citadel/server_main.c

   1 // citserver's main() function lives here.
   2 //
   3 // Copyright (c) 1987-2022 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 // Create or remove a lock file, so we only have one Citadel Server running at a time.
  37 // Set 'op' to nonzero to lock, zero to unlock.
  38 void ctdl_lockfile(int op) {
  39         static char lockfilename[PATH_MAX];
  40         static FILE *fp;
  41
  42         if (op) {
  43                 syslog(LOG_DEBUG, "main: creating lockfile");
  44                 snprintf(lockfilename, sizeof lockfilename, "%s/citadel.lock", ctdl_run_dir);
  45                 fp = fopen(lockfilename, "w");
  46                 if (!fp) {
  47                         syslog(LOG_ERR, "%s: %m", lockfilename);
  48                         exit(CTDLEXIT_DB);
  49                 }
  50                 if (flock(fileno(fp), (LOCK_EX|LOCK_NB)) != 0) {
  51                         syslog(LOG_ERR, "main: cannot lock %s , is another citserver running?", lockfilename);
  52                         exit(CTDLEXIT_DB);
  53                 }
  54                 return;
  55         }
  56
  57         syslog(LOG_DEBUG, "main: removing lockfile");
  58         unlink(lockfilename);
  59         flock(fileno(fp), LOCK_UN);
  60         fclose(fp);
  61 }
  62
  63
  64 // Here's where it all begins.
  65 int main(int argc, char **argv) {
  66
  67         char facility[32];
  68         int a;                  // General-purpose variables
  69         struct passwd pw, *pwp = NULL;
  70         char pwbuf[SIZ];
  71         int drop_root_perms = 1;
  72         int max_log_level = LOG_INFO;
  73         char *ctdldir = CTDLDIR;
  74         int syslog_facility = LOG_DAEMON;
  75         uid_t u = 0;
  76         struct passwd *p = NULL;
  77 #ifdef HAVE_RUN_DIR
  78         struct stat filestats;
  79 #endif
  80
  81         // Tell 'em who's in da house
  82         syslog(LOG_INFO, " ");
  83         syslog(LOG_INFO, " ");
  84         syslog(LOG_INFO, "*** Citadel server engine ***\n");
  85         syslog(LOG_INFO, "Version %d (build %s) ***", REV_LEVEL, svn_revision());
  86         syslog(LOG_INFO, "Copyright (C) 1987-2022 by the Citadel development team.");
  87         syslog(LOG_INFO, " ");
  88         syslog(LOG_INFO, "This program is open source software: you can redistribute it and/or");
  89         syslog(LOG_INFO, "modify it under the terms of the GNU General Public License, version 3.");
  90         syslog(LOG_INFO, " ");
  91         syslog(LOG_INFO, "This program is distributed in the hope that it will be useful,");
  92         syslog(LOG_INFO, "but WITHOUT ANY WARRANTY; without even the implied warranty of");
  93         syslog(LOG_INFO, "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the");
  94         syslog(LOG_INFO, "GNU General Public License for more details.");
  95         syslog(LOG_INFO, " ");
  96         syslog(LOG_INFO, "%s", libcitadel_version_string());
  97
  98         // parse command-line arguments
  99         while ((a=getopt(argc, argv, "cl:dh:x:t:B:Dru:s:")) != EOF) switch(a) {
 100
 101                 // test this binary for compatibility and exit
 102                 case 'c':
 103                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
 104                         exit(0);
 105                         break;
 106
 107                 // identify the desired syslog facility
 108                 case 'l':
 109                         safestrncpy(facility, optarg, sizeof(facility));
 110                         syslog_facility = SyslogFacility(facility);
 111                         break;
 112
 113                 // run in the background if -d was specified
 114                 case 'd':
 115                         running_as_daemon = 1;
 116                         break;
 117
 118                 // specify the data directory
 119                 case 'h':
 120                         ctdldir = optarg;
 121                         break;
 122
 123                 // identify the desired logging severity level
 124                 case 'x':
 125                         max_log_level = atoi(optarg);
 126                         break;
 127
 128                 // deprecated
 129                 case 't':
 130                         break;
 131
 132                 // deprecated
 133                 case 'B':
 134                         break;
 135
 136                 // deprecated
 137                 case 'D':
 138                         break;
 139
 140                 // -r tells the server not to drop root permissions.
