citadel/server/server_main.c

   1 // citserver's main() function lives here.
   2 //
   3 // Copyright (c) 1987-2023 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 #include <stdlib.h>
   9 #include <unistd.h>
  10 #include <stdio.h>
  11 #include <sys/types.h>
  12 #include <sys/stat.h>
  13 #include <grp.h>
  14 #include <sys/file.h>
  15 #include <libcitadel.h>
  16 #include "citserver.h"
  17 #include "modules_init.h"
  18 #include "config.h"
  19 #include "control.h"
  20 #include "serv_extensions.h"
  21 #include "citadel_dirs.h"
  22 #include "user_ops.h"
  23
  24 uid_t ctdluid = 0;
  25 const char *CitadelServiceUDS="citadel-UDS";
  26 const char *CitadelServiceTCP="citadel-TCP";
  27 int sanity_diag_mode = 0;
  28
  29
  30 // Create or remove a lock file, so we only have one Citadel Server running at a time.
  31 // Set 'op' to nonzero to lock, zero to unlock.
  32 void ctdl_lockfile(int op) {
  33         static char lockfilename[PATH_MAX];
  34         static FILE *fp;
  35
  36         if (op) {
  37                 syslog(LOG_DEBUG, "main: creating lockfile");
  38                 snprintf(lockfilename, sizeof lockfilename, "%s/citadel.lock", ctdl_run_dir);
  39                 fp = fopen(lockfilename, "w");
  40                 if (!fp) {
  41                         syslog(LOG_ERR, "%s: %m", lockfilename);
  42                         exit(CTDLEXIT_DB);
  43                 }
  44                 if (flock(fileno(fp), (LOCK_EX|LOCK_NB)) != 0) {
  45                         syslog(LOG_ERR, "main: cannot lock %s (is another citserver running?)", lockfilename);
  46                         exit(CTDLEXIT_DB);
  47                 }
  48                 return;
  49         }
  50
  51         syslog(LOG_DEBUG, "main: removing lockfile");
  52         unlink(lockfilename);
  53         flock(fileno(fp), LOCK_UN);
  54         fclose(fp);
  55 }
  56
  57
  58 // Here's where it all begins.
  59 int main(int argc, char **argv) {
  60
  61         char facility[32];
  62         struct passwd pw, *pwp = NULL;
  63         char pwbuf[SIZ];
  64         int drop_root_perms = 1;
  65         int max_log_level = LOG_INFO;
  66         char *ctdldir = CTDLDIR;
  67         int syslog_facility = LOG_DAEMON;
  68         uid_t u = 0;
  69         struct passwd *p = NULL;
  70 #ifdef HAVE_RUN_DIR
  71         struct stat filestats;
  72 #endif
  73
  74         // Tell 'em who's in da house
  75         syslog(LOG_INFO, " ");
  76         syslog(LOG_INFO, " ");
  77         syslog(LOG_INFO, "*** Citadel server engine ***\n");
  78         syslog(LOG_INFO, "Version %d (build %s) ***", REV_LEVEL, BUILD_ID);
  79         syslog(LOG_INFO, "Copyright (C) 1987-2023 by the Citadel development team.");
  80         syslog(LOG_INFO, " ");
  81         syslog(LOG_INFO, "This program is open source software.  Use, duplication, or disclosure");
  82         syslog(LOG_INFO, "is subject to the terms of the GNU General Public License, version 3.");
  83         syslog(LOG_INFO, " ");
  84         syslog(LOG_INFO, "%s", libcitadel_version_string());
  85
  86         // parse command-line arguments
  87         int g;
  88         while ((g=getopt(argc, argv, "cl:dh:x:t:B:Dru:s:")) != EOF) switch(g) {
  89
  90                 // test this binary for compatibility and exit
  91                 case 'c':
  92                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
  93                         exit(0);
  94                         break;
  95
  96                 // identify the desired syslog facility
  97                 case 'l':
  98                         safestrncpy(facility, optarg, sizeof(facility));
  99                         syslog_facility = SyslogFacility(facility);
 100                         break;
 101
 102                 // run in the background if -d was specified
 103                 case 'd':
 104                         running_as_daemon = 1;
 105                         break;
 106
 107                 // specify the data directory
 108                 case 'h':
 109                         ctdldir = optarg;
 110                         break;
 111
 112                 // identify the desired logging severity level
 113                 case 'x':
 114                         max_log_level = atoi(optarg);
 115                         break;
 116
 117                 // deprecated flags from old versions -- ignore silently to prevent breaking scripts
 118                 case 't':
 119                 case 'B':
 120                 case 'D':
 121                         break;
 122
 123                 // -r tells the server not to drop root permissions.
