external/bsd/bind/dist/lib/isc/win32/app.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2004, 2007, 2009  Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (C) 1999-2001  Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  12  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  13  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  14  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  15  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  16  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  17  * PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 /* Id: app.c,v 1.9 2009/09/02 23:48:03 tbox Exp */
  21
  22 #include <config.h>
  23
  24 #include <sys/types.h>
  25
  26 #include <stddef.h>
  27 #include <stdlib.h>
  28 #include <errno.h>
  29 #include <unistd.h>
  30 #include <process.h>
  31
  32 #include <isc/app.h>
  33 #include <isc/boolean.h>
  34 #include <isc/condition.h>
  35 #include <isc/msgs.h>
  36 #include <isc/mutex.h>
  37 #include <isc/event.h>
  38 #include <isc/platform.h>
  39 #include <isc/string.h>
  40 #include <isc/task.h>
  41 #include <isc/time.h>
  42 #include <isc/util.h>
  43 #include <isc/thread.h>
  44
  45 static isc_eventlist_t  on_run;
  46 static isc_mutex_t      lock;
  47 static isc_boolean_t    shutdown_requested = ISC_FALSE;
  48 static isc_boolean_t    running = ISC_FALSE;
  49 /*
  50  * We assume that 'want_shutdown' can be read and written atomically.
  51  */
  52 static isc_boolean_t    want_shutdown = ISC_FALSE;
  53 /*
  54  * We assume that 'want_reload' can be read and written atomically.
  55  */
  56 static isc_boolean_t    want_reload = ISC_FALSE;
  57
  58 static isc_boolean_t    blocked  = ISC_FALSE;
  59
  60 static isc_thread_t     blockedthread;
  61
  62 /* Events to wait for */
  63
  64 #define NUM_EVENTS 2
  65
  66 enum {
  67         RELOAD_EVENT,
  68         SHUTDOWN_EVENT
  69 };
  70
  71 static HANDLE hEvents[NUM_EVENTS];
  72 DWORD  dwWaitResult;
  73
  74 /*
  75  * We need to remember which thread is the main thread...
  76  */
  77 static isc_thread_t     main_thread;
  78
  79 isc_result_t
  80 isc__app_start(void) {
  81         isc_result_t result;
  82
  83         /*
  84          * Start an ISC library application.
  85          */
  86
  87         main_thread = GetCurrentThread();
  88
  89         result = isc_mutex_init(&lock);
  90         if (result != ISC_R_SUCCESS)
  91                 return (result);
  92
  93         /* Create the reload event in a non-signaled state */
  94         hEvents[RELOAD_EVENT] = CreateEvent(NULL, FALSE, FALSE, NULL);
  95
  96         /* Create the shutdown event in a non-signaled state */
  97         hEvents[SHUTDOWN_EVENT] = CreateEvent(NULL, FALSE, FALSE, NULL);
  98
  99         ISC_LIST_INIT(on_run);
 100         return (ISC_R_SUCCESS);
 101 }
 102
 103 isc_result_t
 104 isc__app_onrun(isc_mem_t *mctx, isc_task_t *task, isc_taskaction_t action,
 105               void *arg) {
 106         isc_event_t *event;
 107         isc_task_t *cloned_task = NULL;
 108         isc_result_t result;
 109
 110
 111         LOCK(&lock);
 112         if (running) {
 113                 result = ISC_R_ALREADYRUNNING;
 114                 goto unlock;
 115         }
 116
 117         /*
 118          * Note that we store the task to which we're going to send the event
 119          * in the event's "sender" field.
