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4f5dd394 LP |
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" | |
b11d6a7b | 25 | #include "string-util.h" |
4f5dd394 LP |
26 | #include "utf8.h" |
27 | #include "util.h" | |
28 | ||
4f5dd394 LP |
29 | size_t cescape_char(char c, char *buf) { |
30 | char * buf_old = buf; | |
31 | ||
32 | switch (c) { | |
33 | ||
34 | case '\a': | |
35 | *(buf++) = '\\'; | |
36 | *(buf++) = 'a'; | |
37 | break; | |
38 | case '\b': | |
39 | *(buf++) = '\\'; | |
40 | *(buf++) = 'b'; | |
41 | break; | |
42 | case '\f': | |
43 | *(buf++) = '\\'; | |
44 | *(buf++) = 'f'; | |
45 | break; | |
46 | case '\n': | |
47 | *(buf++) = '\\'; | |
48 | *(buf++) = 'n'; | |
49 | break; | |
50 | case '\r': | |
51 | *(buf++) = '\\'; | |
52 | *(buf++) = 'r'; | |
53 | break; | |
54 | case '\t': | |
55 | *(buf++) = '\\'; | |
56 | *(buf++) = 't'; | |
57 | break; | |
58 | case '\v': | |
59 | *(buf++) = '\\'; | |
60 | *(buf++) = 'v'; | |
61 | break; | |
62 | case '\\': | |
63 | *(buf++) = '\\'; | |
64 | *(buf++) = '\\'; | |
65 | break; | |
66 | case '"': | |
67 | *(buf++) = '\\'; | |
68 | *(buf++) = '"'; | |
69 | break; | |
70 | case '\'': | |
71 | *(buf++) = '\\'; | |
72 | *(buf++) = '\''; | |
73 | break; | |
74 | ||
75 | default: | |
76 | /* For special chars we prefer octal over | |
77 | * hexadecimal encoding, simply because glib's | |
78 | * g_strescape() does the same */ | |
79 | if ((c < ' ') || (c >= 127)) { | |
80 | *(buf++) = '\\'; | |
81 | *(buf++) = octchar((unsigned char) c >> 6); | |
82 | *(buf++) = octchar((unsigned char) c >> 3); | |
83 | *(buf++) = octchar((unsigned char) c); | |
84 | } else | |
85 | *(buf++) = c; | |
86 | break; | |
87 | } | |
88 | ||
89 | return buf - buf_old; | |
90 | } | |
91 | ||
92 | char *cescape(const char *s) { | |
93 | char *r, *t; | |
94 | const char *f; | |
95 | ||
96 | assert(s); | |
97 | ||
98 | /* Does C style string escaping. May be reversed with | |
99 | * cunescape(). */ | |
100 | ||
101 | r = new(char, strlen(s)*4 + 1); | |
102 | if (!r) | |
103 | return NULL; | |
104 | ||
105 | for (f = s, t = r; *f; f++) | |
106 | t += cescape_char(*f, t); | |
107 | ||
108 | *t = 0; | |
109 | ||
110 | return r; | |
111 | } | |
112 | ||
113 | int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode) { | |
114 | int r = 1; | |
115 | ||
116 | assert(p); | |
117 | assert(*p); | |
118 | assert(ret); | |
119 | ||
120 | /* Unescapes C style. Returns the unescaped character in ret, | |
121 | * unless we encountered a \u sequence in which case the full | |
122 | * unicode character is returned in ret_unicode, instead. */ | |
123 | ||
124 | if (length != (size_t) -1 && length < 1) | |
125 | return -EINVAL; | |
126 | ||
127 | switch (p[0]) { | |
128 | ||
129 | case 'a': | |
130 | *ret = '\a'; | |
131 | break; | |
132 | case 'b': | |
133 | *ret = '\b'; | |
134 | break; | |
