source: branches/3.2/mindi-busybox/coreutils/echo.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
File size: 9.0 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * echo implementation for busybox
4 *
5 * Copyright (c) 1991, 1993
6 *  The Regents of the University of California.  All rights reserved.
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 *
10 * Original copyright notice is retained at the end of this file.
11 */
12
13/* BB_AUDIT SUSv3 compliant -- unless configured as fancy echo. */
14/* http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html */
15
16/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
17 *
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.
24 */
25
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"
31//usage:     "\n    -n  Suppress trailing newline"
32//usage:     "\n    -e  Interpret backslash escapes (i.e., \\t=tab)"
33//usage:     "\n    -E  Don't interpret backslash escapes (default)"
34//usage:    )
35//usage:
36//usage:#define echo_example_usage
37//usage:       "$ echo \"Erik is cool\"\n"
38//usage:       "Erik is cool\n"
39//usage:    IF_FEATURE_FANCY_ECHO("$ echo -e \"Erik\\nis\\ncool\"\n"
40//usage:       "Erik\n"
41//usage:       "is\n"
42//usage:       "cool\n"
43//usage:       "$ echo \"Erik\\nis\\ncool\"\n"
44//usage:       "Erik\\nis\\ncool\n")
45
46#include "libbb.h"
47
48/* This is a NOFORK applet. Be very careful! */
49
50/* NB: can be used by shell even if not enabled as applet */
51
52/*
53 * NB2: we don't use stdio, we need better error handing.
54 * Examples include writing into non-opened stdout and error on write.
55 *
56 * With stdio, output gets shoveled into stdout buffer, and even
57 * fflush cannot clear it out. It seems that even if libc receives
58 * EBADF on write attempts, it feels determined to output data no matter what.
59 * If echo is called by shell, it will try writing again later, and possibly
60 * will clobber future output. Not good.
61 *
62 * Solaris has fpurge which discards buffered input. glibc has __fpurge.
63 * But this function is not standard.
64 */
65
66int echo_main(int argc UNUSED_PARAM, char **argv)
67{
68    char **pp;
69    const char *arg;
70    char *out;
71    char *buffer;
72    unsigned buflen;
73#if !ENABLE_FEATURE_FANCY_ECHO
74    enum {
75        eflag = '\\',
76        nflag = 1,  /* 1 -- print '\n' */
77    };
78
79    argv++;
80#else
81    char nflag = 1;
82    char eflag = 0;
83
84    while ((arg = *++argv) != NULL) {
85        char n, e;
86
87        if (arg[0] != '-')
88            break; /* not an option arg, echo it */
89
90        /* If it appears that we are handling options, then make sure
91         * that all of the options specified are actually valid.
92         * Otherwise, the string should just be echoed.
93         */
94        arg++;
95        n = nflag;
96        e = eflag;
97        do {
98            if (*arg == 'n')
99                n = 0;
100            else if (*arg == 'e')
101                e = '\\';
102            else if (*arg != 'E') {
103                /* "-ccc" arg with one of c's invalid, echo it */
104                /* arg consisting from just "-" also handled here */
105                goto just_echo;
106            }
107        } while (*++arg);
108        nflag = n;
109        eflag = e;
110    }
111 just_echo:
112#endif
113
114    buflen = 0;
115    pp = argv;
116    while ((arg = *pp) != NULL) {
117        buflen += strlen(arg) + 1;
118        pp++;
119    }
120    out = buffer = xmalloc(buflen + 1); /* +1 is needed for "no args" case */
121
122    while ((arg = *argv) != NULL) {
123        int c;
124
125        if (!eflag) {
126            /* optimization for very common case */
127            out = stpcpy(out, arg);
128        } else
129        while ((c = *arg++) != '\0') {
130            if (c == eflag) {
131                /* This is an "\x" sequence */
132
133                if (*arg == 'c') {
134                    /* "\c" means cancel newline and
135                     * ignore all subsequent chars. */
136                    goto do_write;
137                }
138                /* Since SUSv3 mandates a first digit of 0, 4-digit octals
139                * of the form \0### are accepted. */
140                if (*arg == '0') {
141                    if ((unsigned char)(arg[1] - '0') < 8) {
142                        /* 2nd char is 0..7: skip leading '0' */
143                        arg++;
144                    }
145                }
146                /* bb_process_escape_sequence handles NUL correctly
147                 * ("...\" case). */
148                {
149                    /* optimization: don't force arg to be on-stack,
150                     * use another variable for that. ~30 bytes win */
151                    const char *z = arg;
152                    c = bb_process_escape_sequence(&z);
153                    arg = z;
154                }
155            }
156            *out++ = c;
157        }
158
159        if (!*++argv)
160            break;
161        *out++ = ' ';
162    }
163
164    if (nflag) {
165        *out++ = '\n';
166    }
167
168 do_write:
169    /* Careful to error out on partial writes too (think ENOSPC!) */
170    errno = 0;
171    /*r =*/ full_write(STDOUT_FILENO, buffer, out - buffer);
172    free(buffer);
173    if (/*WRONG:r < 0*/ errno) {
174        bb_perror_msg(bb_msg_write_error);
175        return 1;
176    }
177    return 0;
178}
179
180/*
181 * Copyright (c) 1991, 1993
182 *  The Regents of the University of California.  All rights reserved.
