[821] | 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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[2725] | 8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[821] | 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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[1765] | 23 | * The previous version did not allow 4-digit octals.
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[821] | 24 | */
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| 25 |
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[3232] | 26 | //usage:#define echo_trivial_usage
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| 27 | //usage: IF_FEATURE_FANCY_ECHO("[-neE] ") "[ARG]..."
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| 28 | //usage:#define echo_full_usage "\n\n"
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| 29 | //usage: "Print the specified ARGs to stdout"
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| 30 | //usage: IF_FEATURE_FANCY_ECHO( "\n"
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| 31 | //usage: "\n -n Suppress trailing newline"
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| 32 | //usage: "\n -e Interpret backslash escapes (i.e., \\t=tab)"
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| 33 | //usage: "\n -E Don't interpret backslash escapes (default)"
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| 34 | //usage: )
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| 35 | //usage:
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| 36 | //usage:#define echo_example_usage
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| 37 | //usage: "$ echo \"Erik is cool\"\n"
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| 38 | //usage: "Erik is cool\n"
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| 39 | //usage: IF_FEATURE_FANCY_ECHO("$ echo -e \"Erik\\nis\\ncool\"\n"
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| 40 | //usage: "Erik\n"
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| 41 | //usage: "is\n"
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| 42 | //usage: "cool\n"
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| 43 | //usage: "$ echo \"Erik\\nis\\ncool\"\n"
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| 44 | //usage: "Erik\\nis\\ncool\n")
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| 45 |
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[1765] | 46 | #include "libbb.h"
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[821] | 47 |
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[2725] | 48 | /* This is a NOFORK applet. Be very careful! */
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| 49 |
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| 50 | /* NB: can be used by shell even if not enabled as applet */
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| 51 |
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[3232] | 52 | /*
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| 53 | * NB2: we don't use stdio, we need better error handing.
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| 54 | * Examples include writing into non-opened stdout and error on write.
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| 55 | *
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| 56 | * With stdio, output gets shoveled into stdout buffer, and even
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| 57 | * fflush cannot clear it out. It seems that even if libc receives
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| 58 | * EBADF on write attempts, it feels determined to output data no matter what.
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| 59 | * If echo is called by shell, it will try writing again later, and possibly
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| 60 | * will clobber future output. Not good.
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| 61 | *
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| 62 | * Solaris has fpurge which discards buffered input. glibc has __fpurge.
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| 63 | * But this function is not standard.
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| 64 | */
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| 65 |
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[2725] | 66 | int echo_main(int argc UNUSED_PARAM, char **argv)
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[821] | 67 | {
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[3232] | 68 | char **pp;
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[1765] | 69 | const char *arg;
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[3232] | 70 | char *out;
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| 71 | char *buffer;
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| 72 | unsigned buflen;
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[1765] | 73 | #if !ENABLE_FEATURE_FANCY_ECHO
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| 74 | enum {
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| 75 | eflag = '\\',
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| 76 | nflag = 1, /* 1 -- print '\n' */
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| 77 | };
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[2725] | 78 |
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[3232] | 79 | argv++;
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[821] | 80 | #else
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[1765] | 81 | char nflag = 1;
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| 82 | char eflag = 0;
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[821] | 83 |
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[3232] | 84 | while ((arg = *++argv) != NULL) {
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| 85 | char n, e;
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[2725] | 86 |
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[3232] | 87 | if (arg[0] != '-')
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| 88 | break; /* not an option arg, echo it */
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[1765] | 89 |
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[821] | 90 | /* If it appears that we are handling options, then make sure
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| 91 | * that all of the options specified are actually valid.
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| 92 | * Otherwise, the string should just be echoed.
