gno/bin/less/signal.c

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/*
* 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().
* If we happen to be reading from a file [in iread()] at the time
* the signal is received, we call intread to interrupt the iread.
*/
#pragma noroot
#include "less.h"
#include <signal.h>
#ifdef _ORCAC_
#pragma databank 1
segment "LoadSegONE";
#endif
/*
* "sigs" contains bits indicating signals which need to be processed.
*/
public int sigs;
#define S_INTERRUPT 01
#ifdef SIGTSTP
#define S_STOP 02
#endif
#if defined(SIGWINCH) || defined(SIGWIND)
#define S_WINCH 04
#endif
extern int sc_width, sc_height;
extern int swindow;
extern int screen_trashed;
extern int lnloop;
extern int linenums;
extern int scroll;
extern int reading;
static HANDLER u_interrupt(int type, int code);
static HANDLER stop(int type, int code);
/*
* Interrupt signal handler.
*/
/* ARGSUSED*/
static HANDLER
u_interrupt(type, code)
int type;
int code;
{
SIGNAL(SIGINT, u_interrupt);
sigs |= S_INTERRUPT;
if (reading)
intread();
}
public void
fake_interrupt(void)
{
sigs |= S_INTERRUPT;
}
#ifdef SIGTSTP
/*
* "Stop" (^Z) signal handler.
*/
/* ARGSUSED*/
static HANDLER
stop(type, code)
int type;
int code;
{
SIGNAL(SIGTSTP, stop);
sigs |= S_STOP;
if (reading)
intread();
}
#endif
#ifdef SIGWINCH
/*
* "Window" change handler
*/
/* ARGSUSED*/
public HANDLER
winch(type, code)
int type;
int code;
{
SIGNAL(SIGWINCH, winch);
sigs |= S_WINCH;
if (reading)
intread();
}
#else
#ifdef SIGWIND
/*
* "Window" change handler
*/
/* ARGSUSED*/
public HANDLER
winch(type)
int type;
{
SIGNAL(SIGWIND, winch);
sigs |= S_WINCH;
if (reading)
intread();
}
#endif
#endif
#ifdef __ORCAC__
#pragma databank 0
#endif
/*
* Set up the signal handlers.
*/
public void
init_signals(on)
int on;
{
if (on)
{
/*
* Set signal handlers.
*/
(void) SIGNAL(SIGINT, u_interrupt);
#ifdef SIGTSTP
(void) SIGNAL(SIGTSTP, stop);
#endif
#ifdef SIGWINCH
(void) SIGNAL(SIGWINCH, winch);
#else
#ifdef SIGWIND
(void) SIGNAL(SIGWIND, winch);
#endif
#endif
} else
{
/*
* Restore signals to defaults.
*/
(void) SIGNAL(SIGINT, SIG_DFL);
#ifdef SIGTSTP
(void) SIGNAL(SIGTSTP, SIG_DFL);
#endif
#ifdef SIGWINCH
(void) SIGNAL(SIGWINCH, SIG_IGN);
#endif
#ifdef SIGWIND
(void) SIGNAL(SIGWIND, SIG_IGN);
#endif
}
}
/*
* Process any signals we have received.
* A received signal cause a bit to be set in "sigs".
*/
public void
psignals(void)
{
register int tsignals;
if ((tsignals = sigs) == 0)
return;
sigs = 0;
#ifdef S_WINCH
if (tsignals & S_WINCH)
{
int old_width, old_height;
/*
* Re-execute get_term() to read the new window size.
*/
old_width = sc_width;
old_height = sc_height;
swindow = -1;
get_term();
if (sc_width != old_width || sc_height != old_height)
{
scroll = (sc_height + 1) / 2;
screen_trashed = 1;
}
}
#endif
#ifdef SIGTSTP
if (tsignals & S_STOP)
{
/*
* Clean up the terminal.
*/
#ifdef SIGTTOU
SIGNAL(SIGTTOU, SIG_IGN);
#endif
lower_left();
clear_eol();
deinit();
flush();
raw_mode(0);
#ifdef SIGTTOU
SIGNAL(SIGTTOU, SIG_DFL);
#endif
SIGNAL(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.
*/
SIGNAL(SIGTSTP, stop);
raw_mode(1);
init();
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 == 2)
screen_trashed = 1;
linenums = 0;
error("Line numbers turned off", NULL_PARG);
}
}
}