box/coreutils/echo.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * echo implementation for busybox
   4  *
   5  * Copyright (c) 1991, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   9  *
  10  * Original copyright notice is retained at the end of this file.
  11  */
  12
  13 /* BB_AUDIT SUSv3 compliant -- unless configured as fancy echo. */
  14 /* http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html */
  15
  16 /* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
  17  *
  18  * Because of behavioral differences, implemented configurable SUSv3
  19  * or 'fancy' gnu-ish behaviors.  Also, reduced size and fixed bugs.
  20  * 1) In handling '\c' escape, the previous version only suppressed the
  21  *     trailing newline.  SUSv3 specifies _no_ output after '\c'.
  22  * 2) SUSv3 specifies that octal escapes are of the form \0{#{#{#}}}.
  23  *    The previous version did not allow 4-digit octals.
  24  */
  25
  26 #include "libbb.h"
  27
  28 int bb_echo(char **argv)
  29 {
  30         const char *arg;
  31 #if !ENABLE_FEATURE_FANCY_ECHO
  32         enum {
  33                 eflag = '\\',
  34                 nflag = 1,  /* 1 -- print '\n' */
  35         };
  36         arg = *++argv;
  37         if (!arg)
  38                 goto newline_ret;
  39 #else
  40         const char *p;
  41         char nflag = 1;
  42         char eflag = 0;
  43
  44         while (1) {
  45                 arg = *++argv;
  46                 if (!arg)
  47                         goto newline_ret;
  48                 if (*arg != '-')
  49                         break;
  50
  51                 /* If it appears that we are handling options, then make sure
  52                  * that all of the options specified are actually valid.
  53                  * Otherwise, the string should just be echoed.
  54                  */
  55                 p = arg + 1;
  56                 if (!*p)        /* A single '-', so echo it. */
  57                         goto just_echo;
  58
  59                 do {
  60                         if (!strrchr("neE", *p))
  61                                 goto just_echo;
  62                 } while (*++p);
  63
  64                 /* All of the options in this arg are valid, so handle them. */
  65                 p = arg + 1;
  66                 do {
  67                         if (*p == 'n')
  68                                 nflag = 0;
  69                         if (*p == 'e')
  70                                 eflag = '\\';
  71                 } while (*++p);
  72         }
  73  just_echo:
  74 #endif
  75         while (1) {
  76                 /* arg is already == *argv and isn't NULL */
  77                 int c;
  78
  79                 if (!eflag) {
  80                         /* optimization for very common case */
  81                         fputs(arg, stdout);
  82                 } else while ((c = *arg++)) {
  83                         if (c == eflag) {       /* Check for escape seq. */
  84                                 if (*arg == 'c') {
  85                                         /* '\c' means cancel newline and
  86                                          * ignore all subsequent chars. */
  87                                         goto ret;
  88                                 }
  89 #if !ENABLE_FEATURE_FANCY_ECHO
  90                                 /* SUSv3 specifies that octal escapes must begin with '0'. */
  91                                 if ( (((unsigned char)*arg) - '1') >= 7)
  92 #endif
  93                                 {
  94                                         /* Since SUSv3 mandates a first digit of 0, 4-digit octals
  95                                         * of the form \0### are accepted. */
  96                                         if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
  97                                                 arg++;
  98                                         }
  99                                         /* bb_process_escape_sequence can handle nul correctly */
 100                                         c = bb_process_escape_sequence(&arg);
 101                                 }
 102                         }
 103                         putchar(c);
 104                 }
 105
 106                 arg = *++argv;
 107                 if (!arg)
 108                         break;
 109                 putchar(' ');
 110         }
 111
 112  newline_ret:
 113         if (nflag) {
 114                 putchar('\n');
 115         }
 116  ret:
 117         return fflush(stdout);
 118 }
 119
 120 /* This is a NOFORK applet. Be very careful! */
 121
 122 int echo_main(int argc, char** argv);
 123 int echo_main(int argc, char** argv)
 124 {
 125         return bb_echo(argv);
 126 }
 127
 128 /*-
 129  * Copyright (c) 1991, 1993
 130  *      The Regents of the University of California.  All rights reserved.
 131  *
 132  * This code is derived from software contributed to Berkeley by
 133  * Kenneth Almquist.
 134  *
 135  * Redistribution and use in source and binary forms, with or without
 136  * modification, are permitted provided that the following conditions
 137  * are met:
 138  * 1. Redistributions of source code must retain the above copyright
 139  *    notice, this list of conditions and the following disclaimer.
 140  * 2. Redistributions in binary form must reproduce the above copyright
 141  *    notice, this list of conditions and the following disclaimer in the
 142  *    documentation and/or other materials provided with the distribution.
 143  *
 144  * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
 145  *              ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
 146  *
 147  *      California, Berkeley and its contributors.
 148  * 4. Neither the name of the University nor the names of its contributors
 149  *    may be used to endorse or promote products derived from this software
 150  *    without specific prior written permission.
 151  *
 152  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 153  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 154  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 155  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 156  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 157  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 158  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 159  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 160  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 161  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 162  * SUCH DAMAGE.
 163  *
 164  *      @(#)echo.c      8.1 (Berkeley) 5/31/93
 165  */