release/src/router/busybox/scripts/echo.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * echo implementation for busybox - used as a helper for testsuite/*
   4  * on systems lacking "echo -en"
   5  *
   6  * Copyright (c) 1991, 1993
   7  *      The Regents of the University of California.  All rights reserved.
   8  *
   9  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  10  *
  11  * Original copyright notice is retained at the end of this file.
  12  */
  13
  14 /* BB_AUDIT SUSv3 compliant -- unless configured as fancy echo. */
  15 /* http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html */
  16
  17 /* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
  18  *
  19  * Because of behavioral differences, implemented configurable SUSv3
  20  * or 'fancy' gnu-ish behaviors.  Also, reduced size and fixed bugs.
  21  * 1) In handling '\c' escape, the previous version only suppressed the
  22  *     trailing newline.  SUSv3 specifies _no_ output after '\c'.
  23  * 2) SUSv3 specifies that octal escapes are of the form \0{#{#{#}}}.
  24  *    The previous version did not allow 4-digit octals.
  25  */
  26
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <limits.h>
  30
  31 #define WANT_HEX_ESCAPES 1
  32
  33 /* Usual "this only works for ascii compatible encodings" disclaimer. */
  34 #undef _tolower
  35 #define _tolower(X) ((X)|((char) 0x20))
  36
  37 static char bb_process_escape_sequence(const char **ptr)
  38 {
  39         static const char charmap[] = {
  40                 'a',  'b',  'f',  'n',  'r',  't',  'v',  '\\', 0,
  41                 '\a', '\b', '\f', '\n', '\r', '\t', '\v', '\\', '\\' };
  42
  43         const char *p;
  44         const char *q;
  45         unsigned int num_digits;
  46         unsigned int r;
  47         unsigned int n;
  48         unsigned int d;
  49         unsigned int base;
  50
  51         num_digits = n = 0;
  52         base = 8;
  53         q = *ptr;
  54
  55 #ifdef WANT_HEX_ESCAPES
  56         if (*q == 'x') {
  57                 ++q;
  58                 base = 16;
  59                 ++num_digits;
  60         }
  61 #endif
  62
  63         do {
  64                 d = (unsigned char)(*q) - '0';
  65 #ifdef WANT_HEX_ESCAPES
  66                 if (d >= 10) {
  67                         d = (unsigned char)(_tolower(*q)) - 'a' + 10;
  68                 }
  69 #endif
  70
  71                 if (d >= base) {
  72 #ifdef WANT_HEX_ESCAPES
  73                         if ((base == 16) && (!--num_digits)) {
  74 /*                              return '\\'; */
  75                                 --q;
  76                         }
  77 #endif
  78                         break;
  79                 }
  80
  81                 r = n * base + d;
  82                 if (r > UCHAR_MAX) {
  83                         break;
  84                 }
  85
  86                 n = r;
  87                 ++q;
  88         } while (++num_digits < 3);
  89
  90         if (num_digits == 0) {  /* mnemonic escape sequence? */
  91                 p = charmap;
  92                 do {
  93                         if (*p == *q) {
  94                                 q++;
  95                                 break;
  96                         }
  97                 } while (*++p);
  98                 n = *(p + (sizeof(charmap)/2));
  99         }
 100
 101         *ptr = q;
 102
 103         return (char) n;
 104 }
 105
 106
 107 int main(int argc, char **argv)
 108 {
 109         const char *arg;
 110         const char *p;
 111         char nflag = 1;
 112         char eflag = 0;
 113
 114         /* We must check that stdout is not closed. */
 115         if (dup2(1, 1) != 1)
 116                 return -1;
 117
 118         while (1) {
 119                 arg = *++argv;
 120                 if (!arg)
 121                         goto newline_ret;
 122                 if (*arg != '-')
 123                         break;
 124
 125                 /* If it appears that we are handling options, then make sure
 126                  * that all of the options specified are actually valid.
 127                  * Otherwise, the string should just be echoed.
 128                  */
 129                 p = arg + 1;
 130                 if (!*p)        /* A single '-', so echo it. */
 131                         goto just_echo;
 132
 133                 do {
 134                         if (!strrchr("neE", *p))
 135                                 goto just_echo;
 136                 } while (*++p);
 137
 138                 /* All of the options in this arg are valid, so handle them. */
 139                 p = arg + 1;
 140                 do {
 141                         if (*p == 'n')
 142                                 nflag = 0;
 143                         if (*p == 'e')
 144                                 eflag = '\\';
 145                 } while (*++p);
 146         }
 147  just_echo:
 148         while (1) {
 149                 /* arg is already == *argv and isn't NULL */
 150                 int c;
 151
 152                 if (!eflag) {
 153                         /* optimization for very common case */
 154                         fputs(arg, stdout);
 155                 } else while ((c = *arg++)) {
 156                         if (c == eflag) {       /* Check for escape seq. */
 157                                 if (*arg == 'c') {
 158                                         /* '\c' means cancel newline and
 159                                          * ignore all subsequent chars. */
 160                                         goto ret;
 161                                 }
 162                                 {
 163                                         /* Since SUSv3 mandates a first digit of 0, 4-digit octals
 164                                         * of the form \0### are accepted. */
 165                                         if (*arg == '0') {
 166                                                 /* NB: don't turn "...\0" into "...\" */
 167                                                 if (arg[1] && ((unsigned char)(arg[1]) - '0') < 8) {
 168                                                         arg++;
 169                                                 }
 170                                         }
 171                                         /* bb_process_escape_sequence handles NUL correctly
 172                                          * ("...\" case. */
 173                                         c = bb_process_escape_sequence(&arg);
 174                                 }
 175                         }
 176                         putchar(c);
 177                 }
 178
 179                 arg = *++argv;
 180                 if (!arg)
 181                         break;
 182                 putchar(' ');
 183         }
 184
 185  newline_ret:
 186         if (nflag) {
 187                 putchar('\n');
 188         }
 189  ret:
 190         return fflush(NULL);
 191 }
 192
 193 /*-
 194  * Copyright (c) 1991, 1993
 195  *      The Regents of the University of California.  All rights reserved.
 196  *
 197  * This code is derived from software contributed to Berkeley by
 198  * Kenneth Almquist.
 199  *
 200  * Redistribution and use in source and binary forms, with or without
 201  * modification, are permitted provided that the following conditions
 202  * are met:
 203  * 1. Redistributions of source code must retain the above copyright
 204  *    notice, this list of conditions and the following disclaimer.
 205  * 2. Redistributions in binary form must reproduce the above copyright
 206  *    notice, this list of conditions and the following disclaimer in the
 207  *    documentation and/or other materials provided with the distribution.
 208  *
 209  * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
 210  *              ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
 211  *
 212  *      California, Berkeley and its contributors.
 213  * 4. Neither the name of the University nor the names of its contributors
 214  *    may be used to endorse or promote products derived from this software
 215  *    without specific prior written permission.
 216  *
 217  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 218  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 219  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 220  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 221  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 222  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 223  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 224  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 225  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 226  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 227  * SUCH DAMAGE.
 228  *
 229  *      @(#)echo.c      8.1 (Berkeley) 5/31/93
 230  */