744 lines
18 KiB
C
744 lines
18 KiB
C
/* Copyright (c) 1993-1999 by Richard Kelsey and Jonathan Rees.
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See file COPYING. */
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#include "sysdep.h"
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#include <signal.h> /* for sigaction() (POSIX.1) */
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/times.h>
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#include <errno.h> /* for errno, (POSIX?/ANSI) */
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#include "c-mods.h"
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#include "scheme48vm.h"
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#include "event.h"
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#include "../scsh/scsh_aux.h"
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#include "../scsh/signals1.h"
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/* turning interrupts and I/O readiness into events */
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sigset_t full_sigset;
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#define block_interrupts(){sigprocmask (SIG_BLOCK, &full_sigset, 0);}
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#define allow_interrupts(){sigprocmask (SIG_UNBLOCK, &full_sigset, 0);}
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static void when_keyboard_interrupt();
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static void when_alarm_interrupt();
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static void when_sigpipe_interrupt();
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/* JMG:*/
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static void when_scsh_interrupt();
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/* JMG: for scsh */
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#define INTERRUPT_QUEUE_LENGTH 32
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static int interrupt_queue [INTERRUPT_QUEUE_LENGTH];
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static int next_interrupt = 0;
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static int s48_os_signal_pending(void);
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static bool s48_os_signal_happend(void);
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bool s48_setcatcher(int signum, void (*catcher)(int));
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void s48_start_alarm_interrupts(void);
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void
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s48_sysdep_init(void)
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{
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if (!s48_setcatcher(SIGINT, when_keyboard_interrupt)
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|| !s48_setcatcher(SIGALRM, when_alarm_interrupt)
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|| !s48_setcatcher(SIGPIPE, when_sigpipe_interrupt)) {
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fprintf(stderr,
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"Failed to install signal handlers, errno = %d\n",
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errno);
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exit(1);
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}
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sigfillset (&full_sigset);
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/* JMG: for scsh */
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s48_setcatcher(SIGCHLD, when_scsh_interrupt);
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s48_setcatcher(SIGCONT, when_scsh_interrupt);
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s48_setcatcher(SIGHUP, when_scsh_interrupt);
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s48_setcatcher(SIGQUIT, when_scsh_interrupt);
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s48_setcatcher(SIGTERM, when_scsh_interrupt);
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s48_setcatcher(SIGTSTP, when_scsh_interrupt);
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s48_setcatcher(SIGUSR1, when_scsh_interrupt);
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s48_setcatcher(SIGUSR2, when_scsh_interrupt);
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#ifdef SIGINFO
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s48_setcatcher(SIGINFO, when_scsh_interrupt);
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#endif
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#ifdef SIGIO
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s48_setcatcher(SIGIO, when_scsh_interrupt);
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#endif
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#if defined SIGPOLL && ((defined SIGIO && SIGPOLL != SIGIO) || \
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!defined SIGIO)
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s48_setcatcher(SIGPOLL, when_scsh_interrupt);
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#endif
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#ifdef SIGPROF
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s48_setcatcher(SIGPROF, when_scsh_interrupt);
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#endif
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#ifdef SIGPWR
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s48_setcatcher(SIGPWR, when_scsh_interrupt);
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#endif
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#ifdef SIGVTALRM
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s48_setcatcher(SIGVTALRM, when_scsh_interrupt);
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#endif
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#ifdef SIGWINCH
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s48_setcatcher(SIGWINCH, when_scsh_interrupt);
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#endif
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#ifdef SIGXCPU
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s48_setcatcher(SIGXCPU, when_scsh_interrupt);
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#endif
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#ifdef SIGXFSZ
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s48_setcatcher(SIGXFSZ, when_scsh_interrupt);
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#endif
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s48_start_alarm_interrupts();
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}
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/*
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* Unless a signal is being ignored, set up the handler.
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* If we return FALSE, something went wrong and errno is set to what.
