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/****************************************************************
* *
* Copyright 2001, 2012 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include "mdef.h"
#include <signal.h>
#include <errno.h>
#include "error.h"
#include "gtmsiginfo.h"
#include "gtmimagename.h"
#include "have_crit.h"
#include "suspsigs_handler.h"
#define MAXINOUT 16
GBLREF volatile int suspend_status;
GBLREF uint4 process_id;
GBLREF volatile int4 exit_state;
GBLREF volatile int4 gtmMallocDepth; /* Recursion indicator */
GBLDEF uint4 sig_count=0;
void suspsigs_handler(int sig, siginfo_t* info, void *context)
{
sigset_t block_susp_sigs, oldsigmask;
int status;
switch(sig)
{
case SIGTTIN:
case SIGTTOU:
/* Terminal access while running in the background */
if (!IS_GTMSECSHR_IMAGE) /* Ignore signal if gtmsecshr */
{
if ((EXIT_NOTPENDING < exit_state) || !OK_TO_INTERRUPT)
{ /* Let the process run in the foreground till it finishes the terminal I/O */
if (EXIT_NOTPENDING == exit_state)
suspend_status = DEFER_SUSPEND;
status = kill(process_id, SIGCONT);
assert(0 == status);
/*
* If SIGCONT is not delivered before we go back to the I/O operation that caused
* SIGTTIN/OU, these signals can be generated again. In such cases,
* we might send ourselves an extra SIGCONT. The extra SIGCONT won't affect
* the I/O operation since we are running in the foreground already due to the
* first SIGCONT.
*/
sig_count++;
/* When process receives SIGTTIN or SIGTTOUT signal, it goes into suspend mode.
* If it is NOT OK_TO_INTERRUPT i.e. if process is holding some critical
* resources, the suspension of the process is deferred until the critical
* resources are released. It is not expected to arrive extra TTIN/TTOU signals
* between arrival of first TTIN/TTOU and actual suspension of the process.
* If such out of design situation arises, we limit the number of unexpected
* TTIN/TTOU to MAXINOUT and then GTMASSERT.
*/
if (MAXINOUT == sig_count)
GTMASSERT;
break;
}
suspend(sig);
}
break;
case SIGTSTP:
if (!IS_GTMSECSHR_IMAGE) /* not a good idea to suspend gtmsecshr */
{
if (EXIT_NOTPENDING == exit_state) /* not processing other signals */
{
if (!OK_TO_INTERRUPT)
{
suspend_status = DEFER_SUSPEND;
break;
}
suspend(sig);
}
}
break;
default:
GTMASSERT;
}
return;
}
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