citadel/server/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 "modules_init.h"
  23 #include "config.h"
  24 #include "control.h"
  25 #include "serv_extensions.h"
  26 #include "citadel_dirs.h"
  27 #include "user_ops.h"
  28
  29 uid_t ctdluid = 0;
  30 const char *CitadelServiceUDS="citadel-UDS";
  31 const char *CitadelServiceTCP="citadel-TCP";
  32 int sanity_diag_mode = 0;
  33
  34
  35 // Create or remove a lock file, so we only have one Citadel Server running at a time.
  36 // Set 'op' to nonzero to lock, zero to unlock.
  37 void ctdl_lockfile(int op) {
  38         static char lockfilename[PATH_MAX];
  39         static FILE *fp;
  40
  41         if (op) {
  42                 syslog(LOG_DEBUG, "main: creating lockfile");
  43                 snprintf(lockfilename, sizeof lockfilename, "%s/citadel.lock", ctdl_run_dir);
  44                 fp = fopen(lockfilename, "w");
  45                 if (!fp) {
  46                         syslog(LOG_ERR, "%s: %m", lockfilename);
  47                         exit(CTDLEXIT_DB);
  48                 }
  49                 if (flock(fileno(fp), (LOCK_EX|LOCK_NB)) != 0) {
  50                         syslog(LOG_ERR, "main: cannot lock %s , is another citserver running?", lockfilename);
  51                         exit(CTDLEXIT_DB);
  52                 }
  53                 return;
  54         }
  55
  56         syslog(LOG_DEBUG, "main: removing lockfile");
  57         unlink(lockfilename);
  58         flock(fileno(fp), LOCK_UN);
  59         fclose(fp);
  60 }
  61
  62
  63 // Here's where it all begins.
  64 int main(int argc, char **argv) {
  65
  66         char facility[32];
  67         int a;                  // General-purpose variables
  68         struct passwd pw, *pwp = NULL;
  69         char pwbuf[SIZ];
  70         int drop_root_perms = 1;
  71         int max_log_level = LOG_INFO;
  72         char *ctdldir = CTDLDIR;
  73         int syslog_facility = LOG_DAEMON;
  74         uid_t u = 0;
  75         struct passwd *p = NULL;
  76 #ifdef HAVE_RUN_DIR
  77         struct stat filestats;
  78 #endif
  79
  80         // Tell 'em who's in da house
  81         syslog(LOG_INFO, " ");
  82         syslog(LOG_INFO, " ");
  83         syslog(LOG_INFO, "*** Citadel server engine ***\n");
  84         syslog(LOG_INFO, "Version %d (build %s) ***", REV_LEVEL, BUILD_ID);
  85         syslog(LOG_INFO, "Copyright (C) 1987-2022 by the Citadel development team.");
  86         syslog(LOG_INFO, " ");
  87         syslog(LOG_INFO, "This program is open source software: you can redistribute it and/or");
  88         syslog(LOG_INFO, "modify it under the terms of the GNU General Public License, version 3.");
  89         syslog(LOG_INFO, " ");
  90         syslog(LOG_INFO, "This program is distributed in the hope that it will be useful,");
  91         syslog(LOG_INFO, "but WITHOUT ANY WARRANTY; without even the implied warranty of");
  92         syslog(LOG_INFO, "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the");
  93         syslog(LOG_INFO, "GNU General Public License for more details.");
  94         syslog(LOG_INFO, " ");
  95         syslog(LOG_INFO, "%s", libcitadel_version_string());
  96
  97         // parse command-line arguments
  98         while ((a=getopt(argc, argv, "cl:dh:x:t:B:Dru:s:")) != EOF) switch(a) {
  99
 100                 // test this binary for compatibility and exit
 101                 case 'c':
 102                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
 103                         exit(0);
 104                         break;
 105
 106                 // identify the desired syslog facility
 107                 case 'l':
 108                         safestrncpy(facility, optarg, sizeof(facility));
 109                         syslog_facility = SyslogFacility(facility);
 110                         break;
 111
 112                 // run in the background if -d was specified
 113                 case 'd':
 114                         running_as_daemon = 1;
 115                         break;
 116
 117                 // specify the data directory
 118                 case 'h':
 119                         ctdldir = optarg;
 120                         break;
 121
 122                 // identify the desired logging severity level
 123                 case 'x':
 124                         max_log_level = atoi(optarg);
 125                         break;
 126
 127                 // deprecated
 128                 case 't':
 129                         break;
 130
 131                 // deprecated
 132                 case 'B':
 133                         break;
 134
 135                 // deprecated
 136                 case 'D':
 137                         break;
 138
 139                 // -r tells the server not to drop root permissions.
