webcit/sysdep.c

   1 /*
   2  * WebCit "system dependent" code.
   3  *
   4  * Copyright (c) 1996-2021 by the citadel.org team
   5  *
   6  * This program is open source software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 3.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include "sysdep.h"
  16 #include <stdlib.h>
  17 #include <unistd.h>
  18 #include <stdio.h>
  19 #include <fcntl.h>
  20 #include <ctype.h>
  21 #include <signal.h>
  22 #include <sys/types.h>
  23 #include <sys/stat.h>
  24 #include <sys/wait.h>
  25 #include <sys/socket.h>
  26 #include <syslog.h>
  27 #include <sys/syslog.h>
  28 #include <time.h>
  29 #include <limits.h>
  30 #include <sys/resource.h>
  31 #include <netinet/in.h>
  32 #include <netinet/tcp.h>
  33 #include <arpa/inet.h>
  34 #include <netdb.h>
  35 #include <sys/un.h>
  36 #include <string.h>
  37 #include <pwd.h>
  38 #include <errno.h>
  39 #include <stdarg.h>
  40 #include <grp.h>
  41 #ifdef HAVE_PTHREAD_H
  42 #include <pthread.h>
  43 #endif
  44 #include "webcit.h"
  45 #include "sysdep.h"
  46
  47 #ifdef HAVE_SYS_SELECT_H
  48 #include <sys/select.h>
  49 #endif
  50
  51 #include "webserver.h"
  52 #include "modules_init.h"
  53 #if HAVE_BACKTRACE
  54 #include <execinfo.h>
  55 #endif
  56
  57 pthread_mutex_t Critters[MAX_SEMAPHORES];       /* Things needing locking */
  58 pthread_key_t MyConKey;                         /* TSD key for MyContext() */
  59 pthread_key_t MyReq;                            /* TSD key for MyReq() */
  60 int msock;                      /* master listening socket */
  61 int time_to_die = 0;            /* Nonzero if server is shutting down */
  62
  63 extern void *context_loop(ParsedHttpHdrs *Hdr);
  64 extern void *housekeeping_loop(void);
  65 extern void do_housekeeping(void);
  66
  67 char ctdl_key_dir[PATH_MAX]=SSL_DIR;
  68 char file_crpt_file_key[PATH_MAX]="";
  69 char file_crpt_file_csr[PATH_MAX]="";
  70 char file_crpt_file_cer[PATH_MAX]="";
  71 char file_etc_mimelist[PATH_MAX]="";
  72
  73 char etc_dir[PATH_MAX];
  74 char static_dir[PATH_MAX];              /* calculated on startup */
  75 char static_local_dir[PATH_MAX];                /* calculated on startup */
  76 char static_icon_dir[PATH_MAX];          /* where should we find our mime icons? */
  77 char  *static_dirs[]={                          /* needs same sort order as the web mapping */
  78         "./static",
  79         "./static.local",
  80         "./tiny_mce",
  81         "./static/webcit_icons"
  82 };
  83
  84 int ExitPipe[2];
  85 HashList *GZMimeBlackList = NULL; /* mimetypes which shouldn't be gzip compressed */
  86
  87 void LoadMimeBlacklist(void)
  88 {
  89         StrBuf *MimeBlackLine;
  90         IOBuffer IOB;
  91         eReadState state;
  92
  93         memset(&IOB, 0, sizeof(IOBuffer));
  94         IOB.fd = open(file_etc_mimelist, O_RDONLY);
  95
  96         IOB.Buf = NewStrBuf();
  97         MimeBlackLine = NewStrBuf();
  98         GZMimeBlackList = NewHash(1, NULL);
  99
 100         do
 101         {
 102                 state = StrBufChunkSipLine(MimeBlackLine, &IOB);
 103
 104                 switch (state)
 105                 {
 106                 case eMustReadMore:
 107                         if (StrBuf_read_one_chunk_callback(IOB.fd, 0, &IOB) <= 0)
 108                                 state = eReadFail;
 109                         break;
 110                 case eReadSuccess:
 111                         if ((StrLength(MimeBlackLine) > 1) &&
 112                             (*ChrPtr(MimeBlackLine) != '#'))
 113                         {
 114                                 Put(GZMimeBlackList, SKEY(MimeBlackLine),
 115                                     (void*) 1, reference_free_handler);
 116                         }
 117                         FlushStrBuf(MimeBlackLine);
 118                         break;
 119                 case eReadFail:
 120                         break;
 121                 case eBufferNotEmpty:
 122                         break;
 123                 }
 124         }
 125         while (state != eReadFail);
 126
 127         close(IOB.fd);
 128
 129         FreeStrBuf(&IOB.Buf);
 130         FreeStrBuf(&MimeBlackLine);
 131 }
 132
 133 void CheckGZipCompressionAllowed(const char *MimeType, long MLen)
 134 {
 135         void *v;
 136
 137         if (WC->Hdr->HR.gzip_ok)
 138             WC->Hdr->HR.gzip_ok = GetHash(GZMimeBlackList, MimeType, MLen, &v) == 0;
 139 }
 140
 141 void InitialiseSemaphores(void)
 142 {
 143         int i;
 144
 145         /* Set up a bunch of semaphores to be used for critical sections */
 146         for (i=0; i<MAX_SEMAPHORES; ++i) {
 147                 pthread_mutex_init(&Critters[i], NULL);
 148         }
 149
 150         if (pipe(ExitPipe))
 151         {
 152                 syslog(LOG_WARNING, "Failed to open exit pipe: %d [%s]\n",
 153                        errno,
 154                        strerror(errno));
 155
 156                 exit(-1);
 157         }
 158 }
 159
 160 /*
 161  * Obtain a semaphore lock to begin a critical section.