 141                 // Don't use this unless you know what you're doing.
 142                 case 'r':
 143                         drop_root_perms = 0;
 144                         break;
 145
 146                 // -u tells the server what uid to run under...
 147                 case 'u':
 148                         u = atoi(optarg);
 149                         if (u > 0) {
 150                                 ctdluid = u;
 151                         }
 152                         else {
 153                                 p = getpwnam(optarg);
 154                                 if (p) {
 155                                         u = p->pw_uid;
 156                                 }
 157                         }
 158                         if (u > 0) {
 159                                 ctdluid = u;
 160                         }
 161                         break;
 162
 163                 // -s tells the server to behave differently during sanity checks
 164                 case 's':
 165                         sanity_diag_mode = atoi(optarg);
 166                         break;
 167
 168                 // any other parameter makes it crash and burn
 169                 default:
 170                         fprintf(stderr, "citserver: usage: "
 171                                         "citserver "
 172                                         "[-l LogFacility] "
 173                                         "[-x MaxLogLevel] "
 174                                         "[-d] [-r] "
 175                                         "[-u user] "
 176                                         "[-h HomeDir]\n"
 177                         );
 178                         exit(1);
 179         }
 180
 181         if (chdir(ctdldir) != 0) {
 182                 syslog(LOG_ERR, "main: unable to change directory to [%s]: %m", ctdldir);
 183                 exit(CTDLEXIT_HOME);
 184         }
 185         else {
 186                 syslog(LOG_INFO, "main: running in data directory %s", ctdldir);
 187         }
 188
 189         if ((ctdluid == 0) && (drop_root_perms == 0)) {
 190                 fprintf(stderr, "citserver: cannot determine user to run as; please specify -r or -u options\n");
 191                 exit(CTDLEXIT_UNUSER);
 192         }
 193
 194         // Last ditch effort to determine the user name ... if there's a user called "citadel" then use that
 195         if (ctdluid == 0) {
 196                 p = getpwnam("citadel");
 197                 if (!p) {
 198                         p = getpwnam("bbs");
 199                 }
 200                 if (!p) {
 201                         p = getpwnam("guest");
 202                 }
 203                 if (p) {
 204                         u = p->pw_uid;
 205                 }
 206                 if (u > 0) {
 207                         ctdluid = u;
 208                 }
 209         }
 210
 211         // initialize the master context
 212         InitializeMasterCC();
 213         InitializeMasterTSD();
 214
 215         setlogmask(LOG_UPTO(max_log_level));
 216         openlog("citserver",
 217                 ( running_as_daemon ? (LOG_PID) : (LOG_PID | LOG_PERROR) ),
 218                 syslog_facility
 219         );
 220
 221         // daemonize, if we were asked to
 222         if (running_as_daemon) {
 223                 start_daemon(0);
 224                 drop_root_perms = 1;
 225         }
 226
 227         if ((mkdir(ctdl_run_dir, 0755) != 0) && (errno != EEXIST)) {
 228                 syslog(LOG_ERR, "main: unable to create run directory [%s]: %m", ctdl_run_dir);
 229         }
 230
 231         if (chown(ctdl_run_dir, ctdluid, (pwp==NULL)?-1:pw.pw_gid) != 0) {
 232                 syslog(LOG_ERR, "main: unable to set the access rights for [%s]: %m", ctdl_run_dir);
 233         }
 234
 235         ctdl_lockfile(1);
 236         init_sysdep();                                          // Initialize...
