screen.c

/*
 *	Top users/processes display for Unix
 *	Version 3
 *
 *	This program may be freely redistributed,
 *	but this entire comment MUST remain intact.
 *
 *	Copyright (c) 1984, 1989, William LeFebvre, Rice University
 *	Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University
 */

/*	This file contains the routines that interface to termcap and stty/gtty.
 *
 *	Paul Vixie, February 1987: converted to use ioctl() instead of stty/gtty.
 *
 *	I put in code to turn on the TOSTOP bit while top was running, but I
 *	didn't really like the results.  If you desire it, turn on the
 *	preprocessor variable "TOStop".   --wnl
 */

#include "os.h"
#include "pg_top.h"

#include <sys/ioctl.h>
#ifdef CBREAK
#include <sgtty.h>
#define SGTTY
#else
#include <termios.h>
#endif /* CBREAK */
#ifndef TAB3
#ifdef OXTABS
#define TAB3 OXTABS
#else
#define TAB3 0
#endif /* OXTABS */
#endif
#include "screen.h"
#include "boolean.h"

extern char *myname;

int			overstrike;
int			screen_length;
int			screen_width;
char		ch_erase;
char		ch_kill;
char		smart_terminal;
char		PC;
char	   *tgetstr();
char	   *tgoto();
char		termcap_buf[1024];
char		string_buffer[1024];
char		home[16];
char		lower_left[15];
char	   *clear_line;
char	   *clear_screen;
char	   *clear_to_end;
char	   *cursor_motion;
char	   *start_standout;
char	   *end_standout;
char	   *terminal_init;
char	   *terminal_end;

#ifdef SGTTY
static struct sgttyb old_settings;
static struct sgttyb new_settings;
#endif
static struct termios old_settings;
static struct termios new_settings;
static char is_a_terminal = No;

#ifdef TOStop
static int	old_lword;
static int	new_lword;
#endif

#define STDIN	0
#define STDOUT	1
#define STDERR	2

/* This has to be defined as a subroutine for tputs (instead of a macro) */

int
putstdout(int ch)
{
	return putchar((unsigned int) ch);
}

void
get_screensize()
{

#ifdef TIOCGWINSZ

	struct winsize ws;

	if (ioctl(1, TIOCGWINSZ, &ws) != -1)
	{
		if (ws.ws_row != 0)
		{
			screen_length = ws.ws_row;
		}
		if (ws.ws_col != 0)
		{
			screen_width = ws.ws_col - 1;
		}
	}
#else
#ifdef TIOCGSIZE

	struct ttysize ts;

	if (ioctl(1, TIOCGSIZE, &ts) != -1)
	{
		if (ts.ts_lines != 0)
		{
			screen_length = ts.ts_lines;
		}
		if (ts.ts_cols != 0)
		{
			screen_width = ts.ts_cols - 1;
		}
	}
#endif							/* TIOCGSIZE */
#endif							/* TIOCGWINSZ */

	char	   *lower_left_motion = "";

	/* get_screensize() can be called from main() without cursor_motion */
	/* having been set, so we protect against that possibility. */
	if (smart_terminal == Yes)
	{
		/* We need to account for the fact that tgoto() might return NULL. */
		lower_left_motion = tgoto(cursor_motion, 0, screen_length - 1);
		if (lower_left_motion == NULL)
		{
			lower_left_motion = "";
		}
	}
	(void) strncpy(lower_left, lower_left_motion, 15);
	lower_left[14] = '\0';
}

void
init_termcap(int interactive)
{
	char	   *bufptr;
	char	   *PCptr;
	char	   *term_name;
	char	   *getenv();
	int			status;

	/* set defaults in case we aren't smart */
	screen_width = MAX_COLS;
	screen_length = 0;

	if (!interactive)
	{
		/* pretend we have a dumb terminal */
		smart_terminal = No;
		return;
	}

	/* assume we have a smart terminal until proven otherwise */
	smart_terminal = Yes;

	/* get the terminal name */
	term_name = getenv("TERM");

	/* if there is no TERM, assume it's a dumb terminal */
	/* patch courtesy of Sam Horrocks at telegraph.ics.uci.edu */
	if (term_name == NULL)
	{
		smart_terminal = No;
		return;
	}

	/* now get the termcap entry */
	if ((status = tgetent(termcap_buf, term_name)) != 1)
	{
		if (status == -1)
		{
			fprintf(stderr, "%s: can't open termcap file\n", myname);
		}
		else
		{
			fprintf(stderr, "%s: no termcap entry for a `%s' terminal\n",
					myname, term_name);
		}

		/* pretend it's dumb and proceed */
		smart_terminal = No;
		return;
	}

	/* "hardcopy" immediately indicates a very stupid terminal */
	if (tgetflag("hc"))
	{
		smart_terminal = No;
		return;
	}

	/* set up common terminal capabilities */
	if ((screen_length = tgetnum("li")) <= 0)
	{
		screen_length = smart_terminal = 0;
		return;
	}

	/* screen_width is a little different */
	if ((screen_width = tgetnum("co")) == -1)
	{
		screen_width = 79;
	}
	else
	{
		screen_width -= 1;
	}

	/* terminals that overstrike need special attention */
	overstrike = tgetflag("os");

	/* initialize the pointer into the termcap string buffer */
	bufptr = string_buffer;

	/* get "ce", clear to end */
	if (!overstrike)
	{
		clear_line = tgetstr("ce", &bufptr);
	}

