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