blob: fd0d9b780a0076f294c29c79df927b552ac130b3
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 | /* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org) |
13 | * |
14 | * Because of behavioral differences, implemented configurable SUSv3 |
15 | * or 'fancy' gnu-ish behaviors. Also, reduced size and fixed bugs. |
16 | * 1) In handling '\c' escape, the previous version only suppressed the |
17 | * trailing newline. SUSv3 specifies _no_ output after '\c'. |
18 | * 2) SUSv3 specifies that octal escapes are of the form \0{#{#{#}}}. |
19 | * The previous version did not allow 4-digit octals. |
20 | */ |
21 | //config:config ECHO |
22 | //config: bool "echo (basic SuSv3 version taking no options)" |
23 | //config: default y |
24 | //config: help |
25 | //config: echo is used to print a specified string to stdout. |
26 | //config: |
27 | //config:# this entry also appears in shell/Config.in, next to the echo builtin |
28 | //config:config FEATURE_FANCY_ECHO |
29 | //config: bool "Enable echo options (-n and -e)" |
30 | //config: default y |
31 | //config: depends on ECHO || ASH_BUILTIN_ECHO || HUSH |
32 | //config: help |
33 | //config: This adds options (-n and -e) to echo. |
34 | |
35 | //applet:IF_ECHO(APPLET_NOFORK(echo, echo, BB_DIR_BIN, BB_SUID_DROP, echo)) |
36 | |
37 | //kbuild:lib-$(CONFIG_ECHO) += echo.o |
38 | |
39 | /* BB_AUDIT SUSv3 compliant -- unless configured as fancy echo. */ |
40 | /* http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html */ |
41 | |
42 | //usage:#define echo_trivial_usage |
43 | //usage: IF_FEATURE_FANCY_ECHO("[-neE] ") "[ARG]..." |
44 | //usage:#define echo_full_usage "\n\n" |
45 | //usage: "Print the specified ARGs to stdout" |
46 | //usage: IF_FEATURE_FANCY_ECHO( "\n" |
47 | //usage: "\n -n Suppress trailing newline" |
48 | //usage: "\n -e Interpret backslash escapes (i.e., \\t=tab)" |
49 | //usage: "\n -E Don't interpret backslash escapes (default)" |
50 | //usage: ) |
51 | //usage: |
52 | //usage:#define echo_example_usage |
53 | //usage: "$ echo \"Erik is cool\"\n" |
54 | //usage: "Erik is cool\n" |
55 | //usage: IF_FEATURE_FANCY_ECHO("$ echo -e \"Erik\\nis\\ncool\"\n" |
56 | //usage: "Erik\n" |
57 | //usage: "is\n" |
58 | //usage: "cool\n" |
59 | //usage: "$ echo \"Erik\\nis\\ncool\"\n" |
60 | //usage: "Erik\\nis\\ncool\n") |
61 | |
62 | #include "libbb.h" |
63 | |
64 | /* This is a NOFORK applet. Be very careful! */ |
65 | |
66 | /* NB: can be used by shell even if not enabled as applet */ |
67 | |
68 | /* |
69 | * NB2: we don't use stdio, we need better error handing. |
70 | * Examples include writing into non-opened stdout and error on write. |
71 | * |
72 | * With stdio, output gets shoveled into stdout buffer, and even |
73 | * fflush cannot clear it out. It seems that even if libc receives |
74 | * EBADF on write attempts, it feels determined to output data no matter what. |
75 | * If echo is called by shell, it will try writing again later, and possibly |
76 | * will clobber future output. Not good. |
77 | * |
78 | * Solaris has fpurge which discards buffered input. glibc has __fpurge. |
79 | * But this function is not standard. |
80 | */ |
81 | |
82 | int echo_main(int argc UNUSED_PARAM, char **argv) |
83 | { |
84 | char **pp; |
85 | const char *arg; |
86 | char *out; |
87 | char *buffer; |
88 | unsigned buflen; |
89 | #if !ENABLE_FEATURE_FANCY_ECHO |
90 | enum { |
91 | eflag = 0, /* 0 -- disable escape sequences */ |
92 | nflag = 1, /* 1 -- print '\n' */ |
93 | }; |
94 | |
95 | argv++; |
96 | #else |
97 | char nflag = 1; |
98 | char eflag = 0; |
99 | |
100 | while ((arg = *++argv) != NULL) { |
101 | char n, e; |
102 | |
103 | if (arg[0] != '-') |
104 | break; /* not an option arg, echo it */ |
105 | |
106 | /* If it appears that we are handling options, then make sure |