 124                 // Don't use this unless you know what you're doing.
 125                 case 'r':
 126                         drop_root_perms = 0;
 127                         break;
 128
 129                 // -u tells the server what uid to run under...
 130                 case 'u':
 131                         u = atoi(optarg);
 132                         if (u > 0) {
 133                                 ctdluid = u;
 134                         }
 135                         else {
 136                                 p = getpwnam(optarg);
 137                                 if (p) {
 138                                         u = p->pw_uid;
 139                                 }
 140                         }
 141                         if (u > 0) {
 142                                 ctdluid = u;
 143                         }
 144                         break;
 145
 146                 // -s tells the server to behave differently during sanity checks
 147                 case 's':
 148                         sanity_diag_mode = atoi(optarg);
 149                         break;
 150
 151                 // any other parameter makes it crash and burn
 152                 default:
 153                         fprintf(stderr, "citserver: usage: "
 154                                         "citserver "
 155                                         "[-l LogFacility] "
 156                                         "[-x MaxLogLevel] "
 157                                         "[-d] [-r] "
 158                                         "[-u user] "
 159                                         "[-h HomeDir]\n"
 160                         );
 161                         exit(1);
 162         }
 163
 164         if (chdir(ctdldir) != 0) {
 165                 syslog(LOG_ERR, "main: unable to change directory to [%s]: %m", ctdldir);
 166                 exit(CTDLEXIT_HOME);
 167         }
 168         else {
 169                 syslog(LOG_INFO, "main: running in data directory %s", ctdldir);
 170         }
 171
 172         if ((ctdluid == 0) && (drop_root_perms == 0)) {
 173                 fprintf(stderr, "citserver: cannot determine user to run as; please specify -r or -u options\n");
 174                 exit(CTDLEXIT_UNUSER);
 175         }
 176
 177         // Last ditch effort to determine the user name ... if there's a user called "citadel" then use that
 178         if (ctdluid == 0) {
 179                 p = getpwnam("citadel");
 180                 if (!p) {
 181                         p = getpwnam("bbs");
 182                 }
 183                 if (!p) {
 184                         p = getpwnam("guest");
 185                 }
 186                 if (p) {
 187                         u = p->pw_uid;
 188                 }
 189                 if (u > 0) {
 190                         ctdluid = u;
 191                 }
 192         }
 193
 194         // initialize the master context
 195         InitializeMasterCC();
 196         InitializeMasterTSD();
 197
 198         setlogmask(LOG_UPTO(max_log_level));
 199         openlog("citserver",
 200                 ( running_as_daemon ? (LOG_PID) : (LOG_PID | LOG_PERROR) ),
 201                 syslog_facility
 202         );
 203
 204         // daemonize, if we were asked to
 205         if (running_as_daemon) {
 206                 start_daemon(0);
 207                 drop_root_perms = 1;
 208         }
 209
 210         if ((mkdir(ctdl_run_dir, 0755) != 0) && (errno != EEXIST)) {
 211                 syslog(LOG_ERR, "main: unable to create run directory [%s]: %m", ctdl_run_dir);
 212         }
 213
 214         if (chown(ctdl_run_dir, ctdluid, (pwp==NULL)?-1:pw.pw_gid) != 0) {
 215                 syslog(LOG_ERR, "main: unable to set the access rights for [%s]: %m", ctdl_run_dir);
 216         }
 217
 218         ctdl_lockfile(1);
 219         init_sysdep();                                          // Initialize...