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| 93 | */
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[3232] | 94 | arg++;
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| 95 | n = nflag;
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| 96 | e = eflag;
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[821] | 97 | do {
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[3232] | 98 | if (*arg == 'n')
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| 99 | n = 0;
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| 100 | else if (*arg == 'e')
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| 101 | e = '\\';
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| 102 | else if (*arg != 'E') {
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| 103 | /* "-ccc" arg with one of c's invalid, echo it */
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| 104 | /* arg consisting from just "-" also handled here */
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[821] | 105 | goto just_echo;
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[3232] | 106 | }
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| 107 | } while (*++arg);
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| 108 | nflag = n;
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| 109 | eflag = e;
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[821] | 110 | }
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[1765] | 111 | just_echo:
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[821] | 112 | #endif
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[3232] | 113 |
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| 114 | buflen = 0;
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| 115 | pp = argv;
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| 116 | while ((arg = *pp) != NULL) {
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| 117 | buflen += strlen(arg) + 1;
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| 118 | pp++;
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| 119 | }
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| 120 | out = buffer = xmalloc(buflen + 1); /* +1 is needed for "no args" case */
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| 121 |
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| 122 | while ((arg = *argv) != NULL) {
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[1765] | 123 | int c;
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[821] | 124 |
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[1765] | 125 | if (!eflag) {
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| 126 | /* optimization for very common case */
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[3232] | 127 | out = stpcpy(out, arg);
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| 128 | } else
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| 129 | while ((c = *arg++) != '\0') {
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| 130 | if (c == eflag) {
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| 131 | /* This is an "\x" sequence */
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| 132 |
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[1765] | 133 | if (*arg == 'c') {
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[3232] | 134 | /* "\c" means cancel newline and
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[821] | 135 | * ignore all subsequent chars. */
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[3232] | 136 | goto do_write;
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[821] | 137 | }
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[3232] | 138 | /* Since SUSv3 mandates a first digit of 0, 4-digit octals
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| 139 | * of the form \0### are accepted. */
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| 140 | if (*arg == '0') {
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| 141 | if ((unsigned char)(arg[1] - '0') < 8) {
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| 142 | /* 2nd char is 0..7: skip leading '0' */
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| 143 | arg++;
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[821] | 144 | }
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| 145 | }
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[3232] | 146 | /* bb_process_escape_sequence handles NUL correctly
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| 147 | * ("...\" case). */
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| 148 | {
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| 149 | /* optimization: don't force arg to be on-stack,
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| 150 | * use another variable for that. ~30 bytes win */
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| 151 | const char *z = arg;
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| 152 | c = bb_process_escape_sequence(&z);
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| 153 | arg = z;
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| 154 | }
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[821] | 155 | }
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[3232] | 156 | *out++ = c;
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[821] | 157 | }
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| 158 |
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[3232] | 159 | if (!*++argv)
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[1765] | 160 | break;
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[3232] | 161 | *out++ = ' ';
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[821] | 162 | }
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| 163 |
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| 164 | if (nflag) {
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[3232] | 165 | *out++ = '\n';
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[821] | 166 | }
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[3232] | 167 |
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| 168 | do_write:
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| 169 | /* Careful to error out on partial writes too (think ENOSPC!) */
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| 170 | errno = 0;
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| 171 | /*r =*/ full_write(STDOUT_FILENO, buffer, out - buffer);
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| 172 | free(buffer);
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| 173 | if (/*WRONG:r < 0*/ errno) {
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| 174 | bb_perror_msg(bb_msg_write_error);
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| 175 | return 1;
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| 176 | }
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| 177 | return 0;
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[821] | 178 | }
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| 179 |
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[3232] | 180 | /*
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[821] | 181 | * Copyright (c) 1991, 1993
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| 182 | * The Regents of the University of California. All rights reserved.
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| 183 | *
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| 184 | * This code is derived from software contributed to Berkeley by
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| 185 | * Kenneth Almquist.
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| 186 | *
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| 187 | * Redistribution and use in source and binary forms, with or without
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| 188 | * modification, are permitted provided that the following conditions
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| 189 | * are met:
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| 190 | * 1. Redistributions of source code must retain the above copyright
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| 191 | * notice, this list of conditions and the following disclaimer.
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| 192 | * 2. Redistributions in binary form must reproduce the above copyright
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| 193 | * notice, this list of conditions and the following disclaimer in the
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| 194 | * documentation and/or other materials provided with the distribution.
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| 195 | *
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| 196 | * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
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| 197 | * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
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| 198 | *
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| 199 | * California, Berkeley and its contributors.
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| 200 | * 4. Neither the name of the University nor the names of its contributors
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| 201 | * may be used to endorse or promote products derived from this software
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| 202 | * without specific prior written permission.
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| 203 | *
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| 204 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 205 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 206 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 207 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 208 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 209 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 210 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 211 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 212 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 213 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 214 | * SUCH DAMAGE.
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| 215 | *
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| 216 | * @(#)echo.c 8.1 (Berkeley) 5/31/93
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| 217 | */
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[2725] | 218 |
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| 219 | #ifdef VERSION_WITH_WRITEV
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| 220 | /* We can't use stdio.
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| 221 | * The reason for this is highly non-obvious.