107 | * that all of the options specified are actually valid. |
108 | * Otherwise, the string should just be echoed. |
109 | */ |
110 | arg++; |
111 | n = nflag; |
112 | e = eflag; |
113 | do { |
114 | if (*arg == 'n') |
115 | n = 0; |
116 | else if (*arg == 'e') |
117 | e = '\\'; |
118 | else if (*arg != 'E') { |
119 | /* "-ccc" arg with one of c's invalid, echo it */ |
120 | /* arg consisting from just "-" also handled here */ |
121 | goto just_echo; |
122 | } |
123 | } while (*++arg); |
124 | nflag = n; |
125 | eflag = e; |
126 | } |
127 | just_echo: |
128 | #endif |
129 | |
130 | buflen = 0; |
131 | pp = argv; |
132 | while ((arg = *pp) != NULL) { |
133 | buflen += strlen(arg) + 1; |
134 | pp++; |
135 | } |
136 | out = buffer = xmalloc(buflen + 1); /* +1 is needed for "no args" case */ |
137 | |
138 | while ((arg = *argv) != NULL) { |
139 | int c; |
140 | |
141 | if (!eflag) { |
142 | /* optimization for very common case */ |
143 | out = stpcpy(out, arg); |
144 | } else |
145 | while ((c = *arg++) != '\0') { |
146 | if (c == eflag) { |
147 | /* This is an "\x" sequence */ |
148 | |
149 | if (*arg == 'c') { |
150 | /* "\c" means cancel newline and |
151 | * ignore all subsequent chars. */ |
152 | goto do_write; |
153 | } |
154 | /* Since SUSv3 mandates a first digit of 0, 4-digit octals |
155 | * of the form \0### are accepted. */ |
156 | if (*arg == '0') { |
157 | if ((unsigned char)(arg[1] - '0') < 8) { |
158 | /* 2nd char is 0..7: skip leading '0' */ |
159 | arg++; |
160 | } |
161 | } |
162 | /* bb_process_escape_sequence handles NUL correctly |
163 | * ("...\" case). */ |
164 | { |
165 | /* optimization: don't force arg to be on-stack, |
166 | * use another variable for that. ~30 bytes win */ |
167 | const char *z = arg; |
168 | c = bb_process_escape_sequence(&z); |
169 | arg = z; |
170 | } |
171 | } |
172 | *out++ = c; |
173 | } |
174 | |
175 | if (!*++argv) |
176 | break; |
177 | *out++ = ' '; |
178 | } |
179 | |
180 | if (nflag) { |
181 | *out++ = '\n'; |
182 | } |
183 | |
184 | do_write: |
185 | /* Careful to error out on partial writes too (think ENOSPC!) */ |
186 | errno = 0; |
187 | /*r =*/ full_write(STDOUT_FILENO, buffer, out - buffer); |
188 | free(buffer); |
189 | if (/*WRONG:r < 0*/ errno) { |
190 | bb_perror_msg(bb_msg_write_error); |
191 | return 1; |
192 | } |
193 | return 0; |
194 | } |
195 | |
196 | /* |
197 | * Copyright (c) 1991, 1993 |
198 | * The Regents of the University of California. All rights reserved. |
199 | * |
200 | * This code is derived from software contributed to Berkeley by |
201 | * Kenneth Almquist. |
202 | * |
203 | * Redistribution and use in source and binary forms, with or without |
204 | * modification, are permitted provided that the following conditions |
205 | * are met: |
206 | * 1. Redistributions of source code must retain the above copyright |
207 | * notice, this list of conditions and the following disclaimer. |
208 | * 2. Redistributions in binary form must reproduce the above copyright |
209 | * notice, this list of conditions and the following disclaimer in the |
210 | * documentation and/or other materials provided with the distribution. |
211 | * |
212 | * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change |
213 | * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change> |
214 | * |
215 | * California, Berkeley and its contributors. |
216 | * 4. Neither the name of the University nor the names of its contributors |
217 | * may be used to endorse or promote products derived from this software |
218 | * without specific prior written permission. |
219 | * |
220 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
221 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
222 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
