citadel/server_main.c

   1 /*
   2  * citserver's main() function lives here.
   3  *
   4  * Copyright (c) 1987-2021 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 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <stdio.h>
  17 #include <sys/types.h>
  18 #include <sys/stat.h>
  19 #include <grp.h>
  20 #include <sys/file.h>
  21 #include <libcitadel.h>
  22 #include "citserver.h"
  23 #include "svn_revision.h"
  24 #include "modules_init.h"
  25 #include "config.h"
  26 #include "control.h"
  27 #include "serv_extensions.h"
  28 #include "citadel_dirs.h"
  29 #include "user_ops.h"
  30
  31 uid_t ctdluid = 0;
  32 const char *CitadelServiceUDS="citadel-UDS";
  33 const char *CitadelServiceTCP="citadel-TCP";
  34 int sanity_diag_mode = 0;
  35
  36
  37 /*
  38  * Create or remove a lock file, so we only have one Citadel Server running at a time.
  39  * Set 'op' to nonzero to lock, zero to unlock.
  40  */
  41 void ctdl_lockfile(int op) {
  42         static char lockfilename[PATH_MAX];
  43         static FILE *fp;
  44
  45         if (op) {
  46                 syslog(LOG_DEBUG, "main: creating lockfile");
  47                 snprintf(lockfilename, sizeof lockfilename, "%s/citadel.lock", ctdl_run_dir);
  48                 fp = fopen(lockfilename, "w");
  49                 if (!fp) {
  50                         syslog(LOG_ERR, "%s: %m", lockfilename);
  51                         exit(CTDLEXIT_DB);
  52                 }
  53                 if (flock(fileno(fp), (LOCK_EX|LOCK_NB)) != 0) {
  54                         syslog(LOG_ERR, "main: cannot lock %s , is another citserver running?", lockfilename);
  55                         exit(CTDLEXIT_DB);
  56                 }
  57                 return;
  58         }
  59
  60         syslog(LOG_DEBUG, "main: removing lockfile");
  61         unlink(lockfilename);
  62         flock(fileno(fp), LOCK_UN);
  63         fclose(fp);
  64 }
  65
  66
  67 /*
  68  * Here's where it all begins.
  69  */
  70 int main(int argc, char **argv) {
  71
  72         size_t basesize = 64;
  73         char facility[32];
  74         int a;                  /* General-purpose variables */
  75         struct passwd pw, *pwp = NULL;
  76         char pwbuf[SIZ];
  77         int drop_root_perms = 1;
  78         int max_log_level = LOG_INFO;
  79         char *ctdldir = CTDLDIR;
  80         int syslog_facility = LOG_DAEMON;
  81         uid_t u = 0;
  82         struct passwd *p = NULL;
  83 #ifdef HAVE_RUN_DIR
  84         struct stat filestats;
  85 #endif
  86
  87         /* Tell 'em who's in da house */
  88         syslog(LOG_INFO, " ");
  89         syslog(LOG_INFO, " ");
  90         syslog(LOG_INFO, "*** Citadel server engine ***\n");
  91         syslog(LOG_INFO, "Version %d (build %s) ***", REV_LEVEL, svn_revision());
  92         syslog(LOG_INFO, "Copyright (C) 1987-2021 by the Citadel development team.");
  93         syslog(LOG_INFO, " ");
  94         syslog(LOG_INFO, "This program is open source software: you can redistribute it and/or");
  95         syslog(LOG_INFO, "modify it under the terms of the GNU General Public License, version 3.");
  96         syslog(LOG_INFO, " ");
  97         syslog(LOG_INFO, "This program is distributed in the hope that it will be useful,");
  98         syslog(LOG_INFO, "but WITHOUT ANY WARRANTY; without even the implied warranty of");
  99         syslog(LOG_INFO, "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the");
 100         syslog(LOG_INFO, "GNU General Public License for more details.");
 101         syslog(LOG_INFO, " ");
 102         syslog(LOG_INFO, "%s", libcitadel_version_string());
 103
 104         /* parse command-line arguments */
 105         while ((a=getopt(argc, argv, "cl:dh:x:t:B:Dru:s:")) != EOF) switch(a) {
 106
 107                 // test this binary for compatibility and exit
 108                 case 'c':
 109                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
 110                         exit(0);
 111                         break;
 112
 113                 // identify the desired syslog facility
 114                 case 'l':
 115                         safestrncpy(facility, optarg, sizeof(facility));
 116                         syslog_facility = SyslogFacility(facility);
 117                         break;
 118
 119                 // run in the background if -d was specified
 120                 case 'd':
 121                         running_as_daemon = 1;
 122                         break;
 123
 124                 // specify the data directory
 125                 case 'h':
 126                         ctdldir = optarg;
 127                         break;
 128
 129                 // identify the desired logging severity level
 130                 case 'x':
 131                         max_log_level = atoi(optarg);
 132                         break;
 133
 134                 // deprecated
 135                 case 't':
 136                         break;
 137
 138                 // basesize (passed to libcitadel)
 139                 case 'B':
 140                         basesize = atoi(optarg);
 141                         break;
 142
 143                 // deprecated
 144                 case 'D':
 145                         break;
 146
 147                 // -r tells the server not to drop root permissions.
