add list support
[project/uci.git] / util.c
1 /*
2 * libuci - Library for the Unified Configuration Interface
3 * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU Lesser General Public License version 2.1
7 * as published by the Free Software Foundation
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15 /*
16 * This file contains misc utility functions and wrappers to standard
17 * functions, which throw exceptions upon failure.
18 */
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <sys/file.h>
22 #include <stdbool.h>
23 #include <unistd.h>
24 #include <ctype.h>
25 #include <fcntl.h>
26
27 #define LINEBUF 32
28 #define LINEBUF_MAX 4096
29
30 __plugin void *uci_malloc(struct uci_context *ctx, size_t size)
31 {
32 void *ptr;
33
34 ptr = malloc(size);
35 if (!ptr)
36 UCI_THROW(ctx, UCI_ERR_MEM);
37 memset(ptr, 0, size);
38
39 return ptr;
40 }
41
42 __plugin void *uci_realloc(struct uci_context *ctx, void *ptr, size_t size)
43 {
44 ptr = realloc(ptr, size);
45 if (!ptr)
46 UCI_THROW(ctx, UCI_ERR_MEM);
47
48 return ptr;
49 }
50
51 __plugin char *uci_strdup(struct uci_context *ctx, const char *str)
52 {
53 char *ptr;
54
55 ptr = strdup(str);
56 if (!ptr)
57 UCI_THROW(ctx, UCI_ERR_MEM);
58
59 return ptr;
60 }
61
62 /* Based on an efficient hash function published by D. J. Bernstein */
63 static unsigned int djbhash(unsigned int hash, char *str)
64 {
65 int len = strlen(str);
66 int i;
67
68 /* initial value */
69 if (hash == ~0)
70 hash = 5381;
71
72 for(i = 0; i < len; i++) {
73 hash = ((hash << 5) + hash) + str[i];
74 }
75 return (hash & 0x7FFFFFFF);
76 }
77
78 /*
79 * validate strings for names and types, reject special characters
80 * for names, only alphanum and _ is allowed (shell compatibility)
81 * for types, we allow more characters
82 */
83 __plugin bool uci_validate_str(const char *str, bool name)
84 {
85 if (!*str)
86 return false;
87
88 while (*str) {
89 char c = *str;
90 if (!isalnum(c) && c != '_') {
91 if (name || (c < 33) || (c > 126))
92 return false;
93 }
94 str++;
95 }
96 return true;
97 }
98
99 static inline bool uci_validate_name(const char *str)
100 {
101 return uci_validate_str(str, true);
102 }
103
104 bool uci_validate_text(const char *str)
105 {
106 while (*str) {
107 if ((*str == '\r') || (*str == '\n') ||
108 ((*str < 32) && (*str != '\t')))
109 return false;
110 str++;
111 }
112 return true;
113 }
114
115 static void uci_alloc_parse_context(struct uci_context *ctx)
116 {
117 ctx->pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
118 }
119
120 int uci_parse_tuple(struct uci_context *ctx, char *str, char **package, char **section, char **option, char **value)
121 {
122 char *last = NULL;
123 bool internal = ctx->internal;
124
125 UCI_HANDLE_ERR(ctx);
126 UCI_ASSERT(ctx, str && package && section && option);
127
128 last = strchr(str, '=');
129 if (last) {
130 *last = 0;
131 last++;
132 }
133
134 *package = strsep(&str, ".");
135 if (!*package || !uci_validate_str(*package, false))
136 goto error;
137
138 *section = strsep(&str, ".");
139 *option = NULL;
140 if (value)
141 *value = NULL;
142 if (!*section)
143 goto lastval;
144
145 *option = strsep(&str, ".");
146 if (!*option)
147 goto lastval;
148
149 lastval:
150 if (last) {
151 if (!value)
152 goto error;
153
154 if (!*last)
155 goto error;
156 *value = last;
157 }
158