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*/
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bool
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s48_setcatcher(int signum, void (*catcher)(int))
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{
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struct sigaction sa;
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if (sigaction(signum, (struct sigaction *)NULL, &sa) != 0){
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fprintf(stderr, "Failed to get sigaction for signal %d\n", signum);
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exit(1);
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}
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/* JMG: what's the point of not setting the handler in this case?
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if (sa.sa_handler == SIG_IGN)
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return (TRUE);*/
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sa.sa_handler = catcher;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = 0;
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if (sigaction(signum, &sa, (struct sigaction *)NULL) != 0){
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fprintf(stderr, "Failed to define handler for signal %d\n", signum);
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exit(1);
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}
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return (TRUE);
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}
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static long keyboard_interrupt_count = 0;
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static void
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when_keyboard_interrupt(int ign)
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{
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keyboard_interrupt_count += 1;
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NOTE_EVENT;
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return;
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}
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/*
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We turn off SIGPIPE interrupts by installing a handler that does nothing.
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Turning them off affects exec()'ed programs, so we don't want to do that.
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Any actual pipe problems are caught when we try to read or write to them.
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We thank Olin Shivers for this hack.
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*/
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static void
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when_sigpipe_interrupt(int ign)
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{
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return;
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}
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/* ticks since last timer-interrupt request */
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long s48_current_time = 0;
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static long alarm_time = -1;
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static long poll_time = -1;
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static long poll_interval = 5;
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static void
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when_alarm_interrupt(int ign)
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{
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s48_current_time += 1;
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/* fprintf(stderr, "[tick]"); */
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if ((alarm_time >= 0 && alarm_time <= s48_current_time) ||
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(poll_time >= 0 && poll_time <= s48_current_time)) {
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NOTE_EVENT;
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};
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return;
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}
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#define USEC_PER_POLL (1000000 / POLLS_PER_SECOND)
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/* delta is in ticks, 0 cancels current alarm */
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long
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s48_schedule_alarm_interrupt(long delta)
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{
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long old;
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/*
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fprintf(stderr, "<scheduling alarm for %ld + %ld>\n", s48_current_time,
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delta/TICKS_PER_POLL);
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*/
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/* get remaining time */
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if (alarm_time == -1)
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old = -1;
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else
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old = (alarm_time - s48_current_time) * TICKS_PER_POLL;
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/* decrement poll_time and reset current_time */
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if (poll_time != -1)
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poll_time -= s48_current_time;
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s48_current_time = 0;
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/* set alarm_time */
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if (delta == 0) {
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NOTE_EVENT;
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alarm_time = 0; }
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else
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alarm_time = delta / TICKS_PER_POLL;
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return old;
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}
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/* The next two procedures return times in seconds and ticks */
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long
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s48_real_time(long *ticks)
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{
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struct timeval tv;
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static struct timeval tv_orig;
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static int initp = 0;
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if (!initp) {
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gettimeofday(&tv_orig, NULL);
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initp = 1;
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};
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gettimeofday(&tv, NULL);
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*ticks = (tv.tv_usec - tv_orig.tv_usec)/(1000000/TICKS_PER_SECOND);
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return tv.tv_sec - tv_orig.tv_sec;
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}
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long
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s48_run_time(long *ticks)
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{
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struct tms time_buffer;
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static long clock_tick = 0;
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long cpu_time;
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if (clock_tick == 0)
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clock_tick = sysconf(_SC_CLK_TCK); /* POSIX.1, POSIX.2 */
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times(&time_buffer); /* On Sun, getrusage() would be better */
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cpu_time = time_buffer.tms_utime + time_buffer.tms_stime;
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*ticks = (cpu_time % clock_tick) * TICKS_PER_SECOND / clock_tick;
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return cpu_time / clock_tick;
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}
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void
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s48_start_alarm_interrupts(void)
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{
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struct itimerval new, old;
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new.it_value.tv_sec = 0;
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new.it_value.tv_usec = USEC_PER_POLL;
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new.it_interval.tv_sec = 0;
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new.it_interval.tv_usec = USEC_PER_POLL;
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if (0 != setitimer(ITIMER_REAL, &new, &old)) {
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perror("setitimer");
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exit(-1); }
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}
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void
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s48_stop_alarm_interrupts(void)
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{
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struct itimerval new, old;
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new.it_value.tv_sec = 0;
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new.it_value.tv_usec = 0;
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new.it_interval.tv_sec = 0;
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new.it_interval.tv_usec = 0;
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if (0 != setitimer(ITIMER_REAL, &new, &old)) {
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perror("setitimer");
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exit(-1); }
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}
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/*
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* ; Scheme version of the get-next-event procedure
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* ;
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* ; 1. If there has been a keyboard interrupt, return it.
