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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
b5efdb8a | 22 | #include "alloc-util.h" |
e4e73a63 LP |
23 | #include "escape.h" |
24 | #include "hexdecoct.h" | |
4f5dd394 LP |
25 | #include "utf8.h" |
26 | #include "util.h" | |
27 | ||
4f5dd394 LP |
28 | size_t cescape_char(char c, char *buf) { |
29 | char * buf_old = buf; | |
30 | ||
31 | switch (c) { | |
32 | ||
33 | case '\a': | |
34 | *(buf++) = '\\'; | |
35 | *(buf++) = 'a'; | |
36 | break; | |
37 | case '\b': | |
38 | *(buf++) = '\\'; | |
39 | *(buf++) = 'b'; | |
40 | break; | |
41 | case '\f': | |
42 | *(buf++) = '\\'; | |
43 | *(buf++) = 'f'; | |
44 | break; | |
45 | case '\n': | |
46 | *(buf++) = '\\'; | |
47 | *(buf++) = 'n'; | |
48 | break; | |
49 | case '\r': | |
50 | *(buf++) = '\\'; | |
51 | *(buf++) = 'r'; | |
52 | break; | |
53 | case '\t': | |
54 | *(buf++) = '\\'; | |
55 | *(buf++) = 't'; | |
56 | break; | |
57 | case '\v': | |
58 | *(buf++) = '\\'; | |
59 | *(buf++) = 'v'; | |
60 | break; | |
61 | case '\\': | |
62 | *(buf++) = '\\'; | |
63 | *(buf++) = '\\'; | |
64 | break; | |
65 | case '"': | |
66 | *(buf++) = '\\'; | |
67 | *(buf++) = '"'; | |
68 | break; | |
69 | case '\'': | |
70 | *(buf++) = '\\'; | |
71 | *(buf++) = '\''; | |
72 | break; | |
73 | ||
74 | default: | |
75 | /* For special chars we prefer octal over | |
76 | * hexadecimal encoding, simply because glib's | |
77 | * g_strescape() does the same */ | |
78 | if ((c < ' ') || (c >= 127)) { | |
79 | *(buf++) = '\\'; | |
80 | *(buf++) = octchar((unsigned char) c >> 6); | |
81 | *(buf++) = octchar((unsigned char) c >> 3); | |
82 | *(buf++) = octchar((unsigned char) c); | |
83 | } else | |
84 | *(buf++) = c; | |
85 | break; | |
86 | } | |
87 | ||
88 | return buf - buf_old; | |
89 | } | |
90 | ||
91 | char *cescape(const char *s) { | |
92 | char *r, *t; | |
93 | const char *f; | |
94 | ||
95 | assert(s); | |
96 | ||
97 | /* Does C style string escaping. May be reversed with | |
98 | * cunescape(). */ | |
99 | ||
100 | r = new(char, strlen(s)*4 + 1); | |
101 | if (!r) | |
102 | return NULL; | |
103 | ||
104 | for (f = s, t = r; *f; f++) | |
105 | t += cescape_char(*f, t); | |
106 | ||
107 | *t = 0; | |
108 | ||
109 | return r; | |
110 | } | |
111 | ||
112 | int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode) { | |
113 | int r = 1; | |
114 | ||
115 | assert(p); | |
116 | assert(*p); | |
117 | assert(ret); | |
118 | ||
119 | /* Unescapes C style. Returns the unescaped character in ret, | |
120 | * unless we encountered a \u sequence in which case the full | |
121 | * unicode character is returned in ret_unicode, instead. */ | |
122 | ||
123 | if (length != (size_t) -1 && length < 1) | |
124 | return -EINVAL; | |
125 | ||
126 | switch (p[0]) { | |
127 | ||
128 | case 'a': | |
129 | *ret = '\a'; | |
130 | break; | |
