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

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