citadel/server_main.c

   1 // citserver's main() function lives here.
   2 //
   3 // Copyright (c) 1987-2021 by the citadel.org team
   4 //
   5 // This program is open source software; you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License version 3.
   7 //
   8 // This program is distributed in the hope that it will be useful,
   9 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 // GNU General Public License for more details.
  12
  13 #include <stdlib.h>
  14 #include <unistd.h>
  15 #include <stdio.h>
  16 #include <sys/types.h>
  17 #include <sys/stat.h>
  18 #include <grp.h>
  19 #include <sys/file.h>
  20 #include <libcitadel.h>
  21 #include "citserver.h"
  22 #include "svn_revision.h"
  23 #include "modules_init.h"
  24 #include "config.h"
  25 #include "control.h"
  26 #include "serv_extensions.h"
  27 #include "citadel_dirs.h"
  28 #include "user_ops.h"
  29
  30 uid_t ctdluid = 0;
  31 const char *CitadelServiceUDS="citadel-UDS";
  32 const char *CitadelServiceTCP="citadel-TCP";
  33 int sanity_diag_mode = 0;
  34
  35
  36 /*
  37  * Create or remove a lock file, so we only have one Citadel Server running at a time.
  38  * Set 'op' to nonzero to lock, zero to unlock.
  39  */
  40 void ctdl_lockfile(int op) {
  41         static char lockfilename[PATH_MAX];
  42         static FILE *fp;
  43
  44         if (op) {
  45                 syslog(LOG_DEBUG, "main: creating lockfile");
  46                 snprintf(lockfilename, sizeof lockfilename, "%s/citadel.lock", ctdl_run_dir);
  47                 fp = fopen(lockfilename, "w");
  48                 if (!fp) {
  49                         syslog(LOG_ERR, "%s: %m", lockfilename);
  50                         exit(CTDLEXIT_DB);
  51                 }
  52                 if (flock(fileno(fp), (LOCK_EX|LOCK_NB)) != 0) {
  53                         syslog(LOG_ERR, "main: cannot lock %s , is another citserver running?", lockfilename);
  54                         exit(CTDLEXIT_DB);
  55                 }
  56                 return;
  57         }
  58
  59         syslog(LOG_DEBUG, "main: removing lockfile");
  60         unlink(lockfilename);
  61         flock(fileno(fp), LOCK_UN);
  62         fclose(fp);
  63 }
  64
  65
  66 /*
  67  * Here's where it all begins.
  68  */
  69 int main(int argc, char **argv) {
  70
  71         char facility[32];
  72         int a;                  // General-purpose variables
  73         struct passwd pw, *pwp = NULL;
  74         char pwbuf[SIZ];
  75         int drop_root_perms = 1;
  76         int max_log_level = LOG_INFO;
  77         char *ctdldir = CTDLDIR;
  78         int syslog_facility = LOG_DAEMON;
  79         uid_t u = 0;
  80         struct passwd *p = NULL;
  81 #ifdef HAVE_RUN_DIR
  82         struct stat filestats;
  83 #endif
  84
  85         /* Tell 'em who's in da house */
  86         syslog(LOG_INFO, " ");
  87         syslog(LOG_INFO, " ");
  88         syslog(LOG_INFO, "*** Citadel server engine ***\n");
  89         syslog(LOG_INFO, "Version %d (build %s) ***", REV_LEVEL, svn_revision());
  90         syslog(LOG_INFO, "Copyright (C) 1987-2021 by the Citadel development team.");
  91         syslog(LOG_INFO, " ");
  92         syslog(LOG_INFO, "This program is open source software: you can redistribute it and/or");
  93         syslog(LOG_INFO, "modify it under the terms of the GNU General Public License, version 3.");
  94         syslog(LOG_INFO, " ");
  95         syslog(LOG_INFO, "This program is distributed in the hope that it will be useful,");
  96         syslog(LOG_INFO, "but WITHOUT ANY WARRANTY; without even the implied warranty of");
  97         syslog(LOG_INFO, "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the");
  98         syslog(LOG_INFO, "GNU General Public License for more details.");
  99         syslog(LOG_INFO, " ");
 100         syslog(LOG_INFO, "%s", libcitadel_version_string());
 101
 102         /* parse command-line arguments */
 103         while ((a=getopt(argc, argv, "cl:dh:x:t:B:Dru:s:b:")) != EOF) switch(a) {
 104
 105                 // test this binary for compatibility and exit
 106                 case 'c':
 107                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
 108                         exit(0);
 109                         break;
 110
 111                 // identify the desired syslog facility
 112                 case 'l':