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* ; 2. Check for ready ports if enough time has passed since the last check.
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* ; 3. If there is a ready port, return it.
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* ; 4. If an alarm is due, return it.
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* ; 5. If no events are pending, clear the event flags.
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* (define (get-next-event)
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* (cond ((> *keyboard-interrupt-count* 0)
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* (without-interrupts
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* (lambda ()
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* (set! *keyboard-interrupt-count*
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* (- *keyboard-interrupt-count* 1))))
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* (values (enum event-type keyboard-interrupt) #f #f))
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* (else
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* (cond ((>= *current_time* *poll-time*)
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* (queue-ready-ports)
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* (set! *poll-time* (+ *time* *poll-interval*))))
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* (cond ((not (queue-empty? ready-ports))
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* (values (enum event-type i/o-{read/write}-completion)
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* (dequeue! ready-ports)))
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* ((>= *current_time* *alarm-time*)
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* (set! *alarm-time* max-integer)
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* (values (enum event-type alarm-interrupt) #f))
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* (else
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* (without-interrupts
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* (lambda ()
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* (if (and (= *keyboard-interrupt-count* 0)
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* (> *alarm-time* *current_time*)
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* (> *poll-time* *current_time*))
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* (set! *pending-event?* #f))))
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* (values (enum event-type no-event) #f))))))
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*/
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#define FD_QUIESCENT 0 /* idle */
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#define FD_READY 1 /* I/O ready to be performed */
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#define FD_PENDING 2 /* waiting */
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typedef struct fd_struct {
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int fd, /* file descriptor */
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status; /* one of the FD_* constants */
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bool is_input; /* iff input */
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struct fd_struct *next; /* next on same queue */
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} fd_struct;
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static bool there_are_ready_ports(void);
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static fd_struct *next_ready_fd_struct(void);
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static int queue_ready_ports(bool wait, long seconds, long ticks);
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int
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s48_get_next_event(long *ready_fd, long *status)
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{
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/*
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extern int s48_os_signal_pending(void);
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*/
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int io_poll_status;
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fd_struct *f;
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/*
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fprintf(stderr, "[poll at %d (waiting for %d)]\n", s48_current_time, alarm_time);
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*/
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if (keyboard_interrupt_count > 0) {
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block_interrupts();
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--keyboard_interrupt_count;
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allow_interrupts();
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/* fprintf(stderr, "[keyboard interrupt]\n"); */
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return (KEYBOARD_INTERRUPT_EVENT);
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}
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if (poll_time != -1 && s48_current_time >= poll_time) {
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io_poll_status = queue_ready_ports(FALSE, 0, 0);
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if (io_poll_status == NO_ERRORS)
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poll_time = s48_current_time + poll_interval;
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else {
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*status = io_poll_status;
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return (ERROR_EVENT);
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}
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}
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if (there_are_ready_ports()) {
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f = next_ready_fd_struct();
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*ready_fd = f->fd;
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*status = 0; /* chars read or written */
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/* fprintf(stderr, "[i/o completion]\n"); */
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if (f->is_input)
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return (IO_READ_COMPLETION_EVENT);
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else
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return (IO_WRITE_COMPLETION_EVENT);
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}
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if (alarm_time != -1 && s48_current_time >= alarm_time) {
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alarm_time = -1;
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/* fprintf(stderr, "[alarm]\n"); */
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return (ALARM_EVENT);
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}
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block_interrupts();
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/* JMG: scsh should handle this */
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if (s48_os_signal_pending())
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return (OS_SIGNAL_EVENT);
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if ((keyboard_interrupt_count == 0)
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&& (alarm_time == -1 || s48_current_time < alarm_time)
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&& (poll_time == -1 || s48_current_time < poll_time))
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s48_Spending_eventsPS = FALSE;
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allow_interrupts();
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return (NO_EVENT);
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}
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/*
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* We keep two queues of ports: those that have a pending operation, and
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* those whose operation has completed. Periodically, we call select() on
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* the pending ports and move any that are ready onto the other queue and
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* signal an event.