 220         master_startup();                                       // Do non system dependent startup functions
 221         check_control();                                        // Check/sanitize/initialize control record, fix user indexes
 222         syslog(LOG_INFO, "main: upgrading modules");            // Run any upgrade entry points
 223         pre_startup_upgrades();
 224
 225         // Load the user for the masterCC or create them if they don't exist
 226         if (CtdlGetUser(&masterCC.user, "SYS_Citadel")) {
 227                 // User doesn't exist. We can't use create user here as the user number needs to be 0
 228                 strcpy(masterCC.user.fullname, "SYS_Citadel") ;
 229                 CtdlPutUser(&masterCC.user);
 230                 CtdlGetUser(&masterCC.user, "SYS_Citadel");     // Just to be safe
 231         }
 232
 233         // Bind the server to a Unix-domain socket (user client access)
 234         CtdlRegisterServiceHook(0,
 235                                 file_citadel_socket,
 236                                 citproto_begin_session,
 237                                 do_command_loop,
 238                                 do_async_loop,
 239                                 CitadelServiceUDS);
 240
 241         // Bind the server to a Unix-domain socket (admin client access)
 242         CtdlRegisterServiceHook(0,
 243                                 file_citadel_admin_socket,
 244                                 citproto_begin_admin_session,
 245                                 do_command_loop,
 246                                 do_async_loop,
 247                                 CitadelServiceUDS);
 248         chmod(file_citadel_admin_socket, S_IRWXU);              // protect the admin socket - it offers high privilege
 249
 250         // Bind the server to our favorite TCP port (usually 504).
 251         CtdlRegisterServiceHook(CtdlGetConfigInt("c_port_number"),
 252                                 NULL,
 253                                 citproto_begin_session,
 254                                 do_command_loop,
 255                                 do_async_loop,
 256                                 CitadelServiceTCP);
 257
 258         // Load any server-side extensions available here.
 259         syslog(LOG_INFO, "main: initializing server extensions");
 260         initialize_modules(0);
 261
 262         // If we need host auth, start our chkpwd daemon.
 263         if (CtdlGetConfigInt("c_auth_mode") == AUTHMODE_HOST) {
 264                 start_chkpwd_daemon();
 265         }
 266
 267         // check, whether we're fired up another time after a crash.
 268         // if, post an aide message, so the admin has a chance to react.
 269         checkcrash();
 270
 271         // Now that we've bound the sockets, change to the Citadel user id and its corresponding group ids
 272         if (drop_root_perms) {
 273                 cdb_chmod_data();       // make sure we own our data files
 274                 getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf), &pwp);
 275                 if (pwp == NULL) {
 276                         syslog(LOG_ERR, "main: WARNING, getpwuid(%ld): %m Group IDs will be incorrect.", (long)CTDLUID);
 277                 }
 278                 else {
 279                         initgroups(pw.pw_name, pw.pw_gid);
 280                         if (setgid(pw.pw_gid)) {
 281                                 syslog(LOG_ERR, "main: setgid(%ld): %m", (long)pw.pw_gid);
 282                         }
 283                 }
 284                 syslog(LOG_INFO, "main: changing uid to %ld", (long)CTDLUID);
 285                 if (setuid(CTDLUID) != 0) {
 286                         syslog(LOG_ERR, "main: setuid() failed: %m");
 287                 }
 288 #if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_DUMPABLE)
 289                 prctl(PR_SET_DUMPABLE, 1);
 290 #endif
 291         }
 292
 293         // We want to check for idle sessions once per minute
 294         CtdlRegisterSessionHook(terminate_idle_sessions, EVT_TIMER, PRIO_CLEANUP + 1);
 295
 296         // Go into multithreaded mode.  When this call exits, the server is stopping.
 297         go_threading();
 298
 299         // Get ready to shut down the server.
 300         int exit_code = master_cleanup(exit_signal);
 301         ctdl_lockfile(0);
 302         if (restart_server) {
 303                 syslog(LOG_INFO, "main: *** CITADEL SERVER IS RESTARTING ***");
 304                 execv(argv[0], argv);
 305         }
 306         return(exit_code);
 307 }