blob: 31e27ab71a8ba76e853a5739cb75d490c01ff2dd
| 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 | //config:config MORE |
| 17 | //config: bool "more" |
| 18 | //config: default y |
| 19 | //config: help |
| 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. |
| 25 | |
| 26 | //applet:IF_MORE(APPLET(more, BB_DIR_BIN, BB_SUID_DROP)) |
| 27 | |
| 28 | //kbuild:lib-$(CONFIG_MORE) += more.o |
| 29 | |
| 30 | //usage:#define more_trivial_usage |
| 31 | //usage: "[FILE]..." |
| 32 | //usage:#define more_full_usage "\n\n" |
| 33 | //usage: "View FILE (or stdin) one screenful at a time" |
| 34 | //usage: |
| 35 | //usage:#define more_example_usage |
| 36 | //usage: "$ dmesg | more\n" |
| 37 | |
| 38 | #include "libbb.h" |
| 39 | #include "common_bufsiz.h" |
| 40 | |
| 41 | /* Support for FEATURE_USE_TERMIOS */ |
| 42 | |
| 43 | struct globals { |
| 44 | int cin_fileno; |
| 45 | struct termios initial_settings; |
| 46 | struct termios new_settings; |
| 47 | } FIX_ALIASING; |
| 48 | #define G (*(struct globals*)bb_common_bufsiz1) |
| 49 | #define initial_settings (G.initial_settings) |
| 50 | #define new_settings (G.new_settings ) |
| 51 | #define cin_fileno (G.cin_fileno ) |
| 52 | #define INIT_G() do { setup_common_bufsiz(); } while (0) |
| 53 | |
| 54 | #define setTermSettings(fd, argp) \ |
| 55 | do { \ |
| 56 | if (ENABLE_FEATURE_USE_TERMIOS) \ |
| 57 | tcsetattr(fd, TCSANOW, argp); \ |
| 58 | } while (0) |
| 59 | #define getTermSettings(fd, argp) tcgetattr(fd, argp) |
| 60 | |
| 61 | static void gotsig(int sig UNUSED_PARAM) |
| 62 | { |
| 63 | /* bb_putchar_stderr doesn't use stdio buffering, |
| 64 | * therefore it is safe in signal handler */ |
| 65 | bb_putchar_stderr('\n'); |
| 66 | setTermSettings(cin_fileno, &initial_settings); |
| 67 | _exit(EXIT_FAILURE); |
| 68 | } |
| 69 | |
| 70 | #define CONVERTED_TAB_SIZE 8 |
| 71 | |
| 72 | int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| 73 | int more_main(int argc UNUSED_PARAM, char **argv) |
| 74 | { |
| 75 | int c = EOF; /* for compiler */ |
| 76 | int input = 0; |
| 77 | int spaces = 0; |
| 78 | int please_display_more_prompt; |
| 79 | struct stat st; |
| 80 | FILE *file; |
| 81 | FILE *cin; |
| 82 | unsigned len, lines; |
| 83 | unsigned terminal_width; |
| 84 | unsigned terminal_height; |
| 85 | |
| 86 | INIT_G(); |
| 87 | |
| 88 | /* Parse options */ |
| 89 | /* Accepted but ignored: */ |
| 90 | /* -d Display help instead of ringing bell is pressed */ |
| 91 | /* -f Count logical lines (IOW: long lines are not folded) */ |
| 92 | /* -l Do not pause after any line containing a ^L (form feed) */ |
| 93 | /* -s Squeeze blank lines into one */ |
| 94 | /* -u Suppress underlining */ |
| 95 | getopt32(argv, "dflsu"); |
| 96 | argv += optind; |
| 97 | |
| 98 | /* Another popular pager, most, detects when stdout |
| 99 | * is not a tty and turns into cat. This makes sense. */ |
| 100 | if (!isatty(STDOUT_FILENO)) |
| 101 | return bb_cat(argv); |
| 102 | cin = fopen_for_read(CURRENT_TTY); |
| 103 | if (!cin) |
| 104 | return bb_cat(argv); |
| 105 | |
| 106 | if (ENABLE_FEATURE_USE_TERMIOS) { |
| 107 | cin_fileno = fileno(cin); |
| 108 | getTermSettings(cin_fileno, &initial_settings); |
| 109 | new_settings = initial_settings; |
| 110 | new_settings.c_lflag &= ~(ICANON | ECHO); |
| 111 | new_settings.c_cc[VMIN] = 1; |
| 112 | new_settings.c_cc[VTIME] = 0; |
| 113 | setTermSettings(cin_fileno, &new_settings); |
| 114 | bb_signals(0 |
| 115 | + (1 << SIGINT) |
| 116 | + (1 << SIGQUIT) |
| 117 | + (1 << SIGTERM) |
| 118 | , gotsig); |
| 119 | } |
| 120 | |
| 121 | do { |
| 122 | file = stdin; |
| 123 | if (*argv) { |
| 124 | file = fopen_or_warn(*argv, "r"); |
| 125 | if (!file) |
| 126 | continue; |
| 127 | } |
