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 /* This is a NOFORK applet. Be very careful! */
30 /* argc is unused, but removing it precludes compiler from
31 * using call -> jump optimization */
33 int echo_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
34 int echo_main(int argc, char **argv)
37 #if !ENABLE_FEATURE_FANCY_ECHO
40 nflag = 1, /* 1 -- print '\n' */
43 /* We must check that stdout is not closed.
44 * The reason for this is highly non-obvious.
45 * echo_main is used from shell. Shell must correctly handle "echo foo"
46 * if stdout is closed. With stdio, output gets shoveled into
47 * stdout buffer, and even fflush cannot clear it out. It seems that
48 * even if libc receives EBADF on write attempts, it feels determined
49 * to output data no matter what. So it will try later,
50 * and possibly will clobber future output. Not good. */
62 /* We must check that stdout is not closed. */
73 /* If it appears that we are handling options, then make sure
74 * that all of the options specified are actually valid.
75 * Otherwise, the string should just be echoed.
78 if (!*p) /* A single '-', so echo it. */
82 if (!strrchr("neE", *p))
86 /* All of the options in this arg are valid, so handle them. */
98 /* arg is already == *argv and isn't NULL */
102 /* optimization for very common case */
104 } else while ((c = *arg++)) {
105 if (c == eflag) { /* Check for escape seq. */
107 /* '\c' means cancel newline and
108 * ignore all subsequent chars. */
111 #if !ENABLE_FEATURE_FANCY_ECHO
112 /* SUSv3 specifies that octal escapes must begin with '0'. */
113 if ( (((unsigned char)*arg) - '1') >= 7)
116 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
117 * of the form \0### are accepted. */
118 if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
121 /* bb_process_escape_sequence can handle nul correctly */
122 c = bb_process_escape_sequence(&arg);
139 return fflush(stdout);
143 * Copyright (c) 1991, 1993
144 * The Regents of the University of California. All rights reserved.
146 * This code is derived from software contributed to Berkeley by
149 * Redistribution and use in source and binary forms, with or without
150 * modification, are permitted provided that the following conditions
152 * 1. Redistributions of source code must retain the above copyright
153 * notice, this list of conditions and the following disclaimer.
154 * 2. Redistributions in binary form must reproduce the above copyright
155 * notice, this list of conditions and the following disclaimer in the
156 * documentation and/or other materials provided with the distribution.
158 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
159 * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
161 * California, Berkeley and its contributors.
162 * 4. Neither the name of the University nor the names of its contributors
163 * may be used to endorse or promote products derived from this software
164 * without specific prior written permission.
166 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
167 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
168 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
169 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
170 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
171 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
172 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
173 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
174 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
175 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
178 * @(#)echo.c 8.1 (Berkeley) 5/31/93
181 #ifdef VERSION_WITH_WRITEV
182 /* We can't use stdio.
183 * The reason for this is highly non-obvious.
184 * echo_main is used from shell. Shell must correctly handle "echo foo"
185 * if stdout is closed. With stdio, output gets shoveled into
186 * stdout buffer, and even fflush cannot clear it out. It seems that
187 * even if libc receives EBADF on write attempts, it feels determined
188 * to output data no matter what. So it will try later,
189 * and possibly will clobber future output. Not good.
191 * Using writev instead, with 'direct' conversion of argv vector.
194 int echo_main(int argc, char **argv)
196 struct iovec io[argc];
197 struct iovec *cur_io = io;
200 #if !ENABLE_FEATURE_FANCY_ECHO
203 nflag = 1, /* 1 -- print '\n' */
219 /* If it appears that we are handling options, then make sure
220 * that all of the options specified are actually valid.
221 * Otherwise, the string should just be echoed.
224 if (!*p) /* A single '-', so echo it. */
228 if (!strrchr("neE", *p))
232 /* All of the options in this arg are valid, so handle them. */
245 /* arg is already == *argv and isn't NULL */
248 cur_io->iov_base = p = arg;
251 /* optimization for very common case */
253 } else while ((c = *arg++)) {
254 if (c == eflag) { /* Check for escape seq. */
256 /* '\c' means cancel newline and
257 * ignore all subsequent chars. */
258 cur_io->iov_len = p - (char*)cur_io->iov_base;
262 #if !ENABLE_FEATURE_FANCY_ECHO
263 /* SUSv3 specifies that octal escapes must begin with '0'. */
264 if ( (((unsigned char)*arg) - '1') >= 7)
267 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
268 * of the form \0### are accepted. */
269 if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
272 /* bb_process_escape_sequence can handle nul correctly */
273 c = bb_process_escape_sequence( (void*) &arg);
282 cur_io->iov_len = p - (char*)cur_io->iov_base;
290 cur_io->iov_base = (char*)"\n";
295 /* TODO: implement and use full_writev? */
296 return writev(1, io, (cur_io - io)) >= 0;