contrib/sendmail-8.14/libmilter/signal.c

   1 /*
   2  *  Copyright (c) 1999-2004, 2006 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 8.44 2006/03/03 03:42:04 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 static void     *mi_signal_thread __P((void *));
  25 static int       mi_spawn_signal_thread __P((char *));
  26
  27 /*
  28 **  MI_STOP -- return value of MilterStop
  29 **
  30 **      Parameters:
  31 **              none.
  32 **
  33 **      Returns:
  34 **              value of MilterStop
  35 */
  36
  37 int
  38 mi_stop()
  39 {
  40         return MilterStop;
  41 }
  42 /*
  43 **  MI_STOP_MILTERS -- set value of MilterStop
  44 **
  45 **      Parameters:
  46 **              v -- new value for MilterStop.
  47 **
  48 **      Returns:
  49 **              none.
  50 */
  51
  52 void
  53 mi_stop_milters(v)
  54         int v;
  55 {
  56         (void) smutex_lock(&M_Mutex);
  57         if (MilterStop < v)
  58                 MilterStop = v;
  59
  60         /* close listen socket */
  61         mi_closener();
  62         (void) smutex_unlock(&M_Mutex);
  63 }
  64 /*
  65 **  MI_CLEAN_SIGNALS -- clean up signal handler thread
  66 **
  67 **      Parameters:
  68 **              none.
  69 **
  70 **      Returns:
  71 **              none.
  72 */
  73
  74 void
  75 mi_clean_signals()
  76 {
  77         (void) smutex_destroy(&M_Mutex);
  78 }
  79 /*
  80 **  MI_SIGNAL_THREAD -- thread to deal with signals
  81 **
  82 **      Parameters:
  83 **              name -- name of milter
  84 **
  85 **      Returns:
  86 **              NULL
  87 */
  88
  89 static void *
  90 mi_signal_thread(name)
  91         void *name;
  92 {
  93         int sig, errs, sigerr;
  94         sigset_t set;
  95
  96         (void) sigemptyset(&set);
  97         (void) sigaddset(&set, SIGHUP);
  98         (void) sigaddset(&set, SIGTERM);
  99
 100         /* Handle Ctrl-C gracefully for debugging */
 101         (void) sigaddset(&set, SIGINT);
 102         errs = 0;
 103
 104         for (;;)
 105         {
 106                 sigerr = sig = 0;
 107 #if defined(SOLARIS) || defined(__svr5__)
 108                 if ((sig = sigwait(&set)) < 0)
 109 #else /* defined(SOLARIS) || defined(__svr5__) */
 110                 if ((sigerr = sigwait(&set, &sig)) != 0)
 111 #endif /* defined(SOLARIS) || defined(__svr5__) */
 112                 {
 113                         /* some OS return -1 and set errno: copy it */
 114                         if (sigerr <= 0)
 115                                 sigerr = errno;
 116
 117                         /* this can happen on OSF/1 (at least) */
 118                         if (sigerr == EINTR)
 119                                 continue;
 120                         smi_log(SMI_LOG_ERR,
 121                                 "%s: sigwait returned error: %d",
 122                                 (char *)name, sigerr);
 123                         if (++errs > MAX_FAILS_T)
 124                         {
 125                                 mi_stop_milters(MILTER_ABRT);
 126                                 return NULL;
 127                         }
 128                         continue;
 129                 }
 130                 errs = 0;
 131
 132                 switch (sig)
 133                 {
 134                   case SIGHUP:
 135                   case SIGTERM:
 136                         mi_stop_milters(MILTER_STOP);
 137                         return NULL;
 138                   case SIGINT:
 139                         mi_stop_milters(MILTER_ABRT);
 140                         return NULL;
 141                   default:
 142                         smi_log(SMI_LOG_ERR,
 143                                 "%s: sigwait returned unmasked signal: %d",
 144                                 (char *)name, sig);
 145                         break;
 146                 }
 147         }
 148         /* NOTREACHED */
 149 }
 150 /*
 151 **  MI_SPAWN_SIGNAL_THREAD -- spawn thread to handle signals
 152 **
 153 **      Parameters:
 154 **              name -- name of milter
 155 **
 156 **      Returns:
 157 **              MI_SUCCESS/MI_FAILURE
 158 */
 159
 160 static int
 161 mi_spawn_signal_thread(name)
 162         char *name;
 163 {
 164         sthread_t tid;
 165         int r;
 166         sigset_t set;
 167
 168         /* Mask HUP and KILL signals */
 169         (void) sigemptyset(&set);
 170         (void) sigaddset(&set, SIGHUP);
 171         (void) sigaddset(&set, SIGTERM);
 172         (void) sigaddset(&set, SIGINT);
 173
 174         if (pthread_sigmask(SIG_BLOCK, &set, NULL) != 0)
 175         {
 176                 smi_log(SMI_LOG_ERR,
 177                         "%s: Couldn't mask HUP and KILL signals", name);
 178                 return MI_FAILURE;
 179         }
 180         r = thread_create(&tid, mi_signal_thread, (void *)name);
 181         if (r != 0)
 182         {
 183                 smi_log(SMI_LOG_ERR,
 184                         "%s: Couldn't start signal thread: %d",
 185                         name, r);
 186                 return MI_FAILURE;
 187         }
 188         return MI_SUCCESS;
 189 }
 190 /*
 191 **  MI_CONTROL_STARTUP -- startup for thread to handle signals
 192 **
 193 **      Parameters:
 194 **              name -- name of milter
 195 **
 196 **      Returns:
 197 **              MI_SUCCESS/MI_FAILURE
 198 */
 199
 200 int
 201 mi_control_startup(name)
 202         char *name;
 203 {
 204
 205         if (!smutex_init(&M_Mutex))
 206         {
 207                 smi_log(SMI_LOG_ERR,
 208                         "%s: Couldn't initialize control pipe mutex", name);
 209                 return MI_FAILURE;
 210         }
 211
 212         /*
 213         **  spawn_signal_thread must happen before other threads are spawned
 214         **  off so that it can mask the right signals and other threads
 215         **  will inherit that mask.
 216         */
 217         if (mi_spawn_signal_thread(name) == MI_FAILURE)
 218         {
 219                 smi_log(SMI_LOG_ERR,
 220                         "%s: Couldn't spawn signal thread", name);
 221                 (void) smutex_destroy(&M_Mutex);
 222                 return MI_FAILURE;
 223         }
 224         return MI_SUCCESS;
 225 }