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