/*
 * Listener loop for subsystem library libss.a.
 *
 *	$Header$
 *	$Locker$
 * 
 * Copyright 1987, 1988 by MIT Student Information Processing Board
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose is hereby granted, provided that
 * the names of M.I.T. and the M.I.T. S.I.P.B. not be used in
 * advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.  M.I.T. and the
 * M.I.T. S.I.P.B. make no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 */

#include "ss_internal.h"
#include <stdio.h>
#include <setjmp.h>
#include <signal.h>
#include <sys/param.h>
#ifdef BSD
#include <sgtty.h>
#endif

#ifndef	lint
static char const rcs_id[] =
    "$Header$";
#endif

typedef void sigret_t;

static ss_data *current_info;
static jmp_buf listen_jmpb;
static sigret_t (*sig_cont)(int);

static sigret_t print_prompt(int sig)
{
#ifdef BSD
    /* put input into a reasonable mode */
    struct sgttyb ttyb;
    if (ioctl(fileno(stdin), TIOCGETP, &ttyb) != -1) {
	if (ttyb.sg_flags & (CBREAK|RAW)) {
	    ttyb.sg_flags &= ~(CBREAK|RAW);
	    (void) ioctl(0, TIOCSETP, &ttyb);
	}
    }
#endif
    (void) fputs(current_info->prompt, stdout);
    (void) fflush(stdout);
}

static sigret_t listen_int_handler(int sig)
{
    putc('\n', stdout);
    signal(SIGINT, listen_int_handler);
    longjmp(listen_jmpb, 1);
}

int ss_listen (int sci_idx)
{
    char *cp;
    ss_data *info;
    sigret_t (*sig_int)(int), (*old_sig_cont)(int);
    char input[BUFSIZ];
#ifdef POSIX_SIGNALS
    sigset_t omask, igmask;
#else
    int mask;
#endif
    int code;
    jmp_buf old_jmpb;
    ss_data *old_info = current_info;
    
    current_info = info = ss_info(sci_idx);
    sig_cont = (sigret_t (*)(int)) 0;
    info->abort = 0;
#ifdef POSIX_SIGNALS
    sigemptyset(&igmask);
    sigaddset(&igmask, SIGINT);
    sigprocmask(SIG_BLOCK, &igmask, &omask);
#else
    mask = sigblock(sigmask(SIGINT));
#endif
    memcpy(old_jmpb, listen_jmpb, sizeof(jmp_buf));
    sig_int = signal(SIGINT, listen_int_handler);
    setjmp(listen_jmpb);
#ifdef POSIX_SIGNALS
    sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
#else
    (void) sigsetmask(mask);
#endif
    while(!info->abort) {
	print_prompt(0);
	old_sig_cont = sig_cont;
	sig_cont = signal(SIGCONT, print_prompt);
	if (sig_cont == print_prompt)
	    sig_cont = old_sig_cont;
	if (fgets(input, BUFSIZ, stdin) != input) {
	    code = SS_ET_EOF;
	    (void) signal(SIGCONT, sig_cont);
	    goto egress;
	}
	input[BUFSIZ-1] = 0;
	
	cp = strchr(input, '\n');
	if (cp) {
	    *cp = '\0';
	    if (cp == input)
		continue;
	}
	(void) signal(SIGCONT, sig_cont);

	code = ss_execute_line (sci_idx, input);
	if (code == SS_ET_COMMAND_NOT_FOUND) {
	    register char *c = input;
	    while (*c == ' ' || *c == '\t')
		c++;
	    cp = strchr (c, ' ');
	    if (cp)
		*cp = '\0';
	    cp = strchr (c, '\t');
	    if (cp)
		*cp = '\0';
	    ss_error (sci_idx, 0,
		    "Unknown request \"%s\".  Type \"?\" for a request list.",
		       c);
	}
    }
    code = 0;
egress:
    (void) signal(SIGINT, sig_int);
    memcpy(listen_jmpb, old_jmpb, sizeof(jmp_buf));
    current_info = old_info;
    return code;
}

void ss_abort_subsystem(int sci_idx, int code)
{
    ss_info(sci_idx)->abort = 1;
    ss_info(sci_idx)->exit_status = code;
    
}

void ss_quit(int argc, const char * const *argv, int sci_idx, pointer infop)
{
    ss_abort_subsystem(sci_idx, 0);
}