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 ( (((unsigned char)*arg) - '1') >= 7)
114 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
115 * of the form \0### are accepted. */
116 if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
119 /* bb_process_escape_sequence can handle nul correctly */
120 c = bb_process_escape_sequence(&arg);
137 return fflush(stdout);
141 * Copyright (c) 1991, 1993
142 * The Regents of the University of California. All rights reserved.
144 * This code is derived from software contributed to Berkeley by
147 * Redistribution and use in source and binary forms, with or without
148 * modification, are permitted provided that the following conditions
150 * 1. Redistributions of source code must retain the above copyright
151 * notice, this list of conditions and the following disclaimer.
152 * 2. Redistributions in binary form must reproduce the above copyright
153 * notice, this list of conditions and the following disclaimer in the
154 * documentation and/or other materials provided with the distribution.
156 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
157 * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
159 * California, Berkeley and its contributors.
160 * 4. Neither the name of the University nor the names of its contributors
161 * may be used to endorse or promote products derived from this software
162 * without specific prior written permission.
164 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
165 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
166 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
167 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
168 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
169 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
170 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
171 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
172 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
173 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
176 * @(#)echo.c 8.1 (Berkeley) 5/31/93
179 #ifdef VERSION_WITH_WRITEV
180 /* We can't use stdio.
181 * The reason for this is highly non-obvious.
182 * echo_main is used from shell. Shell must correctly handle "echo foo"
183 * if stdout is closed. With stdio, output gets shoveled into
184 * stdout buffer, and even fflush cannot clear it out. It seems that
185 * even if libc receives EBADF on write attempts, it feels determined
186 * to output data no matter what. So it will try later,
187 * and possibly will clobber future output. Not good.
189 * Using writev instead, with 'direct' conversion of argv vector.
192 int echo_main(int argc, char **argv)
194 struct iovec io[argc];
195 struct iovec *cur_io = io;
198 #if !ENABLE_FEATURE_FANCY_ECHO
201 nflag = 1, /* 1 -- print '\n' */
217 /* If it appears that we are handling options, then make sure
218 * that all of the options specified are actually valid.
219 * Otherwise, the string should just be echoed.
222 if (!*p) /* A single '-', so echo it. */
226 if (!strrchr("neE", *p))
230 /* All of the options in this arg are valid, so handle them. */
243 /* arg is already == *argv and isn't NULL */
246 cur_io->iov_base = p = arg;
249 /* optimization for very common case */
251 } else while ((c = *arg++)) {
252 if (c == eflag) { /* Check for escape seq. */
254 /* '\c' means cancel newline and
255 * ignore all subsequent chars. */
256 cur_io->iov_len = p - (char*)cur_io->iov_base;
260 #if !ENABLE_FEATURE_FANCY_ECHO
261 /* SUSv3 specifies that octal escapes must begin with '0'. */
262 if ( (((unsigned char)*arg) - '1') >= 7)
265 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
266 * of the form \0### are accepted. */
267 if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
270 /* bb_process_escape_sequence can handle nul correctly */
271 c = bb_process_escape_sequence( (void*) &arg);
280 cur_io->iov_len = p - (char*)cur_io->iov_base;
288 cur_io->iov_base = (char*)"\n";
293 /* TODO: implement and use full_writev? */
294 return writev(1, io, (cur_io - io)) >= 0;