mdw@git.distorted.org.uk Git - secnet/blob - secnet.c

   1 /*
   2  * This file is part of secnet.
   3  * See README for full list of copyright holders.
   4  *
   5  * secnet is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version d of the License, or
   8  * (at your option) any later version.
   9  *
  10  * secnet is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * version 3 along with secnet; if not, see
  17  * https://www.gnu.org/licenses/gpl.html.
  18  */
  19
  20 #include "secnet.h"
  21 #include <stdio.h>
  22 #include <assert.h>
  23 #include <limits.h>
  24 #include <string.h>
  25 #include <getopt.h>
  26 #include <errno.h>
  27 #include <unistd.h>
  28 #include <sys/socket.h>
  29 #include <arpa/inet.h>
  30 #include <pwd.h>
  31 #include <grp.h>
  32
  33 #include "util.h"
  34 #include "conffile.h"
  35 #include "process.h"
  36
  37 #if __APPLE__
  38 /* apple's poll() does not work on char devs */
  39 # define USE_SELECT 1
  40 #endif
  41
  42 /* XXX should be from autoconf */
  43 static const char *configfile="/etc/secnet/secnet.conf";
  44 static const char *sites_key="sites";
  45 bool_t just_check_config=False;
  46 static char *userid=NULL;
  47 static uid_t uid=0;
  48 static gid_t gid;
  49 bool_t background=True;
  50 static char *pidfile=NULL;
  51 bool_t require_root_privileges=False;
  52 cstring_t require_root_privileges_explanation=NULL;
  53
  54 static pid_t secnet_pid;
  55
  56 /* Structures dealing with poll() call */
  57 struct poll_interest {
  58     beforepoll_fn *before; /* 0 if deregistered and waiting to be deleted */
  59     afterpoll_fn *after;
  60     void *state;
  61     int32_t nfds;
  62     cstring_t desc;
  63     LIST_ENTRY(poll_interest) entry;
  64 };
  65 static LIST_HEAD(, poll_interest) reg = LIST_HEAD_INITIALIZER(&reg);
  66
  67 static bool_t interest_isregistered(const struct poll_interest *i)
  68 {
  69     return !!i->before;
  70 }
  71
  72 static bool_t finished=False;
  73
  74 /* Parse the command line options */
  75 static void parse_options(int argc, char **argv)
  76 {
  77     int c;
  78
  79     while (True) {
  80         int option_index = 0;
  81         static struct option long_options[] = {
  82             {"verbose", 0, 0, 'v'},
  83             {"nowarnings", 0, 0, 'w'},
  84             {"help", 0, 0, 2},
  85             {"version", 0, 0, 1},
  86             {"nodetach", 0, 0, 'n'},
  87             {"managed", 0, 0, 'm'},
  88             {"silent", 0, 0, 'f'},
  89             {"quiet", 0, 0, 'f'},
  90             {"debug", 0, 0, 'd'},
  91             {"config", 1, 0, 'c'},
  92             {"just-check-config", 0, 0, 'j'},
  93             {"sites-key", 1, 0, 's'},
  94             {0,0,0,0}
  95         };
  96
  97         c=getopt_long(argc, argv, "vwdnjc:ft:s:m",
  98                       long_options, &option_index);
  99         if (c==-1)
 100             break;
 101
 102         switch(c) {
 103         case 2:
 104             /* Help */
 105             printf("Usage: secnet [OPTION]...\n\n"
 106                    "  -f, --silent, --quiet   suppress error messages\n"
 107                    "  -w, --nowarnings        suppress warnings\n"
 108                    "  -v, --verbose           output extra diagnostics\n"
 109                    "  -c, --config=filename   specify a configuration file\n"
 110                    "  -j, --just-check-config stop after reading "
 111                    "configuration file\n"
 112                    "  -s, --sites-key=name    configuration key that "
 113                    "specifies active sites\n"
 114                    "  -n, --nodetach          do not run in background\n"
 115                    "  -m, --managed           running under a supervisor\n"
 116                    "  -d, --debug             output debug messages\n"
 117                    "      --help              display this help and exit\n"
 118                    "      --version           output version information "
 119                    "and exit\n"
 120                 );
 121             exit(0);
 122             break;
 123
 124         case 1:
 125             /* Version */
 126             printf("%s\n",version);
 127             exit(0);
 128             break;
 129
 130         case 'd':
 131             message_level|=M_DEBUG_CONFIG|M_DEBUG_PHASE|M_DEBUG;
