coreutils/catv.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * cat -v implementation for busybox
   4  *
   5  * Copyright (C) 2006 Rob Landley <rob@landley.net>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9
  10 /* See "Cat -v considered harmful" at
  11  * http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz */
  12
  13 //config:config CATV
  14 //config:       bool "catv"
  15 //config:       default y
  16 //config:       help
  17 //config:         Display nonprinting characters as escape sequences (like some
  18 //config:         implementations' cat -v option).
  19
  20 //applet:IF_CATV(APPLET(catv, BB_DIR_BIN, BB_SUID_DROP))
  21
  22 //kbuild:lib-$(CONFIG_CATV) += catv.o
  23
  24 //usage:#define catv_trivial_usage
  25 //usage:       "[-etv] [FILE]..."
  26 //usage:#define catv_full_usage "\n\n"
  27 //usage:       "Display nonprinting characters as ^x or M-x\n"
  28 //usage:     "\n        -e      End each line with $"
  29 //usage:     "\n        -t      Show tabs as ^I"
  30 //usage:     "\n        -v      Don't use ^x or M-x escapes"
  31
  32 #include "libbb.h"
  33 #include "common_bufsiz.h"
  34
  35 #define CATV_OPT_e (1<<0)
  36 #define CATV_OPT_t (1<<1)
  37 #define CATV_OPT_v (1<<2)
  38 struct BUG_const_mismatch {
  39         char BUG_const_mismatch[
  40                 CATV_OPT_e == VISIBLE_ENDLINE && CATV_OPT_t == VISIBLE_SHOW_TABS
  41                 ? 1 : -1
  42         ];
  43 };
  44
  45 int catv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  46 int catv_main(int argc UNUSED_PARAM, char **argv)
  47 {
  48         int retval = EXIT_SUCCESS;
  49         int fd;
  50         unsigned opts;
  51         opts = getopt32(argv, "etv");
  52         argv += optind;
  53 #if 0 /* These consts match, we can just pass "opts" to visible() */
  54         if (opts & CATV_OPT_e)
  55                 flags |= VISIBLE_ENDLINE;
  56         if (opts & CATV_OPT_t)
  57                 flags |= VISIBLE_SHOW_TABS;
  58 #endif
  59
  60         /* Read from stdin if there's nothing else to do. */
  61         if (!argv[0])
  62                 *--argv = (char*)"-";
  63
  64 #define read_buf bb_common_bufsiz1
  65         setup_common_bufsiz();
  66         do {
  67                 fd = open_or_warn_stdin(*argv);
  68                 if (fd < 0) {
  69                         retval = EXIT_FAILURE;
  70                         continue;
  71                 }
  72                 for (;;) {
  73                         int i, res;
  74
  75                         res = read(fd, read_buf, COMMON_BUFSIZE);
  76                         if (res < 0)
  77                                 retval = EXIT_FAILURE;
  78                         if (res <= 0)
  79                                 break;
  80                         for (i = 0; i < res; i++) {
  81                                 unsigned char c = read_buf[i];
  82                                 if (opts & CATV_OPT_v) {
  83                                         putchar(c);
  84                                 } else {
  85                                         char buf[sizeof("M-^c")];
  86                                         visible(c, buf, opts);
  87                                         fputs(buf, stdout);
  88                                 }
  89                         }
  90                 }
  91                 if (ENABLE_FEATURE_CLEAN_UP && fd)
  92                         close(fd);
  93         } while (*++argv);
  94
  95         fflush_stdout_and_exit(retval);
  96 }