*: introduce and use bb_unsetenv_and_free
[oweals/busybox.git] / util-linux / more.c
index 2a38ef326762760c19f0fca86f4f53bdc3c821c8..55694e434936cb097fd958efe6632a3163d4aca7 100644 (file)
  * Licensed under GPLv2 or later, see file License in this tarball for details.
  */
 
-#include "busybox.h"
-
-
-#if ENABLE_FEATURE_USE_TERMIOS
-static int cin_fileno;
-#include <termios.h>
-#define setTermSettings(fd, argp) tcsetattr(fd, TCSANOW, argp)
-#define getTermSettings(fd, argp) tcgetattr(fd, argp);
-
-static struct termios initial_settings, new_settings;
-
-static void set_tty_to_initial_mode(void)
+#include "libbb.h"
+
+/* Support for FEATURE_USE_TERMIOS */
+
+struct globals {
+       int cin_fileno;
+       struct termios initial_settings;
+       struct termios new_settings;
+} FIX_ALIASING;
+#define G (*(struct globals*)bb_common_bufsiz1)
+#define INIT_G() ((void)0)
+#define initial_settings (G.initial_settings)
+#define new_settings     (G.new_settings    )
+#define cin_fileno       (G.cin_fileno      )
+
+#define setTermSettings(fd, argp) do { \
+               if (ENABLE_FEATURE_USE_TERMIOS) tcsetattr(fd, TCSANOW, argp); \
+       } while(0)
+#define getTermSettings(fd, argp) tcgetattr(fd, argp)
+
+static void gotsig(int sig UNUSED_PARAM)
 {
+       bb_putchar('\n');
        setTermSettings(cin_fileno, &initial_settings);
-}
-
-static void gotsig(int sig)
-{
-       putchar('\n');
        exit(EXIT_FAILURE);
 }
-#endif /* FEATURE_USE_TERMIOS */
 
+#define CONVERTED_TAB_SIZE 8
 
-int more_main(int argc, char **argv);
-int more_main(int argc, char **argv)
+int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int more_main(int argc UNUSED_PARAM, char **argv)
 {
-       int c, lines, input = 0;
-       int please_display_more_prompt = 0;
+       int c = c; /* for gcc */
+       int lines;
+       int input = 0;
+       int spaces = 0;
+       int please_display_more_prompt;
        struct stat st;
        FILE *file;
        FILE *cin;
-       int len, page_height;
-       int terminal_width;
-       int terminal_height;
+       int len;
+       unsigned terminal_width;
+       unsigned terminal_height;
+
+       INIT_G();
 
        argv++;
        /* Another popular pager, most, detects when stdout
         * is not a tty and turns into cat. This makes sense. */
        if (!isatty(STDOUT_FILENO))
                return bb_cat(argv);
-       cin = fopen(CURRENT_TTY, "r");
+       cin = fopen_for_read(CURRENT_TTY);
        if (!cin)
                return bb_cat(argv);
 
-#if ENABLE_FEATURE_USE_TERMIOS
-       cin_fileno = fileno(cin);
-       getTermSettings(cin_fileno, &initial_settings);
-       new_settings = initial_settings;
-       new_settings.c_lflag &= ~ICANON;
-       new_settings.c_lflag &= ~ECHO;
-       new_settings.c_cc[VMIN] = 1;
-       new_settings.c_cc[VTIME] = 0;
-       setTermSettings(cin_fileno, &new_settings);
-       atexit(set_tty_to_initial_mode);
-       signal(SIGINT, gotsig);
-       signal(SIGQUIT, gotsig);
-       signal(SIGTERM, gotsig);
-#endif
-       please_display_more_prompt = 2;
+       if (ENABLE_FEATURE_USE_TERMIOS) {
+               cin_fileno = fileno(cin);
+               getTermSettings(cin_fileno, &initial_settings);
+               new_settings = initial_settings;
+               new_settings.c_lflag &= ~ICANON;
+               new_settings.c_lflag &= ~ECHO;
+               new_settings.c_cc[VMIN] = 1;
+               new_settings.c_cc[VTIME] = 0;
+               setTermSettings(cin_fileno, &new_settings);
+               bb_signals(0
+                       + (1 << SIGINT)
+                       + (1 << SIGQUIT)
+                       + (1 << SIGTERM)
+                       , gotsig);
+       }
 
        do {
                file = stdin;
@@ -85,89 +95,103 @@ int more_main(int argc, char **argv)
                st.st_size = 0;
                fstat(fileno(file), &st);
 