 113                         safestrncpy(facility, optarg, sizeof(facility));
 114                         syslog_facility = SyslogFacility(facility);
 115                         break;
 116
 117                 // run in the background if -d was specified
 118                 case 'd':
 119                         running_as_daemon = 1;
 120                         break;
 121
 122                 // specify the data directory
 123                 case 'h':
 124                         ctdldir = optarg;
 125                         break;
 126
 127                 // identify the desired logging severity level
 128                 case 'x':
 129                         max_log_level = atoi(optarg);
 130                         break;
 131
 132                 // deprecated
 133                 case 't':
 134                         break;
 135
 136                 // deprecated
 137                 case 'B':
 138                         break;
 139
 140                 // deprecated
 141                 case 'D':
 142                         break;
 143
 144                 // -r tells the server not to drop root permissions.
 145                 // Don't use this unless you know what you're doing.
 146                 case 'r':
 147                         drop_root_perms = 0;
 148                         break;
 149
 150                 // -u tells the server what uid to run under...
 151                 case 'u':
 152                         u = atoi(optarg);
 153                         if (u > 0) {
 154                                 ctdluid = u;
 155                         }
 156                         else {
 157                                 p = getpwnam(optarg);
 158                                 if (p) {
 159                                         u = p->pw_uid;
 160                                 }
 161                         }
 162                         if (u > 0) {
 163                                 ctdluid = u;
 164                         }
 165                         break;
 166
 167                 // -s tells the server to behave differently during sanity checks
 168                 case 's':
 169                         sanity_diag_mode = atoi(optarg);
 170                         break;
 171
 172                 case 'b':
 173                         backtrace_filename = strdup(optarg);
 174                         break;
 175
 176                 // any other parameter makes it crash and burn
 177                 default:
 178                         fprintf(stderr, "citserver: usage: "
 179                                         "citserver "
 180                                         "[-l LogFacility] "
 181                                         "[-x MaxLogLevel] "
 182                                         "[-d] [-r] "
 183                                         "[-u user] "
 184                                         "[-h HomeDir]\n"
 185                         );
 186                         exit(1);
 187         }
 188
 189         if (chdir(ctdldir) != 0) {
 190                 syslog(LOG_ERR, "main: unable to change directory to [%s]: %m", ctdldir);
 191                 exit(CTDLEXIT_HOME);
 192         }
 193         else {
 194                 syslog(LOG_INFO, "main: running in data directory %s", ctdldir);
 195         }
 196
 197         if ((ctdluid == 0) && (drop_root_perms == 0)) {
 198                 fprintf(stderr, "citserver: cannot determine user to run as; please specify -r or -u options\n");
 199                 exit(CTDLEXIT_UNUSER);
 200         }
 201
 202         /* Last ditch effort to determine the user name ... if there's a user called "citadel" then use that */
 203         if (ctdluid == 0) {
 204                 p = getpwnam("citadel");
 205                 if (!p) {
 206                         p = getpwnam("bbs");
 207                 }
 208                 if (!p) {
 209                         p = getpwnam("guest");
 210                 }
 211                 if (p) {
 212                         u = p->pw_uid;
 213                 }
 214                 if (u > 0) {
 215                         ctdluid = u;
 216                 }
 217         }
 218
 219         /* initialize the master context */
 220         InitializeMasterCC();
 221         InitializeMasterTSD();
 222
 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 }