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 'v':
 131             message_level|=M_INFO|M_NOTICE|M_WARNING|M_ERR|M_SECURITY|
 132                 M_FATAL;
 133             break;
 134
 135         case 'w':
 136             message_level&=(~M_WARNING);
 137             break;
 138
 139         case 'd':
 140             message_level|=M_DEBUG_CONFIG|M_DEBUG_PHASE|M_DEBUG;
 141             break;
 142
 143         case 'f':
 144             message_level=M_FATAL;
 145             break;
 146
 147         case 'n':
 148             background=False;
 149             break;
 150
 151         case 'm':
 152             secnet_is_daemon=True;
 153             break;
 154
 155         case 'c':
 156             if (optarg)
 157                 configfile=safe_strdup(optarg,"config_filename");
 158             else
 159                 fatal("secnet: no config filename specified");
 160             break;
 161
 162         case 'j':
 163             just_check_config=True;
 164             break;
 165
 166         case 's':
 167             if (optarg)
 168                 sites_key=safe_strdup(optarg,"sites-key");
 169             else
 170                 fatal("secnet: no sites key specified");
 171             break;
 172
 173         case '?':
 174             exit(1);
 175             break;
 176
 177         default:
 178             Message(M_ERR,"secnet: Unknown getopt code %c\n",c);
 179         }
 180     }
 181
 182     if (argc-optind != 0) {
 183         Message(M_ERR,"secnet: You gave extra command line parameters, "
 184                 "which were ignored.\n");
 185     }
 186 }
 187
 188 static void setup(dict_t *config)
 189 {
 190     list_t *l;
 191     item_t *site;
 192     dict_t *system;
 193     struct passwd *pw;
 194     struct cloc loc;
 195     int i;
 196
 197     l=dict_lookup(config,"system");
 198
 199     if (!l || list_elem(l,0)->type!=t_dict) {
 200         fatal("configuration does not include a \"system\" dictionary");
 201     }
 202     system=list_elem(l,0)->data.dict;
 203     loc=list_elem(l,0)->loc;
 204
 205     /* Arrange systemwide log facility */
 206     l=dict_lookup(system,"log");
 207     if (!l) {
 208         fatal("configuration does not include a system/log facility");
 209     }
 210     system_log=init_log(l);
 211
 212     /* Who are we supposed to run as? */
 213     userid=dict_read_string(system,"userid",False,"system",loc);
 214     if (userid) {
 215         if (!(pw=getpwnam(userid)))
 216             fatal("userid \"%s\" not found",userid);
 217         uid=pw->pw_uid;
 218         gid=pw->pw_gid;
 219     }
 220
 221     /* Pidfile name */
 222     pidfile=dict_read_string(system,"pidfile",False,"system",loc);
 223
 224     /* Check whether we need root privileges */
 225     if (require_root_privileges && uid!=0) {
 226         fatal("the configured feature \"%s\" requires "
 227               "that secnet retain root privileges while running.",
 228               require_root_privileges_explanation);
 229     }
 230
 231     /* Go along site list, starting sites */
 232     l=dict_lookup(config,sites_key);
 233     if (!l) {
 234         Message(M_WARNING,"secnet: configuration key \"%s\" is missing; no "
 235                 "remote sites are defined\n",sites_key);
 236     } else {
 237         i=0;
 238         while ((site=list_elem(l, i++))) {
 239             struct site_if *s;
 240             if (site->type!=t_closure) {
 241                 cfgfatal(site->loc,"system","non-closure in site list");
 242             }
 243             if (site->data.closure->type!=CL_SITE) {
 244                 cfgfatal(site->loc,"system","non-site closure in site list");
 245             }
 246             s=site->data.closure->interface;
 247             s->control(s->st,True);
 248         }
 249     }
 250 }
 251
 252 struct poll_interest *register_for_poll(void *st, beforepoll_fn *before,
 253                        afterpoll_fn *after, cstring_t desc)
 254 {
 255     struct poll_interest *i;
 256
 257     NEW(i);
 258     i->before=before;
 259     i->after=after;
 260     i->state=st;
 261     i->nfds=0;
 262     i->desc=desc;
 263     LIST_INSERT_HEAD(&reg, i, entry);
 264     return i;
 265 }
 266
 267 void deregister_for_poll(struct poll_interest *i)
 268 {
 269     /* We cannot simply throw this away because we're reentrantly
