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os345signals.c
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os345signals.c
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// os345signal.c - signals
// ***********************************************************************
// ** DISCLAMER ** DISCLAMER ** DISCLAMER ** DISCLAMER ** DISCLAMER **
// ** **
// ** The code given here is the basis for the CS345 projects. **
// ** It comes "as is" and "unwarranted." As such, when you use part **
// ** or all of the code, it becomes "yours" and you are responsible to **
// ** understand any algorithm or method presented. Likewise, any **
// ** errors or problems become your responsibility to fix. **
// ** **
// ** NOTES: **
// ** -Comments beginning with "// ??" may require some implementation. **
// ** -Tab stops are set at every 3 spaces. **
// ** -The function API's in "OS345.h" should not be altered. **
// ** **
// ** DISCLAMER ** DISCLAMER ** DISCLAMER ** DISCLAMER ** DISCLAMER **
// ***********************************************************************
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <setjmp.h>
#include <assert.h>
#include "os345.h"
#include "os345signals.h"
extern TCB tcb[]; // task control block
extern int curTask; // current task #
// ***********************************************************************
// ***********************************************************************
// Call all pending task signal handlers
//
// return 1 if task is NOT to be scheduled.
//
int signals(void)
{
if (tcb[curTask].signal)
{
if (tcb[curTask].signal & mySIGCONT)
{
tcb[curTask].signal &= ~mySIGCONT;
(*tcb[curTask].sigContHandler)();
return 0;
}
if (tcb[curTask].signal & mySIGINT)
{
tcb[curTask].signal &= ~mySIGINT;
(*tcb[curTask].sigIntHandler)();
return 0;
}
if (tcb[curTask].signal & mySIGTERM)
{
tcb[curTask].signal &= ~mySIGTERM;
(*tcb[curTask].sigTermHandler)();
return 1;
}
if (tcb[curTask].signal & mySIGTSTP)
{
tcb[curTask].signal &= ~mySIGTSTP;
(*tcb[curTask].sigTstpHandler)();
return 1;
}
}
return 0;
}
// **********************************************************************
// **********************************************************************
// Register task signal handlers
//
int sigAction(void (*sigHandler)(void), int sig)
{
switch (sig)
{
case mySIGINT:
{
tcb[curTask].sigIntHandler = sigHandler; // mySIGINT handler
return 0;
}
case mySIGCONT:
{
tcb[curTask].sigContHandler = sigHandler;
return 0;
}
case mySIGTSTP:
{
tcb[curTask].sigTstpHandler = sigHandler;
return 1;
}
case mySIGTERM:
{
tcb[curTask].sigTermHandler = sigHandler;
return 1;
}
}
return 1;
}
// **********************************************************************
// sigSignal - send signal to task(s)
//
// taskId = task (-1 = all tasks)
// sig = signal
//
int sigSignal(int taskId, int sig)
{
// check for task
if ((taskId >= 0) && tcb[taskId].name)
{
tcb[taskId].signal |= sig;
return 0;
}
else if (taskId == -1)
{
for (taskId=0; taskId<MAX_TASKS; taskId++)
{
sigSignal(taskId, sig);
}
return 0;
}
// error
return 1;
}
// **********************************************************************
// **********************************************************************
// Default signal handlers
//
void defaultSigIntHandler(void) // task mySIGINT handler
{
printf("\nInt handler\n");
sigSignal(-1, mySIGTERM);
}
void defaultSigContHandler(void)
{
printf("\nCont handler\n");
return;
}
void defaultSigTstpHandler(void)
{
printf("\nTstp handler\n");
sigSignal(-1, mySIGSTOP);
}
void defaultSigTermHandler(void)
{
printf("\nTerm Handler\n");
killTask(curTask);
}
void createTaskSigHandlers(int tid)
{
tcb[tid].signal = 0;
if (tid)
{
// inherit parent signal handlers
tcb[tid].sigIntHandler = tcb[curTask].sigIntHandler; // mySIGINT handler
tcb[tid].sigContHandler = tcb[curTask].sigContHandler;
tcb[tid].sigTstpHandler = tcb[curTask].sigTstpHandler;
tcb[tid].sigTermHandler = tcb[curTask].sigTermHandler;
}
else
{
// otherwise use defaults
tcb[tid].sigIntHandler = defaultSigIntHandler; // task mySIGINT handler
tcb[tid].sigContHandler = defaultSigContHandler;
tcb[tid].sigTstpHandler = defaultSigTstpHandler;
tcb[tid].sigTermHandler = defaultSigTermHandler;
}
}