vi: fix reading of file after last line
[oweals/busybox.git] / util-linux / more.c
index 72d58a6f4c1551204d15661cae7980c1e75b937e..35957139711f20b89b3c5b793b66f5ccc9a1af0f 100644 (file)
+/* vi: set sw=4 ts=4: */
 /*
  * Mini more implementation for busybox
  *
- * Copyright (C) 1998 by Erik Andersen <andersee@debian.org>
+ * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * Latest version blended together by Erik Andersen <andersen@codepoet.org>,
+ * based on the original more implementation by Bruce, and code from the
+ * Debian boot-floppies team.
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Termios corrects by Vladimir Oleynik <dzo@simtreas.ru>
  *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
+//usage:#define more_trivial_usage
+//usage:       "[FILE]..."
+//usage:#define more_full_usage "\n\n"
+//usage:       "View FILE (or stdin) one screenful at a time"
+//usage:
+//usage:#define more_example_usage
+//usage:       "$ dmesg | more\n"
+
+#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_stderr doesn't use stdio buffering,
+        * therefore it is safe in signal handler */
+       bb_putchar_stderr('\n');
+       setTermSettings(cin_fileno, &initial_settings);
+       _exit(EXIT_FAILURE);
+}
 
-/* Turning this off makes things a bit smaller (and less pretty) */
-#define BB_MORE_TERM
-
-
-
-#include "internal.h"
-#include <stdio.h>
-#include <fcntl.h>
-#include <signal.h>
-
-
-static const char more_usage[] = "[file ...]";
-
-
-/* ED: sparc termios is broken: revert back to old termio handling. */
-#ifdef BB_MORE_TERM
-
-
-#if defined (__sparc__)
-#      define USE_OLD_TERMIO
-#      include <termio.h>
-#      include <sys/ioctl.h>
-#      define termios termio
-#      define stty(fd,argp) ioctl(fd,TCSETAF,argp)
-#else
-#      include <termios.h>
-#      define stty(fd,argp) tcsetattr(fd,TCSANOW,argp)
-#endif
-
-    FILE *cin;
-    struct termios initial_settings, new_settings;
-
-    void gotsig(int sig) { 
-           stty(fileno(cin), &initial_settings);
-           exit( TRUE);
-    }
-#endif
+#define CONVERTED_TAB_SIZE 8
 
-extern 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=0, input=0;
-    int next_page=0;
-    struct stat st;    
-    FILE *file;
-
-    if ( strcmp(*argv,"--help")==0 || strcmp(*argv,"-h")==0 ) {
-       usage (more_usage);
-    }
-    argc--;
-    argv++;
-
-    while (argc >= 0) {
-       if (argc==0) {
-           file = stdin;
-       }
-       else
-           file = fopen(*argv, "r");
+       int c = c; /* for compiler */
+       int lines;
+       int input = 0;
+       int spaces = 0;
+       int please_display_more_prompt;
+       struct stat st;
+       FILE *file;
+       FILE *cin;
+       int len;
+       unsigned terminal_width;
+       unsigned terminal_height;
+
+       INIT_G();
 
-       if (file == NULL) {
-           perror(*argv);
-           exit(FALSE);
-       }
-       fstat(fileno(file), &st);
-
-#ifdef BB_MORE_TERM
-       cin = fopen("/dev/tty", "r");
+       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_for_read(CURRENT_TTY);
        if (!cin)
-           cin = fopen("/dev/console", "r");
-#ifdef USE_OLD_TERMIO
-       ioctl(fileno(cin),TCGETA,&initial_settings);
-#else
-       tcgetattr(fileno(cin),&initial_settings);
-#endif
-       new_settings = initial_settings;
-       new_settings.c_lflag &= ~ICANON;
-       new_settings.c_lflag &= ~ECHO;
-       stty(fileno(cin), &new_settings);
-       
-       (void) signal(SIGINT, gotsig);
-
-#endif
-       while ((c = getc(file)) != EOF) {
-           if ( next_page ) {
-               int len=0;
-               next_page = 0;
-               lines=0;
-               len = fprintf(stdout, "--More-- ");
-               if (file != stdin) {
-                   len += fprintf(stdout, "(%d%% of %ld bytes)", 
-                       (int) (100*( (double) ftell(file) / (double) st.st_size )),
-                       st.st_size);
-               }
-               len += fprintf(stdout, "%s",
-#ifdef BB_MORE_TERM
-                       ""
-#else
-                       "\n"
-#endif
-                       );
-
-               fflush(stdout);
-               input = getc( cin);
-
-#ifdef BB_MORE_TERM
-               /* Erase the "More" message */
-               while(len-- > 0)
-                   putc('\b', stdout);
-               while(len++ < 79)
-                   putc(' ', stdout);
-               while(len-- > 0)
-                   putc('\b', stdout);
-               fflush(stdout);
-#endif
-
-           }
-           if (input=='q')
-               goto end;
-           if (input==' ' &&  c == '\n' )
-               next_page = 1;
-           if ( c == '\n' && ++lines == 24 )
-               next_page = 1;
-           putc(c, stdout);
+               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 | 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);
        }
-       fclose(file);
-       fflush(stdout);
 
-       argc--;
-       argv++;
-    }
-end:
-#ifdef BB_MORE_TERM
-    gotsig(0);
-#endif 
-    exit(TRUE);
+       do {
+               file = stdin;
+               if (*argv) {
+                       file = fopen_or_warn(*argv, "r");
+                       if (!file)
+                               continue;
+               }
+               st.st_size = 0;
+               fstat(fileno(file), &st);
+
+               please_display_more_prompt = 0;
+               /* never returns w, h <= 1 */
+               get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
+               terminal_height -= 1;
+
+               len = 0;
+               lines = 0;
+               while (spaces || (c = getc(file)) != EOF) {
+                       int wrap;
+                       if (spaces)
+                               spaces--;
+ loop_top:
+                       if (input != 'r' && please_display_more_prompt) {
+                               len = printf("--More-- ");
+                               if (st.st_size != 0) {
+                                       uoff_t d = (uoff_t)st.st_size / 100;
+                                       if (d == 0)
+                                               d = 1;
+                                       len += printf("(%u%% of %"OFF_FMT"u bytes)",
+                                               (int) ((uoff_t)ftello(file) / d),
+                                               st.st_size);
+                               }
+                               fflush_all();
+
+                               /*
+                                * We've just displayed the "--More--" prompt, so now we need
+                                * to get input from the user.
+                                */
+                               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;
+                               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 = ((unsigned)~len) % CONVERTED_TAB_SIZE;
+                               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
+                        *
+                        * 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.
+                        */
+                       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 (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);
+                       die_if_ferror_stdout(); /* if tty was destroyed (closed xterm, etc) */
+               }
+               fclose(file);
+               fflush_all();
+       } while (*argv && *++argv);
+ end:
+       setTermSettings(cin_fileno, &initial_settings);
+       return 0;
 }
-