131 | case 'b': | |
132 | *ret = '\b'; | |
133 | break; | |
134 | case 'f': | |
135 | *ret = '\f'; | |
136 | break; | |
137 | case 'n': | |
138 | *ret = '\n'; | |
139 | break; | |
140 | case 'r': | |
141 | *ret = '\r'; | |
142 | break; | |
143 | case 't': | |
144 | *ret = '\t'; | |
145 | break; | |
146 | case 'v': | |
147 | *ret = '\v'; | |
148 | break; | |
149 | case '\\': | |
150 | *ret = '\\'; | |
151 | break; | |
152 | case '"': | |
153 | *ret = '"'; | |
154 | break; | |
155 | case '\'': | |
156 | *ret = '\''; | |
157 | break; | |
158 | ||
159 | case 's': | |
160 | /* This is an extension of the XDG syntax files */ | |
161 | *ret = ' '; | |
162 | break; | |
163 | ||
164 | case 'x': { | |
165 | /* hexadecimal encoding */ | |
166 | int a, b; | |
167 | ||
168 | if (length != (size_t) -1 && length < 3) | |
169 | return -EINVAL; | |
170 | ||
171 | a = unhexchar(p[1]); | |
172 | if (a < 0) | |
173 | return -EINVAL; | |
174 | ||
175 | b = unhexchar(p[2]); | |
176 | if (b < 0) | |
177 | return -EINVAL; | |
178 | ||
179 | /* Don't allow NUL bytes */ | |
180 | if (a == 0 && b == 0) | |
181 | return -EINVAL; | |
182 | ||
183 | *ret = (char) ((a << 4U) | b); | |
184 | r = 3; | |
185 | break; | |
186 | } | |
187 | ||
188 | case 'u': { | |
189 | /* C++11 style 16bit unicode */ | |
190 | ||
191 | int a[4]; | |
192 | unsigned i; | |
193 | uint32_t c; | |
194 | ||
195 | if (length != (size_t) -1 && length < 5) | |
196 | return -EINVAL; | |
197 | ||
198 | for (i = 0; i < 4; i++) { | |
199 | a[i] = unhexchar(p[1 + i]); | |
200 | if (a[i] < 0) | |
201 | return a[i]; | |
202 | } | |
203 | ||
204 | c = ((uint32_t) a[0] << 12U) | ((uint32_t) a[1] << 8U) | ((uint32_t) a[2] << 4U) | (uint32_t) a[3]; | |
205 | ||
206 | /* Don't allow 0 chars */ | |
207 | if (c == 0) | |
208 | return -EINVAL; | |
209 | ||
210 | if (c < 128) | |
211 | *ret = c; | |
212 | else { | |
213 | if (!ret_unicode) | |
214 | return -EINVAL; | |
215 | ||
216 | *ret = 0; | |
217 | *ret_unicode = c; | |
218 | } | |
219 | ||
220 | r = 5; | |
221 | break; | |
222 | } | |
223 | ||
224 | case 'U': { | |
225 | /* C++11 style 32bit unicode */ | |
226 | ||
227 | int a[8]; | |
228 | unsigned i; | |
025b4c41 | 229 | char32_t c; |
4f5dd394 LP |
230 | |
231 | if (length != (size_t) -1 && length < 9) | |
232 | return -EINVAL; | |
233 | ||
234 | for (i = 0; i < 8; i++) { | |
235 | a[i] = unhexchar(p[1 + i]); | |
236 | if (a[i] < 0) | |
237 | return a[i]; | |
238 | } | |
239 | ||
025b4c41 SL |
240 | c = (a[0] << 28U) | (a[1] << 24U) | (a[2] << 20U) | (a[3] << 16U) | |
241 | (a[4] << 12U) | (a[5] << 8U) | (a[6] << 4U) | (a[7] << 0U); | |
4f5dd394 LP |
242 | |
243 | /* Don't allow 0 chars */ | |
244 | if (c == 0) | |
245 | return -EINVAL; | |
246 | ||
247 | /* Don't allow invalid code points */ | |
248 | if (!unichar_is_valid(c)) | |
249 | return -EINVAL; | |
250 | ||