-               please_display_more_prompt &= ~1;
+               please_display_more_prompt = 0;
                /* never returns w, h <= 1 */
                get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
-               terminal_width -= 1;
                terminal_height -= 1;
 
                len = 0;
                lines = 0;
-               page_height = terminal_height;
-               while ((c = getc(file)) != EOF) {
-
-                       if ((please_display_more_prompt & 3) == 3) {
+               while (spaces || (c = getc(file)) != EOF) {
+                       int wrap;
+                       if (spaces)
+                               spaces--;
+ loop_top:
+                       if (input != 'r' && please_display_more_prompt) {
                                len = printf("--More-- ");
-                               if (/*file != stdin &&*/ st.st_size > 0) {
-                                       len += printf("(%d%% of %"OFF_FMT"d bytes)",
+                               if (st.st_size > 0) {
+                                       len += printf("(%u%% of %"OFF_FMT"u bytes)",
                                                (int) (ftello(file)*100 / st.st_size),
                                                st.st_size);
                                }
-                               fflush(stdout);
+                               fflush_all();
 
                                /*
                                 * We've just displayed the "--More--" prompt, so now we need
                                 * to get input from the user.
                                 */
-                               input = getc(cin);
-#if !ENABLE_FEATURE_USE_TERMIOS
-                               printf("\033[A"); /* up cursor */
-#endif
-                               /* Erase the "More" message */
-                               printf("\r%*s\r", len, "");
+                               for (;;) {
+                                       input = getc(cin);
+                                       input = tolower(input);
+                                       if (!ENABLE_FEATURE_USE_TERMIOS)
+                                               printf("\033[A"); /* cursor up */
+                                       /* Erase the last message */
+                                       printf("\r%*s\r", len, "");
+
+                                       /* Due to various multibyte escape
+                                        * sequences, it's not ok to accept
+                                        * any input as a command to scroll
+                                        * the screen. We only allow known
+                                        * commands, else we show help msg. */
+                                       if (input == ' ' || input == '\n' || input == 'q' || input == 'r')
+                                               break;
+                                       len = printf("(Enter:next line Space:next page Q:quit R:show the rest)");
+                               }
                                len = 0;
                                lines = 0;
-                               /* Bottom line on page will become top line
-                                * after one page forward. Thus -1: */
-                               page_height = terminal_height - 1;
-                               please_display_more_prompt &= ~1;
+                               please_display_more_prompt = 0;
 
                                if (input == 'q')
                                        goto end;
+
+                               /* The user may have resized the terminal.
+                                * Re-read the dimensions. */
+                               if (ENABLE_FEATURE_USE_TERMIOS) {
+                                       get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height);
+                                       terminal_height -= 1;
+                               }
+                       }
+
+                       /* Crudely convert tabs into spaces, which are
+                        * a bajillion times easier to deal with. */
+                       if (c == '\t') {
+                               spaces = CONVERTED_TAB_SIZE - 1;
+                               c = ' ';
                        }
 
                        /*
                         * There are two input streams to worry about here:
                         *
-                        * c     : the character we are reading from the file being "mored"
-                        * input : a character received from the keyboard
+                        * c    : the character we are reading from the file being "mored"
+                        * input: a character received from the keyboard
                         *
                         * If we hit a newline in the _file_ stream, we want to test and
                         * see if any characters have been hit in the _input_ stream. This
                         * allows the user to quit while in the middle of a file.
                         */
-                       if (c == '\n') {
-                               /* increment by just one line if we are at
-                                * the end of this line */
-                               if (input == '\n')
-                                       please_display_more_prompt |= 1;
-                               /* Adjust the terminal height for any overlap, so that
-                                * no lines get lost off the top. */
-                               if (len >= terminal_width) {
-                                       int quot, rem;
-                                       quot = len / terminal_width;
-                                       rem  = len - (quot * terminal_width);
-                                       page_height -= (quot - 1);
-                                       if (rem)
-                                               page_height--;
-                               }
-                               if (++lines >= page_height) {
-                                       please_display_more_prompt |= 1;
-                               }
+                       wrap = (++len > terminal_width);
+                       if (c == '\n' || wrap) {
+                               /* Then outputting this character
+                                * will move us to a new line. */
+                               if (++lines >= terminal_height || input == '\n')
+                                       please_display_more_prompt = 1;
                                len = 0;
                        }
-                       /*
-                        * If we just read a newline from the file being 'mored' and any
-                        * key other than a return is hit, scroll by one page
-                        */
-                       putc(c, stdout);
-                       /* My small mind cannot fathom tabs, backspaces,
-                        * and UTF-8 */
-                       len++;
+                       if (c != '\n' && wrap) {
+                               /* Then outputting this will also put a character on
+                                * the beginning of that new line. Thus we first want to
+                                * display the prompt (if any), so we skip the putchar()
+                                * and go back to the top of the loop, without reading
+                                * a new character. */
+                               goto loop_top;
+                       }
+                       /* My small mind cannot fathom backspaces and UTF-8 */
+                       putchar(c);
                }
                fclose(file);
-               fflush(stdout);
+               fflush_all();
        } while (*argv && *++argv);
  end:
+       setTermSettings(cin_fileno, &initial_settings);
        return 0;
 }