159 if (*section && *section[0] && !internal && !uci_validate_name(*section))
160 goto error;
161 if (*option && !uci_validate_name(*option))
162 goto error;
163 if (value && *value && !uci_validate_text(*value))
164 goto error;
165
166 goto done;
167
168 error:
169 UCI_THROW(ctx, UCI_ERR_PARSE);
170
171 done:
172 return 0;
173 }
174
175
176 static void uci_parse_error(struct uci_context *ctx, char *pos, char *reason)
177 {
178 struct uci_parse_context *pctx = ctx->pctx;
179
180 pctx->reason = reason;
181 pctx->byte = pos - pctx->buf;
182 UCI_THROW(ctx, UCI_ERR_PARSE);
183 }
184
185
186 /*
187 * Fetch a new line from the input stream and resize buffer if necessary
188 */
189 static void uci_getln(struct uci_context *ctx, int offset)
190 {
191 struct uci_parse_context *pctx = ctx->pctx;
192 char *p;
193 int ofs;
194
195 if (pctx->buf == NULL) {
196 pctx->buf = uci_malloc(ctx, LINEBUF);
197 pctx->bufsz = LINEBUF;
198 }
199
200 ofs = offset;
201 do {
202 p = &pctx->buf[ofs];
203 p[ofs] = 0;
204
205 p = fgets(p, pctx->bufsz - ofs, pctx->file);
206 if (!p || !*p)
207 return;
208
209 ofs += strlen(p);
210 if (pctx->buf[ofs - 1] == '\n') {
211 pctx->line++;
212 pctx->buf[ofs - 1] = 0;
213 return;
214 }
215
216 if (pctx->bufsz > LINEBUF_MAX/2)
217 uci_parse_error(ctx, p, "line too long");
218
219 pctx->bufsz *= 2;
220 pctx->buf = uci_realloc(ctx, pctx->buf, pctx->bufsz);
221 } while (1);
222 }
223
224 /*
225 * parse a character escaped by '\'
226 * returns true if the escaped character is to be parsed
227 * returns false if the escaped character is to be ignored
228 */
229 static inline bool parse_backslash(struct uci_context *ctx, char **str)
230 {
231 /* skip backslash */
232 *str += 1;
233
234 /* undecoded backslash at the end of line, fetch the next line */
235 if (!**str) {
236 *str += 1;
237 uci_getln(ctx, *str - ctx->pctx->buf);
238 return false;
239 }
240
241 /* FIXME: decode escaped char, necessary? */
242 return true;
243 }
244
245 /*
246 * move the string pointer forward until a non-whitespace character or
247 * EOL is reached
248 */
249 static void skip_whitespace(struct uci_context *ctx, char **str)
250 {
251 restart:
252 while (**str && isspace(**str))
253 *str += 1;
254
255 if (**str == '\\') {
256 if (!parse_backslash(ctx, str))
257 goto restart;
258 }
259 }
260
261 static inline void addc(char **dest, char **src)
262 {
263 **dest = **src;
264 *dest += 1;
265 *src += 1;
266 }
267
268 /*
269 * parse a double quoted string argument from the command line
270 */
271 static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
272 {
273 char c;
274
275 /* skip quote character */
276 *str += 1;
277
278 while ((c = **str)) {
279 switch(c) {
280 case '"':
281 **target = 0;
282 *str += 1;
283 return;
284 case '\\':
285 if (!parse_backslash(ctx, str))
286 continue;
287 /* fall through */
288 default:
289 addc(target, str);
290 break;
291 }
292 }
293 uci_parse_error(ctx, *str, "unterminated \"");
294 }
295
296 /*
297 * parse a single quoted string argument from the command line
298 */
299 static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
300 {
301 char c;
302 /* skip quote character */
303 *str += 1;
304
305 while ((c = **str)) {
306 switch(c) {
307 case '\'':
308 **target = 0;
309 *str += 1;
310 return;
311 default:
312 addc(target, str);
313 }
314 }
