webcit/sysdep.c

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