 270      * inside the main loop, which needs to remember which range of
 271      * fds corresponds to this now-obsolete interest */
 272     i->before=0;
 273 }
 274
 275 static void system_phase_hook(void *sst, uint32_t newphase)
 276 {
 277     if (newphase==PHASE_SHUTDOWN && pidfile) {
 278         /* Try to unlink the pidfile; don't care if it fails */
 279         unlink(pidfile);
 280     }
 281 }
 282
 283 #if USE_SELECT
 284 static int fakepoll(struct pollfd *fds, int nfds, int timeout) {
 285     fd_set infds[1], outfds[1];
 286     int maxfd = -1, i, rc;
 287     struct timeval tvtimeout;
 288     FD_ZERO(infds);
 289     FD_ZERO(outfds);
 290     for(i = 0; i < nfds; ++i) {
 291         if(fds[i].events & POLLIN)
 292             FD_SET(fds[i].fd, infds);
 293         if(fds[i].events & POLLOUT)
 294             FD_SET(fds[i].fd, outfds);
 295         if(fds[i].fd > maxfd)
 296             maxfd = fds[i].fd;
 297     }
 298     if(timeout != -1) {
 299         tvtimeout.tv_sec = timeout / 1000;
 300         tvtimeout.tv_usec = 1000 * (timeout % 1000);
 301     }
 302     rc = select(maxfd + 1, infds, outfds, NULL,
 303                 timeout == -1 ? NULL : &tvtimeout);
 304     if(rc >= 0) {
 305         for(i = 0; i < nfds; ++i) {
 306             int revents = 0;
 307             if(FD_ISSET(fds[i].fd, infds))
 308                 revents |= POLLIN;
 309             if(FD_ISSET(fds[i].fd, outfds))
 310                 revents |= POLLOUT;
 311             fds[i].revents = revents;
 312         }
 313     }
 314     return rc;
 315 }
 316 #endif
 317
 318 struct timeval tv_now_global;
 319 uint64_t now_global;
 320
 321 static void run(void)
 322 {
 323     struct poll_interest *i, *itmp;
 324     int rv, nfds, idx;
 325     int timeout;
 326     struct pollfd *fds=0;
 327     int allocdfds=0, shortfall=0;
 328
 329     Message(M_NOTICE,"%s [%d]: starting\n",version,secnet_pid);
 330
 331     do {
 332         if (gettimeofday(&tv_now_global, NULL)!=0) {
 333             fatal_perror("main loop: gettimeofday");
 334         }
 335         now_global=((uint64_t)tv_now_global.tv_sec*(uint64_t)1000)+
 336                    ((uint64_t)tv_now_global.tv_usec/(uint64_t)1000);
 337         idx=0;
 338         LIST_FOREACH(i, &reg, entry) {
 339             int check;
 340             if (interest_isregistered(i)) {
 341                 for (check=0; check<i->nfds; check++) {
 342                     if(fds[idx+check].revents & POLLNVAL) {
 343                         fatal("run: poll (%s#%d) set POLLNVAL", i->desc, check);
 344                     }
 345                 }
 346                 i->after(i->state, fds+idx, i->nfds);
 347             }
 348             idx+=i->nfds;
 349         }
 350         if (shortfall) {
 351             allocdfds *= 2;
 352             allocdfds += shortfall;
 353             REALLOC_ARY(fds,allocdfds);
 354         }
 355         shortfall=0;
 356         idx=0;
 357         timeout=-1;
 358         LIST_FOREACH_SAFE(i, &reg, entry, itmp) {
 359             int remain=allocdfds-idx;
 360             nfds=remain;
 361             if (interest_isregistered(i)) {
 362                 rv=i->before(i->state, fds+idx, &nfds, &timeout);
 363                 if (rv!=0) {
 364                     if (rv!=ERANGE)
 365                         fatal("run: beforepoll_fn (%s) returns %d",i->desc,rv);
 366                     assert(nfds < INT_MAX/4 - shortfall);
 367                     shortfall += nfds-remain;
 368                     nfds=0;
 369                     timeout=0;
 370                 }
 371             } else {
 372                 nfds=0;
 373             }
 374             if (timeout<-1) {
 375                 fatal("run: beforepoll_fn (%s) set timeout to %d",
 376                       i->desc,timeout);
 377             }
 378             if (!interest_isregistered(i)) {
 379                 /* check this here, rather than earlier, so that we
 380                    handle the case where i->before() calls deregister */
 381                 LIST_REMOVE(i, entry);
 382                 free(i);
 383                 continue;
 384             }
 385             idx+=nfds;
 386             i->nfds=nfds;
 387         }
 388         do {
 389             if (finished) break;
 390 #if USE_SELECT
 391             rv=fakepoll(fds, idx, timeout);
 392 #else