135 | case 'f': | |
136 | *ret = '\f'; | |
137 | break; | |
138 | case 'n': | |
139 | *ret = '\n'; | |
140 | break; | |
141 | case 'r': | |
142 | *ret = '\r'; | |
143 | break; | |
144 | case 't': | |
145 | *ret = '\t'; | |
146 | break; | |
147 | case 'v': | |
148 | *ret = '\v'; | |
149 | break; | |
150 | case '\\': | |
151 | *ret = '\\'; | |
152 | break; | |
153 | case '"': | |
154 | *ret = '"'; | |
155 | break; | |
156 | case '\'': | |
157 | *ret = '\''; | |
158 | break; | |
159 | ||
160 | case 's': | |
161 | /* This is an extension of the XDG syntax files */ | |
162 | *ret = ' '; | |
163 | break; | |
164 | ||
165 | case 'x': { | |
166 | /* hexadecimal encoding */ | |
167 | int a, b; | |
168 | ||
169 | if (length != (size_t) -1 && length < 3) | |
170 | return -EINVAL; | |
171 | ||
172 | a = unhexchar(p[1]); | |
173 | if (a < 0) | |
174 | return -EINVAL; | |
175 | ||
176 | b = unhexchar(p[2]); | |
177 | if (b < 0) | |
178 | return -EINVAL; | |
179 | ||
180 | /* Don't allow NUL bytes */ | |
181 | if (a == 0 && b == 0) | |
182 | return -EINVAL; | |
183 | ||
184 | *ret = (char) ((a << 4U) | b); | |
185 | r = 3; | |
186 | break; | |
187 | } | |
188 | ||
189 | case 'u': { | |
190 | /* C++11 style 16bit unicode */ | |
191 | ||
192 | int a[4]; | |
193 | unsigned i; | |
194 | uint32_t c; | |
195 | ||
196 | if (length != (size_t) -1 && length < 5) | |
197 | return -EINVAL; | |
198 | ||
199 | for (i = 0; i < 4; i++) { | |
200 | a[i] = unhexchar(p[1 + i]); | |
201 | if (a[i] < 0) | |
202 | return a[i]; | |
203 | } | |
204 | ||
205 | c = ((uint32_t) a[0] << 12U) | ((uint32_t) a[1] << 8U) | ((uint32_t) a[2] << 4U) | (uint32_t) a[3]; | |
206 | ||
207 | /* Don't allow 0 chars */ | |
208 | if (c == 0) | |
209 | return -EINVAL; | |
210 | ||
211 | if (c < 128) | |
212 | *ret = c; | |
213 | else { | |
214 | if (!ret_unicode) | |
215 | return -EINVAL; | |
216 | ||
217 | *ret = 0; | |
218 | *ret_unicode = c; | |
219 | } | |
220 | ||
221 | r = 5; | |
222 | break; | |
223 | } | |
224 | ||
225 | case 'U': { | |
226 | /* C++11 style 32bit unicode */ | |
227 | ||
228 | int a[8]; | |
229 | unsigned i; | |
dcd12626 | 230 | uint32_t c; |
4f5dd394 LP |
231 | |
232 | if (length != (size_t) -1 && length < 9) | |
233 | return -EINVAL; | |
234 | ||
235 | for (i = 0; i < 8; i++) { | |
236 | a[i] = unhexchar(p[1 + i]); | |
237 | if (a[i] < 0) | |
238 | return a[i]; | |
239 | } | |
240 | ||
dcd12626 LP |
241 | c = ((uint32_t) a[0] << 28U) | ((uint32_t) a[1] << 24U) | ((uint32_t) a[2] << 20U) | ((uint32_t) a[3] << 16U) | |
242 | ((uint32_t) a[4] << 12U) | ((uint32_t) a[5] << 8U) | ((uint32_t) a[6] << 4U) | (uint32_t) a[7]; | |
4f5dd394 LP |
243 | |
244 | /* Don't allow 0 chars */ | |
245 | if (c == 0) | |
246 | return -EINVAL; | |
247 | ||
248 | /* Don't allow invalid code points */ | |
249 | if (!unichar_is_valid(c)) | |
250 | return -EINVAL; | |
251 | ||