 132             /* fall through */
 133         case 'v':
 134             message_level|=M_INFO|M_NOTICE|M_WARNING|M_ERR|M_SECURITY|
 135                 M_FATAL;
 136             break;
 137
 138         case 'w':
 139             message_level&=(~M_WARNING);
 140             break;
 141
 142         case 'f':
 143             message_level=M_FATAL;
 144             break;
 145
 146         case 'n':
 147             background=False;
 148             break;
 149
 150         case 'm':
 151             secnet_is_daemon=True;
 152             break;
 153
 154         case 'c':
 155             if (optarg)
 156                 configfile=safe_strdup(optarg,"config_filename");
 157             else
 158                 fatal("secnet: no config filename specified");
 159             break;
 160
 161         case 'j':
 162             just_check_config=True;
 163             break;
 164
 165         case 's':
 166             if (optarg)
 167                 sites_key=safe_strdup(optarg,"sites-key");
 168             else
 169                 fatal("secnet: no sites key specified");
 170             break;
 171
 172         case '?':
 173             exit(1);
 174             break;
 175
 176         default:
 177             Message(M_ERR,"secnet: Unknown getopt code %c\n",c);
 178         }
 179     }
 180
 181     if (argc-optind != 0) {
 182         Message(M_ERR,"secnet: You gave extra command line parameters, "
 183                 "which were ignored.\n");
 184     }
 185 }
 186
 187 static void setup(dict_t *config)
 188 {
 189     list_t *l;
 190     item_t *site;
 191     dict_t *system;
 192     struct passwd *pw;
 193     struct cloc loc;
 194     int i;
 195
 196     l=dict_lookup(config,"system");
 197
 198     if (!l || list_elem(l,0)->type!=t_dict) {
 199         fatal("configuration does not include a \"system\" dictionary");
 200     }
 201     system=list_elem(l,0)->data.dict;
 202     loc=list_elem(l,0)->loc;
 203
 204     /* Arrange systemwide log facility */
 205     l=dict_lookup(system,"log");
 206     if (!l) {
 207         fatal("configuration does not include a system/log facility");
 208     }
 209     system_log=init_log(l);
 210
 211     /* Who are we supposed to run as? */
 212     userid=dict_read_string(system,"userid",False,"system",loc);
 213     if (userid) {
 214         if (!(pw=getpwnam(userid)))
 215             fatal("userid \"%s\" not found",userid);
 216         uid=pw->pw_uid;
 217         gid=pw->pw_gid;
 218     }
 219
 220     /* Pidfile name */
 221     pidfile=dict_read_string(system,"pidfile",False,"system",loc);
 222
 223     /* Check whether we need root privileges */
 224     if (require_root_privileges && uid!=0) {
 225         fatal("the configured feature \"%s\" requires "
 226               "that secnet retain root privileges while running.",
 227               require_root_privileges_explanation);
 228     }
 229
 230     /* Go along site list, starting sites */
 231     l=dict_lookup(config,sites_key);
 232     if (!l) {
 233         Message(M_WARNING,"secnet: configuration key \"%s\" is missing; no "
 234                 "remote sites are defined\n",sites_key);
 235     } else {
 236         i=0;
 237         while ((site=list_elem(l, i++))) {
 238             struct site_if *s;
 239             if (site->type!=t_closure) {
 240                 cfgfatal(site->loc,"system","non-closure in site list");
 241             }
 242             if (site->data.closure->type!=CL_SITE) {
 243                 cfgfatal(site->loc,"system","non-site closure in site list");
 244             }
 245             s=site->data.closure->interface;
 246             s->control(s->st,True);
 247         }
 248     }
 249 }
 250
 251 struct poll_interest *register_for_poll(void *st, beforepoll_fn *before,
 252                        afterpoll_fn *after, cstring_t desc)
 253 {
 254     struct poll_interest *i;
 255
 256     NEW(i);
 257     i->before=before;
 258     i->after=after;
 259     i->state=st;
 260     i->nfds=0;
 261     i->desc=desc;
 262     LIST_INSERT_HEAD(&reg, i, entry);
 263     return i;
 264 }
 265
 266 void deregister_for_poll(struct poll_interest *i)
 267 {
 268     /* We cannot simply throw this away because we're reentrantly
 269      * inside the main loop, which needs to remember which range of