 162  */
 163 void begin_critical_section(int which_one)
 164 {
 165         pthread_mutex_lock(&Critters[which_one]);
 166 }
 167
 168 /*
 169  * Release a semaphore lock to end a critical section.
 170  */
 171 void end_critical_section(int which_one)
 172 {
 173         pthread_mutex_unlock(&Critters[which_one]);
 174 }
 175
 176
 177 void ShutDownWebcit(void)
 178 {
 179
 180         DeleteHash(&GZMimeBlackList);
 181         free_zone_directory ();
 182         icaltimezone_release_zone_tab ();
 183         icalmemory_free_ring ();
 184         ShutDownLibCitadel ();
 185         shutdown_modules ();
 186 #ifdef HAVE_OPENSSL
 187         if (is_https) {
 188                 shutdown_ssl();
 189         }
 190 #endif
 191 }
 192
 193 /*
 194  * Entry point for worker threads
 195  */
 196 void worker_entry(void)
 197 {
 198         int ssock;
 199         int i = 0;
 200         int fail_this_transaction = 0;
 201         ParsedHttpHdrs Hdr;
 202
 203         memset(&Hdr, 0, sizeof(ParsedHttpHdrs));
 204         Hdr.HR.eReqType = eGET;
 205         http_new_modules(&Hdr);
 206
 207         do {
 208                 /* Each worker thread blocks on accept() while waiting for something to do. */
 209                 fail_this_transaction = 0;
 210                 ssock = -1;
 211                 errno = EAGAIN;
 212                 do {
 213                         fd_set wset;
 214                         --num_threads_executing;
 215                         FD_ZERO(&wset);
 216                         FD_SET(msock, &wset);
 217                         FD_SET(ExitPipe[1], &wset);
 218
 219                         select(msock + 1, NULL, &wset, NULL, NULL);
 220                         if (time_to_die)
 221                                 break;
 222
 223                         ssock = accept(msock, NULL, 0);
 224                         ++num_threads_executing;
 225                         if (ssock < 0) fail_this_transaction = 1;
 226                 } while ((msock > 0) && (ssock < 0)  && (time_to_die == 0));
 227
 228                 if ((msock == -1)||(time_to_die))
 229                 {/* ok, we're going down. */
 230                         int shutdown = 0;
 231
 232                         /* The first thread to get here will have to do the cleanup.
 233                          * Make sure it's really just one.