252 | if (c < 128) | |
253 | *ret = c; | |
254 | else { | |
255 | if (!ret_unicode) | |
256 | return -EINVAL; | |
257 | ||
258 | *ret = 0; | |
259 | *ret_unicode = c; | |
260 | } | |
261 | ||
262 | r = 9; | |
263 | break; | |
264 | } | |
265 | ||
266 | case '0': | |
267 | case '1': | |
268 | case '2': | |
269 | case '3': | |
270 | case '4': | |
271 | case '5': | |
272 | case '6': | |
273 | case '7': { | |
274 | /* octal encoding */ | |
275 | int a, b, c; | |
dcd12626 | 276 | uint32_t m; |
4f5dd394 LP |
277 | |
278 | if (length != (size_t) -1 && length < 3) | |
279 | return -EINVAL; | |
280 | ||
281 | a = unoctchar(p[0]); | |
282 | if (a < 0) | |
283 | return -EINVAL; | |
284 | ||
285 | b = unoctchar(p[1]); | |
286 | if (b < 0) | |
287 | return -EINVAL; | |
288 | ||
289 | c = unoctchar(p[2]); | |
290 | if (c < 0) | |
291 | return -EINVAL; | |
292 | ||
293 | /* don't allow NUL bytes */ | |
294 | if (a == 0 && b == 0 && c == 0) | |
295 | return -EINVAL; | |
296 | ||
297 | /* Don't allow bytes above 255 */ | |
dcd12626 | 298 | m = ((uint32_t) a << 6U) | ((uint32_t) b << 3U) | (uint32_t) c; |
4f5dd394 LP |
299 | if (m > 255) |
300 | return -EINVAL; | |
301 | ||
302 | *ret = m; | |
303 | r = 3; | |
304 | break; | |
305 | } | |
306 | ||
307 | default: | |
308 | return -EINVAL; | |
309 | } | |
310 | ||
311 | return r; | |
312 | } | |
313 | ||
314 | int cunescape_length_with_prefix(const char *s, size_t length, const char *prefix, UnescapeFlags flags, char **ret) { | |
315 | char *r, *t; | |
316 | const char *f; | |
317 | size_t pl; | |
318 | ||
319 | assert(s); | |
320 | assert(ret); | |
321 | ||
322 | /* Undoes C style string escaping, and optionally prefixes it. */ | |
323 | ||
324 | pl = prefix ? strlen(prefix) : 0; | |
325 | ||
326 | r = new(char, pl+length+1); | |
327 | if (!r) | |
328 | return -ENOMEM; | |
329 | ||
330 | if (prefix) | |
331 | memcpy(r, prefix, pl); | |
332 | ||
333 | for (f = s, t = r + pl; f < s + length; f++) { | |
334 | size_t remaining; | |
dcd12626 | 335 | uint32_t u; |
4f5dd394 LP |
336 | char c; |
337 | int k; | |
338 | ||
339 | remaining = s + length - f; | |
340 | assert(remaining > 0); | |
341 | ||
342 | if (*f != '\\') { | |
343 | /* A literal literal, copy verbatim */ | |
344 | *(t++) = *f; | |
345 | continue; | |
346 | } | |
347 | ||
348 | if (remaining == 1) { | |
349 | if (flags & UNESCAPE_RELAX) { | |
350 | /* A trailing backslash, copy verbatim */ | |
351 | *(t++) = *f; | |
352 | continue; | |
353 | } | |
354 | ||
355 | free(r); | |
356 | return -EINVAL; | |
357 | } | |
358 | ||
359 | k = cunescape_one(f + 1, remaining - 1, &c, &u); | |
360 | if (k < 0) { | |
361 | if (flags & UNESCAPE_RELAX) { | |
362 | /* Invalid escape code, let's take it literal then */ | |
363 | *(t++) = '\\'; | |
364 | continue; | |
365 | } | |
366 | ||
367 | free(r); | |
368 | return k; | |
369 | } | |
370 | ||
