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/*
* This software is Copyright 1989 by Jack Hudler.
*
* Permission is hereby granted to copy, reproduce, redistribute or otherwise
* use this software as long as: there is no monetary profit gained
* specifically from the use or reproduction or this software, it is not
* sold, rented, traded or otherwise marketed, and this copyright notice is
* included prominently in any copy made.
*
* The author make no claims as to the fitness or correctness of this software
* for any use whatsoever, and it is provided as is. Any use of this software
* is at the user's own risk.
*
*/
/****************************** Module Header ******************************\
* Module Name: alarm.c
* Created : 11-08-89
* Author : Jack Hudler [jack@csccat.lonestar.org]
* Copyright : 1988 Jack Hudler.
* Function : Unix like alarm signal simulator.
\***************************************************************************/
/* Tested using OS2 1.2 with Microsoft C 5.1 and 6.0. */
#define INCL_DOSPROCESS
#define INCL_DOSSIGNALS
#define INCL_DOS
#include <os2.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include "alarm.h"
#define ALARM_STACK 4096 /* This maybe over kill, but the page size is 4K */
static PBYTE pbAlarmStack;
static SEL selAlarmStack;
static TID tidAlarm;
static PID pidMain;
static BOOL bAlarmInit=FALSE;
static BOOL bAlarmRunning=FALSE;
static USHORT uTime;
static VOID FAR alarm_thread ( VOID )
{
while(1)
{
if (bAlarmRunning)
{
DosSleep(1000L);
uTime--;
if (uTime==0L)
{
// send signal to the main process.. I could have put raise() here
// however that would require the use of the multithreaded library,
// and it does not contain raise()!
// I tried it with the standard library, this signaled ok, but a
// test printf in the signal would not work and even caused SEGV.
// So I signal the process through OS/2 and then the process
// signals itself.
if (bAlarmRunning)
DosFlagProcess(pidMain,FLGP_PID, PFLG_A,1);
bAlarmRunning=FALSE;
}
}
else
DosSleep(500L);
}
}
static VOID PASCAL FAR AlarmSignal(USHORT usSigArg,USHORT usSigNum)
{
/*
* this is not executed from the thread. The thread triggers Process
* flag A which is in the main processes scope, this inturn triggers
* (via the raise) SIGUSR1 which is defined to SIGALRM.
*/
raise(SIGUSR1);
}
static void alarm_init(void)
{
PFNSIGHANDLER pfnPrev;
USHORT pfAction;
PIDINFO pid;
bAlarmInit = TRUE;
if (!DosAllocSeg( ALARM_STACK, (PSEL) &selAlarmStack, SEG_NONSHARED ))
{
OFFSETOF(pbAlarmStack) = ALARM_STACK - 2;
SELECTOROF(pbAlarmStack) = selAlarmStack;
/* Create the thread */
if (DosCreateThread( alarm_thread, &tidAlarm, pbAlarmStack ))
{
fprintf(stderr,"Alarm thread failed to start.\n");
exit(1);
}
/* Setup the signal handler for Process Flag A */
if (DosSetSigHandler(AlarmSignal,&pfnPrev,&pfAction,SIGA_ACCEPT,SIG_PFLG_A))
{
fprintf(stderr,"SigHandler Failed to install.\n");
exit(1);
}
/* Save main process ID, we'll need it for triggering the signal */
DosGetPID(&pid);
pidMain = pid.pid;
}
else
exit(1);
}
unsigned alarm(unsigned sec)
{
if (!bAlarmInit) alarm_init();
if (sec)
{
uTime = sec;
bAlarmRunning = TRUE;
}
else
bAlarmRunning = FALSE;
return 0;
}
#ifdef TESTING
/* A simple test to see if it works */
BOOL x;
void timeout(void)
{
fprintf(stderr,"ALARM TRIGGERED!!\n");
DosBeep(1000,500);
x++;
}
void main(void)
{
(void) signal(SIGALRM, timeout);
(void) alarm(1L);
printf("ALARM RUNNING!!\n");
while(!x);
}
#endif
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