[3320] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * echo implementation for busybox
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| 4 | *
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| 5 | * Copyright (c) 1991, 1993
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| 6 | * The Regents of the University of California. All rights reserved.
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| 7 | *
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| 8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 9 | *
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| 10 | * Original copyright notice is retained at the end of this file.
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| 11 | */
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| 12 |
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| 13 | /* BB_AUDIT SUSv3 compliant -- unless configured as fancy echo. */
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| 14 | /* http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html */
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| 15 |
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| 16 | /* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
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| 17 | *
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| 18 | * Because of behavioral differences, implemented configurable SUSv3
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| 19 | * or 'fancy' gnu-ish behaviors. Also, reduced size and fixed bugs.
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| 20 | * 1) In handling '\c' escape, the previous version only suppressed the
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| 21 | * trailing newline. SUSv3 specifies _no_ output after '\c'.
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| 22 | * 2) SUSv3 specifies that octal escapes are of the form \0{#{#{#}}}.
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| 23 | * The previous version did not allow 4-digit octals.
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| 24 | */
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| 25 |
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| 26 | #include "libbb.h"
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| 27 |
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| 28 | /* This is a NOFORK applet. Be very careful! */
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| 29 |
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| 30 | /* NB: can be used by shell even if not enabled as applet */
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| 31 |
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| 32 | int echo_main(int argc UNUSED_PARAM, char **argv)
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| 33 | {
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| 34 | const char *arg;
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| 35 | #if !ENABLE_FEATURE_FANCY_ECHO
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| 36 | enum {
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| 37 | eflag = '\\',
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| 38 | nflag = 1, /* 1 -- print '\n' */
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| 39 | };
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| 40 |
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| 41 | /* We must check that stdout is not closed.
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| 42 | * The reason for this is highly non-obvious.
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| 43 | * echo_main is used from shell. Shell must correctly handle "echo foo"
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| 44 | * if stdout is closed. With stdio, output gets shoveled into
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| 45 | * stdout buffer, and even fflush cannot clear it out. It seems that
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| 46 | * even if libc receives EBADF on write attempts, it feels determined
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| 47 | * to output data no matter what. So it will try later,
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| 48 | * and possibly will clobber future output. Not good. */
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| 49 | // TODO: check fcntl() & O_ACCMODE == O_WRONLY or O_RDWR?
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| 50 | if (fcntl(1, F_GETFL) == -1)
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| 51 | return 1; /* match coreutils 6.10 (sans error msg to stderr) */
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| 52 | //if (dup2(1, 1) != 1) - old way
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| 53 | // return 1;
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| 54 |
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| 55 | arg = *++argv;
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| 56 | if (!arg)
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| 57 | goto newline_ret;
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| 58 | #else
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| 59 | const char *p;
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| 60 | char nflag = 1;
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| 61 | char eflag = 0;
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| 62 |
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| 63 | /* We must check that stdout is not closed. */
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| 64 | if (fcntl(1, F_GETFL) == -1)
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| 65 | return 1;
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| 66 |
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| 67 | while (1) {
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| 68 | arg = *++argv;
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| 69 | if (!arg)
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| 70 | goto newline_ret;
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| 71 | if (*arg != '-')
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| 72 | break;
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| 73 |
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| 74 | /* If it appears that we are handling options, then make sure
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| 75 | * that all of the options specified are actually valid.
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| 76 | * Otherwise, the string should just be echoed.