 234                          */
 235                         begin_critical_section(S_SHUTDOWN);
 236                         if (msock == -1)
 237                         {
 238                                 msock = -2;
 239                                 shutdown = 1;
 240                         }
 241                         end_critical_section(S_SHUTDOWN);
 242                         if (shutdown == 1)
 243                         {/* we're the one to cleanup the mess. */
 244                                 http_destroy_modules(&Hdr);
 245                                 syslog(LOG_DEBUG, "I'm master shutdown: tagging sessions to be killed.\n");
 246                                 shutdown_sessions();
 247                                 syslog(LOG_DEBUG, "master shutdown: waiting for others\n");
 248                                 sleeeeeeeeeep(1); /* wait so some others might finish... */
 249                                 syslog(LOG_DEBUG, "master shutdown: cleaning up sessions\n");
 250                                 do_housekeeping();
 251                                 syslog(LOG_DEBUG, "master shutdown: cleaning up libical\n");
 252
 253                                 ShutDownWebcit();
 254
 255                                 syslog(LOG_DEBUG, "master shutdown exiting.\n");
 256                                 exit(0);
 257                         }
 258                         break;
 259                 }
 260                 if (ssock < 0 ) continue;
 261
 262                 check_thread_pool_size();
 263
 264                 /* Now do something. */
 265                 if (msock < 0) {
 266                         if (ssock > 0) close (ssock);
 267                         syslog(LOG_DEBUG, "in between.");
 268                         pthread_exit(NULL);
 269                 } else {
 270                         /* Got it? do some real work! */
 271                         /* Set the SO_REUSEADDR socket option */
 272                         i = 1;
 273                         setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 274
 275                         /* If we are an HTTPS server, go crypto now. */
 276 #ifdef HAVE_OPENSSL
 277                         if (is_https) {
 278                                 if (starttls(ssock) != 0) {
 279                                         fail_this_transaction = 1;
 280                                         close(ssock);
 281                                 }
 282                         }
 283                         else
 284 #endif
 285                         {
 286                                 int fdflags;
 287                                 fdflags = fcntl(ssock, F_GETFL);
 288                                 if (fdflags < 0)
 289                                         syslog(LOG_WARNING, "unable to get server socket flags! %s \n",
 290                                                 strerror(errno));
 291                                 fdflags = fdflags | O_NONBLOCK;
 292                                 if (fcntl(ssock, F_SETFL, fdflags) < 0)
 293                                         syslog(LOG_WARNING, "unable to set server socket nonblocking flags! %s \n",
 294                                                 strerror(errno));
 295                         }
 296
 297                         if (fail_this_transaction == 0) {
 298                                 Hdr.http_sock = ssock;
 299
 300                                 /* Perform an HTTP transaction... */
 301                                 context_loop(&Hdr);
 302
 303                                 /* Shut down SSL/TLS if required... */
 304 #ifdef HAVE_OPENSSL
 305                                 if (is_https) {
 306                                         endtls();
 307                                 }
 308 #endif
 309
 310                                 /* ...and close the socket. */
 311                                 if (Hdr.http_sock > 0) {
 312                                         lingering_close(ssock);
 313                                 }
 314                                 http_detach_modules(&Hdr);
 315
 316                         }
 317
 318                 }
 319
 320         } while (!time_to_die);
 321
 322         http_destroy_modules(&Hdr);
 323         syslog(LOG_DEBUG, "Thread exiting.\n");
 324         pthread_exit(NULL);
 325 }
 326
 327
 328 /*
 329  * Shut us down the regular way.
 330  * signum is the signal we want to forward
 331  */
 332 pid_t current_child;
 333 void graceful_shutdown_watcher(int signum) {
 334         syslog(LOG_INFO, "Watcher thread exiting.\n");
 335         write(ExitPipe[0], HKEY("                              "));
 336         kill(current_child, signum);
 337         if (signum != SIGHUP)
 338                 exit(0);
 339 }
 340
 341
 342 /*
 343  * Shut us down the regular way.
 344  * signum is the signal we want to forward
 345  */
 346 pid_t current_child;
 347 void graceful_shutdown(int signum) {
 348         FILE *FD;
 349         int fd;
 350
 351         syslog(LOG_INFO, "WebCit is being shut down on signal %d.\n", signum);
 352         fd = msock;
 353         msock = -1;
 354         time_to_die = 1;
 355         FD=fdopen(fd, "a+");
 356         fflush (FD);
 357         fclose (FD);
 358         close(fd);
 359         write(ExitPipe[0], HKEY("                              "));
 360 }
 361
 362
 363 /*
 364  * Start running as a daemon.
 365  */
 366 void start_daemon(char *pid_file)
 367 {
 368         int status = 0;
 369         pid_t child = 0;
 370         FILE *fp;
 371         int do_restart = 0;
 372
 373         current_child = 0;
 374
 375         /* Close stdin/stdout/stderr and replace them with /dev/null.
 376          * We don't just call close() because we don't want these fd's
 377          * to be reused for other files.
