto.h" // Needed for init_ssl, client_write_ssl, client_read_ssl, destruct_ssl
  41 #include "housekeeping.h"
  42 #include "context.h"
  43
  44 // Signal handler to shut down the server.
  45 volatile int exit_signal = 0;
  46 volatile int shutdown_and_halt = 0;
  47 volatile int restart_server = 0;
  48 volatile int running_as_daemon = 0;
  49
  50
  51 static RETSIGTYPE signal_cleanup(int signum) {
  52         syslog(LOG_DEBUG, "sysdep: caught signal %d - backtrace follows:", signum);
  53
  54         void *bt[1024];
  55         int bt_size;
  56         char **bt_syms;
  57         int i;
  58         FILE *backtrace_fp = NULL;
  59
  60         if (backtrace_filename != NULL) {
  61                 backtrace_fp = fopen(backtrace_filename, "w");
  62         }
  63
  64         bt_size = backtrace(bt, 1024);
  65         bt_syms = backtrace_symbols(bt, bt_size);
  66         for (i = 1; i < bt_size; i++) {
  67                 syslog(LOG_DEBUG, "%s", bt_syms[i]);
  68                 if (backtrace_fp) {
  69                         fprintf(backtrace_fp, "%s\n", bt_syms[i]);
  70                 }
  71         }
  72         free(bt_syms);
  73
  74         if (backtrace_fp) {
  75                 fclose(backtrace_fp);
  76         }
  77
  78         exit_signal = signum;
  79         server_shutting_down = 1;
  80 }
  81
  82
  83 // Some initialization stuff...
  84 void init_sysdep(void) {
  85         sigset_t set;
  86
  87         // Avoid vulnerabilities related to FD_SETSIZE if we can.
  88 #ifdef FD_SETSIZE
  89 #ifdef RLIMIT_NOFILE
  90         struct rlimit rl;
  91         getrlimit(RLIMIT_NOFILE, &rl);
  92         rl.rlim_cur = FD_SETSIZE;
  93         rl.rlim_max = FD_SETSIZE;
  94         setrlimit(RLIMIT_NOFILE, &rl);
  95 #endif
  96 #endif
  97
  98         // If we've got OpenSSL, we're going to use it.
  99 #ifdef HAVE_OPENSSL
 100         init_ssl();
 101 #endif
 102
 103         if (pthread_key_create(&ThreadKey, NULL) != 0) {                        // TSD for threads
 104                 syslog(LOG_ERR, "pthread_key_create() : %m");
 105                 abort();
 106         }
 107
 108         if (pthread_key_create(&MyConKey, NULL) != 0) {                         // TSD for sessions
 109                 syslog(LOG_CRIT, "sysdep: can't create TSD key: %m");
 110                 abort();
 111         }
 112
 113         // Interript, hangup, and terminate signals should cause the server to shut down.
 114         sigemptyset(&set);
 115         sigaddset(&set, SIGINT);
 116         sigaddset(&set, SIGHUP);
 117         sigaddset(&set, SIGTERM);
 118         sigaddset(&set, SIGSEGV);
 119         sigprocmask(SIG_UNBLOCK, &set, NULL);
 120
 121         signal(SIGINT, signal_cleanup);
 122         signal(SIGHUP, signal_cleanup);
 123         signal(SIGTERM, signal_cleanup);
 124         signal(SIGSEGV, signal_cleanup);
 125
 126         // Do not shut down the server on broken pipe signals, otherwise the
 127         // whole Citadel service would come down whenever a single client
 128         // socket breaks.
 129         signal(SIGPIPE, SIG_IGN);
 130 }
 131
 132
 133 // This is a generic function to set up a master socket for listening on
 134 // a TCP port.  The server shuts down if the bind fails.  (IPv4/IPv6 version)
 135 //
 136 // ip_addr      IP address to bind
 137 // port_number  port number to bind
 138 // queue_len    number of incoming connections to allow in the queue
 139 int ctdl_tcp_server(char *ip_addr, int port_number, int queue_len) {
 140         struct protoent *p;
 141         struct sockaddr_in6 sin6;
 142         struct sockaddr_in sin4;
 143         int s, i, b;
 144         int ip_version = 6;
 145
 146         memset(&sin6, 0, sizeof(sin6));
 147         memset(&sin4, 0, sizeof(sin4));
 148         sin6.sin6_family = AF_INET6;
 149         sin4.sin_family = AF_INET;
 150
 151         if (    (ip_addr == NULL)                                                       // any IPv6
 152                 || (IsEmptyStr(ip_addr))
 153                 || (!strcmp(ip_addr, "*"))
 154         ) {
 155                 ip_version = 6;
 156                 sin6.sin6_addr = in6addr_any;
 157         }
 158         else if (!strcmp(ip_addr, "0.0.0.0"))                                           // any IPv4
 159         {
 160                 ip_version = 4;
 161                 sin4.sin_addr.s_addr = INADDR_ANY;
 162         }
 163         else if ((strchr(ip_addr, '.')) && (!strchr(ip_addr, ':')))                     // specific IPv4
 164         {
 165                 ip_version = 4;
 166                 if (inet_pton(AF_INET, ip_addr, &sin4.sin_addr) <= 0) {
 167                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 168                         return (-1);
 169                 }
 170         }
 171         else                                                                            // specific IPv6
 172         {
 173                 ip_version = 6;
 174                 if (inet_pton(AF_INET6, ip_addr, &sin6.sin6_addr) <= 0) {
 175                         syslog(LOG_ALERT, "tcpserver: inet_pton: %m");
 176                         return (-1);
 177                 }
 178         }
 179
 180         if (port_number == 0) {
 181                 syslog(LOG_ALERT, "tcpserver: no port number was specified");
 182                 return (-1);
 183         }
 184         sin6.sin6_port = htons((u_short) port_number);
 185         sin4.sin_port = htons((u_short) port_number);
 186
 187         p = getprotobyname("tcp");
 188         if (p == NULL) {
 189                 syslog(LOG_ALERT, "tcpserver: getprotobyname: %m");
 190                 return (-1);
 191         }
 192
 193         s = socket( ((ip_version == 6) ? PF_INET6 : PF_INET), SOCK_STREAM, (p->p_proto));
 194         if (s < 0) {
 195                 syslog(LOG_ALERT, "tcpserver: socket: %m");
 196                 return (-1);
 197         }
 198         // Set some socket options that make sense.
