mdw@git.distorted.org.uk Git - secnet/blob - secnet.c

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