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/* vi: set sw=4 ts=4: */
/*
* Mini more implementation for busybox
*
* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* Latest version blended together by Erik Andersen <andersen@codepoet.org>,
* based on the original more implementation by Bruce, and code from the
* Debian boot-floppies team.
*
* Termios corrects by Vladimir Oleynik <dzo@simtreas.ru>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config MORE
//config: bool "more (6.7 kb)"
//config: default y
//config: help
//config: more is a simple utility which allows you to read text one screen
//config: sized page at a time. If you want to read text that is larger than
//config: the screen, and you are using anything faster than a 300 baud modem,
//config: you will probably find this utility very helpful. If you don't have
//config: any need to reading text files, you can leave this disabled.
//applet:IF_MORE(APPLET(more, BB_DIR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_MORE) += more.o
//usage:#define more_trivial_usage
//usage: "[FILE]..."
//usage:#define more_full_usage "\n\n"
//usage: "View FILE (or stdin) one screenful at a time"
//usage:
//usage:#define more_example_usage
//usage: "$ dmesg | more\n"
#include "libbb.h"
#include "common_bufsiz.h"
struct globals {
int tty_fileno;
unsigned terminal_width;
unsigned terminal_height;
struct termios initial_settings;
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define INIT_G() do { setup_common_bufsiz(); } while (0)
static void get_wh(void)
{
/* never returns w, h <= 1 */
get_terminal_width_height(G.tty_fileno, &G.terminal_width, &G.terminal_height);
G.terminal_height -= 1;
}
static void tcsetattr_tty_TCSANOW(struct termios *settings)
{
tcsetattr(G.tty_fileno, TCSANOW, settings);
}
static void gotsig(int sig UNUSED_PARAM)
{
/* bb_putchar_stderr doesn't use stdio buffering,
* therefore it is safe in signal handler */
bb_putchar_stderr('\n');
tcsetattr_tty_TCSANOW(&G.initial_settings);
_exit(EXIT_FAILURE);
}
#define CONVERTED_TAB_SIZE 8
int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int more_main(int argc UNUSED_PARAM, char **argv)
{
int c = c; /* for compiler */
int input = 0;
int spaces = 0;
int please_display_more_prompt;
FILE *tty;
INIT_G();
/* Parse options */
/* Accepted but ignored: */
/* -d Display help instead of ringing bell */
/* -f Count logical lines (IOW: long lines are not folded) */
/* -l Do not pause after any line containing a ^L (form feed) */
/* -s Squeeze blank lines into one */
/* -u Suppress underlining */
getopt32(argv, "dflsu");
argv += optind;
/* Another popular pager, most, detects when stdout
* is not a tty and turns into cat. This makes sense. */
if (!isatty(STDOUT_FILENO))
return bb_cat(argv);
tty = fopen_for_read(CURRENT_TTY);
if (!tty)
return bb_cat(argv);
G.tty_fileno = fileno(tty);
/* Turn on unbuffered input; turn off echoing */
set_termios_to_raw(G.tty_fileno, &G.initial_settings, 0);
bb_signals(BB_FATAL_SIGS, gotsig);
do {
struct stat st;
FILE *file;
int len;
int lines;
file = stdin;
if (*argv) {
file = fopen_or_warn(*argv, "r");
if (!file)
continue;
}
st.st_size = 0;
fstat(fileno(file), &st);
get_wh();
please_display_more_prompt = 0;
len = 0;
lines = 0;
for (;;) {
int wrap;
if (spaces)
spaces--;
else {
c = getc(file);
if (c == EOF) break;
}
loop_top:
if (input != 'r' && please_display_more_prompt) {
len = printf("--More-- ");
if (st.st_size != 0) {
uoff_t d = (uoff_t)st.st_size / 100;
if (d == 0)
d = 1;
len += printf("(%u%% of %"OFF_FMT"u bytes)",
(int) ((uoff_t)ftello(file) / d),
st.st_size);
}
/*
* We've just displayed the "--More--" prompt, so now we need
* to get input from the user.
*/
for (;;) {
fflush_all();
input = getc(tty);
input = tolower(input);
/* Erase the last message */
printf("\r%*s\r", len, "");
if (input == 'q')
goto end;
/* Due to various multibyte escape
* sequences, it's not ok to accept
* any input as a command to scroll
* the screen. We only allow known
* commands, else we show help msg. */
if (input == ' ' || input == '\n' || input == 'r')
break;
len = printf("(Enter:next line Space:next page Q:quit R:show the rest)");
}
len = 0;
lines = 0;
please_display_more_prompt = 0;
/* The user may have resized the terminal.
* Re-read the dimensions. */
get_wh();
}
/* Crudely convert tabs into spaces, which are
* a bajillion times easier to deal with. */
if (c == '\t') {
spaces = ((unsigned)~len) % CONVERTED_TAB_SIZE;
c = ' ';
}
/*
* There are two input streams to worry about here:
*
* c : the character we are reading from the file being "mored"
* input: a character received from the keyboard
*
* If we hit a newline in the _file_ stream, we want to test and
* see if any characters have been hit in the _input_ stream. This
* allows the user to quit while in the middle of a file.
*/
wrap = (++len > G.terminal_width);
if (c == '\n' || wrap) {
/* Then outputting this character
* will move us to a new line. */
if (++lines >= G.terminal_height || input == '\n')
please_display_more_prompt = 1;
len = 0;
}
if (c != '\n' && wrap) {
/* Then outputting this will also put a character on
* the beginning of that new line. Thus we first want to
* display the prompt (if any), so we skip the putchar()
* and go back to the top of the loop, without reading
* a new character. */
goto loop_top;
}
/* My small mind cannot fathom backspaces and UTF-8 */
putchar(c);
die_if_ferror_stdout(); /* if tty was destroyed (closed xterm, etc) */
}
fclose(file);
fflush_all();
} while (*argv && *++argv);
end:
tcsetattr_tty_TCSANOW(&G.initial_settings);
return 0;
}
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