contrib/sendmail/libmilter/signal.c

   1 /*
   2  *  Copyright (c) 1999-2002 Sendmail, Inc. and its suppliers.
   3  *      All rights reserved.
   4  *
   5  * By using this file, you agree to the terms and conditions set
   6  * forth in the LICENSE file which can be found at the top level of
   7  * the sendmail distribution.
   8  *
   9  */
  10
  11 #include <sm/gen.h>
  12 SM_RCSID("@(#)$Id: signal.c,v 8.37 2002/03/23 00:55:19 ca Exp $")
  13
  14 #include "libmilter.h"
  15
  16 /*
  17 **  thread to handle signals
  18 */
  19
  20 static smutex_t M_Mutex;
  21
  22 static int MilterStop = MILTER_CONT;
  23
  24 /*
  25 **  MI_STOP -- return value of MilterStop
  26 **
  27 **      Parameters:
  28 **              none.
  29 **
  30 **      Returns:
  31 **              value of MilterStop
  32 */
  33
  34 int
  35 mi_stop()
  36 {
  37         return MilterStop;
  38 }
  39 /*
  40 **  MI_STOP_MILTERS -- set value of MilterStop
  41 **
  42 **      Parameters:
  43 **              v -- new value for MilterStop.
  44 **
  45 **      Returns:
  46 **              none.
  47 */
  48
  49 void
  50 mi_stop_milters(v)
  51         int v;
  52 {
  53         (void) smutex_lock(&M_Mutex);
  54         if (MilterStop < v)
  55                 MilterStop = v;
  56
  57         /* close listen socket */
  58         mi_closener();
  59         (void) smutex_unlock(&M_Mutex);
  60 }
  61 /*
  62 **  MI_CLEAN_SIGNALS -- clean up signal handler thread
  63 **
  64 **      Parameters:
  65 **              none.
  66 **
  67 **      Returns:
  68 **              none.
  69 */
  70
  71 void
  72 mi_clean_signals()
  73 {
  74         (void) smutex_destroy(&M_Mutex);
  75 }
  76 /*
  77 **  MI_SIGNAL_THREAD -- thread to deal with signals
  78 **
  79 **      Parameters:
  80 **              name -- name of milter
  81 **
  82 **      Returns:
  83 **              NULL
  84 */
  85
  86 static void *
  87 mi_signal_thread(name)
  88         void *name;
  89 {
  90         int sig, errs;
  91         sigset_t set;
  92
  93         sigemptyset(&set);
  94         sigaddset(&set, SIGHUP);
  95         sigaddset(&set, SIGTERM);
  96
  97         /* Handle Ctrl-C gracefully for debugging */
  98         sigaddset(&set, SIGINT);
  99         errs = 0;
 100
 101         while (true)
 102         {
 103                 sig = 0;
 104 #if defined(SOLARIS) || defined(__svr5__)
 105                 if ((sig = sigwait(&set)) < 0)
 106 #else /* defined(SOLARIS) || defined(__svr5__) */
 107                 if (sigwait(&set, &sig) != 0)
 108 #endif /* defined(SOLARIS) || defined(__svr5__) */
 109                 {
 110                         smi_log(SMI_LOG_ERR,
 111                                 "%s: sigwait returned error: %d",
 112                                 (char *)name, errno);
 113                         if (++errs > MAX_FAILS_T)
 114                         {
 115                                 mi_stop_milters(MILTER_ABRT);
 116                                 return NULL;
 117                         }
 118                         continue;
 119                 }
 120                 errs = 0;
 121
 122                 switch (sig)
 123                 {
 124                   case SIGHUP:
 125                   case SIGTERM:
 126                         mi_stop_milters(MILTER_STOP);
 127                         return NULL;
 128                   case SIGINT:
 129                         mi_stop_milters(MILTER_ABRT);
 130                         return NULL;
 131                   default:
 132                         smi_log(SMI_LOG_ERR,
 133                                 "%s: sigwait returned unmasked signal: %d",
 134                                 (char *)name, sig);
 135                         break;
 136                 }
 137         }
 138 }
 139 /*
 140 **  MI_SPAWN_SIGNAL_THREAD -- spawn thread to handle signals
 141 **
 142 **      Parameters:
 143 **              name -- name of milter
 144 **
 145 **      Returns:
 146 **              MI_SUCCESS/MI_FAILURE
 147 */
 148
 149 static int
 150 mi_spawn_signal_thread(name)
 151         char *name;
 152 {
 153         sthread_t tid;
 154         int r;
 155         sigset_t set;
 156
 157         /* Mask HUP and KILL signals */
 158         sigemptyset(&set);
 159         sigaddset(&set, SIGHUP);
 160         sigaddset(&set, SIGTERM);
 161         sigaddset(&set, SIGINT);
 162
 163         if (pthread_sigmask(SIG_BLOCK, &set, NULL) != 0)
 164         {
 165                 smi_log(SMI_LOG_ERR,
 166                         "%s: Couldn't mask HUP and KILL signals", name);
 167                 return MI_FAILURE;
 168         }
 169         r = thread_create(&tid, mi_signal_thread, (void *)name);
 170         if (r != 0)
 171         {
 172                 smi_log(SMI_LOG_ERR,
 173                         "%s: Couldn't start signal thread: %d",
 174                         name, r);
 175                 return MI_FAILURE;
 176         }
 177         return MI_SUCCESS;
 178 }
 179 /*
 180 **  MI_CONTROL_STARTUP -- startup for thread to handle signals
 181 **
 182 **      Parameters:
 183 **              name -- name of milter
 184 **
 185 **      Returns:
 186 **              MI_SUCCESS/MI_FAILURE
 187 */
 188
 189 int
 190 mi_control_startup(name)
 191         char *name;
 192 {
 193
 194         if (!smutex_init(&M_Mutex))
 195         {
 196                 smi_log(SMI_LOG_ERR,
 197                         "%s: Couldn't initialize control pipe mutex", name);
 198                 return MI_FAILURE;
 199         }
 200
 201         /*
 202         **  spawn_signal_thread must happen before other threads are spawned
 203         **  off so that it can mask the right signals and other threads
 204         **  will inherit that mask.
 205         */
 206         if (mi_spawn_signal_thread(name) == MI_FAILURE)
 207         {
 208                 smi_log(SMI_LOG_ERR,
 209                         "%s: Couldn't spawn signal thread", name);
 210                 (void) smutex_destroy(&M_Mutex);
 211                 return MI_FAILURE;
 212         }
 213         return MI_SUCCESS;
 214 }