| 128 | st.st_size = 0; |
| 129 | fstat(fileno(file), &st); |
| 130 | |
| 131 | please_display_more_prompt = 0; |
| 132 | /* never returns w, h <= 1 */ |
| 133 | get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height); |
| 134 | terminal_height -= 1; |
| 135 | |
| 136 | len = 0; |
| 137 | lines = 0; |
| 138 | while (spaces || (c = getc(file)) != EOF) { |
| 139 | int wrap; |
| 140 | if (spaces) |
| 141 | spaces--; |
| 142 | loop_top: |
| 143 | if (input != 'r' && please_display_more_prompt) { |
| 144 | len = printf("--More-- "); |
| 145 | if (st.st_size != 0) { |
| 146 | len += printf("(%u%% of %"FILESIZE_FMT"u bytes)", |
| 147 | (int) (ftello(file)*100 / st.st_size), |
| 148 | st.st_size); |
| 149 | } |
| 150 | fflush_all(); |
| 151 | |
| 152 | /* |
| 153 | * We've just displayed the "--More--" prompt, so now we need |
| 154 | * to get input from the user. |
| 155 | */ |
| 156 | for (;;) { |
| 157 | input = getc(cin); |
| 158 | input = tolower(input); |
| 159 | if (!ENABLE_FEATURE_USE_TERMIOS) |
| 160 | printf("\033[A"); /* cursor up */ |
| 161 | /* Erase the last message */ |
| 162 | printf("\r%*s\r", len, ""); |
| 163 | |
| 164 | /* Due to various multibyte escape |
| 165 | * sequences, it's not ok to accept |
| 166 | * any input as a command to scroll |
| 167 | * the screen. We only allow known |
| 168 | * commands, else we show help msg. */ |
| 169 | if (input == ' ' || input == '\n' || input == 'q' || input == 'r') |
| 170 | break; |
| 171 | len = printf("(Enter:next line Space:next page Q:quit R:show the rest)"); |
| 172 | } |
| 173 | len = 0; |
| 174 | lines = 0; |
| 175 | please_display_more_prompt = 0; |
| 176 | |
| 177 | if (input == 'q') |
| 178 | goto end; |
| 179 | |
| 180 | /* The user may have resized the terminal. |
| 181 | * Re-read the dimensions. */ |
| 182 | if (ENABLE_FEATURE_USE_TERMIOS) { |
| 183 | get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height); |
| 184 | terminal_height -= 1; |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | /* Crudely convert tabs into spaces, which are |
| 189 | * a bajillion times easier to deal with. */ |
| 190 | if (c == '\t') { |
| 191 | spaces = ((unsigned)~len) % CONVERTED_TAB_SIZE; |
| 192 | c = ' '; |
| 193 | } |
| 194 | |
| 195 | /* |
| 196 | * There are two input streams to worry about here: |
| 197 | * |
| 198 | * c : the character we are reading from the file being "mored" |
| 199 | * input: a character received from the keyboard |
| 200 | * |
| 201 | * If we hit a newline in the _file_ stream, we want to test and |
| 202 | * see if any characters have been hit in the _input_ stream. This |
| 203 | * allows the user to quit while in the middle of a file. |
| 204 | */ |
| 205 | wrap = (++len > terminal_width); |
| 206 | if (c == '\n' || wrap) { |
| 207 | /* Then outputting this character |
| 208 | * will move us to a new line. */ |
| 209 | if (++lines >= terminal_height || input == '\n') |
| 210 | please_display_more_prompt = 1; |
| 211 | len = 0; |
| 212 | } |
| 213 | if (c != '\n' && wrap) { |
| 214 | /* Then outputting this will also put a character on |
| 215 | * the beginning of that new line. Thus we first want to |
| 216 | * display the prompt (if any), so we skip the putchar() |
| 217 | * and go back to the top of the loop, without reading |
| 218 | * a new character. */ |
| 219 | goto loop_top; |
| 220 | } |
| 221 | /* My small mind cannot fathom backspaces and UTF-8 */ |
| 222 | putchar(c); |
| 223 | die_if_ferror_stdout(); /* if tty was destroyed (closed xterm, etc) */ |
| 224 | } |
| 225 | fclose(file); |
| 226 | fflush_all(); |
| 227 | } while (*argv && *++argv); |
| 228 | end: |
| 229 | setTermSettings(cin_fileno, &initial_settings); |
| 230 | return 0; |
| 231 | } |
| 232 |