223 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
224 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
225 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
226 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
227 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
228 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
229 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
230 | * SUCH DAMAGE. |
231 | * |
232 | * @(#)echo.c 8.1 (Berkeley) 5/31/93 |
233 | */ |
234 | |
235 | #ifdef VERSION_WITH_WRITEV |
236 | /* We can't use stdio. |
237 | * The reason for this is highly non-obvious. |
238 | * echo_main is used from shell. Shell must correctly handle "echo foo" |
239 | * if stdout is closed. With stdio, output gets shoveled into |
240 | * stdout buffer, and even fflush cannot clear it out. It seems that |
241 | * even if libc receives EBADF on write attempts, it feels determined |
242 | * to output data no matter what. So it will try later, |
243 | * and possibly will clobber future output. Not good. |
244 | * |
245 | * Using writev instead, with 'direct' conversion of argv vector. |
246 | */ |
247 | |
248 | int echo_main(int argc, char **argv) |
249 | { |
250 | struct iovec io[argc]; |
251 | struct iovec *cur_io = io; |
252 | char *arg; |
253 | char *p; |
254 | #if !ENABLE_FEATURE_FANCY_ECHO |
255 | enum { |
256 | eflag = '\\', |
257 | nflag = 1, /* 1 -- print '\n' */ |
258 | }; |
259 | arg = *++argv; |
260 | if (!arg) |
261 | goto newline_ret; |
262 | #else |
263 | char nflag = 1; |
264 | char eflag = 0; |
265 | |
266 | while (1) { |
267 | arg = *++argv; |
268 | if (!arg) |
269 | goto newline_ret; |
270 | if (*arg != '-') |
271 | break; |
272 | |
273 | /* If it appears that we are handling options, then make sure |
274 | * that all of the options specified are actually valid. |
275 | * Otherwise, the string should just be echoed. |
276 | */ |
277 | p = arg + 1; |
278 | if (!*p) /* A single '-', so echo it. */ |
279 | goto just_echo; |
280 | |
281 | do { |
282 | if (!strchr("neE", *p)) |
283 | goto just_echo; |
284 | } while (*++p); |
285 | |
286 | /* All of the options in this arg are valid, so handle them. */ |
287 | p = arg + 1; |
288 | do { |
289 | if (*p == 'n') |
290 | nflag = 0; |
291 | if (*p == 'e') |
292 | eflag = '\\'; |
293 | } while (*++p); |
294 | } |
295 | just_echo: |
296 | #endif |
297 | |
298 | while (1) { |
299 | /* arg is already == *argv and isn't NULL */ |
300 | int c; |
301 | |
302 | cur_io->iov_base = p = arg; |
303 | |
304 | if (!eflag) { |
305 | /* optimization for very common case */ |
306 | p += strlen(arg); |
307 | } else while ((c = *arg++)) { |
308 | if (c == eflag) { |
309 | /* This is an "\x" sequence */ |
310 | |
311 | if (*arg == 'c') { |
312 | /* "\c" means cancel newline and |
313 | * ignore all subsequent chars. */ |
314 | cur_io->iov_len = p - (char*)cur_io->iov_base; |
315 | cur_io++; |
316 | goto ret; |
317 | } |
318 | /* Since SUSv3 mandates a first digit of 0, 4-digit octals |
319 | * of the form \0### are accepted. */ |
320 | if (*arg == '0' && (unsigned char)(arg[1] - '0') < 8) { |
321 | arg++; |
322 | } |
323 | /* bb_process_escape_sequence can handle nul correctly */ |
324 | c = bb_process_escape_sequence( (void*) &arg); |
325 | } |
326 | *p++ = c; |
327 | } |
328 | |
329 | arg = *++argv; |
330 | if (arg) |
331 | *p++ = ' '; |
332 | cur_io->iov_len = p - (char*)cur_io->iov_base; |
333 | cur_io++; |
334 | if (!arg) |
335 | break; |
336 | } |
337 | |
338 | newline_ret: |
339 | if (nflag) { |
340 | cur_io->iov_base = (char*)"\n"; |
341 | cur_io->iov_len = 1; |
342 | cur_io++; |
343 | } |
344 | ret: |
345 | /* TODO: implement and use full_writev? */ |
346 | return writev(1, io, (cur_io - io)) >= 0; |
347 | } |
348 | #endif |
349 |