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.
17 //usage:#define more_trivial_usage
19 //usage:#define more_full_usage "\n\n"
20 //usage: "View FILE (or stdin) one screenful at a time"
22 //usage:#define more_example_usage
23 //usage: "$ dmesg | more\n"
27 /* Support for FEATURE_USE_TERMIOS */
31 struct termios initial_settings;
32 struct termios new_settings;
34 #define G (*(struct globals*)bb_common_bufsiz1)
35 #define INIT_G() ((void)0)
36 #define initial_settings (G.initial_settings)
37 #define new_settings (G.new_settings )
38 #define cin_fileno (G.cin_fileno )
40 #define setTermSettings(fd, argp) \
42 if (ENABLE_FEATURE_USE_TERMIOS) \
43 tcsetattr(fd, TCSANOW, argp); \
45 #define getTermSettings(fd, argp) tcgetattr(fd, argp)
47 static void gotsig(int sig UNUSED_PARAM)
49 /* bb_putchar_stderr doesn't use stdio buffering,
50 * therefore it is safe in signal handler */
51 bb_putchar_stderr('\n');
52 setTermSettings(cin_fileno, &initial_settings);
56 #define CONVERTED_TAB_SIZE 8
58 int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
59 int more_main(int argc UNUSED_PARAM, char **argv)
61 int c = c; /* for compiler */
65 int please_display_more_prompt;
70 unsigned terminal_width;
71 unsigned terminal_height;
76 /* Another popular pager, most, detects when stdout
77 * is not a tty and turns into cat. This makes sense. */
78 if (!isatty(STDOUT_FILENO))
80 cin = fopen_for_read(CURRENT_TTY);
84 if (ENABLE_FEATURE_USE_TERMIOS) {
85 cin_fileno = fileno(cin);
86 getTermSettings(cin_fileno, &initial_settings);
87 new_settings = initial_settings;
88 new_settings.c_lflag &= ~ICANON;
89 new_settings.c_lflag &= ~ECHO;
90 new_settings.c_cc[VMIN] = 1;
91 new_settings.c_cc[VTIME] = 0;
92 setTermSettings(cin_fileno, &new_settings);
103 file = fopen_or_warn(*argv, "r");
108 fstat(fileno(file), &st);
110 please_display_more_prompt = 0;
111 /* never returns w, h <= 1 */
112 get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
113 terminal_height -= 1;
117 while (spaces || (c = getc(file)) != EOF) {
122 if (input != 'r' && please_display_more_prompt) {
123 len = printf("--More-- ");
124 if (st.st_size != 0) {
125 uoff_t d = (uoff_t)st.st_size / 100;
128 len += printf("(%u%% of %"OFF_FMT"u bytes)",
129 (int) ((uoff_t)ftello(file) / d),
135 * We've just displayed the "--More--" prompt, so now we need
136 * to get input from the user.
140 input = tolower(input);
141 if (!ENABLE_FEATURE_USE_TERMIOS)
142 printf("\033[A"); /* cursor up */
143 /* Erase the last message */
144 printf("\r%*s\r", len, "");
146 /* Due to various multibyte escape
147 * sequences, it's not ok to accept
148 * any input as a command to scroll
149 * the screen. We only allow known
150 * commands, else we show help msg. */
151 if (input == ' ' || input == '\n' || input == 'q' || input == 'r')
153 len = printf("(Enter:next line Space:next page Q:quit R:show the rest)");
157 please_display_more_prompt = 0;
162 /* The user may have resized the terminal.
163 * Re-read the dimensions. */
164 if (ENABLE_FEATURE_USE_TERMIOS) {
165 get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height);
166 terminal_height -= 1;
170 /* Crudely convert tabs into spaces, which are
171 * a bajillion times easier to deal with. */
173 spaces = ((unsigned)~len) % CONVERTED_TAB_SIZE;
178 * There are two input streams to worry about here:
180 * c : the character we are reading from the file being "mored"
181 * input: a character received from the keyboard
183 * If we hit a newline in the _file_ stream, we want to test and
184 * see if any characters have been hit in the _input_ stream. This
185 * allows the user to quit while in the middle of a file.
187 wrap = (++len > terminal_width);
188 if (c == '\n' || wrap) {
189 /* Then outputting this character
190 * will move us to a new line. */
191 if (++lines >= terminal_height || input == '\n')
192 please_display_more_prompt = 1;
195 if (c != '\n' && wrap) {
196 /* Then outputting this will also put a character on
197 * the beginning of that new line. Thus we first want to
198 * display the prompt (if any), so we skip the putchar()
199 * and go back to the top of the loop, without reading
200 * a new character. */
203 /* My small mind cannot fathom backspaces and UTF-8 */
205 die_if_ferror_stdout(); /* if tty was destroyed (closed xterm, etc) */
209 } while (*argv && *++argv);
211 setTermSettings(cin_fileno, &initial_settings);