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/*
* Copyright (C) 1984-2002 Mark Nudelman
*
* You may distribute under the terms of either the GNU General Public
* License or the Less License, as specified in the README file.
*
* For more information about less, or for information on how to
* contact the author, see the README file.
*/
/*
* Routines dealing with signals.
*
* A signal usually merely causes a bit to be set in the "signals" word.
* At some convenient time, the mainline code checks to see if any
* signals need processing by calling psignal().
*/
#include "less.h"
#include <signal.h>
/*
* "sigs" contains bits indicating signals which need to be processed.
*/
public int sigs;
extern int sc_width, sc_height;
extern int screen_trashed;
extern int lnloop;
extern int linenums;
extern int wscroll;
/*
* Interrupt signal handler.
*/
/* ARGSUSED*/
static RETSIGTYPE
u_interrupt(type)
int type;
{
#if OS2
LSIGNAL(SIGINT, SIG_ACK);
#endif
sigs |= S_INTERRUPT;
#if MSDOS_COMPILER==DJGPPC
/*
* If a keyboard has been hit, it must be Ctrl-C
* (as opposed to Ctrl-Break), so consume it.
* (Otherwise, Less will beep when it sees Ctrl-C from keyboard.)
*/
if (kbhit())
getkey();
#endif
}
#ifdef SIGTSTP
/*
* "Stop" (^Z) signal handler.
*/
/* ARGSUSED*/
static RETSIGTYPE
stop(type)
int type;
{
sigs |= S_STOP;
}
#endif
#ifdef SIGWINCH
/*
* "Window" change handler
*/
/* ARGSUSED*/
public RETSIGTYPE
winch(type)
int type;
{
sigs |= S_WINCH;
}
#else
#ifdef SIGWIND
/*
* "Window" change handler
*/
/* ARGSUSED*/
public RETSIGTYPE
winch(type)
int type;
{
sigs |= S_WINCH;
}
#endif
#endif
#if MSDOS_COMPILER==WIN32C
/*
* Handle CTRL-C and CTRL-BREAK keys.
*/
#include "windows.h"
static BOOL WINAPI
wbreak_handler(dwCtrlType)
DWORD dwCtrlType;
{
switch (dwCtrlType)
{
case CTRL_C_EVENT:
case CTRL_BREAK_EVENT:
sigs |= S_INTERRUPT;
return (TRUE);
default:
break;
}
return (FALSE);
}
#endif
/*
* Set up the signal handlers.
*/
public void
init_signals(on)
int on;
{
if (on)
{
/*
* Set signal handlers.
*/
(void) LSIGNAL(SIGINT, u_interrupt);
#if MSDOS_COMPILER==WIN32C
SetConsoleCtrlHandler(wbreak_handler, TRUE);
#endif
#ifdef SIGTSTP
(void) LSIGNAL(SIGTSTP, stop);
#endif
#ifdef SIGWINCH
(void) LSIGNAL(SIGWINCH, winch);
#else
#ifdef SIGWIND
(void) LSIGNAL(SIGWIND, winch);
#endif
#ifdef SIGQUIT
(void) LSIGNAL(SIGQUIT, SIG_IGN);
#endif
#endif
} else
{
/*
* Restore signals to defaults.
*/
(void) LSIGNAL(SIGINT, SIG_DFL);
#if MSDOS_COMPILER==WIN32C
SetConsoleCtrlHandler(wbreak_handler, FALSE);
#endif
#ifdef SIGTSTP
(void) LSIGNAL(SIGTSTP, SIG_DFL);
#endif
#ifdef SIGWINCH
(void) LSIGNAL(SIGWINCH, SIG_IGN);
#endif
#ifdef SIGWIND
(void) LSIGNAL(SIGWIND, SIG_IGN);
#endif
#ifdef SIGQUIT
(void) LSIGNAL(SIGQUIT, SIG_DFL);
#endif
}
}
/*
* Process any signals we have received.
* A received signal cause a bit to be set in "sigs".
*/
public void
psignals()
{
register int tsignals;
if ((tsignals = sigs) == 0)
return;
sigs = 0;
#ifdef SIGTSTP
if (tsignals & S_STOP)
{
/*
* Clean up the terminal.
*/
#ifdef SIGTTOU
LSIGNAL(SIGTTOU, SIG_IGN);
#endif
clear_bot();
deinit();
flush();
raw_mode(0);
#ifdef SIGTTOU
LSIGNAL(SIGTTOU, SIG_DFL);
#endif
LSIGNAL(SIGTSTP, SIG_DFL);
kill(getpid(), SIGTSTP);
/*
* ... Bye bye. ...
* Hopefully we'll be back later and resume here...
* Reset the terminal and arrange to repaint the
* screen when we get back to the main command loop.
*/
LSIGNAL(SIGTSTP, stop);
raw_mode(1);
init();
screen_trashed = 1;
tsignals |= S_WINCH;
}
#endif
#ifdef S_WINCH
if (tsignals & S_WINCH)
{
int old_width, old_height;
/*
* Re-execute scrsize() to read the new window size.
*/
old_width = sc_width;
old_height = sc_height;
get_term();
if (sc_width != old_width || sc_height != old_height)
{
wscroll = (sc_height + 1) / 2;
screen_trashed = 1;
}
}
#endif
if (tsignals & S_INTERRUPT)
{
bell();
/*
* {{ You may wish to replace the bell() with
* error("Interrupt", NULL_PARG); }}
*/
/*
* If we were interrupted while in the "calculating
* line numbers" loop, turn off line numbers.
*/
if (lnloop)
{
lnloop = 0;
if (linenums == OPT_ONPLUS)
screen_trashed = 1;
linenums = 0;
error("Line numbers turned off", NULL_PARG);
}
}
}
/*
* Custom version of signal() that causes syscalls to be interrupted.
*/
public void
(*lsignal(s, a))()
int s;
void (*a) ();
{
struct sigaction sa, osa;
sa.sa_handler = a;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0; /* don't restart system calls */
if (sigaction(s, &sa, &osa) != 0)
return (SIG_ERR);
return (osa.sa_handler);
}
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