 148                 // Don't use this unless you know what you're doing.
 149                 case 'r':
 150                         drop_root_perms = 0;
 151                         break;
 152
 153                 // -u tells the server what uid to run under...
 154                 case 'u':
 155                         u = atoi(optarg);
 156                         if (u > 0) {
 157                                 ctdluid = u;
 158                         }
 159                         else {
 160                                 p = getpwnam(optarg);
 161                                 if (p) {
 162                                         u = p->pw_uid;
 163                                 }
 164                         }
 165                         if (u > 0) {
 166                                 ctdluid = u;
 167                         }
 168                         break;
 169
 170                 // -s tells the server to behave differently during sanity checks
 171                 case 's':
 172                         sanity_diag_mode = atoi(optarg);
 173                         break;
 174
 175                 // any other parameter makes it crash and burn
 176                 default:
 177                         fprintf(stderr, "citserver: usage: "
 178                                         "citserver "
 179                                         "[-l LogFacility] "
 180                                         "[-x MaxLogLevel] "
 181                                         "[-d] [-r] "
 182                                         "[-u user] "
 183                                         "[-h HomeDir]\n"
 184                         );
 185                         exit(1);
 186         }
 187
 188         if (chdir(ctdldir) != 0) {
 189                 syslog(LOG_ERR, "main: unable to change directory to [%s]: %m", ctdldir);
 190                 exit(CTDLEXIT_HOME);
 191         }
 192         else {
 193                 syslog(LOG_INFO, "main: running in data directory %s", ctdldir);
 194         }
 195
 196         if ((ctdluid == 0) && (drop_root_perms == 0)) {
 197                 fprintf(stderr, "citserver: cannot determine user to run as; please specify -r or -u options\n");
 198                 exit(CTDLEXIT_UNUSER);
 199         }
 200
 201         /* Last ditch effort to determine the user name ... if there's a user called "citadel" then use that */
 202         if (ctdluid == 0) {
 203                 p = getpwnam("citadel");
 204                 if (!p) {
 205                         p = getpwnam("bbs");
 206                 }
 207                 if (!p) {
 208                         p = getpwnam("guest");
 209                 }
 210                 if (p) {
 211                         u = p->pw_uid;
 212                 }
 213                 if (u > 0) {
 214                         ctdluid = u;
 215                 }
 216         }
 217
 218         /* initialize the master context */
 219         InitializeMasterCC();
 220         InitializeMasterTSD();
 221
 222         StartLibCitadel(basesize);
 223         setlogmask(LOG_UPTO(max_log_level));
 224         openlog("citserver",
 225                 ( running_as_daemon ? (LOG_PID) : (LOG_PID | LOG_PERROR) ),
 226                 syslog_facility
 227         );
 228
 229         /* daemonize, if we were asked to */
 230         if (running_as_daemon) {
 231                 start_daemon(0);
 232                 drop_root_perms = 1;
 233         }
 234
 235         if ((mkdir(ctdl_run_dir, 0755) != 0) && (errno != EEXIST)) {
 236                 syslog(LOG_ERR, "main: unable to create run directory [%s]: %m", ctdl_run_dir);
 237         }
 238
 239         if (chown(ctdl_run_dir, ctdluid, (pwp==NULL)?-1:pw.pw_gid) != 0) {
 240                 syslog(LOG_ERR, "main: unable to set the access rights for [%s]: %m", ctdl_run_dir);
 241         }
 242
 243         ctdl_lockfile(1);
 244         init_sysdep();                                          // Initialize...