 393             rv=poll(fds, idx, timeout);
 394 #endif
 395             if (rv<0) {
 396                 if (errno!=EINTR) {
 397                     fatal_perror("run: poll");
 398                 }
 399             }
 400         } while (rv<0);
 401     } while (!finished);
 402     free(fds);
 403 }
 404
 405 bool_t will_droppriv(void)
 406 {
 407     assert(current_phase >= PHASE_SETUP);
 408     return !!uid;
 409 }
 410
 411 /* Surrender privileges, if necessary */
 412 static void droppriv(void)
 413 {
 414     if (userid) {
 415         if (setgid(gid)!=0)
 416             fatal_perror("can't set gid to %ld",(long)gid);
 417         if (initgroups(userid, gid) < 0)
 418             fatal_perror("initgroups");
 419         if (setuid(uid)!=0) {
 420             fatal_perror("can't set uid to \"%s\"",userid);
 421         }
 422         assert(getuid() == uid);
 423         assert(geteuid() == uid);
 424         assert(getgid() == gid);
 425         assert(getegid() == gid);
 426     }
 427 }
 428
 429 /* Become a daemon, if necessary */
 430 static void become_daemon(void)
 431 {
 432     FILE *pf=NULL;
 433     pid_t p;
 434     int errfds[2];
 435
 436     add_hook(PHASE_SHUTDOWN,system_phase_hook,NULL);
 437
 438     /* We only want to become a daemon if we are not one
 439      already */
 440     if (background && !secnet_is_daemon) {
 441         p=fork();
 442         if (p>0) {
 443             /* Parent process - just exit */
 444             _exit(0);
 445         } else if (p==0) {
 446             /* Child process - all done, just carry on */
 447             secnet_is_daemon=True;
 448             if (setsid() < 0)
 449                 fatal_perror("setsid");
 450         } else {
 451             /* Error */
 452             fatal_perror("cannot fork");
 453             exit(1);
 454         }
 455     }
 456     if (secnet_is_daemon) {
 457         /* stderr etc are redirected to the system/log facility */
 458         pipe_cloexec(errfds);
 459         if (dup2(errfds[1],0) < 0
 460             || dup2(errfds[1],1) < 0
 461             || dup2(errfds[1],2) < 0)
 462             fatal_perror("can't dup2 pipe");
 463         if (close(errfds[1]) < 0)
 464             fatal_perror("can't close redundant pipe endpoint");
 465         log_from_fd(errfds[0],"stderr",system_log);
 466     }
 467     secnet_pid=getpid();
 468
 469     /* Now we can write the pidfile */
 470     if (pidfile) {
 471         pf=fopen(pidfile,"w");
 472         if (!pf) {
 473             fatal_perror("cannot open pidfile \"%s\"",pidfile);
 474         }
 475         if (fprintf(pf,"%ld\n",(long)secnet_pid) < 0
 476             || fclose(pf) < 0)
 477             fatal_perror("cannot write to pidfile \"%s\"",pidfile);
 478     }
 479 }
 480
 481 static signal_notify_fn finish,ignore_hup;
 482 static void finish(void *st, int signum)
 483 {
 484     finished=True;
 485     Message(M_NOTICE,"%s [%d]: received %s\n",version,secnet_pid,(string_t)st);
 486 }
 487 static void ignore_hup(void *st, int signum)
 488 {
 489     Message(M_INFO,"%s [%d]: received SIGHUP\n",version,secnet_pid);
 490     return;
 491 }
 492
 493 int main(int argc, char **argv)
 494 {
 495     dict_t *config;
 496
 497     phase_hooks_init();
 498
 499     enter_phase(PHASE_GETOPTS);
 500     parse_options(argc,argv);
 501
 502     enter_phase(PHASE_READCONFIG);
 503     config=read_conffile(configfile);
 504
 505     enter_phase(PHASE_SETUP);
 506     setup(config);
 507
 508     if (just_check_config) {
 509         Message(M_INFO,"configuration file check complete\n");
 510         exit(0);
 511     }
 512
 513     enter_phase(PHASE_DAEMONIZE);
 514     become_daemon();
 515
 516     enter_phase(PHASE_GETRESOURCES);
 517     /* Appropriate phase hooks will have been run */
 518
 519     enter_phase(PHASE_DROPPRIV);
 520     droppriv();
 521
 522     start_signal_handling();
 523     request_signal_notification(SIGTERM,finish,safe_strdup("SIGTERM","run"));
 524     if (!background) request_signal_notification(SIGINT,finish,
 525                                                  safe_strdup("SIGINT","run"));
 526     request_signal_notification(SIGHUP,ignore_hup,NULL);
 527     enter_phase(PHASE_RUN);
 528     run();
 529
 530     enter_phase(PHASE_SHUTDOWN);
 531     Message(M_NOTICE,"%s [%d]: finished\n",version,secnet_pid);
 532
 533     return 0;
 534 }