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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