usr/src/lib/libc/port/nsl/mt.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #ifndef _LIBNSL_INCLUDE_MT_H
  28 #define _LIBNSL_INCLUDE_MT_H
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*
  33  * Threading and mutual exclusion declarations of primitives used for
  34  *      MT operation of libnsl code.
  35  *
  36  * Note: These primitives are designed to achieve the effect of avoiding a
  37  *       deadlock possibility by an interface operation being called from
  38  *       a signal handler while holding a lock.
  39  * Note: the sig_*() functions use the _sigoff() and _sigon() consolidation
  40  *       private interfaces provided by libc to defer all asynchronously
  41  *       generated signals for the duration of holding the lock.  Unlike
  42  *       blocking all signals with sigprocmask() or thr_sigsetmask(),
  43  *       _sigoff() allows signals with default dispositions to exercise
  44  *       their default actions (killing the process, stopping the process).
  45  */
  46
  47 #include <thread.h>
  48 #include <pthread.h>
  49 #include <signal.h>
  50 #include <synch.h>
  51
  52 #ifdef  __cplusplus
  53 extern "C" {
  54 #endif
  55
  56 extern sigset_t fillset;        /* for actually blocking all signals */
  57
  58 /*
  59  * sig_mutex_lock() and sig_mutex_unlock() are the same
  60  * as mutex_lock() and mutex_unlock() except that all
  61  * signals are deferred while the lock is held.  Likewise
  62  * for sig_rw_rdlock(), sig_rw_wrlock() and sig_rw_unlock().
  63  *
  64  * _sigoff() and _sigon() are consolidation-private
  65  * interfaces in libc that defer and enable signals.
  66  * Calls to these can nest but must be balanced, so
  67  * nested calls to these functions work properly.
  68  */
  69
  70 /* provided by libc in mtlib.h, but avoiding that include in nsl for now */
  71 extern void sig_mutex_lock(mutex_t *);
  72 extern void sig_mutex_unlock(mutex_t *);
  73
  74 extern void _sigoff(void);
  75 extern void _sigon(void);
  76
  77 #define sig_rw_rdlock(rwlp) do { _sigoff(); (void) rw_rdlock(rwlp); } while(0)
  78 #define sig_rw_wrlock(rwlp) do { _sigoff(); (void) rw_wrlock(rwlp); } while(0)
  79 #define sig_rw_unlock(rwlp) do { (void) rw_unlock(rwlp); _sigon(); } while(0)
  80
  81 extern void *thr_get_storage(pthread_key_t *, size_t, void(*)(void *));
  82
  83 #ifdef  __cplusplus
  84 }
  85 #endif
  86
  87 #endif  /* _LIBNSL_INCLUDE_MT_H */