 199         i = 1;
 200         setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 201
 202         if (ip_version == 6) {
 203                 b = bind(s, (struct sockaddr *) &sin6, sizeof(sin6));
 204         }
 205         else {
 206                 b = bind(s, (struct sockaddr *) &sin4, sizeof(sin4));
 207         }
 208
 209         if (b < 0) {
 210                 syslog(LOG_ALERT, "tcpserver: bind: %m");
 211                 return (-1);
 212         }
 213
 214         fcntl(s, F_SETFL, O_NONBLOCK);
 215
 216         if (listen(s, ((queue_len >= 5) ? queue_len : 5) ) < 0) {
 217                 syslog(LOG_ALERT, "tcpserver: listen: %m");
 218                 return (-1);
 219         }
 220         return (s);
 221 }
 222
 223
 224 // Create a Unix domain socket and listen on it
 225 int ctdl_uds_server(char *sockpath, int queue_len) {
 226         struct sockaddr_un addr;
 227         int s;
 228         int i;
 229         int actual_queue_len;
 230 #ifdef HAVE_STRUCT_UCRED
 231         int passcred = 1;
 232 #endif
 233
 234         actual_queue_len = queue_len;
 235         if (actual_queue_len < 5) actual_queue_len = 5;
 236
 237         i = unlink(sockpath);
 238         if ((i != 0) && (errno != ENOENT)) {
 239                 syslog(LOG_ERR, "udsserver: %m");
 240                 return(-1);
 241         }
 242
 243         memset(&addr, 0, sizeof(addr));
 244         addr.sun_family = AF_UNIX;
 245         safestrncpy(addr.sun_path, sockpath, sizeof addr.sun_path);
 246
 247         s = socket(AF_UNIX, SOCK_STREAM, 0);
 248         if (s < 0) {
 249                 syslog(LOG_ERR, "udsserver: socket: %m");
 250                 return(-1);
 251         }
 252
 253         if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 254                 syslog(LOG_ERR, "udsserver: bind: %m");
 255                 return(-1);
 256         }
 257
 258         // set to nonblock - we need this for some obscure situations
 259         if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) {
 260                 syslog(LOG_ERR, "udsserver: fcntl: %m");
 261                 close(s);
 262                 return(-1);
 263         }
 264
 265         if (listen(s, actual_queue_len) < 0) {
 266                 syslog(LOG_ERR, "udsserver: listen: %m");
 267                 return(-1);
 268         }
 269
 270 #ifdef HAVE_STRUCT_UCRED
 271         setsockopt(s, SOL_SOCKET, SO_PASSCRED, &passcred, sizeof(passcred));
 272 #endif
 273
 274         chmod(sockpath, S_ISGID|S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IWGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH);
 275         return(s);
 276 }
 277
 278
 279 // The following functions implement output buffering on operating systems which
 280 // support it (such as Linux and various BSD flavors).
 281 #ifndef HAVE_DARWIN
 282 #ifdef TCP_CORK
 283 #       define HAVE_TCP_BUFFERING
 284 #else
 285 #       ifdef TCP_NOPUSH
 286 #               define HAVE_TCP_BUFFERING
 287 #               define TCP_CORK TCP_NOPUSH
 288 #       endif
 289 #endif // TCP_CORK
 290 #endif // HAVE_DARWIN
 291
 292 static unsigned on = 1, off = 0;
 293
 294 void buffer_output(void) {
 295 #ifdef HAVE_TCP_BUFFERING
 296 #ifdef HAVE_OPENSSL
 297         if (!CC->redirect_ssl)
 298 #endif
 299                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 300 #endif
 301 }
 302
 303 void unbuffer_output(void) {
 304 #ifdef HAVE_TCP_BUFFERING
 305 #ifdef HAVE_OPENSSL
 306         if (!CC->redirect_ssl)
 307 #endif
 308                 setsockopt(CC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 309 #endif
 310 }
 311
 312 void flush_output(void) {
 313 #ifdef HAVE_TCP_BUFFERING
 314         struct CitContext *CCC = CC;
 315         setsockopt(CCC->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
 316         setsockopt(CCC->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
 317 #endif
 318 }
 319
 320
 321 // close the client socket
 322 void client_close(void) {
 323         CitContext *CCC = CC;
 324
 325         if (!CCC) return;
 326         if (CCC->client_socket <= 0) return;
 327         syslog(LOG_DEBUG, "sysdep: closing socket %d", CCC->client_socket);
 328         close(CCC->client_socket);
 329         CCC->client_socket = -1 ;
 330 }
 331
 332
 333 // Send binary data to the client.