 245         master_startup();                                       // Do non system dependent startup functions
 246         check_control();                                        // Check/sanitize/initialize control record, fix user indexes
 247         syslog(LOG_INFO, "main: upgrading modules");            // Run any upgrade entry points
 248         upgrade_modules();
 249
 250         /*
 251          * Load the user for the masterCC or create them if they don't exist
 252          */
 253         if (CtdlGetUser(&masterCC.user, "SYS_Citadel")) {
 254                 /* User doesn't exist. We can't use create user here as the user number needs to be 0 */
 255                 strcpy (masterCC.user.fullname, "SYS_Citadel") ;
 256                 CtdlPutUser(&masterCC.user);
 257                 CtdlGetUser(&masterCC.user, "SYS_Citadel");     /* Just to be safe */
 258         }
 259
 260         /*
 261          * Bind the server to a Unix-domain socket (user client access)
 262          */
 263         CtdlRegisterServiceHook(0,
 264                                 file_citadel_socket,
 265                                 citproto_begin_session,
 266                                 do_command_loop,
 267                                 do_async_loop,
 268                                 CitadelServiceUDS);
 269
 270         /*
 271          * Bind the server to a Unix-domain socket (admin client access)
 272          */
 273         CtdlRegisterServiceHook(0,
 274                                 file_citadel_admin_socket,
 275                                 citproto_begin_admin_session,
 276                                 do_command_loop,
 277                                 do_async_loop,
 278                                 CitadelServiceUDS);
 279         chmod(file_citadel_admin_socket, S_IRWXU);      /* for your eyes only */
 280
 281         /*
 282          * Bind the server to our favorite TCP port (usually 504).
 283          */
 284         CtdlRegisterServiceHook(CtdlGetConfigInt("c_port_number"),
 285                                 NULL,
 286                                 citproto_begin_session,
 287                                 do_command_loop,
 288                                 do_async_loop,
 289                                 CitadelServiceTCP);
 290
 291         /*
 292          * Load any server-side extensions available here.
 293          */
 294         syslog(LOG_INFO, "main: initializing server extensions");
 295         initialise_modules(0);
 296
 297         /*
 298          * If we need host auth, start our chkpwd daemon.
 299          */
 300         if (CtdlGetConfigInt("c_auth_mode") == AUTHMODE_HOST) {
 301                 start_chkpwd_daemon();
 302         }
 303
 304         /*
 305          * check, whether we're fired up another time after a crash.
 306          * if, post an aide message, so the admin has a chance to react.
 307          */
 308         checkcrash();
 309
 310         /*
 311          * Now that we've bound the sockets, change to the Citadel user id and its corresponding group ids
 312          */
 313         if (drop_root_perms) {
 314                 cdb_chmod_data();       /* make sure we own our data files */
 315                 getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf), &pwp);
 316                 if (pwp == NULL)
 317                         syslog(LOG_ERR, "main: WARNING, getpwuid(%ld): %m Group IDs will be incorrect.", (long)CTDLUID);
 318                 else {
 319                         initgroups(pw.pw_name, pw.pw_gid);
 320                         if (setgid(pw.pw_gid)) {
 321                                 syslog(LOG_ERR, "main: setgid(%ld): %m", (long)pw.pw_gid);
 322                         }
 323                 }
 324                 syslog(LOG_INFO, "main: changing uid to %ld", (long)CTDLUID);
 325                 if (setuid(CTDLUID) != 0) {
 326                         syslog(LOG_ERR, "main: setuid() failed: %m");
 327                 }
 328 #if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_DUMPABLE)
 329                 prctl(PR_SET_DUMPABLE, 1);
 330 #endif
 331         }
 332
 333         /* We want to check for idle sessions once per minute */
 334         CtdlRegisterSessionHook(terminate_idle_sessions, EVT_TIMER, PRIO_CLEANUP + 1);
 335
 336         /* Go into multithreaded mode.  When this call exits, the server is stopping. */
 337         go_threading();
 338
 339         /* Get ready to shut down the server. */
 340         int exit_code = master_cleanup(exit_signal);
 341         ctdl_lockfile(0);
 342         if (restart_server) {
 343                 syslog(LOG_INFO, "main: *** CITADEL SERVER IS RESTARTING ***");
 344                 execv(argv[0], argv);
 345         }
 346         return(exit_code);
 347 }