citadel/server_main.c

   1 /*
   2  * citserver's main() function lives here.
   3  *
   4  * Copyright (c) 1987-2021 by the citadel.org team
   5  *
   6  * This program is open source software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 3.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <stdio.h>
  17 #include <sys/types.h>
  18 #include <sys/stat.h>
  19 #include <grp.h>
  20 #include <sys/file.h>
  21 #include <libcitadel.h>
  22 #include "citserver.h"
  23 #include "svn_revision.h"
  24 #include "modules_init.h"
  25 #include "config.h"
  26 #include "control.h"
  27 #include "serv_extensions.h"
  28 #include "citadel_dirs.h"
  29 #include "user_ops.h"
  30
  31 uid_t ctdluid = 0;
  32 const char *CitadelServiceUDS="citadel-UDS";
  33 const char *CitadelServiceTCP="citadel-TCP";
  34 int sanity_diag_mode = 0;
  35
  36
  37 /*
  38  * Create or remove a lock file, so we only have one Citadel Server running at a time.
  39  * Set 'op' to nonzero to lock, zero to unlock.
  40  */
  41 void ctdl_lockfile(int op) {
  42         static char lockfilename[PATH_MAX];
  43         static FILE *fp;
  44
  45         if (op) {
  46                 syslog(LOG_DEBUG, "main: creating lockfile");
  47                 snprintf(lockfilename, sizeof lockfilename, "%s/citadel.lock", ctdl_run_dir);
  48                 fp = fopen(lockfilename, "w");
  49                 if (!fp) {
  50                         syslog(LOG_ERR, "%s: %m", lockfilename);
  51                         exit(CTDLEXIT_DB);
  52                 }
  53                 if (flock(fileno(fp), (LOCK_EX|LOCK_NB)) != 0) {
  54                         syslog(LOG_ERR, "main: cannot lock %s , is another citserver running?", lockfilename);
  55                         exit(CTDLEXIT_DB);
  56                 }
  57                 return;
  58         }
  59
  60         syslog(LOG_DEBUG, "main: removing lockfile");
  61         unlink(lockfilename);
  62         flock(fileno(fp), LOCK_UN);
  63         fclose(fp);
  64 }
  65
  66
  67 /*
  68  * Here's where it all begins.
  69  */
  70 int main(int argc, char **argv) {
  71
  72         char facility[32];
  73         int a;                  /* General-purpose variables */
  74         struct passwd pw, *pwp = NULL;
  75         char pwbuf[SIZ];
  76         int drop_root_perms = 1;
  77         int max_log_level = LOG_INFO;
  78         char *ctdldir = CTDLDIR;
  79         int syslog_facility = LOG_DAEMON;
  80         uid_t u = 0;
  81         struct passwd *p = NULL;
  82 #ifdef HAVE_RUN_DIR
  83         struct stat filestats;
  84 #endif
  85
  86         /* Tell 'em who's in da house */
  87         syslog(LOG_INFO, " ");
  88         syslog(LOG_INFO, " ");
  89         syslog(LOG_INFO, "*** Citadel server engine ***\n");
  90         syslog(LOG_INFO, "Version %d (build %s) ***", REV_LEVEL, svn_revision());
  91         syslog(LOG_INFO, "Copyright (C) 1987-2021 by the Citadel development team.");
  92         syslog(LOG_INFO, " ");
  93         syslog(LOG_INFO, "This program is open source software: you can redistribute it and/or");
  94         syslog(LOG_INFO, "modify it under the terms of the GNU General Public License, version 3.");
  95         syslog(LOG_INFO, " ");
  96         syslog(LOG_INFO, "This program is distributed in the hope that it will be useful,");
  97         syslog(LOG_INFO, "but WITHOUT ANY WARRANTY; without even the implied warranty of");
  98         syslog(LOG_INFO, "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the");
  99         syslog(LOG_INFO, "GNU General Public License for more details.");
 100         syslog(LOG_INFO, " ");
 101         syslog(LOG_INFO, "%s", libcitadel_version_string());
 102
 103         /* parse command-line arguments */
 104         while ((a=getopt(argc, argv, "cl:dh:x:t:B:Dru:s:")) != EOF) switch(a) {
 105
 106                 // test this binary for compatibility and exit
 107                 case 'c':
 108                         fprintf(stderr, "%s: binary compatibility confirmed\n", argv[0]);
 109                         exit(0);
 110                         break;
 111
 112                 // identify the desired syslog facility
 113                 case 'l':
 114                         safestrncpy(facility, optarg, sizeof(facility));
 115                         syslog_facility = SyslogFacility(facility);
 116                         break;
 117
 118                 // run in the background if -d was specified
 119                 case 'd':
 120                         running_as_daemon = 1;
 121                         break;
 122
 123                 // specify the data directory
 124                 case 'h':
 125                         ctdldir = optarg;
 126                         break;
 127
 128                 // identify the desired logging severity level
 129                 case 'x':
 130                         max_log_level = atoi(optarg);
 131                         break;
 132
 133                 // deprecated
 134                 case 't':
 135                         break;
 136
 137                 // deprecated
 138                 case 'B':
 139                         break;
 140
 141                 // deprecated
 142                 case 'D':
 143                         break;
 144
 145                 // -r tells the server not to drop root permissions.