 378          */
 379         chdir("/");
 380
 381         signal(SIGHUP, SIG_IGN);
 382         signal(SIGINT, SIG_IGN);
 383         signal(SIGQUIT, SIG_IGN);
 384
 385         child = fork();
 386         if (child != 0) {
 387                 exit(0);
 388         }
 389
 390         setsid();
 391         umask(0);
 392         freopen("/dev/null", "r", stdin);
 393         freopen("/dev/null", "w", stdout);
 394         freopen("/dev/null", "w", stderr);
 395         signal(SIGTERM, graceful_shutdown_watcher);
 396         signal(SIGHUP, graceful_shutdown_watcher);
 397
 398         do {
 399                 current_child = fork();
 400
 401
 402                 if (current_child < 0) {
 403                         perror("fork");
 404                         ShutDownLibCitadel ();
 405                         exit(errno);
 406                 }
 407
 408                 else if (current_child == 0) {  /* child process */
 409                         signal(SIGHUP, graceful_shutdown);
 410
 411                         return; /* continue starting webcit. */
 412                 }
 413                 else { /* watcher process */
 414                         if (pid_file) {
 415                                 fp = fopen(pid_file, "w");
 416                                 if (fp != NULL) {
 417                                         fprintf(fp, "%d\n", getpid());
 418                                         fclose(fp);
 419                                 }
 420                         }
 421                         waitpid(current_child, &status, 0);
 422                 }
 423
 424                 do_restart = 0;
 425
 426                 /* Did the main process exit with an actual exit code? */
 427                 if (WIFEXITED(status)) {
 428
 429                         /* Exit code 0 means the watcher should exit */
 430                         if (WEXITSTATUS(status) == 0) {
 431                                 do_restart = 0;
 432                         }
 433
 434                         /* Exit code 101-109 means the watcher should exit */
 435                         else if ( (WEXITSTATUS(status) >= 101) && (WEXITSTATUS(status) <= 109) ) {
 436                                 do_restart = 0;
 437                         }
 438
 439                         /* Any other exit code means we should restart. */
 440                         else {
 441                                 do_restart = 1;
 442                         }
 443                 }
 444
 445                 /* Any other type of termination (signals, etc.) should also restart. */
 446                 else {
 447                         do_restart = 1;
 448                 }
 449
 450         } while (do_restart);
 451
 452         if (pid_file) {
 453                 unlink(pid_file);
 454         }
 455         ShutDownLibCitadel ();
 456         exit(WEXITSTATUS(status));
 457 }
 458
 459
 460 /*
 461  * Spawn an additional worker thread into the pool.
 462  */
 463 void spawn_another_worker_thread()
 464 {
 465         pthread_t SessThread;   /* Thread descriptor */
 466         pthread_attr_t attr;    /* Thread attributes */
 467         int ret;
 468
 469         ++num_threads_existing;
 470         ++num_threads_executing;
 471
 472         /* set attributes for the new thread */
 473         pthread_attr_init(&attr);
 474         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 475
 476         /*
 477          * Our per-thread stacks need to be bigger than the default size,
 478          * otherwise the MIME parser crashes on FreeBSD.
 479          */
 480         if ((ret = pthread_attr_setstacksize(&attr, 1024 * 1024))) {
 481                 syslog(LOG_WARNING, "pthread_attr_setstacksize: %s\n", strerror(ret));
 482                 pthread_attr_destroy(&attr);
 483         }
 484
 485         /* now create the thread */
 486         if (pthread_create(&SessThread, &attr, (void *(*)(void *)) worker_entry, NULL) != 0) {
 487                 syslog(LOG_WARNING, "Can't create thread: %s\n", strerror(errno));
 488         }
 489
 490         /* free up the attributes */
 491         pthread_attr_destroy(&attr);
 492 }
 493
 494
 495 void
 496 webcit_calc_dirs_n_files(int relh, const char *basedir, int home, char *webcitdir, char *relhome)
 497 {
 498         char dirbuffer[PATH_MAX]="";
 499         /* calculate all our path on a central place */
 500     /* where to keep our config */
