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.
26 //usage:#define echo_trivial_usage
27 //usage: IF_FEATURE_FANCY_ECHO("[-neE] ") "[ARG]..."
28 //usage:#define echo_full_usage "\n\n"
29 //usage: "Print the specified ARGs to stdout"
30 //usage: IF_FEATURE_FANCY_ECHO( "\n"
32 //usage: "\n -n Suppress trailing newline"
33 //usage: "\n -e Interpret backslash escapes (i.e., \\t=tab)"
34 //usage: "\n -E Don't interpret backslash escapes (default)"
37 //usage:#define echo_example_usage
38 //usage: "$ echo \"Erik is cool\"\n"
39 //usage: "Erik is cool\n"
40 //usage: IF_FEATURE_FANCY_ECHO("$ echo -e \"Erik\\nis\\ncool\"\n"
44 //usage: "$ echo \"Erik\\nis\\ncool\"\n"
45 //usage: "Erik\\nis\\ncool\n")
49 /* This is a NOFORK applet. Be very careful! */
51 /* NB: can be used by shell even if not enabled as applet */
54 * NB2: we don't use stdio, we need better error handing.
55 * Examples include writing into non-opened stdout and error on write.
57 * With stdio, output gets shoveled into stdout buffer, and even
58 * fflush cannot clear it out. It seems that even if libc receives
59 * EBADF on write attempts, it feels determined to output data no matter what.
60 * If echo is called by shell, it will try writing again later, and possibly
61 * will clobber future output. Not good.
63 * Solaris has fpurge which discards buffered input. glibc has __fpurge.
64 * But this function is not standard.
67 int echo_main(int argc UNUSED_PARAM, char **argv)
74 #if !ENABLE_FEATURE_FANCY_ECHO
77 nflag = 1, /* 1 -- print '\n' */
85 while ((arg = *++argv) != NULL) {
89 break; /* not an option arg, echo it */
91 /* If it appears that we are handling options, then make sure
92 * that all of the options specified are actually valid.
93 * Otherwise, the string should just be echoed.
101 else if (*arg == 'e')
103 else if (*arg != 'E') {
104 /* "-ccc" arg with one of c's invalid, echo it */
105 /* arg consisting from just "-" also handled here */
117 while ((arg = *pp) != NULL) {
118 buflen += strlen(arg) + 1;
121 out = buffer = xmalloc(buflen + 1); /* +1 is needed for "no args" case */
123 while ((arg = *argv) != NULL) {
127 /* optimization for very common case */
128 out = stpcpy(out, arg);
130 while ((c = *arg++) != '\0') {
132 /* This is an "\x" sequence */
135 /* "\c" means cancel newline and
136 * ignore all subsequent chars. */
139 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
140 * of the form \0### are accepted. */
142 if ((unsigned char)(arg[1] - '0') < 8) {
143 /* 2nd char is 0..7: skip leading '0' */
147 /* bb_process_escape_sequence handles NUL correctly
150 /* optimization: don't force arg to be on-stack,
151 * use another variable for that. ~30 bytes win */
153 c = bb_process_escape_sequence(&z);
170 /* Careful to error out on partial writes too (think ENOSPC!) */
172 /*r =*/ full_write(STDOUT_FILENO, buffer, out - buffer);
174 if (/*WRONG:r < 0*/ errno) {
175 bb_perror_msg(bb_msg_write_error);
182 * Copyright (c) 1991, 1993
183 * The Regents of the University of California. All rights reserved.
185 * This code is derived from software contributed to Berkeley by
188 * Redistribution and use in source and binary forms, with or without
189 * modification, are permitted provided that the following conditions
191 * 1. Redistributions of source code must retain the above copyright
192 * notice, this list of conditions and the following disclaimer.
193 * 2. Redistributions in binary form must reproduce the above copyright
194 * notice, this list of conditions and the following disclaimer in the
195 * documentation and/or other materials provided with the distribution.
197 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
198 * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
200 * California, Berkeley and its contributors.
201 * 4. Neither the name of the University nor the names of its contributors
202 * may be used to endorse or promote products derived from this software
203 * without specific prior written permission.
205 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
206 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
207 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
208 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
209 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
210 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
211 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
212 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
213 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
214 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
217 * @(#)echo.c 8.1 (Berkeley) 5/31/93
220 #ifdef VERSION_WITH_WRITEV
221 /* We can't use stdio.
222 * The reason for this is highly non-obvious.
223 * echo_main is used from shell. Shell must correctly handle "echo foo"
224 * if stdout is closed. With stdio, output gets shoveled into
225 * stdout buffer, and even fflush cannot clear it out. It seems that
226 * even if libc receives EBADF on write attempts, it feels determined
227 * to output data no matter what. So it will try later,
228 * and possibly will clobber future output. Not good.
230 * Using writev instead, with 'direct' conversion of argv vector.
233 int echo_main(int argc, char **argv)
235 struct iovec io[argc];
236 struct iovec *cur_io = io;
239 #if !ENABLE_FEATURE_FANCY_ECHO
242 nflag = 1, /* 1 -- print '\n' */
258 /* If it appears that we are handling options, then make sure
259 * that all of the options specified are actually valid.
260 * Otherwise, the string should just be echoed.
263 if (!*p) /* A single '-', so echo it. */
267 if (!strchr("neE", *p))
271 /* All of the options in this arg are valid, so handle them. */
284 /* arg is already == *argv and isn't NULL */
287 cur_io->iov_base = p = arg;
290 /* optimization for very common case */
292 } else while ((c = *arg++)) {
294 /* This is an "\x" sequence */
297 /* "\c" means cancel newline and
298 * ignore all subsequent chars. */
299 cur_io->iov_len = p - (char*)cur_io->iov_base;
303 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
304 * of the form \0### are accepted. */
305 if (*arg == '0' && (unsigned char)(arg[1] - '0') < 8) {
308 /* bb_process_escape_sequence can handle nul correctly */
309 c = bb_process_escape_sequence( (void*) &arg);
317 cur_io->iov_len = p - (char*)cur_io->iov_base;
325 cur_io->iov_base = (char*)"\n";
330 /* TODO: implement and use full_writev? */
331 return writev(1, io, (cur_io - io)) >= 0;