release/src/router/nfs-utils/utils/gssd/gssd_main_loop.c

   1 /*
   2   Copyright (c) 2004 The Regents of the University of Michigan.
   3   All rights reserved.
   4
   5   Redistribution and use in source and binary forms, with or without
   6   modification, are permitted provided that the following conditions
   7   are met:
   8
   9   1. Redistributions of source code must retain the above copyright
  10      notice, this list of conditions and the following disclaimer.
  11   2. Redistributions in binary form must reproduce the above copyright
  12      notice, this list of conditions and the following disclaimer in the
  13      documentation and/or other materials provided with the distribution.
  14   3. Neither the name of the University nor the names of its
  15      contributors may be used to endorse or promote products derived
  16      from this software without specific prior written permission.
  17
  18   THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  19   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  20   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21   DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  25   BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  26   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  27   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  28   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29 */
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include <config.h>
  33 #endif  /* HAVE_CONFIG_H */
  34
  35 #ifndef _GNU_SOURCE
  36 #define _GNU_SOURCE
  37 #endif
  38
  39 #include <sys/param.h>
  40 #include <sys/socket.h>
  41 #include <sys/poll.h>
  42 #include <netinet/in.h>
  43
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <memory.h>
  48 #include <errno.h>
  49 #include <fcntl.h>
  50 #include <signal.h>
  51 #include <unistd.h>
  52
  53 #include "gssd.h"
  54 #include "err_util.h"
  55
  56 extern struct pollfd *pollarray;
  57 extern int pollsize;
  58
  59 #define POLL_MILLISECS  500
  60
  61 static volatile int dir_changed = 1;
  62
  63 static void dir_notify_handler(int sig, siginfo_t *si, void *data)
  64 {
  65         dir_changed = 1;
  66 }
  67
  68 static void
  69 scan_poll_results(int ret)
  70 {
  71         int                     i;
  72         struct clnt_info        *clp;
  73
  74         for (clp = clnt_list.tqh_first; clp != NULL; clp = clp->list.tqe_next)
  75         {
  76                 i = clp->krb5_poll_index;
  77                 if (i >= 0 && pollarray[i].revents) {
  78                         if (pollarray[i].revents & POLLHUP)
  79                                 dir_changed = 1;
  80                         if (pollarray[i].revents & POLLIN)
  81                                 handle_krb5_upcall(clp);
  82                         pollarray[clp->krb5_poll_index].revents = 0;
  83                         ret--;
  84                         if (!ret)
  85                                 break;
  86                 }
  87                 i = clp->spkm3_poll_index;
  88                 if (i >= 0 && pollarray[i].revents) {
  89                         if (pollarray[i].revents & POLLHUP)
  90                                 dir_changed = 1;
  91                         if (pollarray[i].revents & POLLIN)
  92                                 handle_spkm3_upcall(clp);
  93                         pollarray[clp->spkm3_poll_index].revents = 0;
  94                         ret--;
  95                         if (!ret)
  96                                 break;
  97                 }
  98         }
  99 };
 100
 101 void
 102 gssd_run()
 103 {
 104         int                     ret;
 105         struct sigaction        dn_act;
 106         int                     fd;
 107         sigset_t                set;
 108
 109         /* Taken from linux/Documentation/dnotify.txt: */
 110         dn_act.sa_sigaction = dir_notify_handler;
 111         sigemptyset(&dn_act.sa_mask);
 112         dn_act.sa_flags = SA_SIGINFO;
 113         sigaction(DNOTIFY_SIGNAL, &dn_act, NULL);
 114
 115         /* just in case the signal is blocked... */
 116         sigemptyset(&set);
 117         sigaddset(&set, DNOTIFY_SIGNAL);
 118         sigprocmask(SIG_UNBLOCK, &set, NULL);
 119
 120         if ((fd = open(pipefs_nfsdir, O_RDONLY)) == -1) {
 121                 printerr(0, "ERROR: failed to open %s: %s\n",
 122                          pipefs_nfsdir, strerror(errno));
 123                 exit(1);
 124         }
 125         fcntl(fd, F_SETSIG, DNOTIFY_SIGNAL);
 126         fcntl(fd, F_NOTIFY, DN_CREATE|DN_DELETE|DN_MODIFY|DN_MULTISHOT);
 127
 128         init_client_list();
 129
 130         printerr(1, "beginning poll\n");
 131         while (1) {
 132                 while (dir_changed) {
 133                         dir_changed = 0;
 134                         if (update_client_list()) {
 135                                 printerr(0, "ERROR: couldn't update "
 136                                          "client list\n");
 137                                 exit(1);
 138                         }
 139                 }
 140                 /* race condition here: dir_changed could be set before we
 141                  * enter the poll, and we'd never notice if it weren't for the
 142                  * timeout. */
 143                 ret = poll(pollarray, pollsize, POLL_MILLISECS);
 144                 if (ret < 0) {
 145                         if (errno != EINTR)
 146                                 printerr(0,
 147                                          "WARNING: error return from poll\n");
 148                 } else if (ret == 0) {
 149                         /* timeout */
 150                 } else { /* ret > 0 */
 151                         scan_poll_results(ret);
 152                 }
 153         }
 154         close(fd);
 155         return;
 156 }