 501
 502 #define COMPUTE_DIRECTORY(SUBDIR) memcpy(dirbuffer,SUBDIR, sizeof dirbuffer);\
 503         snprintf(SUBDIR,sizeof SUBDIR,  "%s%s%s%s%s%s%s", \
 504                          (home&!relh)?webcitdir:basedir, \
 505              ((basedir!=webcitdir)&(home&!relh))?basedir:"/", \
 506              ((basedir!=webcitdir)&(home&!relh))?"/":"", \
 507                          relhome, \
 508              (relhome[0]!='\0')?"/":"",\
 509                          dirbuffer,\
 510                          (dirbuffer[0]!='\0')?"/":"");
 511         basedir=RUNDIR;
 512         COMPUTE_DIRECTORY(socket_dir);
 513         basedir=WWWDIR "/static";
 514         COMPUTE_DIRECTORY(static_dir);
 515         basedir=WWWDIR "/static/icons";
 516         COMPUTE_DIRECTORY(static_icon_dir);
 517         basedir=WWWDIR "/static.local";
 518         COMPUTE_DIRECTORY(static_local_dir);
 519         StripSlashes(static_dir, 1);
 520         StripSlashes(static_icon_dir, 1);
 521         StripSlashes(static_local_dir, 1);
 522
 523         snprintf(file_crpt_file_key,
 524                  sizeof file_crpt_file_key,
 525                  "%s/citadel.key",
 526                  ctdl_key_dir);
 527         snprintf(file_crpt_file_csr,
 528                  sizeof file_crpt_file_csr,
 529                  "%s/citadel.csr",
 530                  ctdl_key_dir);
 531         snprintf(file_crpt_file_cer,
 532                  sizeof file_crpt_file_cer,
 533                  "%s/citadel.cer",
 534                  ctdl_key_dir);
 535
 536
 537         basedir=ETCDIR;
 538         COMPUTE_DIRECTORY(etc_dir);
 539         StripSlashes(etc_dir, 1);
 540         snprintf(file_etc_mimelist,
 541                  sizeof file_etc_mimelist,
 542                  "%s/nogz-mimetypes.txt",
 543                  etc_dir);
 544
 545         /* we should go somewhere we can leave our coredump, if enabled... */
 546         syslog(LOG_INFO, "Changing directory to %s\n", socket_dir);
 547         if (chdir(webcitdir) != 0) {
 548                 perror("chdir");
 549         }
 550 }
 551
 552 void drop_root(uid_t UID)
 553 {
 554         struct passwd pw, *pwp = NULL;
 555 #ifdef HAVE_GETPWUID_R
 556         char pwbuf[SIZ];
 557 #endif
 558
 559         /*
 560          * Now that we've bound the sockets, change to the Citadel user id and its
 561          * corresponding group ids
 562          */
 563         if (UID != -1) {
 564
 565 #ifdef HAVE_GETPWUID_R
 566 #ifdef SOLARIS_GETPWUID
 567                 pwp = getpwuid_r(UID, &pw, pwbuf, sizeof(pwbuf));
 568 #else /* SOLARIS_GETPWUID */
 569                 getpwuid_r(UID, &pw, pwbuf, sizeof(pwbuf), &pwp);
 570 #endif /* SOLARIS_GETPWUID */
 571 #else /* HAVE_GETPWUID_R */
 572                 pwp = NULL;
 573 #endif /* HAVE_GETPWUID_R */
 574
 575                 if (pwp == NULL)
 576                         syslog(LOG_CRIT, "WARNING: getpwuid(%d): %s\n"
 577                                 "Group IDs will be incorrect.\n", UID,
 578                                 strerror(errno));
 579                 else {
 580                         initgroups(pw.pw_name, pw.pw_gid);
 581                         if (setgid(pw.pw_gid))
 582                                 syslog(LOG_CRIT, "setgid(%ld): %s\n", (long)pw.pw_gid,
 583                                         strerror(errno));
 584                 }
 585                 syslog(LOG_INFO, "Changing uid to %ld\n", (long)UID);
 586                 if (setuid(UID) != 0) {
 587                         syslog(LOG_CRIT, "setuid() failed: %s\n", strerror(errno));
 588                 }
 589 #if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_DUMPABLE)
 590                 prctl(PR_SET_DUMPABLE, 1);
 591 #endif
 592         }
 593 }
 594
 595
 596 /*
 597  * print the actual stack frame.
 598  */
 599 void wc_backtrace(long LogLevel)
 600 {
 601 #ifdef HAVE_BACKTRACE
 602         void *stack_frames[50];
 603         size_t size, i;
 604         char **strings;
 605
 606
 607         size = backtrace(stack_frames, sizeof(stack_frames) / sizeof(void*));
 608         strings = backtrace_symbols(stack_frames, size);
 609         for (i = 0; i < size; i++) {
 610                 if (strings != NULL)
 611                         syslog(LogLevel, "%s\n", strings[i]);
 612                 else
 613                         syslog(LogLevel, "%p\n", stack_frames[i]);
 614         }
 615         free(strings);
 616 #endif
 617 }