87 lines
1.5 KiB
Go
87 lines
1.5 KiB
Go
/*
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* ewd123b.go
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*
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* A program to represent the second mutex strategy, as described in EWD123.
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*
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* Copyright (c) 2019-2019 HS Emden/Leer
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* All Rights Reserved.
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*
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* version 1.00 - 21 Oct 2019 - GJV - initial version
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*
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* author: Gert Veltink, gert.veltink@hs-emden-leer.de (GJV)
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*/
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package ewd123b
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import (
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"../controller"
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"log"
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)
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// global synchronization variables
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var c1, c2 = 1, 1
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// Start starts the execution of EWD123b.
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func Start() {
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go process1()
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go process2()
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/**
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*/
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}
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// process1 simulates the behaviour of the first process
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func process1() {
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L1:
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//wait till c2 = 0 (other process no longer inside critical section)
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if c2 == 0 {
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goto L1
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}
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//if the other process inspects c1 at this moment both will enter the critical section
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//we can force this behaviour if we wait for a moment
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//time.Sleep(100 * time.Millisecond)
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c1 = 0
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controller.EnterCriticalSection(1)
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controller.InsideCriticalSection(1, 50)
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controller.LeaveCriticalSection(1)
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c1 = 1
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controller.OutsideCriticalSection(1, 100)
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if controller.ProcessCrashed(0.1) {
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log.Println("Process 1 crashed")
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return
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}
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goto L1
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}
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// process2 simulates the behaviour of the second process
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func process2() {
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L2:
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if c1 == 0 {
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goto L2
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}
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c2 = 0
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controller.EnterCriticalSection(2)
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controller.InsideCriticalSection(2, 50)
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controller.LeaveCriticalSection(2)
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c2 = 1
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controller.OutsideCriticalSection(2, 100)
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if controller.ProcessCrashed(0.1) {
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log.Println("Process 2 crashed")
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return
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}
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goto L2
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}
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