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| 77 | */
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| 78 | p = arg + 1;
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| 79 | if (!*p) /* A single '-', so echo it. */
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| 80 | goto just_echo;
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| 81 |
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| 82 | do {
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| 83 | if (!strrchr("neE", *p))
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| 84 | goto just_echo;
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| 85 | } while (*++p);
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| 86 |
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| 87 | /* All of the options in this arg are valid, so handle them. */
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| 88 | p = arg + 1;
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| 89 | do {
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| 90 | if (*p == 'n')
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| 91 | nflag = 0;
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| 92 | if (*p == 'e')
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| 93 | eflag = '\\';
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| 94 | } while (*++p);
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| 95 | }
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| 96 | just_echo:
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| 97 | #endif
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| 98 | while (1) {
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| 99 | /* arg is already == *argv and isn't NULL */
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| 100 | int c;
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| 101 |
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| 102 | if (!eflag) {
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| 103 | /* optimization for very common case */
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| 104 | fputs(arg, stdout);
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| 105 | } else while ((c = *arg++)) {
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| 106 | if (c == eflag) { /* Check for escape seq. */
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| 107 | if (*arg == 'c') {
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| 108 | /* '\c' means cancel newline and
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| 109 | * ignore all subsequent chars. */
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| 110 | goto ret;
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| 111 | }
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| 112 | #if !ENABLE_FEATURE_FANCY_ECHO
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| 113 | /* SUSv3 specifies that octal escapes must begin with '0'. */
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| 114 | if ( ((int)(unsigned char)(*arg) - '0') >= 8) /* '8' or bigger */
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| 115 | #endif
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| 116 | {
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| 117 | /* Since SUSv3 mandates a first digit of 0, 4-digit octals
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| 118 | * of the form \0### are accepted. */
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| 119 | if (*arg == '0') {
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| 120 | /* NB: don't turn "...\0" into "...\" */
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| 121 | if (arg[1] && ((unsigned char)(arg[1]) - '0') < 8) {
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| 122 | arg++;
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| 123 | }
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| 124 | }
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| 125 | /* bb_process_escape_sequence handles NUL correctly
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| 126 | * ("...\" case). */
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| 127 | c = bb_process_escape_sequence(&arg);
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| 128 | }
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| 129 | }
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| 130 | bb_putchar(c);
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| 131 | }
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| 132 |
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| 133 | arg = *++argv;
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| 134 | if (!arg)
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| 135 | break;
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| 136 | bb_putchar(' ');
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| 137 | }
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| 138 |
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| 139 | newline_ret:
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| 140 | if (nflag) {
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| 141 | bb_putchar('\n');
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| 142 | }
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| 143 | ret:
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| 144 | return fflush_all();
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| 145 | }
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| 146 |
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| 147 | /*-
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| 148 | * Copyright (c) 1991, 1993
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| 149 | * The Regents of the University of California. All rights reserved.
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| 150 | *
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| 151 | * This code is derived from software contributed to Berkeley by
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| 152 | * Kenneth Almquist.
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| 153 | *
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| 154 | * Redistribution and use in source and binary forms, with or without
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| 155 | * modification, are permitted provided that the following conditions
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| 156 | * are met:
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| 157 | * 1. Redistributions of source code must retain the above copyright
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| 158 | * notice, this list of conditions and the following disclaimer.
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| 159 | * 2. Redistributions in binary form must reproduce the above copyright
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| 160 | * notice, this list of conditions and the following disclaimer in the
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| 161 | * documentation and/or other materials provided with the distribution.
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| 162 | *
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| 163 | * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
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| 164 | * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
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| 165 | *
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| 166 | * California, Berkeley and its contributors.
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| 167 | * 4. Neither the name of the University nor the names of its contributors
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| 168 | * may be used to endorse or promote products derived from this software
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| 169 | * without specific prior written permission.
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| 170 | *
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| 171 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 172 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 173 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 174 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 175 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 176 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 177 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 178 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 179 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 180 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 181 | * SUCH DAMAGE.
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| 182 | *
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| 183 | * @(#)echo.c 8.1 (Berkeley) 5/31/93
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| 184 | */
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| 185 |
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| 186 | #ifdef VERSION_WITH_WRITEV
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| 187 | /* We can't use stdio.
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| 188 | * The reason for this is highly non-obvious.
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| 189 | * echo_main is used from shell. Shell must correctly handle "echo foo"
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| 190 | * if stdout is closed. With stdio, output gets shoveled into
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| 191 | * stdout buffer, and even fflush cannot clear it out. It seems that
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| 192 | * even if libc receives EBADF on write attempts, it feels determined
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| 193 | * to output data no matter what. So it will try later,
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| 194 | * and possibly will clobber future output. Not good.
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| 195 | *
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| 196 | * Using writev instead, with 'direct' conversion of argv vector.