183 *
184 * This code is derived from software contributed to Berkeley by
185 * Kenneth Almquist.
186 *
187 * Redistribution and use in source and binary forms, with or without
188 * modification, are permitted provided that the following conditions
189 * are met:
190 * 1. Redistributions of source code must retain the above copyright
191 *    notice, this list of conditions and the following disclaimer.
192 * 2. Redistributions in binary form must reproduce the above copyright
193 *    notice, this list of conditions and the following disclaimer in the
194 *    documentation and/or other materials provided with the distribution.
195 *
196 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
197 *      ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
198 *
199 *  California, Berkeley and its contributors.
200 * 4. Neither the name of the University nor the names of its contributors
201 *    may be used to endorse or promote products derived from this software
202 *    without specific prior written permission.
203 *
204 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
205 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
206 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
207 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
208 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
209 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
210 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
211 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
212 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
213 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
214 * SUCH DAMAGE.
215 *
216 *  @(#)echo.c  8.1 (Berkeley) 5/31/93
217 */
218
219#ifdef VERSION_WITH_WRITEV
220/* We can't use stdio.
221 * The reason for this is highly non-obvious.
222 * echo_main is used from shell. Shell must correctly handle "echo foo"
223 * if stdout is closed. With stdio, output gets shoveled into
224 * stdout buffer, and even fflush cannot clear it out. It seems that
225 * even if libc receives EBADF on write attempts, it feels determined
226 * to output data no matter what. So it will try later,
227 * and possibly will clobber future output. Not good.
228 *
229 * Using writev instead, with 'direct' conversion of argv vector.
230 */
231
232int echo_main(int argc, char **argv)
233{
234    struct iovec io[argc];
235    struct iovec *cur_io = io;
236    char *arg;
237    char *p;
238#if !ENABLE_FEATURE_FANCY_ECHO
239    enum {
240        eflag = '\\',
241        nflag = 1,  /* 1 -- print '\n' */
242    };
243    arg = *++argv;
244    if (!arg)
245        goto newline_ret;
246#else
247    char nflag = 1;
248    char eflag = 0;
249
250    while (1) {
251        arg = *++argv;
252        if (!arg)
253            goto newline_ret;
254        if (*arg != '-')
255            break;
256
257        /* If it appears that we are handling options, then make sure
258         * that all of the options specified are actually valid.
259         * Otherwise, the string should just be echoed.
260         */
261        p = arg + 1;
262        if (!*p)    /* A single '-', so echo it. */
263            goto just_echo;
264
265        do {
266            if (!strchr("neE", *p))
267                goto just_echo;
268        } while (*++p);
269
270        /* All of the options in this arg are valid, so handle them. */
271        p = arg + 1;
272        do {
273            if (*p == 'n')
274                nflag = 0;
275            if (*p == 'e')
276                eflag = '\\';
277        } while (*++p);
278    }
279 just_echo:
280#endif
281
282    while (1) {
283        /* arg is already == *argv and isn't NULL */
284        int c;
285
286        cur_io->iov_base = p = arg;
287
288        if (!eflag) {
289            /* optimization for very common case */
290            p += strlen(arg);
291        } else while ((c = *arg++)) {
292            if (c == eflag) {
293                /* This is an "\x" sequence */
294
295                if (*arg == 'c') {
296                    /* "\c" means cancel newline and
297                     * ignore all subsequent chars. */
298                    cur_io->iov_len = p - (char*)cur_io->iov_base;
299                    cur_io++;
300                    goto ret;
301                }
302                /* Since SUSv3 mandates a first digit of 0, 4-digit octals
303                * of the form \0### are accepted. */
304                if (*arg == '0' && (unsigned char)(arg[1] - '0') < 8) {
305                    arg++;
306                }
307                /* bb_process_escape_sequence can handle nul correctly */
308                c = bb_process_escape_sequence( (void*) &arg);
309            }
310            *p++ = c;
311        }
312
313        arg = *++argv;
314        if (arg)
315            *p++ = ' ';
316        cur_io->iov_len = p - (char*)cur_io->iov_base;
317        cur_io++;
318        if (!arg)
319            break;
320    }
321
322 newline_ret:
323    if (nflag) {
324        cur_io->iov_base = (char*)"\n";
325        cur_io->iov_len = 1;
326        cur_io++;
327    }
328 ret:
329    /* TODO: implement and use full_writev? */
330    return writev(1, io, (cur_io - io)) >= 0;
331}
332#endif
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