 140                 // Don't use this unless you know what you're doing.
 141                 case 'r':
 142                         drop_root_perms = 0;
 143                         break;
 144
 145                 // -u tells the server what uid to run under...
 146                 case 'u':
 147                         u = atoi(optarg);
 148                         if (u > 0) {
 149                                 ctdluid = u;
 150                         }
 151                         else {
 152                                 p = getpwnam(optarg);
 153                                 if (p) {
 154                                         u = p->pw_uid;
 155                                 }
 156                         }
 157                         if (u > 0) {
 158                                 ctdluid = u;
 159                         }
 160                         break;
 161
 162                 // -s tells the server to behave differently during sanity checks
 163                 case 's':
 164                         sanity_diag_mode = atoi(optarg);
 165                         break;
 166
 167                 // any other parameter makes it crash and burn
 168                 default:
 169                         fprintf(stderr, "citserver: usage: "
 170                                         "citserver "
 171                                         "[-l LogFacility] "
 172                                         "[-x MaxLogLevel] "
 173                                         "[-d] [-r] "
 174                                         "[-u user] "
 175                                         "[-h HomeDir]\n"
 176                         );
 177                         exit(1);
 178         }
 179
 180         if (chdir(ctdldir) != 0) {
 181                 syslog(LOG_ERR, "main: unable to change directory to [%s]: %m", ctdldir);
 182                 exit(CTDLEXIT_HOME);
 183         }
 184         else {
 185                 syslog(LOG_INFO, "main: running in data directory %s", ctdldir);
 186         }
 187
 188         if ((ctdluid == 0) && (drop_root_perms == 0)) {
 189                 fprintf(stderr, "citserver: cannot determine user to run as; please specify -r or -u options\n");
 190                 exit(CTDLEXIT_UNUSER);
 191         }
 192
 193         // Last ditch effort to determine the user name ... if there's a user called "citadel" then use that
 194         if (ctdluid == 0) {
 195                 p = getpwnam("citadel");
 196                 if (!p) {
 197                         p = getpwnam("bbs");
 198                 }
 199                 if (!p) {
 200                         p = getpwnam("guest");
 201                 }
 202                 if (p) {
 203                         u = p->pw_uid;
 204                 }
 205                 if (u > 0) {
 206                         ctdluid = u;
 207                 }
 208         }
 209
 210         // initialize the master context
 211         InitializeMasterCC();
 212         InitializeMasterTSD();
 213
 214         setlogmask(LOG_UPTO(max_log_level));
 215         openlog("citserver",
 216                 ( running_as_daemon ? (LOG_PID) : (LOG_PID | LOG_PERROR) ),
 217                 syslog_facility
 218         );
 219
 220         // daemonize, if we were asked to
 221         if (running_as_daemon) {
 222                 start_daemon(0);
 223                 drop_root_perms = 1;
 224         }
 225
 226         if ((mkdir(ctdl_run_dir, 0755) != 0) && (errno != EEXIST)) {
 227                 syslog(LOG_ERR, "main: unable to create run directory [%s]: %m", ctdl_run_dir);
 228         }
 229
 230         if (chown(ctdl_run_dir, ctdluid, (pwp==NULL)?-1:pw.pw_gid) != 0) {
 231                 syslog(LOG_ERR, "main: unable to set the access rights for [%s]: %m", ctdl_run_dir);
 232         }
 233
 234         ctdl_lockfile(1);
 235         init_sysdep();                                          // Initialize...