251 | if (c < 128) | |
252 | *ret = c; | |
253 | else { | |
254 | if (!ret_unicode) | |
255 | return -EINVAL; | |
256 | ||
257 | *ret = 0; | |
258 | *ret_unicode = c; | |
259 | } | |
260 | ||
261 | r = 9; | |
262 | break; | |
263 | } | |
264 | ||
265 | case '0': | |
266 | case '1': | |
267 | case '2': | |
268 | case '3': | |
269 | case '4': | |
270 | case '5': | |
271 | case '6': | |
272 | case '7': { | |
273 | /* octal encoding */ | |
274 | int a, b, c; | |
025b4c41 | 275 | char32_t m; |
4f5dd394 LP |
276 | |
277 | if (length != (size_t) -1 && length < 3) | |
278 | return -EINVAL; | |
279 | ||
280 | a = unoctchar(p[0]); | |
281 | if (a < 0) | |
282 | return -EINVAL; | |
283 | ||
284 | b = unoctchar(p[1]); | |
285 | if (b < 0) | |
286 | return -EINVAL; | |
287 | ||
288 | c = unoctchar(p[2]); | |
289 | if (c < 0) | |
290 | return -EINVAL; | |
291 | ||
292 | /* don't allow NUL bytes */ | |
293 | if (a == 0 && b == 0 && c == 0) | |
294 | return -EINVAL; | |
295 | ||
296 | /* Don't allow bytes above 255 */ | |
025b4c41 | 297 | m = (a << 6U) | (b << 3U) | (char32_t) c; |
4f5dd394 LP |
298 | if (m > 255) |
299 | return -EINVAL; | |
300 | ||
301 | *ret = m; | |
302 | r = 3; | |
303 | break; | |
304 | } | |
305 | ||
306 | default: | |
307 | return -EINVAL; | |
308 | } | |
309 | ||
310 | return r; | |
311 | } | |
312 | ||
313 | int cunescape_length_with_prefix(const char *s, size_t length, const char *prefix, UnescapeFlags flags, char **ret) { | |
314 | char *r, *t; | |
315 | const char *f; | |
316 | size_t pl; | |
317 | ||
318 | assert(s); | |
319 | assert(ret); | |
320 | ||
321 | /* Undoes C style string escaping, and optionally prefixes it. */ | |
322 | ||
323 | pl = prefix ? strlen(prefix) : 0; | |
324 | ||
325 | r = new(char, pl+length+1); | |
326 | if (!r) | |
327 | return -ENOMEM; | |
328 | ||
329 | if (prefix) | |
330 | memcpy(r, prefix, pl); | |
331 | ||
332 | for (f = s, t = r + pl; f < s + length; f++) { | |
333 | size_t remaining; | |
025b4c41 | 334 | char32_t u; |
4f5dd394 LP |
335 | char c; |
336 | int k; | |
337 | ||
338 | remaining = s + length - f; | |
339 | assert(remaining > 0); | |
340 | ||
341 | if (*f != '\\') { | |
342 | /* A literal literal, copy verbatim */ | |
343 | *(t++) = *f; | |
344 | continue; | |
345 | } | |
346 | ||
347 | if (remaining == 1) { | |
348 | if (flags & UNESCAPE_RELAX) { | |
349 | /* A trailing backslash, copy verbatim */ | |
350 | *(t++) = *f; | |
351 | continue; | |
352 | } | |
353 | ||
354 | free(r); | |
355 | return -EINVAL; | |
356 | } | |
357 | ||
358 | k = cunescape_one(f + 1, remaining - 1, &c, &u); | |
359 | if (k < 0) { | |
360 | if (flags & UNESCAPE_RELAX) { | |
361 | /* Invalid escape code, let's take it literal then */ | |
362 | *(t++) = '\\'; | |
363 | continue; | |
364 | } | |
365 | ||
366 | free(r); | |
367 | return k; | |
368 | } | |
369 | ||
370 | if (c != 0) | |
