lustre/utils/gss/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 #ifndef _GNU_SOURCE
  32 #define _GNU_SOURCE
  33 #endif
  34 #include <sys/param.h>
  35 #include <sys/socket.h>
  36 #include <sys/poll.h>
  37 #include <netinet/in.h>
  38
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <memory.h>
  43 #include <errno.h>
  44 #include <fcntl.h>
  45 #include <signal.h>
  46 #include <unistd.h>
  47
  48 #include "gssd.h"
  49 #include "err_util.h"
  50
  51 extern struct pollfd *pollarray;
  52 extern int pollsize;
  53
  54 #define POLL_MILLISECS  500
  55
  56 static volatile int dir_changed = 1;
  57
  58 static void dir_notify_handler(int sig, siginfo_t *si, void *data)
  59 {
  60         dir_changed = 1;
  61 }
  62
  63 static void
  64 scan_poll_results(int ret)
  65 {
  66         int                     i;
  67         struct clnt_info        *clp;
  68
  69         for (clp = clnt_list.tqh_first; clp != NULL; clp = clp->list.tqe_next)
  70         {
  71                 i = clp->krb5_poll_index;
  72                 if (i >= 0 && pollarray[i].revents) {
  73                         if (pollarray[i].revents & POLLHUP)
  74                                 dir_changed = 1;
  75                         if (pollarray[i].revents & POLLIN)
  76                                 handle_krb5_upcall(clp);
  77                         pollarray[clp->krb5_poll_index].revents = 0;
  78                         ret--;
  79                         if (!ret)
  80                                 break;
  81                 }
  82                 i = clp->spkm3_poll_index;
  83                 if (i >= 0 && pollarray[i].revents) {
  84                         if (pollarray[i].revents & POLLHUP)
  85                                 dir_changed = 1;
  86                         if (pollarray[i].revents & POLLIN)
  87                                 handle_spkm3_upcall(clp);
  88                         pollarray[clp->spkm3_poll_index].revents = 0;
  89                         ret--;
  90                         if (!ret)
  91                                 break;
  92                 }
  93         }
  94 };
  95
  96 void
  97 lgssd_run()
  98 {
  99         int                     ret;
 100         struct sigaction        dn_act;
 101         int                     fd;
 102         time_t                  child_check = 0;
 103         pid_t                   child_pid;
 104
 105         /* Taken from linux/Documentation/dnotify.txt: */
 106         dn_act.sa_sigaction = dir_notify_handler;
 107         sigemptyset(&dn_act.sa_mask);
 108         dn_act.sa_flags = SA_SIGINFO;
 109         sigaction(DNOTIFY_SIGNAL, &dn_act, NULL);
 110
 111         if ((fd = open(pipefs_dir, O_RDONLY)) == -1) {
 112                 printerr(0, "ERROR: failed to open %s: %s\n",
 113                          pipefs_dir, strerror(errno));
 114                 return;
 115         }
 116         fcntl(fd, F_SETSIG, DNOTIFY_SIGNAL);
 117         fcntl(fd, F_NOTIFY, DN_CREATE|DN_DELETE|DN_MODIFY|DN_MULTISHOT);
 118
 119         init_client_list();
 120
 121         while (1) {
 122                 while (dir_changed) {
 123                         dir_changed = 0;
 124                         printerr(2, "pipefs root dir changed\n");
 125                         if (update_client_list()) {
 126                                 printerr(0, "ERROR: couldn't update "
 127                                          "client list\n");
 128                                 goto out;
 129                         }
 130                 }
 131
 132                 /* every 5s cleanup possible zombies of child processes */
 133                 if (time(NULL) - child_check >= 5) {
 134                         printerr(3, "check zombie children...\n");
 135
 136                         while (1) {
 137                                 child_pid = waitpid(-1, NULL, WNOHANG);
 138                                 if (child_pid <= 0)
 139                                         break;
 140
 141                                 printerr(2, "terminate zombie child: %d\n",
 142                                          child_pid);
 143                         }
 144
 145                         child_check = time(NULL);
 146                 }
 147
 148                 /* race condition here: dir_changed could be set before we
 149                  * enter the poll, and we'd never notice if it weren't for the
 150                  * timeout. */
 151                 ret = poll(pollarray, pollsize, POLL_MILLISECS);
 152                 if (ret < 0) {
 153                         if (errno != EINTR)
 154                                 printerr(0,
 155                                          "WARNING: error return from poll\n");
 156                 } else if (ret == 0) {
 157                         /* timeout */
 158                 } else { /* ret > 0 */
 159                         scan_poll_results(ret);
 160                 }
 161         }
 162 out:
 163         close(fd);
 164         return;
 165 }