 334 int client_write(const char *buf, int nbytes)
 335 {
 336         int bytes_written = 0;
 337         int retval;
 338 #ifndef HAVE_TCP_BUFFERING
 339         int old_buffer_len = 0;
 340 #endif
 341         fd_set wset;
 342         CitContext *Ctx;
 343         int fdflags;
 344
 345         if (nbytes < 1) return(0);
 346
 347         Ctx = CC;
 348
 349         if (Ctx->redirect_buffer != NULL) {
 350                 StrBufAppendBufPlain(Ctx->redirect_buffer,
 351                                      buf, nbytes, 0);
 352                 return 0;
 353         }
 354
 355 #ifdef HAVE_OPENSSL
 356         if (Ctx->redirect_ssl) {
 357                 client_write_ssl(buf, nbytes);
 358                 return 0;
 359         }
 360 #endif
 361         if (Ctx->client_socket == -1) return -1;
 362
 363         fdflags = fcntl(Ctx->client_socket, F_GETFL);
 364
 365         while ((bytes_written < nbytes) && (Ctx->client_socket != -1)){
 366                 if ((fdflags & O_NONBLOCK) == O_NONBLOCK) {
 367                         FD_ZERO(&wset);
 368                         FD_SET(Ctx->client_socket, &wset);
 369                         if (select(1, NULL, &wset, NULL, NULL) == -1) {
 370                                 if (errno == EINTR)
 371                                 {
 372                                         syslog(LOG_DEBUG, "sysdep: client_write(%d bytes) select() interrupted.", nbytes-bytes_written);
 373                                         if (server_shutting_down) {
 374                                                 CC->kill_me = KILLME_SELECT_INTERRUPTED;
 375                                                 return (-1);
 376                                         } else {
 377                                                 // can't trust fd's and stuff so we need to re-create them
 378                                                 continue;
 379                                         }
 380                                 } else {
 381                                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) select failed: %m", nbytes - bytes_written);
 382                                         client_close();
 383                                         Ctx->kill_me = KILLME_SELECT_FAILED;
 384                                         return -1;
 385                                 }
 386                         }
 387                 }
 388
 389                 retval = write(Ctx->client_socket, &buf[bytes_written], nbytes - bytes_written);
 390                 if (retval < 1) {
 391                         syslog(LOG_ERR, "sysdep: client_write(%d bytes) failed: %m", nbytes - bytes_written);
 392                         client_close();
 393                         Ctx->kill_me = KILLME_WRITE_FAILED;
 394                         return -1;
 395                 }
 396                 bytes_written = bytes_written + retval;
 397         }
 398         return 0;
 399 }
 400
 401 void cputbuf(const StrBuf *Buf) {
 402         client_write(ChrPtr(Buf), StrLength(Buf));
 403 }
 404
 405
 406 // Send formatted printable data to the client.
 407 // Implemented in terms of client_write() so it's technically not sysdep...
 408 void cprintf(const char *format, ...) {
 409         va_list arg_ptr;
 410         char buf[1024];
 411
 412         va_start(arg_ptr, format);
 413         if (vsnprintf(buf, sizeof buf, format, arg_ptr) == -1)
 414                 buf[sizeof buf - 2] = '\n';
 415         client_write(buf, strlen(buf));
 416         va_end(arg_ptr);
 417 }
 418
 419
 420 // Read data from the client socket.
 421 //
 422 // sock         socket fd to read from
 423 // buf          buffer to read into
 424 // bytes        number of bytes to read
 425 // timeout      Number of seconds to wait before timing out
 426 //
 427 // Possible return values:
 428 //      1       Requested number of bytes has been read.
 429 //      0       Request timed out.
 430 //      -1      Connection is broken, or other error.
 431 int client_read_blob(StrBuf *Target, int bytes, int timeout) {
 432         CitContext *CCC=CC;
 433         const char *Error;
 434         int retval = 0;
 435
 436 #ifdef HAVE_OPENSSL
 437         if (CCC->redirect_ssl) {
 438                 retval = client_read_sslblob(Target, bytes, timeout);
 439                 if (retval < 0) {
 440                         syslog(LOG_ERR, "sysdep: client_read_blob() failed");
 441                 }
 442         }
 443         else
 444 #endif
 445         {
 446                 retval = StrBufReadBLOBBuffered(Target,
 447                                                 CCC->RecvBuf.Buf,
 448                                                 &CCC->RecvBuf.ReadWritePointer,
 449                                                 &CCC->client_socket,
 450                                                 1,
 451                                                 bytes,
 452                                                 O_TERM,
 453                                                 &Error
 454                 );
 455                 if (retval < 0) {
 456                         syslog(LOG_ERR, "sysdep: client_read_blob() failed: %s", Error);
 457                         client_close();
 458                         return retval;
 459                 }
 460         }
 461         return retval;
 462 }
 463
 464
 465 // to make client_read_random_blob() more efficient, increase buffer size.
