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"
26 #include "common_bufsiz.h"
28 /* Support for FEATURE_USE_TERMIOS */
32 struct termios initial_settings;
33 struct termios new_settings;
35 #define G (*(struct globals*)bb_common_bufsiz1)
36 #define initial_settings (G.initial_settings)
37 #define new_settings (G.new_settings )
38 #define cin_fileno (G.cin_fileno )
39 #define INIT_G() do { setup_common_bufsiz(); } while (0)
41 #define setTermSettings(fd, argp) \
43 if (ENABLE_FEATURE_USE_TERMIOS) \
44 tcsetattr(fd, TCSANOW, argp); \
46 #define getTermSettings(fd, argp) tcgetattr(fd, argp)
48 static void gotsig(int sig UNUSED_PARAM)
50 /* bb_putchar_stderr doesn't use stdio buffering,
51 * therefore it is safe in signal handler */
52 bb_putchar_stderr('\n');
53 setTermSettings(cin_fileno, &initial_settings);
57 #define CONVERTED_TAB_SIZE 8
59 int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
60 int more_main(int argc UNUSED_PARAM, char **argv)
62 int c = c; /* for compiler */
66 int please_display_more_prompt;
71 unsigned terminal_width;
72 unsigned terminal_height;
77 /* Accepted but ignored: */
78 /* -d Display help instead of ringing bell is pressed */
79 /* -f Count logical lines (IOW: long lines are not folded) */
80 /* -l Do not pause after any line containing a ^L (form feed) */
81 /* -s Squeeze blank lines into one */
82 /* -u Suppress underlining */
83 getopt32(argv, "dflsu");
86 /* Another popular pager, most, detects when stdout
87 * is not a tty and turns into cat. This makes sense. */
88 if (!isatty(STDOUT_FILENO))
90 cin = fopen_for_read(CURRENT_TTY);
94 if (ENABLE_FEATURE_USE_TERMIOS) {
95 cin_fileno = fileno(cin);
96 getTermSettings(cin_fileno, &initial_settings);
97 new_settings = initial_settings;
98 new_settings.c_lflag &= ~(ICANON | ECHO);
99 new_settings.c_cc[VMIN] = 1;
100 new_settings.c_cc[VTIME] = 0;
101 setTermSettings(cin_fileno, &new_settings);
112 file = fopen_or_warn(*argv, "r");
117 fstat(fileno(file), &st);
119 please_display_more_prompt = 0;
120 /* never returns w, h <= 1 */
121 get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
122 terminal_height -= 1;
126 while (spaces || (c = getc(file)) != EOF) {
131 if (input != 'r' && please_display_more_prompt) {
132 len = printf("--More-- ");
133 if (st.st_size != 0) {
134 uoff_t d = (uoff_t)st.st_size / 100;
137 len += printf("(%u%% of %"OFF_FMT"u bytes)",
138 (int) ((uoff_t)ftello(file) / d),
144 * We've just displayed the "--More--" prompt, so now we need
145 * to get input from the user.
149 input = tolower(input);
150 if (!ENABLE_FEATURE_USE_TERMIOS)
151 printf("\033[A"); /* cursor up */
152 /* Erase the last message */
153 printf("\r%*s\r", len, "");
155 /* Due to various multibyte escape
156 * sequences, it's not ok to accept
157 * any input as a command to scroll
158 * the screen. We only allow known
159 * commands, else we show help msg. */
160 if (input == ' ' || input == '\n' || input == 'q' || input == 'r')
162 len = printf("(Enter:next line Space:next page Q:quit R:show the rest)");
166 please_display_more_prompt = 0;
171 /* The user may have resized the terminal.
172 * Re-read the dimensions. */
173 if (ENABLE_FEATURE_USE_TERMIOS) {
174 get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height);
175 terminal_height -= 1;
179 /* Crudely convert tabs into spaces, which are
180 * a bajillion times easier to deal with. */
182 spaces = ((unsigned)~len) % CONVERTED_TAB_SIZE;
187 * There are two input streams to worry about here:
189 * c : the character we are reading from the file being "mored"
190 * input: a character received from the keyboard
192 * If we hit a newline in the _file_ stream, we want to test and
193 * see if any characters have been hit in the _input_ stream. This
194 * allows the user to quit while in the middle of a file.
196 wrap = (++len > terminal_width);
197 if (c == '\n' || wrap) {
198 /* Then outputting this character
199 * will move us to a new line. */
200 if (++lines >= terminal_height || input == '\n')
201 please_display_more_prompt = 1;
204 if (c != '\n' && wrap) {
205 /* Then outputting this will also put a character on
206 * the beginning of that new line. Thus we first want to
207 * display the prompt (if any), so we skip the putchar()
208 * and go back to the top of the loop, without reading
209 * a new character. */
212 /* My small mind cannot fathom backspaces and UTF-8 */
214 die_if_ferror_stdout(); /* if tty was destroyed (closed xterm, etc) */
218 } while (*argv && *++argv);
220 setTermSettings(cin_fileno, &initial_settings);