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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.
*/
//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"
/* Support for FEATURE_USE_TERMIOS */
struct globals {
int cin_fileno;
struct termios initial_settings;
struct termios new_settings;
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define INIT_G() ((void)0)
#define initial_settings (G.initial_settings)
#define new_settings (G.new_settings )
#define cin_fileno (G.cin_fileno )
#define setTermSettings(fd, argp) \
do { \
if (ENABLE_FEATURE_USE_TERMIOS) \
tcsetattr(fd, TCSANOW, argp); \
} while (0)
#define getTermSettings(fd, argp) tcgetattr(fd, argp)
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');
setTermSettings(cin_fileno, &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 lines;
int input = 0;
int spaces = 0;
int please_display_more_prompt;
struct stat st;
FILE *file;
FILE *cin;
int len;
unsigned terminal_width;
unsigned terminal_height;
INIT_G();
argv++;
/* 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);
cin = fopen_for_read(CURRENT_TTY);
if (!cin)
return bb_cat(argv);
if (ENABLE_FEATURE_USE_TERMIOS) {
cin_fileno = fileno(cin);
getTermSettings(cin_fileno, &initial_settings);
new_settings = initial_settings;
new_settings.c_lflag &= ~(ICANON | ECHO);
new_settings.c_cc[VMIN] = 1;
new_settings.c_cc[VTIME] = 0;
setTermSettings(cin_fileno, &new_settings);
bb_signals(0
+ (1 << SIGINT)
+ (1 << SIGQUIT)
+ (1 << SIGTERM)
, gotsig);
}
do {
file = stdin;
if (*argv) {
file = fopen_or_warn(*argv, "r");
if (!file)
continue;
}
st.st_size = 0;
fstat(fileno(file), &st);
please_display_more_prompt = 0;
/* never returns w, h <= 1 */
get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
terminal_height -= 1;
len = 0;
lines = 0;
while (spaces || (c = getc(file)) != EOF) {
int wrap;
if (spaces)
spaces--;
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);
}
fflush_all();
/*
* We've just displayed the "--More--" prompt, so now we need
* to get input from the user.
*/
for (;;) {
input = getc(cin);
input = tolower(input);
if (!ENABLE_FEATURE_USE_TERMIOS)
printf("\033[A"); /* cursor up */
/* Erase the last message */
printf("\r%*s\r", len, "");
/* 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 == 'q' || 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;
if (input == 'q')
goto end;
/* The user may have resized the terminal.
* Re-read the dimensions. */
if (ENABLE_FEATURE_USE_TERMIOS) {
get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height);
terminal_height -= 1;
}
}
/* 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 > terminal_width);
if (c == '\n' || wrap) {
/* Then outputting this character
* will move us to a new line. */
if (++lines >= 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:
setTermSettings(cin_fileno, &initial_settings);
return 0;
}
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