dd: code shrink

[oweals/busybox.git] / util-linux / more.c

diff --git a/util-linux/more.c b/util-linux/more.c
index 93954660e1ee5f1fba293a0bed5fe50baae05e26..35957139711f20b89b3c5b793b66f5ccc9a1af0f 100644 (file)
--- a/util-linux/more.c
+++ b/util-linux/more.c
@@ -11,49 +11,54 @@
  *
  * Termios corrects by Vladimir Oleynik <dzo@simtreas.ru>
  *
- * Licensed under GPLv2 or later, see file License in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
-#include "libbb.h"
-#if ENABLE_FEATURE_USE_TERMIOS
-#include <termios.h>
-#endif /* FEATURE_USE_TERMIOS */
+//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"
 
-#if ENABLE_FEATURE_USE_TERMIOS
+/* 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) tcsetattr(fd, TCSANOW, argp)
+#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');
+       /* 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);
+       _exit(EXIT_FAILURE);
 }
 
-#else /* !FEATURE_USE_TERMIOS */
-#define INIT_G() ((void)0)
-#define setTermSettings(fd, argp) ((void)0)
-#endif /* FEATURE_USE_TERMIOS */
-
 #define CONVERTED_TAB_SIZE 8
 
 int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int more_main(int argc UNUSED_PARAM, char **argv)
 {
-       int c = c; /* for gcc */
+       int c = c; /* for compiler */
        int lines;
        int input = 0;
        int spaces = 0;
@@ -72,25 +77,24 @@ int more_main(int argc UNUSED_PARAM, char **argv)
         * 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);
-       bb_signals(0
-               + (1 << SIGINT)
-               + (1 << SIGQUIT)
-               + (1 << SIGTERM)
-               , gotsig);
-#endif
+       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);
+       }
 
        do {
                file = stdin;
@@ -116,12 +120,15 @@ int more_main(int argc UNUSED_PARAM, char **argv)
  loop_top:
                        if (input != 'r' && please_display_more_prompt) {
                                len = printf("--More-- ");
-                               if (st.st_size > 0) {
-                                       len += printf("(%d%% of %"OFF_FMT"d bytes)",
-                                               (int) (ftello(file)*100 / st.st_size),
+                               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(stdout);
+                               fflush_all();
 
                                /*
                                 * We've just displayed the "--More--" prompt, so now we need
@@ -130,9 +137,8 @@ int more_main(int argc UNUSED_PARAM, char **argv)
                                for (;;) {
                                        input = getc(cin);
                                        input = tolower(input);
-#if !ENABLE_FEATURE_USE_TERMIOS
-                                       printf("\033[A"); /* up cursor */
-#endif
+                                       if (!ENABLE_FEATURE_USE_TERMIOS)
+                                               printf("\033[A"); /* cursor up */
                                        /* Erase the last message */
                                        printf("\r%*s\r", len, "");
 
@@ -154,16 +160,16 @@ int more_main(int argc UNUSED_PARAM, char **argv)
 
                                /* 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;
-#endif
+                               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;
+                               spaces = ((unsigned)~len) % CONVERTED_TAB_SIZE;
                                c = ' ';
                        }
 
@@ -195,9 +201,10 @@ int more_main(int argc UNUSED_PARAM, char **argv)
                        }
                        /* 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(stdout);
+               fflush_all();
        } while (*argv && *++argv);
  end:
        setTermSettings(cin_fileno, &initial_settings);