util-linux/more.c

   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 tarball for details.
  15  */
  16
  17 #include "libbb.h"
  18 #if ENABLE_FEATURE_USE_TERMIOS
  19 #include <termios.h>
  20 #endif /* FEATURE_USE_TERMIOS */
  21
  22
  23 #if ENABLE_FEATURE_USE_TERMIOS
  24
  25 struct globals {
  26         int cin_fileno;
  27         struct termios initial_settings;
  28         struct termios new_settings;
  29 };
  30 #define G (*(struct globals*)bb_common_bufsiz1)
  31 //#define G (*ptr_to_globals)
  32 #define initial_settings (G.initial_settings)
  33 #define new_settings     (G.new_settings    )
  34 #define cin_fileno       (G.cin_fileno      )
  35 #define INIT_G() ((void)0)
  36 //#define INIT_G() PTR_TO_GLOBALS = xzalloc(sizeof(G))
  37
  38 #define setTermSettings(fd, argp) tcsetattr(fd, TCSANOW, argp)
  39 #define getTermSettings(fd, argp) tcgetattr(fd, argp)
  40
  41 static void gotsig(int sig)
  42 {
  43         putchar('\n');
  44         setTermSettings(cin_fileno, &initial_settings);
  45         exit(EXIT_FAILURE);
  46 }
  47
  48 #else /* !FEATURE_USE_TERMIOS */
  49 #define INIT_G() ((void)0)
  50 #define setTermSettings(fd, argp) ((void)0)
  51 #endif /* FEATURE_USE_TERMIOS */
  52
  53
  54 int more_main(int argc, char **argv);
  55 int more_main(int argc, char **argv)
  56 {
  57         int c, lines, input = 0;
  58         int please_display_more_prompt = 0;
  59         struct stat st;
  60         FILE *file;
  61         FILE *cin;
  62         int len, page_height;
  63         int terminal_width;
  64         int terminal_height;
  65
  66         INIT_G();
  67
  68         argv++;
  69         /* Another popular pager, most, detects when stdout
  70          * is not a tty and turns into cat. This makes sense. */
  71         if (!isatty(STDOUT_FILENO))
  72                 return bb_cat(argv);
  73         cin = fopen(CURRENT_TTY, "r");
  74         if (!cin)
  75                 return bb_cat(argv);
  76
  77 #if ENABLE_FEATURE_USE_TERMIOS
  78         cin_fileno = fileno(cin);
  79         getTermSettings(cin_fileno, &initial_settings);
  80         new_settings = initial_settings;
  81         new_settings.c_lflag &= ~ICANON;
  82         new_settings.c_lflag &= ~ECHO;
  83         new_settings.c_cc[VMIN] = 1;
  84         new_settings.c_cc[VTIME] = 0;
  85         setTermSettings(cin_fileno, &new_settings);
  86         signal(SIGINT, gotsig);
  87         signal(SIGQUIT, gotsig);
  88         signal(SIGTERM, gotsig);
  89 #endif
  90         please_display_more_prompt = 2;
  91
  92         do {
  93                 file = stdin;
  94                 if (*argv) {
  95                         file = fopen_or_warn(*argv, "r");
  96                         if (!file)
  97                                 continue;
  98                 }
  99                 st.st_size = 0;
 100                 fstat(fileno(file), &st);
 101
 102                 please_display_more_prompt &= ~1;
 103                 /* never returns w, h <= 1 */
 104                 get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
 105                 terminal_width -= 1;
 106                 terminal_height -= 1;
 107
 108                 len = 0;
 109                 lines = 0;
 110                 page_height = terminal_height;
 111                 while ((c = getc(file)) != EOF) {
 112                         if ((please_display_more_prompt & 3) == 3) {
 113                                 len = printf("--More-- ");
 114                                 if (/*file != stdin &&*/ st.st_size > 0) {
 115                                         len += printf("(%d%% of %"OFF_FMT"d bytes)",
 116                                                 (int) (ftello(file)*100 / st.st_size),
 117                                                 st.st_size);
 118                                 }
 119                                 fflush(stdout);
 120
 121                                 /*
 122                                  * We've just displayed the "--More--" prompt, so now we need
 123                                  * to get input from the user.
 124                                  */
 125                                 input = getc(cin);
 126 #if !ENABLE_FEATURE_USE_TERMIOS
 127                                 printf("\033[A"); /* up cursor */
 128 #endif
 129                                 /* Erase the "More" message */
 130                                 printf("\r%*s\r", len, "");
 131                                 len = 0;
 132                                 lines = 0;
 133                                 /* Bottom line on page will become top line
 134                                  * after one page forward. Thus -1: */
 135                                 page_height = terminal_height - 1;
 136                                 please_display_more_prompt &= ~1;
 137
 138                                 if (input == 'q')
 139                                         goto end;
 140                         }
 141
 142                         /*
 143                          * There are two input streams to worry about here:
 144                          *
 145                          * c    : the character we are reading from the file being "mored"
 146                          * input: a character received from the keyboard
 147                          *
 148                          * If we hit a newline in the _file_ stream, we want to test and
 149                          * see if any characters have been hit in the _input_ stream. This
 150                          * allows the user to quit while in the middle of a file.
 151                          */
 152                         if (c == '\n') {
 153                                 /* increment by just one line if we are at
 154                                  * the end of this line */
 155                                 if (input == '\n')
 156                                         please_display_more_prompt |= 1;
 157                                 /* Adjust the terminal height for any overlap, so that
 158                                  * no lines get lost off the top. */
 159                                 if (len >= terminal_width) {
 160                                         int quot, rem;
 161                                         quot = len / terminal_width;
 162                                         rem  = len - (quot * terminal_width);
 163                                         page_height -= (quot - 1);
 164                                         if (rem)
 165                                                 page_height--;
 166                                 }
 167                                 if (++lines >= page_height) {
 168                                         please_display_more_prompt |= 1;
 169                                 }
 170                                 len = 0;
 171                         }
 172                         /*
 173                          * If we just read a newline from the file being 'mored' and any
 174                          * key other than a return is hit, scroll by one page
 175                          */
 176                         putc(c, stdout);
 177                         /* My small mind cannot fathom tabs, backspaces,
 178                          * and UTF-8 */
 179                         len++;
 180                 }
 181                 fclose(file);
 182                 fflush(stdout);
 183         } while (*argv && *++argv);
 184  end:
 185         setTermSettings(cin_fileno, &initial_settings);
 186         return 0;
 187 }