 466 // just use in greeting function, else your buffer may be flushed
 467 void client_set_inbound_buf(long N)
 468 {
 469         CitContext *CCC=CC;
 470         FlushStrBuf(CCC->RecvBuf.Buf);
 471         ReAdjustEmptyBuf(CCC->RecvBuf.Buf, N * SIZ, N * SIZ);
 472 }
 473
 474 int client_read_random_blob(StrBuf *Target, int timeout)
 475 {
 476         CitContext *CCC=CC;
 477         int rc;
 478
 479         rc =  client_read_blob(Target, 1, timeout);
 480         if (rc > 0)
 481         {
 482                 long len;
 483                 const char *pch;
 484
 485                 len = StrLength(CCC->RecvBuf.Buf);
 486                 pch = ChrPtr(CCC->RecvBuf.Buf);
 487
 488                 if (len > 0)
 489                 {
 490                         if (CCC->RecvBuf.ReadWritePointer != NULL) {
 491                                 len -= CCC->RecvBuf.ReadWritePointer - pch;
 492                                 pch = CCC->RecvBuf.ReadWritePointer;
 493                         }
 494                         StrBufAppendBufPlain(Target, pch, len, 0);
 495                         FlushStrBuf(CCC->RecvBuf.Buf);
 496                         CCC->RecvBuf.ReadWritePointer = NULL;
 497                         return StrLength(Target);
 498                 }
 499                 return rc;
 500         }
 501         else
 502                 return rc;
 503 }
 504
 505 int client_read_to(char *buf, int bytes, int timeout)
 506 {
 507         CitContext *CCC=CC;
 508         int rc;
 509
 510         rc = client_read_blob(CCC->MigrateBuf, bytes, timeout);
 511         if (rc < 0)
 512         {
 513                 *buf = '\0';
 514                 return rc;
 515         }
 516         else
 517         {
 518                 memcpy(buf,
 519                        ChrPtr(CCC->MigrateBuf),
 520                        StrLength(CCC->MigrateBuf) + 1);
 521                 FlushStrBuf(CCC->MigrateBuf);
 522                 return rc;
 523         }
 524 }
 525
 526
 527 int HaveMoreLinesWaiting(CitContext *CCC) {
 528         if ((CCC->kill_me != 0) ||
 529             ( (CCC->RecvBuf.ReadWritePointer == NULL) &&
 530               (StrLength(CCC->RecvBuf.Buf) == 0) &&
 531               (CCC->client_socket != -1)) )
 532                 return 0;
 533         else
 534                 return 1;
 535 }
 536
 537
 538 // Read data from the client socket with default timeout.
 539 // (This is implemented in terms of client_read_to() and could be
 540 // justifiably moved out of sysdep.c)
 541 INLINE int client_read(char *buf, int bytes) {
 542         return(client_read_to(buf, bytes, CtdlGetConfigInt("c_sleeping")));
 543 }
 544
 545 int CtdlClientGetLine(StrBuf *Target) {
 546         CitContext *CCC=CC;
 547         const char *Error;
 548         int rc;
 549
 550         FlushStrBuf(Target);
 551 #ifdef HAVE_OPENSSL
 552         if (CCC->redirect_ssl) {
 553                 rc = client_readline_sslbuffer(Target, CCC->RecvBuf.Buf, &CCC->RecvBuf.ReadWritePointer, 1);
 554                 return rc;
 555         }
 556         else
 557 #endif
 558         {
 559                 rc = StrBufTCP_read_buffered_line_fast(Target,
 560                                                        CCC->RecvBuf.Buf,
 561                                                        &CCC->RecvBuf.ReadWritePointer,
 562                                                        &CCC->client_socket,
 563                                                        5,
 564                                                        1,
 565                                                        &Error
 566                 );
 567                 return rc;
 568         }
 569 }
 570
 571
 572 // Get a LF-terminated line of text from the client.
 573 // (This is implemented in terms of client_read() and could be
 574 // justifiably moved out of sysdep.c)
 575 int client_getln(char *buf, int bufsize) {
 576         int i, retval;
 577         CitContext *CCC=CC;
 578         const char *pCh;
 579
 580         retval = CtdlClientGetLine(CCC->MigrateBuf);
 581         if (retval < 0)
 582           return(retval >= 0);
 583
 584
 585         i = StrLength(CCC->MigrateBuf);
 586         pCh = ChrPtr(CCC->MigrateBuf);
 587         // Strip the trailing LF, and the trailing CR if present.
