usr/src/lib/sun_fc/common/Lockable.cc

   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  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26
  27 #include "Lockable.h"
  28 #include <iostream>
  29 #include <cstdio>
  30 #include <cerrno>
  31 #include <unistd.h>
  32 #include <cstring>
  33
  34 using namespace std;
  35
  36 #define     DEADLOCK_WARNING 10
  37 #define     LOCK_SLEEP 1
  38
  39 /**
  40  * @memo            Create a lockable instance and initialize internal locks
  41  */
  42 Lockable::Lockable() {
  43         if (pthread_mutex_init(&mutex, NULL)) {
  44         }
  45 }
  46
  47 /**
  48  * @memo            Free up a lockable instance
  49  */
  50 Lockable::~Lockable() {
  51         if (pthread_mutex_destroy(&mutex)) {
  52         }
  53 }
  54
  55 /**
  56  * @memo            Unlock the instance
  57  * @precondition    This thread must have locked the instance
  58  * @postcondition   The instance will be unlocked
  59  */
  60 void Lockable::unlock() {
  61         unlock(&mutex);
  62 }
  63
  64 /**
  65  * @memo            Unlock a given mutex lock
  66  * @precondition    The lock must be held by this thread
  67  * @postcondition   The lock will be released
  68  * @param           myMutex The lock to unlock
  69  */
  70 void Lockable::unlock(pthread_mutex_t *myMutex) {
  71         pthread_mutex_unlock(myMutex);
  72 }
  73
  74 /**
  75  * @memo            Lock the instance
  76  * @postcondition   The lock will be held by this thread.
  77  */
  78 void Lockable::lock() {
  79         lock(&mutex);
  80 }
  81
  82 /**
  83  * @memo            Lock the given mutex lock
  84  * @postcondition   The lock will be held by this thread
  85  * @param           myMutex The mutex lock to take
  86  */
  87 void Lockable::lock(pthread_mutex_t *myMutex) {
  88         int status;
  89         int loop = 0;
  90         do {
  91             loop++;
  92             status = pthread_mutex_trylock(myMutex);
  93             if (status) {
  94                 switch (pthread_mutex_trylock(myMutex)) {
  95                 case EFAULT:
  96                     cerr << "Lock failed: Fault" << endl;
  97                     break;
  98                 case EINVAL:
  99                     cerr << "Lock failed: Invalid" << endl;
 100                     break;
 101                 case EBUSY:
 102                     if (loop > DEADLOCK_WARNING) {
 103                         cerr << "Lock failed: Deadlock" << endl;
 104                     }
 105                     break;
 106                 case EOWNERDEAD:
 107                     cerr << "Lock failed: Owner died" << endl;
 108                     break;
 109                 case ELOCKUNMAPPED:
 110                     cerr << "Lock failed: Unmapped" << endl;
 111                     break;
 112                 case ENOTRECOVERABLE:
 113                     cerr << "Lock failed: not recoverable" << endl;
 114                 default:
 115                     if (loop > DEADLOCK_WARNING) {
 116                         cerr << "Lock failed: " <<strerror(status) << endl;
 117                         break;
 118                     }
 119                 }
 120             } else {
 121                 break; // Lock taken succesfully
 122             }
 123             sleep(LOCK_SLEEP);
 124         } while (status);
 125 }