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 source tree.
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 */
33 * NB2: we don't use stdio, we need better error handing.
34 * Examples include writing into non-opened stdout and error on write.
36 * With stdio, output gets shoveled into stdout buffer, and even
37 * fflush cannot clear it out. It seems that even if libc receives
38 * EBADF on write attempts, it feels determined to output data no matter what.
39 * If echo is called by shell, it will try writing again later, and possibly
40 * will clobber future output. Not good.
42 * Solaris has fpurge which discards buffered input. glibc has __fpurge.
43 * But this function is not standard.
46 int echo_main(int argc UNUSED_PARAM, char **argv)
53 #if !ENABLE_FEATURE_FANCY_ECHO
56 nflag = 1, /* 1 -- print '\n' */
64 while ((arg = *++argv) != NULL) {
68 break; /* not an option arg, echo it */
70 /* If it appears that we are handling options, then make sure
71 * that all of the options specified are actually valid.
72 * Otherwise, the string should just be echoed.
82 else if (*arg != 'E') {
83 /* "-ccc" arg with one of c's invalid, echo it */
84 /* arg consisting from just "-" also handled here */
96 while ((arg = *pp) != NULL) {
97 buflen += strlen(arg) + 1;
100 out = buffer = xmalloc(buflen + 1); /* +1 is needed for "no args" case */
102 while ((arg = *argv) != NULL) {
106 /* optimization for very common case */
107 out = stpcpy(out, arg);
109 while ((c = *arg++) != '\0') {
111 /* This is an "\x" sequence */
114 /* "\c" means cancel newline and
115 * ignore all subsequent chars. */
118 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
119 * of the form \0### are accepted. */
121 if ((unsigned char)(arg[1] - '0') < 8) {
122 /* 2nd char is 0..7: skip leading '0' */
126 /* bb_process_escape_sequence handles NUL correctly
129 /* optimization: don't force arg to be on-stack,
130 * use another variable for that. ~30 bytes win */
132 c = bb_process_escape_sequence(&z);
149 /* Careful to error out on partial writes too (think ENOSPC!) */
151 /*r =*/ full_write(STDOUT_FILENO, buffer, out - buffer);
153 if (/*WRONG:r < 0*/ errno) {
154 bb_perror_msg(bb_msg_write_error);
161 * Copyright (c) 1991, 1993
162 * The Regents of the University of California. All rights reserved.
164 * This code is derived from software contributed to Berkeley by
167 * Redistribution and use in source and binary forms, with or without
168 * modification, are permitted provided that the following conditions
170 * 1. Redistributions of source code must retain the above copyright
171 * notice, this list of conditions and the following disclaimer.
172 * 2. Redistributions in binary form must reproduce the above copyright
173 * notice, this list of conditions and the following disclaimer in the
174 * documentation and/or other materials provided with the distribution.
176 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
177 * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
179 * California, Berkeley and its contributors.
180 * 4. Neither the name of the University nor the names of its contributors
181 * may be used to endorse or promote products derived from this software
182 * without specific prior written permission.
184 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
185 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
186 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
187 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
188 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
189 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
190 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
191 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
192 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
193 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
196 * @(#)echo.c 8.1 (Berkeley) 5/31/93
199 #ifdef VERSION_WITH_WRITEV
200 /* We can't use stdio.
201 * The reason for this is highly non-obvious.
202 * echo_main is used from shell. Shell must correctly handle "echo foo"
203 * if stdout is closed. With stdio, output gets shoveled into
204 * stdout buffer, and even fflush cannot clear it out. It seems that
205 * even if libc receives EBADF on write attempts, it feels determined
206 * to output data no matter what. So it will try later,
207 * and possibly will clobber future output. Not good.
209 * Using writev instead, with 'direct' conversion of argv vector.
212 int echo_main(int argc, char **argv)
214 struct iovec io[argc];
215 struct iovec *cur_io = io;
218 #if !ENABLE_FEATURE_FANCY_ECHO
221 nflag = 1, /* 1 -- print '\n' */
237 /* If it appears that we are handling options, then make sure
238 * that all of the options specified are actually valid.
239 * Otherwise, the string should just be echoed.
242 if (!*p) /* A single '-', so echo it. */
246 if (!strchr("neE", *p))
250 /* All of the options in this arg are valid, so handle them. */
263 /* arg is already == *argv and isn't NULL */
266 cur_io->iov_base = p = arg;
269 /* optimization for very common case */
271 } else while ((c = *arg++)) {
273 /* This is an "\x" sequence */
276 /* "\c" means cancel newline and
277 * ignore all subsequent chars. */
278 cur_io->iov_len = p - (char*)cur_io->iov_base;
282 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
283 * of the form \0### are accepted. */
284 if (*arg == '0' && (unsigned char)(arg[1] - '0') < 8) {
287 /* bb_process_escape_sequence can handle nul correctly */
288 c = bb_process_escape_sequence( (void*) &arg);
296 cur_io->iov_len = p - (char*)cur_io->iov_base;
304 cur_io->iov_base = (char*)"\n";
309 /* TODO: implement and use full_writev? */
310 return writev(1, io, (cur_io - io)) >= 0;