 588         if (bufsize <= i)
 589                 i = bufsize - 1;
 590         while ( (i > 0)
 591                 && ( (pCh[i - 1]==13)
 592                      || ( pCh[i - 1]==10)) ) {
 593                 i--;
 594         }
 595         memcpy(buf, pCh, i);
 596         buf[i] = 0;
 597
 598         FlushStrBuf(CCC->MigrateBuf);
 599         if (retval < 0) {
 600                 safestrncpy(&buf[i], "000", bufsize - i);
 601         }
 602         return(retval >= 0);
 603 }
 604
 605
 606 // Cleanup any contexts that are left lying around
 607 void close_masters(void) {
 608         struct ServiceFunctionHook *serviceptr;
 609         const char *Text;
 610
 611         // close all protocol master sockets
 612         for (serviceptr = ServiceHookTable; serviceptr != NULL;
 613             serviceptr = serviceptr->next ) {
 614
 615                 if (serviceptr->tcp_port > 0) {
 616                         if (serviceptr->msock == -1) {
 617                                 Text = "not closing again";
 618                         }
 619                         else {
 620                                 Text = "Closing";
 621                         }
 622                         syslog(LOG_INFO, "sysdep: %s %d listener on port %d",
 623                                Text,
 624                                serviceptr->msock,
 625                                serviceptr->tcp_port
 626                         );
 627                         serviceptr->tcp_port = 0;
 628                 }
 629
 630                 if (serviceptr->sockpath != NULL) {
 631                         if (serviceptr->msock == -1) {
 632                                 Text = "not closing again";
 633                         }
 634                         else {
 635                                 Text = "Closing";
 636                         }
 637                         syslog(LOG_INFO, "sysdep: %s %d listener on '%s'",
 638                                Text,
 639                                serviceptr->msock,
 640                                serviceptr->sockpath
 641                         );
 642                 }
 643
 644                 if (serviceptr->msock != -1) {
 645                         close(serviceptr->msock);
 646                         serviceptr->msock = -1;
 647                 }
 648
 649                 // If it's a Unix domain socket, remove the file.
 650                 if (serviceptr->sockpath != NULL) {
 651                         unlink(serviceptr->sockpath);
 652                         serviceptr->sockpath = NULL;
 653                 }
 654         }
 655 }
 656
 657
 658 // The system-dependent part of master_cleanup() - close the master socket.
 659 void sysdep_master_cleanup(void) {
 660         close_masters();
 661         context_cleanup();
 662 #ifdef HAVE_OPENSSL
 663         destruct_ssl();
 664 #endif
 665 }
 666
 667
 668
 669 pid_t current_child;
 670 void graceful_shutdown(int signum) {
 671         kill(current_child, signum);
 672         unlink(file_pid_file);
 673         exit(0);
 674 }
 675
 676 int nFireUps = 0;
 677 int nFireUpsNonRestart = 0;
 678 pid_t ForkedPid = 1;
 679
 680 // Start running as a daemon.
 681 void start_daemon(int unused) {
 682         int status = 0;
 683         pid_t child = 0;
 684         FILE *fp;
 685         int do_restart = 0;
 686         current_child = 0;
 687
 688         // Close stdin/stdout/stderr and replace them with /dev/null.
 689         // We don't just call close() because we don't want these fd's
 690         // to be reused for other files.
 691         child = fork();
 692         if (child != 0) {
 693                 exit(0);
 694         }
 695
 696         signal(SIGHUP, SIG_IGN);
 697         signal(SIGINT, SIG_IGN);
 698         signal(SIGQUIT, SIG_IGN);
 699
 700         setsid();
 701         umask(0);
 702         if (    (freopen("/dev/null", "r", stdin) != stdin) ||
 703                 (freopen("/dev/null", "w", stdout) != stdout) ||
 704                 (freopen("/dev/null", "w", stderr) != stderr)
 705         ) {
 706                 syslog(LOG_ERR, "sysdep: unable to reopen stdio: %m");
 707         }
 708
 709         do {
 710                 current_child = fork();
 711                 signal(SIGTERM, graceful_shutdown);
 712                 if (current_child < 0) {
 713                         perror("fork");
 714                         exit(errno);
 715                 }
 716                 else if (current_child == 0) {
 717                         return; // continue starting citadel.
 718                 }
 719                 else {
 720                         fp = fopen(file_pid_file, "w");
 721                         if (fp != NULL) {
 722                                 fprintf(fp, ""F_PID_T"\n", getpid());
 723                                 fclose(fp);
 724                         }
 725                         waitpid(current_child, &status, 0);
 726                 }
 727                 nFireUpsNonRestart = nFireUps;
 728
 729                 // Exit code 0 means the watcher should exit
 730                 if (WIFEXITED(status) && (WEXITSTATUS(status) == CTDLEXIT_SHUTDOWN)) {
 731                         do_restart = 0;
 732                 }
 733
 734                 // Exit code 101-109 means the watcher should exit
 735                 else if (WIFEXITED(status) && (WEXITSTATUS(status) >= 101) && (WEXITSTATUS(status) <= 109)) {
 736                         do_restart = 0;
 737                 }
 738
 739                 // Any other exit code, or no exit code, means we should restart.
