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