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", 0, 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             output debug messages\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             exit(1);
 145             break;
 146
 147         default:
 148             Message(M_ERR,"secnet: Unknown getopt code %c\n",c);
 149         }
 150     }
 151
 152     if (argc-optind != 0) {
 153         Message(M_ERR,"secnet: You gave extra command line parameters, "
 154                 "which were ignored.\n");
 155     }
 156 }
 157
 158 static void setup(dict_t *config)
 159 {
 160     list_t *l;
 161     item_t *site;
 162     dict_t *system;
 163     struct passwd *pw;
 164     struct cloc loc;
 165     int i;
 166
 167     l=dict_lookup(config,"system");
 168
 169     if (!l || list_elem(l,0)->type!=t_dict) {
 170         fatal("configuration does not include a \"system\" dictionary");
 171     }
 172     system=list_elem(l,0)->data.dict;
 173     loc=list_elem(l,0)->loc;
 174
 175     /* Arrange systemwide log facility */
 176     l=dict_lookup(system,"log");
 177     if (!l) {
 178         fatal("configuration does not include a system/log facility");
 179     }
 180     system_log=init_log(l);
 181
 182     /* Who are we supposed to run as? */
 183     userid=dict_read_string(system,"userid",False,"system",loc);
 184     if (userid) {
 185         do {
 186             pw=getpwent();
 187             if (pw && strcmp(pw->pw_name,userid)==0) {
 188                 uid=pw->pw_uid;
 189                 break;
 190             }
 191         } while(pw);
 192         endpwent();
 193         if (uid==0) {
 194             fatal("userid \"%s\" not found",userid);
 195         }
 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     assert(total_nfds < INT_MAX - max_nfds);
 242     total_nfds+=max_nfds;
 243     i->next=reg;
 244     reg=i;
 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         for (i=reg; i; i=i->next) {
 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         for (i=reg; i; i=i->next) {
 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",timeout);
 335             }
 336             idx+=nfds;
 337             remain-=nfds;
 338             i->nfds=nfds;
 339         }
 340         do {
 341             if (finished) break;
 342 #if USE_SELECT
 343             rv=fakepoll(fds, idx, timeout);
 344 #else
 345             rv=poll(fds, idx, timeout);
 346 #endif
 347             if (rv<0) {
 348                 if (errno!=EINTR) {
 349                     fatal_perror("run: poll");
 350                 }
 351             }
 352         } while (rv<0);
 353     } while (!finished);
 354     free(fds);
 355 }
 356
 357 static void droppriv(void)
 358 {
 359     FILE *pf=NULL;
 360     pid_t p;
 361     int errfds[2];
 362
 363     add_hook(PHASE_SHUTDOWN,system_phase_hook,NULL);
 364
 365     /* Open the pidfile for writing now: we may be unable to do so
 366        once we drop privileges. */
 367     if (pidfile) {
 368         pf=fopen(pidfile,"w");
 369         if (!pf) {
 370             fatal_perror("cannot open pidfile \"%s\"",pidfile);
 371         }
 372     }
 373     if (!background && pf) {
 374         fprintf(pf,"%d\n",getpid());
 375         fclose(pf);
 376     }
 377
 378     /* Now drop privileges */
 379     if (uid!=0) {
 380         if (setuid(uid)!=0) {
 381             fatal_perror("can't set uid to \"%s\"",userid);
 382         }
 383     }
 384     if (background) {
 385         p=fork();
 386         if (p>0) {
 387             if (pf) {
 388                 /* Parent process - write pidfile, exit */
 389                 fprintf(pf,"%d\n",p);
 390                 fclose(pf);
 391             }
 392             exit(0);
 393         } else if (p==0) {
 394             /* Child process - all done, just carry on */
 395             if (pf) fclose(pf);
 396             /* Close stdin and stdout; we don't need them any more.
 397                stderr is redirected to the system/log facility */
 398             if (pipe(errfds)!=0) {
 399                 fatal_perror("can't create pipe for stderr");
 400             }
 401             close(0);
 402             close(1);
 403             close(2);
 404             dup2(errfds[1],0);
 405             dup2(errfds[1],1);
 406             dup2(errfds[1],2);
 407             secnet_is_daemon=True;
 408             setsid();
 409             log_from_fd(errfds[0],"stderr",system_log);
 410         } else {
 411             /* Error */
 412             fatal_perror("cannot fork");
 413             exit(1);
 414         }
 415     }
 416     secnet_pid=getpid();
 417 }
 418
 419 static signal_notify_fn finish,ignore_hup;
 420 static void finish(void *st, int signum)
 421 {
 422     finished=True;
 423     Message(M_NOTICE,"%s [%d]: received %s\n",version,secnet_pid,(string_t)st);
 424 }
 425 static void ignore_hup(void *st, int signum)
 426 {
 427     Message(M_INFO,"%s [%d]: received SIGHUP\n",version,secnet_pid);
 428     return;
 429 }
 430
 431 int main(int argc, char **argv)
 432 {
 433     dict_t *config;
 434
 435     enter_phase(PHASE_GETOPTS);
 436     parse_options(argc,argv);
 437
 438     enter_phase(PHASE_READCONFIG);
 439     config=read_conffile(configfile);
 440
 441     enter_phase(PHASE_SETUP);
 442     setup(config);
 443
 444     if (just_check_config) {
 445         Message(M_INFO,"configuration file check complete\n");
 446         exit(0);
 447     }
 448
 449     enter_phase(PHASE_GETRESOURCES);
 450     /* Appropriate phase hooks will have been run */
 451
 452     enter_phase(PHASE_DROPPRIV);
 453     droppriv();
 454
 455     start_signal_handling();
 456     request_signal_notification(SIGTERM,finish,safe_strdup("SIGTERM","run"));
 457     if (!background) request_signal_notification(SIGINT,finish,
 458                                                  safe_strdup("SIGINT","run"));
 459     request_signal_notification(SIGHUP,ignore_hup,NULL);
 460     enter_phase(PHASE_RUN);
 461     run();
 462
 463     enter_phase(PHASE_SHUTDOWN);
 464     Message(M_NOTICE,"%s [%d]: finished\n",version,secnet_pid);
 465
 466     return 0;
 467 }