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