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| 197 | */
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| 198 |
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| 199 | int echo_main(int argc, char **argv)
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| 200 | {
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| 201 | struct iovec io[argc];
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| 202 | struct iovec *cur_io = io;
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| 203 | char *arg;
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| 204 | char *p;
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| 205 | #if !ENABLE_FEATURE_FANCY_ECHO
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| 206 | enum {
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| 207 | eflag = '\\',
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| 208 | nflag = 1, /* 1 -- print '\n' */
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| 209 | };
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| 210 | arg = *++argv;
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| 211 | if (!arg)
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| 212 | goto newline_ret;
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| 213 | #else
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| 214 | char nflag = 1;
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| 215 | char eflag = 0;
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| 216 |
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| 217 | while (1) {
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| 218 | arg = *++argv;
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| 219 | if (!arg)
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| 220 | goto newline_ret;
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| 221 | if (*arg != '-')
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| 222 | break;
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| 223 |
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| 224 | /* If it appears that we are handling options, then make sure
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| 225 | * that all of the options specified are actually valid.
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| 226 | * Otherwise, the string should just be echoed.
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| 227 | */
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| 228 | p = arg + 1;
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| 229 | if (!*p) /* A single '-', so echo it. */
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| 230 | goto just_echo;
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| 231 |
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| 232 | do {
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| 233 | if (!strrchr("neE", *p))
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| 234 | goto just_echo;
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| 235 | } while (*++p);
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| 236 |
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| 237 | /* All of the options in this arg are valid, so handle them. */
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| 238 | p = arg + 1;
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| 239 | do {
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| 240 | if (*p == 'n')
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| 241 | nflag = 0;
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| 242 | if (*p == 'e')
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| 243 | eflag = '\\';
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| 244 | } while (*++p);
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| 245 | }
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| 246 | just_echo:
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| 247 | #endif
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| 248 |
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| 249 | while (1) {
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| 250 | /* arg is already == *argv and isn't NULL */
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| 251 | int c;
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| 252 |
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| 253 | cur_io->iov_base = p = arg;
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| 254 |
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| 255 | if (!eflag) {
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| 256 | /* optimization for very common case */
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| 257 | p += strlen(arg);
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| 258 | } else while ((c = *arg++)) {
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| 259 | if (c == eflag) { /* Check for escape seq. */
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| 260 | if (*arg == 'c') {
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| 261 | /* '\c' means cancel newline and
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| 262 | * ignore all subsequent chars. */
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| 263 | cur_io->iov_len = p - (char*)cur_io->iov_base;
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| 264 | cur_io++;
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| 265 | goto ret;
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| 266 | }
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| 267 | #if !ENABLE_FEATURE_FANCY_ECHO
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| 268 | /* SUSv3 specifies that octal escapes must begin with '0'. */
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| 269 | if ( (((unsigned char)*arg) - '1') >= 7)
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| 270 | #endif
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| 271 | {
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| 272 | /* Since SUSv3 mandates a first digit of 0, 4-digit octals
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| 273 | * of the form \0### are accepted. */
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| 274 | if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
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| 275 | arg++;
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| 276 | }
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| 277 | /* bb_process_escape_sequence can handle nul correctly */
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| 278 | c = bb_process_escape_sequence( (void*) &arg);
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| 279 | }
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| 280 | }
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| 281 | *p++ = c;
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| 282 | }
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| 283 |
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| 284 | arg = *++argv;
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| 285 | if (arg)
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| 286 | *p++ = ' ';
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| 287 | cur_io->iov_len = p - (char*)cur_io->iov_base;
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| 288 | cur_io++;
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| 289 | if (!arg)
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| 290 | break;
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| 291 | }
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| 292 |
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| 293 | newline_ret:
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| 294 | if (nflag) {
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| 295 | cur_io->iov_base = (char*)"\n";
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| 296 | cur_io->iov_len = 1;
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| 297 | cur_io++;
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| 298 | }
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| 299 | ret:
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| 300 | /* TODO: implement and use full_writev? */
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| 301 | return writev(1, io, (cur_io - io)) >= 0;
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| 302 | }
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| 303 | #endif
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