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