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