	/* get necessary capabilities */
	if ((clear_screen = tgetstr("cl", &bufptr)) == NULL ||
		(cursor_motion = tgetstr("cm", &bufptr)) == NULL)
	{
		smart_terminal = No;
		return;
	}

	/* get some more sophisticated stuff -- these are optional */
	clear_to_end = tgetstr("cd", &bufptr);
	terminal_init = tgetstr("ti", &bufptr);
	terminal_end = tgetstr("te", &bufptr);
	start_standout = tgetstr("so", &bufptr);
	end_standout = tgetstr("se", &bufptr);

	/* pad character */
	PC = (PCptr = tgetstr("pc", &bufptr)) ? *PCptr : 0;

	/* set convenience strings */
	/* We need to account for the fact that tgoto() might return NULL. */
	char	   *home_motion = tgoto(cursor_motion, 0, 0);

	if (home_motion == NULL)
	{
		home_motion = "";
	}
	(void) strncpy(home, home_motion, 15);
	home[15] = '\0';
	/* (lower_left is set in get_screensize) */

	/* get the actual screen size with an ioctl, if needed */

	/*
	 * This may change screen_width and screen_length, and it always sets
	 * lower_left.
	 */
	get_screensize();

	/* if stdout is not a terminal, pretend we are a dumb terminal */
#ifdef SGTTY
	if (ioctl(STDOUT, TIOCGETP, &old_settings) == -1)
	{
		smart_terminal = No;
	}
#endif
	if (tcgetattr(STDOUT, &old_settings) == -1)
	{
		smart_terminal = No;
	}
}

void
init_screen()
{
	/* get the old settings for safe keeping */
#ifdef SGTTY
	if (ioctl(STDOUT, TIOCGETP, &old_settings) != -1)
	{
		/* copy the settings so we can modify them */
		new_settings = old_settings;

		/* turn on CBREAK and turn off character echo and tab expansion */
		new_settings.sg_flags |= CBREAK;
		new_settings.sg_flags &= ~(ECHO | XTABS);
		(void) ioctl(STDOUT, TIOCSETP, &new_settings);

		/* remember the erase and kill characters */
		ch_erase = old_settings.sg_erase;
		ch_kill = old_settings.sg_kill;

#ifdef TOStop
		/* get the local mode word */
		(void) ioctl(STDOUT, TIOCLGET, &old_lword);

		/* modify it */
		new_lword = old_lword | LTOSTOP;
		(void) ioctl(STDOUT, TIOCLSET, &new_lword);
#endif
		/* remember that it really is a terminal */
		is_a_terminal = Yes;

		/* send the termcap initialization string */
		putcap(terminal_init);
	}
#endif
	if (tcgetattr(STDOUT, &old_settings) != -1)
	{
		/* copy the settings so we can modify them */
		new_settings = old_settings;

		/* turn off ICANON, character echo and tab expansion */
		new_settings.c_lflag &= ~(ICANON | ECHO);
		new_settings.c_oflag &= ~(TAB3);
		new_settings.c_cc[VMIN] = 1;
		new_settings.c_cc[VTIME] = 0;
		(void) tcsetattr(STDOUT, TCSADRAIN, &new_settings);

		/* remember the erase and kill characters */
		ch_erase = old_settings.c_cc[VERASE];
		ch_kill = old_settings.c_cc[VKILL];

		/* remember that it really is a terminal */
		is_a_terminal = Yes;

		/* send the termcap initialization string */
		putcap(terminal_init);
	}

	if (!is_a_terminal)
	{
		/* not a terminal at all---consider it dumb */
		smart_terminal = No;
	}
}

void
end_screen()
{
	/* move to the lower left, clear the line and send "te" */
	if (smart_terminal)
	{
		putcap(lower_left);
		putcap(clear_line);
		fflush(stdout);
		putcap(terminal_end);
	}

	/* if we have settings to reset, then do so */
	if (is_a_terminal)
	{
#ifdef SGTTY
		(void) ioctl(STDOUT, TIOCSETP, &old_settings);
#ifdef TOStop
		(void) ioctl(STDOUT, TIOCLSET, &old_lword);
#endif
#endif
		(void) tcsetattr(STDOUT, TCSADRAIN, &old_settings);
	}
}

void
reinit_screen()
{
	/* install our settings if it is a terminal */
	if (is_a_terminal)
	{
#ifdef SGTTY
		(void) ioctl(STDOUT, TIOCSETP, &new_settings);
#ifdef TOStop
		(void) ioctl(STDOUT, TIOCLSET, &new_lword);
#endif
#endif
		(void) tcsetattr(STDOUT, TCSADRAIN, &new_settings);
	}

	/* send init string */
	if (smart_terminal)
	{
		putcap(terminal_init);
	}
}

void
standout(char *msg)
{
	if (smart_terminal)
	{
		putcap(start_standout);
		fputs(msg, stdout);
		putcap(end_standout);
	}
	else
	{
		fputs(msg, stdout);
	}
}

void
clear()
{
	if (smart_terminal)
	{
		putcap(clear_screen);
	}
}

int
clear_eol(int len)
{
	if (smart_terminal && !overstrike && len > 0)
	{
		if (clear_line)
		{
			putcap(clear_line);
			return (0);
		}
		else
		{
			while (len-- > 0)
			{
				putchar(' ');
			}
			return (1);
		}
	}
	return (-1);
}

void
go_home()
{
	if (smart_terminal)
	{
		putcap(home);
	}
}