blob: 04ad2d1a31c7e4b10169278c01dfd3b45a370bbe
| 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * Mini more implementation for busybox |
| 4 | * |
| 5 | * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>. |
| 6 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
| 7 | * |
| 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. |
| 11 | * |
| 12 | * Termios corrects by Vladimir Oleynik <dzo@simtreas.ru> |
| 13 | * |
| 14 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| 15 | */ |
| 16 | |
| 17 | //usage:#define more_trivial_usage |
| 18 | //usage: "[FILE]..." |
| 19 | //usage:#define more_full_usage "\n\n" |
| 20 | //usage: "View FILE (or stdin) one screenful at a time" |
| 21 | //usage: |
| 22 | //usage:#define more_example_usage |
| 23 | //usage: "$ dmesg | more\n" |
| 24 | |
| 25 | #include "libbb.h" |
| 26 | |
| 27 | /* Support for FEATURE_USE_TERMIOS */ |
| 28 | |
| 29 | struct globals { |
| 30 | int cin_fileno; |
| 31 | struct termios initial_settings; |
| 32 | struct termios new_settings; |
| 33 | } FIX_ALIASING; |
| 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 ) |
| 39 | |
| 40 | #define setTermSettings(fd, argp) \ |
| 41 | do { \ |
| 42 | if (ENABLE_FEATURE_USE_TERMIOS) \ |
| 43 | tcsetattr(fd, TCSANOW, argp); \ |
| 44 | } while (0) |
| 45 | #define getTermSettings(fd, argp) tcgetattr(fd, argp) |
| 46 | |
| 47 | static void gotsig(int sig UNUSED_PARAM) |
| 48 | { |
| 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); |
| 53 | _exit(EXIT_FAILURE); |
| 54 | } |
| 55 | |
| 56 | #define CONVERTED_TAB_SIZE 8 |
| 57 | |
| 58 | int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| 59 | int more_main(int argc UNUSED_PARAM, char **argv) |
| 60 | { |
| 61 | int c = EOF; /* for compiler */ |
| 62 | int input = 0; |
| 63 | int spaces = 0; |
| 64 | int please_display_more_prompt; |
| 65 | struct stat st; |
| 66 | FILE *file; |
| 67 | FILE *cin; |
| 68 | unsigned len, lines; |
| 69 | unsigned terminal_width; |
| 70 | unsigned terminal_height; |
| 71 | |
| 72 | INIT_G(); |
| 73 | |
| 74 | argv++; |
| 75 | /* Another popular pager, most, detects when stdout |
| 76 | * is not a tty and turns into cat. This makes sense. */ |
| 77 | if (!isatty(STDOUT_FILENO)) |
| 78 | return bb_cat(argv); |
| 79 | cin = fopen_for_read(CURRENT_TTY); |
| 80 | if (!cin) |
| 81 | return bb_cat(argv); |
| 82 | |
| 83 | if (ENABLE_FEATURE_USE_TERMIOS) { |
| 84 | cin_fileno = fileno(cin); |
| 85 | getTermSettings(cin_fileno, &initial_settings); |
| 86 | new_settings = initial_settings; |
| 87 | new_settings.c_lflag &= ~(ICANON | ECHO); |
| 88 | new_settings.c_cc[VMIN] = 1; |
| 89 | new_settings.c_cc[VTIME] = 0; |
| 90 | setTermSettings(cin_fileno, &new_settings); |
| 91 | bb_signals(0 |
| 92 | + (1 << SIGINT) |
| 93 | + (1 << SIGQUIT) |
| 94 | + (1 << SIGTERM) |
| 95 | , gotsig); |
| 96 | } |
| 97 | |
| 98 | do { |
| 99 | file = stdin; |
| 100 | if (*argv) { |
| 101 | file = fopen_or_warn(*argv, "r"); |
| 102 | if (!file) |
| 103 | continue; |
| 104 | } |
| 105 | st.st_size = 0; |
| 106 | fstat(fileno(file), &st); |
| 107 | |
| 108 | please_display_more_prompt = 0; |
| 109 | /* never returns w, h <= 1 */ |
| 110 | get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height); |
| 111 | terminal_height -= 1; |
| 112 | |
| 113 | len = 0; |
| 114 | lines = 0; |
| 115 | while (spaces || (c = getc(file)) != EOF) { |
