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 "busybox.h"
  18
  19
  20 #if ENABLE_FEATURE_USE_TERMIOS
  21 static int cin_fileno;
  22 #include <termios.h>
  23 #define setTermSettings(fd, argp) tcsetattr(fd, TCSANOW, argp)
  24 #define getTermSettings(fd, argp) tcgetattr(fd, argp);
  25
  26 static struct termios initial_settings, new_settings;
  27
  28 static void set_tty_to_initial_mode(void)
  29 {
  30         setTermSettings(cin_fileno, &initial_settings);
  31 }
  32
  33 static void gotsig(int sig)
  34 {
  35         putchar('\n');
  36         exit(EXIT_FAILURE);
  37 }
  38 #endif /* FEATURE_USE_TERMIOS */
  39
  40
  41 int more_main(int argc, char **argv)
  42 {
  43         int c, lines, input = 0;
  44         int please_display_more_prompt = 0;
  45         struct stat st;
  46         FILE *file;
  47         FILE *cin;
  48         int len, page_height;
  49         int terminal_width;
  50         int terminal_height;
  51
  52         argc--;
  53         argv++;
  54
  55         cin = stdin;
  56         /* use input from terminal unless we do "more >outfile" */
  57         if (isatty(STDOUT_FILENO)) {
  58                 cin = fopen(CURRENT_TTY, "r");
  59                 if (!cin)
  60                         cin = xfopen(CONSOLE_DEV, "r");
  61                 please_display_more_prompt = 2;
  62 #if ENABLE_FEATURE_USE_TERMIOS
  63                 cin_fileno = fileno(cin);
  64                 getTermSettings(cin_fileno, &initial_settings);
  65                 new_settings = initial_settings;
  66                 new_settings.c_lflag &= ~ICANON;
  67                 new_settings.c_lflag &= ~ECHO;
  68                 new_settings.c_cc[VMIN] = 1;
  69                 new_settings.c_cc[VTIME] = 0;
  70                 setTermSettings(cin_fileno, &new_settings);
  71                 atexit(set_tty_to_initial_mode);
  72                 signal(SIGINT, gotsig);
  73                 signal(SIGQUIT, gotsig);
  74                 signal(SIGTERM, gotsig);
  75 #endif
  76         }
  77
  78         do {
  79                 file = stdin;
  80                 if (argc != 0) {
  81                         file = fopen_or_warn(*argv, "r");
  82                         if (!file)
  83                                 goto loop;
  84                 }
  85
  86                 st.st_size = 0;
  87                 fstat(fileno(file), &st);
  88
  89                 please_display_more_prompt &= ~1;
  90
  91                 get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
  92                 if (terminal_height > 4)
  93                         terminal_height -= 2;
  94                 if (terminal_width > 0)
  95                         terminal_width -= 1;
  96
  97                 len = 0;
  98                 lines = 0;
  99                 page_height = terminal_height;
 100                 while ((c = getc(file)) != EOF) {
 101
 102                         if ((please_display_more_prompt & 3) == 3) {
 103                                 len = printf("--More-- ");
 104                                 if (file != stdin && st.st_size > 0) {
 105                                         len += printf("(%d%% of %"OFF_FMT"d bytes)",
 106                                                 (int) (ftello(file)*100 / st.st_size),
 107                                                 st.st_size);
 108                                 }
 109                                 fflush(stdout);
 110
 111                                 /*
 112                                  * We've just displayed the "--More--" prompt, so now we need
 113                                  * to get input from the user.
 114                                  */
 115                                 input = getc(cin);
 116 #if !ENABLE_FEATURE_USE_TERMIOS
 117                                 printf("\033[A"); /* up cursor */
 118 #endif
 119                                 /* Erase the "More" message */
 120                                 printf("\r%*s\r", len, "");
 121                                 len = 0;
 122                                 lines = 0;
 123                                 page_height = terminal_height;
 124                                 please_display_more_prompt &= ~1;
 125
 126                                 if (input == 'q')
 127                                         goto end;
 128                         }
 129
 130                         /*
 131                          * There are two input streams to worry about here:
 132                          *
 133                          * c     : the character we are reading from the file being "mored"
 134                          * input : a character received from the keyboard
 135                          *
 136                          * If we hit a newline in the _file_ stream, we want to test and
 137                          * see if any characters have been hit in the _input_ stream. This
 138                          * allows the user to quit while in the middle of a file.
 139                          */
 140                         if (c == '\n') {
 141                                 /* increment by just one line if we are at
 142                                  * the end of this line */
 143                                 if (input == '\n')
 144                                         please_display_more_prompt |= 1;
 145                                 /* Adjust the terminal height for any overlap, so that
 146                                  * no lines get lost off the top. */
 147                                 if (len >= terminal_width) {
 148                                         int quot, rem;
 149                                         quot = len / terminal_width;
 150                                         rem  = len - (quot * terminal_width);
 151                                         if (quot) {
 152                                                 if (rem)
 153                                                         page_height -= quot;
 154                                                 else
 155                                                         page_height -= (quot - 1);
 156                                         }
 157                                 }
 158                                 if (++lines >= page_height) {
 159                                         please_display_more_prompt |= 1;
 160                                 }
 161                                 len = 0;
 162                         }
 163                         /*
 164                          * If we just read a newline from the file being 'mored' and any
 165                          * key other than a return is hit, scroll by one page
 166                          */
 167                         putc(c, stdout);
 168                         len++;
 169                 }
 170                 fclose(file);
 171                 fflush(stdout);
 172  loop:
 173                 argv++;
 174         } while (--argc > 0);
 175  end:
 176         return 0;
 177 }