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*/
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/*
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* A queue of fd_structs is empty iff the first field is NULL. In
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* that case, lastp points to first.
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*/
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typedef struct fdque {
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fd_struct *first,
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**lastp;
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} fdque;
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static fd_struct *fds[FD_SETSIZE];
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static fdque ready = {
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NULL,
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&ready.first
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},
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pending = {
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NULL,
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&pending.first
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};
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static void findrm(fd_struct *entry, fdque *que);
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static fd_struct *rmque(fd_struct **link, fdque *que);
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static void addque(fd_struct *entry, fdque *que);
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static fd_struct *add_fd(int fd, bool is_input);
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/*
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* Find a fd_struct in a queue, and remove it.
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*/
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static void
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findrm(fd_struct *entry, fdque *que)
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{
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fd_struct **fp,
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*f;
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for (fp = &que->first; (f = *fp) != entry; fp = &f->next)
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if (f == NULL) {
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fprintf(stderr, "ERROR: findrm fd %d, status %d not on queue.\n",
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entry->fd, entry->status);
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return;
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}
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rmque(fp, que);
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}
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/*
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* Given a pointer to the link of a fd_struct, and a pointer to
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* the queue it is on, remove the entry from the queue.
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* The entry removed is returned.
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*/
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static fd_struct *
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rmque(fd_struct **link, fdque *que)
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{
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fd_struct *res;
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res = *link;
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*link = res->next;
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if (res->next == NULL)
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que->lastp = link;
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return (res);
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}
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/*
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* Add a fd_struct to a queue.
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*/
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static void
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addque(fd_struct *entry, fdque *que)
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{
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*que->lastp = entry;
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entry->next = NULL;
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que->lastp = &entry->next;
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}
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static bool
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there_are_ready_ports(void)
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{
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return (ready.first != NULL);
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}
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static fd_struct *
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next_ready_fd_struct(void)
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{
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fd_struct *p;
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p = rmque(&ready.first, &ready);
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p->status = FD_QUIESCENT;
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return (p);
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}
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/*
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* Put fd on to the queue of ports with pending operations.
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* Return TRUE if successful, and FALSE otherwise.
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*/
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bool
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s48_add_pending_fd(int fd, bool is_input)
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{
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fd_struct *data;
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if (! (0 <= fd && fd < FD_SETSIZE)) {
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fprintf(stderr, "ERROR: add_pending fd %d not in [0, %d)\n",
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fd,
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FD_SETSIZE);
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return (FALSE);
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}
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data = fds[fd];
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if (data == NULL) {
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data = add_fd(fd, is_input);
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if (data == NULL)
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return (FALSE); /* no more memory */
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} else if (data->status == FD_PENDING)
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return (TRUE); /* fd is already pending */
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else if (data->status == FD_READY)
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findrm(data, &ready);
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data->status = FD_PENDING;
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addque(data, &pending);
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if (poll_time == -1)
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poll_time = s48_current_time + poll_interval;
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return TRUE;
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}
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/*
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* Add a new fd_struct for fd.