 146                 // Don't use this unless you know what you're doing.
 147                 case 'r':
 148                         drop_root_perms = 0;
 149                         break;
 150
 151                 // -u tells the server what uid to run under...
 152                 case 'u':
 153                         u = atoi(optarg);
 154                         if (u > 0) {
 155                                 ctdluid = u;
 156                         }
 157                         else {
 158                                 p = getpwnam(optarg);
 159                                 if (p) {
 160                                         u = p->pw_uid;
 161                                 }
 162                         }
 163                         if (u > 0) {
 164                                 ctdluid = u;
 165                         }
 166                         break;
 167
 168                 // -s tells the server to behave differently during sanity checks
 169                 case 's':
 170                         sanity_diag_mode = atoi(optarg);
 171                         break;
 172
 173                 // any other parameter makes it crash and burn
 174                 default:
 175                         fprintf(stderr, "citserver: usage: "
 176                                         "citserver "
 177                                         "[-l LogFacility] "
 178                                         "[-x MaxLogLevel] "
 179                                         "[-d] [-r] "
 180                                         "[-u user] "
 181                                         "[-h HomeDir]\n"
 182                         );
 183                         exit(1);
 184         }
 185
 186         if (chdir(ctdldir) != 0) {
 187                 syslog(LOG_ERR, "main: unable to change directory to [%s]: %m", ctdldir);
 188                 exit(CTDLEXIT_HOME);
 189         }
 190         else {
 191                 syslog(LOG_INFO, "main: running in data directory %s", ctdldir);
 192         }
 193
 194         if ((ctdluid == 0) && (drop_root_perms == 0)) {
 195                 fprintf(stderr, "citserver: cannot determine user to run as; please specify -r or -u options\n");
 196                 exit(CTDLEXIT_UNUSER);
 197         }
 198
 199         /* Last ditch effort to determine the user name ... if there's a user called "citadel" then use that */
 200         if (ctdluid == 0) {
 201                 p = getpwnam("citadel");
 202                 if (!p) {
 203                         p = getpwnam("bbs");
 204                 }
 205                 if (!p) {
 206                         p = getpwnam("guest");
 207                 }
 208                 if (p) {
 209                         u = p->pw_uid;
 210                 }
 211                 if (u > 0) {
 212                         ctdluid = u;
 213                 }
 214         }
 215
 216         /* initialize the master context */
 217         InitializeMasterCC();
 218         InitializeMasterTSD();
 219
 220         setlogmask(LOG_UPTO(max_log_level));
 221         openlog("citserver",
 222                 ( running_as_daemon ? (LOG_PID) : (LOG_PID | LOG_PERROR) ),
 223                 syslog_facility
 224         );
 225
 226         /* daemonize, if we were asked to */
 227         if (running_as_daemon) {
 228                 start_daemon(0);
 229                 drop_root_perms = 1;
 230         }
 231
 232         if ((mkdir(ctdl_run_dir, 0755) != 0) && (errno != EEXIST)) {
 233                 syslog(LOG_ERR, "main: unable to create run directory [%s]: %m", ctdl_run_dir);
 234         }
 235
 236         if (chown(ctdl_run_dir, ctdluid, (pwp==NULL)?-1:pw.pw_gid) != 0) {
 237                 syslog(LOG_ERR, "main: unable to set the access rights for [%s]: %m", ctdl_run_dir);
 238         }
 239
 240         ctdl_lockfile(1);
 241         init_sysdep();                                          // Initialize...