 270      * fds corresponds to this now-obsolete interest */
 271     i->before=0;
 272 }
 273
 274 static void system_phase_hook(void *sst, uint32_t newphase)
 275 {
 276     if (newphase==PHASE_SHUTDOWN && pidfile) {
 277         /* Try to unlink the pidfile; don't care if it fails */
 278         unlink(pidfile);
 279     }
 280 }
 281
 282 #if USE_SELECT
 283 static int fakepoll(struct pollfd *fds, int nfds, int timeout) {
 284     fd_set infds[1], outfds[1];
 285     int maxfd = -1, i, rc;
 286     struct timeval tvtimeout;
 287     FD_ZERO(infds);
 288     FD_ZERO(outfds);
 289     for(i = 0; i < nfds; ++i) {
 290         if(fds[i].events & POLLIN)
 291             FD_SET(fds[i].fd, infds);
 292         if(fds[i].events & POLLOUT)
 293             FD_SET(fds[i].fd, outfds);
 294         if(fds[i].fd > maxfd)
 295             maxfd = fds[i].fd;
 296     }
 297     if(timeout != -1) {
 298         tvtimeout.tv_sec = timeout / 1000;
 299         tvtimeout.tv_usec = 1000 * (timeout % 1000);
 300     }
 301     rc = select(maxfd + 1, infds, outfds, NULL,
 302                 timeout == -1 ? NULL : &tvtimeout);
 303     if(rc >= 0) {
 304         for(i = 0; i < nfds; ++i) {
 305             int revents = 0;
 306             if(FD_ISSET(fds[i].fd, infds))
 307                 revents |= POLLIN;
 308             if(FD_ISSET(fds[i].fd, outfds))
 309                 revents |= POLLOUT;
 310             fds[i].revents = revents;
 311         }
 312     }
 313     return rc;
 314 }
 315 #endif
 316
 317 struct timeval tv_now_global;
 318 uint64_t now_global;
 319
 320 static void run(void)
 321 {
 322     struct poll_interest *i, *itmp;
 323     int rv, nfds, idx;
 324     int timeout;
 325     struct pollfd *fds=0;
 326     int allocdfds=0, shortfall=0;
 327
 328     Message(M_NOTICE,"%s [%d]: starting\n",version,secnet_pid);
 329
 330     do {
 331         if (gettimeofday(&tv_now_global, NULL)!=0) {
 332             fatal_perror("main loop: gettimeofday");
 333         }
 334         now_global=((uint64_t)tv_now_global.tv_sec*(uint64_t)1000)+
 335                    ((uint64_t)tv_now_global.tv_usec/(uint64_t)1000);
 336         idx=0;
 337         LIST_FOREACH(i, &reg, entry) {
 338             int check;
 339             if (interest_isregistered(i)) {
 340                 for (check=0; check<i->nfds; check++) {
 341                     if(fds[idx+check].revents & POLLNVAL) {
 342                         fatal("run: poll (%s#%d) set POLLNVAL", i->desc, check);
 343                     }
 344                 }
 345                 i->after(i->state, fds+idx, i->nfds);
 346             }
 347             idx+=i->nfds;
 348         }
 349         if (shortfall) {
 350             allocdfds *= 2;
 351             allocdfds += shortfall;
 352             REALLOC_ARY(fds,allocdfds);
 353         }
 354         shortfall=0;
 355         idx=0;
 356         timeout=-1;
 357         LIST_FOREACH_SAFE(i, &reg, entry, itmp) {
 358             int remain=allocdfds-idx;
 359             nfds=remain;
 360             if (interest_isregistered(i)) {
 361                 rv=i->before(i->state, fds+idx, &nfds, &timeout);
 362                 if (rv!=0) {
 363                     if (rv!=ERANGE)
 364                         fatal("run: beforepoll_fn (%s) returns %d",i->desc,rv);
 365                     assert(nfds < INT_MAX/4 - shortfall);
 366                     shortfall += nfds-remain;
 367                     nfds=0;
 368                     timeout=0;
 369                 }
 370             } else {
 371                 nfds=0;
 372             }
 373             if (timeout<-1) {
 374                 fatal("run: beforepoll_fn (%s) set timeout to %d",
 375                       i->desc,timeout);
 376             }
 377             if (!interest_isregistered(i)) {
 378                 /* check this here, rather than earlier, so that we
 379                    handle the case where i->before() calls deregister */
 380                 LIST_REMOVE(i, entry);
 381                 free(i);
 382                 continue;
 383             }
 384             idx+=nfds;
 385             i->nfds=nfds;
 386         }
 387         do {
 388             if (finished) break;
 389 #if USE_SELECT
 390             rv=fakepoll(fds, idx, timeout);
 391 #else
 392             rv=poll(fds, idx, timeout);