 740                 else {
 741                         do_restart = 1;
 742                         nFireUps++;
 743                         ForkedPid = current_child;
 744                 }
 745
 746         } while (do_restart);
 747
 748         unlink(file_pid_file);
 749         exit(WEXITSTATUS(status));
 750 }
 751
 752
 753 void checkcrash(void) {
 754         if (nFireUpsNonRestart != nFireUps) {
 755                 StrBuf *CrashMail;
 756                 CrashMail = NewStrBuf();
 757                 syslog(LOG_ALERT, "sysdep: posting crash message");
 758                 StrBufPrintf(CrashMail,
 759                         " \n"
 760                         " The Citadel server process (citserver) terminated unexpectedly."
 761                         "\n \n"
 762                         " This could be the result of a bug in the server program, or some external "
 763                         "factor.\n \n"
 764                         " You can obtain more information about this by enabling core dumps.\n \n"
 765                         " For more information, please see:\n \n"
 766                         " http://citadel.org/doku.php?id=faq:mastering_your_os:gdb#how.do.i.make.my.system.produce.core-files"
 767                         "\n \n"
 768
 769                         " If you have already done this, the core dump is likely to be found at %score.%d\n"
 770                         ,
 771                         ctdl_run_dir, ForkedPid);
 772                 CtdlAideMessage(ChrPtr(CrashMail), "Citadel server process terminated unexpectedly");
 773                 FreeStrBuf(&CrashMail);
 774         }
 775 }
 776
 777
 778 // Generic routine to convert a login name to a full name (gecos)
 779 // Returns nonzero if a conversion took place
 780 int convert_login(char NameToConvert[]) {
 781         struct passwd *pw;
 782         unsigned int a;
 783
 784         pw = getpwnam(NameToConvert);
 785         if (pw == NULL) {
 786                 return(0);
 787         }
 788         else {
 789                 strcpy(NameToConvert, pw->pw_gecos);
 790                 for (a=0; a<strlen(NameToConvert); ++a) {
 791                         if (NameToConvert[a] == ',') NameToConvert[a] = 0;
 792                 }
 793                 return(1);
 794         }
 795 }
 796
 797
 798 void HuntBadSession(void) {
 799         int highest;
 800         CitContext *ptr;
 801         fd_set readfds;
 802         struct timeval tv;
 803         struct ServiceFunctionHook *serviceptr;
 804
 805         // Next, add all of the client sockets
 806         begin_critical_section(S_SESSION_TABLE);
 807         for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 808                 if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 809                         continue;
 810                 // Initialize the fdset.
 811                 FD_ZERO(&readfds);
 812                 highest = 0;
 813                 tv.tv_sec = 0;          // wake up every second if no input
 814                 tv.tv_usec = 0;
 815
 816                 // Don't select on dead sessions, only truly idle ones
 817                 if (    (ptr->state == CON_IDLE)
 818                         && (ptr->kill_me == 0)
 819                         && (ptr->client_socket > 0)
 820                 ) {
 821                         FD_SET(ptr->client_socket, &readfds);
 822                         if (ptr->client_socket > highest)
 823                                 highest = ptr->client_socket;
 824
 825                         if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) && (errno == EBADF))
 826                         {
 827                                 // Gotcha!
 828                                 syslog(LOG_ERR,
 829                                        "sysdep: killing session CC[%d] bad FD: [%d] User[%s] Host[%s:%s]",
 830                                         ptr->cs_pid,
 831                                         ptr->client_socket,
 832                                         ptr->curr_user,
 833                                         ptr->cs_host,
 834                                         ptr->cs_addr
 835                                 );
 836                                 ptr->kill_me = 1;
 837                                 ptr->client_socket = -1;
 838                                 break;
 839                         }
 840                 }
 841         }
 842         end_critical_section(S_SESSION_TABLE);
 843
 844         // First, add the various master sockets to the fdset.
 845         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 846
 847                 // Initialize the fdset.
 848                 highest = 0;
 849                 tv.tv_sec = 0;          // wake up every second if no input
 850                 tv.tv_usec = 0;
 851
 852                 FD_SET(serviceptr->msock, &readfds);
 853                 if (serviceptr->msock > highest) {
 854                         highest = serviceptr->msock;
 855                 }
 856                 if ((select(highest + 1, &readfds, NULL, NULL, &tv) < 0) &&
 857                     (errno == EBADF))
 858                 {
 859                         // Gotcha! server socket dead? commit suicide!
 860                         syslog(LOG_ERR, "sysdep: found bad FD: %d and its a server socket! Shutting Down!", serviceptr->msock);
 861                         server_shutting_down = 1;
 862                         break;
 863                 }
 864         }
 865 }
 866
 867
 868 // This loop just keeps going and going and going...
 869 void *worker_thread(void *blah) {
 870         int highest;
 871         CitContext *ptr;
 872         CitContext *bind_me = NULL;
 873         fd_set readfds;
 874         int retval = 0;
 875         struct timeval tv;
 876         int force_purge = 0;
 877         struct ServiceFunctionHook *serviceptr;
 878         int ssock;                      // Descriptor for client socket
 879         CitContext *con = NULL;         // Temporary context pointer
 880         int i;
 881
 882         pthread_mutex_lock(&ThreadCountMutex);
 883         ++num_workers;
 884         pthread_mutex_unlock(&ThreadCountMutex);
 885
 886         while (!server_shutting_down) {
 887
 888                 // make doubly sure we're not holding any stale db handles which might cause a deadlock
 889                 cdb_check_handles();
 890 do_select:      force_purge = 0;
 891                 bind_me = NULL;         // Which session shall we handle?
