blob: 9663894ec824f5fc0478f67a418ddbd415d92461
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 | |
66 | int 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 | |
232 | int 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 |
333 |