 237         master_startup();                                       // Do non system dependent startup functions
 238         check_control();                                        // Check/sanitize/initialize control record, fix user indexes
 239         syslog(LOG_INFO, "main: upgrading modules");            // Run any upgrade entry points
 240         upgrade_modules();
 241
 242         // Load the user for the masterCC or create them if they don't exist
 243         if (CtdlGetUser(&masterCC.user, "SYS_Citadel")) {
 244                 // User doesn't exist. We can't use create user here as the user number needs to be 0
 245                 strcpy (masterCC.user.fullname, "SYS_Citadel") ;
 246                 CtdlPutUser(&masterCC.user);
 247                 CtdlGetUser(&masterCC.user, "SYS_Citadel");     // Just to be safe
 248         }
 249
 250         // Bind the server to a Unix-domain socket (user client access)
 251         CtdlRegisterServiceHook(0,
 252                                 file_citadel_socket,
 253                                 citproto_begin_session,
 254                                 do_command_loop,
 255                                 do_async_loop,
 256                                 CitadelServiceUDS);
 257
 258         // Bind the server to a Unix-domain socket (admin client access)
 259         CtdlRegisterServiceHook(0,
 260                                 file_citadel_admin_socket,
 261                                 citproto_begin_admin_session,
 262                                 do_command_loop,
 263                                 do_async_loop,
 264                                 CitadelServiceUDS);
 265         chmod(file_citadel_admin_socket, S_IRWXU);      // for your eyes only
 266
 267         // Bind the server to our favorite TCP port (usually 504).
 268         CtdlRegisterServiceHook(CtdlGetConfigInt("c_port_number"),
 269                                 NULL,
 270                                 citproto_begin_session,
 271                                 do_command_loop,
 272                                 do_async_loop,
 273                                 CitadelServiceTCP);
 274
 275         // Load any server-side extensions available here.
 276         syslog(LOG_INFO, "main: initializing server extensions");
 277         initialise_modules(0);
 278
 279         // If we need host auth, start our chkpwd daemon.
 280         if (CtdlGetConfigInt("c_auth_mode") == AUTHMODE_HOST) {
 281                 start_chkpwd_daemon();
 282         }
 283
 284         // check, whether we're fired up another time after a crash.
 285         // if, post an aide message, so the admin has a chance to react.
 286         checkcrash();
 287
 288         // Now that we've bound the sockets, change to the Citadel user id and its corresponding group ids
 289         if (drop_root_perms) {
 290                 cdb_chmod_data();       // make sure we own our data files
 291                 getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf), &pwp);
 292                 if (pwp == NULL)
 293                         syslog(LOG_ERR, "main: WARNING, getpwuid(%ld): %m Group IDs will be incorrect.", (long)CTDLUID);
 294                 else {
 295                         initgroups(pw.pw_name, pw.pw_gid);
 296                         if (setgid(pw.pw_gid)) {
 297                                 syslog(LOG_ERR, "main: setgid(%ld): %m", (long)pw.pw_gid);
 298                         }
 299                 }
 300                 syslog(LOG_INFO, "main: changing uid to %ld", (long)CTDLUID);
 301                 if (setuid(CTDLUID) != 0) {
 302                         syslog(LOG_ERR, "main: setuid() failed: %m");
 303                 }
 304 #if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_DUMPABLE)
 305                 prctl(PR_SET_DUMPABLE, 1);
 306 #endif
 307         }
 308
 309         // We want to check for idle sessions once per minute
 310         CtdlRegisterSessionHook(terminate_idle_sessions, EVT_TIMER, PRIO_CLEANUP + 1);
 311
 312         // Go into multithreaded mode.  When this call exits, the server is stopping.
 313         go_threading();
 314
 315         // Get ready to shut down the server.
 316         int exit_code = master_cleanup(exit_signal);
 317         ctdl_lockfile(0);
 318         if (restart_server) {
 319                 syslog(LOG_INFO, "main: *** CITADEL SERVER IS RESTARTING ***");
 320                 execv(argv[0], argv);
 321         }
 322         return(exit_code);
 323 }