 892
 893                 // Initialize the fdset
 894                 FD_ZERO(&readfds);
 895                 highest = 0;
 896
 897                 // First, add the various master sockets to the fdset.
 898                 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
 899                         FD_SET(serviceptr->msock, &readfds);
 900                         if (serviceptr->msock > highest) {
 901                                 highest = serviceptr->msock;
 902                         }
 903                 }
 904
 905                 // Next, add all of the client sockets.
 906                 begin_critical_section(S_SESSION_TABLE);
 907                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
 908                         if ((ptr->state == CON_SYS) && (ptr->client_socket == 0))
 909                             continue;
 910
 911                         // Don't select on dead sessions, only truly idle ones
 912                         if (    (ptr->state == CON_IDLE)
 913                                 && (ptr->kill_me == 0)
 914                                 && (ptr->client_socket > 0)
 915                         ) {
 916                                 FD_SET(ptr->client_socket, &readfds);
 917                                 if (ptr->client_socket > highest)
 918                                         highest = ptr->client_socket;
 919                         }
 920                         if ((bind_me == NULL) && (ptr->state == CON_READY)) {
 921                                 bind_me = ptr;
 922                                 ptr->state = CON_EXECUTING;
 923                                 break;
 924                         }
 925                         if ((bind_me == NULL) && (ptr->state == CON_GREETING)) {
 926                                 bind_me = ptr;
 927                                 ptr->state = CON_STARTING;
 928                                 break;
 929                         }
 930                 }
 931                 end_critical_section(S_SESSION_TABLE);
 932
 933                 if (bind_me) {
 934                         goto SKIP_SELECT;
 935                 }
 936
 937                 // If we got this far, it means that there are no sessions
 938                 // which a previous thread marked for attention, so we go
 939                 // ahead and get ready to select().
 940
 941                 if (!server_shutting_down) {
 942                         tv.tv_sec = 1;          // wake up every second if no input
 943                         tv.tv_usec = 0;
 944                         retval = select(highest + 1, &readfds, NULL, NULL, &tv);
 945                 }
 946                 else {
 947                         --num_workers;
 948                         return NULL;
 949                 }
 950
 951                 // Now figure out who made this select() unblock.
 952                 // First, check for an error or exit condition.
 953                 if (retval < 0) {
 954                         if (errno == EBADF) {
 955                                 syslog(LOG_ERR, "sysdep: select() failed: %m");
 956                                 HuntBadSession();
 957                                 goto do_select;
 958                         }
 959                         if (errno != EINTR) {
 960                                 syslog(LOG_ERR, "sysdep: exiting: %m");
 961                                 server_shutting_down = 1;
 962                                 continue;
 963                         } else {
 964                                 if (server_shutting_down) {
 965                                         --num_workers;
 966                                         return(NULL);
 967                                 }
 968                                 goto do_select;
 969                         }
 970                 }
 971                 else if (retval == 0) {
 972                         if (server_shutting_down) {
 973                                 --num_workers;
 974                                 return(NULL);
 975                         }
 976                 }
 977
 978                 // Next, check to see if it's a new client connecting on a master socket.
 979
 980                 else if ((retval > 0) && (!server_shutting_down)) for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next) {
 981
 982                         if (FD_ISSET(serviceptr->msock, &readfds)) {
 983                                 ssock = accept(serviceptr->msock, NULL, 0);
 984                                 if (ssock >= 0) {
 985                                         syslog(LOG_DEBUG, "sysdep: new client socket %d", ssock);
 986
 987                                         // The master socket is non-blocking but the client
 988                                         // sockets need to be blocking, otherwise certain
 989                                         // operations barf on FreeBSD.  Not a fatal error.
 990                                         if (fcntl(ssock, F_SETFL, 0) < 0) {
 991                                                 syslog(LOG_ERR, "sysdep: Can't set socket to blocking: %m");
 992                                         }
 993
 994                                         // New context will be created already
 995                                         // set up in the CON_EXECUTING state.
 996                                         con = CreateNewContext();
 997
 998                                         // Assign our new socket number to it.
 999                                         con->tcp_port = serviceptr->tcp_port;
1000                                         con->client_socket = ssock;
1001                                         con->h_command_function = serviceptr->h_command_function;
1002                                         con->h_async_function = serviceptr->h_async_function;
1003                                         con->h_greeting_function = serviceptr->h_greeting_function;
1004                                         con->ServiceName = serviceptr->ServiceName;
1005
1006                                         // Connections on a local client are always from the same host
1007                                         if (serviceptr->sockpath != NULL) {
1008                                                 con->is_local_client = 1;
1009                                         }
1010
1011                                         // Set the SO_REUSEADDR socket option
1012                                         i = 1;
1013                                         setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
1014                                         con->state = CON_GREETING;
1015                                         retval--;
1016                                         if (retval == 0)
1017                                                 break;
1018                                 }
1019                         }
1020                 }
1021
1022                 // It must be a client socket.  Find a context that has data
1023                 // waiting on its socket *and* is in the CON_IDLE state.  Any
1024                 // active sockets other than our chosen one are marked as
1025                 // CON_READY so the next thread that comes around can just bind
1026                 // to one without having to select() again.