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*/
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static fd_struct *
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add_fd(int fd, bool is_input)
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{
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struct fd_struct *new;
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new = (struct fd_struct *)malloc(sizeof(*new));
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if (new != NULL) {
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new->fd = fd;
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new->status = FD_QUIESCENT;
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new->is_input = is_input;
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new->next = NULL;
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fds[fd] = new;
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}
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return (new);
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}
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/*
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* Remove fd from any queues it is on. Returns true if the FD was on a queue
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* and false if it wasn't.
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*/
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bool
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s48_remove_fd(int fd)
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{
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struct fd_struct *data;
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if (! (0 <= fd && fd < FD_SETSIZE)) {
|
|
fprintf(stderr, "ERROR: s48_remove_fd fd %d not in [0, %d)\n",
|
|
fd,
|
|
FD_SETSIZE);
|
|
return FALSE;
|
|
}
|
|
data = fds[fd];
|
|
if (data == NULL)
|
|
return FALSE;
|
|
if (data->status == FD_PENDING) {
|
|
findrm(data, &pending);
|
|
if (pending.first == NULL)
|
|
poll_time = -1;
|
|
} else if (data->status == FD_READY)
|
|
findrm(data, &ready);
|
|
free((void *)data);
|
|
fds[fd] = NULL;
|
|
return TRUE;
|
|
}
|
|
|
|
|
|
int
|
|
s48_wait_for_event(long max_wait, bool is_minutes)
|
|
{
|
|
int status;
|
|
long seconds,
|
|
ticks;
|
|
|
|
/* fprintf(stderr, "[waiting]\n"); */
|
|
|
|
s48_stop_alarm_interrupts();
|
|
ticks = 0;
|
|
if (max_wait == -1)
|
|
seconds = -1;
|
|
else if (is_minutes)
|
|
seconds = max_wait * 60;
|
|
else {
|
|
seconds = max_wait / TICKS_PER_SECOND;
|
|
ticks = max_wait % TICKS_PER_SECOND;
|
|
}
|
|
if (keyboard_interrupt_count > 0)
|
|
status = NO_ERRORS;
|
|
else if (s48_os_signal_happend ())
|
|
status = NO_ERRORS;
|
|
else {
|
|
status = queue_ready_ports(TRUE, seconds, ticks);
|
|
if (there_are_ready_ports())
|
|
NOTE_EVENT;
|
|
}
|
|
s48_start_alarm_interrupts();
|
|
return (status);
|
|
}
|
|
|
|
|
|
/*
|
|
* Call select() on the pending ports and move any ready ones to the ready
|
|
* queue. If wait is true, seconds is either -1 (wait forever) or the
|
|
* maximum number of seconds to wait (with ticks any additional ticks).
|
|
* The returned value is a status code.
|
|
*/
|
|
static int
|
|
queue_ready_ports(bool wait, long seconds, long ticks)
|
|
{
|
|
fd_set reads,
|
|
writes,
|
|
alls;
|
|
int limfd;
|
|
fd_struct *fdp,
|
|
**fdpp;
|
|
int left;
|
|
struct timeval tv,
|
|
*tvp;
|
|
|
|