| 116 | int wrap; |
| 117 | if (spaces) |
| 118 | spaces--; |
| 119 | loop_top: |
| 120 | if (input != 'r' && please_display_more_prompt) { |
| 121 | len = printf("--More-- "); |
| 122 | if (st.st_size != 0) { |
| 123 | len += printf("(%u%% of %"FILESIZE_FMT"u bytes)", |
| 124 | (int) (ftello(file)*100 / st.st_size), |
| 125 | st.st_size); |
| 126 | } |
| 127 | fflush_all(); |
| 128 | |
| 129 | /* |
| 130 | * We've just displayed the "--More--" prompt, so now we need |
| 131 | * to get input from the user. |
| 132 | */ |
| 133 | for (;;) { |
| 134 | input = getc(cin); |
| 135 | input = tolower(input); |
| 136 | if (!ENABLE_FEATURE_USE_TERMIOS) |
| 137 | printf("\033[A"); /* cursor up */ |
| 138 | /* Erase the last message */ |
| 139 | printf("\r%*s\r", len, ""); |
| 140 | |
| 141 | /* Due to various multibyte escape |
| 142 | * sequences, it's not ok to accept |
| 143 | * any input as a command to scroll |
| 144 | * the screen. We only allow known |
| 145 | * commands, else we show help msg. */ |
| 146 | if (input == ' ' || input == '\n' || input == 'q' || input == 'r') |
| 147 | break; |
| 148 | len = printf("(Enter:next line Space:next page Q:quit R:show the rest)"); |
| 149 | } |
| 150 | len = 0; |
| 151 | lines = 0; |
| 152 | please_display_more_prompt = 0; |
| 153 | |
| 154 | if (input == 'q') |
| 155 | goto end; |
| 156 | |
| 157 | /* The user may have resized the terminal. |
| 158 | * Re-read the dimensions. */ |
| 159 | if (ENABLE_FEATURE_USE_TERMIOS) { |
| 160 | get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height); |
| 161 | terminal_height -= 1; |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | /* Crudely convert tabs into spaces, which are |
| 166 | * a bajillion times easier to deal with. */ |
| 167 | if (c == '\t') { |
| 168 | spaces = ((unsigned)~len) % CONVERTED_TAB_SIZE; |
| 169 | c = ' '; |
| 170 | } |
| 171 | |
| 172 | /* |
| 173 | * There are two input streams to worry about here: |
| 174 | * |
| 175 | * c : the character we are reading from the file being "mored" |
| 176 | * input: a character received from the keyboard |
| 177 | * |
| 178 | * If we hit a newline in the _file_ stream, we want to test and |
| 179 | * see if any characters have been hit in the _input_ stream. This |
| 180 | * allows the user to quit while in the middle of a file. |
| 181 | */ |
| 182 | wrap = (++len > terminal_width); |
| 183 | if (c == '\n' || wrap) { |
| 184 | /* Then outputting this character |
| 185 | * will move us to a new line. */ |
| 186 | if (++lines >= terminal_height || input == '\n') |
| 187 | please_display_more_prompt = 1; |
| 188 | len = 0; |
| 189 | } |
| 190 | if (c != '\n' && wrap) { |
| 191 | /* Then outputting this will also put a character on |
| 192 | * the beginning of that new line. Thus we first want to |
| 193 | * display the prompt (if any), so we skip the putchar() |
| 194 | * and go back to the top of the loop, without reading |
| 195 | * a new character. */ |
| 196 | goto loop_top; |
| 197 | } |
| 198 | /* My small mind cannot fathom backspaces and UTF-8 */ |
| 199 | putchar(c); |
| 200 | die_if_ferror_stdout(); /* if tty was destroyed (closed xterm, etc) */ |
| 201 | } |
| 202 | fclose(file); |
| 203 | fflush_all(); |
| 204 | } while (*argv && *++argv); |
| 205 | end: |
| 206 | setTermSettings(cin_fileno, &initial_settings); |
| 207 | return 0; |
| 208 | } |
| 209 |