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 char *rescue_string = NULL;
  29
  30
  31 // Create or remove a lock file, so we only have one Citadel Server running at a time.
  32 // Set 'op' to nonzero to lock, zero to unlock.
  33 void ctdl_lockfile(int op) {
  34         static char lockfilename[PATH_MAX];
  35         static FILE *fp;
  36
  37         if (op) {
  38                 syslog(LOG_DEBUG, "main: creating lockfile");
  39                 snprintf(lockfilename, sizeof lockfilename, "%s/citadel.lock", ctdl_run_dir);
  40                 fp = fopen(lockfilename, "w");
  41                 if (!fp) {
  42                         syslog(LOG_ERR, "%s: %m", lockfilename);
  43                         exit(CTDLEXIT_DB);
  44                 }
  45                 if (flock(fileno(fp), (LOCK_EX|LOCK_NB)) != 0) {
  46                         syslog(LOG_ERR, "main: cannot lock %s (is another citserver running?)", lockfilename);
  47                         exit(CTDLEXIT_DB);
  48                 }
  49                 return;
  50         }
  51
  52         syslog(LOG_DEBUG, "main: removing lockfile");
  53         unlink(lockfilename);
  54         flock(fileno(fp), LOCK_UN);
  55         fclose(fp);
  56 }
  57
  58
  59 // Here's where it all begins.
  60 int main(int argc, char **argv) {
  61
  62         char facility[32];
  63         struct passwd pw, *pwp = NULL;
  64         char pwbuf[SIZ];
  65         int drop_root_perms = 1;
  66         int max_log_level = LOG_INFO;
  67         char *ctdldir = CTDLDIR;
  68         int syslog_facility = LOG_DAEMON;
  69         uid_t u = 0;
  70         struct passwd *p = NULL;
  71 #ifdef HAVE_RUN_DIR
  72         struct stat filestats;
  73 #endif
  74
  75         // Tell 'em who's in da house
  76         syslog(LOG_INFO, " ");
  77         syslog(LOG_INFO, " ");
  78         syslog(LOG_INFO, "*** Citadel server engine ***\n");
  79         syslog(LOG_INFO, "Version %d (build %s) ***", REV_LEVEL, BUILD_ID);
  80         syslog(LOG_INFO, "Copyright (C) 1987-2023 by the Citadel development team.");
  81         syslog(LOG_INFO, " ");
  82         syslog(LOG_INFO, "This program is open source software.  Use, duplication, or disclosure");
  83         syslog(LOG_INFO, "is subject to the terms of the GNU General Public License, version 3.");
  84         syslog(LOG_INFO, " ");
  85         syslog(LOG_INFO, "%s", libcitadel_version_string());
  86
  87         // parse command-line arguments
  88         int g;
  89         while ((g=getopt(argc, argv, "cl:dh:x:t:B:Dru:s:R:")) != EOF) switch(g) {
  90
  91                 // test this binary for compatibility and exit
  92                 case 'c':
  93                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
  94                         exit(0);
  95                         break;
  96
  97                 // identify the desired syslog facility
  98                 case 'l':
  99                         safestrncpy(facility, optarg, sizeof(facility));
 100                         syslog_facility = SyslogFacility(facility);
 101                         break;
 102
 103                 // run in the background if -d was specified
 104                 case 'd':
 105                         running_as_daemon = 1;
 106                         break;
 107
 108                 // specify the data directory
 109                 case 'h':
 110                         ctdldir = optarg;
 111                         break;
 112
 113                 // identify the desired logging severity level
 114                 case 'x':
 115                         max_log_level = atoi(optarg);
 116                         break;
 117
 118                 // deprecated flags from old versions -- ignore silently to prevent breaking scripts
 119                 case 't':
 120                 case 'B':
 121                 case 'D':
 122                         break;
 123
 124                 // -r tells the server not to drop root permissions.
 125                 // Don't use this unless you know what you're doing.
 126                 case 'r':
 127                         drop_root_perms = 0;
 128                         break;
 129
 130                 // -u tells the server what uid to run under...