371 | if (c != 0) | |
372 | /* Non-Unicode? Let's encode this directly */ | |
373 | *(t++) = c; | |
374 | else | |
375 | /* Unicode? Then let's encode this in UTF-8 */ | |
376 | t += utf8_encode_unichar(t, u); | |
377 | ||
378 | f += k; | |
379 | } | |
380 | ||
381 | *t = 0; | |
382 | ||
383 | *ret = r; | |
384 | return t - r; | |
385 | } | |
386 | ||
387 | int cunescape_length(const char *s, size_t length, UnescapeFlags flags, char **ret) { | |
388 | return cunescape_length_with_prefix(s, length, NULL, flags, ret); | |
389 | } | |
390 | ||
391 | int cunescape(const char *s, UnescapeFlags flags, char **ret) { | |
392 | return cunescape_length(s, strlen(s), flags, ret); | |
393 | } | |
394 | ||
395 | char *xescape(const char *s, const char *bad) { | |
396 | char *r, *t; | |
397 | const char *f; | |
398 | ||
399 | /* Escapes all chars in bad, in addition to \ and all special | |
400 | * chars, in \xFF style escaping. May be reversed with | |
401 | * cunescape(). */ | |
402 | ||
403 | r = new(char, strlen(s) * 4 + 1); | |
404 | if (!r) | |
405 | return NULL; | |
406 | ||
407 | for (f = s, t = r; *f; f++) { | |
408 | ||
409 | if ((*f < ' ') || (*f >= 127) || | |
410 | (*f == '\\') || strchr(bad, *f)) { | |
411 | *(t++) = '\\'; | |
412 | *(t++) = 'x'; | |
413 | *(t++) = hexchar(*f >> 4); | |
414 | *(t++) = hexchar(*f); | |
415 | } else | |
416 | *(t++) = *f; | |
417 | } | |
418 | ||
419 | *t = 0; | |
420 | ||
421 | return r; | |
422 | } | |
423 | ||
424 | static char *strcpy_backslash_escaped(char *t, const char *s, const char *bad) { | |
425 | assert(bad); | |
426 | ||
427 | for (; *s; s++) { | |
428 | if (*s == '\\' || strchr(bad, *s)) | |
429 | *(t++) = '\\'; | |
430 | ||
431 | *(t++) = *s; | |
432 | } | |
433 | ||
434 | return t; | |
435 | } | |
436 | ||
437 | char *shell_escape(const char *s, const char *bad) { | |
438 | char *r, *t; | |
439 | ||
440 | r = new(char, strlen(s)*2+1); | |
441 | if (!r) | |
442 | return NULL; | |
443 | ||
444 | t = strcpy_backslash_escaped(r, s, bad); | |
445 | *t = 0; | |
446 | ||
447 | return r; | |
448 | } | |
449 | ||
450 | char *shell_maybe_quote(const char *s) { | |
451 | const char *p; | |
452 | char *r, *t; | |
453 | ||
454 | assert(s); | |
455 | ||
456 | /* Encloses a string in double quotes if necessary to make it | |
457 | * OK as shell string. */ | |
458 | ||
459 | for (p = s; *p; p++) | |
460 | if (*p <= ' ' || | |
461 | *p >= 127 || | |
462 | strchr(SHELL_NEED_QUOTES, *p)) | |
463 | break; | |
464 | ||
465 | if (!*p) | |
466 | return strdup(s); | |
467 | ||
468 | r = new(char, 1+strlen(s)*2+1+1); | |
469 | if (!r) | |
470 | return NULL; | |
471 | ||
472 | t = r; | |
473 | *(t++) = '"'; | |
474 | t = mempcpy(t, s, p - s); | |
475 | ||
476 | t = strcpy_backslash_escaped(t, p, SHELL_NEED_ESCAPE); | |
477 | ||
478 | *(t++)= '"'; | |
479 | *t = 0; | |
480 | ||
481 | return r; | |
482 | } |