 242         master_startup();                                       // Do non system dependent startup functions
 243         check_control();                                        // Check/sanitize/initialize control record, fix user indexes
 244         syslog(LOG_INFO, "main: upgrading modules");            // Run any upgrade entry points
 245         upgrade_modules();
 246
 247         /*
 248          * Load the user for the masterCC or create them if they don't exist
 249          */
 250         if (CtdlGetUser(&masterCC.user, "SYS_Citadel")) {
 251                 /* User doesn't exist. We can't use create user here as the user number needs to be 0 */
 252                 strcpy (masterCC.user.fullname, "SYS_Citadel") ;
 253                 CtdlPutUser(&masterCC.user);
 254                 CtdlGetUser(&masterCC.user, "SYS_Citadel");     /* Just to be safe */
 255         }
 256
 257         /*
 258          * Bind the server to a Unix-domain socket (user client access)
 259          */
 260         CtdlRegisterServiceHook(0,
 261                                 file_citadel_socket,
 262                                 citproto_begin_session,
 263                                 do_command_loop,
 264                                 do_async_loop,
 265                                 CitadelServiceUDS);
 266
 267         /*
 268          * Bind the server to a Unix-domain socket (admin client access)
 269          */
 270         CtdlRegisterServiceHook(0,
 271                                 file_citadel_admin_socket,
 272                                 citproto_begin_admin_session,
 273                                 do_command_loop,
 274                                 do_async_loop,
 275                                 CitadelServiceUDS);
 276         chmod(file_citadel_admin_socket, S_IRWXU);      /* for your eyes only */
 277
 278         /*
 279          * Bind the server to our favorite TCP port (usually 504).
 280          */
 281         CtdlRegisterServiceHook(CtdlGetConfigInt("c_port_number"),
 282                                 NULL,
 283                                 citproto_begin_session,
 284                                 do_command_loop,
 285                                 do_async_loop,
 286                                 CitadelServiceTCP);
 287
 288         /*
 289          * Load any server-side extensions available here.
 290          */
 291         syslog(LOG_INFO, "main: initializing server extensions");
 292         initialise_modules(0);
 293
 294         /*
 295          * If we need host auth, start our chkpwd daemon.
 296          */
 297         if (CtdlGetConfigInt("c_auth_mode") == AUTHMODE_HOST) {
 298                 start_chkpwd_daemon();
 299         }
 300
 301         /*
 302          * check, whether we're fired up another time after a crash.
 303          * if, post an aide message, so the admin has a chance to react.
 304          */
 305         checkcrash();
 306
 307         /*
 308          * Now that we've bound the sockets, change to the Citadel user id and its corresponding group ids
 309          */
 310         if (drop_root_perms) {
 311                 cdb_chmod_data();       /* make sure we own our data files */
 312                 getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf), &pwp);
 313                 if (pwp == NULL)
 314                         syslog(LOG_ERR, "main: WARNING, getpwuid(%ld): %m Group IDs will be incorrect.", (long)CTDLUID);
 315                 else {
 316                         initgroups(pw.pw_name, pw.pw_gid);
 317                         if (setgid(pw.pw_gid)) {
 318                                 syslog(LOG_ERR, "main: setgid(%ld): %m", (long)pw.pw_gid);
 319                         }
 320                 }
 321                 syslog(LOG_INFO, "main: changing uid to %ld", (long)CTDLUID);
 322                 if (setuid(CTDLUID) != 0) {
 323                         syslog(LOG_ERR, "main: setuid() failed: %m");
 324                 }
 325 #if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_DUMPABLE)
 326                 prctl(PR_SET_DUMPABLE, 1);
 327 #endif
 328         }
 329
 330         /* We want to check for idle sessions once per minute */
 331         CtdlRegisterSessionHook(terminate_idle_sessions, EVT_TIMER, PRIO_CLEANUP + 1);
 332
 333         /* Go into multithreaded mode.  When this call exits, the server is stopping. */
 334         go_threading();
 335
 336         /* Get ready to shut down the server. */
 337         int exit_code = master_cleanup(exit_signal);
 338         ctdl_lockfile(0);
 339         if (restart_server) {
 340                 syslog(LOG_INFO, "main: *** CITADEL SERVER IS RESTARTING ***");
 341                 execv(argv[0], argv);
 342         }
 343         return(exit_code);
 344 }