/* KILLTASK -- Abort the currently executing task. Only call this when a task
* is to be killed spontaneously, as from interrupt, not when it is just dying
* due to a "bye" or eof.
* Close all pipes and pseudofiles, being careful not to close any that
* are real stdio files.
* Note that our function is to kill an external task, not the process in which
* it resides. The process is left running in the cache in case it is needed
* again.
*/
void
killtask (
register struct task *tp
)
{
char buf[128];
/* Print stack trace, with arguments.
*/
if (!(tp->t_ltp->lt_flags<_INVIS) && !(firstask->t_flags&T_BATCH) &&
!(strcmp (tp->t_ltp->lt_lname, "error") == 0))
printcall (currentask->t_stderr, tp);
/* If task is running in a subprocess, interrupt it and read the ERROR
* message. Not certain there isn't some case where this could cause
* deadlock, but it does not seem so. Interrupts are disabled during
* process startup. If task issues ERROR then it is popped before
* we are called, without issuing the signal.
*/
if (tp->t_pid != -1) {
fflush (tp->t_out);
c_prsignal (tp->t_pid, X_INT);
fgets (buf, 128, tp->t_in);
}
iofinish (tp);
}
/* ARGSUSED */
void
onint (
int *vex, /* virtual exception code */
int (**next_handler)(void) /* next handler to be called */
)
{
if (firstask->t_flags & T_BATCH) {
/* Batch task.
*/
iofinish (currentask);
bkg_abort();
clexit();
} else if (currentask->t_flags & (T_SCRIPT|T_CL|T_BUILTIN)) {
/* CL task.
*/
cl_error (E_UERR, "interrupt!!!");
} else {
/* External task connected via IPC. Pass the interrupt on to
* the child.
*/
c_prsignal (currentask->t_pid, X_INT);
/* Cancel any output and disable i/o on the tasks pseudofiles.
* This is necessary to cancel any i/o still buffered in the
* IPC channel. Commonly when the task is writing to STDOUT,
* for example, the CL will be writing the last buffer sent
* to the terminal, while the task waits after having already
* pushed the next buffer into the IPC. When we resume reading
* from the task we will see this buffered output on the next
* read and we wish to discard it. Leave STDERR connected to
* give a path to the terminal for recovery actions such as
* turning standout or graphics mode off. This gives the task
* a chance to cleanup but does not permit full recovery. The
* pseudofiles will be reconnected for the next task run.
*/
c_fseti (fileno(stdout), F_CANCEL, OK);
c_fseti (fileno(currentask->t_in), F_CANCEL, OK);
c_fseti (fileno(currentask->t_out), F_CANCEL, OK);
c_prredir (currentask->t_pid, STDIN, 0);
c_prredir (currentask->t_pid, STDOUT, 0);
/* If a subprocess is repeatedly interrupted we assume that it
* is hung in a loop and abort, advising the user to kill the
* process.
*/
if (++ninterrupts >= MAX_INTERRUPTS)
cl_error (E_UERR, "subprocess is hung; should be killed");
else
longjmp (intenv, 1);
}
*next_handler = NULL;
}