 236         master_startup();                                       // Do non system dependent startup functions
 237         check_control();                                        // Check/sanitize/initialize control record, fix user indexes
 238         syslog(LOG_INFO, "main: upgrading modules");            // Run any upgrade entry points
 239         pre_startup_upgrades();
 240
 241         // Load the user for the masterCC or create them if they don't exist
 242         if (CtdlGetUser(&masterCC.user, "SYS_Citadel")) {
 243                 // User doesn't exist. We can't use create user here as the user number needs to be 0
 244                 strcpy (masterCC.user.fullname, "SYS_Citadel") ;
 245                 CtdlPutUser(&masterCC.user);
 246                 CtdlGetUser(&masterCC.user, "SYS_Citadel");     // Just to be safe
 247         }
 248
 249         // Bind the server to a Unix-domain socket (user client access)
 250         CtdlRegisterServiceHook(0,
 251                                 file_citadel_socket,
 252                                 citproto_begin_session,
 253                                 do_command_loop,
 254                                 do_async_loop,
 255                                 CitadelServiceUDS);
 256
 257         // Bind the server to a Unix-domain socket (admin client access)
 258         CtdlRegisterServiceHook(0,
 259                                 file_citadel_admin_socket,
 260                                 citproto_begin_admin_session,
 261                                 do_command_loop,
 262                                 do_async_loop,
 263                                 CitadelServiceUDS);
 264         chmod(file_citadel_admin_socket, S_IRWXU);      // for your eyes only
 265
 266         // Bind the server to our favorite TCP port (usually 504).
 267         CtdlRegisterServiceHook(CtdlGetConfigInt("c_port_number"),
 268                                 NULL,
 269                                 citproto_begin_session,
 270                                 do_command_loop,
 271                                 do_async_loop,
 272                                 CitadelServiceTCP);
 273
 274         // Load any server-side extensions available here.
 275         syslog(LOG_INFO, "main: initializing server extensions");
 276         initialize_modules(0);
 277
 278         // If we need host auth, start our chkpwd daemon.
 279         if (CtdlGetConfigInt("c_auth_mode") == AUTHMODE_HOST) {
 280                 start_chkpwd_daemon();
 281         }
 282
 283         // check, whether we're fired up another time after a crash.
 284         // if, post an aide message, so the admin has a chance to react.
 285         checkcrash();
 286
 287         // Now that we've bound the sockets, change to the Citadel user id and its corresponding group ids
 288         if (drop_root_perms) {
 289                 cdb_chmod_data();       // make sure we own our data files
 290                 getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf), &pwp);
 291                 if (pwp == NULL)
 292                         syslog(LOG_ERR, "main: WARNING, getpwuid(%ld): %m Group IDs will be incorrect.", (long)CTDLUID);
 293                 else {
 294                         initgroups(pw.pw_name, pw.pw_gid);
 295                         if (setgid(pw.pw_gid)) {
 296                                 syslog(LOG_ERR, "main: setgid(%ld): %m", (long)pw.pw_gid);
 297                         }
 298                 }
 299                 syslog(LOG_INFO, "main: changing uid to %ld", (long)CTDLUID);
 300                 if (setuid(CTDLUID) != 0) {
 301                         syslog(LOG_ERR, "main: setuid() failed: %m");
 302                 }
 303 #if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_DUMPABLE)
 304                 prctl(PR_SET_DUMPABLE, 1);
 305 #endif
 306         }
 307
 308         // We want to check for idle sessions once per minute
 309         CtdlRegisterSessionHook(terminate_idle_sessions, EVT_TIMER, PRIO_CLEANUP + 1);
 310
 311         // Go into multithreaded mode.  When this call exits, the server is stopping.
 312         go_threading();
 313
 314         // Get ready to shut down the server.
 315         int exit_code = master_cleanup(exit_signal);
 316         ctdl_lockfile(0);
 317         if (restart_server) {
 318                 syslog(LOG_INFO, "main: *** CITADEL SERVER IS RESTARTING ***");
 319                 execv(argv[0], argv);
 320         }
 321         return(exit_code);
 322 }