if ((! wait)
|
|
&& (pending.first == NULL))
|
|
return (NO_ERRORS);
|
|
FD_ZERO(&reads);
|
|
FD_ZERO(&writes);
|
|
FD_ZERO(&alls);
|
|
limfd = 0;
|
|
for (fdp = pending.first; fdp != NULL; fdp = fdp->next) {
|
|
FD_SET(fdp->fd, fdp->is_input ? &reads : &writes);
|
|
FD_SET(fdp->fd, &alls);
|
|
if (limfd <= fdp->fd)
|
|
limfd = fdp->fd + 1;
|
|
}
|
|
tvp = &tv;
|
|
if (wait)
|
|
if (seconds == -1){
|
|
tvp = NULL;
|
|
}
|
|
else {
|
|
tv.tv_sec = seconds;
|
|
tv.tv_usec = ticks * (1000000 / TICKS_PER_SECOND);
|
|
}
|
|
else
|
|
timerclear(&tv);
|
|
while(TRUE) {
|
|
if ((keyboard_interrupt_count > 0) || s48_os_signal_happend ())
|
|
return NO_ERRORS;
|
|
/* time gap */
|
|
left = select(limfd, &reads, &writes, &alls, tvp);
|
|
if (left > 0) {
|
|
fdpp = &pending.first;
|
|
while (left > 0 && (fdp = *fdpp) != NULL)
|
|
if ((FD_ISSET(fdp->fd, &alls))
|
|
|| (FD_ISSET(fdp->fd, fdp->is_input ? &reads : &writes))) {
|
|
--left;
|
|
rmque(fdpp, &pending);
|
|
fdp->status = FD_READY;
|
|
addque(fdp, &ready);
|
|
} else
|
|
fdpp = &fdp->next;
|
|
if (pending.first == NULL)
|
|
poll_time = -1;
|
|
return NO_ERRORS;
|
|
}
|
|
else if (left == 0)
|
|
return NO_ERRORS;
|
|
else if (errno == EINTR) {
|
|
tvp = &tv; /* turn off blocking and try again */
|
|
timerclear(tvp);
|
|
}
|
|
else
|
|
return errno;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Adds `signum' to the queue of received signals.
|
|
*/
|
|
|
|
static void
|
|
queue_interrupt(int signum)
|
|
{
|
|
if (next_interrupt == INTERRUPT_QUEUE_LENGTH){
|
|
perror("Interrupt queue overflow -- report to Scheme 48 maintainers.");
|
|
exit(-1);
|
|
}
|
|
interrupt_queue[next_interrupt] = signum;
|
|
next_interrupt++;
|
|
}
|
|
|
|
/* JMG: for scsh */
|
|
static void when_scsh_interrupt(int signo)
|
|
{
|
|
queue_interrupt(sig2int[signo]);
|
|
NOTE_EVENT;
|
|
return;
|
|
}
|
|
|
|
|
|
/*
|
|
* This procedure is called periodically by the VM .
|
|
*
|
|
* s48_set_os_signal() is a VM procedure. The two arguments are the type
|
|
* of interrupt and one other value which can be used to return whatever
|
|
* associated information is desired. The two values, along with the
|
|
* current enabled-interrupts mask, are passed to the handler for os-signal
|
|
* interrupts.
|
|
*
|
|
* A handler can be installed by doing
|
|
(set-interrupt-handler! (enum interrupt os-signal)
|
|
(lambda (type arg enabled-interrupts)
|
|
(display type)
|
|
(newline)
|
|
(display arg)
|
|
(newline)
|
|
(display enabled-interrupts)
|
|
(newline)))
|
|
* The handler is called with all interrupts disabled. They are
|
|
* reenabled when the handler returns (or if done by hand).
|
|
*/
|
|
|
|
/*
|
|
* Returns TRUE if there is a signal to be delivered up to Scheme.
|
|
* Needs no be called with interrupts blocked.
|
|
*/
|
|
|
|
int
|
|
s48_os_signal_pending(void) {
|
|
int i;
|
|
s48_value interrupt_list = S48_NULL;
|
|
block_interrupts();
|
|
|
|
if (next_interrupt == 0) {
|
|
allow_interrupts();
|
|
return FALSE; }
|
|
else {
|
|
/* turn the queue into a scheme list and preserve the order */
|
|
for (i = next_interrupt; i > 0 ; i--)
|
|
interrupt_list = s48_cons (s48_enter_fixnum (interrupt_queue [i - 1]),
|
|
interrupt_list);
|
|
s48_set_os_signals(interrupt_list);
|
|
|
|
next_interrupt = 0;
|
|
allow_interrupts();
|
|
return TRUE; }
|
|
}
|
|
|
|
bool
|
|
s48_os_signal_happend(void) {
|
|
return (next_interrupt != 0);
|
|
}
|
|
|