110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
/*
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* linelength.c: find the terminal line length
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* Preferences: 1. MANWIDTH, 2. COLUMNS, 3. ioctl, 4. 80
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*
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* Originally adapted from Andries Brouwer's man implementation, also
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* released under the GPL: authors believed to include Martin Schulze and
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* Jon Tombs, dated 1995/09/02.
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*
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* Changes for man-db copyright (C) 2001, 2003, 2007 Colin Watson.
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*
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* This file is part of man-db.
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*
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* man-db is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* man-db is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with man-db; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif /* HAVE_CONFIG_H */
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <termios.h>
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#include <unistd.h>
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#include "linelength.h"
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#ifndef _PATH_TTY
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# define _PATH_TTY "/dev/tty"
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#endif /* _PATH_TTY */
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static int line_length = -1;
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int get_line_length (void)
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{
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const char *columns;
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int width;
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#ifdef TIOCGWINSZ
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int dev_tty, tty_fd = -1;
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#endif
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if (line_length != -1)
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return line_length;
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line_length = 80;
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columns = getenv ("MANWIDTH");
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if (columns != NULL) {
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width = atoi (columns);
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if (width > 0)
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return line_length = width;
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}
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columns = getenv ("COLUMNS");
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if (columns != NULL) {
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width = atoi (columns);
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if (width > 0)
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return line_length = width;
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}
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#ifdef TIOCGWINSZ
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/* Original TIOCGWINSZ approach was from Jon Tombs.
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* We don't require both stdin and stdout to be a tty, and line
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* length is primarily a property of output. However, if it happens
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* that stdin is connected to a terminal but stdout isn't, then that
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* may well be because the user is trying something like
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* 'MAN_KEEP_STDERR=1 man foo >/dev/null' to see just the error
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* messages, so use the window size from stdin as a fallback.
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* In some cases we may have neither (e.g. if man is running inside
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* lesspipe); /dev/tty should be a reliable way to get to the
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* current tty if it exists.
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*/
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dev_tty = open (_PATH_TTY, O_RDONLY);
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if (dev_tty >= 0)
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tty_fd = dev_tty;
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else if (isatty (STDOUT_FILENO))
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tty_fd = STDOUT_FILENO;
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else if (isatty (STDIN_FILENO))
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tty_fd = STDIN_FILENO;
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if (tty_fd >= 0) {
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int ret;
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struct winsize wsz;
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ret = ioctl (tty_fd, TIOCGWINSZ, &wsz);
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if (dev_tty >= 0)
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close (dev_tty);
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if (ret)
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perror ("TIOCGWINSZ failed");
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else if (wsz.ws_col)
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return line_length = wsz.ws_col;
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}
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#endif
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return line_length = 80;
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}
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