 131                 case 'u':
 132                         u = atoi(optarg);
 133                         if (u > 0) {
 134                                 ctdluid = u;
 135                         }
 136                         else {
 137                                 p = getpwnam(optarg);
 138                                 if (p) {
 139                                         u = p->pw_uid;
 140                                 }
 141                         }
 142                         if (u > 0) {
 143                                 ctdluid = u;
 144                         }
 145                         break;
 146
 147                 // -s tells the server to behave differently during sanity checks
 148                 case 's':
 149                         sanity_diag_mode = atoi(optarg);
 150                         break;
 151
 152                 // -R is an undocumented rescue mode that you should never use
 153                 case 'R':
 154                         rescue_string = strdup(optarg);
 155                         break;
 156
 157                 // any other parameter makes it crash and burn
 158                 default:
 159                         fprintf(stderr, "citserver: usage: "
 160                                         "citserver "
 161                                         "[-l LogFacility] "
 162                                         "[-x MaxLogLevel] "
 163                                         "[-d] [-r] "
 164                                         "[-u user] "
 165                                         "[-h HomeDir]\n"
 166                         );
 167                         exit(1);
 168         }
 169
 170         if (chdir(ctdldir) != 0) {
 171                 syslog(LOG_ERR, "main: unable to change directory to [%s]: %m", ctdldir);
 172                 exit(CTDLEXIT_HOME);
 173         }
 174         else {
 175                 syslog(LOG_INFO, "main: running in data directory %s", ctdldir);
 176         }
 177
 178         if ((ctdluid == 0) && (drop_root_perms == 0)) {
 179                 fprintf(stderr, "citserver: cannot determine user to run as; please specify -r or -u options\n");
 180                 exit(CTDLEXIT_UNUSER);
 181         }
 182
 183         // Last ditch effort to determine the user name ... if there's a user called "citadel" then use that
 184         if (ctdluid == 0) {
 185                 p = getpwnam("citadel");
 186                 if (!p) {
 187                         p = getpwnam("bbs");
 188                 }
 189                 if (!p) {
 190                         p = getpwnam("guest");
 191                 }
 192                 if (p) {
 193                         u = p->pw_uid;
 194                 }
 195                 if (u > 0) {
 196                         ctdluid = u;
 197                 }
 198         }
 199
 200         // initialize the master context
 201         InitializeMasterCC();
 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         // Setting this key to nonzero causes the server to regenerate all data that can be derived
 231         // from other tables: usersbynumber, directory, fulltext.
 232         // The import utility (ctdlload) sets this key.
 233         if (CtdlGetConfigInt("regenerate_secondary_indices") != 0) {
 234                 regenerate_secondary_indices();
 235         }
 236
 237
 238         // Load the user for the masterCC or create them if they don't exist
 239         if (CtdlGetUser(&masterCC.user, "SYS_Citadel")) {
 240                 // User doesn't exist. We can't use create user here as the user number needs to be 0
 241                 strcpy(masterCC.user.fullname, "SYS_Citadel") ;
 242                 CtdlPutUser(&masterCC.user);
 243                 CtdlGetUser(&masterCC.user, "SYS_Citadel");     // Just to be safe
 244         }
 245
 246         // Bind the server to a Unix-domain socket (user client access)
 247         CtdlRegisterServiceHook(0,
 248                                 file_citadel_socket,
 249                                 citproto_begin_session,
 250                                 do_command_loop,
 251                                 do_async_loop,
 252                                 CitadelServiceUDS);
 253
 254         // Bind the server to a Unix-domain socket (admin client access)
 255         CtdlRegisterServiceHook(0,
 256                                 file_citadel_admin_socket,
 257                                 citproto_begin_admin_session,
 258                                 do_command_loop,
 259                                 do_async_loop,
 260                                 CitadelServiceUDS);
 261         chmod(file_citadel_admin_socket, S_IRWXU);              // protect the admin socket - it offers high privilege
 262
 263         // Bind the server to our favorite TCP port (usually 504).
 264         CtdlRegisterServiceHook(CtdlGetConfigInt("c_port_number"),
 265                                 NULL,
 266                                 citproto_begin_session,
 267                                 do_command_loop,
 268                                 do_async_loop,
 269                                 CitadelServiceTCP);
 270
 271         // Load any server-side extensions available here.
 272         syslog(LOG_INFO, "main: initializing server extensions");
 273         initialize_modules(0);
 274
 275         // If we need host auth, start our chkpwd daemon.
 276         if (CtdlGetConfigInt("c_auth_mode") == AUTHMODE_HOST) {
 277                 start_chkpwd_daemon();
 278         }
 279
 280         // check, whether we're fired up another time after a crash.
 281         // if, post an aide message, so the admin has a chance to react.
 282         checkcrash();
 283
 284         // Now that we've bound the sockets, change to the Citadel user id and its corresponding group ids
 285         if (drop_root_perms) {
 286                 cdb_chmod_data();       // make sure we own our data files
 287                 getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf), &pwp);
 288                 if (pwp == NULL) {
 289                         syslog(LOG_ERR, "main: WARNING, getpwuid(%ld): %m Group IDs will be incorrect.", (long)ctdluid);
 290                 }
 291                 else {
 292                         initgroups(pw.pw_name, pw.pw_gid);
 293                         if (setgid(pw.pw_gid)) {
 294                                 syslog(LOG_ERR, "main: setgid(%ld): %m", (long)pw.pw_gid);
 295                         }
 296                 }
 297                 syslog(LOG_INFO, "main: changing uid to %ld", (long)ctdluid);
 298                 if (setuid(ctdluid) != 0) {
 299                         syslog(LOG_ERR, "main: setuid() failed: %m");
 300                 }
 301 #if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_DUMPABLE)
 302                 prctl(PR_SET_DUMPABLE, 1);
 303 #endif
 304         }
 305
 306         // We want to check for idle sessions once per minute
 307         CtdlRegisterSessionHook(terminate_idle_sessions, EVT_TIMER, PRIO_CLEANUP + 1);
 308
 309         // Are we in the undocumented rescue mode?
 310         if (rescue_string) {
 311                 undocumented_rescue_mode(rescue_string);
 312         }
 313         else {
 314                 // Go into multithreaded mode.  When this call exits, the server is stopping.
 315                 go_threading();
 316         }
 317
 318         // Get ready to shut down the server.
 319         master_cleanup(exit_signal);
 320 }