1 /* vi: set sw=4 ts=4: */
3 * Mini more implementation for busybox
5 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
6 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
8 * Latest version blended together by Erik Andersen <andersen@codepoet.org>,
9 * based on the original more implementation by Bruce, and code from the
10 * Debian boot-floppies team.
12 * Termios corrects by Vladimir Oleynik <dzo@simtreas.ru>
14 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
20 //config: more is a simple utility which allows you to read text one screen
21 //config: sized page at a time. If you want to read text that is larger than
22 //config: the screen, and you are using anything faster than a 300 baud modem,
23 //config: you will probably find this utility very helpful. If you don't have
24 //config: any need to reading text files, you can leave this disabled.
26 //applet:IF_MORE(APPLET(more, BB_DIR_BIN, BB_SUID_DROP))
28 //kbuild:lib-$(CONFIG_MORE) += more.o
30 //usage:#define more_trivial_usage
32 //usage:#define more_full_usage "\n\n"
33 //usage: "View FILE (or stdin) one screenful at a time"
35 //usage:#define more_example_usage
36 //usage: "$ dmesg | more\n"
39 #include "common_bufsiz.h"
43 unsigned terminal_width;
44 unsigned terminal_height;
45 struct termios initial_settings;
46 struct termios new_settings;
48 #define G (*(struct globals*)bb_common_bufsiz1)
49 #define INIT_G() do { setup_common_bufsiz(); } while (0)
51 static void get_wh(void)
53 /* never returns w, h <= 1 */
54 get_terminal_width_height(G.tty_fileno, &G.terminal_width, &G.terminal_height);
55 G.terminal_height -= 1;
58 static void tcsetattr_tty_TCSANOW(struct termios *settings)
60 tcsetattr(G.tty_fileno, TCSANOW, settings);
63 static void gotsig(int sig UNUSED_PARAM)
65 /* bb_putchar_stderr doesn't use stdio buffering,
66 * therefore it is safe in signal handler */
67 bb_putchar_stderr('\n');
68 tcsetattr_tty_TCSANOW(&G.initial_settings);
72 #define CONVERTED_TAB_SIZE 8
74 int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
75 int more_main(int argc UNUSED_PARAM, char **argv)
77 int c = c; /* for compiler */
80 int please_display_more_prompt;
86 /* Accepted but ignored: */
87 /* -d Display help instead of ringing bell */
88 /* -f Count logical lines (IOW: long lines are not folded) */
89 /* -l Do not pause after any line containing a ^L (form feed) */
90 /* -s Squeeze blank lines into one */
91 /* -u Suppress underlining */
92 getopt32(argv, "dflsu");
95 /* Another popular pager, most, detects when stdout
96 * is not a tty and turns into cat. This makes sense. */
97 if (!isatty(STDOUT_FILENO))
99 tty = fopen_for_read(CURRENT_TTY);
103 G.tty_fileno = fileno(tty);
104 tcgetattr(G.tty_fileno, &G.initial_settings);
105 G.new_settings = G.initial_settings;
106 G.new_settings.c_lflag &= ~(ICANON | ECHO);
107 G.new_settings.c_cc[VMIN] = 1;
108 G.new_settings.c_cc[VTIME] = 0;
109 tcsetattr_tty_TCSANOW(&G.new_settings);
110 bb_signals(BB_FATAL_SIGS, gotsig);
120 file = fopen_or_warn(*argv, "r");
125 fstat(fileno(file), &st);
129 please_display_more_prompt = 0;
142 if (input != 'r' && please_display_more_prompt) {
143 len = printf("--More-- ");
144 if (st.st_size != 0) {
145 uoff_t d = (uoff_t)st.st_size / 100;
148 len += printf("(%u%% of %"OFF_FMT"u bytes)",
149 (int) ((uoff_t)ftello(file) / d),
154 * We've just displayed the "--More--" prompt, so now we need
155 * to get input from the user.
160 input = tolower(input);
161 /* Erase the last message */
162 printf("\r%*s\r", len, "");
166 /* Due to various multibyte escape
167 * sequences, it's not ok to accept
168 * any input as a command to scroll
169 * the screen. We only allow known
170 * commands, else we show help msg. */
171 if (input == ' ' || input == '\n' || input == 'r')
173 len = printf("(Enter:next line Space:next page Q:quit R:show the rest)");
177 please_display_more_prompt = 0;
179 /* The user may have resized the terminal.
180 * Re-read the dimensions. */
184 /* Crudely convert tabs into spaces, which are
185 * a bajillion times easier to deal with. */
187 spaces = ((unsigned)~len) % CONVERTED_TAB_SIZE;
192 * There are two input streams to worry about here:
194 * c : the character we are reading from the file being "mored"
195 * input: a character received from the keyboard
197 * If we hit a newline in the _file_ stream, we want to test and
198 * see if any characters have been hit in the _input_ stream. This
199 * allows the user to quit while in the middle of a file.
201 wrap = (++len > G.terminal_width);
202 if (c == '\n' || wrap) {
203 /* Then outputting this character
204 * will move us to a new line. */
205 if (++lines >= G.terminal_height || input == '\n')
206 please_display_more_prompt = 1;
209 if (c != '\n' && wrap) {
210 /* Then outputting this will also put a character on
211 * the beginning of that new line. Thus we first want to
212 * display the prompt (if any), so we skip the putchar()
213 * and go back to the top of the loop, without reading
214 * a new character. */
217 /* My small mind cannot fathom backspaces and UTF-8 */
219 die_if_ferror_stdout(); /* if tty was destroyed (closed xterm, etc) */
223 } while (*argv && *++argv);
225 tcsetattr_tty_TCSANOW(&G.initial_settings);