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 /* NB: can be used by shell even if not enabled as applet */
32 int echo_main(int argc ATTRIBUTE_UNUSED, char **argv)
35 #if !ENABLE_FEATURE_FANCY_ECHO
38 nflag = 1, /* 1 -- print '\n' */
41 /* We must check that stdout is not closed.
42 * The reason for this is highly non-obvious.
43 * echo_main is used from shell. Shell must correctly handle "echo foo"
44 * if stdout is closed. With stdio, output gets shoveled into
45 * stdout buffer, and even fflush cannot clear it out. It seems that
46 * even if libc receives EBADF on write attempts, it feels determined
47 * to output data no matter what. So it will try later,
48 * and possibly will clobber future output. Not good. */
60 /* We must check that stdout is not closed. */
71 /* If it appears that we are handling options, then make sure
72 * that all of the options specified are actually valid.
73 * Otherwise, the string should just be echoed.
76 if (!*p) /* A single '-', so echo it. */
80 if (!strrchr("neE", *p))
84 /* All of the options in this arg are valid, so handle them. */
96 /* arg is already == *argv and isn't NULL */
100 /* optimization for very common case */
102 } else while ((c = *arg++)) {
103 if (c == eflag) { /* Check for escape seq. */
105 /* '\c' means cancel newline and
106 * ignore all subsequent chars. */
109 #if !ENABLE_FEATURE_FANCY_ECHO
110 /* SUSv3 specifies that octal escapes must begin with '0'. */
111 if ( ((int)(unsigned char)(*arg) - '0') >= 8) /* '8' or bigger */
114 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
115 * of the form \0### are accepted. */
117 /* NB: don't turn "...\0" into "...\" */
118 if (arg[1] && ((unsigned char)(arg[1]) - '0') < 8) {
122 /* bb_process_escape_sequence handles NUL correctly
124 c = bb_process_escape_sequence(&arg);
141 return fflush(stdout);
145 * Copyright (c) 1991, 1993
146 * The Regents of the University of California. All rights reserved.
148 * This code is derived from software contributed to Berkeley by
151 * Redistribution and use in source and binary forms, with or without
152 * modification, are permitted provided that the following conditions
154 * 1. Redistributions of source code must retain the above copyright
155 * notice, this list of conditions and the following disclaimer.
156 * 2. Redistributions in binary form must reproduce the above copyright
157 * notice, this list of conditions and the following disclaimer in the
158 * documentation and/or other materials provided with the distribution.
160 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
161 * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
163 * California, Berkeley and its contributors.
164 * 4. Neither the name of the University nor the names of its contributors
165 * may be used to endorse or promote products derived from this software
166 * without specific prior written permission.
168 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
169 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
170 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
171 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
172 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
173 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
174 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
175 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
176 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
177 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
180 * @(#)echo.c 8.1 (Berkeley) 5/31/93
183 #ifdef VERSION_WITH_WRITEV
184 /* We can't use stdio.
185 * The reason for this is highly non-obvious.
186 * echo_main is used from shell. Shell must correctly handle "echo foo"
187 * if stdout is closed. With stdio, output gets shoveled into
188 * stdout buffer, and even fflush cannot clear it out. It seems that
189 * even if libc receives EBADF on write attempts, it feels determined
190 * to output data no matter what. So it will try later,
191 * and possibly will clobber future output. Not good.
193 * Using writev instead, with 'direct' conversion of argv vector.
196 int echo_main(int argc, char **argv)
198 struct iovec io[argc];
199 struct iovec *cur_io = io;
202 #if !ENABLE_FEATURE_FANCY_ECHO
205 nflag = 1, /* 1 -- print '\n' */
221 /* If it appears that we are handling options, then make sure
222 * that all of the options specified are actually valid.
223 * Otherwise, the string should just be echoed.
226 if (!*p) /* A single '-', so echo it. */
230 if (!strrchr("neE", *p))
234 /* All of the options in this arg are valid, so handle them. */
247 /* arg is already == *argv and isn't NULL */
250 cur_io->iov_base = p = arg;
253 /* optimization for very common case */
255 } else while ((c = *arg++)) {
256 if (c == eflag) { /* Check for escape seq. */
258 /* '\c' means cancel newline and
259 * ignore all subsequent chars. */
260 cur_io->iov_len = p - (char*)cur_io->iov_base;
264 #if !ENABLE_FEATURE_FANCY_ECHO
265 /* SUSv3 specifies that octal escapes must begin with '0'. */
266 if ( (((unsigned char)*arg) - '1') >= 7)
269 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
270 * of the form \0### are accepted. */
271 if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
274 /* bb_process_escape_sequence can handle nul correctly */
275 c = bb_process_escape_sequence( (void*) &arg);
284 cur_io->iov_len = p - (char*)cur_io->iov_base;
292 cur_io->iov_base = (char*)"\n";
297 /* TODO: implement and use full_writev? */
298 return writev(1, io, (cur_io - io)) >= 0;