 120          */
 121         isc_task_attach(task, &cloned_task);
 122         event = isc_event_allocate(mctx, cloned_task, ISC_APPEVENT_SHUTDOWN,
 123                                    action, arg, sizeof(*event));
 124         if (event == NULL) {
 125                 result = ISC_R_NOMEMORY;
 126                 goto unlock;
 127         }
 128
 129         ISC_LIST_APPEND(on_run, event, ev_link);
 130         result = ISC_R_SUCCESS;
 131
 132  unlock:
 133         UNLOCK(&lock);
 134         return (result);
 135 }
 136
 137 isc_result_t
 138 isc__app_run(void) {
 139         isc_event_t *event, *next_event;
 140         isc_task_t *task;
 141         HANDLE *pHandles = NULL;
 142
 143         REQUIRE(main_thread == GetCurrentThread());
 144         LOCK(&lock);
 145         if (!running) {
 146                 running = ISC_TRUE;
 147
 148                 /*
 149                  * Post any on-run events (in FIFO order).
 150                  */
 151                 for (event = ISC_LIST_HEAD(on_run);
 152                      event != NULL;
 153                      event = next_event) {
 154                         next_event = ISC_LIST_NEXT(event, ev_link);
 155                         ISC_LIST_UNLINK(on_run, event, ev_link);
 156                         task = event->ev_sender;
 157                         event->ev_sender = NULL;
 158                         isc_task_sendanddetach(&task, &event);
 159                 }
 160
 161         }
 162
 163         UNLOCK(&lock);
 164
 165         /*
 166          * There is no danger if isc_app_shutdown() is called before we wait
 167          * for events.
 168          */
 169
 170         while (!want_shutdown) {
 171                 dwWaitResult = WaitForMultipleObjects(NUM_EVENTS, hEvents,
 172                                                       FALSE, INFINITE);
 173
 174                 /* See why we returned */
 175
 176                 if (WaitSucceeded(dwWaitResult, NUM_EVENTS)) {
 177                         /*
 178                          * The return was due to one of the events
 179                          * being signaled
 180                          */
 181                         switch (WaitSucceededIndex(dwWaitResult)) {
 182                         case RELOAD_EVENT:
 183                                 want_reload = ISC_TRUE;
 184                                 break;
 185
 186                         case SHUTDOWN_EVENT:
 187                                 want_shutdown = ISC_TRUE;
 188                                 break;
 189                         }
 190                 }
 191                 if (want_reload) {
 192                         want_reload = ISC_FALSE;
 193                         return (ISC_R_RELOAD);
 194                 }
 195
 196                 if (want_shutdown && blocked)
 197                         exit(-1);
 198         }
 199
 200         return (ISC_R_SUCCESS);
 201 }
 202
 203 isc_result_t
 204 isc__app_shutdown(void) {
 205         isc_boolean_t want_kill = ISC_TRUE;
 206
 207         LOCK(&lock);
 208         REQUIRE(running);
 209
 210         if (shutdown_requested)
 211                 want_kill = ISC_FALSE;          /* We're only signaling once */
 212         else
 213                 shutdown_requested = ISC_TRUE;
 214
 215         UNLOCK(&lock);
 216         if (want_kill)
 217                 SetEvent(hEvents[SHUTDOWN_EVENT]);
 218
 219         return (ISC_R_SUCCESS);
 220 }
 221
 222 isc_result_t
 223 isc__app_reload(void) {
 224         isc_boolean_t want_reload = ISC_TRUE;
 225
 226         LOCK(&lock);
 227         REQUIRE(running);
 228
 229         /*
 230          * Don't send the reload signal if we're shutting down.
 231          */
 232         if (shutdown_requested)
 233                 want_reload = ISC_FALSE;
 234
 235         UNLOCK(&lock);
 236         if (want_reload)
 237                 SetEvent(hEvents[RELOAD_EVENT]);
 238
 239         return (ISC_R_SUCCESS);
 240 }
 241
 242 void
 243 isc__app_finish(void) {
 244         DESTROYLOCK(&lock);
 245 }
 246
 247 void
 248 isc__app_block(void) {
 249         REQUIRE(running);
 250         REQUIRE(!blocked);
 251
 252         blocked = ISC_TRUE;
 253         blockedthread = GetCurrentThread();
 254 }
 255
 256 void
 257 isc__app_unblock(void) {
 258         REQUIRE(running);
 259         REQUIRE(blocked);
 260         blocked = ISC_FALSE;
 261         REQUIRE(blockedthread == GetCurrentThread());
 262 }