315 uci_parse_error(ctx, *str, "unterminated '");
316 }
317
318 /*
319 * parse a string from the command line and detect the quoting style
320 */
321 static void parse_str(struct uci_context *ctx, char **str, char **target)
322 {
323 bool next = true;
324 do {
325 switch(**str) {
326 case '\'':
327 parse_single_quote(ctx, str, target);
328 break;
329 case '"':
330 parse_double_quote(ctx, str, target);
331 break;
332 case '#':
333 **str = 0;
334 /* fall through */
335 case 0:
336 goto done;
337 case ';':
338 next = false;
339 goto done;
340 case '\\':
341 if (!parse_backslash(ctx, str))
342 continue;
343 /* fall through */
344 default:
345 addc(target, str);
346 break;
347 }
348 } while (**str && !isspace(**str));
349 done:
350
351 /*
352 * if the string was unquoted and we've stopped at a whitespace
353 * character, skip to the next one, because the whitespace will
354 * be overwritten by a null byte here
355 */
356 if (**str && next)
357 *str += 1;
358
359 /* terminate the parsed string */
360 **target = 0;
361 }
362
363 /*
364 * extract the next argument from the command line
365 */
366 static char *next_arg(struct uci_context *ctx, char **str, bool required, bool name)
367 {
368 char *val;
369 char *ptr;
370
371 val = ptr = *str;
372 skip_whitespace(ctx, str);
373 if(*str[0] == ';') {
374 *str[0] = 0;
375 *str += 1;
376 } else {
377 parse_str(ctx, str, &ptr);
378 }
379 if (!*val) {
380 if (required)
381 uci_parse_error(ctx, *str, "insufficient arguments");
382 goto done;
383 }
384
385 if (name && !uci_validate_name(val))
386 uci_parse_error(ctx, val, "invalid character in field");
387
388 done:
389 return val;
390 }
391
392 int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result)
393 {
394 UCI_HANDLE_ERR(ctx);
395 UCI_ASSERT(ctx, str != NULL);
396 UCI_ASSERT(ctx, result != NULL);
397
398 if (ctx->pctx) {
399 if (ctx->pctx->file != stream) {
400 uci_cleanup(ctx);
401 }
402 } else {
403 uci_alloc_parse_context(ctx);
404 ctx->pctx->file = stream;
405 }
406 if (!*str) {
407 uci_getln(ctx, 0);
408 *str = ctx->pctx->buf;
409 }
410
411 *result = next_arg(ctx, str, false, false);
412
413 return 0;
414 }
415
416
417 /*
418 * open a stream and go to the right position
419 *
420 * note: when opening for write and seeking to the beginning of
421 * the stream, truncate the file
422 */
423 static FILE *uci_open_stream(struct uci_context *ctx, const char *filename, int pos, bool write, bool create)
424 {
425 struct stat statbuf;
426 FILE *file = NULL;
427 int fd, ret;
428 int mode = (write ? O_RDWR : O_RDONLY);
429
430 if (create)
431 mode |= O_CREAT;
432
433 if (!write && ((stat(filename, &statbuf) < 0) ||
434 ((statbuf.st_mode & S_IFMT) != S_IFREG))) {
435 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
436 }
437
438 fd = open(filename, mode, UCI_FILEMODE);
439 if (fd < 0)
440 goto error;
441
442 if (flock(fd, (write ? LOCK_EX : LOCK_SH)) < 0)
443 goto error;
444
445 ret = lseek(fd, 0, pos);
446
447 if (ret < 0)
448 goto error;
449
450 file = fdopen(fd, (write ? "w+" : "r"));
451 if (file)
452 goto done;
453
454 error:
455 UCI_THROW(ctx, UCI_ERR_IO);
456 done:
457 return file;
458 }
459
460 static void uci_close_stream(FILE *stream)
461 {
462 int fd;
463
464 if (!stream)
465 return;
466
467 fd = fileno(stream);
468 flock(fd, LOCK_UN);
469 fclose(stream);
470 }
471
472