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     struct poll_interest *next;
  46 };
  47 static struct poll_interest *reg=NULL;
  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             {"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:",
  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                    "  -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 'c':
 128             if (optarg)
 129                 configfile=safe_strdup(optarg,"config_filename");
 130             else
 131                 fatal("secnet: no config filename specified");
 132             break;
 133
 134         case 'j':
 135             just_check_config=True;
 136             break;
 137
 138         case 's':
 139             if (optarg)
 140                 sites_key=safe_strdup(optarg,"sites-key");
 141             else
 142                 fatal("secnet: no sites key specified");
 143             break;
 144
 145         case '?':
 146             exit(1);
 147             break;
 148
 149         default:
 150             Message(M_ERR,"secnet: Unknown getopt code %c\n",c);
 151         }
 152     }
 153
 154     if (argc-optind != 0) {
 155         Message(M_ERR,"secnet: You gave extra command line parameters, "
 156                 "which were ignored.\n");
 157     }
 158 }
 159
 160 static void setup(dict_t *config)
 161 {
 162     list_t *l;
 163     item_t *site;
 164     dict_t *system;
 165     struct passwd *pw;
 166     struct cloc loc;
 167     int i;
 168
 169     l=dict_lookup(config,"system");
 170
 171     if (!l || list_elem(l,0)->type!=t_dict) {
 172         fatal("configuration does not include a \"system\" dictionary");
 173     }
 174     system=list_elem(l,0)->data.dict;
 175     loc=list_elem(l,0)->loc;
 176
 177     /* Arrange systemwide log facility */
 178     l=dict_lookup(system,"log");
 179     if (!l) {
 180         fatal("configuration does not include a system/log facility");
 181     }
 182     system_log=init_log(l);
 183
 184     /* Who are we supposed to run as? */
 185     userid=dict_read_string(system,"userid",False,"system",loc);
 186     if (userid) {
 187         if(!(pw=getpwnam(userid)))
 188             fatal("userid \"%s\" not found",userid);
 189         uid=pw->pw_uid;
 190         gid=pw->pw_gid;
 191     }
 192
 193     /* Pidfile name */
 194     pidfile=dict_read_string(system,"pidfile",False,"system",loc);
 195
 196     /* Check whether we need root privileges */
 197     if (require_root_privileges && uid!=0) {
 198         fatal("the configured feature \"%s\" requires "
 199               "that secnet retain root privileges while running.",
 200               require_root_privileges_explanation);
 201     }
 202
 203     /* Go along site list, starting sites */
 204     l=dict_lookup(config,sites_key);
 205     if (!l) {
 206         Message(M_WARNING,"secnet: configuration key \"%s\" is missing; no "
 207                 "remote sites are defined\n",sites_key);
 208     } else {
 209         i=0;
 210         while ((site=list_elem(l, i++))) {
 211             struct site_if *s;
 212             if (site->type!=t_closure) {
 213                 cfgfatal(site->loc,"system","non-closure in site list");
 214             }
 215             if (site->data.closure->type!=CL_SITE) {
 216                 cfgfatal(site->loc,"system","non-site closure in site list");
 217             }
 218             s=site->data.closure->interface;
 219             s->control(s->st,True);
 220         }
 221     }
 222 }
 223
 224 void register_for_poll(void *st, beforepoll_fn *before,
 225                        afterpoll_fn *after, int32_t max_nfds, cstring_t desc)
 226 {
 227     struct poll_interest *i;
 228
 229     i=safe_malloc(sizeof(*i),"register_for_poll");
 230     i->before=before;
 231     i->after=after;
 232     i->state=st;
 233     i->max_nfds=max_nfds;
 234     i->nfds=0;
 235     i->desc=desc;
 236     assert(total_nfds < INT_MAX - max_nfds);
 237     total_nfds+=max_nfds;
 238     i->next=reg;
 239     reg=i;
 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, remain, idx;
 293     int timeout;
 294     struct pollfd *fds;
 295
 296     fds=safe_malloc(sizeof(*fds)*total_nfds, "run");
 297
 298     Message(M_NOTICE,"%s [%d]: starting\n",version,secnet_pid);
 299
 300     do {
 301         if (gettimeofday(&tv_now_global, NULL)!=0) {
 302             fatal_perror("main loop: gettimeofday");
 303         }
 304         now_global=((uint64_t)tv_now_global.tv_sec*(uint64_t)1000)+
 305                    ((uint64_t)tv_now_global.tv_usec/(uint64_t)1000);
 306         idx=0;
 307         for (i=reg; i; i=i->next) {
 308             int check;
 309             for (check=0; check<i->nfds; check++) {
 310                 if(fds[idx+check].revents & POLLNVAL) {
 311                     fatal("run: poll (%s#%d) set POLLNVAL", i->desc, check);
 312                 }
 313             }
 314             i->after(i->state, fds+idx, i->nfds);