1027                 begin_critical_section(S_SESSION_TABLE);
1028                 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
1029                         int checkfd = ptr->client_socket;
1030                         if ((checkfd != -1) && (ptr->state == CON_IDLE) ){
1031                                 if (FD_ISSET(checkfd, &readfds)) {
1032                                         ptr->input_waiting = 1;
1033                                         if (!bind_me) {
1034                                                 bind_me = ptr;  // I choose you!
1035                                                 bind_me->state = CON_EXECUTING;
1036                                         }
1037                                         else {
1038                                                 ptr->state = CON_READY;
1039                                         }
1040                                 } else if ((ptr->is_async) && (ptr->async_waiting) && (ptr->h_async_function)) {
1041                                         if (!bind_me) {
1042                                                 bind_me = ptr;  // I choose you!
1043                                                 bind_me->state = CON_EXECUTING;
1044                                         }
1045                                         else {
1046                                                 ptr->state = CON_READY;
1047                                         }
1048                                 }
1049                         }
1050                 }
1051                 end_critical_section(S_SESSION_TABLE);
1052
1053 SKIP_SELECT:
1054                 // We're bound to a session
1055                 pthread_mutex_lock(&ThreadCountMutex);
1056                 ++active_workers;
1057                 pthread_mutex_unlock(&ThreadCountMutex);
1058
1059                 if (bind_me != NULL) {
1060                         become_session(bind_me);
1061
1062                         if (bind_me->state == CON_STARTING) {
1063                                 bind_me->state = CON_EXECUTING;
1064                                 begin_session(bind_me);
1065                                 bind_me->h_greeting_function();
1066                         }
1067                         // If the client has sent a command, execute it.
1068                         if (CC->input_waiting) {
1069                                 CC->h_command_function();
1070
1071                                 while (HaveMoreLinesWaiting(CC))
1072                                        CC->h_command_function();
1073
1074                                 CC->input_waiting = 0;
1075                         }
1076
1077                         // If there are asynchronous messages waiting and the client supports it, do those now
1078                         if ((CC->is_async) && (CC->async_waiting) && (CC->h_async_function != NULL)) {
1079                                 CC->h_async_function();
1080                                 CC->async_waiting = 0;
1081                         }
1082
1083                         force_purge = CC->kill_me;
1084                         become_session(NULL);
1085                         bind_me->state = CON_IDLE;
1086                 }
1087
1088                 dead_session_purge(force_purge);
1089                 do_housekeeping();
1090
1091                 pthread_mutex_lock(&ThreadCountMutex);
1092                 --active_workers;
1093                 if ((active_workers + CtdlGetConfigInt("c_min_workers") < num_workers) &&
1094                     (num_workers > CtdlGetConfigInt("c_min_workers")))
1095                 {
1096                         num_workers--;
1097                         pthread_mutex_unlock(&ThreadCountMutex);
1098                         return (NULL);
1099                 }
1100                 pthread_mutex_unlock(&ThreadCountMutex);
1101         }
1102
1103         // If control reaches this point, the server is shutting down
1104         pthread_mutex_lock(&ThreadCountMutex);
1105         --num_workers;
1106         pthread_mutex_unlock(&ThreadCountMutex);
1107         return(NULL);
1108 }
1109
1110
1111 // SyslogFacility()
1112 // Translate text facility name to syslog.h defined value.
1113 int SyslogFacility(char *name)
1114 {
1115         int i;
1116         struct
1117         {
1118                 int facility;
1119                 char *name;
1120         }   facTbl[] =
1121         {
1122                 {   LOG_KERN,   "kern"          },
1123                 {   LOG_USER,   "user"          },
1124                 {   LOG_MAIL,   "mail"          },
1125                 {   LOG_DAEMON, "daemon"        },
1126                 {   LOG_AUTH,   "auth"          },
1127                 {   LOG_SYSLOG, "syslog"        },
1128                 {   LOG_LPR,    "lpr"           },
1129                 {   LOG_NEWS,   "news"          },
1130                 {   LOG_UUCP,   "uucp"          },
1131                 {   LOG_LOCAL0, "local0"        },
1132                 {   LOG_LOCAL1, "local1"        },
1133                 {   LOG_LOCAL2, "local2"        },
1134                 {   LOG_LOCAL3, "local3"        },
1135                 {   LOG_LOCAL4, "local4"        },
1136                 {   LOG_LOCAL5, "local5"        },
1137                 {   LOG_LOCAL6, "local6"        },
1138                 {   LOG_LOCAL7, "local7"        },
1139                 {   0,            NULL          }
1140         };
1141         for(i = 0; facTbl[i].name != NULL; i++) {
1142                 if(!strcasecmp(name, facTbl[i].name))
1143                         return facTbl[i].facility;
1144         }
1145         return LOG_DAEMON;
1146 }