1 /* vi: set sw=4 ts=4: */
3 * echo implementation for busybox
5 * Copyright (c) 1991, 1993
6 * The Regents of the University of California. All rights reserved.
8 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
10 * Original copyright notice is retained at the end of this file.
13 /* BB_AUDIT SUSv3 compliant -- unless configured as fancy echo. */
14 /* http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html */
16 /* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
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.
28 /* argc is unused, but removing it precludes compiler from
29 * using call -> jump optimization */
30 int bb_echo(int argc, char **argv)
33 #if !ENABLE_FEATURE_FANCY_ECHO
36 nflag = 1, /* 1 -- print '\n' */
39 /* We must check that stdout is not closed.
40 * The reason for this is highly non-obvious.
41 * bb_echo is used from shell. Shell must correctly handle "echo foo"
42 * if stdout is closed. With stdio, output gets shoveled into
43 * stdout buffer, and even fflush cannot clear it out. It seems that
44 * even if libc receives EBADF on write attempts, it feels determined
45 * to output data no matter what. So it will try later,
46 * and possibly will clobber future output. Not good. */
58 /* We must check that stdout is not closed. */
69 /* If it appears that we are handling options, then make sure
70 * that all of the options specified are actually valid.
71 * Otherwise, the string should just be echoed.
74 if (!*p) /* A single '-', so echo it. */
78 if (!strrchr("neE", *p))
82 /* All of the options in this arg are valid, so handle them. */
94 /* arg is already == *argv and isn't NULL */
98 /* optimization for very common case */
100 } else while ((c = *arg++)) {
101 if (c == eflag) { /* Check for escape seq. */
103 /* '\c' means cancel newline and
104 * ignore all subsequent chars. */
107 #if !ENABLE_FEATURE_FANCY_ECHO
108 /* SUSv3 specifies that octal escapes must begin with '0'. */
109 if ( (((unsigned char)*arg) - '1') >= 7)
112 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
113 * of the form \0### are accepted. */
114 if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
117 /* bb_process_escape_sequence can handle nul correctly */
118 c = bb_process_escape_sequence(&arg);
135 return fflush(stdout);
138 /* This is a NOFORK applet. Be very careful! */
140 int echo_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
141 int echo_main(int argc, char **argv)
143 return bb_echo(argc, argv);
147 * Copyright (c) 1991, 1993
148 * The Regents of the University of California. All rights reserved.
150 * This code is derived from software contributed to Berkeley by
153 * Redistribution and use in source and binary forms, with or without
154 * modification, are permitted provided that the following conditions
156 * 1. Redistributions of source code must retain the above copyright
157 * notice, this list of conditions and the following disclaimer.
158 * 2. Redistributions in binary form must reproduce the above copyright
159 * notice, this list of conditions and the following disclaimer in the
160 * documentation and/or other materials provided with the distribution.
162 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
163 * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
165 * California, Berkeley and its contributors.
166 * 4. Neither the name of the University nor the names of its contributors
167 * may be used to endorse or promote products derived from this software
168 * without specific prior written permission.
170 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
171 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
172 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
173 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
174 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
175 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
176 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
177 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
178 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
179 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
182 * @(#)echo.c 8.1 (Berkeley) 5/31/93
185 #ifdef VERSION_WITH_WRITEV
186 /* We can't use stdio.
187 * The reason for this is highly non-obvious.
188 * bb_echo is used from shell. Shell must correctly handle "echo foo"
189 * if stdout is closed. With stdio, output gets shoveled into
190 * stdout buffer, and even fflush cannot clear it out. It seems that
191 * even if libc receives EBADF on write attempts, it feels determined
192 * to output data no matter what. So it will try later,
193 * and possibly will clobber future output. Not good.
195 * Using writev instead, with 'direct' conversion of argv vector.
198 int bb_echo(int argc, char **argv)
200 struct iovec io[argc];
201 struct iovec *cur_io = io;
204 #if !ENABLE_FEATURE_FANCY_ECHO
207 nflag = 1, /* 1 -- print '\n' */
223 /* If it appears that we are handling options, then make sure
224 * that all of the options specified are actually valid.
225 * Otherwise, the string should just be echoed.
228 if (!*p) /* A single '-', so echo it. */
232 if (!strrchr("neE", *p))
236 /* All of the options in this arg are valid, so handle them. */
249 /* arg is already == *argv and isn't NULL */
252 cur_io->iov_base = p = arg;
255 /* optimization for very common case */
257 } else while ((c = *arg++)) {
258 if (c == eflag) { /* Check for escape seq. */
260 /* '\c' means cancel newline and
261 * ignore all subsequent chars. */
262 cur_io->iov_len = p - (char*)cur_io->iov_base;
266 #if !ENABLE_FEATURE_FANCY_ECHO
267 /* SUSv3 specifies that octal escapes must begin with '0'. */
268 if ( (((unsigned char)*arg) - '1') >= 7)
271 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
272 * of the form \0### are accepted. */
273 if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
276 /* bb_process_escape_sequence can handle nul correctly */
277 c = bb_process_escape_sequence( (void*) &arg);
286 cur_io->iov_len = p - (char*)cur_io->iov_base;
294 cur_io->iov_base = (char*)"\n";
299 /* TODO: implement and use full_writev? */
300 return writev(1, io, (cur_io - io)) >= 0;