 315             idx+=i->nfds;
 316         }
 317         remain=total_nfds;
 318         idx=0;
 319         timeout=-1;
 320         for (i=reg; i; i=i->next) {
 321             nfds=remain;
 322             rv=i->before(i->state, fds+idx, &nfds, &timeout);
 323             if (rv!=0) {
 324                 /* XXX we need to handle this properly: increase the
 325                    nfds available */
 326                 fatal("run: beforepoll_fn (%s) returns %d",i->desc,rv);
 327             }
 328             if (timeout<-1) {
 329                 fatal("run: beforepoll_fn (%s) set timeout to %d",timeout);
 330             }
 331             idx+=nfds;
 332             remain-=nfds;
 333             i->nfds=nfds;
 334         }
 335         do {
 336             if (finished) break;
 337 #if USE_SELECT
 338             rv=fakepoll(fds, idx, timeout);
 339 #else
 340             rv=poll(fds, idx, timeout);
 341 #endif
 342             if (rv<0) {
 343                 if (errno!=EINTR) {
 344                     fatal_perror("run: poll");
 345                 }
 346             }
 347         } while (rv<0);
 348     } while (!finished);
 349     free(fds);
 350 }
 351
 352 static void droppriv(void)
 353 {
 354     FILE *pf=NULL;
 355     pid_t p;
 356     int errfds[2];
 357
 358     add_hook(PHASE_SHUTDOWN,system_phase_hook,NULL);
 359
 360     /* Open the pidfile for writing now: we may be unable to do so
 361        once we drop privileges. */
 362     if (pidfile) {
 363         pf=fopen(pidfile,"w");
 364         if (!pf) {
 365             fatal_perror("cannot open pidfile \"%s\"",pidfile);
 366         }
 367     }
 368     if (!background && pf) {
 369         fprintf(pf,"%d\n",getpid());
 370         fclose(pf);
 371     }
 372
 373     /* Now drop privileges */
 374     if (userid) {
 375         if (setgid(gid)!=0)
 376             fatal_perror("can't set gid to %ld",(long)gid);
 377         if(initgroups(userid, gid) < 0)
 378             fatal_perror("initgroups");
 379         if (setuid(uid)!=0) {
 380             fatal_perror("can't set uid to \"%s\"",userid);
 381         }
 382         assert(getuid() == uid);
 383         assert(geteuid() == uid);
 384         assert(getgid() == gid);
 385         assert(getegid() == gid);
 386     }
 387     if (background) {
 388         p=fork();
 389         if (p>0) {
 390             if (pf) {
 391                 /* Parent process - write pidfile, exit */
 392                 fprintf(pf,"%d\n",p);
 393                 fclose(pf);
 394             }
 395             exit(0);
 396         } else if (p==0) {
 397             /* Child process - all done, just carry on */
 398             if (pf) fclose(pf);
 399             /* Close stdin and stdout; we don't need them any more.
 400                stderr is redirected to the system/log facility */
 401             if (pipe(errfds)!=0) {
 402                 fatal_perror("can't create pipe for stderr");
 403             }
 404             close(0);
 405             close(1);
 406             close(2);
 407             dup2(errfds[1],0);
 408             dup2(errfds[1],1);
 409             dup2(errfds[1],2);
 410             secnet_is_daemon=True;
 411             setsid();
 412             log_from_fd(errfds[0],"stderr",system_log);
 413         } else {
 414             /* Error */
 415             fatal_perror("cannot fork");
 416             exit(1);
 417         }
 418     }
 419     secnet_pid=getpid();
 420 }
 421
 422 static signal_notify_fn finish,ignore_hup;
 423 static void finish(void *st, int signum)
 424 {
 425     finished=True;
 426     Message(M_NOTICE,"%s [%d]: received %s\n",version,secnet_pid,(string_t)st);
 427 }
 428 static void ignore_hup(void *st, int signum)
 429 {
 430     Message(M_INFO,"%s [%d]: received SIGHUP\n",version,secnet_pid);
 431     return;
 432 }
 433
 434 int main(int argc, char **argv)
 435 {
 436     dict_t *config;
 437
 438     enter_phase(PHASE_GETOPTS);
 439     parse_options(argc,argv);
 440
 441     enter_phase(PHASE_READCONFIG);
 442     config=read_conffile(configfile);
 443
 444     enter_phase(PHASE_SETUP);
 445     setup(config);
 446
 447     if (just_check_config) {
 448         Message(M_INFO,"configuration file check complete\n");
 449         exit(0);
 450     }
 451
 452     enter_phase(PHASE_GETRESOURCES);
 453     /* Appropriate phase hooks will have been run */
 454
 455     enter_phase(PHASE_DROPPRIV);
 456     droppriv();
 457
 458     start_signal_handling();
 459     request_signal_notification(SIGTERM,finish,safe_strdup("SIGTERM","run"));
 460     if (!background) request_signal_notification(SIGINT,finish,
 461                                                  safe_strdup("SIGINT","run"));
 462     request_signal_notification(SIGHUP,ignore_hup,NULL);
 463     enter_phase(PHASE_RUN);
 464     run();
 465
 466     enter_phase(PHASE_SHUTDOWN);
 467     Message(M_NOTICE,"%s [%d]: finished\n",version,secnet_pid);
 468
 469     return 0;
 470 }