 393 #endif
 394             if (rv<0) {
 395                 if (errno!=EINTR) {
 396                     fatal_perror("run: poll");
 397                 }
 398             }
 399         } while (rv<0);
 400     } while (!finished);
 401     free(fds);
 402 }
 403
 404 bool_t will_droppriv(void)
 405 {
 406     assert(current_phase >= PHASE_SETUP);
 407     return !!uid;
 408 }
 409
 410 /* Surrender privileges, if necessary */
 411 static void droppriv(void)
 412 {
 413     if (userid) {
 414         if (setgid(gid)!=0)
 415             fatal_perror("can't set gid to %ld",(long)gid);
 416         if (initgroups(userid, gid) < 0)
 417             fatal_perror("initgroups");
 418         if (setuid(uid)!=0) {
 419             fatal_perror("can't set uid to \"%s\"",userid);
 420         }
 421         assert(getuid() == uid);
 422         assert(geteuid() == uid);
 423         assert(getgid() == gid);
 424         assert(getegid() == gid);
 425     }
 426 }
 427
 428 /* Become a daemon, if necessary */
 429 static void become_daemon(void)
 430 {
 431     FILE *pf=NULL;
 432     pid_t p;
 433     int errfds[2];
 434
 435     add_hook(PHASE_SHUTDOWN,system_phase_hook,NULL);
 436
 437     /* We only want to become a daemon if we are not one
 438      already */
 439     if (background && !secnet_is_daemon) {
 440         p=fork();
 441         if (p>0) {
 442             /* Parent process - just exit */
 443             _exit(0);
 444         } else if (p==0) {
 445             /* Child process - all done, just carry on */
 446             secnet_is_daemon=True;
 447             if (setsid() < 0)
 448                 fatal_perror("setsid");
 449         } else {
 450             /* Error */
 451             fatal_perror("cannot fork");
 452             exit(1);
 453         }
 454     }
 455     if (secnet_is_daemon) {
 456         /* stderr etc are redirected to the system/log facility */
 457         pipe_cloexec(errfds);
 458         if (dup2(errfds[1],0) < 0
 459             || dup2(errfds[1],1) < 0
 460             || dup2(errfds[1],2) < 0)
 461             fatal_perror("can't dup2 pipe");
 462         if (close(errfds[1]) < 0)
 463             fatal_perror("can't close redundant pipe endpoint");
 464         log_from_fd(errfds[0],"stderr",system_log);
 465     }
 466     secnet_pid=getpid();
 467
 468     /* Now we can write the pidfile */
 469     if (pidfile) {
 470         pf=fopen(pidfile,"w");
 471         if (!pf) {
 472             fatal_perror("cannot open pidfile \"%s\"",pidfile);
 473         }
 474         if (fprintf(pf,"%ld\n",(long)secnet_pid) < 0
 475             || fclose(pf) < 0)
 476             fatal_perror("cannot write to pidfile \"%s\"",pidfile);
 477     }
 478 }
 479
 480 static signal_notify_fn finish,ignore_hup;
 481 static void finish(void *st, int signum)
 482 {
 483     finished=True;
 484     Message(M_NOTICE,"%s [%d]: received %s\n",version,secnet_pid,(string_t)st);
 485 }
 486 static void ignore_hup(void *st, int signum)
 487 {
 488     Message(M_INFO,"%s [%d]: received SIGHUP\n",version,secnet_pid);
 489     return;
 490 }
 491
 492 int main(int argc, char **argv)
 493 {
 494     dict_t *config;
 495
 496     phase_hooks_init();
 497
 498     enter_phase(PHASE_GETOPTS);
 499     parse_options(argc,argv);
 500
 501     enter_phase(PHASE_READCONFIG);
 502     config=read_conffile(configfile);
 503
 504     enter_phase(PHASE_SETUP);
 505     setup(config);
 506
 507     if (just_check_config) {
 508         Message(M_INFO,"configuration file check complete\n");
 509         exit(0);
 510     }
 511
 512     enter_phase(PHASE_DAEMONIZE);
 513     become_daemon();
 514
 515     enter_phase(PHASE_GETRESOURCES);
 516     /* Appropriate phase hooks will have been run */
 517
 518     enter_phase(PHASE_DROPPRIV);
 519     droppriv();
 520
 521     start_signal_handling();
 522     request_signal_notification(SIGTERM,finish,safe_strdup("SIGTERM","run"));
 523     if (!background) request_signal_notification(SIGINT,finish,
 524                                                  safe_strdup("SIGINT","run"));
 525     request_signal_notification(SIGHUP,ignore_hup,NULL);
 526     enter_phase(PHASE_RUN);
 527     run();
 528
 529     enter_phase(PHASE_SHUTDOWN);
 530     Message(M_NOTICE,"%s [%d]: finished\n",version,secnet_pid);
 531
 532     return 0;
 533 }