coreutils/cat.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * cat implementation for busybox
   4  *
   5  * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
   6  *
   7  * Licensed under GPLv2, see file LICENSE in this source tree.
   8  */
   9 //config:config CAT
  10 //config:       bool "cat (5.8 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       cat is used to concatenate files and print them to the standard
  14 //config:       output. Enable this option if you wish to enable the 'cat' utility.
  15 //config:
  16 //config:config FEATURE_CATN
  17 //config:       bool "Enable -n and -b options"
  18 //config:       default y
  19 //config:       depends on CAT
  20 //config:       help
  21 //config:       -n numbers all output lines while -b numbers nonempty output lines.
  22 //config:
  23 //config:config FEATURE_CATV
  24 //config:       bool "cat -v[etA]"
  25 //config:       default y
  26 //config:       depends on CAT
  27 //config:       help
  28 //config:       Display nonprinting characters as escape sequences
  29
  30 //applet:IF_CAT(APPLET(cat, BB_DIR_BIN, BB_SUID_DROP))
  31
  32 //kbuild:lib-$(CONFIG_CAT) += cat.o
  33
  34 /* BB_AUDIT SUSv3 compliant */
  35 /* http://www.opengroup.org/onlinepubs/007904975/utilities/cat.html */
  36
  37 //usage:#if ENABLE_FEATURE_CATN || ENABLE_FEATURE_CATV
  38 //usage:#define cat_trivial_usage
  39 //usage:       "[-" IF_FEATURE_CATN("nb") IF_FEATURE_CATV("vteA") "] [FILE]..."
  40 //usage:#else
  41 //usage:#define cat_trivial_usage
  42 //usage:       "[FILE]..."
  43 //usage:#endif
  44 //usage:#define cat_full_usage "\n\n"
  45 //usage:       "Print FILEs to stdout\n"
  46 //usage:        IF_FEATURE_CATN(
  47 //usage:     "\n        -n      Number output lines"
  48 //usage:     "\n        -b      Number nonempty lines"
  49 //usage:        )
  50 //usage:        IF_FEATURE_CATV(
  51 //usage:     "\n        -v      Show nonprinting characters as ^x or M-x"
  52 //usage:     "\n        -t      ...and tabs as ^I"
  53 //usage:     "\n        -e      ...and end lines with $"
  54 //usage:     "\n        -A      Same as -vte"
  55 //usage:        )
  56 /*
  57   Longopts not implemented yet:
  58       --number-nonblank    number nonempty output lines, overrides -n
  59       --number             number all output lines
  60       --show-nonprinting   use ^ and M- notation, except for LFD and TAB
  61       --show-all           equivalent to -vet
  62   Not implemented yet:
  63   -E, --show-ends          display $ at end of each line (-e sans -v)
  64   -T, --show-tabs          display TAB characters as ^I (-t sans -v)
  65   -s, --squeeze-blank      suppress repeated empty output lines
  66 */
  67 //usage:
  68 //usage:#define cat_example_usage
  69 //usage:       "$ cat /proc/uptime\n"
  70 //usage:       "110716.72 17.67"
  71
  72 #include "libbb.h"
  73 #include "common_bufsiz.h"
  74
  75 #if ENABLE_FEATURE_CATV
  76 /*
  77  * cat -v implementation for busybox
  78  *
  79  * Copyright (C) 2006 Rob Landley <rob@landley.net>
  80  *
  81  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  82  */
  83 /* Rob had "cat -v" implemented as a separate applet, catv.
  84  * See "cat -v considered harmful" at
  85  * http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz
  86  * From USENIX Summer Conference Proceedings, 1983
  87  * """
  88  * The talk reviews reasons for UNIX's popularity and shows, using UCB cat
  89  * as a primary example, how UNIX has grown fat. cat isn't for printing
  90  * files with line numbers, it isn't for compressing multiple blank lines,
  91  * it's not for looking at non-printing ASCII characters, it's for
  92  * concatenating files.
  93  * We are reminded that ls isn't the place for code to break a single column
  94  * into multiple ones, and that mailnews shouldn't have its own more
  95  * processing or joke encryption code.
  96  * """
  97  *
  98  * I agree with the argument. Unfortunately, this ship has sailed (1983...).
  99  * There are dozens of Linux distros and each of them has "cat" which supports -v.
 100  * It's unrealistic for us to "reeducate" them to use our, incompatible way
 101  * to achieve "cat -v" effect. The actual effect would be "users pissed off
 102  * by gratuitous incompatibility".