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| 222 | * echo_main is used from shell. Shell must correctly handle "echo foo"
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| 223 | * if stdout is closed. With stdio, output gets shoveled into
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| 224 | * stdout buffer, and even fflush cannot clear it out. It seems that
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| 225 | * even if libc receives EBADF on write attempts, it feels determined
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| 226 | * to output data no matter what. So it will try later,
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| 227 | * and possibly will clobber future output. Not good.
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| 228 | *
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| 229 | * Using writev instead, with 'direct' conversion of argv vector.
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| 230 | */
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| 231 |
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| 232 | int echo_main(int argc, char **argv)
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| 233 | {
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| 234 | struct iovec io[argc];
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| 235 | struct iovec *cur_io = io;
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| 236 | char *arg;
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| 237 | char *p;
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| 238 | #if !ENABLE_FEATURE_FANCY_ECHO
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| 239 | enum {
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| 240 | eflag = '\\',
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| 241 | nflag = 1, /* 1 -- print '\n' */
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| 242 | };
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| 243 | arg = *++argv;
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| 244 | if (!arg)
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| 245 | goto newline_ret;
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| 246 | #else
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| 247 | char nflag = 1;
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| 248 | char eflag = 0;
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| 249 |
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| 250 | while (1) {
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| 251 | arg = *++argv;
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| 252 | if (!arg)
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| 253 | goto newline_ret;
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| 254 | if (*arg != '-')
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| 255 | break;
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| 256 |
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| 257 | /* If it appears that we are handling options, then make sure
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| 258 | * that all of the options specified are actually valid.
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| 259 | * Otherwise, the string should just be echoed.
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| 260 | */
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| 261 | p = arg + 1;
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| 262 | if (!*p) /* A single '-', so echo it. */
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| 263 | goto just_echo;
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| 264 |
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| 265 | do {
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[3232] | 266 | if (!strchr("neE", *p))
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[2725] | 267 | goto just_echo;
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| 268 | } while (*++p);
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| 269 |
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| 270 | /* All of the options in this arg are valid, so handle them. */
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| 271 | p = arg + 1;
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| 272 | do {
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| 273 | if (*p == 'n')
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| 274 | nflag = 0;
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| 275 | if (*p == 'e')
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| 276 | eflag = '\\';
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| 277 | } while (*++p);
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| 278 | }
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| 279 | just_echo:
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| 280 | #endif
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| 281 |
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| 282 | while (1) {
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| 283 | /* arg is already == *argv and isn't NULL */
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| 284 | int c;
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| 285 |
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| 286 | cur_io->iov_base = p = arg;
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| 287 |
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| 288 | if (!eflag) {
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| 289 | /* optimization for very common case */
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| 290 | p += strlen(arg);
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| 291 | } else while ((c = *arg++)) {
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[3232] | 292 | if (c == eflag) {
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| 293 | /* This is an "\x" sequence */
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| 294 |
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[2725] | 295 | if (*arg == 'c') {
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[3232] | 296 | /* "\c" means cancel newline and
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[2725] | 297 | * ignore all subsequent chars. */
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| 298 | cur_io->iov_len = p - (char*)cur_io->iov_base;
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| 299 | cur_io++;
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| 300 | goto ret;
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| 301 | }
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[3232] | 302 | /* Since SUSv3 mandates a first digit of 0, 4-digit octals
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| 303 | * of the form \0### are accepted. */
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| 304 | if (*arg == '0' && (unsigned char)(arg[1] - '0') < 8) {
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| 305 | arg++;
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[2725] | 306 | }
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[3232] | 307 | /* bb_process_escape_sequence can handle nul correctly */
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| 308 | c = bb_process_escape_sequence( (void*) &arg);
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[2725] | 309 | }
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| 310 | *p++ = c;
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| 311 | }
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| 312 |
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| 313 | arg = *++argv;
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| 314 | if (arg)
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| 315 | *p++ = ' ';
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| 316 | cur_io->iov_len = p - (char*)cur_io->iov_base;
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| 317 | cur_io++;
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| 318 | if (!arg)
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| 319 | break;
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| 320 | }
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| 321 |
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| 322 | newline_ret:
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| 323 | if (nflag) {
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| 324 | cur_io->iov_base = (char*)"\n";
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| 325 | cur_io->iov_len = 1;
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| 326 | cur_io++;
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| 327 | }
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| 328 | ret:
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| 329 | /* TODO: implement and use full_writev? */
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| 330 | return writev(1, io, (cur_io - io)) >= 0;
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| 331 | }
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| 332 | #endif
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