os161/userland/lib/hostcompat/hostcompat.c
2015-12-23 00:50:04 +00:00

239 lines
6.0 KiB
C

/*
* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
* The President and Fellows of Harvard College.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <unistd.h>
#include <termios.h>
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
#include "hostcompat.h"
/*
* The program name.
* This is used in err.c.
*/
const char *hostcompat_progname = NULL;
/*
* Unix tty state, for when we're running and to put it back the way it was,
* respectively.
*/
static struct termios hostcompat_runtios;
static struct termios hostcompat_savetios;
/*
* Put the tty state back the way it was.
*/
static
void
hostcompat_ttyreset(void)
{
tcsetattr(STDIN_FILENO, TCSADRAIN, &hostcompat_savetios);
}
/*
* Set the tty state back to the way we want it for running.
*/
static
void
hostcompat_ttyresume(void)
{
tcsetattr(STDIN_FILENO, TCSADRAIN, &hostcompat_runtios);
}
/*
* Set up the tty state stuff.
*/
static
int
hostcompat_ttysetup(void)
{
struct termios tios;
/* Get the current tty state. */
if (tcgetattr(STDIN_FILENO, &tios) < 0) {
/* stdin is not a tty */
return -1;
}
hostcompat_savetios = tios;
/* Turn off canonical ("cooked") input. */
tios.c_lflag &= ~ICANON;
/*
* With canonical input off, this says how many characters must be
* typed before read() will return.
*/
tios.c_cc[VMIN] = 1;
/* This can be used to set up read timeouts, but we don't need that. */
tios.c_cc[VTIME] = 0;
/* Turn off echoing of keypresses. */
tios.c_lflag &= ~(ECHO|ECHONL|ECHOCTL);
/* Do not support XON/XOFF flow control. */
tios.c_iflag &= ~(IXON|IXOFF);
/* On input, we want no CR/LF translation. */
tios.c_iflag &= ~(INLCR|IGNCR|ICRNL);
/* However, on output we want LF ('\n') mapped to CRLF. */
#ifdef OCRNL /* missing on OS X */
tios.c_oflag &= ~(OCRNL);
#endif
tios.c_oflag |= OPOST|ONLCR;
/* Enable keyboard signals (^C, ^Z, etc.) because they're useful. */
tios.c_lflag |= ISIG;
/* Set the new tty state. */
hostcompat_runtios = tios;
tcsetattr(STDIN_FILENO, TCSADRAIN, &tios);
return 0;
}
/*
* Signal handler for all the fatal signals (SIGSEGV, SIGTERM, etc.)
*/
static
void
hostcompat_die(int sig)
{
/* Set the tty back to the way we found it */
hostcompat_ttyreset();
/* Make sure the default action will occur when we get another signal*/
signal(sig, SIG_DFL);
/* Post the signal back to ourselves, to cause the right exit status.*/
kill(getpid(), sig);
/* Just in case. */
_exit(255);
}
/*
* Signal handler for the stop signals (SIGTSTP, SIGTTIN, etc.)
*/
static
void
hostcompat_stop(int sig)
{
/* Set the tty back to the way we found it */
hostcompat_ttyreset();
/* Make sure the default action will occur when we get another signal*/
signal(sig, SIG_DFL);
/* Post the signal back to ourselves. */
kill(getpid(), sig);
}
/*
* Signal handler for SIGCONT.
*/
static
void
hostcompat_cont(int sig)
{
(void)sig;
/* Set the tty to the way we want it for running. */
hostcompat_ttyresume();
/*
* Reload the signal handlers for stop/continue signals, in case
* they were set up with one-shot signals.
*/
signal(SIGTTIN, hostcompat_stop);
signal(SIGTTOU, hostcompat_stop);
signal(SIGTSTP, hostcompat_stop);
signal(SIGCONT, hostcompat_cont);
}
/*
* Initialize the hostcompat library.
*/
void
hostcompat_init(int argc, char *argv[])
{
/* Set the program name */
if (argc > 0 && argv[0] != NULL) {
hostcompat_progname = argv[0];
}
/* Set the tty modes */
if (hostcompat_ttysetup() < 0) {
return;
}
/* When exit() is called, clean up */
atexit(hostcompat_ttyreset);
/* stdout/stderr should be unbuffered */
setvbuf(stdout, NULL, _IONBF, 0);
setvbuf(stderr, NULL, _IONBF, 0);
/* Catch all the fatal signals, so we can clean up */
signal(SIGHUP, hostcompat_die);
signal(SIGINT, hostcompat_die);
signal(SIGQUIT, hostcompat_die);
signal(SIGILL, hostcompat_die);
signal(SIGTRAP, hostcompat_die);
signal(SIGABRT, hostcompat_die);
#ifdef SIGEMT
signal(SIGEMT, hostcompat_die);
#endif
signal(SIGFPE, hostcompat_die);
signal(SIGBUS, hostcompat_die);
signal(SIGSEGV, hostcompat_die);
signal(SIGSYS, hostcompat_die);
signal(SIGPIPE, hostcompat_die);
signal(SIGALRM, hostcompat_die);
signal(SIGTERM, hostcompat_die);
signal(SIGXCPU, hostcompat_die);
signal(SIGXFSZ, hostcompat_die);
signal(SIGVTALRM, hostcompat_die);
signal(SIGPROF, hostcompat_die);
signal(SIGUSR1, hostcompat_die);
signal(SIGUSR2, hostcompat_die);
/* Catch the stop signals, so we can adjust the tty */
signal(SIGTTIN, hostcompat_stop);
signal(SIGTTOU, hostcompat_stop);
signal(SIGTSTP, hostcompat_stop);
/* Catch the continue signal, so we can adjust the tty */
signal(SIGCONT, hostcompat_cont);
}