371 | /* Non-Unicode? Let's encode this directly */ | |
372 | *(t++) = c; | |
373 | else | |
374 | /* Unicode? Then let's encode this in UTF-8 */ | |
375 | t += utf8_encode_unichar(t, u); | |
376 | ||
377 | f += k; | |
378 | } | |
379 | ||
380 | *t = 0; | |
381 | ||
382 | *ret = r; | |
383 | return t - r; | |
384 | } | |
385 | ||
386 | int cunescape_length(const char *s, size_t length, UnescapeFlags flags, char **ret) { | |
387 | return cunescape_length_with_prefix(s, length, NULL, flags, ret); | |
388 | } | |
389 | ||
390 | int cunescape(const char *s, UnescapeFlags flags, char **ret) { | |
391 | return cunescape_length(s, strlen(s), flags, ret); | |
392 | } | |
393 | ||
394 | char *xescape(const char *s, const char *bad) { | |
395 | char *r, *t; | |
396 | const char *f; | |
397 | ||
398 | /* Escapes all chars in bad, in addition to \ and all special | |
399 | * chars, in \xFF style escaping. May be reversed with | |
400 | * cunescape(). */ | |
401 | ||
402 | r = new(char, strlen(s) * 4 + 1); | |
403 | if (!r) | |
404 | return NULL; | |
405 | ||
406 | for (f = s, t = r; *f; f++) { | |
407 | ||
408 | if ((*f < ' ') || (*f >= 127) || | |
409 | (*f == '\\') || strchr(bad, *f)) { | |
410 | *(t++) = '\\'; | |
411 | *(t++) = 'x'; | |
412 | *(t++) = hexchar(*f >> 4); | |
413 | *(t++) = hexchar(*f); | |
414 | } else | |
415 | *(t++) = *f; | |
416 | } | |
417 | ||
418 | *t = 0; | |
419 | ||
420 | return r; | |
421 | } | |
422 | ||
423 | static char *strcpy_backslash_escaped(char *t, const char *s, const char *bad) { | |
424 | assert(bad); | |
425 | ||
426 | for (; *s; s++) { | |
427 | if (*s == '\\' || strchr(bad, *s)) | |
428 | *(t++) = '\\'; | |
429 | ||
430 | *(t++) = *s; | |
431 | } | |
432 | ||
433 | return t; | |
434 | } | |
435 | ||
436 | char *shell_escape(const char *s, const char *bad) { | |
437 | char *r, *t; | |
438 | ||
439 | r = new(char, strlen(s)*2+1); | |
440 | if (!r) | |
441 | return NULL; | |
442 | ||
443 | t = strcpy_backslash_escaped(r, s, bad); | |
444 | *t = 0; | |
445 | ||
446 | return r; | |
447 | } | |
448 | ||
449 | char *shell_maybe_quote(const char *s) { | |
450 | const char *p; | |
451 | char *r, *t; | |
452 | ||
453 | assert(s); | |
454 | ||
455 | /* Encloses a string in double quotes if necessary to make it | |
456 | * OK as shell string. */ | |
457 | ||
458 | for (p = s; *p; p++) | |
459 | if (*p <= ' ' || | |
460 | *p >= 127 || | |
461 | strchr(SHELL_NEED_QUOTES, *p)) | |
462 | break; | |
463 | ||
464 | if (!*p) | |
465 | return strdup(s); | |
466 | ||
467 | r = new(char, 1+strlen(s)*2+1+1); | |
468 | if (!r) | |
469 | return NULL; | |
470 | ||
471 | t = r; | |
472 | *(t++) = '"'; | |
473 | t = mempcpy(t, s, p - s); | |
474 | ||
475 | t = strcpy_backslash_escaped(t, p, SHELL_NEED_ESCAPE); | |
476 | ||
477 | *(t++)= '"'; | |
478 | *t = 0; | |
479 | ||
480 | return r; | |
481 | } |