 103  */
 104 #define CAT_OPT_e (1<<0)
 105 #define CAT_OPT_t (1<<1)
 106 #define CAT_OPT_v (1<<2)
 107 /* -A occupies bit (1<<3) */
 108 #define CAT_OPT_n ((1<<4) * ENABLE_FEATURE_CATN)
 109 #define CAT_OPT_b ((1<<5) * ENABLE_FEATURE_CATN)
 110 static int catv(unsigned opts, char **argv)
 111 {
 112         int retval = EXIT_SUCCESS;
 113         int fd;
 114 #if ENABLE_FEATURE_CATN
 115         bool eol_seen = (opts & (CAT_OPT_n|CAT_OPT_b));
 116         unsigned eol_char = (eol_seen ? '\n' : 0x100);
 117         unsigned skip_num_on = (opts & CAT_OPT_b) ? '\n' : 0x100;
 118         unsigned lineno = 0;
 119 #endif
 120
 121         BUILD_BUG_ON(CAT_OPT_e != VISIBLE_ENDLINE);
 122         BUILD_BUG_ON(CAT_OPT_t != VISIBLE_SHOW_TABS);
 123 #if 0 /* These consts match, we can just pass "opts" to visible() */
 124         if (opts & CAT_OPT_e)
 125                 flags |= VISIBLE_ENDLINE;
 126         if (opts & CAT_OPT_t)
 127                 flags |= VISIBLE_SHOW_TABS;
 128 #endif
 129
 130 #define read_buf bb_common_bufsiz1
 131         setup_common_bufsiz();
 132         do {
 133                 fd = open_or_warn_stdin(*argv);
 134                 if (fd < 0) {
 135                         retval = EXIT_FAILURE;
 136                         continue;
 137                 }
 138                 for (;;) {
 139                         int i, res;
 140
 141                         res = read(fd, read_buf, COMMON_BUFSIZE);
 142                         if (res < 0)
 143                                 retval = EXIT_FAILURE;
 144                         if (res <= 0)
 145                                 break;
 146                         for (i = 0; i < res; i++) {
 147                                 unsigned char c = read_buf[i];
 148                                 char buf[sizeof("M-^c")];
 149 #if ENABLE_FEATURE_CATN
 150                                 if (eol_seen && c != skip_num_on)
 151                                         printf("%6u  ", ++lineno);
 152                                 eol_seen = (c == eol_char);
 153 #endif
 154                                 visible(c, buf, opts);
 155                                 fputs_stdout(buf);
 156                         }
 157                 }
 158                 if (ENABLE_FEATURE_CLEAN_UP && fd)
 159                         close(fd);
 160         } while (*++argv);
 161
 162         fflush_stdout_and_exit(retval);
 163 }
 164 #undef CAT_OPT_n
 165 #undef CAT_OPT_b
 166 #endif
 167
 168 int cat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 169 int cat_main(int argc UNUSED_PARAM, char **argv)
 170 {
 171 #if ENABLE_FEATURE_CATV || ENABLE_FEATURE_CATN
 172         unsigned opts;
 173
 174         opts =
 175 #endif
 176         getopt32(argv, IF_FEATURE_CATV("^")
 177                 /* -u is ignored ("unbuffered") */
 178                 IF_FEATURE_CATV("etvA")IF_FEATURE_CATN("nb")"u"
 179                 IF_FEATURE_CATV("\0" "Aetv" /* -A == -vet */)
 180         );
 181         argv += optind;
 182
 183         /* Read from stdin if there's nothing else to do. */
 184         if (!argv[0])
 185                 *--argv = (char*)"-";
 186
 187 #if ENABLE_FEATURE_CATV
 188         if (opts & 7)
 189                 return catv(opts, argv);
 190         opts >>= 4;
 191 #endif
 192
 193 #if ENABLE_FEATURE_CATN
 194 # define CAT_OPT_n (1<<0)
 195 # define CAT_OPT_b (1<<1)
 196         if (opts & (CAT_OPT_n|CAT_OPT_b)) { /* -n or -b */
 197                 struct number_state ns;
 198                 int exitcode;
 199
 200                 ns.width = 6;
 201                 ns.start = 1;
 202                 ns.inc = 1;
 203                 ns.sep = "\t";
 204                 ns.empty_str = NULL;
 205                 ns.all = !(opts & CAT_OPT_b); /* -n without -b */
 206                 ns.nonempty = (opts & CAT_OPT_b); /* -b (with or without -n) */
 207                 exitcode = EXIT_SUCCESS;
 208                 do {
 209                         exitcode |= print_numbered_lines(&ns, *argv);
 210                 } while (*++argv);
 211                 fflush_stdout_and_exit(exitcode);
 212         }
 213         /*opts >>= 2;*/
 214 #endif
 215
 216         return bb_cat(argv);
 217 }